new scripting system

core/src/duktape/duk_console.c

@@ -0,0 +1,185 @@
+/*
+ *  Minimal 'console' binding.
+ *
+ *  https://github.com/DeveloperToolsWG/console-object/blob/master/api.md
+ *  https://developers.google.com/web/tools/chrome-devtools/debug/console/console-reference
+ *  https://developer.mozilla.org/en/docs/Web/API/console
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include "duktape.h"
+#include "duk_console.h"
+
+/* XXX: Add some form of log level filtering. */
+
+/* XXX: Should all output be written via e.g. console.write(formattedMsg)?
+ * This would make it easier for user code to redirect all console output
+ * to a custom backend.
+ */
+
+/* XXX: Init console object using duk_def_prop() when that call is available. */
+
+static duk_ret_t duk__console_log_helper(duk_context *ctx, const char *error_name) {
+	duk_uint_t flags = (duk_uint_t) duk_get_current_magic(ctx);
+	FILE *output = (flags & DUK_CONSOLE_STDOUT_ONLY) ? stdout : stderr;
+	duk_idx_t n = duk_get_top(ctx);
+	duk_idx_t i;
+
+	duk_get_global_string(ctx, "console");
+	duk_get_prop_string(ctx, -1, "format");
+
+	for (i = 0; i < n; i++) {
+		if (duk_check_type_mask(ctx, i, DUK_TYPE_MASK_OBJECT)) {
+			/* Slow path formatting. */
+			duk_dup(ctx, -1);  /* console.format */
+			duk_dup(ctx, i);
+			duk_call(ctx, 1);
+			duk_replace(ctx, i);  /* arg[i] = console.format(arg[i]); */
+		}
+	}
+
+	duk_pop_2(ctx);
+
+	duk_push_string(ctx, " ");
+	duk_insert(ctx, 0);
+	duk_join(ctx, n);
+
+	if (error_name) {
+		duk_push_error_object(ctx, DUK_ERR_ERROR, "%s", duk_require_string(ctx, -1));
+		duk_push_string(ctx, "name");
+		duk_push_string(ctx, error_name);
+		duk_def_prop(ctx, -3, DUK_DEFPROP_FORCE | DUK_DEFPROP_HAVE_VALUE);  /* to get e.g. 'Trace: 1 2 3' */
+		duk_get_prop_string(ctx, -1, "stack");
+	}
+
+	fprintf(output, "%s\n", duk_to_string(ctx, -1));
+	if (flags & DUK_CONSOLE_FLUSH) {
+		fflush(output);
+	}
+	return 0;
+}
+
+static duk_ret_t duk__console_assert(duk_context *ctx) {
+	if (duk_to_boolean(ctx, 0)) {
+		return 0;
+	}
+	duk_remove(ctx, 0);
+
+	return duk__console_log_helper(ctx, "AssertionError");
+}
+
+static duk_ret_t duk__console_log(duk_context *ctx) {
+	return duk__console_log_helper(ctx, NULL);
+}
+
+static duk_ret_t duk__console_trace(duk_context *ctx) {
+	return duk__console_log_helper(ctx, "Trace");
+}
+
+static duk_ret_t duk__console_info(duk_context *ctx) {
+	return duk__console_log_helper(ctx, NULL);
+}
+
+static duk_ret_t duk__console_warn(duk_context *ctx) {
+	return duk__console_log_helper(ctx, NULL);
+}
+
+static duk_ret_t duk__console_error(duk_context *ctx) {
+	return duk__console_log_helper(ctx, "Error");
+}
+
+static duk_ret_t duk__console_dir(duk_context *ctx) {
+	/* For now, just share the formatting of .log() */
+	return duk__console_log_helper(ctx, 0);
+}
+
+static void duk__console_reg_vararg_func(duk_context *ctx, duk_c_function func, const char *name, duk_uint_t flags) {
+	duk_push_c_function(ctx, func, DUK_VARARGS);
+	duk_push_string(ctx, "name");
+	duk_push_string(ctx, name);
+	duk_def_prop(ctx, -3, DUK_DEFPROP_HAVE_VALUE | DUK_DEFPROP_FORCE);  /* Improve stacktraces by displaying function name */
+	duk_set_magic(ctx, -1, (duk_int_t) flags);
+	duk_put_prop_string(ctx, -2, name);
+}
+
+void duk_console_init(duk_context *ctx, duk_uint_t flags) {
+	duk_uint_t flags_orig;
+
+	/* If both DUK_CONSOLE_STDOUT_ONLY and DUK_CONSOLE_STDERR_ONLY where specified,
+	 * just turn off DUK_CONSOLE_STDOUT_ONLY and keep DUK_CONSOLE_STDERR_ONLY.
+	 */
+	if ((flags & DUK_CONSOLE_STDOUT_ONLY) && (flags & DUK_CONSOLE_STDERR_ONLY)) {
+	    flags &= ~DUK_CONSOLE_STDOUT_ONLY;
+	}
+	/* Remember the (possibly corrected) flags we received. */
+	flags_orig = flags;
+
+	duk_push_object(ctx);
+
+	/* Custom function to format objects; user can replace.
+	 * For now, try JX-formatting and if that fails, fall back
+	 * to ToString(v).
+	 */
+	duk_eval_string(ctx,
+		"(function (E) {"
+		    "return function format(v){"
+		        "try{"
+		            "return E('jx',v);"
+		        "}catch(e){"
+		            "return String(v);"  /* String() allows symbols, ToString() internal algorithm doesn't. */
+		        "}"
+		    "};"
+		"})(Duktape.enc)");
+	duk_put_prop_string(ctx, -2, "format");
+
+	flags = flags_orig;
+	if (!(flags & DUK_CONSOLE_STDOUT_ONLY) && !(flags & DUK_CONSOLE_STDERR_ONLY)) {
+	    /* No output indicators were specified; these levels go to stdout. */
+	    flags |= DUK_CONSOLE_STDOUT_ONLY;
+	}
+	duk__console_reg_vararg_func(ctx, duk__console_assert, "assert", flags);
+	duk__console_reg_vararg_func(ctx, duk__console_log, "log", flags);
+	duk__console_reg_vararg_func(ctx, duk__console_log, "debug", flags);  /* alias to console.log */
+	duk__console_reg_vararg_func(ctx, duk__console_trace, "trace", flags);
+	duk__console_reg_vararg_func(ctx, duk__console_info, "info", flags);
+
+	flags = flags_orig;
+	if (!(flags & DUK_CONSOLE_STDOUT_ONLY) && !(flags & DUK_CONSOLE_STDERR_ONLY)) {
+	    /* No output indicators were specified; these levels go to stderr. */
+	    flags |= DUK_CONSOLE_STDERR_ONLY;
+	}
+	duk__console_reg_vararg_func(ctx, duk__console_warn, "warn", flags);
+	duk__console_reg_vararg_func(ctx, duk__console_error, "error", flags);
+	duk__console_reg_vararg_func(ctx, duk__console_error, "exception", flags);  /* alias to console.error */
+	duk__console_reg_vararg_func(ctx, duk__console_dir, "dir", flags);
+
+	duk_put_global_string(ctx, "console");
+
+	/* Proxy wrapping: ensures any undefined console method calls are
+	 * ignored silently.  This was required specifically by the
+	 * DeveloperToolsWG proposal (and was implemented also by Firefox:
+	 * https://bugzilla.mozilla.org/show_bug.cgi?id=629607).  This is
+	 * apparently no longer the preferred way of implementing console.
+	 * When Proxy is enabled, whitelist at least .toJSON() to avoid
+	 * confusing JX serialization of the console object.
+	 */
+
+	if (flags & DUK_CONSOLE_PROXY_WRAPPER) {
+		/* Tolerate failure to initialize Proxy wrapper in case
+		 * Proxy support is disabled.
+		 */
+		(void) duk_peval_string_noresult(ctx,
+			"(function(){"
+			    "var D=function(){};"
+			    "var W={toJSON:true};"  /* whitelisted */
+			    "console=new Proxy(console,{"
+			        "get:function(t,k){"
+			            "var v=t[k];"
+			            "return typeof v==='function'||W[k]?v:D;"
+			        "}"
+			    "});"
+			"})();"
+		);
+	}
+}

core/src/duktape/duk_console.h

@@ -0,0 +1,29 @@
+#if !defined(DUK_CONSOLE_H_INCLUDED)
+#define DUK_CONSOLE_H_INCLUDED
+
+#include "duktape.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+/* Use a proxy wrapper to make undefined methods (console.foo()) no-ops. */
+#define DUK_CONSOLE_PROXY_WRAPPER  (1U << 0)
+
+/* Flush output after every call. */
+#define DUK_CONSOLE_FLUSH          (1U << 1)
+
+/* Send output to stdout only (default is mixed stdout/stderr). */
+#define DUK_CONSOLE_STDOUT_ONLY    (1U << 2)
+
+/* Send output to stderr only (default is mixed stdout/stderr). */
+#define DUK_CONSOLE_STDERR_ONLY    (1U << 3)
+
+/* Initialize the console system */
+extern void duk_console_init(duk_context *ctx, duk_uint_t flags);
+
+#if defined(__cplusplus)
+}
+#endif  /* end 'extern "C"' wrapper */
+
+#endif  /* DUK_CONSOLE_H_INCLUDED */