Move TagsHandler to own file, make an interface

src/actions.cc

@@ -2,7 +2,7 @@
 
 using namespace opustags;
 
-void opustags::list_tags(ogg::Decoder &dec, TagsHandler &handler)
+void opustags::list_tags(ogg::Decoder &dec, ITagsHandler &handler)
 {
     ogg::Stream *s;
     while (!handler.done()) {
@@ -24,7 +24,8 @@ void opustags::list_tags(ogg::Decoder &dec, TagsHandler &handler)
     }
 }
 
-void opustags::edit_tags(ogg::Decoder &in, ogg::Encoder &out, TagsHandler &handler)
+void opustags::edit_tags(
+    ogg::Decoder &in, ogg::Encoder &out, ITagsHandler &handler)
 {
     ogg::Stream *s;
     while (true) {

src/actions.h

@@ -1,39 +1,10 @@
 #pragma once
 
-#include "tags.h"
 #include "ogg.h"
+#include "tags_handler.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.
-    struct TagsHandler
-    {
-
-        // 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).
-        bool relevant(int streamno) { return false; }
-
-        // The list method is called by list_tags every time it has
-        // successfully parsed an OpusTags header.
-        void list(int streamno, const Tags&) {}
-
-        // 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.
-        bool edit(int streamno, Tags&) { return false; }
-
-        // 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.
-        bool done() { return false; }
-
-    };
-
     // Decode a file and call the handler's list method every time a tags
     // header is read.
     //
@@ -43,7 +14,7 @@ namespace opustags {
     //   TagsLister lister(options);
     //   list_tags(dec, lister);
     //
-    void list_tags(ogg::Decoder&, TagsHandler&);
+    void list_tags(ogg::Decoder&, ITagsHandler &);
 
     // Forward the input data to the output stream, transforming tags on-the-go
     // with the handler's edit method.
@@ -56,6 +27,6 @@ namespace opustags {
     //   TagsEditor editor(options);
     //   edit_tags(dec, enc, editor);
     //
-    void edit_tags(ogg::Decoder &in, ogg::Encoder &out, TagsHandler&);
+    void edit_tags(ogg::Decoder &in, ogg::Encoder &out, ITagsHandler &);
 
 }

src/tags_handler.h

@@ -0,0 +1,35 @@
+#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;
+    };
+
+}