decoder/Plugin: container_scan() returns AllocatedString

src/decoder/DecoderPlugin.hxx

@@ -26,6 +26,7 @@ struct ConfigBlock;
 class InputStream;
 struct TagHandler;
 class Path;
+template<typename T> class AllocatedString;
 
 /**
  * Opaque handle which the decoder plugin passes to the functions in
@@ -95,10 +96,8 @@ struct DecoderPlugin {
 	 * @return nullptr if there are no multiple files
 	 * a filename for every single track according to tnum (param 2)
 	 * do not include full pathname here, just the "virtual" file
-	 *
-	 * Free the return value with delete[].
 	 */
-	char* (*container_scan)(Path path_fs, const unsigned int tnum);
+	AllocatedString<char> (*container_scan)(Path path_fs, unsigned tnum);
 
 	/* last element in these arrays must always be a nullptr: */
 	const char *const*suffixes;

src/decoder/plugins/GmeDecoderPlugin.cxx

@@ -103,7 +103,7 @@ ParseContainerPath(Path path_fs)
 	return { path_fs.GetDirectoryName(), track - 1 };
 }
 
-static char *
+static AllocatedString<>
 gme_container_scan(Path path_fs, const unsigned int tnum)
 {
 	Music_Emu *emu;
@@ -123,7 +123,7 @@ gme_container_scan(Path path_fs, const unsigned int tnum)
 	const char *subtune_suffix = uri_get_suffix(path_fs.c_str());
 	if (tnum <= num_songs){
 		return FormatString(SUBTUNE_PREFIX "%03u.%s",
-				    tnum, subtune_suffix).Steal();
+				    tnum, subtune_suffix);
 	} else
 		return nullptr;
 }

src/decoder/plugins/SidplayDecoderPlugin.cxx

@@ -336,7 +336,7 @@ sidplay_scan_file(Path path_fs,
 	return true;
 }
 
-static char *
+static AllocatedString<>
 sidplay_container_scan(Path path_fs, const unsigned int tnum)
 {
 	SidTune tune(path_fs.c_str(), nullptr, true);
@@ -353,7 +353,7 @@ sidplay_container_scan(Path path_fs, const unsigned int tnum)
 	/* Construct container/tune path names, eg.
 		Delta.sid/tune_001.sid */
 	if(tnum<=info.songs) {
-		return FormatString(SUBTUNE_PREFIX "%03u.sid", tnum).Steal();
+		return FormatString(SUBTUNE_PREFIX "%03u.sid", tnum);
 	} else
 		return nullptr;
 }