DecoderList: add function decoder_plugins_supports_suffix()

src/DecoderList.cxx

@@ -118,43 +118,6 @@ static constexpr unsigned num_decoder_plugins =
 /** which plugins have been initialized successfully? */
 bool decoder_plugins_enabled[num_decoder_plugins];
 
-static unsigned
-decoder_plugin_index(const struct DecoderPlugin *plugin)
-{
-	unsigned i = 0;
-
-	while (decoder_plugins[i] != plugin)
-		++i;
-
-	return i;
-}
-
-static unsigned
-decoder_plugin_next_index(const struct DecoderPlugin *plugin)
-{
-	return plugin == 0
-		? 0 /* start with first plugin */
-		: decoder_plugin_index(plugin) + 1;
-}
-
-const struct DecoderPlugin *
-decoder_plugin_from_suffix(const char *suffix,
-			   const struct DecoderPlugin *plugin)
-{
-	if (suffix == nullptr)
-		return nullptr;
-
-	for (unsigned i = decoder_plugin_next_index(plugin);
-	     decoder_plugins[i] != nullptr; ++i) {
-		plugin = decoder_plugins[i];
-		if (decoder_plugins_enabled[i] &&
-		    plugin->SupportsSuffix(suffix))
-			return plugin;
-	}
-
-	return nullptr;
-}
-
 const struct DecoderPlugin *
 decoder_plugin_from_name(const char *name)
 {
@@ -213,3 +176,11 @@ void decoder_plugin_deinit_all(void)
 			plugin.Finish();
 		});
 }
+
+bool
+decoder_plugins_supports_suffix(const char *suffix)
+{
+	return decoder_plugins_try([suffix](const DecoderPlugin &plugin){
+			return plugin.SupportsSuffix(suffix);
+		});
+}

src/DecoderList.hxx

@@ -20,6 +20,8 @@
 #ifndef MPD_DECODER_LIST_HXX
 #define MPD_DECODER_LIST_HXX
 
+#include "Compiler.h"
+
 struct DecoderPlugin;
 
 extern const struct DecoderPlugin *const decoder_plugins[];
@@ -27,17 +29,6 @@ extern bool decoder_plugins_enabled[];
 
 /* interface for using plugins */
 
-/**
- * Find the next enabled decoder plugin which supports the specified suffix.
- *
- * @param suffix the file name suffix
- * @param plugin the previous plugin, or nullptr to find the first plugin
- * @return a plugin, or nullptr if none matches
- */
-const struct DecoderPlugin *
-decoder_plugin_from_suffix(const char *suffix,
-			   const struct DecoderPlugin *plugin);
-
 const struct DecoderPlugin *
 decoder_plugin_from_name(const char *name);
 
@@ -86,4 +77,12 @@ decoder_plugins_for_each_enabled(F f)
 			f(*decoder_plugins[i]);
 }
 
+/**
+ * Is there at least once #DecoderPlugin that supports the specified
+ * file name suffix?
+ */
+gcc_pure gcc_nonnull_all
+bool
+decoder_plugins_supports_suffix(const char *suffix);
+
 #endif

src/SongUpdate.cxx

@@ -107,7 +107,6 @@ bool
 Song::UpdateFileInArchive()
 {
 	const char *suffix;
-	const struct DecoderPlugin *plugin;
 
 	assert(IsFile());
 
@@ -117,8 +116,7 @@ Song::UpdateFileInArchive()
 	if (suffix == nullptr)
 		return false;
 
-	plugin = decoder_plugin_from_suffix(suffix, nullptr);
-	if (plugin == nullptr)
+	if (!decoder_plugins_supports_suffix(suffix))
 		return false;
 
 	delete tag;

src/UpdateSong.cxx

@@ -105,9 +105,7 @@ update_song_file(Directory &directory,
 		 const char *name, const char *suffix,
 		 const struct stat *st)
 {
-	const struct DecoderPlugin *plugin =
-		decoder_plugin_from_suffix(suffix, nullptr);
-	if (plugin == nullptr)
+	if (!decoder_plugins_supports_suffix(suffix))
 		return false;
 
 	update_song_file2(directory, name, st, suffix);