song/DetachedSong: copy the AudioFormat from LightSong

Enables the "Format" row in "playlistinfo" responses.

https://github.com/MusicPlayerDaemon/MPD/issues/1094

NEWS

@@ -1,6 +1,7 @@
 ver 0.23 (not yet released)
 * protocol
   - new command "getvol"
+  - show the audio format in "playlistinfo"
 * output
   - snapcast: new plugin
 

src/SongPrint.cxx

@@ -111,6 +111,9 @@ song_print_info(Response &r, const DetachedSong &song, bool base) noexcept
 	if (!IsNegative(song.GetLastModified()))
 		time_print(r, "Last-Modified", song.GetLastModified());
 
+	if (const auto &f = song.GetAudioFormat(); f.IsDefined())
+		r.Format("Format: %s\n", ToString(f).c_str());
+
 	tag_print_values(r, song.GetTag());
 
 	const auto duration = song.GetDuration();

src/SongSave.cxx

@@ -86,8 +86,7 @@ song_save(BufferedOutputStream &os, const DetachedSong &song)
 
 DetachedSong
 song_load(TextFile &file, const char *uri,
-	  std::string *target_r,
-	  AudioFormat *audio_format_r)
+	  std::string *target_r)
 {
 	DetachedSong song(uri);
 
@@ -113,14 +112,12 @@ song_load(TextFile &file, const char *uri,
 			if (target_r != nullptr)
 				*target_r = value;
 		} else if (StringIsEqual(line, "Format")) {
-			if (audio_format_r != nullptr) {
 			try {
-					*audio_format_r =
-						ParseAudioFormat(value, false);
+				song.SetAudioFormat(ParseAudioFormat(value,
+								     false));
 			} catch (...) {
 				/* ignore parser errors */
 			}
-			}
 		} else if (StringIsEqual(line, "Playlist")) {
 			tag.SetHasPlaylist(StringIsEqual(value, "yes"));
 		} else if (StringIsEqual(line, SONG_MTIME)) {

src/SongSave.hxx

@@ -44,7 +44,6 @@ song_save(BufferedOutputStream &os, const DetachedSong &song);
  */
 DetachedSong
 song_load(TextFile &file, const char *uri,
-	  std::string *target_r=nullptr,
-	  AudioFormat *audio_format_r=nullptr);
+	  std::string *target_r=nullptr);
 
 #endif

src/SongUpdate.cxx

@@ -153,9 +153,10 @@ DetachedSong::LoadFile(Path path)
 		return false;
 
 	TagBuilder tag_builder;
+	auto new_audio_format = AudioFormat::Undefined();
 
 	try {
-		if (!ScanFileTagsWithGeneric(path, tag_builder))
+		if (!ScanFileTagsWithGeneric(path, tag_builder, &new_audio_format))
 			return false;
 	} catch (...) {
 		// TODO: log or propagate I/O errors?
@@ -163,6 +164,7 @@ DetachedSong::LoadFile(Path path)
 	}
 
 	mtime = fi.GetModificationTime();
+	audio_format = new_audio_format;
 	tag_builder.Commit(tag);
 	return true;
 }
@@ -177,9 +179,11 @@ DetachedSong::Update()
 		return LoadFile(path_fs);
 	} else if (IsRemote()) {
 		TagBuilder tag_builder;
+		auto new_audio_format = AudioFormat::Undefined();
 
 		try {
-			if (!tag_stream_scan(uri.c_str(), tag_builder))
+			if (!tag_stream_scan(uri.c_str(), tag_builder,
+					     &new_audio_format))
 				return false;
 		} catch (...) {
 			// TODO: log or propagate I/O errors?
@@ -187,6 +191,7 @@ DetachedSong::Update()
 		}
 
 		mtime = std::chrono::system_clock::time_point::min();
+		audio_format = new_audio_format;
 		tag_builder.Commit(tag);
 		return true;
 	} else

src/db/plugins/simple/DirectorySave.cxx

@@ -168,15 +168,12 @@ directory_load(TextFile &file, Directory &directory)
 				throw FormatRuntimeError("Duplicate song '%s'", name);
 
 			std::string target;
-			auto audio_format = AudioFormat::Undefined();
 			auto detached_song = song_load(file, name,
-						       &target,
-						       &audio_format);
+						       &target);
 
 			auto song = std::make_unique<Song>(std::move(detached_song),
 							   directory);
 			song->target = std::move(target);
-			song->audio_format = audio_format;
 
 			directory.AddSong(std::move(song));
 		} else if ((p = StringAfterPrefix(line, PLAYLIST_META_BEGIN))) {

src/db/plugins/simple/Song.cxx

@@ -34,6 +34,7 @@ Song::Song(DetachedSong &&other, Directory &_parent) noexcept
 	 mtime(other.GetLastModified()),
 	 start_time(other.GetStartTime()),
 	 end_time(other.GetEndTime()),
+	 audio_format(other.GetAudioFormat()),
 	 filename(other.GetURI())
 {
 }

src/playlist/PlaylistSong.cxx

@@ -47,6 +47,9 @@ merge_song_metadata(DetachedSong &add, const DetachedSong &base) noexcept
 	if (add.GetEndTime().IsZero()) {
 		add.SetEndTime(base.GetEndTime());
 	}
+
+	if (!add.GetAudioFormat().IsDefined())
+		add.SetAudioFormat(base.GetAudioFormat());
 }
 
 static bool

src/song/DetachedSong.cxx

@@ -28,7 +28,8 @@ DetachedSong::DetachedSong(const LightSong &other) noexcept
 	 tag(other.tag),
 	 mtime(other.mtime),
 	 start_time(other.start_time),
-	 end_time(other.end_time) {}
+	 end_time(other.end_time),
+	 audio_format(other.audio_format) {}
 
 DetachedSong::operator LightSong() const noexcept
 {

src/song/DetachedSong.hxx

@@ -21,6 +21,7 @@
 #define MPD_DETACHED_SONG_HXX
 
 #include "tag/Tag.hxx"
+#include "pcm/AudioFormat.hxx"
 #include "Chrono.hxx"
 #include "util/Compiler.h"
 
@@ -79,6 +80,12 @@ class DetachedSong {
 	 */
 	SongTime end_time = SongTime::zero();
 
+	/**
+	 * The audio format of the song, if given by the decoder
+	 * plugin.  May be undefined if unknown.
+	 */
+	AudioFormat audio_format = AudioFormat::Undefined();
+
 public:
 	explicit DetachedSong(const char *_uri) noexcept
 		:uri(_uri) {}
@@ -231,6 +238,14 @@ public:
 	gcc_pure
 	SignedSongTime GetDuration() const noexcept;
 
+	const AudioFormat &GetAudioFormat() const noexcept {
+		return audio_format;
+	}
+
+	void SetAudioFormat(const AudioFormat &src) noexcept {
+		audio_format = src;
+	}
+
 	/**
 	 * Update the #tag and #mtime.
 	 *