Release 1.6.0

With --raw there is a workaround.

The tolerant approach was cool and nice until you want to edit something
non-interactively and get the warning telling you you might have lost
data after the file was written. Failing fast is most likely the better
option here.

.gitignore

@@ -1,3 +1 @@
 /build
-tests/catch.h
-src/version.h

CHANGELOG.md

@@ -0,0 +1,74 @@
+opustags changelog
+==================
+
+1.6.0 - 2021-01-01
+------------------
+
+- UTF-8 conversion errors are now fatal.
+- Introduce --raw for disabling encoding conversions.
+- Improve platform compatibility.
+
+This also happens to be opustags’s 8-year anniversary!
+
+1.5.1 - 2020-11-21
+------------------
+
+- Improve BSD support.
+
+1.5.0 - 2020-11-08
+------------------
+
+- Introduce --edit for interactive edition.
+
+1.4.0 - 2020-10-04
+------------------
+
+- Preserve permissions when overwriting files.
+- Support multiple files with --in-place.
+- Fix BSD support.
+
+Thanks to Reuben Thomas for contributing the pièce de résistance of this
+release!
+
+1.3.0 - 2019-02-02
+------------------
+
+- Support for non-Unicode systems. Tags are automatically converted to and from the system locale.
+- It is now possible to delete specific NAME=VALUE pairs.
+- Option `--set-all` is now stricter and aborts with an error if the input is not valid.
+- Printing tags will display a warning if the tags contain control characters.
+
+opustags is now more aware of its limitations, and will print more helpful error messages when
+trying to edit an unsupported file. It is also more cautious against corrupted streams.
+
+1.2.0 - 2018-11-25
+------------------
+
+- Preserve extra data in OpusTags past the comments.
+- Improve error reporting.
+- Fix various bugs.
+
+This is the biggest release for opustags. The whole code base was reviewed for robustness and
+clarity. The program is now built as C++14, and the code refactored without sacrificing the
+original simplicity. It is shipped with a new test suite.
+
+1.1.1 - 2018-10-24
+------------------
+
+- Mac OS X support.
+- Tolerate but truncate the data in the OpusTags packet past the comments.
+
+1.1 - 2013-01-02
+----------------
+
+- Add the --in-place option.
+- Fix a bug is --set-all where the last unterminated line was ignored.
+- Remove broken output files on failure.
+
+1.0 - 2013-01-01
+----------------
+
+This is the first release of opustags. It supports all the main feature for basic tag editing.
+
+It was written in a day, and the code is quick and dirty, though the program is simple and
+efficient.

CMakeLists.txt

@@ -1,78 +1,54 @@
-cmake_minimum_required (VERSION 2.8.8)
-project (opustags)
-set(CMAKE_CXX_STANDARD 14)
-set(CMAKE_CXX_STANDARD_REQUIRED on)
-set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/modules/")
-set(CMAKE_SOURCE_DIR "${CMAKE_BINARY_DIR}/../")
+cmake_minimum_required(VERSION 3.9)
 
-# ------------
-# Dependencies
-# ------------
-find_package(Ogg REQUIRED)
-include_directories(${Ogg_INCLUDE_DIR})
-link_directories(${Ogg_LIBRARY_DIRS})
+project(
+	opustags
+	VERSION 1.6.0
+	LANGUAGES CXX
+)
 
-# --------------------
-# Global build options
-# --------------------
-if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wextra")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wold-style-cast")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unused-parameter")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14") # for MinGW-w64
-endif()
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-# -------
-# Version
-# -------
-execute_process(COMMAND git describe --tags --abbrev=0 OUTPUT_VARIABLE VERSION_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
-execute_process(COMMAND git describe --always --dirty --long --tags OUTPUT_VARIABLE VERSION_LONG OUTPUT_STRIP_TRAILING_WHITESPACE)
-if("${VERSION_SHORT}" STREQUAL "")
-    set(VERSION_SHORT "0.0")
-    set(VERSION_LONG "?")
-endif()
-configure_file("${CMAKE_SOURCE_DIR}/src/version.h.in" "${CMAKE_SOURCE_DIR}/src/version.h" @ONLY)
+# opustags is mainly developed with glibc, which introduces a few
+# incompatibilites with BSDs, like getline not being defined by default.
+# _GNU_SOURCE should trigger BSD’s libc GNU compatibility mode to fix that.
+add_definitions(-D_GNU_SOURCE)
 
-# ------------
-# Source files
-# ------------
-file(GLOB_RECURSE common_sources "${CMAKE_SOURCE_DIR}/src/*.cc")
-file(GLOB_RECURSE common_headers "${CMAKE_SOURCE_DIR}/src/*.h")
-file(GLOB_RECURSE test_sources "${CMAKE_SOURCE_DIR}/tests/*.cc")
-file(GLOB_RECURSE test_headers "${CMAKE_SOURCE_DIR}/tests/*.h")
-list(REMOVE_ITEM common_sources "${CMAKE_SOURCE_DIR}/src/main.cc")
-list(REMOVE_ITEM test_sources "${CMAKE_SOURCE_DIR}/tests/main.cc")
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(OGG REQUIRED ogg)
+add_compile_options(${OGG_CFLAGS})
+link_directories(${OGG_LIBRARY_DIRS})
 
-# -------------------
-# 3rd party libraries
-# -------------------
-# Catch
-set(CATCH_PATH "${CMAKE_SOURCE_DIR}/tests/catch.h")
-if (NOT EXISTS "${CATCH_PATH}")
-    message("Downloading Catch...")
-    file(DOWNLOAD "http://raw.githubusercontent.com/philsquared/Catch/master/single_include/catch.hpp" "${CATCH_PATH}")
-endif()
+include(FindIconv)
 
-# ------------
-# Installation
-# ------------
-install(FILES ${CMAKE_SOURCE_DIR}/doc/opustags.1 DESTINATION ${CMAKE_INSTALL_PREFIX}/man/man1)
-install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/opustags DESTINATION ${CMAKE_INSTALL_PREFIX}/bin)
-add_custom_target(uninstall COMMAND
-    rm -f "${CMAKE_INSTALL_PREFIX}/man/man1/opustags.1" &&
-    rm -f "${CMAKE_INSTALL_PREFIX}/bin/opustags" )
+# We need endian.h on Linux, and sys/endian.h on BSD.
+include(CheckIncludeFileCXX)
+check_include_file_cxx(endian.h HAVE_ENDIAN_H)
+check_include_file_cxx(sys/endian.h HAVE_SYS_ENDIAN_H)
 
-# -------------------
-# Linking definitions
-# -------------------
-add_library(common OBJECT ${common_sources} ${common_headers})
-add_executable(opustags "${CMAKE_SOURCE_DIR}/src/main.cc" $<TARGET_OBJECTS:common>)
-add_executable(run_tests "${CMAKE_SOURCE_DIR}/tests/main.cc" $<TARGET_OBJECTS:common> ${test_sources} ${test_headers})
-target_link_libraries(opustags ${OGG_LIBRARY})
-target_link_libraries(run_tests ${OGG_LIBRARY})
-target_include_directories(common BEFORE PUBLIC "${CMAKE_SOURCE_DIR}/src")
-target_include_directories(opustags BEFORE PUBLIC "${CMAKE_SOURCE_DIR}/src")
-target_include_directories(run_tests BEFORE PUBLIC "${CMAKE_SOURCE_DIR}/src")
-target_include_directories(run_tests BEFORE PUBLIC "${CMAKE_SOURCE_DIR}/tests")
+include(CheckStructHasMember)
+check_struct_has_member("struct stat" st_mtim sys/stat.h HAVE_STAT_ST_MTIM LANGUAGE CXX)
+check_struct_has_member("struct stat" st_mtimespec sys/stat.h HAVE_STAT_ST_MTIMESPEC LANGUAGE CXX)
+
+configure_file(src/config.h.in config.h @ONLY)
+include_directories(BEFORE src "${CMAKE_BINARY_DIR}" ${OGG_INCLUDE_DIRS} ${Iconv_INCLUDE_DIRS})
+
+add_library(
+	ot
+	STATIC
+	src/cli.cc
+	src/ogg.cc
+	src/opus.cc
+	src/system.cc
+)
+target_link_libraries(ot PUBLIC ${OGG_LIBRARIES} ${Iconv_LIBRARIES})
+
+add_executable(opustags src/opustags.cc)
+target_link_libraries(opustags ot)
+
+include(GNUInstallDirs)
+install(TARGETS opustags DESTINATION "${CMAKE_INSTALL_BINDIR}")
+configure_file(opustags.1 . @ONLY)
+install(FILES "${CMAKE_BINARY_DIR}/opustags.1" DESTINATION "${CMAKE_INSTALL_MANDIR}/man1")
+
+add_subdirectory(t)

CONTRIBUTING.md

@@ -0,0 +1,71 @@
+# Contributing to opustags
+
+opustags should now be mature enough, and contributions for new features are
+welcome.
+
+Before you open a pull request, you might want to talk about the change you'd
+like to make to make sure it's relevant. In that case, feel free to open an
+issue. You can expect a response within a week.
+
+## Submitting pull requests
+
+opustags has nothing really special, so basic git etiquette is just enough.
+
+Please make focused pull requests, one feature at a time. Don't make huge
+commits. Give clear names to your commits and pull requests. Extended
+descriptions are welcome.
+
+Stay objective in your changes. Adding a feature or fixing a bug is a clear
+improvement, but stylistic changes like renaming a function or moving a few
+braces around won't help the project move forward.
+
+You should check that your changes don't break the test suite by running
+`make check`
+
+Following these practices is important to keep the history clean, and to allow
+for better code reviews.
+
+## History of opustags
+
+opustags is originally a small project made to fill a need to edit tags in Opus
+audio files when most taggers didn't support Opus at all. It was written in C
+with libogg, and should be very light and fast compared to most alternatives.
+However, because it was written on a whim, the code is hardly structured and
+might even be fragile, who knows.
+
+An ambitious desire to rewrite it in C++ with bells and whistles gave birth to
+the `next` branch, but sadly it wasn't finalized and is currently not usable,
+though it contains good pieces of code.
+
+With the growing support of Opus in tag editors, the usefulness of opustags was
+questioned, and it was thus abandoned for a few years. Judging by the
+inquiries and contributions, albeit few, on GitHub, it looks like it remains
+relevant, so let's dust it off a bit.
+
+Today, opustags is written in C++ and features a unit test suite in C++, and
+an integration test suite in Perl. The code was refactored, organized into
+modules, and reviewed for safety.
+
+1.3.0 was focused on correctness, and detects edge cases as early as possible,
+instead of hoping something will eventually fail if something is weird.
+
+## Candidate features
+
+The code contains a few `\todo` markers where something could be improved in the
+code.
+
+More generally, here are a few features that could be added in the future:
+
+- Discouraging non-ASCII field names.
+- Logicial stream listing and selection for multiplexed files.
+- Escaping control characters with --escape.
+- Dump binary packets with --binary.
+- Edition of the vendor string.
+- Edition of the arbitrary binary block past the comments.
+- Support for OpusTags packets spanning multiple pages (> 64 kB).
+- Interactive edition of comments inside the EDITOR (--edit).
+- Support for cover arts.
+- Load tags from a file with --set-all=tags.txt.
+- Colored output.
+
+Don't hesitate to contact me before you do anything, I'll give you directions.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2013, Frédéric Mangano
+Copyright (c) 2013-2018, Frédéric Mangano-Tarumi
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,

README.md

@@ -1,45 +1,67 @@
 opustags
 ========
 
-View and edit Opus comments.
+View and edit Ogg Opus comments.
+
+opustags is designed to be fast and as conservative as possible, to the point that if you edit tags
+then edit them again to their previous values, you should get a bit-perfect copy of the original
+file. No under-the-cover operation like writing "edited with opustags" or timestamp tagging will
+ever be performed.
+
+It currently has the following limitations:
+
+- The total size of all tags cannot exceed 64 kB, the maximum size of one Ogg page.
+- Multiplexed streams are not supported.
+- Newlines inside tags are not supported by `--set-all`.
+
+If you'd like one of these limitations lifted, please do open an issue explaining your use case.
+Feel free to ask for new features too.
 
 Requirements
 ------------
 
-* A POSIX-compliant system,
-* `libogg`.
+* a POSIX-compliant system,
+* a C++17 compiler,
+* CMake ≥ 3.9,
+* libogg 1.3.3.
+
+The version numbers are indicative, and it's very likely opustags will build and work fine with
+other versions too, as CMake and libogg are quite mature.
 
 Installing
 ----------
 
-    mkdir build && cd build
-    cmake ..
+opustags is a commonplace CMake project.
+
+Here's how to install it in your `.local`, under your home:
+
+    mkdir build
+    cd build
+    cmake -DCMAKE_INSTALL_PREFIX=~/.local ..
     make
     make install
 
+Note that you don't need to install opustags in order to run it, as the executable is standalone.
+
 Documentation
 -------------
 
     Usage: opustags --help
-           opustags [OPTIONS] INPUT
-           opustags [OPTIONS] -o OUTPUT INPUT
+           opustags [OPTIONS] FILE
+           opustags OPTIONS -i FILE...
+           opustags OPTIONS FILE -o FILE
 
     Options:
-      -h, --help              print this help
-      -V, --version           print version
-      -o, --output FILE       write the modified tags to this file
-      -i, --in-place [SUFFIX] use a temporary file then replace the original file
-      -y, --overwrite         overwrite the output file if it already exists
-          --stream ID         select stream for the next operations
-      -l, --list              display a pretty listing of all tags
-          --no-color          disable colors in --list output
-      -d, --delete FIELD      delete all the fields of a specified type
-      -a, --add FIELD=VALUE   add a field
-      -s, --set FIELD=VALUE   delete then add a field
-      -D, --delete-all        delete all the fields!
-          --full              enable full file scan
-          --export            dump the tags to standard output for --import
-          --import            set the tags from scratch basing on stanard input
-      -e, --edit              spawn the $EDITOR and apply --import on the result
+      -h, --help                    print this help
+      -o, --output FILE             specify the output file
+      -i, --in-place                overwrite the input files
+      -y, --overwrite               overwrite the output file if it already exists
+      -a, --add FIELD=VALUE         add a comment
+      -d, --delete FIELD[=VALUE]    delete previously existing comments
+      -D, --delete-all              delete all the previously existing comments
+      -s, --set FIELD=VALUE         replace a comment
+      -S, --set-all                 import comments from standard input
+      -e, --edit                    edit tags interactively in VISUAL/EDITOR
+      --raw                         disable encoding conversion
 
 See the man page, `opustags.1`, for extensive documentation.

doc/opustags.1

@@ -1,209 +0,0 @@
-.TH opustags 1 "2016"
-.SH NAME
-opustags \- Opus comment editor
-.SH SYNOPSIS
-.B opustags \-\-help
-.br
-.B opustags
-.RI [ OPTIONS ]
-.I INPUT
-.br
-.B opustags
-.RI [ OPTIONS ]
-.B \-o
-.I OUTPUT INPUT
-.SH DESCRIPTION
-.PP
-\fBopustags\fP can read and edit the comment header of an Opus file.
-It has two modes of operation: read\-only for tag listing, and read\-write for
-tag edition.
-.PP
-Edition mode is triggered by the \fB\-\-ouput\fP and \fB\-\-in\-place\fP
-options. Otherwise, the default mode is listing.
-.PP
-Edition options are incompatible in listing mode, the same way as listing
-options are incompatible in edition mode.
-.PP
-\fIINPUT\fP can either be the name of a file or \fB\-\fP to read from standard input.
-.SS Listing
-.PP
-In listing mode, the tags are printed on standard output. Two listing formats
-are available: pretty and raw. By default, pretty listing is implied if the
-output is a terminal, and raw listing if it isn't.
-.PP
-Pretty listing is enabled with the option \fB\-\-list\fP. Colors are enabled
-unless you use the \fB\-\-no\-color\fP option.
-.PP
-Dumping with \fB\-\-export\fP outputs the raw tags in UTF-8, for automatic
-processing. You can restore exported tags with the \fB\-\-import\fP option.
-.SS Editing
-.PP
-As for the edition mode, you need to specify an output file (or \fB\-\fP for
-standard output). It must be different from the input file. You may want to
-use \fB\-\-overwrite\fP if you know what you're doing. To overwrite the input
-file, use \fB\-\-in\-place\fP.
-.PP
-Tag edition is done with the \fB\-\-add\fP, \fB\-\-delete\fP and \fB\-\-set\fP
-options. You can use these options as many times as you wish.
-.PP
-You can delete all the tags with \fB\-\-delete\-all\fP. This operation can be
-combined with \fB\-\-add\fP to set new tags without being bothered by the old
-ones.
-.PP
-If you want to process tags yourself, you can use the \fB\-\-import\fP option
-which will cause \fBopustags\fP to read tags from standard input. The format
-is the same as the one used for output with \fB\-\-export\fP.
-Note that this option implies \fB\-\-delete\-all\fP.
-Also, input is read as UTF-8.
-.PP
-You can use \fB\-\-edit\fP to spawn your \fBEDITOR\fP and edit the tags
-interactively. In read\-write mode, if no other option is specified, this one
-is implied.
-.SS Stream Selection
-.PP
-In case an Ogg file contains multiple streams, the \fB\-\-stream\fP option lets
-you specify the particular streams to modify. You can modify several streams in
-different ways by using this option more than once. Only operations specified
-after this option and relevant, and until another \fB\-\-stream\fP option is
-found.
-.PP
-	opustags \-\-stream 1 \-\-stream 2 \-\-list # BAD
-.PP
-The above command would only show the second stream. To display both streams,
-use instead:
-.PP
-	opustags \-\-stream 1,2 \-\-list
-.PP
-See also the examples at the end of this page, and the documentation of the
-\fB\-\-stream\fP option.
-.PP
-You can easily find the id's of the available streams by calling opustags with
-no options to list the tags. Usually, you'll only have one stream, id 1.
-.SH OPTIONS
-.SS General
-.TP
-.B \-h, \-\-help
-Display a brief description of the options.
-.TP
-.B \-V, \-\-version
-Display the version of opustags.
-.TP
-.B \-\-stream \fIID\fP
-Specify the stream that will be affected by the options following it. The
-special id \fBall\fP selects all the Opus streams found, and is the default
-value.
-.sp
-The identifer of a stream is determined from its position in the file. The
-first stream found will have id 1, the second 2, and so on.
-.sp
-You can select more than one stream with this option by separated id's with commas. For example: \-\-stream 1,3. Ranges are not supported.
-.sp
-In edition mode, this option should be set if the input file contains more than
-one Opus stream, otherwise a warning is generated. If in\-place modification is
-selected, this warning becomes a fatal error.
-.SS Listing
-.TP
-.B \-l, \-\-list
-Display a pretty listing of all the tags found. This is the default option in
-read\-only mode if the standard output is a terminal.
-.TP
-.B \-\-no\-color
-By default, when listing tags with \fB\-\-list\fP, colors are used. Use this
-option to disable it.
-.TP
-.B \-\-export
-Dump the tags on standard output in a format compatible with \fB\-\-import\fP.
-If only one stream is specified, the output format is compatible with other
-tools such as vorbiscomment.
-.sp
-When exporting, output is encoded in UTF\-8 in
-order not to lose information.
-.TP
-.B \-\-full
-For performance reasons, only the beginning of the input is read, because
-that's where tags are expected. If, however, you think you have an
-unconventional file and you suspect that opustags is missing some streams, you
-can use this option to force it to read the whole file.
-.sp
-This option shouldn't be needed, but if you do find files that require this
-option, please submit a bug report (see the bottom of the page).
-.SS Edition
-.TP
-.B \-o, \-\-output \fIFILE\fI
-Edition mode. The input file will be read, its tags edited, then written to the
-specified output file. If \fIFILE\fP is \fB\-\fP then the resulting Opus file
-will be written to standard output. The output file can't be the same as the
-input file, use \fB\-\-in\-place\fP instead. This option may be specified at
-most once.
-.TP
-.B \-i, \-\-in\-place \fR[\fP\fISUFFIX\fP\fR]\fP
-Use this when you want to modify the input file in\-place. This creates a
-temporary file with the specified suffix (\fI.otmp\fP by default). This implies
-\fB\-\-overwrite\fP in that if a file with the same temporary name already
-exists, it will be overwritten without warning. Of course, this overwrites the
-input file too. You cannot use this option when the input file is the standard
-input.
-.TP
-.B \-y, \-\-overwrite
-By default, opustags refuses to overwrite an already existent file. Use
-this option to allow that.
-.TP
-.B \-d, \-\-delete \fIFIELD\fP
-Delete all the tags whose field name is \fIFIELD\fP. Note that one tag key,
-like \fIARTIST\fP, may appear more than once, in which case all of those are
-deleted.
-.TP
-.B \-a, \-\-add \fIFIELD=VALUE\fP
-Add a tag. It doesn't matter if a tag of the same type already exist (think
-about the case where there are several artists).
-.TP
-.B \-s, \-\-set \fIFIELD=VALUE\fP
-This option is provided for convenience. It deletes all the fields of the same
-type that may already exist, then adds it with the wanted value. This is
-strictly equivalent to \fB\-\-delete\fP \fIFIELD\fP \fB\-\-add\fP
-\fIFIELD=VALUE\fP.
-You can combine it with \fB\-\-add\fP to add more tags with that same \fIFIELD\fP.
-.TP
-.B \-D, \-\-delete\-all
-Delete all the tags before adding any.
-.TP
-.B \-\-import
-Set the tags from scratch. All the original tags are deleted and new ones are
-read from standard input.
-.sp
-Each line must specify a \fIFIELD=VALUE\fP pair and be LF\-terminated (except
-for the last line). Invalid lines are skipped and issue a warning. Blank lines
-are ignored. Lines whose first non-blank character is \fB#\fP are ignored.
-Blank characters at the beginning of a line are also skipped.
-.sp
-Input is read as UTF\-8, disregarding the current locale of your system.
-.TP
-.B \-e, \-\-edit
-Spawn the program specified in the environment variable \fBEDITOR\fP to edit
-tags interactively. If this variable can't be read or is empty, an error
-message is displayed.
-.sp
-The expected format is the same as the one \fB\-\-import\fP expects.
-.SH EXAMPLES
-Here's how you would list all tags in a stream:
-.PP
-	opustags in.ogg
-.PP
-Here's how you would edit two streams at once, setting the title and artist of
-the first, and only the title of the second:
-.PP
-	opustags \-\-stream 1 \-\-set TITLE=X \-\-set ARTIST=Y \-\-stream 2 \-\-set TITLE=Y in.ogg \-o out.ogg
-.PP
-Here's how you would set two artists:
-.PP
-	opustags \-\-delete ARTIST \-\-add ARTIST=A \-\-add ARTIST=B in.ogg \-o out.ogg
-.PP
-Hoping that helped!
-.SH SEE ALSO
-.BR vorbiscomment (1),
-.BR sed (1)
-.SH AUTHORS
-Frédéric Mangano <fmang+opustags@mg0.fr>,
-rr\- <https://github.com/rr\->.
-.PP
-Please report issues on GitHub at <https://github.com/fmang/opustags/issues>.

modules/FindOgg.cmake

@@ -1,23 +0,0 @@
-# Base Io build system
-# Written by Jeremy Tregunna <jeremy.tregunna@me.com>
-#
-# Find libogg.
-
-FIND_PATH(OGG_INCLUDE_DIR ogg/ogg.h)
-
-SET(OGG_NAMES ${OGG_NAMES} ogg libogg)
-FIND_LIBRARY(OGG_LIBRARY NAMES ${OGG_NAMES} PATH)
-
-IF(OGG_INCLUDE_DIR AND OGG_LIBRARY)
-	SET(OGG_FOUND TRUE)
-ENDIF(OGG_INCLUDE_DIR AND OGG_LIBRARY)
-
-IF(OGG_FOUND)
-	IF(NOT Ogg_FIND_QUIETLY)
-		MESSAGE(STATUS "Found Ogg: ${OGG_LIBRARY}")
-	ENDIF (NOT Ogg_FIND_QUIETLY)
-ELSE(OGG_FOUND)
-	IF(Ogg_FIND_REQUIRED)
-		MESSAGE(FATAL_ERROR "Could not find ogg")
-	ENDIF(Ogg_FIND_REQUIRED)
-ENDIF (OGG_FOUND)

opustags.1

@@ -0,0 +1,156 @@
+.TH opustags 1 "December 2018" "@PROJECT_NAME@ @PROJECT_VERSION@"
+.SH NAME
+opustags \- Ogg Opus tag editor
+.SH SYNOPSIS
+.B opustags --help
+.br
+.B opustags
+.RI [ OPTIONS ]
+.I INPUT
+.br
+.B opustags
+.I OPTIONS
+.B -i
+.R \fIFILE\fP...
+.br
+.B opustags
+.I OPTIONS
+.B -o
+.I OUTPUT INPUT
+.SH DESCRIPTION
+.PP
+\fBopustags\fP can read and edit the comment header of an Ogg Opus file.
+It basically has two modes: read-only, and read-write for tag editing.
+.PP
+In read-only mode, only the beginning of \fIINPUT\fP is read, and the tags are
+printed on standard output.
+\fIINPUT\fP can either be the name of a file or \fB-\fP to read from standard input.
+You can use the options below to edit the tags before printing them.
+This could be useful to preview some changes before writing them.
+.PP
+In editing mode, you need to specify an output file with \fB--output\fP, or use \fB--in-place\fP to
+overwrite the input files. If the output is a regular file, the result is first written to a
+temporary file and then moved to its final location on success. On error, the temporary output file
+is deleted.
+.PP
+Tag editing can be performed with the \fB--add\fP, \fB--delete\fP and \fB--set\fP
+options. Options can be specified in any order and don’t conflict with each other.
+First the specified tags are deleted, then the new tags are added.
+.PP
+You can delete all the tags with \fB--delete-all\fP. This operation can be combined with \fB--add\fP
+to set new tags without being bothered by the old ones.
+.PP
+If you want to replace all the tags, you can use the \fB--set-all\fP option which will cause
+\fBopustags\fP to read tags from standard input.
+The format is the same as the one used for output: newline-separated \fIFIELD=Value\fP assignment.
+All the previously existing tags as deleted.
+.PP
+The Opus format specifications requires that tags are encoded in UTF-8, so that's the only encoding
+opustags supports. If your system encoding is different, the tags are automatically converted to and
+from your system locale. When the conversion is lossy, the incompatible characters are
+transliterated and a warning is displayed. Even if you edit an Opus file whose tags contains
+characters unsupported by your system encoding, the original UTF-8 values will be preserved for the
+tags you don't explictly modify.
+.SH OPTIONS
+.TP
+.B \-h, \-\-help
+Display a brief description of the options.
+.TP
+.B \-o, \-\-output \fIFILE\fI
+Specify the output file.
+The input file will be read, its tags edited, then written to the specified output file. If
+\fIFILE\fP is \fB-\fP then the resulting Opus file will be written to standard output.
+The output file can’t be the same as the input file.
+.TP
+.B \-i, \-\-in-place
+Overwrite the input file instead of creating a separate output file. It has the same effect as
+setting \fB--output\fP to the same path as the input file and enabling \fB--overwrite\fP.
+This option conflicts with \fB--output\fP.
+.TP
+.B \-y, \-\-overwrite
+By default, \fBopustags\fP refuses to overwrite an already-existent file.
+Use \fB-y\fP to allow overwriting.
+Note that this option is not needed when the output is a special file like \fI/dev/null\fP.
+.TP
+.B \-d, \-\-delete \fIFIELD[=VALUE]\fP
+If value is not specified, delete all the tags whose field name is \fIFIELD\fP.
+Otherwise, delete all the comments whose field name is \fIFIELD\fP and value is \fIVALUE\fP.
+In both cases, the field names are case-insensitive, and expected to be ASCII.
+.TP
+.B \-a, \-\-add \fIFIELD=VALUE\fP
+Add a tag. Note that multiple tags with the same field name are perfectly acceptable, so you can add
+multiple fields with the same name, and previously existing tags will also be preserved.
+When the \fB--delete\fP is used with the same \fIFIELD\fP, only the older tags are deleted.
+.TP
+.B \-s, \-\-set \fIFIELD=VALUE\fP
+This option is provided for convenience. It delete all the fields of the same
+type that may already exist, then adds it with the wanted value.
+This is strictly equivalent to \fB--delete\fP \fIFIELD\fP \fB--add\fP
+\fIFIELD=VALUE\fP. You can combine it with \fB--add\fP to add tags of the same
+type. As deletion occurs before adding, \fB--set\fP won’t erase the tags
+added with \fB--add\fP.
+.TP
+.B \-D, \-\-delete-all
+Delete all the previously existing tags.
+.TP
+.B \-S, \-\-set-all
+Sets the tags from scratch.
+All the original tags are deleted and new ones are read from standard input.
+Each line must specify a \fIFIELD=VALUE\fP pair and be separated with line feeds.
+Blank lines and lines starting with \fI#\fP are ignored.
+.TP
+.B \-e, \-\-edit
+Edit tags interactively by spawning the program specified by the EDITOR
+environment variable. The allowed format is the same as \fB--set-all\fP.
+If TERM and VISUAL are set, VISUAL takes precedence over EDITOR.
+.TP
+.B \-\-raw
+OpusTags metadata should always be encoded in UTF-8, as per RFC 7845. However, some files may be
+corrupted or possibly even contain intentional binary data. In that case, --raw lets you edit that
+kind of binary data without ensuring the validity of the tags encoding. This option may also be
+useful when your system encoding is different from UTF-8 and you wish to preserve the full UTF-8
+character set even though your system cannot display it.
+.SH EXAMPLES
+.PP
+List all the tags in file foo.opus:
+.PP
+	opustags foo.opus
+.PP
+Copy in.opus to out.opus, with the TITLE tag added:
+.PP
+	opustags in.opus --output out.opus --add "TITLE=Hello world!"
+.PP
+Replace all the tags in dest.opus with the ones from src.opus:
+.PP
+	opustags src.opus | opustags --in-place dest.opus --set-all
+.PP
+Remove the previously existing ARTIST tags and add the two X and Y ARTIST tags, then display the new
+tags without writing them to the Opus file:
+.PP
+	opustags in.opus --add ARTIST=X --add ARTIST=Y --delete ARTIST
+.PP
+Edit tags interactively in Vim:
+.PP
+	EDITOR=vim opustags --in-place --edit file.opus
+.SH CAVEATS
+.PP
+\fBopustags\fP currently has the following limitations:
+.IP \[bu]
+The total size of all tags cannot exceed 64 kB, the maximum size of one Ogg page.
+.IP \[bu]
+Multiplexed streams are not supported.
+.IP \[bu]
+Newlines inside tags are not supported by `--set-all`.
+.IP \[bu]
+Newlines and control characters are not escaped when printing tags.
+.PP
+Internally, the OpusTags packet in an Ogg Opus file may contain extra arbitrary binary data after
+the comments.  This block of data is currently not editable, but is always preserved. The same
+applies for the vendor string.
+.PP
+If you need a feature not currently supported, feel free to open an issue or send an email with your
+use case.
+.SH AUTHOR
+Frédéric Mangano-Tarumi <fmang+opustags@mg0.fr>
+.PP
+Report bugs at <https://github.com/fmang/opustags/issues>

src/actions.cc

@@ -1,83 +0,0 @@
-#include "actions.h"
-
-using namespace opustags;
-
-void opustags::list_tags(ogg::Decoder &dec, ITagsHandler &handler, bool full)
-{
-    std::map<long, int> sequence_numbers;
-    int stream_count = 0;
-    int remaining_streams = 0;
-    std::shared_ptr<ogg::Stream> s;
-    while (!handler.done()) {
-        s = dec.read_page();
-        if (s == nullptr)
-            break; // end of stream
-        switch (s->state) {
-            case ogg::HEADER_READY:
-                stream_count++;
-                sequence_numbers[s->stream.serialno] = stream_count;
-                handler.start_of_stream(stream_count, s->type);
-                if (!handler.relevant(stream_count))
-                    s->downgrade();
-                remaining_streams++;
-                break;
-            case ogg::TAGS_READY:
-                handler.list(sequence_numbers[s->stream.serialno], s->tags);
-                s->downgrade(); // no more use for it
-            default:
-                remaining_streams--;
-        }
-        if (!full && remaining_streams <= 0) {
-            break;
-            // premature exit, but calls end_of_stream anyway
-            // we want our optimization to be transparent to the TagsHandler
-        }
-    }
-    handler.end_of_file();
-}
-
-void opustags::edit_tags(
-    ogg::Decoder &in, ogg::Encoder &out, ITagsHandler &handler)
-{
-    std::map<long, int> sequence_numbers;
-    int stream_count = 0;
-    std::shared_ptr<ogg::Stream> s;
-    for (;;) {
-        s = in.read_page();
-        if (s == nullptr)
-            break; // end of stream
-        switch (s->state) {
-
-            case ogg::HEADER_READY:
-                stream_count++;
-                sequence_numbers[s->stream.serialno] = stream_count;
-                handler.start_of_stream(stream_count, s->type);
-                if (!handler.relevant(stream_count))
-                    s->downgrade(); // makes it UNKNOWN
-                if (s->type == ogg::UNKNOWN_STREAM) {
-                    out.write_raw_page(in.current_page);
-                } else {
-                    out.forward(*s);
-                }
-                break;
-
-            case ogg::TAGS_READY:
-                handler.edit(sequence_numbers[s->stream.serialno], s->tags);
-                handler.list(sequence_numbers[s->stream.serialno], s->tags);
-                out.write_tags(s->stream.serialno, s->tags);
-                break;
-
-            case ogg::DATA_READY:
-                out.forward(*s);
-                break;
-
-            case ogg::RAW_READY:
-                out.write_raw_page(in.current_page);
-                break;
-
-            default:
-                ;
-        }
-    }
-    handler.end_of_file();
-}

src/actions.h

@@ -1,33 +0,0 @@
-#pragma once
-
-#include "ogg.h"
-#include "tags_handler.h"
-
-namespace opustags {
-
-    // Decode a file and call the handler's list method every time a tags
-    // header is read. Set full to true if you want to make sure every single
-    // page of the stream is read.
-    //
-    // Use:
-    //   std::ifstream in("in.ogg");
-    //   ogg::Decoder dec(in);
-    //   TagsLister lister(options);
-    //   list_tags(dec, lister);
-    //
-    void list_tags(ogg::Decoder&, ITagsHandler &, bool full = false);
-
-    // Forward the input data to the output stream, transforming tags on-the-go
-    // with the handler's edit method.
-    //
-    // Use:
-    //   std::ifstream in("in.ogg");
-    //   ogg::Decoder dec(in);
-    //   std::ofstream out("out.ogg");
-    //   std::Encoder enc(out);
-    //   TagsEditor editor(options);
-    //   edit_tags(dec, enc, editor);
-    //
-    void edit_tags(ogg::Decoder &in, ogg::Encoder &out, ITagsHandler &);
-
-}

src/cli.cc

@@ -0,0 +1,519 @@
+/**
+ * \file src/cli.cc
+ * \ingroup cli
+ *
+ * Provide all the features of the opustags executable from a C++ API. The main point of separating
+ * this module from the main one is to allow easy testing.
+ */
+
+#include <opustags.h>
+
+#include <errno.h>
+#include <getopt.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+using namespace std::literals::string_literals;
+
+static const char help_message[] =
+PROJECT_NAME " version " PROJECT_VERSION
+R"raw(
+
+Usage: opustags --help
+       opustags [OPTIONS] FILE
+       opustags OPTIONS -i FILE...
+       opustags OPTIONS FILE -o FILE
+
+Options:
+  -h, --help                    print this help
+  -o, --output FILE             specify the output file
+  -i, --in-place                overwrite the input files
+  -y, --overwrite               overwrite the output file if it already exists
+  -a, --add FIELD=VALUE         add a comment
+  -d, --delete FIELD[=VALUE]    delete previously existing comments
+  -D, --delete-all              delete all the previously existing comments
+  -s, --set FIELD=VALUE         replace a comment
+  -S, --set-all                 import comments from standard input
+  -e, --edit                    edit tags interactively in VISUAL/EDITOR
+  --raw                         disable encoding conversion
+
+See the man page for extensive documentation.
+)raw";
+
+static struct option getopt_options[] = {
+	{"help", no_argument, 0, 'h'},
+	{"output", required_argument, 0, 'o'},
+	{"in-place", optional_argument, 0, 'i'},
+	{"overwrite", no_argument, 0, 'y'},
+	{"delete", required_argument, 0, 'd'},
+	{"add", required_argument, 0, 'a'},
+	{"set", required_argument, 0, 's'},
+	{"delete-all", no_argument, 0, 'D'},
+	{"set-all", no_argument, 0, 'S'},
+	{"edit", no_argument, 0, 'e'},
+	{"raw", no_argument, 0, 'r'},
+	{NULL, 0, 0, 0}
+};
+
+ot::status ot::parse_options(int argc, char** argv, ot::options& opt, FILE* comments_input)
+{
+	static ot::encoding_converter to_utf8("", "UTF-8");
+	std::string utf8;
+	const char* equal;
+	ot::status rc;
+	bool set_all = false;
+	opt = {};
+	if (argc == 1)
+		return {st::bad_arguments, "No arguments specified. Use -h for help."};
+	int c;
+	optind = 0;
+	while ((c = getopt_long(argc, argv, ":ho:iyd:a:s:DSe", getopt_options, NULL)) != -1) {
+		switch (c) {
+		case 'h':
+			opt.print_help = true;
+			break;
+		case 'o':
+			if (opt.path_out)
+				return {st::bad_arguments, "Cannot specify --output more than once."};
+			opt.path_out = optarg;
+			break;
+		case 'i':
+			opt.in_place = true;
+			opt.overwrite = true;
+			break;
+		case 'y':
+			opt.overwrite = true;
+			break;
+		case 'd':
+			opt.to_delete.emplace_back(optarg);
+			break;
+		case 'a':
+		case 's':
+			equal = strchr(optarg, '=');
+			if (equal == nullptr)
+				return {st::bad_arguments, "Comment does not contain an equal sign: "s + optarg + "."};
+			if (c == 's')
+				opt.to_delete.emplace_back(optarg, equal - optarg);
+			opt.to_add.emplace_back(optarg);
+			break;
+		case 'S':
+			opt.delete_all = true;
+			set_all = true;
+			break;
+		case 'D':
+			opt.delete_all = true;
+			break;
+		case 'e':
+			opt.edit_interactively = true;
+			break;
+		case 'r':
+			opt.raw = true;
+			break;
+		case ':':
+			return {st::bad_arguments,
+			        "Missing value for option '"s + argv[optind - 1] + "'."};
+		default:
+			return {st::bad_arguments, "Unrecognized option '" +
+			        (optopt ? "-"s + static_cast<char>(optopt) : argv[optind - 1]) + "'."};
+		}
+	}
+	if (opt.print_help)
+		return st::ok;
+
+	// All non-option arguments are input files.
+	bool stdin_as_input = false;
+	for (int i = optind; i < argc; i++) {
+		stdin_as_input = stdin_as_input || strcmp(argv[i], "-") == 0;
+		opt.paths_in.emplace_back(argv[i]);
+	}
+
+	// Convert arguments to UTF-8.
+	if (!opt.raw) {
+		for (std::list<std::string>* args : { &opt.to_add, &opt.to_delete }) {
+			for (std::string& arg : *args) {
+				rc = to_utf8(arg, utf8);
+				if (rc != ot::st::ok)
+					return {st::bad_arguments, "Could not encode argument into UTF-8: " + rc.message};
+				arg = std::move(utf8);
+			}
+		}
+	}
+
+	if (opt.in_place && opt.path_out)
+		return {st::bad_arguments, "Cannot combine --in-place and --output."};
+
+	if (opt.in_place && stdin_as_input)
+		return {st::bad_arguments, "Cannot modify standard input in place."};
+
+	if ((!opt.in_place || opt.edit_interactively) && opt.paths_in.size() != 1)
+		return {st::bad_arguments, "Exactly one input file must be specified."};
+
+	if (set_all && stdin_as_input)
+		return {st::bad_arguments, "Cannot use standard input as input file when --set-all is specified."};
+
+	if (opt.edit_interactively && (stdin_as_input || opt.path_out == "-"))
+		return {st::bad_arguments, "Cannot edit interactively when standard input or standard output are already used."};
+
+	if (opt.edit_interactively && !opt.path_out.has_value() && !opt.in_place)
+		return {st::bad_arguments, "Cannot edit interactively when no output is specified."};
+
+	if (opt.edit_interactively && (opt.delete_all || !opt.to_add.empty() || !opt.to_delete.empty()))
+		return {st::bad_arguments, "Cannot mix --edit with -adDsS."};
+
+	if (set_all) {
+		// Read comments from stdin and prepend them to opt.to_add.
+		std::list<std::string> comments;
+		auto rc = read_comments(comments_input, comments, opt.raw);
+		if (rc != st::ok)
+			return rc;
+		opt.to_add.splice(opt.to_add.begin(), std::move(comments));
+	}
+	return st::ok;
+}
+
+/**
+ * \todo Find a way to support new lines such that they can be read back by #read_comment without
+ *       ambiguity. We could add a raw mode and separate comments with a \0, or escape control
+ *       characters with a backslash, but we should also preserve compatibiltity with potential
+ *       callers that don’t escape backslashes. Maybe add options to select a mode between simple,
+ *       raw, and escaped.
+ */
+ot::status ot::print_comments(const std::list<std::string>& comments, FILE* output, bool raw)
+{
+	static ot::encoding_converter from_utf8("UTF-8", "");
+	std::string local;
+	bool has_newline = false;
+	bool has_control = false;
+	for (const std::string& utf8_comment : comments) {
+		const std::string* comment;
+		// Convert the comment from UTF-8 to the system encoding if relevant.
+		if (raw) {
+			comment = &utf8_comment;
+		} else {
+			ot::status rc = from_utf8(utf8_comment, local);
+			comment = &local;
+			if (rc != ot::st::ok) {
+				rc.message += " See --raw.";
+				return rc;
+			}
+		}
+
+		for (unsigned char c : *comment) {
+			if (c == '\n')
+				has_newline = true;
+			else if (c < 0x20)
+				has_control = true;
+		}
+		fwrite(comment->data(), 1, comment->size(), output);
+		putc('\n', output);
+	}
+	if (has_newline)
+		fputs("warning: Some tags contain unsupported newline characters.\n", stderr);
+	if (has_control)
+		fputs("warning: Some tags contain control characters.\n", stderr);
+	return st::ok;
+}
+
+ot::status ot::read_comments(FILE* input, std::list<std::string>& comments, bool raw)
+{
+	static ot::encoding_converter to_utf8("", "UTF-8");
+	comments.clear();
+	char* line = nullptr;
+	size_t buflen = 0;
+	ssize_t nread;
+	while ((nread = getline(&line, &buflen, input)) != -1) {
+		if (nread > 0 && line[nread - 1] == '\n')
+			--nread;
+		if (nread == 0)
+			continue;
+		if (line[0] == '#') // comment
+			continue;
+		if (memchr(line, '=', nread) == nullptr) {
+			ot::status rc = {ot::st::error, "Malformed tag: " + std::string(line, nread)};
+			free(line);
+			return rc;
+		}
+		if (raw) {
+			comments.emplace_back(line, nread);
+		} else {
+			std::string utf8;
+			ot::status rc = to_utf8(std::string_view(line, nread), utf8);
+			if (rc == ot::st::ok) {
+				comments.emplace_back(std::move(utf8));
+			} else {
+				free(line);
+				return {ot::st::badly_encoded, "UTF-8 conversion error: " + rc.message};
+			}
+		}
+	}
+	free(line);
+	return ot::st::ok;
+}
+
+void ot::delete_comments(std::list<std::string>& comments, const std::string& selector)
+{
+	auto name = selector.data();
+	auto equal = selector.find('=');
+	auto value = (equal == std::string::npos ? nullptr : name + equal + 1);
+	auto name_len = value ? equal : selector.size();
+	auto value_len = value ? selector.size() - equal - 1 : 0;
+	auto it = comments.begin(), end = comments.end();
+	while (it != end) {
+		auto current = it++;
+		bool name_match = current->size() > name_len + 1 &&
+		                  (*current)[name_len] == '=' &&
+		                  strncasecmp(current->data(), name, name_len) == 0;
+		if (!name_match)
+			continue;
+		bool value_match = value == nullptr ||
+		                   (current->size() == selector.size() &&
+		                    memcmp(current->data() + equal + 1, value, value_len) == 0);
+		if (value_match)
+			comments.erase(current);
+	}
+}
+
+/** Apply the modifications requested by the user to the opustags packet. */
+static ot::status edit_tags(ot::opus_tags& tags, const ot::options& opt)
+{
+	if (opt.delete_all) {
+		tags.comments.clear();
+	} else for (const std::string& name : opt.to_delete) {
+		ot::delete_comments(tags.comments, name.c_str());
+	}
+
+	for (const std::string& comment : opt.to_add)
+		tags.comments.emplace_back(comment);
+
+	return ot::st::ok;
+}
+
+/** Spawn VISUAL or EDITOR to edit the given tags. */
+static ot::status edit_tags_interactively(ot::opus_tags& tags, const std::optional<std::string>& base_path, bool raw)
+{
+	const char* editor = nullptr;
+	if (getenv("TERM") != nullptr)
+		editor = getenv("VISUAL");
+	if (editor == nullptr) // without a terminal, or if VISUAL is unset
+		editor = getenv("EDITOR");
+	if (editor == nullptr)
+		return {ot::st::error,
+		        "No editor specified in environment variable VISUAL or EDITOR."};
+
+	// Building the temporary tags file.
+	ot::status rc;
+	std::string tags_path = base_path.value_or("tags") + ".XXXXXX.opustags";
+	int fd = mkstemps(const_cast<char*>(tags_path.data()), 9);
+	ot::file tags_file;
+	if (fd == -1 || (tags_file = fdopen(fd, "w")) == nullptr)
+		return {ot::st::standard_error,
+		        "Could not open '" + tags_path + "': " + strerror(errno)};
+	if ((rc = ot::print_comments(tags.comments, tags_file.get(), raw)) != ot::st::ok)
+		return rc;
+	tags_file.reset();
+
+	// Spawn the editor, and watch the modification timestamps.
+	timespec before, after;
+	if ((rc = ot::get_file_timestamp(tags_path.c_str(), before)) != ot::st::ok)
+		return rc;
+	ot::status editor_rc = ot::run_editor(editor, tags_path);
+	if ((rc = ot::get_file_timestamp(tags_path.c_str(), after)) != ot::st::ok)
+		return rc; // probably because the file was deleted
+	bool modified = (before.tv_sec != after.tv_sec || before.tv_nsec != after.tv_nsec);
+	if (editor_rc != ot::st::ok) {
+		if (modified)
+			fprintf(stderr, "warning: Leaving %s on the disk.\n", tags_path.c_str());
+		else
+			remove(tags_path.c_str());
+		return editor_rc;
+	} else if (!modified) {
+		remove(tags_path.c_str());
+		fputs("Cancelling edition because the tags file was not modified.\n", stderr);
+		return ot::st::cancel;
+	}
+
+	// Applying the new tags.
+	tags_file = fopen(tags_path.c_str(), "re");
+	if (tags_file == nullptr)
+		return {ot::st::standard_error, "Error opening " + tags_path + ": " + strerror(errno)};
+	if ((rc = ot::read_comments(tags_file.get(), tags.comments, raw)) != ot::st::ok) {
+		fprintf(stderr, "warning: Leaving %s on the disk.\n", tags_path.c_str());
+		return rc;
+	}
+	tags_file.reset();
+
+	// Remove the temporary tags file only on success, because unlike the
+	// partial Ogg file that is irrecoverable, the edited tags file
+	// contains user data, so let’s leave users a chance to recover it.
+	remove(tags_path.c_str());
+
+	return ot::st::ok;
+}
+
+/**
+ * Main loop of opustags. Read the packets from the reader, and forwards them to the writer.
+ * Transform the OpusTags packet on the fly.
+ *
+ * The writer is optional. When writer is nullptr, opustags runs in read-only mode.
+ */
+static ot::status process(ot::ogg_reader& reader, ot::ogg_writer* writer, const ot::options &opt)
+{
+	bool focused = false; /*< the stream on which we operate is defined */
+	int focused_serialno; /*< when focused, the serialno of the focused stream */
+	int absolute_page_no = -1; /*< page number in the physical stream, not logical */
+	for (;;) {
+		ot::status rc = reader.next_page();
+		if (rc == ot::st::end_of_stream)
+			break;
+		else if (rc == ot::st::bad_stream && absolute_page_no == -1)
+			return {ot::st::bad_stream, "Input is not a valid Ogg file."};
+		else if (rc != ot::st::ok)
+			return rc;
+		++absolute_page_no;
+		auto serialno = ogg_page_serialno(&reader.page);
+		auto pageno = ogg_page_pageno(&reader.page);
+		if (!focused) {
+			focused = true;
+			focused_serialno = serialno;
+		} else if (serialno != focused_serialno) {
+			/** \todo Support mixed streams. */
+			return {ot::st::error, "Muxed streams are not supported yet."};
+		}
+		if (absolute_page_no == 0) { // Identification header
+			if (!ot::is_opus_stream(reader.page))
+				return {ot::st::error, "Not an Opus stream."};
+			if (writer) {
+				rc = writer->write_page(reader.page);
+				if (rc != ot::st::ok)
+					return rc;
+			}
+		} else if (absolute_page_no == 1) { // Comment header
+			ot::opus_tags tags;
+			rc = reader.process_header_packet(
+				[&tags](ogg_packet& p) { return ot::parse_tags(p, tags); });
+			if (rc != ot::st::ok)
+				return rc;
+			if ((rc = edit_tags(tags, opt)) != ot::st::ok)
+				return rc;
+			if (writer) {
+				if (opt.edit_interactively) {
+					fflush(writer->file); // flush before calling the subprocess
+					if ((rc = edit_tags_interactively(tags, writer->path, opt.raw)) != ot::st::ok)
+						return rc;
+				}
+				auto packet = ot::render_tags(tags);
+				rc = writer->write_header_packet(serialno, pageno, packet);
+				if (rc != ot::st::ok)
+					return rc;
+			} else {
+				if ((rc = ot::print_comments(tags.comments, stdout, opt.raw)) != ot::st::ok)
+					return rc;
+				break;
+			}
+		} else {
+			if (writer && (rc = writer->write_page(reader.page)) != ot::st::ok)
+				return rc;
+		}
+	}
+	if (absolute_page_no < 1)
+		return {ot::st::error, "Expected at least 2 Ogg pages."};
+	return ot::st::ok;
+}
+
+static ot::status run_single(const ot::options& opt, const std::string& path_in, const std::optional<std::string>& path_out)
+{
+	ot::file input;
+	if (path_in == "-")
+		input = stdin;
+	else if ((input = fopen(path_in.c_str(), "re")) == nullptr)
+		return {ot::st::standard_error,
+		        "Could not open '" + path_in + "' for reading: " + strerror(errno)};
+	ot::ogg_reader reader(input.get());
+
+	/* Read-only mode. */
+	if (!path_out)
+		return process(reader, nullptr, opt);
+
+	/* Read-write mode.
+	 *
+	 * The output pointer is set to one of:
+	 *  - stdout for "-",
+	 *  - final_output.get() for special files like /dev/null,
+	 *  - temporary_output.get() for regular files.
+	 *
+	 * We use a temporary output file for the following reasons:
+	 *  1. A partial .opus output would be seen by softwares like media players, but a .part
+	 *     (for partial) won’t.
+	 *  2. If the process crashes badly, or the power cuts off, we don't want to leave a partial
+	 *     file at the final location. The temporary file is going to remain though.
+	 *  3. If we're overwriting a regular file, we'd rather avoid wiping its content before we
+	 *     even started reading the input file. That way, the original file is always preserved
+	 *     on error or crash.
+	 *  4. It is necessary for in-place editing. We can't reliably open the same file as both
+	 *     input and output.
+	 */
+
+	FILE* output = nullptr;
+	ot::partial_file temporary_output;
+	ot::file final_output;
+
+	ot::status rc = ot::st::ok;
+	struct stat output_info;
+	if (path_out == "-") {
+		output = stdout;
+	} else if (stat(path_out->c_str(), &output_info) == 0) {
+		/* The output file exists. */
+		if (!S_ISREG(output_info.st_mode)) {
+			/* Special files are opened for writing directly. */
+			if ((final_output = fopen(path_out->c_str(), "we")) == nullptr)
+				rc = {ot::st::standard_error,
+				      "Could not open '" + path_out.value() + "' for writing: " +
+				      strerror(errno)};
+			output = final_output.get();
+		} else if (opt.overwrite) {
+			rc = temporary_output.open(path_out->c_str());
+			output = temporary_output.get();
+		} else {
+			rc = {ot::st::error,
+			      "'" + path_out.value() + "' already exists. Use -y to overwrite."};
+		}
+	} else if (errno == ENOENT) {
+		rc = temporary_output.open(path_out->c_str());
+		output = temporary_output.get();
+	} else {
+		rc = {ot::st::error,
+		      "Could not identify '" + path_in + "': " + strerror(errno)};
+	}
+	if (rc != ot::st::ok)
+		return rc;
+
+	ot::ogg_writer writer(output);
+	writer.path = path_out;
+	rc = process(reader, &writer, opt);
+	if (rc == ot::st::ok)
+		rc = temporary_output.commit();
+
+	return rc;
+}
+
+ot::status ot::run(const ot::options& opt)
+{
+	if (opt.print_help) {
+		fputs(help_message, stdout);
+		return st::ok;
+	}
+
+	ot::status global_rc = st::ok;
+	for (const auto& path_in : opt.paths_in) {
+		ot::status rc = run_single(opt, path_in, opt.in_place ? path_in : opt.path_out);
+		if (rc != st::ok) {
+			global_rc = st::error;
+			if (!rc.message.empty())
+				fprintf(stderr, "%s: error: %s\n", path_in.c_str(), rc.message.c_str());
+		}
+	}
+	return global_rc;
+}

src/config.h.in

@@ -0,0 +1,7 @@
+#cmakedefine PROJECT_NAME "@PROJECT_NAME@"
+#cmakedefine PROJECT_VERSION "@PROJECT_VERSION@"
+
+#cmakedefine HAVE_ENDIAN_H @HAVE_ENDIAN_H@
+#cmakedefine HAVE_SYS_ENDIAN_H @HAVE_SYS_ENDIAN_H@
+#cmakedefine HAVE_STAT_ST_MTIM @HAVE_STAT_ST_MTIM@
+#cmakedefine HAVE_STAT_ST_MTIMESPEC @HAVE_STAT_ST_MTIMESPEC@

src/log.h

@@ -1,29 +0,0 @@
-#pragma once
-
-namespace opustags {
-
-    enum class LogLevel {
-        LOG_NORMAL = 0,
-        LOG_VERBOSE = 1,
-        LOG_DEBUG = 2,
-        LOG_DEBUG_EXTRA = 3,
-    };
-
-    class Log
-    {
-    public:
-        Log(std::ostream &out);
-
-        LogLevel level;
-
-        Log& operator<<(LogLevel lvl);
-        template<class T> Log& operator<<(const T&);
-
-    private:
-        std::ostream &out;
-    };
-
-
-    extern Log log;
-
-}

src/main.cc

@@ -1,88 +0,0 @@
-#include "actions.h"
-#include "options.h"
-#include "version.h"
-
-#include <iostream>
-#include <fstream>
-#include <cstring>
-
-static void show_usage(const bool include_help)
-{
-    static const auto usage =
-        "Usage: opustags --help\n"
-        "       opustags [OPTIONS] INPUT\n"
-        "       opustags [OPTIONS] -o OUTPUT INPUT\n";
-
-    static const auto help =
-        "Options:\n"
-        "  -h, --help              print this help\n"
-        "  -V, --version           print version\n"
-        "  -o, --output FILE       write the modified tags to this file\n"
-        "  -i, --in-place [SUFFIX] use a temporary file then replace the original file\n"
-        "  -y, --overwrite         overwrite the output file if it already exists\n"
-        "      --stream ID         select stream for the next operations\n"
-        "  -l, --list              display a pretty listing of all tags\n"
-        "      --no-color          disable colors in --list output\n"
-        "  -d, --delete FIELD      delete all the fields of a specified type\n"
-        "  -a, --add FIELD=VALUE   add a field\n"
-        "  -s, --set FIELD=VALUE   delete then add a field\n"
-        "  -D, --delete-all        delete all the fields!\n"
-        "      --full              enable full file scan\n"
-        "      --export            dump the tags to standard output for --import\n"
-        "      --import            set the tags from scratch basing on stanard input\n"
-        "  -e, --edit              spawn the $EDITOR and apply --import on the result\n";
-
-    std::cout << "opustags v" << opustags::version_short << "\n";
-    std::cout << usage;
-    if (include_help) {
-        std::cout << "\n";
-        std::cout << help;
-    }
-}
-
-static void show_version()
-{
-    std::cout << "opustags v" << opustags::version_long << "\n";
-}
-
-int main(int argc, char **argv)
-{
-    if (argc == 1) {
-        show_usage(false);
-        return EXIT_SUCCESS;
-    }
-
-    try {
-        auto options = opustags::parse_args(argc, argv);
-        if (options.show_help) {
-            show_usage(true);
-            return EXIT_SUCCESS;
-        }
-        if (options.show_version) {
-            show_version();
-            return EXIT_SUCCESS;
-        }
-
-        if (options.path_out.empty()) {
-            std::ifstream in(options.path_in);
-            opustags::ogg::Decoder dec(in);
-            list_tags(dec, options.tags_handler, options.full);
-            // TODO: report errors if user tries to edit the stream
-        } else {
-            std::ifstream in(options.path_in);
-            std::ofstream out(options.path_out);
-            opustags::ogg::Decoder dec(in);
-            opustags::ogg::Encoder enc(out);
-            edit_tags(dec, enc, options.tags_handler);
-        }
-
-    } catch (const std::exception &e) {
-        if (errno)
-            std::cerr << "fatal error: " << e.what() << " (" << strerror(errno) << ")" << std::endl;
-        else
-            std::cerr << "fatal error: " << e.what() << std::endl;
-        return EXIT_FAILURE;
-    }
-
-    return EXIT_SUCCESS;
-}

src/ogg.cc

@@ -1,308 +1,116 @@
-#include "ogg.h"
+/**
+ * \file src/ogg.c
+ * \ingroup ogg
+ *
+ * High-level interface for libogg.
+ *
+ * This module is not meant to be a complete libogg wrapper, but rather a convenient and highly
+ * specialized layer above libogg and stdio.
+ */
 
-#include <stdexcept>
-#include <fstream>
-#include <sstream>
-#include <cstring>
-#include <endian.h>
+#include <opustags.h>
 
-using namespace opustags;
+#include <errno.h>
+#include <string.h>
 
-////////////////////////////////////////////////////////////////////////////////
-// ogg::Stream
+using namespace std::literals::string_literals;
 
-ogg::Stream::Stream(int streamno)
+bool ot::is_opus_stream(const ogg_page& identification_header)
 {
-    state = ogg::BEGIN_OF_STREAM;
-    type = ogg::UNKNOWN_STREAM;
-    if (ogg_stream_init(&stream, streamno) != 0)
-        throw std::runtime_error("ogg_stream_init failed");
+	if (ogg_page_bos(&identification_header) == 0)
+		return false;
+	if (identification_header.body_len < 8)
+		return false;
+	return (memcmp(identification_header.body, "OpusHead", 8) == 0);
 }
 
-ogg::Stream::~Stream()
+ot::status ot::ogg_reader::next_page()
 {
-    ogg_stream_clear(&stream);
+	int rc;
+	while ((rc = ogg_sync_pageout(&sync, &page)) != 1) {
+		if (rc == -1)
+			return {st::bad_stream, "Unsynced data in stream."};
+		if (ogg_sync_check(&sync) != 0)
+			return {st::libogg_error, "ogg_sync_check signalled an error."};
+		if (feof(file)) {
+			if (sync.fill != sync.returned)
+				return {st::bad_stream, "Unsynced data at end of stream."};
+			return {st::end_of_stream, "End of stream was reached."};
+		}
+		char* buf = ogg_sync_buffer(&sync, 65536);
+		if (buf == nullptr)
+			return {st::libogg_error, "ogg_sync_buffer failed."};
+		size_t len = fread(buf, 1, 65536, file);
+		if (ferror(file))
+			return {st::standard_error, "fread error: "s + strerror(errno)};
+		if (ogg_sync_wrote(&sync, len) != 0)
+			return {st::libogg_error, "ogg_sync_wrote failed."};
+	}
+	return st::ok;
 }
 
-void ogg::Stream::flush_packets()
+ot::status ot::ogg_reader::process_header_packet(const std::function<status(ogg_packet&)>& f)
 {
-    ogg_packet op;
-    while (ogg_stream_packetout(&stream, &op) > 0);
+	if (ogg_page_continued(&page))
+		return {ot::st::error, "Unexpected continued header page."};
+	ogg_logical_stream stream(ogg_page_serialno(&page));
+	stream.pageno = ogg_page_pageno(&page);
+	if (ogg_stream_pagein(&stream, &page) != 0)
+		return {st::libogg_error, "ogg_stream_pagein failed."};
+	ogg_packet packet;
+	int rc = ogg_stream_packetout(&stream, &packet);
+	if (ogg_stream_check(&stream) != 0 || rc == -1)
+		return {ot::st::libogg_error, "ogg_stream_packetout failed."};
+	else if (rc == 0)
+		return {ot::st::error,
+		        "Reading header packets spanning multiple pages are not yet supported. "
+		        "Please file an issue to make your wish known."};
+	ot::status f_rc = f(packet);
+	if (f_rc != ot::st::ok)
+		return f_rc;
+	/* Ensure that there are no other segments left in the packet using the lacing state of the
+	 * stream. These are the relevant variables, as far as I understood them:
+	 *  - lacing_vals: extensible array containing the lacing values of the segments,
+	 *  - lacing_fill: number of elements in lacing_vals (not the capacity),
+	 *  - lacing_returned: index of the next segment to be processed. */
+	if (stream.lacing_returned != stream.lacing_fill)
+		return {ot::st::error, "Header page contains more than a single packet."};
+	return ot::st::ok;
 }
 
-bool ogg::Stream::page_in(ogg_page &og)
+ot::status ot::ogg_writer::write_page(const ogg_page& page)
 {
-    if (state != ogg::BEGIN_OF_STREAM && type == ogg::UNKNOWN_STREAM) {
-        state = ogg::RAW_READY;
-        return true;
-    }
-    flush_packets(); // otherwise packet_out keeps returning the same packet
-    if (ogg_stream_pagein(&stream, &og) != 0)
-        throw std::runtime_error("ogg_stream_pagein failed");
-
-    if (state == ogg::BEGIN_OF_STREAM || state == ogg::HEADER_READY) {
-        // We're expecting a header, so we parse it.
-        return handle_page();
-    } else {
-        // We're past the first two headers.
-        state = ogg::DATA_READY;
-        return true;
-    }
+	if (page.header_len < 0 || page.body_len < 0)
+		return {st::int_overflow, "Overflowing page length"};
+	auto header_len = static_cast<size_t>(page.header_len);
+	auto body_len = static_cast<size_t>(page.body_len);
+	if (fwrite(page.header, 1, header_len, file) < header_len)
+		return {st::standard_error, "fwrite error: "s + strerror(errno)};
+	if (fwrite(page.body, 1, body_len, file) < body_len)
+		return {st::standard_error, "fwrite error: "s + strerror(errno)};
+	return st::ok;
 }
 
-// Read the first packet of the page and parses it.
-bool ogg::Stream::handle_page()
+ot::status ot::ogg_writer::write_header_packet(int serialno, int pageno, ogg_packet& packet)
 {
-    ogg_packet op;
-    int rc = ogg_stream_packetpeek(&stream, &op);
-    if (rc < 0)
-        throw std::runtime_error("ogg_stream_packetout failed");
-    else if (rc == 0) // insufficient data
-        return false; // asking for a new page
-    // We've read the first packet successfully.
-    // The headers are supposed to contain only one packet, so this is enough
-    // for us. Still, we could ensure there are no other packets.
-    handle_packet(op);
-    return true;
-}
-
-void ogg::Stream::handle_packet(const ogg_packet &op)
-{
-    if (state == ogg::BEGIN_OF_STREAM)
-        parse_header(op);
-    else if (state == ogg::HEADER_READY)
-        parse_opustags(op);
-    // else shrug
-}
-
-void ogg::Stream::parse_header(const ogg_packet &op)
-{
-    if (op.bytes >= 8 && memcmp(op.packet, "OpusHead", 8) == 0)
-        type = OPUS_STREAM;
-    else
-        type = UNKNOWN_STREAM;
-    state = HEADER_READY;
-}
-
-// For reference:
-// https://tools.ietf.org/html/draft-ietf-codec-oggopus-14#section-5.2
-void ogg::Stream::parse_opustags(const ogg_packet &op)
-{
-    // This part is gonna be C-ish because I don't see how I'd do this in C++
-    // without being inefficient, both in volume of code and performance.
-    char *data = reinterpret_cast<char*>(op.packet);
-    long remaining = op.bytes;
-    if (remaining < 8 || memcmp(data, "OpusTags", 8) != 0)
-        throw std::runtime_error("expected OpusTags header");
-    data += 8;
-    remaining -= 8;
-
-    // Vendor string
-    if (remaining < 4)
-        throw std::runtime_error("no space for vendor string length");
-    uint32_t vendor_length = le32toh(*reinterpret_cast<uint32_t*>(data));
-    if (remaining - 4 < vendor_length)
-        throw std::runtime_error("invalid vendor string length");
-    tags.vendor = std::string(data + 4, vendor_length);
-    data += 4 + vendor_length;
-    remaining -= 4 + vendor_length;
-
-    // User comments count
-    if (remaining < 4)
-        throw std::runtime_error("no space for user comment list length");
-    long comment_count = le32toh(*reinterpret_cast<uint32_t*>(data));
-    data += 4;
-    remaining -= 4;
-
-    // Actual comments
-    // We iterate on a long type to prevent infinite looping when comment_count == UINT32_MAX.
-    for (long i = 0; i < comment_count; i++) {
-        if (remaining < 4)
-            throw std::runtime_error("no space for user comment length");
-        uint32_t comment_length = le32toh(*reinterpret_cast<uint32_t*>(data));
-        if (remaining - 4 < comment_length)
-            throw std::runtime_error("no space for comment contents");
-        tags.add(parse_tag(std::string(data + 4, comment_length)));
-        data += 4 + comment_length;
-        remaining -= 4 + comment_length;
-    }
-
-    // Extra data to keep if the least significant bit of the first byte is 1
-    if (remaining > 0 && (*data & 1) == 1 )
-        tags.extra = std::string(data, remaining);
-
-    state = TAGS_READY;
-}
-
-void ogg::Stream::downgrade()
-{
-    type = ogg::UNKNOWN_STREAM;
-    if (state != ogg::BEGIN_OF_STREAM && state != ogg::END_OF_STREAM)
-        state = RAW_READY;
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// ogg::Decoder
-
-ogg::Decoder::Decoder(std::istream &in)
-    : input(in)
-{
-    if (!in)
-        throw std::runtime_error("invalid stream to decode");
-    input.exceptions(std::ifstream::badbit);
-    ogg_sync_init(&sync);
-}
-
-ogg::Decoder::~Decoder()
-{
-    ogg_sync_clear(&sync);
-}
-
-std::shared_ptr<ogg::Stream> ogg::Decoder::read_page()
-{
-    while (page_out()) {
-        int streamno = ogg_page_serialno(&current_page);
-        auto i = streams.find(streamno);
-        if (i == streams.end()) {
-            // we could check the page number to detect new streams (pageno = 0)
-            auto s = std::make_shared<Stream>(streamno);
-            i = streams.emplace(streamno, s).first;
-        }
-        if (i->second->page_in(current_page))
-            return i->second;
-    }
-    return nullptr; // end of stream
-}
-
-// Read the next page and return true on success, false on end of stream.
-bool ogg::Decoder::page_out()
-{
-    int rc;
-    for (;;) {
-        rc = ogg_sync_pageout(&sync, &current_page);
-        if (rc < 0) {
-            throw std::runtime_error("ogg_sync_pageout failed");
-        } else if (rc == 1) {
-            break; // page complete
-        } else if (!buff()) {
-            // more data required but end of file reached
-            // TODO check sync.unsynced flag in case we've got an incomplete page
-            return false;
-        }
-    }
-    return true;
-}
-
-// Read data from the stream into the sync's buffer.
-bool ogg::Decoder::buff()
-{
-    if (input.eof())
-        return false;
-    char *buf = ogg_sync_buffer(&sync, 65536);
-    if (buf == nullptr)
-        throw std::runtime_error("ogg_sync_buffer failed");
-    input.read(buf, 65536);
-    ogg_sync_wrote(&sync, input.gcount());
-    return true;
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// ogg::Encoder
-
-ogg::Encoder::Encoder(std::ostream &out)
-    : output(out)
-{
-    if (!output)
-        throw std::runtime_error("invalid stream to decode");
-    output.exceptions(std::ifstream::badbit);
-}
-
-ogg::Stream& ogg::Encoder::get_stream(int streamno)
-{
-    auto i = streams.find(streamno);
-    if (i == streams.end()) {
-        auto s = std::make_shared<Stream>(streamno);
-        i = streams.emplace(streamno, s).first;
-    }
-    return *(i->second);
-}
-
-void ogg::Encoder::forward(ogg::Stream &in)
-{
-    ogg::Stream *out = &get_stream(in.stream.serialno);
-    forward_stream(in, *out);
-    flush_stream(*out);
-}
-
-void ogg::Encoder::forward_stream(ogg::Stream &in, ogg::Stream &out)
-{
-    int rc;
-    ogg_packet op;
-    for (;;) {
-        rc = ogg_stream_packetout(&in.stream, &op);
-        if (rc < 0) {
-            throw std::runtime_error("ogg_stream_packetout failed");
-        } else if (rc == 0) {
-            break;
-        } else {
-            if (ogg_stream_packetin(&out.stream, &op) != 0)
-                throw std::runtime_error("ogg_stream_packetin failed");
-        }
-    }
-}
-
-void ogg::Encoder::flush_stream(ogg::Stream &out)
-{
-    ogg_page og;
-    if (ogg_stream_flush(&out.stream, &og))
-            write_raw_page(og);
-}
-
-void ogg::Encoder::write_raw_page(const ogg_page &og)
-{
-    output.write(reinterpret_cast<const char*>(og.header), og.header_len);
-    output.write(reinterpret_cast<const char*>(og.body), og.body_len);
-}
-
-void ogg::Encoder::write_tags(int streamno, const Tags &tags)
-{
-    ogg_packet op;
-    op.b_o_s = 0;
-    op.e_o_s = 0;
-    op.granulepos = 0;
-    op.packetno = 1; // checked on a file from ffmpeg
-
-    std::string data = render_opustags(tags);
-    op.bytes = data.size();
-    op.packet = reinterpret_cast<unsigned char*>(const_cast<char*>(data.data()));
-
-    std::shared_ptr<ogg::Stream> s = streams.at(streamno); // assume it exists
-    if (ogg_stream_packetin(&s->stream, &op) != 0)
-        throw std::runtime_error("ogg_stream_packetin failed");
-    flush_stream(*s);
-}
-
-std::string ogg::Encoder::render_opustags(const Tags &tags)
-{
-    std::stringbuf s;
-    uint32_t length;
-    s.sputn("OpusTags", 8);
-    length = htole32(tags.vendor.size());
-    s.sputn(reinterpret_cast<char*>(&length), 4);
-    s.sputn(tags.vendor.data(), tags.vendor.size());
-
-    auto assocs = tags.get_all();
-    length = htole32(assocs.size());
-    s.sputn(reinterpret_cast<char*>(&length), 4);
-
-    for (const auto assoc : assocs) {
-        length = htole32(assoc.key.size() + 1 + assoc.value.size());
-        s.sputn(reinterpret_cast<char*>(&length), 4);
-        s.sputn(assoc.key.data(), assoc.key.size());
-        s.sputc('=');
-        s.sputn(assoc.value.data(), assoc.value.size());
-    }
-
-    s.sputn(tags.extra.data(), tags.extra.size());
-    return s.str();
+	ogg_logical_stream stream(serialno);
+	stream.b_o_s = (pageno != 0);
+	stream.pageno = pageno;
+	if (ogg_stream_packetin(&stream, &packet) != 0)
+		return {ot::st::libogg_error, "ogg_stream_packetin failed"};
+	ogg_page page;
+	if (ogg_stream_flush(&stream, &page) != 0) {
+		ot::status rc = write_page(page);
+		if (rc != ot::st::ok)
+			return rc;
+	} else {
+		return {ot::st::libogg_error, "ogg_stream_flush failed"};
+	}
+	if (ogg_stream_flush(&stream, &page) != 0)
+		return {ot::st::error,
+		        "Writing header packets spanning multiple pages are not yet supported. "
+		        "Please file an issue to make your wish known."};
+	if (ogg_stream_check(&stream) != 0)
+		return {st::libogg_error, "ogg_stream_check failed"};
+	return ot::st::ok;
 }

src/ogg.h

@@ -1,129 +0,0 @@
-#pragma once
-
-#include "tags.h"
-
-#include <iostream>
-#include <map>
-#include <memory>
-#include <ogg/ogg.h>
-
-namespace opustags {
-namespace ogg
-{
-    enum StreamState {
-        BEGIN_OF_STREAM,
-        HEADER_READY,
-        TAGS_READY,
-        DATA_READY,
-        RAW_READY,
-        END_OF_STREAM,
-        // Meaning of these states below, in Stream.
-    };
-
-    enum StreamType {
-        UNKNOWN_STREAM = 0,
-        OPUS_STREAM,
-    };
-
-    // An Ogg file may contain many logical bitstreams, and among them, many
-    // Opus streams. This class represents one stream, whether it is Opus or
-    // not.
-    struct Stream
-    {
-        Stream(int streamno);
-        Stream(const Stream&) = delete;
-        ~Stream();
-
-        // Called by Decoder once a page was read.
-        // Returns true if it's ready, false if it expects more data.
-        // In the latter case, Decoder::read_page will keep reading.
-        bool page_in(ogg_page&);
-
-        // Make the stream behave as if it were unknown.
-        // As a consequence, no more effort would be made in extracting data.
-        void downgrade();
-
-        StreamState state;
-        StreamType type;
-        Tags tags;
-
-        // Here are the meanings of the state variable:
-        //   BEGIN_OF_STREAM: the stream was just initialized,
-        //   HEADER_READY: the header (first packet) was found,
-        //   TAGS_READY: the tags are parsed and complete,
-        //   DATA_READY: we've read a data page whose meaning is no concern to us,
-        //   RAW_READY: we don't even know what kind of stream that is, so don't alter it,
-        //   END_OF_STREAM: no more thing to read, not even the current page.
-
-        // From the state, we decide what to do with the Decoder's current_page.
-        // The difference between DATA_READY and RAW_DATA is that the former
-        // might require a reencoding of the current page. For example, if the
-        // tags grow and span over two pages, all the following pages are gonna
-        // need a new sequence number.
-
-        // For an Opus stream, the sequence will be:
-        //   BEGIN_OF_STREAM → HEADER_READY → TAGS_READY → DATA_READY* → END_OF_STREAM
-        // For an unknown stream:
-        //   BEGIN_OF_STREAM → HEADER_READY → RAW_READY* → END_OF_STREAM
-
-        ogg_stream_state stream;
-
-    private:
-        void flush_packets();
-        bool handle_page();
-        void handle_packet(const ogg_packet&);
-        void parse_header(const ogg_packet&);
-        void parse_opustags(const ogg_packet&);
-    };
-
-    struct Decoder
-    {
-        Decoder(std::istream&);
-        Decoder(const Decoder&) = delete;
-        ~Decoder();
-
-        // Read a page, dispatch it, and return the stream it belongs to.
-        // The read page is given to Stream::page_in before this function
-        // returns.
-        // After the end of the file is reached, it returns NULL.
-        std::shared_ptr<Stream> read_page();
-
-        std::istream &input;
-
-        ogg_sync_state sync;
-        ogg_page current_page;
-        std::map<int, std::shared_ptr<Stream>> streams;
-
-    private:
-        bool page_out();
-        bool buff();
-    };
-
-    struct Encoder
-    {
-        Encoder(std::ostream&);
-
-        // Copy the input stream's current page.
-        void forward(Stream &in);
-
-        // Write the page without even ensuring its page number is correct.
-        // It would be an efficient way to copy a stream identically, and also
-        // needed for write_page.
-        void write_raw_page(const ogg_page&);
-
-        void write_tags(int streamno, const Tags&);
-
-        std::ostream &output;
-
-        // We're gonna need some ogg_stream_state for adjusting the page
-        // numbers and splitting large packets as it's gotta be done.
-        std::map<int, std::shared_ptr<Stream>> streams;
-
-    private:
-        Stream& get_stream(int streamno);
-        void forward_stream(Stream &in, Stream &out);
-        void flush_stream(Stream &out);
-        std::string render_opustags(const Tags &tags);
-    };
-}
-}

src/options.cc

@@ -1,199 +0,0 @@
-#include "options.h"
-
-#include "tags_handlers/insertion_tags_handler.h"
-#include "tags_handlers/modification_tags_handler.h"
-#include "tags_handlers/external_edit_tags_handler.h"
-#include "tags_handlers/export_tags_handler.h"
-#include "tags_handlers/import_tags_handler.h"
-#include "tags_handlers/listing_tags_handler.h"
-#include "tags_handlers/removal_tags_handler.h"
-
-#include <getopt.h>
-#include <regex>
-#include <sstream>
-
-using namespace opustags;
-
-ArgumentError::ArgumentError(const std::string &message)
-    : std::runtime_error(message.c_str())
-{
-}
-
-Options::Options() :
-    show_help(false),
-    show_version(false),
-    overwrite(false),
-    full(false),
-    in_place(false)
-{
-}
-
-Options opustags::parse_args(const int argc, char **argv)
-{
-    static const auto short_def = "hVeo:i::yd:a:s:Dl";
-
-    static const option long_def[] = {
-        {"help",        no_argument,        0, 'h'},
-        {"version",     no_argument,        0, 'V'},
-        {"full",        no_argument,        0, 0},
-        {"output",      required_argument,  0, 'o'},
-        {"in-place",    optional_argument,  0, 'i'},
-        {"overwrite",   no_argument,        0, 'y'},
-        {"delete",      required_argument,  0, 'd'},
-        {"add",         required_argument,  0, 'a'},
-        {"stream",      required_argument,  0, 0},
-        {"set",         required_argument,  0, 's'},
-        {"list",        no_argument,        0, 'l'},
-        {"delete-all",  no_argument,        0, 'D'},
-        {"edit",        no_argument,        0, 'e'},
-        {"import",      no_argument,        0, 0},
-        {"export",      no_argument,        0, 0},
-
-        // TODO: parse no-colors
-
-        {nullptr, 0, 0, 0}
-    };
-
-    // TODO: use --list as default switch
-
-    Options options;
-
-    std::vector<int> current_streamnos {StreamTagsHandler::ALL_STREAMS};
-    int option_index;
-    char c;
-    optind = 0;
-
-    while ((c = getopt_long(
-        argc, argv, short_def, long_def, &option_index)) != -1) {
-
-        const std::string arg(optarg == nullptr ? "" : optarg);
-
-        switch (c) {
-            case 'h':
-                options.show_help = true;
-                break;
-
-            case 'V':
-                options.show_version = true;
-                break;
-
-            case 'o':
-                if (arg.empty())
-                    throw ArgumentError("Output path cannot be empty");
-                options.path_out = arg;
-                break;
-
-            case 'i':
-                // TODO: shouldn't we generate random file name here to which
-                // we apply the arg, rather than use the arg as a whole?
-                options.path_out = arg.empty() ? ".otmp" : arg;
-                options.in_place = true;
-                break;
-
-            case 'y':
-                options.overwrite = true;
-                break;
-
-            case 'd':
-                if (arg.find('=') != std::string::npos)
-                    throw ArgumentError("Invalid field: '" + arg + "'");
-                for (const auto streamno : current_streamnos) {
-                    options.tags_handler.add_handler(
-                        std::make_shared<RemovalTagsHandler>(streamno, arg));
-                }
-                break;
-
-            case 'a':
-            case 's':
-            {
-                std::smatch match;
-                std::regex regex("^(\\w+)=(.*)$");
-                if (!std::regex_match(arg, match, regex))
-                    throw ArgumentError("Invalid field: '" + arg + "'");
-                for (const auto streamno : current_streamnos) {
-                    if (c == 's') {
-                        options.tags_handler.add_handler(
-                            std::make_shared<ModificationTagsHandler>(
-                                streamno, match[1], match[2]));
-                    } else {
-                        options.tags_handler.add_handler(
-                            std::make_shared<InsertionTagsHandler>(
-                                streamno, match[1], match[2]));
-                    }
-                }
-                break;
-            }
-
-            case 'l':
-                for (const auto streamno : current_streamnos) {
-                    options.tags_handler.add_handler(
-                        std::make_shared<ListingTagsHandler>(
-                            streamno, std::cout));
-                }
-                break;
-
-            case 'e':
-                options.tags_handler.add_handler(
-                    std::make_shared<ExternalEditTagsHandler>());
-                break;
-
-            case 'D':
-                for (const auto streamno : current_streamnos) {
-                    options.tags_handler.add_handler(
-                        std::make_shared<RemovalTagsHandler>(streamno));
-                }
-                break;
-
-            case 0:
-            {
-                std::string long_arg = long_def[option_index].name;
-                if (long_arg == "stream") {
-                    int i;
-                    current_streamnos.clear();
-                    std::stringstream ss(optarg);
-                    while (ss >> i) {
-                        current_streamnos.push_back(i);
-                        if (ss.peek() == ',')
-                            ss.ignore();
-                    }
-                }
-                else if (long_arg == "full")
-                    options.full = true;
-                else if (long_arg == "export")
-                    options.tags_handler.add_handler(
-                        std::make_shared<ExportTagsHandler>(std::cout));
-                else if (long_arg == "import")
-                    options.tags_handler.add_handler(
-                        std::make_shared<ImportTagsHandler>(std::cin));
-                break;
-            }
-
-            default:
-                throw ArgumentError("Invalid flag");
-        }
-    }
-
-    std::vector<std::string> stray;
-    while (optind < argc)
-        stray.push_back(argv[optind++]);
-
-    if (!options.show_help && !options.show_version) {
-        if (stray.empty())
-            throw ArgumentError("Missing input path");
-
-        options.path_in = stray.at(0);
-        if (options.path_in.empty())
-            throw ArgumentError("Input path cannot be empty");
-
-        if (stray.size() > 1)
-            throw ArgumentError("Extra argument: " + stray.at(1));
-
-        if (options.path_out.empty()) {
-            options.tags_handler.add_handler(
-                std::make_shared<ListingTagsHandler>(
-                    StreamTagsHandler::ALL_STREAMS, std::cout));
-        }
-    }
-
-    return options;
-}

src/options.h

@@ -1,33 +0,0 @@
-#pragma once
-
-#include "tags_handlers/composite_tags_handler.h"
-
-#include <stdexcept>
-#include <map>
-#include <vector>
-
-namespace opustags
-{
-    struct Options final
-    {
-        Options();
-
-        bool show_help;
-        bool show_version;
-        bool overwrite;
-        bool full;
-
-        bool in_place;
-        std::string path_in;
-        std::string path_out;
-
-        CompositeTagsHandler tags_handler;
-    };
-
-    struct ArgumentError : std::runtime_error
-    {
-        ArgumentError(const std::string &message);
-    };
-
-    Options parse_args(const int argc, char **argv);
-}

src/opus.cc

@@ -0,0 +1,127 @@
+/**
+ * \file src/opus.cc
+ * \ingroup opus
+ *
+ * The way Opus is encapsulated into an Ogg stream, and the content of the packets we're dealing
+ * with here is defined by [RFC 7584](https://tools.ietf.org/html/rfc7845.html).
+ *
+ * Section 3 "Packet Organization" is critical for us:
+ *
+ * - The first page contains exactly 1 packet, the OpusHead, and it contains it entirely.
+ * - The second page begins the OpusTags packet, which may span several pages.
+ * - The OpusTags packet must finish the page on which it completes.
+ *
+ * The structure of the OpusTags packet is defined in section 5.2 "Comment Header" of the RFC.
+ *
+ * OpusTags is similar to [Vorbis Comment](https://www.xiph.org/vorbis/doc/v-comment.html), which
+ * gives us some context, but let's stick to the RFC for the technical details.
+ *
+ * \todo Validate that the vendor string and comments are valid UTF-8.
+ * \todo Validate that field names are ASCII: 0x20 through 0x7D, 0x3D ('=') excluded.
+ *
+ */
+
+#include <opustags.h>
+
+#include <string.h>
+
+#ifdef HAVE_ENDIAN_H
+#  include <endian.h>
+#endif
+
+#ifdef HAVE_SYS_ENDIAN_H
+#  include <sys/endian.h>
+#endif
+
+#ifdef __APPLE__
+#include <libkern/OSByteOrder.h>
+#define htole32(x) OSSwapHostToLittleInt32(x)
+#define le32toh(x) OSSwapLittleToHostInt32(x)
+#endif
+
+ot::status ot::parse_tags(const ogg_packet& packet, opus_tags& tags)
+{
+	if (packet.bytes < 0)
+		return {st::int_overflow, "Overflowing comment header length"};
+	size_t size = static_cast<size_t>(packet.bytes);
+	const char* data = reinterpret_cast<char*>(packet.packet);
+	size_t pos = 0;
+	opus_tags my_tags;
+
+	// Magic number
+	if (8 > size)
+		return {st::cut_magic_number, "Comment header too short for the magic number"};
+	if (memcmp(data, "OpusTags", 8) != 0)
+		return {st::bad_magic_number, "Comment header did not start with OpusTags"};
+
+	// Vendor
+	pos = 8;
+	if (pos + 4 > size)
+		return {st::cut_vendor_length,
+		        "Vendor string length did not fit the comment header"};
+	size_t vendor_length = le32toh(*((uint32_t*) (data + pos)));
+	if (pos + 4 + vendor_length > size)
+		return {st::cut_vendor_data, "Vendor string did not fit the comment header"};
+	my_tags.vendor = std::string(data + pos + 4, vendor_length);
+	pos += 4 + my_tags.vendor.size();
+
+	// Comment count
+	if (pos + 4 > size)
+		return {st::cut_comment_count, "Comment count did not fit the comment header"};
+	uint32_t count = le32toh(*((uint32_t*) (data + pos)));
+	pos += 4;
+
+	// Comments' data
+	for (uint32_t i = 0; i < count; ++i) {
+		if (pos + 4 > size)
+			return {st::cut_comment_length,
+			        "Comment length did not fit the comment header"};
+		uint32_t comment_length = le32toh(*((uint32_t*) (data + pos)));
+		if (pos + 4 + comment_length > size)
+			return {st::cut_comment_data,
+			        "Comment string did not fit the comment header"};
+		const char *comment_value = data + pos + 4;
+		my_tags.comments.emplace_back(comment_value, comment_length);
+		pos += 4 + comment_length;
+	}
+
+	// Extra data
+	my_tags.extra_data = std::string(data + pos, size - pos);
+
+	tags = std::move(my_tags);
+	return st::ok;
+}
+
+ot::dynamic_ogg_packet ot::render_tags(const opus_tags& tags)
+{
+	size_t size = 8 + 4 + tags.vendor.size() + 4;
+	for (const std::string& comment : tags.comments)
+		size += 4 + comment.size();
+	size += tags.extra_data.size();
+
+	dynamic_ogg_packet op(size);
+	op.b_o_s = 0;
+	op.e_o_s = 0;
+	op.granulepos = 0;
+	op.packetno = 1;
+
+	unsigned char* data = op.packet;
+	uint32_t n;
+	memcpy(data, "OpusTags", 8);
+	n = htole32(tags.vendor.size());
+	memcpy(data+8, &n, 4);
+	memcpy(data+12, tags.vendor.data(), tags.vendor.size());
+	data += 12 + tags.vendor.size();
+	n = htole32(tags.comments.size());
+	memcpy(data, &n, 4);
+	data += 4;
+	for (const std::string& comment : tags.comments) {
+		n = htole32(comment.size());
+		memcpy(data, &n, 4);
+		memcpy(data+4, comment.data(), comment.size());
+		data += 4 + comment.size();
+	}
+	memcpy(data, tags.extra_data.data(), tags.extra_data.size());
+
+	return op;
+}

src/opustags.cc

@@ -0,0 +1,27 @@
+/**
+ * \file src/opustags.cc
+ * \brief Main function for opustags.
+ *
+ * See opustags.h for the program's documentation.
+ */
+
+#include <opustags.h>
+
+#include <locale.h>
+
+/**
+ * Main function of the opustags binary.
+ *
+ * Does practically nothing but call the cli module.
+ */
+int main(int argc, char** argv) {
+	setlocale(LC_ALL, "");
+	ot::options opt;
+	ot::status rc = ot::parse_options(argc, argv, opt, stdin);
+	if (rc == ot::st::ok)
+		rc = ot::run(opt);
+	else if (!rc.message.empty())
+		fprintf(stderr, "error: %s\n", rc.message.c_str());
+
+	return rc == ot::st::ok ? EXIT_SUCCESS : EXIT_FAILURE;
+}

src/opustags.h

@@ -0,0 +1,516 @@
+/**
+ * \file src/opustags.h
+ *
+ * Welcome to opustags!
+ *
+ * Let's have a quick tour around. The project is split into the following modules:
+ *
+ * - The system module provides a few generic tools for interating with the system.
+ * - The ogg module reads and writes Ogg files, letting you manipulate Ogg pages and packets.
+ * - The opus module parses the contents of Ogg packets according to the Opus specifications.
+ * - The cli module implements the main logic of the program.
+ * - The opustags module contains the main function, which is a simple wrapper around cli.
+ *
+ * Each module is implemented in its eponymous .cc file. Their interfaces are all defined and
+ * documented together in this header file. Look into the .cc files for implementation-specific
+ * details.
+ *
+ * To understand how this program works, you need to know what an Ogg files is made of, in
+ * particular the streams, pages, and packets. You hardly need any knowledge of the actual Opus
+ * audio codec, but need the RFC 7845 "Ogg Encapsulation for the Opus Audio Codec" that defines the
+ * format of the header packets that are essential to opustags.
+ *
+ */
+
+#pragma once
+
+#include <config.h>
+
+#include <iconv.h>
+#include <ogg/ogg.h>
+#include <stdio.h>
+#include <time.h>
+
+#include <functional>
+#include <list>
+#include <memory>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace ot {
+
+/**
+ * Possible return status code, ranging from errors to special statuses. They are usually
+ * accompanied with a message with the #status structure.
+ *
+ * Functions that return non-ok status codes to signal special conditions like #end_of_stream should
+ * have it explictly mentionned in their documentation. By default, a non-ok status should be
+ * handled like an error.
+ *
+ * Error codes do not need to be ultra specific, and are mainly used to report special conditions to
+ * the caller function. Ultimately, only the error message in the #status is shown to the user.
+ *
+ * The cut error family means that the end of packet was reached when attempting to read the
+ * overflowing value. For example, cut_comment_count means that after reading the vendor string,
+ * less than 4 bytes were left in the packet.
+ */
+enum class st {
+	/* Generic */
+	ok,
+	error,
+	standard_error, /**< Error raised by the C standard library. */
+	int_overflow,
+	cancel,
+	/* System */
+	badly_encoded,
+	child_process_failed,
+	/* Ogg */
+	bad_stream,
+	end_of_stream,
+	libogg_error,
+	/* Opus */
+	bad_magic_number,
+	cut_magic_number,
+	cut_vendor_length,
+	cut_vendor_data,
+	cut_comment_count,
+	cut_comment_length,
+	cut_comment_data,
+	/* CLI */
+	bad_arguments,
+};
+
+/**
+ * Wraps a status code with an optional message. It is implictly converted to and from a
+ * #status_code.
+ *
+ * All the statuses except #st::ok should be accompanied with a relevant error message, in case it
+ * propagates back to the main function and is shown to the user.
+ *
+ * \todo Instead of being returned, it could be thrown. Most of the error handling code just let the
+ *       status bubble. When we're confident about RAII, we're good to go. When we migrate, let's
+ *       start from main and adapt the functions top-down.
+ */
+struct status {
+	status(st code = st::ok) : code(code) {}
+	template<class T> status(st code, T&& message) : code(code), message(message) {}
+	operator st() { return code; }
+	st code;
+	std::string message;
+};
+
+/***********************************************************************************************//**
+ * \defgroup system System
+ * \{
+ */
+
+/**
+ * Smart auto-closing FILE* handle.
+ *
+ * It implictly converts from an already opened FILE*.
+ */
+struct file : std::unique_ptr<FILE, decltype(&fclose)> {
+	file(FILE* f = nullptr) : std::unique_ptr<FILE, decltype(&fclose)>(f, &fclose) {}
+};
+
+/**
+ * A partial file is a temporary file created to store the result of something. When it is complete,
+ * it is moved to a final destination. Open it with #open and then you can either #commit it to save
+ * it to its destination, or you can #abort to delete the temporary file. When the #partial_file
+ * object is destroyed, it deletes the currently opened temporary file, if any.
+ */
+class partial_file {
+public:
+	~partial_file() { abort(); }
+	/**
+	 * Open a temporary file meant to be moved to the specified destination file path. The
+	 * temporary file is created in the same directory as its destination in order to make the
+	 * final move operation instant.
+	 */
+	ot::status open(const char* destination);
+	/** Close then move the partial file to its final location. */
+	ot::status commit();
+	/** Delete the temporary file. */
+	void abort();
+	/** Get the underlying FILE* handle. */
+	FILE* get() { return file.get(); }
+	/** Get the name of the temporary file. */
+	const char* name() const { return file == nullptr ? nullptr : temporary_name.c_str(); }
+private:
+	std::string temporary_name;
+	std::string final_name;
+	ot::file file;
+};
+
+/** C++ wrapper for iconv. */
+class encoding_converter {
+public:
+	/**
+	 * Allocate the iconv conversion state, initializing the given source and destination
+	 * character encodings. If it's okay to have some information lost, make sure `to` ends with
+	 * "//TRANSLIT", otherwise the conversion will fail when a character cannot be represented
+	 * in the target encoding. See the documentation of iconv_open for details.
+	 */
+	encoding_converter(const char* from, const char* to);
+	~encoding_converter();
+	/**
+	 * Convert text using iconv. If the input sequence is invalid, return #st::badly_encoded and
+	 * abort the processing, leaving out in an undefined state.
+	 */
+	status operator()(std::string_view in, std::string& out);
+private:
+	iconv_t cd; /**< conversion descriptor */
+};
+
+/** Escape a string so that a POSIX shell interprets it as a single argument. */
+std::string shell_escape(std::string_view word);
+
+/**
+ * Execute the editor process specified in editor. Wait for the process to exit and
+ * return st::ok on success, or st::child_process_failed if it did not exit with 0.
+ *
+ * editor is passed unescaped to the shell, and may contain CLI options.
+ * path is the name of the file to edit, which will be passed as the last argument to editor.
+ */
+ot::status run_editor(std::string_view editor, std::string_view path);
+
+/**
+ * Return the specified path’s mtime, i.e. the last data modification
+ * timestamp.
+ */
+ot::status get_file_timestamp(const char* path, timespec& mtime);
+
+/** \} */
+
+/***********************************************************************************************//**
+ * \defgroup ogg Ogg
+ * \{
+ */
+
+/**
+ * RAII-aware wrapper around libogg's ogg_stream_state. Though it handles automatic destruction, it
+ * does not prevent copying or implement move semantics correctly, so it's your responsibility to
+ * ensure these operations don't happen.
+ */
+struct ogg_logical_stream : ogg_stream_state {
+	ogg_logical_stream(int serialno) {
+		if (ogg_stream_init(this, serialno) != 0)
+			throw std::bad_alloc();
+	}
+	~ogg_logical_stream() {
+		ogg_stream_clear(this);
+	}
+};
+
+/**
+ * Identify the codec of a logical stream based on the first bytes of the first packet of the first
+ * page. For Opus, the first 8 bytes must be OpusHead. Any other signature is assumed to be another
+ * codec.
+ */
+bool is_opus_stream(const ogg_page& identification_header);
+
+/**
+ * Ogg reader, combining a FILE input, an ogg_sync_state reading the pages.
+ *
+ * Call #read_page repeatedly until #status::end_of_stream to consume the stream, and use #page to
+ * check its content.
+ *
+ * \todo This class could be made more intuitive if it acted like an iterator, to be used like
+ *       `for (ogg_page& page : ogg_reader(input))`, but the prerequisite for this is the ability to
+ *       throw an exception on error.
+ */
+struct ogg_reader {
+	/**
+	 * Initialize the reader with the given input file handle. The caller is responsible for
+	 * keeping the file handle alive, and to close it.
+	 */
+	ogg_reader(FILE* input) : file(input) { ogg_sync_init(&sync); }
+	/**
+	 * Clear all the internal memory allocated by libogg for the sync and stream state. The
+	 * page and the packet are owned by these states, so nothing to do with them.
+	 *
+	 * The input file is not closed.
+	 */
+	~ogg_reader() { ogg_sync_clear(&sync); }
+	/**
+	 * Read the next page from the input file. The result, provided the status is #status::ok,
+	 * is made available in the #page field, is owned by the Ogg reader, and is valid until the
+	 * next call to #read_page.
+	 *
+	 * After the last page was read, return #status::end_of_stream.
+	 */
+	status next_page();
+	/**
+	 * Read the single packet contained in the last page read, assuming it's a header page, and
+	 * call the function f on it. This function has no side effect, and calling it twice on the
+	 * same page will read the same packet again.
+	 *
+	 * It is currently limited to packets that fit on a single page, and should be later
+	 * extended to support packets spanning multiple pages.
+	 */
+	status process_header_packet(const std::function<status(ogg_packet&)>& f);
+	/**
+	 * Current page from the sync state.
+	 *
+	 * Its memory is managed by libogg, inside the sync state, and is valid until the next call
+	 * to ogg_sync_pageout, wrapped by #read_page.
+	 */
+	ogg_page page;
+	/**
+	 * The file is our source of binary data. It is not integrated to libogg, so we need to
+	 * handle it ourselves.
+	 *
+	 * The file is not owned by the ogg_reader instance.
+	 */
+	FILE* file;
+	/**
+	 * The sync layer gets binary data and yields a sequence of pages.
+	 *
+	 * A page contains packets that we can extract using the #stream state, but we only do that
+	 * for the headers. Once we got the OpusHead and OpusTags packets, all the following pages
+	 * are simply forwarded to the Ogg writer.
+	 */
+	ogg_sync_state sync;
+};
+
+/**
+ * An Ogg writer lets you write ogg_page objets to an output file, and assemble packets into pages.
+ *
+ * Its packet writing facility is limited to writing single-page header packets, because that's all
+ * we need for opustags.
+ */
+struct ogg_writer {
+	/**
+	 * Initialize the writer with the given output file handle. The caller is responsible for
+	 * keeping the file handle alive, and to close it.
+	 */
+	explicit ogg_writer(FILE* output) : file(output) {}
+	/**
+	 * Write a whole Ogg page into the output stream.
+	 *
+	 * This is a basic I/O operation and does not even require libogg, or the stream.
+	 */
+	status write_page(const ogg_page& page);
+	/**
+	 * Write a header packet and flush the page. Header packets are always placed alone on their
+	 * pages.
+	 */
+	status write_header_packet(int serialno, int pageno, ogg_packet& packet);
+	/**
+	 * Output file. It should be opened in binary mode. We use it to write whole pages,
+	 * represented as a block of data and a length.
+	 */
+	FILE* file;
+	/**
+	 * Path to the output file.
+	 */
+	std::optional<std::string> path;
+};
+
+/**
+ * Ogg packet with dynamically allocated data.
+ *
+ * Provides a wrapper around libogg's ogg_packet with RAII.
+ */
+struct dynamic_ogg_packet : ogg_packet {
+	/** Construct an ogg_packet of the given size. */
+	explicit dynamic_ogg_packet(size_t size) {
+		bytes = size;
+		data = std::make_unique<unsigned char[]>(size);
+		packet = data.get();
+	}
+private:
+	/** Owning reference to the data. Use the packet field from ogg_packet instead. */
+	std::unique_ptr<unsigned char[]> data;
+};
+
+/** \} */
+
+/***********************************************************************************************//**
+ * \defgroup opus Opus
+ * \{
+ */
+
+/**
+ * Faithfully represent *all* the data in an OpusTags packet, exactly as they will be written in the
+ * final stream, disregarding the current system locale or anything else.
+ *
+ * The vendor and comment strings are expected to contain valid UTF-8, but we should keep their
+ * values intact even if the string is not UTF-8 clean, or encoded in any other way.
+ */
+struct opus_tags {
+	/**
+	 * OpusTags packets begin with a vendor string, meant to identify the implementation of the
+	 * encoder. It is expected to be an arbitrary UTF-8 string.
+	 */
+	std::string vendor;
+	/**
+	 * Comments are strings in the NAME=Value format. A comment may also be called a field, or a
+	 * tag.
+	 *
+	 * The field name in vorbis comments is usually case-insensitive and ASCII, while the value
+	 * can be any valid UTF-8 string. The specification is not too clear for Opus, but let's
+	 * assume it's the same.
+	 */
+	std::list<std::string> comments;
+	/**
+	 * According to RFC 7845:
+	 * > Immediately following the user comment list, the comment header MAY contain
+	 * > zero-padding or other binary data that is not specified here.
+	 *
+	 * The first byte is supposed to indicate whether this data should be kept or not, but let's
+	 * assume it's here for a reason and always keep it. Better safe than sorry.
+	 *
+	 * In the future, we could add options to manipulate this data: view it, edit it, truncate
+	 * it if it's marked as padding, truncate it unconditionally.
+	 */
+	std::string extra_data;
+};
+
+/**
+ * Read the given OpusTags packet and extract its content into an opus_tags object.
+ *
+ * On error, the tags object is left unchanged.
+ */
+status parse_tags(const ogg_packet& packet, opus_tags& tags);
+
+/**
+ * Serialize an #opus_tags object into an OpusTags Ogg packet.
+ */
+dynamic_ogg_packet render_tags(const opus_tags& tags);
+
+/** \} */
+
+/***********************************************************************************************//**
+ * \defgroup cli Command-Line Interface
+ * \{
+ */
+
+/**
+ * Structured representation of the command-line arguments to opustags.
+ */
+struct options {
+	/**
+	 * When true, opustags prints a detailed help and exits. All the other options are ignored.
+	 *
+	 * Option: --help
+	 */
+	bool print_help = false;
+	/**
+	 * Paths to the input files. The special string "-" means stdin.
+	 *
+	 * At least one input file must be given. If `--in-place` is used,
+	 * more than one may be given.
+	 */
+	std::vector<std::string> paths_in;
+	/**
+	 * Optional path to output file. The special string "-" means stdout. For in-place
+	 * editing, the input file name is used. If no output file name is supplied, and
+	 * --in-place is not used, opustags runs in read-only mode.
+	 *
+	 * Options: --output, --in-place
+	 */
+	std::optional<std::string> path_out;
+	/**
+	 * By default, opustags won't overwrite the output file if it already exists. This can be
+	 * forced with --overwrite. It is also enabled by --in-place.
+	 *
+	 * Options: --overwrite, --in-place
+	 */
+	bool overwrite = false;
+	/**
+	 * Process files in-place.
+	 *
+	 * Options: --in-place
+	 */
+	bool in_place = false;
+	/**
+	 * Spawn EDITOR to edit tags interactively.
+	 *
+	 * stdin and stdout must be left free for the editor, so paths_in and
+	 * path_out can’t take `-`, and --set-all is not supported.
+	 *
+	 * Option: --edit
+	 */
+	bool edit_interactively = false;
+	/**
+	 * List of comments to delete. Each string is a selector according to the definition of
+	 * #delete_comments.
+	 *
+	 * When #delete_all is true, this option is meaningless.
+	 *
+	 * #to_add takes precedence over #to_delete, so if the same comment appears in both lists,
+	 * the one in #to_delete applies only to the previously existing tags.
+	 *
+	 * The strings are stored in UTF-8.
+	 *
+	 * Option: --delete, --set
+	 */
+	std::list<std::string> to_delete;
+	/**
+	 * Delete all the existing comments.
+	 *
+	 * Option: --delete-all, --set-all
+	 */
+	bool delete_all = false;
+	/**
+	 * List of comments to add, in the current system encoding. For exemple `TITLE=a b c`. They
+	 * must be valid.
+	 *
+	 * The strings are stored in UTF-8.
+	 *
+	 * Options: --add, --set, --set-all
+	 */
+	std::list<std::string> to_add;
+	/**
+	 * Disable encoding conversions. OpusTags are specified to always be encoded as UTF-8, but
+	 * if for some reason a specific file contains binary tags that someone would like to
+	 * extract and set as-is, encoding conversion would get in the way.
+	 */
+	bool raw = false;
+};
+
+/**
+ * Parse the command-line arguments. Does not perform I/O related validations, but checks the
+ * consistency of its arguments. Comments are read if necessary from the given stream.
+ *
+ * On error, the state of the options structure is unspecified.
+ */
+status parse_options(int argc, char** argv, options& opt, FILE* comments);
+
+/**
+ * Print all the comments, separated by line breaks. Since a comment may contain line breaks, this
+ * output is not completely reliable, but it fits most cases.
+ *
+ * The comments must be encoded in UTF-8, and are converted to the system locale when printed.
+ *
+ * The output generated is meant to be parseable by #ot::read_comments.
+ */
+status print_comments(const std::list<std::string>& comments, FILE* output, bool raw);
+
+/**
+ * Parse the comments outputted by #ot::print_comments.
+ *
+ * The comments are converted from the system encoding to UTF-8, and returned as UTF-8.
+ */
+status read_comments(FILE* input, std::list<std::string>& comments, bool raw);
+
+/**
+ * Remove all comments matching the specified selector, which may either be a field name or a
+ * NAME=VALUE pair. The field name is case-insensitive.
+ *
+ * The strings are all UTF-8.
+ */
+void delete_comments(std::list<std::string>& comments, const std::string& selector);
+
+/**
+ * Main entry point to the opustags program, and pretty much the same as calling opustags from the
+ * command-line.
+ */
+status run(const options& opt);
+
+/** \} */
+
+}

src/system.cc

@@ -0,0 +1,190 @@
+/**
+ * \file src/system.cc
+ * \ingroup system
+ *
+ * Provide a high-level interface to system-related features, like filesystem manipulations.
+ *
+ * Ideally, all OS-specific features should be grouped here.
+ *
+ * This modules shoumd not depend on any other opustags module.
+ */
+
+#include <opustags.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+using namespace std::string_literals;
+
+ot::status ot::partial_file::open(const char* destination)
+{
+	abort();
+	final_name = destination;
+	temporary_name = final_name + ".XXXXXX.part";
+	int fd = mkstemps(const_cast<char*>(temporary_name.data()), 5);
+	if (fd == -1)
+		return {st::standard_error,
+		        "Could not create a partial file for '" + final_name + "': " +
+		        strerror(errno)};
+	file = fdopen(fd, "w");
+	if (file == nullptr)
+		return {st::standard_error,
+		        "Could not get the partial file handle to '" + temporary_name + "': " +
+		        strerror(errno)};
+	return st::ok;
+}
+
+static mode_t get_umask()
+{
+	// libc doesn’t seem to provide a way to get umask without changing it, so we need this workaround.
+	// https://www.gnu.org/software/libc/manual/html_node/Setting-Permissions.html
+	mode_t mask = umask(0);
+	umask(mask);
+	return mask;
+}
+
+/**
+ * Try reproducing the file permissions of file `source` onto file `dest`. If
+ * this fails for whatever reason, print a warning and leave the current
+ * permissions. When the source doesn’t exist, use the default file creation
+ * permissions according to umask.
+ */
+static void copy_permissions(const char* source, const char* dest)
+{
+	mode_t target_mode;
+	struct stat source_stat;
+	if (stat(source, &source_stat) == 0) {
+		// We could technically preserve a bit more than that but who
+		// would ever need S_ISUID and friends on an Opus file?
+		target_mode = source_stat.st_mode & 0777;
+	} else if (errno == ENOENT) {
+		target_mode = 0666 & ~get_umask();
+	} else {
+		fprintf(stderr, "warning: Could not read mode of %s: %s\n", source, strerror(errno));
+		return;
+	}
+	if (chmod(dest, target_mode) == -1)
+		fprintf(stderr, "warning: Could not set mode of %s: %s\n", dest, strerror(errno));
+}
+
+ot::status ot::partial_file::commit()
+{
+	if (file == nullptr)
+		return st::ok;
+	file.reset();
+	copy_permissions(final_name.c_str(), temporary_name.c_str());
+	if (rename(temporary_name.c_str(), final_name.c_str()) == -1)
+		return {st::standard_error,
+		        "Could not move the result file '" + temporary_name + "' to '" +
+		        final_name + "': " + strerror(errno) + "."};
+	return st::ok;
+}
+
+void ot::partial_file::abort()
+{
+	if (file == nullptr)
+		return;
+	file.reset();
+	remove(temporary_name.c_str());
+}
+
+ot::encoding_converter::encoding_converter(const char* from, const char* to)
+{
+	cd = iconv_open(to, from);
+	if (cd == (iconv_t) -1)
+		throw std::bad_alloc();
+}
+
+ot::encoding_converter::~encoding_converter()
+{
+	iconv_close(cd);
+}
+
+ot::status ot::encoding_converter::operator()(std::string_view in, std::string& out)
+{
+	iconv(cd, nullptr, nullptr, nullptr, nullptr);
+	out.clear();
+	out.reserve(in.size());
+	char* in_cursor = const_cast<char*>(in.data());
+	size_t in_left = in.size();
+	constexpr size_t chunk_size = 1024;
+	char chunk[chunk_size];
+	for (;;) {
+		char *out_cursor = chunk;
+		size_t out_left = chunk_size;
+		size_t rc = iconv(cd, &in_cursor, &in_left, &out_cursor, &out_left);
+
+		if (rc == (size_t) -1 && errno == E2BIG) {
+			// Loop normally.
+		} else if (rc == (size_t) -1) {
+			return {ot::st::badly_encoded, strerror(errno) + "."s};
+		} else if (rc != 0) {
+			return {ot::st::badly_encoded,
+				"Some characters could not be converted into the target encoding."};
+		}
+
+		out.append(chunk, out_cursor - chunk);
+		if (in_cursor == nullptr)
+			break;
+		else if (in_left == 0)
+			in_cursor = nullptr;
+	}
+	return ot::st::ok;
+}
+
+std::string ot::shell_escape(std::string_view word)
+{
+	std::string escaped_word;
+	// Pre-allocate the result, assuming most of the time enclosing it in single quotes is enough.
+	escaped_word.reserve(2 + word.size());
+
+	escaped_word += '\'';
+	for (char c : word) {
+		if (c == '\'')
+			escaped_word += "'\\''";
+		else if (c == '!')
+			escaped_word += "'\\!'";
+		else
+			escaped_word += c;
+	}
+	escaped_word += '\'';
+
+	return escaped_word;
+}
+
+ot::status ot::run_editor(std::string_view editor, std::string_view path)
+{
+	std::string command = std::string(editor) + " " + shell_escape(path);
+	int status = system(command.c_str());
+
+	if (status == -1)
+		return {st::standard_error, "waitpid error: "s + strerror(errno)};
+	else if (!WIFEXITED(status))
+		return {st::child_process_failed,
+		        "Child process did not terminate normally: "s + strerror(errno)};
+	else if (WEXITSTATUS(status) != 0)
+		return {st::child_process_failed,
+		        "Child process exited with " + std::to_string(WEXITSTATUS(status))};
+
+	return st::ok;
+}
+
+ot::status ot::get_file_timestamp(const char* path, timespec& mtime)
+{
+	struct stat st;
+	if (stat(path, &st) == -1)
+		return {st::standard_error, path + ": stat error: "s + strerror(errno)};
+#if defined(HAVE_STAT_ST_MTIM)
+	mtime = st.st_mtim;
+#elif defined(HAVE_STAT_ST_MTIMESPEC)
+	mtime = st.st_mtimespec;
+#else
+	mtime.tv_sec = st.st_mtime;
+	mtime.tv_nsec = st.st_mtimensec;
+#endif
+	return st::ok;
+}

src/tags.cc

@@ -1,103 +0,0 @@
-#include "tags.h"
-#include <algorithm>
-
-using namespace opustags;
-
-// ASCII only, but for tag keys it's good enough
-static bool iequals(const std::string &a, const std::string &b)
-{
-    if (a.size() != b.size())
-        return false;
-    for (size_t i = 0; i < a.size(); i++)
-        if (std::tolower(a[i]) != std::tolower(b[i]))
-            return false;
-    return true;
-}
-
-bool Tag::operator !=(const Tag &other_tag) const
-{
-    return !operator ==(other_tag);
-}
-
-bool Tag::operator ==(const Tag &other_tag) const
-{
-    return key == other_tag.key
-        && value == other_tag.value;
-}
-
-Tags::Tags()
-{
-}
-
-Tags::Tags(const std::vector<Tag> &tags) : tags(tags)
-{
-}
-
-const std::vector<Tag> Tags::get_all() const
-{
-    return tags;
-}
-
-std::string Tags::get(const std::string &key) const
-{
-    for (auto &tag : tags)
-        if (iequals(tag.key, key))
-            return tag.value;
-    throw std::runtime_error("Tag '" + key + "' not found.");
-}
-
-void Tags::add(const Tag &tag)
-{
-    tags.push_back(tag);
-}
-
-void Tags::add(const std::string &key, const std::string &value)
-{
-    tags.push_back({key, value});
-}
-
-void Tags::clear()
-{
-    tags.clear();
-}
-
-void Tags::remove(const std::string &key)
-{
-    std::vector<Tag> new_tags;
-    std::copy_if(
-        tags.begin(),
-        tags.end(),
-        std::back_inserter(new_tags),
-        [&](const Tag &tag) { return !iequals(tag.key, key); });
-    tags = new_tags;
-}
-
-bool Tags::contains(const std::string &key) const
-{
-    return std::count_if(
-        tags.begin(),
-        tags.end(),
-        [&](const Tag &tag) { return iequals(tag.key, key); }) > 0;
-}
-
-Tag opustags::parse_tag(const std::string &assoc)
-{
-    size_t eq = assoc.find_first_of('=');
-    if (eq == std::string::npos)
-        throw std::runtime_error("misconstructed tag");
-    std::string name = assoc.substr(0, eq);
-    std::string value = assoc.substr(eq + 1);
-    return { name, value };
-}
-
-bool Tags::operator !=(const Tags &other_tags) const
-{
-    return !operator ==(other_tags);
-}
-
-bool Tags::operator ==(const Tags &other_tags) const
-{
-    return vendor == other_tags.vendor
-        && extra == other_tags.extra
-        && get_all() == other_tags.get_all();
-}

src/tags.h

@@ -1,49 +0,0 @@
-#pragma once
-
-#include <map>
-#include <vector>
-#include <utility>
-
-namespace opustags {
-
-    struct Tag final
-    {
-        bool operator !=(const Tag &other_tag) const;
-        bool operator ==(const Tag &other_tag) const;
-
-        std::string key;
-        std::string value;
-    };
-
-    // A std::map adapter that keeps the order of insertion.
-    class Tags final
-    {
-    public:
-        Tags();
-        Tags(const std::vector<Tag> &tags);
-
-        const std::vector<Tag> get_all() const;
-
-        std::string get(const std::string &key) const;
-        void add(const Tag &tag);
-        void add(const std::string &key, const std::string &value);
-        void remove(const std::string &key);
-        bool contains(const std::string &key) const;
-        void clear();
-
-        bool operator !=(const Tags &other_tags) const;
-        bool operator ==(const Tags &other_tags) const;
-
-        // Additional fields are required to match the specs:
-        // https://tools.ietf.org/html/draft-ietf-codec-oggopus-14#section-5.2
-
-        std::string vendor;
-        std::string extra;
-
-    private:
-        std::vector<Tag> tags;
-    };
-
-    Tag parse_tag(const std::string &assoc); // KEY=value
-
-}

src/tags_handler.h

@@ -1,50 +0,0 @@
-#pragma once
-
-#include "tags.h"
-
-namespace opustags {
-
-    // TagsHandler define various operations related to tags and stream in
-    // order to control the main loop.
-    // In its implementation, it is expected to receive an option structure.
-    class ITagsHandler
-    {
-    public:
-        // Irrelevant streams don't even need to be parsed, so we can save some
-        // effort with this method.
-        // Returns true if the stream should be parsed, false if it should be
-        // ignored (list) or copied identically (edit).
-        virtual bool relevant(const int streamno) = 0;
-
-        // The list method is called by list_tags every time it has
-        // successfully parsed an OpusTags header.
-        virtual void list(const int streamno, const Tags &) = 0;
-
-        // Transform the tags at will.
-        // Returns true if the tags were indeed modified, false if they weren't.
-        // The latter case may be used for optimization.
-        virtual bool edit(const int streamno, Tags &) = 0;
-
-        // The work is done.
-        // When listing tags, once we've caught the streams we wanted, it's no
-        // use keeping reading the file for new streams. In that case, a true
-        // return value would abort any further processing.
-        virtual bool done() = 0;
-
-        // Signals a new stream was found.
-        // The meaning of type is in ogg::StreamType, but all you should assume
-        // is that when type is null (UNKNOWN_STREAM), list or edit won't be
-        // called.
-        virtual void start_of_stream(const int streamno, const int type) {}
-
-        // Signals the end of the file (and all the streams).
-        // If after this function is called, done() returns false, it's an
-        // error. However, it would be better to raise the error inside
-        // end_of_stream().
-        // For example, if you expect to find the stream #1 and reach the
-        // end-of-stream before finding it, better tell the user that you
-        // didn't do what he expected.
-        virtual void end_of_file() {}
-    };
-
-}

src/tags_handlers/composite_tags_handler.cc

@@ -1,44 +0,0 @@
-#include "tags_handlers/composite_tags_handler.h"
-
-using namespace opustags;
-
-void CompositeTagsHandler::add_handler(std::shared_ptr<ITagsHandler> handler)
-{
-    handlers.push_back(std::move(handler));
-}
-
-bool CompositeTagsHandler::relevant(const int streamno)
-{
-    for (const auto &handler : handlers)
-        if (handler->relevant(streamno))
-            return true;
-    return false;
-}
-
-void CompositeTagsHandler::list(const int streamno, const Tags &tags)
-{
-    for (const auto &handler : handlers)
-        handler->list(streamno, tags);
-}
-
-bool CompositeTagsHandler::edit(const int streamno, Tags &tags)
-{
-    bool modified = false;
-    for (const auto &handler : handlers)
-        modified |= handler->edit(streamno, tags);
-    return modified;
-}
-
-bool CompositeTagsHandler::done()
-{
-    for (const auto &handler : handlers)
-        if (!handler->done())
-            return false;
-    return true;
-}
-
-const std::vector<std::shared_ptr<ITagsHandler>>
-    CompositeTagsHandler::get_handlers() const
-{
-    return handlers;
-}

src/tags_handlers/composite_tags_handler.h

@@ -1,25 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <vector>
-#include "tags_handler.h"
-
-namespace opustags {
-
-    class CompositeTagsHandler final : public ITagsHandler
-    {
-    public:
-        void add_handler(std::shared_ptr<ITagsHandler> handler);
-
-        bool relevant(const int streamno) override;
-        void list(const int streamno, const Tags &) override;
-        bool edit(const int streamno, Tags &) override;
-        bool done() override;
-
-        const std::vector<std::shared_ptr<ITagsHandler>> get_handlers() const;
-
-    private:
-        std::vector<std::shared_ptr<ITagsHandler>> handlers;
-    };
-
-}

src/tags_handlers/export_tags_handler.cc

@@ -1,31 +0,0 @@
-#include "tags_handlers/export_tags_handler.h"
-
-using namespace opustags;
-
-ExportTagsHandler::ExportTagsHandler(std::ostream &output_stream)
-    : output_stream(output_stream)
-{
-}
-
-bool ExportTagsHandler::relevant(const int)
-{
-    return true;
-}
-
-void ExportTagsHandler::list(const int streamno, const Tags &tags)
-{
-    output_stream << "[Stream " << streamno << "]\n";
-    for (const auto tag : tags.get_all())
-        output_stream << tag.key << "=" << tag.value << "\n";
-    output_stream << "\n";
-}
-
-bool ExportTagsHandler::edit(const int, Tags &)
-{
-    return false;
-}
-
-bool ExportTagsHandler::done()
-{
-    return false;
-}

src/tags_handlers/export_tags_handler.h

@@ -1,22 +0,0 @@
-#pragma once
-
-#include <iostream>
-#include "tags_handler.h"
-
-namespace opustags {
-
-    class ExportTagsHandler : public ITagsHandler
-    {
-    public:
-        ExportTagsHandler(std::ostream &output_stream);
-
-        bool relevant(const int streamno) override;
-        void list(const int streamno, const Tags &) override;
-        bool edit(const int streamno, Tags &) override;
-        bool done() override;
-
-    private:
-        std::ostream &output_stream;
-    };
-
-}

src/tags_handlers/external_edit_tags_handler.cc

@@ -1,22 +0,0 @@
-#include "tags_handlers/external_edit_tags_handler.h"
-
-using namespace opustags;
-
-bool ExternalEditTagsHandler::relevant(const int streamno)
-{
-    return false;
-}
-
-void ExternalEditTagsHandler::list(const int streamno, const Tags &)
-{
-}
-
-bool ExternalEditTagsHandler::edit(const int streamno, Tags &)
-{
-    return false;
-}
-
-bool ExternalEditTagsHandler::done()
-{
-    return true;
-}

src/tags_handlers/external_edit_tags_handler.h

@@ -1,17 +0,0 @@
-#pragma once
-
-#include <iostream>
-#include "tags_handler.h"
-
-namespace opustags {
-
-    class ExternalEditTagsHandler : public ITagsHandler
-    {
-    public:
-        bool relevant(const int streamno) override;
-        void list(const int streamno, const Tags &) override;
-        bool edit(const int streamno, Tags &) override;
-        bool done() override;
-    };
-
-}

src/tags_handlers/import_tags_handler.cc

@@ -1,67 +0,0 @@
-#include <regex>
-#include "tags_handlers/import_tags_handler.h"
-
-using namespace opustags;
-
-ImportTagsHandler::ImportTagsHandler(std::istream &input_stream)
-    : parsed(false), input_stream(input_stream)
-{
-}
-
-bool ImportTagsHandler::relevant(const int)
-{
-    return true;
-}
-
-void ImportTagsHandler::list(const int, const Tags &)
-{
-}
-
-bool ImportTagsHandler::edit(const int streamno, Tags &tags)
-{
-    // the reason why we do it this way is because the tests indirectly create
-    // this handler with std::cin, and we do not want the constructor to block!
-    parse_input_stream_if_needed();
-
-    const auto old_tags = tags;
-    tags.clear();
-
-    if (tag_map.find(streamno) != tag_map.end()) {
-        const auto &source_tags = tag_map.at(streamno);
-        for (const auto &source_tag : source_tags.get_all())
-            tags.add(source_tag.key, source_tag.value);
-    }
-
-    return old_tags != tags;
-}
-
-bool ImportTagsHandler::done()
-{
-    return false;
-}
-
-void ImportTagsHandler::parse_input_stream_if_needed()
-{
-    if (parsed)
-        return;
-    parsed = true;
-
-    const std::regex whitespace_regex("^\\s*$");
-    const std::regex stream_header_regex(
-        "^\\s*\\[stream\\s+(\\d+)\\]\\s*$", std::regex_constants::icase);
-    const std::regex tag_regex(
-        "^\\s*([a-z0-9]+)\\s*=\\s*(.*?)\\s*$", std::regex_constants::icase);
-
-    int current_stream_number = 1;
-    std::string line;
-    while (std::getline(input_stream, line)) {
-        std::smatch match;
-        if (std::regex_match(line, match, stream_header_regex)) {
-            current_stream_number = std::atoi(match[1].str().c_str());
-        } else if (std::regex_match(line, match, tag_regex)) {
-            tag_map[current_stream_number].add(match[1], match[2]);
-        } else if (!std::regex_match(line, match, whitespace_regex)) {
-            throw std::runtime_error("Malformed input data near line " + line);
-        }
-    }
-}

src/tags_handlers/import_tags_handler.h

@@ -1,27 +0,0 @@
-#pragma once
-
-#include <iostream>
-#include <map>
-#include "tags_handler.h"
-
-namespace opustags {
-
-    class ImportTagsHandler : public ITagsHandler
-    {
-    public:
-        ImportTagsHandler(std::istream &input_stream);
-
-        bool relevant(const int streamno) override;
-        void list(const int streamno, const Tags &) override;
-        bool edit(const int streamno, Tags &) override;
-        bool done() override;
-
-    private:
-        void parse_input_stream_if_needed();
-
-        bool parsed;
-        std::istream &input_stream;
-        std::map<int, Tags> tag_map;
-    };
-
-}

src/tags_handlers/insertion_tags_handler.cc

@@ -1,28 +0,0 @@
-#include "tags_handlers/insertion_tags_handler.h"
-#include "tags_handlers_errors.h"
-
-using namespace opustags;
-
-InsertionTagsHandler::InsertionTagsHandler(
-    const int streamno,
-    const std::string &tag_key,
-    const std::string &tag_value)
-    : StreamTagsHandler(streamno), tag_key(tag_key), tag_value(tag_value)
-{
-}
-
-std::string InsertionTagsHandler::get_tag_key() const
-{
-    return tag_key;
-}
-
-std::string InsertionTagsHandler::get_tag_value() const
-{
-    return tag_value;
-}
-
-bool InsertionTagsHandler::edit_impl(Tags &tags)
-{
-    tags.add(tag_key, tag_value);
-    return true;
-}

src/tags_handlers/insertion_tags_handler.h

@@ -1,26 +0,0 @@
-#pragma once
-
-#include "tags_handlers/stream_tags_handler.h"
-
-namespace opustags {
-
-    class InsertionTagsHandler : public StreamTagsHandler
-    {
-    public:
-        InsertionTagsHandler(
-            const int streamno,
-            const std::string &tag_key,
-            const std::string &tag_value);
-
-        std::string get_tag_key() const;
-        std::string get_tag_value() const;
-
-    protected:
-        bool edit_impl(Tags &) override;
-
-    private:
-        const std::string tag_key;
-        const std::string tag_value;
-    };
-
-}

src/tags_handlers/listing_tags_handler.cc

@@ -1,16 +0,0 @@
-#include "tags_handlers/listing_tags_handler.h"
-
-using namespace opustags;
-
-ListingTagsHandler::ListingTagsHandler(
-    const int streamno,
-    std::ostream &output_stream)
-    : StreamTagsHandler(streamno), output_stream(output_stream)
-{
-}
-
-void ListingTagsHandler::list_impl(const Tags &tags)
-{
-    for (const auto &tag : tags.get_all())
-        output_stream << tag.key << "=" << tag.value << "\n";
-}

src/tags_handlers/listing_tags_handler.h

@@ -1,20 +0,0 @@
-#pragma once
-
-#include <iostream>
-#include "tags_handlers/stream_tags_handler.h"
-
-namespace opustags {
-
-    class ListingTagsHandler : public StreamTagsHandler
-    {
-    public:
-        ListingTagsHandler(const int streamno, std::ostream &output_stream);
-
-    protected:
-        void list_impl(const Tags &) override;
-
-    private:
-        std::ostream &output_stream;
-    };
-
-}

src/tags_handlers/modification_tags_handler.cc

@@ -1,33 +0,0 @@
-#include "tags_handlers/modification_tags_handler.h"
-
-using namespace opustags;
-
-ModificationTagsHandler::ModificationTagsHandler(
-    const int streamno,
-    const std::string &tag_key,
-    const std::string &tag_value)
-    : StreamTagsHandler(streamno), tag_key(tag_key), tag_value(tag_value)
-{
-}
-
-std::string ModificationTagsHandler::get_tag_key() const
-{
-    return tag_key;
-}
-
-std::string ModificationTagsHandler::get_tag_value() const
-{
-    return tag_value;
-}
-
-bool ModificationTagsHandler::edit_impl(Tags &tags)
-{
-    if (tags.contains(tag_key)) {
-        if (tags.get(tag_key) == tag_value)
-            return false;
-        tags.remove(tag_key);
-    }
-
-    tags.add(tag_key, tag_value);
-    return true;
-}

src/tags_handlers/modification_tags_handler.h

@@ -1,26 +0,0 @@
-#pragma once
-
-#include "tags_handlers/stream_tags_handler.h"
-
-namespace opustags {
-
-    class ModificationTagsHandler : public StreamTagsHandler
-    {
-    public:
-        ModificationTagsHandler(
-            const int streamno,
-            const std::string &tag_key,
-            const std::string &tag_value);
-
-        std::string get_tag_key() const;
-        std::string get_tag_value() const;
-
-    protected:
-        bool edit_impl(Tags &) override;
-
-    private:
-        const std::string tag_key;
-        const std::string tag_value;
-    };
-
-}

src/tags_handlers/removal_tags_handler.cc

@@ -1,35 +0,0 @@
-#include "tags_handlers/removal_tags_handler.h"
-#include "tags_handlers_errors.h"
-
-using namespace opustags;
-
-RemovalTagsHandler::RemovalTagsHandler(const int streamno)
-    : StreamTagsHandler(streamno)
-{
-}
-
-RemovalTagsHandler::RemovalTagsHandler(
-    const int streamno, const std::string &tag_key)
-    : StreamTagsHandler(streamno), tag_key(tag_key)
-{
-}
-
-std::string RemovalTagsHandler::get_tag_key() const
-{
-    return tag_key;
-}
-
-bool RemovalTagsHandler::edit_impl(Tags &tags)
-{
-    if (tag_key.empty()) {
-        const auto anything_removed = tags.get_all().size() > 0;
-        tags.clear();
-        return anything_removed;
-    } else {
-        if (!tags.contains(tag_key))
-            return false;
-
-        tags.remove(tag_key);
-        return true;
-    }
-}

src/tags_handlers/removal_tags_handler.h

@@ -1,22 +0,0 @@
-#pragma once
-
-#include "tags_handlers/stream_tags_handler.h"
-
-namespace opustags {
-
-    class RemovalTagsHandler : public StreamTagsHandler
-    {
-    public:
-        RemovalTagsHandler(const int streamno);
-        RemovalTagsHandler(const int streamno, const std::string &tag_key);
-
-        std::string get_tag_key() const;
-
-    protected:
-        bool edit_impl(Tags &) override;
-
-    private:
-        const std::string tag_key;
-    };
-
-}

src/tags_handlers/stream_tags_handler.cc

@@ -1,59 +0,0 @@
-#include "tags_handlers/stream_tags_handler.h"
-
-#include <iostream>
-
-using namespace opustags;
-
-const int StreamTagsHandler::ALL_STREAMS = -1;
-
-StreamTagsHandler::StreamTagsHandler(const int streamno)
-    : streamno(streamno), work_finished(false)
-{
-}
-
-int StreamTagsHandler::get_streamno() const
-{
-    return streamno;
-}
-
-bool StreamTagsHandler::relevant(const int streamno)
-{
-    return streamno == this->streamno || this->streamno == ALL_STREAMS;
-}
-
-void StreamTagsHandler::list(const int streamno, const Tags &tags)
-{
-    if (!relevant(streamno))
-        return;
-    list_impl(tags);
-    work_finished = this->streamno != ALL_STREAMS;
-}
-
-bool StreamTagsHandler::edit(const int streamno, Tags &tags)
-{
-    if (!relevant(streamno))
-        return false;
-    const auto ret = edit_impl(tags);
-    work_finished = this->streamno != ALL_STREAMS;
-    return ret;
-}
-
-bool StreamTagsHandler::done()
-{
-    return work_finished;
-}
-
-void StreamTagsHandler::end_of_file()
-{
-    if (!work_finished && streamno != ALL_STREAMS)
-        std::cerr << "warning: stream " << streamno << " wasn't found" << std::endl;
-}
-
-void StreamTagsHandler::list_impl(const Tags &)
-{
-}
-
-bool StreamTagsHandler::edit_impl(Tags &)
-{
-    return false;
-}

src/tags_handlers/stream_tags_handler.h

@@ -1,33 +0,0 @@
-#pragma once
-
-#include "tags_handler.h"
-
-namespace opustags {
-
-    // Base handler that holds the stream number it's supposed to work with
-    // and performs the usual boilerplate.
-    class StreamTagsHandler : public ITagsHandler
-    {
-    public:
-        static const int ALL_STREAMS;
-
-        StreamTagsHandler(const int streamno);
-
-        int get_streamno() const;
-
-        bool relevant(const int streamno) override;
-        void list(const int streamno, const Tags &) override;
-        bool edit(const int streamno, Tags &) override;
-        bool done() override;
-        void end_of_file() override;
-
-    protected:
-        virtual void list_impl(const Tags &);
-        virtual bool edit_impl(Tags &);
-
-    private:
-        const int streamno;
-        bool work_finished;
-    };
-
-}

src/tags_handlers_errors.cc

@@ -1,13 +0,0 @@
-#include "tags_handlers_errors.h"
-
-using namespace opustags;
-
-TagAlreadyExistsError::TagAlreadyExistsError(const std::string &tag_key)
-    : std::runtime_error("Tag already exists: " + tag_key)
-{
-}
-
-TagDoesNotExistError::TagDoesNotExistError(const std::string &tag_key)
-    : std::runtime_error("Tag does not exist: " + tag_key)
-{
-}

src/tags_handlers_errors.h

@@ -1,17 +0,0 @@
-#pragma once
-
-#include <stdexcept>
-
-namespace opustags {
-
-    struct TagAlreadyExistsError : std::runtime_error
-    {
-        TagAlreadyExistsError(const std::string &tag_key);
-    };
-
-    struct TagDoesNotExistError : std::runtime_error
-    {
-        TagDoesNotExistError(const std::string &tag_key);
-    };
-
-}

src/version.h.in

@@ -1,10 +0,0 @@
-#pragma once
-
-#include <string>
-
-namespace opustags {
-
-    static const std::string version_short = "@VERSION_SHORT@";
-    static const std::string version_long = "@VERSION_LONG@";
-
-}

t/CMakeLists.txt

@@ -0,0 +1,22 @@
+add_executable(system.t EXCLUDE_FROM_ALL system.cc)
+target_link_libraries(system.t ot)
+
+add_executable(opus.t EXCLUDE_FROM_ALL opus.cc)
+target_link_libraries(opus.t ot)
+
+add_executable(ogg.t EXCLUDE_FROM_ALL ogg.cc)
+target_link_libraries(ogg.t ot)
+
+add_executable(cli.t EXCLUDE_FROM_ALL cli.cc)
+target_link_libraries(cli.t ot)
+
+add_executable(oggdump EXCLUDE_FROM_ALL oggdump.cc)
+target_link_libraries(oggdump ot)
+
+configure_file(gobble.opus . COPYONLY)
+
+add_custom_target(
+	check
+	COMMAND prove "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}"
+	DEPENDS opustags gobble.opus system.t opus.t ogg.t cli.t
+)

t/cli.cc

@@ -0,0 +1,197 @@
+#include <opustags.h>
+#include "tap.h"
+
+#include <string.h>
+
+using namespace std::literals::string_literals;
+
+void check_read_comments()
+{
+	std::list<std::string> comments;
+	ot::status rc;
+	{
+		std::string txt = "TITLE=a b c\n\nARTIST=X\nArtist=Y\n"s;
+		ot::file input = fmemopen((char*) txt.data(), txt.size(), "r");
+		rc = ot::read_comments(input.get(), comments, false);
+		if (rc != ot::st::ok)
+			throw failure("could not read comments");
+		auto&& expected = {"TITLE=a b c", "ARTIST=X", "Artist=Y"};
+		if (!std::equal(comments.begin(), comments.end(), expected.begin(), expected.end()))
+			throw failure("parsed user comments did not match expectations");
+	}
+	{
+		std::string txt = "CORRUPTED=\xFF\xFF\n"s;
+		ot::file input = fmemopen((char*) txt.data(), txt.size(), "r");
+		rc = ot::read_comments(input.get(), comments, false);
+		if (rc != ot::st::badly_encoded)
+			throw failure("did not get the expected error reading corrupted data");
+	}
+	{
+		std::string txt = "RAW=\xFF\xFF\n"s;
+		ot::file input = fmemopen((char*) txt.data(), txt.size(), "r");
+		rc = ot::read_comments(input.get(), comments, true);
+		if (rc != ot::st::ok)
+			throw failure("could not read comments");
+		if (comments.front() != "RAW=\xFF\xFF")
+			throw failure("parsed user comments did not match expectations");
+	}
+	{
+		std::string txt = "MALFORMED\n"s;
+		ot::file input = fmemopen((char*) txt.data(), txt.size(), "r");
+		rc = ot::read_comments(input.get(), comments, false);
+		if (rc != ot::st::error)
+			throw failure("did not get the expected error reading malformed comments");
+	}
+}
+
+/**
+ * Wrap #ot::parse_options with a higher-level interface much more convenient for testing.
+ * In practice, the argc/argv combo are enough though for the current state of opustags.
+ */
+static ot::status parse_options(const std::vector<const char*>& args, ot::options& opt, FILE *comments)
+{
+	int argc = args.size();
+	char* argv[argc];
+	for (int i = 0; i < argc; ++i)
+		argv[i] = strdup(args[i]);
+	ot::status rc = ot::parse_options(argc, argv, opt, comments);
+	for (int i = 0; i < argc; ++i)
+		free(argv[i]);
+	return rc;
+}
+
+void check_good_arguments()
+{
+	auto parse = [](std::vector<const char*> args) {
+		ot::options opt;
+		std::string txt = "N=1\n"s;
+		ot::file input = fmemopen((char*) txt.data(), txt.size(), "r");
+		ot::status rc = parse_options(args, opt, input.get());
+		if (rc.code != ot::st::ok)
+			throw failure("unexpected option parsing error");
+		return opt;
+	};
+
+	ot::options opt;
+	opt = parse({"opustags", "--help", "x", "-o", "y"});
+	if (!opt.print_help)
+		throw failure("did not catch --help");
+
+	opt = parse({"opustags", "x", "--output", "y", "-D", "-s", "X=Y Z", "-d", "a=b"});
+	if (opt.paths_in.size() != 1 || opt.paths_in.front() != "x" || !opt.path_out ||
+	    opt.path_out != "y" || !opt.delete_all || opt.overwrite || opt.to_delete.size() != 2 ||
+	    opt.to_delete.front() != "X" || *std::next(opt.to_delete.begin()) != "a=b" ||
+	    opt.to_add != std::list<std::string>{"X=Y Z"})
+		throw failure("unexpected option parsing result for case #1");
+
+	opt = parse({"opustags", "-S", "x", "-S", "-a", "x=y z", "-i"});
+	if (opt.paths_in.size() != 1 || opt.paths_in.front() != "x" || opt.path_out ||
+	    !opt.overwrite || opt.to_delete.size() != 0 ||
+	    opt.to_add != std::list<std::string>{"N=1", "x=y z"})
+		throw failure("unexpected option parsing result for case #2");
+
+	opt = parse({"opustags", "-i", "x", "y", "z"});
+	if (opt.paths_in.size() != 3 || opt.paths_in[0] != "x" || opt.paths_in[1] != "y" ||
+	    opt.paths_in[2] != "z" || !opt.overwrite || !opt.in_place)
+		throw failure("unexpected option parsing result for case #3");
+
+	opt = parse({"opustags", "-ie", "x"});
+	if (opt.paths_in.size() != 1 || opt.paths_in[0] != "x" ||
+	    !opt.edit_interactively || !opt.overwrite || !opt.in_place)
+		throw failure("unexpected option parsing result for case #4");
+
+	opt = parse({"opustags", "-a", "X=\xFF", "--raw", "x"});
+	if (!opt.raw || opt.to_add.front() != "X=\xFF")
+		throw failure("--raw did not disable transcoding");
+}
+
+void check_bad_arguments()
+{
+	auto error_code_case = [](std::vector<const char*> args, const char* message, ot::st error_code, const std::string& name) {
+		ot::options opt;
+		std::string txt = "N=1\nINVALID"s;
+		ot::file input = fmemopen((char*) txt.data(), txt.size(), "r");
+		ot::status rc = parse_options(args, opt, input.get());
+		if (rc.code != error_code)
+			throw failure("bad error code for case " + name);
+		if (rc.message != message)
+			throw failure("bad error message for case " + name + ", got: " + rc.message);
+	};
+	auto error_case = [&error_code_case](std::vector<const char*> args, const char* message, const std::string& name) {
+		 error_code_case(args, message, ot::st::bad_arguments, name);
+	};
+	error_case({"opustags"}, "No arguments specified. Use -h for help.", "no arguments");
+	error_case({"opustags", "-a", "X"}, "Comment does not contain an equal sign: X.", "bad comment for -a");
+	error_case({"opustags", "--set", "X"}, "Comment does not contain an equal sign: X.", "bad comment for --set");
+	error_case({"opustags", "-a"}, "Missing value for option '-a'.", "short option with missing value");
+	error_case({"opustags", "--add"}, "Missing value for option '--add'.", "long option with missing value");
+	error_case({"opustags", "-x"}, "Unrecognized option '-x'.", "unrecognized short option");
+	error_case({"opustags", "--derp"}, "Unrecognized option '--derp'.", "unrecognized long option");
+	error_case({"opustags", "-x=y"}, "Unrecognized option '-x'.", "unrecognized short option with value");
+	error_case({"opustags", "--derp=y"}, "Unrecognized option '--derp=y'.", "unrecognized long option with value");
+	error_case({"opustags", "-aX=Y"}, "Exactly one input file must be specified.", "no input file");
+	error_case({"opustags", "-i", "-o", "/dev/null", "-"}, "Cannot combine --in-place and --output.", "in-place + output");
+	error_case({"opustags", "-S", "-"}, "Cannot use standard input as input file when --set-all is specified.",
+	                                    "set all and read opus from stdin");
+	error_case({"opustags", "-i", "-"}, "Cannot modify standard input in place.", "write stdin in-place");
+	error_case({"opustags", "-o", "x", "--output", "y", "z"},
+	           "Cannot specify --output more than once.", "double output");
+	error_code_case({"opustags", "-S", "x"}, "Malformed tag: INVALID", ot::st::error, "attempt to read invalid argument with -S");
+	error_case({"opustags", "-o", "", "--output", "y", "z"},
+	           "Cannot specify --output more than once.", "double output with first filename empty");
+	error_case({"opustags", "-e", "-i", "x", "y"},
+	           "Exactly one input file must be specified.", "editing interactively two files at once");
+	error_case({"opustags", "--edit", "-", "-o", "x"},
+	           "Cannot edit interactively when standard input or standard output are already used.",
+	           "editing interactively from stdandard intput");
+	error_case({"opustags", "--edit", "x", "-o", "-"},
+	           "Cannot edit interactively when standard input or standard output are already used.",
+	           "editing interactively to stdandard output");
+	error_case({"opustags", "--edit", "x"}, "Cannot edit interactively when no output is specified.", "editing without output");
+	error_case({"opustags", "--edit", "x", "-i", "-a", "X=Y"}, "Cannot mix --edit with -adDsS.", "mixing -e and -a");
+	error_case({"opustags", "--edit", "x", "-i", "-d", "X"}, "Cannot mix --edit with -adDsS.", "mixing -e and -d");
+	error_case({"opustags", "--edit", "x", "-i", "-D"}, "Cannot mix --edit with -adDsS.", "mixing -e and -D");
+	error_case({"opustags", "--edit", "x", "-i", "-S"}, "Cannot mix --edit with -adDsS.", "mixing -e and -S");
+	error_case({"opustags", "-d", "\xFF", "x"},
+	           "Could not encode argument into UTF-8: Invalid or incomplete multibyte or wide character.",
+	           "-d with binary data");
+	error_case({"opustags", "-a", "X=\xFF", "x"},
+	           "Could not encode argument into UTF-8: Invalid or incomplete multibyte or wide character.",
+	           "-a with binary data");
+	error_case({"opustags", "-s", "X=\xFF", "x"},
+	           "Could not encode argument into UTF-8: Invalid or incomplete multibyte or wide character.",
+	           "-s with binary data");
+}
+
+static void check_delete_comments()
+{
+	using C = std::list<std::string>;
+	C original = {"TITLE=X", "Title=Y", "Title=Z", "ARTIST=A", "artIst=B"};
+
+	C edited = original;
+	ot::delete_comments(edited, "derp");
+	if (!std::equal(edited.begin(), edited.end(), original.begin(), original.end()))
+		throw failure("should not have deleted anything");
+
+	ot::delete_comments(edited, "Title");
+	C expected = {"ARTIST=A", "artIst=B"};
+	if (!std::equal(edited.begin(), edited.end(), expected.begin(), expected.end()))
+		throw failure("did not delete all titles correctly");
+
+	edited = original;
+	ot::delete_comments(edited, "titlE=Y");
+	ot::delete_comments(edited, "Title=z");
+	expected = {"TITLE=X", "Title=Z", "ARTIST=A", "artIst=B"};
+	if (!std::equal(edited.begin(), edited.end(), expected.begin(), expected.end()))
+		throw failure("did not delete a specific title correctly");
+}
+
+int main(int argc, char **argv)
+{
+	std::cout << "1..4\n";
+	run(check_read_comments, "check tags parsing");
+	run(check_good_arguments, "check options parsing");
+	run(check_bad_arguments, "check options parsing errors");
+	run(check_delete_comments, "delete comments");
+	return 0;
+}

t/ogg.cc

@@ -0,0 +1,170 @@
+#include <opustags.h>
+#include "tap.h"
+
+#include <string.h>
+
+static void check_ref_ogg()
+{
+	ot::file input = fopen("gobble.opus", "r");
+	if (input == nullptr)
+		throw failure("could not open gobble.opus");
+
+	ot::ogg_reader reader(input.get());
+
+	ot::status rc = reader.next_page();
+	if (rc != ot::st::ok)
+		throw failure("could not read the first page");
+	if (!ot::is_opus_stream(reader.page))
+		throw failure("failed to identify the stream as opus");
+	rc = reader.process_header_packet([](ogg_packet& p) {
+		if (p.bytes != 19)
+			throw failure("unexpected length for the first packet");
+		return ot::st::ok;
+	});
+	if (rc != ot::st::ok)
+		throw failure("could not read the first packet");
+
+	rc = reader.next_page();
+	if (rc != ot::st::ok)
+		throw failure("could not read the second page");
+	rc = reader.process_header_packet([](ogg_packet& p) {
+		if (p.bytes != 62)
+			throw failure("unexpected length for the second packet");
+		return ot::st::ok;
+	});
+	if (rc != ot::st::ok)
+		throw failure("could not read the second packet");
+
+	while (!ogg_page_eos(&reader.page)) {
+		rc = reader.next_page();
+		if (rc != ot::st::ok)
+			throw failure("failure reading a page");
+	}
+	rc = reader.next_page();
+	if (rc != ot::st::end_of_stream)
+		throw failure("did not correctly detect the end of stream");
+}
+
+static ogg_packet make_packet(const char* contents)
+{
+	ogg_packet op {};
+	op.bytes = strlen(contents);
+	op.packet = (unsigned char*) contents;
+	return op;
+}
+
+static bool same_packet(const ogg_packet& lhs, const ogg_packet& rhs)
+{
+	return lhs.bytes == rhs.bytes && memcmp(lhs.packet, rhs.packet, lhs.bytes) == 0;
+}
+
+/**
+ * Build an in-memory Ogg stream using ogg_writer, and then read it with ogg_reader.
+ */
+static void check_memory_ogg()
+{
+	ogg_packet first_packet  = make_packet("First");
+	ogg_packet second_packet = make_packet("Second");
+	std::vector<unsigned char> my_ogg(128);
+	size_t my_ogg_size;
+	ot::status rc;
+
+	{
+		ot::file output = fmemopen(my_ogg.data(), my_ogg.size(), "w");
+		if (output == nullptr)
+			throw failure("could not open the output stream");
+		ot::ogg_writer writer(output.get());
+		writer.write_header_packet(1234, 0, first_packet);
+		if (rc != ot::st::ok)
+			throw failure("could not write the first packet");
+		writer.write_header_packet(1234, 1, second_packet);
+		if (rc != ot::st::ok)
+			throw failure("could not write the second packet");
+		my_ogg_size = ftell(output.get());
+		if (my_ogg_size != 67)
+			throw failure("unexpected output size");
+	}
+
+	{
+		ot::file input = fmemopen(my_ogg.data(), my_ogg_size, "r");
+		if (input == nullptr)
+			throw failure("could not open the input stream");
+		ot::ogg_reader reader(input.get());
+		rc = reader.next_page();
+		if (rc != ot::st::ok)
+			throw failure("could not read the first page");
+		rc = reader.process_header_packet([&first_packet](ogg_packet &p) {
+			if (!same_packet(p, first_packet))
+				throw failure("unexpected content in the first packet");
+			return ot::st::ok;
+		});
+		if (rc != ot::st::ok)
+			throw failure("could not read the first packet");
+		rc = reader.next_page();
+		if (rc != ot::st::ok)
+			throw failure("could not read the second page");
+		rc = reader.process_header_packet([&second_packet](ogg_packet &p) {
+			if (!same_packet(p, second_packet))
+				throw failure("unexpected content in the second packet");
+			return ot::st::ok;
+		});
+		if (rc != ot::st::ok)
+			throw failure("could not read the second packet");
+		rc = reader.next_page();
+		if (rc != ot::st::end_of_stream)
+			throw failure("unexpected third page");
+	}
+}
+
+void check_bad_stream()
+{
+	auto err_msg = "did not detect the stream is not an ogg stream";
+	ot::file input = fmemopen((void*) err_msg, 20, "r");
+	ot::ogg_reader reader(input.get());
+	ot::status rc = reader.next_page();
+	if (rc != ot::st::bad_stream)
+		throw failure(err_msg);
+}
+
+void check_identification()
+{
+	auto good_header = (unsigned char*)
+		"\x4f\x67\x67\x53\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x42\xf2"
+		"\xe6\xc7\x00\x00\x00\x00\x7e\xc3\x57\x2b\x01\x13";
+	auto good_body = (unsigned char*) "OpusHeadABCD";
+
+	ogg_page id;
+	id.header = good_header;
+	id.header_len = 28;
+	id.body = good_body;
+	id.body_len = 12;
+	if (!ot::is_opus_stream(id))
+		throw failure("could not identify opus header");
+
+	// Bad body
+	id.body_len = 7;
+	if (ot::is_opus_stream(id))
+		throw failure("opus header was too short to be valid");
+	id.body_len = 12;
+	id.body = (unsigned char*) "Not_OpusHead";
+	if (ot::is_opus_stream(id))
+		throw failure("was not an opus header");
+	id.body = good_body;
+
+	// Remove the BoS bit from the header.
+	id.header = (unsigned char*)
+		"\x4f\x67\x67\x53\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x42\xf2"
+		"\xe6\xc7\x00\x00\x00\x00\x7e\xc3\x57\x2b\x01\x13";
+	if (ot::is_opus_stream(id))
+		throw failure("was not the beginning of a stream");
+}
+
+int main(int argc, char **argv)
+{
+	std::cout << "1..4\n";
+	run(check_ref_ogg, "check a reference ogg stream");
+	run(check_memory_ogg, "build and check a fresh stream");
+	run(check_bad_stream, "read a non-ogg stream");
+	run(check_identification, "stream identification");
+	return 0;
+}

t/oggdump.cc

@@ -0,0 +1,42 @@
+/**
+ * \file t/oggdump.cc
+ *
+ * Dump brief information about the pages containted in an Ogg file.
+ *
+ * This tool is not build by default or installed, and is mainly meant to help understand how Ogg
+ * files are built, and to debug.
+ */
+
+#include <opustags.h>
+
+#include <iostream>
+#include <string.h>
+
+int main(int argc, char** argv)
+{
+	if (argc != 2) {
+		std::cerr << "Usage: oggdump FILE\n";
+		return 1;
+	}
+	ot::file input = fopen(argv[1], "r");
+	if (input == nullptr) {
+		std::cerr << "Error opening '" << argv[1] << "': " << strerror(errno) << "\n";
+		return 1;
+	}
+	ot::ogg_reader reader(input.get());
+	ot::status rc;
+	while ((rc = reader.read_page()) == ot::st::ok) {
+		std::cout << "Stream " << ogg_page_serialno(&reader.page) << ", "
+		             "page #" << ogg_page_pageno(&reader.page) << ", "
+		          << ogg_page_packets(&reader.page) << " packet(s)";
+		if (ogg_page_bos(&reader.page)) std::cout << ", BoS";
+		if (ogg_page_eos(&reader.page)) std::cout << ", EoS";
+		if (ogg_page_continued(&reader.page)) std::cout << ", continued";
+		std::cout << "\n";
+	}
+	if (rc != ot::st::ok && rc != ot::st::end_of_stream) {
+		std::cerr << "error: " << rc.message << "\n";
+		return 1;
+	}
+	return 0;
+}

t/opus.cc

@@ -0,0 +1,147 @@
+#include <opustags.h>
+#include "tap.h"
+
+#include <string.h>
+
+using namespace std::literals::string_literals;
+
+static const char standard_OpusTags[] =
+	"OpusTags"
+	"\x14\x00\x00\x00" "opustags test packet"
+	"\x02\x00\x00\x00"
+	"\x09\x00\x00\x00" "TITLE=Foo"
+	"\x0a\x00\x00\x00" "ARTIST=Bar";
+
+static void parse_standard()
+{
+	ot::opus_tags tags;
+	ogg_packet op;
+	op.bytes = sizeof(standard_OpusTags) - 1;
+	op.packet = (unsigned char*) standard_OpusTags;
+	auto rc = ot::parse_tags(op, tags);
+	if (rc != ot::st::ok)
+		throw failure("ot::parse_tags did not return ok");
+	if (tags.vendor != "opustags test packet")
+		throw failure("bad vendor string");
+	if (tags.comments.size() != 2)
+		throw failure("bad number of comments");
+	auto it = tags.comments.begin();
+	if (*it != "TITLE=Foo")
+		throw failure("bad title");
+	++it;
+	if (*it != "ARTIST=Bar")
+		throw failure("bad artist");
+	if (tags.extra_data.size() != 0)
+		throw failure("found mysterious padding data");
+}
+
+/**
+ * Try parse_tags with packets that should not valid, or that might even
+ * corrupt the memory. Run this one with valgrind to ensure we're not
+ * overflowing.
+ */
+static void parse_corrupted()
+{
+	size_t size = sizeof(standard_OpusTags);
+	char packet[size];
+	memcpy(packet, standard_OpusTags, size);
+	ot::opus_tags tags;
+	ogg_packet op;
+	op.packet = (unsigned char*) packet;
+	op.bytes = size;
+
+	char* header_data = packet;
+	char* vendor_length = header_data + 8;
+	char* vendor_string = vendor_length + 4;
+	char* comment_count = vendor_string + *vendor_length;
+	char* first_comment_length = comment_count + 4;
+	char* first_comment_data = first_comment_length + 4;
+	char* end = packet + size;
+
+	op.bytes = 7;
+	if (ot::parse_tags(op, tags) != ot::st::cut_magic_number)
+		throw failure("did not detect the overflowing magic number");
+	op.bytes = 11;
+	if (ot::parse_tags(op, tags) != ot::st::cut_vendor_length)
+		throw failure("did not detect the overflowing vendor string length");
+	op.bytes = size;
+
+	header_data[0] = 'o';
+	if (ot::parse_tags(op, tags) != ot::st::bad_magic_number)
+		throw failure("did not detect the bad magic number");
+	header_data[0] = 'O';
+
+	*vendor_length = end - vendor_string + 1;
+	if (ot::parse_tags(op, tags) != ot::st::cut_vendor_data)
+		throw failure("did not detect the overflowing vendor string");
+	*vendor_length = end - vendor_string - 3;
+	if (ot::parse_tags(op, tags) != ot::st::cut_comment_count)
+		throw failure("did not detect the overflowing comment count");
+	*vendor_length = comment_count - vendor_string;
+
+	++*comment_count;
+	if (ot::parse_tags(op, tags) != ot::st::cut_comment_length)
+		throw failure("did not detect the overflowing comment length");
+	*first_comment_length = end - first_comment_data + 1;
+	if (ot::parse_tags(op, tags) != ot::st::cut_comment_data)
+		throw failure("did not detect the overflowing comment data");
+}
+
+static void recode_standard()
+{
+	ot::opus_tags tags;
+	ogg_packet op;
+	op.bytes = sizeof(standard_OpusTags) - 1;
+	op.packet = (unsigned char*) standard_OpusTags;
+	auto rc = ot::parse_tags(op, tags);
+	if (rc != ot::st::ok)
+		throw failure("ot::parse_tags did not return ok");
+	auto packet = ot::render_tags(tags);
+	if (packet.b_o_s != 0)
+		throw failure("b_o_s should not be set");
+	if (packet.e_o_s != 0)
+		throw failure("e_o_s should not be set");
+	if (packet.granulepos != 0)
+		throw failure("granule_post should be 0");
+	if (packet.packetno != 1)
+		throw failure("packetno should be 1");
+	if (packet.bytes != sizeof(standard_OpusTags) - 1)
+		throw failure("the packet is not the right size");
+	if (memcmp(packet.packet, standard_OpusTags, packet.bytes) != 0)
+		throw failure("the rendered packet is not what we expected");
+}
+
+static void recode_padding()
+{
+	ot::opus_tags tags;
+	std::string padded_OpusTags(standard_OpusTags, sizeof(standard_OpusTags));
+	// ^ note: padded_OpusTags ends with a null byte here
+	padded_OpusTags += "hello";
+	ogg_packet op;
+	op.bytes = padded_OpusTags.size();
+	op.packet = (unsigned char*) padded_OpusTags.data();
+
+	auto rc = ot::parse_tags(op, tags);
+	if (rc != ot::st::ok)
+		throw failure("ot::parse_tags did not return ok");
+	if (tags.extra_data != "\0hello"s)
+		throw failure("corrupted extra data");
+	// recode the packet and ensure it's exactly the same
+	auto packet = ot::render_tags(tags);
+	if (static_cast<size_t>(packet.bytes) < padded_OpusTags.size())
+		throw failure("the packet was truncated");
+	if (static_cast<size_t>(packet.bytes) > padded_OpusTags.size())
+		throw failure("the packet got too big");
+	if (memcmp(packet.packet, padded_OpusTags.data(), packet.bytes) != 0)
+		throw failure("the rendered packet is not what we expected");
+}
+
+int main()
+{
+	std::cout << "1..4\n";
+	run(parse_standard, "parse a standard OpusTags packet");
+	run(parse_corrupted, "correctly reject invalid packets");
+	run(recode_standard, "recode a standard OpusTags packet");
+	run(recode_padding, "recode a OpusTags packet with padding");
+	return 0;
+}

t/opustags.t

@@ -0,0 +1,313 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use utf8;
+
+use Test::More tests => 50;
+
+use Digest::MD5;
+use File::Basename;
+use File::Copy;
+use IPC::Open3;
+use List::MoreUtils qw(any);
+use Symbol 'gensym';
+
+my $opustags = '../opustags';
+BAIL_OUT("$opustags does not exist or is not executable") if (! -x $opustags);
+
+my $is_utf8;
+open(my $ctype, 'locale -k LC_CTYPE |');
+while (<$ctype>) { $is_utf8 = 1 if (/^charmap="UTF-?8"$/i) }
+close($ctype);
+BAIL_OUT("this test must be run from an UTF-8 environment") unless $is_utf8;
+
+sub opustags {
+	my %opt;
+	%opt = %{pop @_} if ref $_[-1];
+	my ($pid, $pin, $pout, $perr);
+	$perr = gensym;
+	$pid = open3($pin, $pout, $perr, $opustags, @_);
+	binmode($pin, $opt{mode} // ':utf8');
+	binmode($pout, $opt{mode} // ':utf8');
+	binmode($perr, ':utf8');
+	local $/;
+	print $pin $opt{in} if defined $opt{in};
+	close $pin;
+	my $out = <$pout>;
+	my $err = <$perr>;
+	waitpid($pid, 0);
+	[$out, $err, $?]
+}
+
+####################################################################################################
+# Tests related to the overall opustags executable, like the help message.
+# No Opus file is manipulated here.
+
+is_deeply(opustags(), ['', <<EOF, 256], 'no options is a failure');
+error: No arguments specified. Use -h for help.
+EOF
+
+my $help = opustags('--help');
+$help->[0] =~ /^([^\n]*+)/;
+my $version = $1;
+like($version, qr/^opustags version (\d+\.\d+\.\d+)/, 'get the version string');
+
+my $expected_help = <<"EOF";
+$version
+
+Usage: opustags --help
+       opustags [OPTIONS] FILE
+       opustags OPTIONS -i FILE...
+       opustags OPTIONS FILE -o FILE
+
+Options:
+  -h, --help                    print this help
+  -o, --output FILE             specify the output file
+  -i, --in-place                overwrite the input files
+  -y, --overwrite               overwrite the output file if it already exists
+  -a, --add FIELD=VALUE         add a comment
+  -d, --delete FIELD[=VALUE]    delete previously existing comments
+  -D, --delete-all              delete all the previously existing comments
+  -s, --set FIELD=VALUE         replace a comment
+  -S, --set-all                 import comments from standard input
+  -e, --edit                    edit tags interactively in VISUAL/EDITOR
+  --raw                         disable encoding conversion
+
+See the man page for extensive documentation.
+EOF
+
+is_deeply(opustags('--help'), [$expected_help, '', 0], '--help displays the help message');
+is_deeply(opustags('-h'), [$expected_help, '', 0], '-h displays the help message too');
+
+is_deeply(opustags('--derp'), ['', <<"EOF", 256], 'unrecognized option shows an error');
+error: Unrecognized option '--derp'.
+EOF
+
+is_deeply(opustags('../opustags'), ['', <<"EOF", 256], 'not an Ogg stream');
+../opustags: error: Input is not a valid Ogg file.
+EOF
+
+####################################################################################################
+# Test the main features of opustags on an Ogg Opus sample file.
+
+sub md5 {
+	my ($file) = @_;
+	open(my $fh, '<', $file) or return;
+	my $ctx = Digest::MD5->new;
+	$ctx->addfile($fh);
+	$ctx->hexdigest
+}
+
+is(md5('gobble.opus'), '111a483596ac32352fbce4d14d16abd2', 'the sample is the one we expect');
+is_deeply(opustags('gobble.opus'), [<<'EOF', '', 0], 'read the initial tags');
+encoder=Lavc58.18.100 libopus
+EOF
+
+unlink('out.opus');
+my $previous_umask = umask(0022);
+is_deeply(opustags(qw(gobble.opus -o out.opus)), ['', '', 0], 'copy the file without changes');
+is(md5('out.opus'), '111a483596ac32352fbce4d14d16abd2', 'the copy is faithful');
+is((stat 'out.opus')[2] & 0777, 0644, 'apply umask on new files');
+umask($previous_umask);
+
+# empty out.opus
+{ my $fh; open($fh, '>', 'out.opus') and close($fh) or die }
+is_deeply(opustags(qw(gobble.opus -o out.opus)), ['', <<'EOF', 256], 'refuse to override');
+gobble.opus: error: 'out.opus' already exists. Use -y to overwrite.
+EOF
+is(md5('out.opus'), 'd41d8cd98f00b204e9800998ecf8427e', 'the output wasn\'t written');
+
+is_deeply(opustags(qw(gobble.opus -o /dev/null)), ['', '', 0], 'write to /dev/null');
+
+chmod(0604, 'out.opus');
+is_deeply(opustags(qw(gobble.opus -o out.opus --overwrite)), ['', '', 0], 'overwrite');
+is(md5('out.opus'), '111a483596ac32352fbce4d14d16abd2', 'successfully overwritten');
+is((stat 'out.opus')[2] & 0777, 0604, 'overwriting preserves output file\'s mode');
+
+chmod(0700, 'out.opus');
+is_deeply(opustags(qw(--in-place out.opus -a A=B --add=A=C --add), "TITLE=Foo Bar",
+                   qw(--delete A --add TITLE=七面鳥 --set encoder=whatever -s 1=2 -s X=1 -a X=2 -s X=3)),
+          ['', '', 0], 'complex tag editing');
+is(md5('out.opus'), '66780307a6081523dc9040f3c47b0448', 'check the footprint');
+is((stat 'out.opus')[2] & 0777, 0700, 'in-place editing preserves file mode');
+
+is_deeply(opustags('out.opus'), [<<'EOF', '', 0], 'check the tags written');
+A=B
+A=C
+TITLE=Foo Bar
+TITLE=七面鳥
+encoder=whatever
+1=2
+X=1
+X=2
+X=3
+EOF
+
+is_deeply(opustags(qw(out.opus -d A -d foo -s X=4 -a TITLE=gobble -d title=七面鳥)), [<<'EOF', '', 0], 'dry editing');
+TITLE=Foo Bar
+encoder=whatever
+1=2
+X=4
+TITLE=gobble
+EOF
+is(md5('out.opus'), '66780307a6081523dc9040f3c47b0448', 'the file did not change');
+
+is_deeply(opustags(qw(-i out.opus -a fatal=yes -a FOO -a BAR)), ['', <<'EOF', 256], 'bad tag with --add');
+error: Comment does not contain an equal sign: FOO.
+EOF
+is(md5('out.opus'), '66780307a6081523dc9040f3c47b0448', 'the file did not change');
+
+is_deeply(opustags('out.opus', '-D', '-a', "X=foo\nbar\tquux"), [<<'END_OUT', <<'END_ERR', 0], 'control characters');
+X=foo
+bar	quux
+END_OUT
+warning: Some tags contain unsupported newline characters.
+warning: Some tags contain control characters.
+END_ERR
+
+is_deeply(opustags(qw(-i out.opus -s fatal=yes -s FOO -s BAR)), ['', <<'EOF', 256], 'bad tag with --set');
+error: Comment does not contain an equal sign: FOO.
+EOF
+is(md5('out.opus'), '66780307a6081523dc9040f3c47b0448', 'the file did not change');
+
+is_deeply(opustags(qw(out.opus --delete-all -a OK=yes)), [<<'EOF', '', 0], 'delete all');
+OK=yes
+EOF
+
+is_deeply(opustags(qw(out.opus --set-all -a A=B -s X=Z -d OK), {in => <<'END_IN'}), [<<'END_OUT', '', 0], 'set all');
+OK=yes again
+ARTIST=七面鳥
+
+A=A
+X=Y
+#IGNORE=COMMENTS
+END_IN
+OK=yes again
+ARTIST=七面鳥
+A=A
+X=Y
+A=B
+X=Z
+END_OUT
+
+is_deeply(opustags(qw(out.opus -S), {in => <<'END_IN'}), [<<'END_OUT', <<'END_ERR', 256], 'set all with bad tags');
+whatever
+wrong=yes
+END_IN
+END_OUT
+error: Malformed tag: whatever
+END_ERR
+
+sub slurp {
+	my ($filename) = @_;
+	local $/;
+	open(my $fh, '<', $filename);
+	binmode($fh);
+	my $data = <$fh>;
+	$data
+}
+
+my $data = slurp 'out.opus';
+is_deeply(opustags('-', '-o', '-', {in => $data, mode => ':raw'}), [$data, '', 0], 'read opus from stdin and write to stdout');
+
+unlink('out.opus');
+
+# Test --in-place
+unlink('out2.opus');
+copy('gobble.opus', 'out.opus');
+is_deeply(opustags(qw(out.opus --add BAR=baz -o out2.opus)), ['', '', 0], 'process multiple files with --in-place');
+is_deeply(opustags(qw(--in-place --add FOO=bar out.opus out2.opus)), ['', '', 0], 'process multiple files with --in-place');
+is(md5('out.opus'), '30ba30c4f236c09429473f36f8f861d2', 'the tags were added correctly (out.opus)');
+is(md5('out2.opus'), '0a4d20c287b2e46b26cb0eee353c2069', 'the tags were added correctly (out2.opus)');
+
+unlink('out.opus');
+unlink('out2.opus');
+
+####################################################################################################
+# Interactive edition
+
+$ENV{EDITOR} = 'sed -i -e y/aeiou/AEIOU/ `sleep 0.1`';
+is_deeply(opustags('gobble.opus', '-eo', "'screaming !'.opus"), ['', '', 0], 'edit a file with EDITOR');
+is(md5("'screaming !'.opus"), '56e85ccaa83a13c15576d75bbd6d835f', 'the tags were modified');
+
+$ENV{EDITOR} = 'true';
+is_deeply(opustags('-ie', "'screaming !'.opus"), ['', "Cancelling edition because the tags file was not modified.\n", 256], 'close -e without saving');
+is(md5("'screaming !'.opus"), '56e85ccaa83a13c15576d75bbd6d835f', 'the tags were not modified');
+
+$ENV{EDITOR} = 'false';
+is_deeply(opustags('-ie', "'screaming !'.opus"), ['', "'screaming !'.opus: error: Child process exited with 1\n", 256], 'editor exiting with an error');
+is(md5("'screaming !'.opus"), '56e85ccaa83a13c15576d75bbd6d835f', 'the tags were not modified');
+
+unlink("'screaming !'.opus");
+
+####################################################################################################
+# Test muxed streams
+
+system('ffmpeg -loglevel error -y -i gobble.opus -c copy -map 0:0 -map 0:0 -shortest muxed.ogg') == 0
+	or BAIL_OUT('could not create a muxed stream');
+
+is_deeply(opustags('muxed.ogg'), ['', <<'END_ERR', 256], 'muxed streams detection');
+muxed.ogg: error: Muxed streams are not supported yet.
+END_ERR
+
+unlink('muxed.ogg');
+
+####################################################################################################
+# Locale
+
+my $locale = 'en_US.iso88591';
+my @all_locales = split(' ', `locale -a`);
+
+SKIP: {
+skip "locale $locale is not present", 5 unless (any { $_ eq $locale } @all_locales);
+
+opustags(qw(gobble.opus -a TITLE=七面鳥 -a ARTIST=éàç -o out.opus -y));
+
+local $ENV{LC_ALL} = $locale;
+local $ENV{LANGUAGE} = '';
+
+is_deeply(opustags(qw(-S out.opus), {in => <<"END_IN", mode => ':raw'}), [<<"END_OUT", '', 0], 'set all in ISO-8859-1');
+T=\xef\xef\xf6
+END_IN
+T=\xef\xef\xf6
+END_OUT
+
+is_deeply(opustags('-i', 'out.opus', "--add=I=\xf9\xce", {mode => ':raw'}), ['', '', 0], 'write tags in ISO-8859-1');
+
+is_deeply(opustags('out.opus', {mode => ':raw'}), [<<"END_OUT", <<"END_ERR", 256], 'read tags in ISO-8859-1 with incompatible characters');
+encoder=Lavc58.18.100 libopus
+END_OUT
+out.opus: error: Invalid or incomplete multibyte or wide character. See --raw.
+END_ERR
+
+is_deeply(opustags(qw(out.opus -d TITLE -d ARTIST), {mode => ':raw'}), [<<"END_OUT", '', 0], 'read tags in ISO-8859-1');
+encoder=Lavc58.18.100 libopus
+I=\xf9\xce
+END_OUT
+
+$ENV{LC_ALL} = '';
+
+is_deeply(opustags('out.opus'), [<<"END_OUT", '', 0], 'read tags in UTF-8');
+encoder=Lavc58.18.100 libopus
+TITLE=七面鳥
+ARTIST=éàç
+I=ùÎ
+END_OUT
+
+unlink('out.opus');
+}
+
+####################################################################################################
+# Raw edition
+
+is_deeply(opustags(qw(-S gobble.opus -o out.opus --raw -a), "U=\xFE", {in => <<"END_IN", mode => ':raw'}), ['', '', 0], 'raw set-all with binary data');
+T=\xFF
+END_IN
+
+is_deeply(opustags(qw(out.opus --raw), { mode => ':raw' }), [<<"END_OUT", '', 0], 'raw read');
+T=\xFF
+U=\xFE
+END_OUT
+
+unlink('out.opus');

t/system.cc

@@ -0,0 +1,67 @@
+#include <opustags.h>
+#include "tap.h"
+
+#include <string.h>
+#include <unistd.h>
+
+void check_partial_files()
+{
+	static const char* result = "partial_file.test";
+	std::string name;
+	{
+		ot::partial_file bad_tmp;
+		is(bad_tmp.open("/dev/null"), ot::st::standard_error,
+		   "opening a device as a partial file fails");
+		is(bad_tmp.open(result), ot::st::ok,
+		   "opening a regular partial file works");
+		name = bad_tmp.name();
+		if (name.size() != strlen(result) + 12 ||
+		    name.compare(0, strlen(result), result) != 0)
+			throw failure("the temporary name is surprising: " + name);
+	}
+	is(access(name.c_str(), F_OK), -1, "expect the temporary file is deleted");
+
+	ot::partial_file good_tmp;
+	is(good_tmp.open(result), ot::st::ok, "open the partial file");
+	name = good_tmp.name();
+	is(good_tmp.commit(), ot::st::ok, "commit the result file");
+	is(access(name.c_str(), F_OK), -1, "expect the temporary file is deleted");
+	is(access(result, F_OK), 0, "expect the final result file");
+	is(remove(result), 0, "remove the result file");
+}
+
+void check_converter()
+{
+	const char* ephemere_iso = "\xc9\x70\x68\xe9\x6d\xe8\x72\x65";
+	ot::encoding_converter to_utf8("ISO_8859-1", "UTF-8");
+	ot::encoding_converter from_utf8("UTF-8", "ISO_8859-1//IGNORE");
+	std::string out;
+
+	ot::status rc = to_utf8(ephemere_iso, out);
+	is(rc, ot::st::ok, "conversion to UTF-8 is successful");
+	is(out, "Éphémère", "conversion to UTF-8 is correct");
+
+	rc = from_utf8("Éphémère", out);
+	is(rc, ot::st::ok, "conversion from UTF-8 is successful");
+	is(out, ephemere_iso, "conversion from UTF-8 is correct");
+
+	rc = from_utf8("\xFF\xFF", out);
+	is(rc, ot::st::badly_encoded, "conversion from bad UTF-8 fails");
+}
+
+void check_shell_esape()
+{
+	is(ot::shell_escape("foo"), "'foo'", "simple string");
+	is(ot::shell_escape("a'b"), "'a'\\''b'", "string with a simple quote");
+	is(ot::shell_escape("a!b"), "'a'\\!'b'", "string with a bang");
+	is(ot::shell_escape("a!b'c!d'e"), "'a'\\!'b'\\''c'\\!'d'\\''e'", "string with a bang");
+}
+
+int main(int argc, char **argv)
+{
+	plan(3);
+	run(check_partial_files, "test partial files");
+	run(check_converter, "test encoding converter");
+	run(check_shell_esape, "test shell escaping");
+	return 0;
+}

t/tap.h

@@ -0,0 +1,64 @@
+/**
+ * \file t/tap.h
+ *
+ * \brief
+ * Helpers for following the Test Anything Protocol.
+ *
+ * Its interface mimics Test::More from Perl:
+ * https://perldoc.perl.org/Test/More.html
+ *
+ * Unlike Test::More, a test failure raises an exception and aborts the whole subtest.
+ */
+
+#pragma once
+
+#include <exception>
+#include <iostream>
+
+inline namespace tap {
+
+struct failure : std::runtime_error {
+	failure(const std::string& what) : std::runtime_error(what) {}
+};
+
+template <typename F>
+static void run(F test, const char *name)
+{
+	bool ok = false;
+	try {
+		test();
+		ok = true;
+	} catch (failure& e) {
+		std::cerr << "# fail: " << e.what() << "\n";
+	}
+	std::cout << (ok ? "ok" : "not ok") << " - " << name << "\n";
+}
+
+void plan(int tests)
+{
+	std::cout << "1.." << tests << "\n";
+}
+
+template <typename T, typename U>
+void is(const T& got, const U& expected, const char* name)
+{
+	if (got != expected) {
+		std::cerr << "# got: " << got << "\n"
+		             "# expected: " << expected << "\n";
+		throw failure(name);
+	}
+}
+
+template <>
+void is(const ot::status& got, const ot::st& expected, const char* name)
+{
+	if (got.code != expected) {
+		if (got.code == ot::st::ok)
+			std::cerr << "# unexpected success\n";
+		else
+			std::cerr << "# unexpected error: " << got.message << "\n";
+		throw failure(name);
+	}
+}
+
+}

tests/actions_test.cc

@@ -1,169 +0,0 @@
-#include "actions.h"
-#include "catch.h"
-
-#include "ogg.h"
-#include "tags_handlers/insertion_tags_handler.h"
-#include "tags_handlers/stream_tags_handler.h"
-
-#include <fstream>
-#include <cstring>
-
-using namespace opustags;
-
-static bool same_streams(ogg::Decoder &a, ogg::Decoder &b)
-{
-    std::shared_ptr<ogg::Stream> sa, sb;
-    ogg_packet pa, pb;
-    int ra, rb;
-
-    for (;;) {
-        sa = a.read_page();
-        sb = b.read_page();
-        if (!sa && !sb)
-            break; // both reached the end at the same time
-        if (!sa || !sb)
-            return false; // one stream is shorter than the other
-        if (sa->stream.serialno != sb->stream.serialno)
-            return false;
-        for (;;) {
-            ra = ogg_stream_packetout(&sa->stream, &pa);
-            rb = ogg_stream_packetout(&sb->stream, &pb);
-            if (ra != rb)
-                return false;
-            else if (ra == 0)
-                break;
-            else if (ra < 0)
-                throw std::runtime_error("ogg_stream_packetout failed");
-            // otherwise we got a valid packet on both sides
-            if (pa.bytes != pb.bytes || pa.b_o_s != pb.b_o_s || pa.e_o_s != pb.e_o_s)
-                return false;
-            if (pa.granulepos != pb.granulepos || pa.packetno != pb.packetno)
-                return false;
-            if (memcmp(pa.packet, pb.packet, pa.bytes) != 0)
-                return false;
-        }
-    }
-    return true;
-}
-
-static bool same_files(std::istream &a, std::istream &b)
-{
-    static const size_t block = 1024;
-    char ba[block], bb[block];
-    while (a && b) {
-        a.read(ba, block);
-        b.read(bb, block);
-        if (a.gcount() != b.gcount())
-            return false;
-        if (memcmp(ba, bb, a.gcount()) != 0)
-            return false;
-    }
-    if (a || b)
-        return false; // one of them is shorter
-    return true;
-}
-
-TEST_CASE("editing an unknown stream should do nothing", "[actions]")
-{
-    std::ifstream in("../tests/samples/beep.ogg");
-    std::stringstream out;
-    ogg::Decoder dec(in);
-    ogg::Encoder enc(out);
-
-    StreamTagsHandler editor(StreamTagsHandler::ALL_STREAMS);
-    edit_tags(dec, enc, editor);
-
-    in.clear();
-    in.seekg(0, in.beg);
-    out.clear();
-    out.seekg(0, out.beg);
-    REQUIRE(same_files(in, out));
-}
-
-TEST_CASE("fake editing of an Opus stream should preserve the stream", "[actions]")
-{
-    std::ifstream in("../tests/samples/mystery-beep.ogg");
-    std::stringstream out;
-    ogg::Decoder dec(in);
-    ogg::Encoder enc(out);
-
-    StreamTagsHandler editor(StreamTagsHandler::ALL_STREAMS);
-    edit_tags(dec, enc, editor);
-
-    in.clear();
-    in.seekg(0, in.beg);
-    out.clear();
-    out.seekg(0, out.beg);
-    REQUIRE(same_files(in, out));
-}
-
-TEST_CASE("editing a specific stream", "[actions]")
-{
-    std::ifstream in("../tests/samples/mystery-beep.ogg");
-    std::stringstream out;
-
-    {
-        ogg::Decoder dec(in);
-        ogg::Encoder enc(out);
-        InsertionTagsHandler editor(3, "pwnd", "yes");
-        edit_tags(dec, enc, editor);
-    }
-
-    in.clear();
-    in.seekg(0, in.beg);
-    out.clear();
-    out.seekg(0, out.beg);
-
-    {
-        ogg::Decoder a(in);
-        ogg::Decoder b(out);
-        std::shared_ptr<ogg::Stream> s2[6];
-        for (int i = 0; i < 6; i++) {
-            // get the headers
-            a.read_page();
-            s2[i] = b.read_page();
-        }
-
-        REQUIRE(s2[0]->type == ogg::OPUS_STREAM);
-        REQUIRE(s2[1]->type == ogg::UNKNOWN_STREAM);
-        REQUIRE(s2[2]->type == ogg::OPUS_STREAM);
-        REQUIRE(!s2[0]->tags.contains("pwnd"));
-        REQUIRE(s2[2]->tags.get("pwnd") == "yes");
-
-        REQUIRE(same_streams(a, b));
-    }
-}
-
-class GetLanguages : public StreamTagsHandler {
-public:
-    GetLanguages() : StreamTagsHandler(StreamTagsHandler::ALL_STREAMS) {}
-    std::vector<std::string> languages;
-protected:
-    void list_impl(const Tags &tags) {
-        languages.push_back(tags.get("LANGUAGE"));
-    }
-};
-
-TEST_CASE("listing tags", "[actions]")
-{
-    std::ifstream in("../tests/samples/mystery-beep.ogg");
-    ogg::Decoder dec(in);
-    GetLanguages lister;
-    list_tags(dec, lister);
-
-    REQUIRE(lister.languages.size() == 2);
-    REQUIRE(lister.languages[0] == "und");
-    REQUIRE(lister.languages[1] == "und");
-}
-
-TEST_CASE("listing tags, full scan", "[actions]")
-{
-    std::ifstream in("../tests/samples/mystery-beep.ogg");
-    ogg::Decoder dec(in);
-    GetLanguages lister;
-    list_tags(dec, lister, true);
-
-    REQUIRE(lister.languages.size() == 2);
-    REQUIRE(lister.languages[0] == "und");
-    REQUIRE(lister.languages[1] == "und");
-}

tests/main.cc

@@ -1,2 +0,0 @@
-#define CATCH_CONFIG_MAIN
-#include "catch.h"

tests/ogg_test.cc

@@ -1,148 +0,0 @@
-#include "ogg.h"
-#include "catch.h"
-
-#include <fstream>
-
-using namespace opustags;
-
-TEST_CASE("decoding a single-stream Ogg Opus file", "[ogg]")
-{
-    std::ifstream src("../tests/samples/mystery.ogg");
-    ogg::Decoder dec(src);
-
-    std::shared_ptr<ogg::Stream> s = dec.read_page();
-    REQUIRE(s != nullptr);
-    REQUIRE(s->state == ogg::HEADER_READY);
-    REQUIRE(s->type == ogg::OPUS_STREAM);
-
-    std::shared_ptr<ogg::Stream> s2 = dec.read_page();
-    REQUIRE(s2 == s);
-    REQUIRE(s->state == ogg::TAGS_READY);
-    REQUIRE(s->type == ogg::OPUS_STREAM);
-    REQUIRE(s->tags.get("encoder") == "Lavc57.24.102 libopus");
-}
-
-TEST_CASE("decoding garbage", "[ogg]")
-{
-    std::ifstream src("Makefile");
-    ogg::Decoder dec(src);
-    REQUIRE_THROWS(dec.read_page());
-}
-
-TEST_CASE("decoding an Ogg Vorbis file", "[ogg]")
-{
-    std::ifstream src("../tests/samples/beep.ogg");
-    ogg::Decoder dec(src);
-
-    std::shared_ptr<ogg::Stream> s = dec.read_page();
-    REQUIRE(s != nullptr);
-    REQUIRE(s->state == ogg::HEADER_READY);
-    REQUIRE(s->type == ogg::UNKNOWN_STREAM);
-
-    s = dec.read_page();
-    REQUIRE(s != nullptr);
-    REQUIRE(s->state == ogg::RAW_READY);
-}
-
-TEST_CASE("decoding a multi-stream file", "[ogg]")
-{
-    std::ifstream src("../tests/samples/mystery-beep.ogg");
-    ogg::Decoder dec(src);
-    std::shared_ptr<ogg::Stream> first, second, third, s;
-
-    s = dec.read_page();
-    first = s;
-    REQUIRE(s != nullptr);
-    REQUIRE(s->state == ogg::HEADER_READY);
-    REQUIRE(s->type == ogg::OPUS_STREAM);
-
-    s = dec.read_page();
-    second = s;
-    REQUIRE(s != nullptr);
-    REQUIRE(s != first);
-    REQUIRE(s->state == ogg::HEADER_READY);
-    REQUIRE(s->type == ogg::UNKNOWN_STREAM);
-
-    s = dec.read_page();
-    third = s;
-    REQUIRE(s != nullptr);
-    REQUIRE(s != first);
-    REQUIRE(s != second);
-    REQUIRE(s->state == ogg::HEADER_READY);
-    REQUIRE(s->type == ogg::OPUS_STREAM);
-
-    s = dec.read_page();
-    REQUIRE(s == first);
-    REQUIRE(s->state == ogg::TAGS_READY);
-
-    s = dec.read_page();
-    REQUIRE(s == second);
-    REQUIRE(s->state == ogg::RAW_READY);
-
-    s = dec.read_page();
-    REQUIRE(s == third);
-    REQUIRE(s->state == ogg::TAGS_READY);
-}
-
-static void craft_stream(std::ostream &out, const std::string &tags_data)
-{
-    ogg::Encoder enc(out);
-    ogg_stream_state os;
-    ogg_page og;
-    ogg_packet op;
-    ogg_stream_init(&os, 0);
-
-    op.packet = reinterpret_cast<unsigned char*>(const_cast<char*>("OpusHead"));
-    op.bytes = 8;
-    op.b_o_s = 1;
-    op.e_o_s = 0;
-    op.granulepos = 0;
-    op.packetno = 0;
-    ogg_stream_packetin(&os, &op);
-    ogg_stream_flush(&os, &og);
-    enc.write_raw_page(og);
-
-    op.packet = reinterpret_cast<unsigned char*>(const_cast<char*>(tags_data.data()));
-    op.bytes = tags_data.size();
-    op.b_o_s = 0;
-    op.e_o_s = 1;
-    op.granulepos = 0;
-    op.packetno = 1;
-    ogg_stream_packetin(&os, &op);
-    ogg_stream_flush(&os, &og);
-    enc.write_raw_page(og);
-
-    ogg_stream_clear(&os);
-}
-
-const char *evil_tags =
-    "OpusTags"
-    "\x00\x00\x00\x00" "" /* vendor */
-    "\x01\x00\x00\x00" /* one comment */
-    "\xFA\x00\x00\x00" "TITLE=Evil"
-    /* ^ should be \x0A as the length of the comment is 10 */
-;
-
-TEST_CASE("decoding a malicious Ogg Opus file", "[ogg]")
-{
-    std::stringstream buf;
-    craft_stream(buf, std::string(evil_tags, 8 + 4 + 4 + 4 + 10));
-    buf.seekg(0, buf.beg);
-    ogg::Decoder dec(buf);
-
-    std::shared_ptr<ogg::Stream> s = dec.read_page();
-    REQUIRE(s != nullptr);
-    REQUIRE(s->state == ogg::HEADER_READY);
-    REQUIRE(s->type == ogg::OPUS_STREAM);
-
-    REQUIRE_THROWS(dec.read_page());
-}
-
-TEST_CASE("decoding a bad stream", "[ogg]")
-{
-    std::ifstream in("uioprheuio");
-    REQUIRE_THROWS(std::make_shared<ogg::Decoder>(in));
-}
-
-// Encoding is trickier, and might as well be done in actions_test.cc, given
-// opustags::edit_tags covers all of Encoder's regular code.

tests/options_test.cc

@@ -1,205 +0,0 @@
-#include "options.h"
-#include "catch.h"
-
-#include "tags_handlers/export_tags_handler.h"
-#include "tags_handlers/external_edit_tags_handler.h"
-#include "tags_handlers/import_tags_handler.h"
-#include "tags_handlers/insertion_tags_handler.h"
-#include "tags_handlers/listing_tags_handler.h"
-#include "tags_handlers/modification_tags_handler.h"
-#include "tags_handlers/removal_tags_handler.h"
-
-#include <memory>
-
-using namespace opustags;
-
-static std::unique_ptr<char[]> string_to_uptr(const std::string &str)
-{
-    auto ret = std::make_unique<char[]>(str.size() + 1);
-    for (size_t i = 0; i < str.size(); i++)
-        ret[i] = str[i];
-    ret[str.size()] = 0;
-    return ret;
-}
-
-static Options retrieve_options(
-    std::vector<std::string> args, bool fake_input_path = true)
-{
-    // need to pass non-const char*, but we got const objects. make copies
-    std::vector<std::unique_ptr<char[]>> arg_holders;
-    arg_holders.push_back(string_to_uptr("fake/path/to/program"));
-    for (size_t i = 0; i < args.size(); i++)
-        arg_holders.push_back(string_to_uptr(args[i]));
-    if (fake_input_path)
-        arg_holders.push_back(string_to_uptr("fake/path/to/input"));
-
-    auto plain_args = std::make_unique<char*[]>(arg_holders.size());
-    for (size_t i = 0; i < arg_holders.size(); i++)
-        plain_args[i] = arg_holders[i].get();
-
-    return parse_args(arg_holders.size(), plain_args.get());
-}
-
-// retrieve a specific TagsHandler from the CompositeTagsHandler in options
-template<typename T> static T *get_handler(
-    const Options &options, const size_t index)
-{
-    const auto handlers = options.tags_handler.get_handlers();
-    const auto handler = dynamic_cast<T*>(handlers.at(index).get());
-    REQUIRE(handler);
-    return handler;
-}
-
-TEST_CASE("option parsing", "[options]")
-{
-    SECTION("--help") {
-        REQUIRE(retrieve_options({"--help"}).show_help);
-        REQUIRE(retrieve_options({"-h"}).show_help);
-        REQUIRE(!retrieve_options({}).show_help);
-    }
-
-    SECTION("--version") {
-        REQUIRE(retrieve_options({"--version"}).show_version);
-        REQUIRE(retrieve_options({"-V"}).show_version);
-        REQUIRE(!retrieve_options({}).show_version);
-    }
-
-    SECTION("--overwrite") {
-        REQUIRE(retrieve_options({"--overwrite"}).overwrite);
-        REQUIRE(retrieve_options({"-y"}).overwrite);
-        REQUIRE(!retrieve_options({}).overwrite);
-    }
-
-    SECTION("--full") {
-        REQUIRE(retrieve_options({"--full"}).full);
-        REQUIRE(!retrieve_options({}).full);
-    }
-
-    SECTION("--in-place") {
-        REQUIRE(!retrieve_options({}).in_place);
-        REQUIRE(retrieve_options({}).path_out.empty());
-        REQUIRE(retrieve_options({"--in-place", "ABC"}, false).in_place);
-        REQUIRE(
-            retrieve_options({"--in-place", "ABC"}, false).path_out == ".otmp");
-        REQUIRE(retrieve_options({"--in-place"}).in_place);
-        REQUIRE(retrieve_options({"--in-place"}).path_out == ".otmp");
-        REQUIRE(retrieve_options({"--in-place=ABC"}).in_place);
-        REQUIRE(retrieve_options({"--in-place=ABC"}).path_out == "ABC");
-        REQUIRE(retrieve_options({"-i", "ABC"}, false).in_place);
-        REQUIRE(retrieve_options({"-i", "ABC"}, false).path_out == ".otmp");
-        REQUIRE(retrieve_options({"-i"}).in_place);
-        REQUIRE(retrieve_options({"-i"}).path_out == ".otmp");
-        REQUIRE(retrieve_options({"-iABC"}).in_place);
-        REQUIRE(retrieve_options({"-iABC"}).path_out == "ABC");
-    }
-
-    SECTION("input") {
-        REQUIRE_THROWS(retrieve_options({}, false));
-        REQUIRE_THROWS(retrieve_options({""}, false));
-        REQUIRE(retrieve_options({"input"}, false).path_in == "input");
-        REQUIRE_THROWS(retrieve_options({"input", "extra argument"}, false));
-    }
-
-    SECTION("--output") {
-        REQUIRE(retrieve_options({"--output", "ABC"}).path_out == "ABC");
-        REQUIRE(retrieve_options({"-o", "ABC"}).path_out == "ABC");
-        REQUIRE_THROWS(retrieve_options({"--output", ""}));
-        REQUIRE_THROWS(retrieve_options({"-o", ""}));
-    }
-
-    SECTION("--import") {
-        get_handler<ImportTagsHandler>(retrieve_options({"--import"}), 0);
-    }
-
-    SECTION("--export") {
-        get_handler<ExportTagsHandler>(retrieve_options({"--export"}), 0);
-    }
-
-    SECTION("--edit") {
-        get_handler<ExternalEditTagsHandler>(retrieve_options({"--edit"}), 0);
-        get_handler<ExternalEditTagsHandler>(retrieve_options({"-e"}), 0);
-    }
-
-    SECTION("--list") {
-        get_handler<ListingTagsHandler>(retrieve_options({"--list"}), 0);
-        get_handler<ListingTagsHandler>(retrieve_options({"-l"}), 0);
-        // TODO:
-        // test enabling / disabling colors, which should be
-        // contained inside the state of ListingTagsHandler
-        // TODO:
-        // it should be the default operation for readonly mode - test this too
-    }
-
-    SECTION("--delete-all") {
-        REQUIRE(get_handler<RemovalTagsHandler>(
-            retrieve_options({"--delete-all"}), 0)->get_tag_key().empty());
-
-        REQUIRE(get_handler<RemovalTagsHandler>(
-            retrieve_options({"-D"}), 0)->get_tag_key().empty());
-    }
-
-    SECTION("--delete") {
-        const auto opts = retrieve_options({"--delete", "A", "-d", "B"});
-        REQUIRE(get_handler<RemovalTagsHandler>(opts, 0)->get_tag_key() == "A");
-        REQUIRE(get_handler<RemovalTagsHandler>(opts, 1)->get_tag_key() == "B");
-        REQUIRE_THROWS(retrieve_options({"--delete", "invalid="}));
-    }
-
-    SECTION("--add") {
-        const auto opts = retrieve_options({"--add", "A=1", "-a", "B=2"});
-        const auto handler1 = get_handler<InsertionTagsHandler>(opts, 0);
-        const auto handler2 = get_handler<InsertionTagsHandler>(opts, 1);
-        REQUIRE(handler1->get_tag_key() == "A");
-        REQUIRE(handler1->get_tag_value() == "1");
-        REQUIRE(handler2->get_tag_key() == "B");
-        REQUIRE(handler2->get_tag_value() == "2");
-        REQUIRE_THROWS(retrieve_options({"--add", "invalid"}));
-    }
-
-    SECTION("--set") {
-        const auto opts = retrieve_options({"--set", "A=1", "-s", "B=2"});
-        const auto handler1 = get_handler<ModificationTagsHandler>(opts, 0);
-        const auto handler2 = get_handler<ModificationTagsHandler>(opts, 1);
-        REQUIRE(handler1->get_tag_key() == "A");
-        REQUIRE(handler1->get_tag_value() == "1");
-        REQUIRE(handler2->get_tag_key() == "B");
-        REQUIRE(handler2->get_tag_value() == "2");
-        REQUIRE_THROWS(retrieve_options({"--set", "invalid"}));
-    }
-
-    SECTION("--stream") {
-        // by default, use all the streams
-        REQUIRE(
-            get_handler<RemovalTagsHandler>(retrieve_options({"-d", "xyz"}), 0)
-            ->get_streamno() == StreamTagsHandler::ALL_STREAMS);
-
-        // ...unless the user supplies an option to use a specific stream
-        REQUIRE(
-            get_handler<RemovalTagsHandler>(
-                retrieve_options({"--stream", "1", "-d", "xyz"}), 0)
-            ->get_streamno() == 1);
-
-        // ...which can be combined multiple times
-        {
-            const auto opts = retrieve_options({
-                "--stream", "1",
-                "-d", "xyz",
-                "--stream", "2",
-                "-d", "abc"});
-            const auto handler1 = get_handler<RemovalTagsHandler>(opts, 0);
-            const auto handler2 = get_handler<RemovalTagsHandler>(opts, 1);
-            REQUIRE(handler1->get_streamno() == 1);
-            REQUIRE(handler2->get_streamno() == 2);
-        }
-
-        // ...or contain comma separated values
-        {
-            const auto opts = retrieve_options({
-                "--stream", "1,2", "-d", "xyz"});
-            const auto handler1 = get_handler<RemovalTagsHandler>(opts, 0);
-            const auto handler2 = get_handler<RemovalTagsHandler>(opts, 1);
-            REQUIRE(handler1->get_streamno() == 1);
-            REQUIRE(handler2->get_streamno() == 2);
-        }
-    }
-}

tests/tags_handlers/composite_tags_handler_test.cc

@@ -1,96 +0,0 @@
-#include "tags_handlers/composite_tags_handler.h"
-#include "catch.h"
-
-using namespace opustags;
-
-namespace
-{
-    struct DummyTagsHandler : ITagsHandler
-    {
-        DummyTagsHandler();
-
-        bool relevant(const int streamno) override;
-        void list(const int streamno, const Tags &) override;
-        bool edit(const int streamno, Tags &) override;
-        bool done() override;
-
-        bool relevant_ret, edit_ret, done_ret, list_fired;
-    };
-}
-
-DummyTagsHandler::DummyTagsHandler()
-    : relevant_ret(true), edit_ret(true), done_ret(true), list_fired(false)
-{
-}
-
-bool DummyTagsHandler::relevant(const int)
-{
-    return relevant_ret;
-}
-
-void DummyTagsHandler::list(const int, const Tags &)
-{
-    list_fired = true;
-}
-
-bool DummyTagsHandler::edit(const int, Tags &)
-{
-    return edit_ret;
-}
-
-bool DummyTagsHandler::done()
-{
-    return done_ret;
-}
-
-TEST_CASE("composite tags handler", "[tags_handlers]")
-{
-    auto handler1 = std::make_shared<DummyTagsHandler>();
-    auto handler2 = std::make_shared<DummyTagsHandler>();
-    CompositeTagsHandler composite_handler;
-    composite_handler.add_handler(handler1);
-    composite_handler.add_handler(handler2);
-
-    SECTION("relevance") {
-        const int dummy_streamno = 1;
-        handler1->relevant_ret = true;
-        handler2->relevant_ret = true;
-        REQUIRE(composite_handler.relevant(dummy_streamno));
-        handler1->relevant_ret = false;
-        REQUIRE(composite_handler.relevant(dummy_streamno));
-        handler2->relevant_ret = false;
-        REQUIRE(!composite_handler.relevant(dummy_streamno));
-    }
-
-    SECTION("listing") {
-        const int dummy_streamno = 1;
-        Tags dummy_tags;
-        REQUIRE(!handler1->list_fired);
-        REQUIRE(!handler2->list_fired);
-        composite_handler.list(dummy_streamno, dummy_tags);
-        REQUIRE(handler1->list_fired);
-        REQUIRE(handler2->list_fired);
-    }
-
-    SECTION("editing") {
-        const int dummy_streamno = 1;
-        Tags dummy_tags;
-        handler1->edit_ret = true;
-        handler2->edit_ret = true;
-        REQUIRE(composite_handler.edit(dummy_streamno, dummy_tags));
-        handler1->edit_ret = false;
-        REQUIRE(composite_handler.edit(dummy_streamno, dummy_tags));
-        handler2->edit_ret = false;
-        REQUIRE(!composite_handler.edit(dummy_streamno, dummy_tags));
-    }
-
-    SECTION("finish") {
-        handler1->done_ret = true;
-        handler2->done_ret = true;
-        REQUIRE(composite_handler.done());
-        handler1->done_ret = false;
-        REQUIRE(!composite_handler.done());
-        handler2->done_ret = false;
-        REQUIRE(!composite_handler.done());
-    }
-}

tests/tags_handlers/export_tags_handler_test.cc

@@ -1,23 +0,0 @@
-#include "tags_handlers/export_tags_handler.h"
-#include "catch.h"
-#include <sstream>
-
-using namespace opustags;
-
-TEST_CASE("export tags handler", "[tags_handlers]")
-{
-    std::stringstream ss;
-    ExportTagsHandler handler(ss);
-    handler.list(1, {{{"a", "value1"}, {"b", "value2"}}});
-    handler.list(2, {{{"c", "value3"}, {"d", "value4"}}});
-
-    REQUIRE(ss.str() == R"([Stream 1]
-a=value1
-b=value2
-
-[Stream 2]
-c=value3
-d=value4
-
-)");
-}

tests/tags_handlers/import_tags_handler_test.cc

@@ -1,142 +0,0 @@
-#include "tags_handlers/import_tags_handler.h"
-#include "catch.h"
-#include <sstream>
-
-using namespace opustags;
-
-TEST_CASE("import tags handler", "[tags_handlers]")
-{
-    SECTION("tags for streams not mentioned in import get emptied")
-    {
-        Tags tags = {{{"remove", "me"}}};
-        std::stringstream ss;
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().empty());
-    }
-
-    SECTION("streams that do not exist in the input file are ignored")
-    {
-        // TODO: rather than ignoring, at least print a warning
-        // requires #6
-
-        Tags tags;
-        std::stringstream ss;
-        ss << "[Stream 5]\nkey = value\n";
-        ImportTagsHandler handler(ss);
-        REQUIRE(!handler.edit(1, tags));
-        REQUIRE(tags.get_all().empty());
-    }
-
-    SECTION("adding unique tags")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << "[Stream 1]\nkey = value\nkey2 = value2\n";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().size() == 2);
-        REQUIRE(tags.get("key") == "value");
-        REQUIRE(tags.get("key2") == "value2");
-    }
-
-    SECTION("adding tags with the same key")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << "[Stream 1]\nkey = value1\nkey = value2\n";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().size() == 2);
-        REQUIRE(tags.get_all().at(0).key == "key");
-        REQUIRE(tags.get_all().at(1).key == "key");
-        REQUIRE(tags.get_all().at(0).value == "value1");
-        REQUIRE(tags.get_all().at(1).value == "value2");
-    }
-
-    SECTION("overwriting existing tags")
-    {
-        Tags tags = {{{"remove", "me"}}};
-        std::stringstream ss;
-        ss << "[Stream 1]\nkey = value\nkey2 = value2\n";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().size() == 2);
-        REQUIRE(tags.get("key") == "value");
-        REQUIRE(tags.get("key2") == "value2");
-    }
-
-    SECTION("various whitespace issues are worked around")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << " [StrEaM  1] \n\n  key = value  \nkey2=value2\n";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().size() == 2);
-        REQUIRE(tags.get("key") == "value");
-        REQUIRE(tags.get("key2") == "value2");
-    }
-
-    SECTION("not specifying stream assumes first stream")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << "key=value";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().size() == 1);
-        REQUIRE(tags.get("key") == "value");
-    }
-
-    SECTION("multiple streams")
-    {
-        Tags tags1;
-        Tags tags2;
-        std::stringstream ss;
-        ss << "[stream 1]\nkey=value\n[stream 2]\nkey2=value2";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags1));
-        REQUIRE(handler.edit(2, tags2));
-        REQUIRE(tags1.get_all().size() == 1);
-        REQUIRE(tags2.get_all().size() == 1);
-        REQUIRE(tags1.get("key") == "value");
-        REQUIRE(tags2.get("key2") == "value2");
-    }
-
-    SECTION("sections listed twice are concatenated")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << "[stream 1]\nkey=value\n"
-            "[stream 2]\nkey=irrelevant\n"
-            "[Stream 1]\nkey2=value2";
-        ImportTagsHandler handler(ss);
-        REQUIRE(handler.edit(1, tags));
-        REQUIRE(tags.get_all().size() == 2);
-        REQUIRE(tags.get("key") == "value");
-        REQUIRE(tags.get("key2") == "value2");
-    }
-
-    SECTION("weird input throws errors - malformed section headers")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << "[stream huh]\n";
-        REQUIRE_THROWS({
-            ImportTagsHandler handler(ss);
-            handler.edit(1, tags);
-        });
-    }
-
-    SECTION("weird input throws errors - malformed lines")
-    {
-        Tags tags;
-        std::stringstream ss;
-        ss << "tag huh\n";
-        REQUIRE_THROWS({
-            ImportTagsHandler handler(ss);
-            handler.edit(1, tags);
-        });
-    }
-}

tests/tags_handlers/insertion_tags_handler_test.cc

@@ -1,22 +0,0 @@
-#include "tags_handlers/insertion_tags_handler.h"
-#include "catch.h"
-
-using namespace opustags;
-
-TEST_CASE("insertion tags handler", "[tags_handlers]")
-{
-    Tags tags;
-    const auto streamno = 1;
-    const auto expected_tag_key = "tag_key";
-    const auto expected_tag_value = "tag_value";
-    InsertionTagsHandler handler(
-        streamno, expected_tag_key, expected_tag_value);
-
-    REQUIRE(handler.edit(streamno, tags));
-    REQUIRE(tags.get_all().size() == 1);
-    REQUIRE(tags.get(expected_tag_key) == expected_tag_value);
-
-    REQUIRE(handler.edit(streamno, tags));
-    REQUIRE(tags.get_all().size() == 2);
-    REQUIRE(tags.get(expected_tag_key) == expected_tag_value);
-}

tests/tags_handlers/listing_tags_handler_test.cc

@@ -1,22 +0,0 @@
-#include "tags_handlers/listing_tags_handler.h"
-#include "catch.h"
-#include <sstream>
-
-using namespace opustags;
-
-TEST_CASE("listing tags handler", "[tags_handlers]")
-{
-    const auto streamno = 1;
-
-    Tags tags;
-    tags.add("z", "value1");
-    tags.add("a", "value2");
-    tags.add("y", "value3");
-    tags.add("c", "value4");
-
-    std::stringstream ss;
-    ListingTagsHandler handler(streamno, ss);
-    handler.list(streamno, tags);
-
-    REQUIRE(ss.str() == "z=value1\na=value2\ny=value3\nc=value4\n");
-}

tests/tags_handlers/modification_tags_handler_test.cc

@@ -1,33 +0,0 @@
-#include "tags_handlers/modification_tags_handler.h"
-#include "catch.h"
-
-using namespace opustags;
-
-TEST_CASE("modification tags handler", "[tags_handlers]")
-{
-    const auto streamno = 1;
-    const auto first_tag_key = "tag_key";
-    const auto other_tag_key = "other_tag_key";
-    const auto dummy_value = "dummy";
-    const auto new_value = "dummy 2";
-
-    Tags tags;
-    tags.add(first_tag_key, dummy_value);
-
-    REQUIRE(tags.get_all().size() == 1);
-
-    // setting nonexistent keys adds them
-    ModificationTagsHandler handler1(streamno, other_tag_key, dummy_value);
-    REQUIRE(handler1.edit(streamno, tags));
-    REQUIRE(tags.get_all().size() == 2);
-    REQUIRE(tags.get(other_tag_key) == dummy_value);
-
-    // setting existing keys overrides their values
-    ModificationTagsHandler handler2(streamno, other_tag_key, new_value);
-    REQUIRE(handler2.edit(streamno, tags));
-    REQUIRE(tags.get_all().size() == 2);
-    REQUIRE(tags.get(other_tag_key) == new_value);
-
-    // setting existing keys reports no modifications if values are the same
-    REQUIRE(!handler2.edit(streamno, tags));
-}

tests/tags_handlers/removal_tags_handler_test.cc

@@ -1,43 +0,0 @@
-#include "tags_handlers/removal_tags_handler.h"
-#include "catch.h"
-
-using namespace opustags;
-
-TEST_CASE("removal tags handler", "[tags_handlers]")
-{
-    const auto streamno = 1;
-
-    SECTION("removing a single tag")
-    {
-        const auto expected_tag_key = "tag_key";
-        const auto other_tag_key = "other_tag_key";
-        const auto dummy_value = "dummy";
-        RemovalTagsHandler handler(streamno, expected_tag_key);
-
-        Tags tags;
-        tags.add(expected_tag_key, dummy_value);
-        tags.add(other_tag_key, dummy_value);
-
-        REQUIRE(tags.get_all().size() == 2);
-        REQUIRE(handler.edit(streamno, tags));
-        REQUIRE(tags.get_all().size() == 1);
-        REQUIRE(tags.contains(other_tag_key));
-        REQUIRE(!handler.edit(streamno, tags));
-    }
-
-    SECTION("removing all tags")
-    {
-        RemovalTagsHandler handler(streamno);
-
-        Tags tags;
-        tags.add("z", "value1");
-        tags.add("a", "value2");
-        tags.add("y", "value3");
-        tags.add("c", "value4");
-
-        REQUIRE(tags.get_all().size() == 4);
-        REQUIRE(handler.edit(streamno, tags));
-        REQUIRE(tags.get_all().size() == 0);
-        REQUIRE(!handler.edit(streamno, tags));
-    }
-}

tests/tags_handlers/stream_tags_handler_test.cc

@@ -1,92 +0,0 @@
-#include "tags_handlers/stream_tags_handler.h"
-#include "catch.h"
-
-using namespace opustags;
-
-namespace
-{
-    class DummyTagsHandler final : public StreamTagsHandler
-    {
-    public:
-        DummyTagsHandler(const int streamno);
-
-    protected:
-        void list_impl(const Tags &) override;
-        bool edit_impl(Tags &) override;
-
-    public:
-        bool list_fired, edit_fired;
-    };
-}
-
-DummyTagsHandler::DummyTagsHandler(const int streamno)
-    : StreamTagsHandler(streamno), list_fired(false), edit_fired(false)
-{
-}
-
-void DummyTagsHandler::list_impl(const Tags &)
-{
-    list_fired = true;
-}
-
-bool DummyTagsHandler::edit_impl(Tags &)
-{
-    edit_fired = true;
-    return true;
-}
-
-TEST_CASE("stream-based tags handler", "[tags_handlers]")
-{
-    SECTION("concrete stream") {
-        const auto relevant_stream_number = 1;
-        const auto irrelevant_stream_number = 2;
-        Tags dummy_tags;
-        DummyTagsHandler handler(relevant_stream_number);
-
-        SECTION("relevance") {
-            REQUIRE(!handler.relevant(irrelevant_stream_number));
-            REQUIRE(handler.relevant(relevant_stream_number));
-        }
-
-        SECTION("listing") {
-            handler.list(irrelevant_stream_number, dummy_tags);
-            REQUIRE(!handler.list_fired);
-            handler.list(relevant_stream_number, dummy_tags);
-            REQUIRE(handler.list_fired);
-        }
-
-        SECTION("Editing") {
-            REQUIRE(!handler.edit(irrelevant_stream_number, dummy_tags));
-            REQUIRE(!handler.edit_fired);
-            REQUIRE(handler.edit(relevant_stream_number, dummy_tags));
-            REQUIRE(handler.edit_fired);
-        }
-
-        SECTION("finish through listing") {
-            REQUIRE(!handler.edit(irrelevant_stream_number, dummy_tags));
-            REQUIRE(!handler.done());
-            REQUIRE(handler.edit(relevant_stream_number, dummy_tags));
-            REQUIRE(handler.done());
-        }
-
-        SECTION("finish through editing") {
-            handler.list(irrelevant_stream_number, dummy_tags);
-            REQUIRE(!handler.done());
-            handler.list(relevant_stream_number, dummy_tags);
-            REQUIRE(handler.done());
-        }
-    }
-
-    SECTION("any stream") {
-        Tags dummy_tags;
-        DummyTagsHandler handler(StreamTagsHandler::ALL_STREAMS);
-        REQUIRE(handler.relevant(1));
-        REQUIRE(handler.relevant(2));
-        REQUIRE(handler.relevant(3));
-        REQUIRE(!handler.done());
-        handler.list(1, dummy_tags);
-        REQUIRE(!handler.done());
-        handler.list(2, dummy_tags);
-        REQUIRE(!handler.done());
-    }
-}

tests/tags_test.cc

@@ -1,85 +0,0 @@
-#include "tags.h"
-#include "catch.h"
-
-using namespace opustags;
-
-TEST_CASE("tag manipulation", "[tags]")
-{
-    SECTION("basic operations") {
-        Tags tags;
-        REQUIRE(!tags.contains("a"));
-        tags.add("a", "1");
-        REQUIRE(tags.get("a") == "1");
-        REQUIRE(tags.contains("a"));
-        tags.remove("a");
-        REQUIRE(!tags.contains("a"));
-        REQUIRE_THROWS(tags.get("a"));
-    }
-
-    SECTION("clearing") {
-        Tags tags;
-        tags.add("a", "1");
-        tags.add("b", "2");
-        REQUIRE(tags.get_all().size() == 2);
-        tags.clear();
-        REQUIRE(tags.get_all().empty());
-    }
-
-    SECTION("maintaing order of insertions") {
-        Tags tags;
-        tags.add("z", "1");
-        tags.add("y", "2");
-        tags.add("x", "3");
-        tags.add("y", "4");
-
-        REQUIRE(tags.get_all().size() == 4);
-        REQUIRE(tags.get_all()[0].key == "z");
-        REQUIRE(tags.get_all()[1].key == "y");
-        REQUIRE(tags.get_all()[2].key == "x");
-        REQUIRE(tags.get_all()[3].key == "y");
-
-        tags.remove("z");
-        REQUIRE(tags.get_all().size() == 3);
-        REQUIRE(tags.get_all()[0].key == "y");
-        REQUIRE(tags.get_all()[1].key == "x");
-        REQUIRE(tags.get_all()[2].key == "y");
-
-        tags.add("gamma", "5");
-        REQUIRE(tags.get_all().size() == 4);
-        REQUIRE(tags.get_all()[0].key == "y");
-        REQUIRE(tags.get_all()[1].key == "x");
-        REQUIRE(tags.get_all()[2].key == "y");
-        REQUIRE(tags.get_all()[3].key == "gamma");
-    }
-
-    SECTION("key to multiple values") {
-        // ARTIST is set once per artist.
-        // https://www.xiph.org/vorbis/doc/v-comment.html
-        Tags tags;
-        tags.add("ARTIST", "You");
-        tags.add("ARTIST", "Me");
-        REQUIRE(tags.get_all().size() == 2);
-    }
-
-    SECTION("removing multivalues should remove all of them") {
-        Tags tags;
-        tags.add("ARTIST", "You");
-        tags.add("ARTIST", "Me");
-        tags.remove("ARTIST");
-        REQUIRE(tags.get_all().empty());
-    }
-
-    SECTION("tag parsing") {
-        Tag t = parse_tag("TITLE=Foo=Bar");
-        REQUIRE(t.key == "TITLE");
-        REQUIRE(t.value == "Foo=Bar");
-    }
-
-    SECTION("case insensitiveness for keys") {
-        Tags tags;
-        tags.add("TITLE", "Boop");
-        REQUIRE(tags.get("title") == "Boop");
-        tags.remove("titLE");
-        REQUIRE(tags.get_all().empty());
-    }
-}