new feature: support for fetching lyrics for currently playing song in background

doc/config

@@ -297,6 +297,8 @@
 #
 #follow_now_playing_lyrics = "no"
 #
+#fetch_lyrics_for_current_song_in_background = "no"
+#
 #store_lyrics_in_song_dir = "no"
 #
 ##

doc/keys

@@ -172,6 +172,8 @@
 #
 #key_toggle_lyrics_db = 'L'
 #
+#key_toggle_fetching_lyrics_for_current_song_in_background = 'F'
+#
 #key_go_to_containing_directory = 'G'
 #
 #key_go_to_media_library = '~'

doc/ncmpcpp.1

@@ -225,6 +225,9 @@ If enabled, seek time will increment by one each second of seeking.
 .B follow_now_playing_lyrics = yes/no
 If enabled, lyrics will be switched at song's change to currently playing one's (Note: this works only if you are viewing lyrics of item from Playlist).
 .TP
+.B fetch_lyrics_for_current_song_in_background = yes/no
+If enabled, each time song changes lyrics fetcher will be automatically run in background in attempt to download lyrics for currently playing song.
+.TP
 .B store_lyrics_in_song_dir = yes/no
 If enabled, lyrics will be saved in song's directory, otherwise in ~/.lyrics. Note that it needs properly set mpd_music_dir.
 .TP

src/curl_handle.cpp

@@ -37,8 +37,6 @@ namespace
 
 CURLcode Curl::perform(std::string &data, const std::string &URL, const std::string &referer, unsigned timeout)
 {
-	static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
-	pthread_mutex_lock(&lock);
 	CURLcode result;
 	CURL *c = curl_easy_init();
 	curl_easy_setopt(c, CURLOPT_URL, URL.c_str());
@@ -51,7 +49,6 @@ CURLcode Curl::perform(std::string &data, const std::string &URL, const std::str
 		curl_easy_setopt(c, CURLOPT_REFERER, referer.c_str());
 	result = curl_easy_perform(c);
 	curl_easy_cleanup(c);
-	pthread_mutex_unlock(&lock);
 	return result;
 }
 

src/help.cpp

@@ -222,6 +222,7 @@ void Help::GetKeybindings()
 #	ifdef HAVE_CURL_CURL_H
 	*w << DisplayKeys(Key.ArtistInfo)		<< "Show artist info\n";
 	*w << DisplayKeys(Key.ToggleLyricsDB)		<< "Toggle lyrics database\n";
+	*w << DisplayKeys(Key.ToggleFetchingLyricsInBackground) << "Toggle fetching lyrics for current song in background\n";
 #	endif // HAVE_CURL_CURL_H
 	*w << DisplayKeys(Key.Lyrics)			<< "Show/hide song's lyrics\n";
 	*w << "\n";

src/lyrics.cpp

@@ -48,12 +48,18 @@ using Global::MainStartY;
 using Global::myScreen;
 using Global::myOldScreen;
 
+std::string Lyrics::itsFolder = home_path + LYRICS_FOLDER;
+
+#ifdef HAVE_CURL_CURL_H
+LyricsFetcher **Lyrics::itsFetcher = 0;
+std::set<MPD::Song *> Lyrics::itsDownloaded;
+#endif // HAVE_CURL_CURL_H
+
 Lyrics *myLyrics = new Lyrics;
 
 void Lyrics::Init()
 {
 	w = new Scrollpad(0, MainStartY, COLS, MainHeight, "", Config.main_color, brNone);
-	itsFolder = home_path + LYRICS_FOLDER;
 	isInitialized = 1;
 }
 
@@ -107,6 +113,12 @@ void Lyrics::SwitchTo()
 	// take lyrics if they were downloaded
 	if (isReadyToTake)
 		Take();
+	
+	if (isDownloadInProgress || !itsDownloaded.empty())
+	{
+		ShowMessage("Lyrics are being downloaded...");
+		return;
+	}
 #	endif // HAVE_CURL_CURL_H
 	
 	if (const MPD::Song *s = myScreen->CurrentSong())
@@ -140,9 +152,55 @@ void Lyrics::SpacePressed()
 }
 
 #ifdef HAVE_CURL_CURL_H
-void *Lyrics::DownloadWrapper(void *this_ptr)
+void Lyrics::DownloadInBackground(const MPD::Song *s)
 {
-	return static_cast<Lyrics *>(this_ptr)->Download();
+	if (!s || s->GetArtist().empty() || s->GetTitle().empty())
+		return;
+	if (!s->Localized())
+		const_cast<MPD::Song *>(s)->Localize();
+	
+	std::string filename = GenerateFilename(*s);
+	std::ifstream f(filename.c_str());
+	if (f.is_open())
+	{
+		f.close();
+		return;
+	}
+	ShowMessage("Fetching lyrics for %s...", s->toString(Config.song_status_format_no_colors).c_str());
+	// we need to copy it and store separetely since this song may get deleted in the meantime.
+	MPD::Song *s_copy = new MPD::Song(*s);
+	itsDownloaded.insert(s_copy);
+	pthread_t t;
+	pthread_attr_t attr;
+	pthread_attr_init(&attr);
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+	pthread_create(&t, &attr, DownloadInBackgroundImpl, s_copy);
+}
+
+void *Lyrics::DownloadInBackgroundImpl(void *void_ptr)
+{
+	MPD::Song *s = static_cast<MPD::Song *>(void_ptr);
+	
+	std::string artist = Curl::escape(locale_to_utf_cpy(s->GetArtist()));
+	std::string title = Curl::escape(locale_to_utf_cpy(s->GetTitle()));
+	
+	LyricsFetcher::Result result;
+	bool fetcher_defined = itsFetcher && *itsFetcher;
+	for (LyricsFetcher **plugin = fetcher_defined ? itsFetcher : lyricsPlugins; *plugin != 0; ++plugin)
+	{
+		result = (*plugin)->fetch(artist, title);
+		if (result.first)
+			break;
+		if (fetcher_defined)
+			break;
+	}
+	if (result.first == true)
+		Save(GenerateFilename(*s), result.second);
+	
+	delete s;
+	itsDownloaded.erase(s);
+	
+	pthread_exit(0);
 }
 
 void *Lyrics::Download()
@@ -169,7 +227,7 @@ void *Lyrics::Download()
 	
 	if (result.first == true)
 	{
-		Save(result.second);
+		Save(itsFilename, result.second);
 		
 		utf_to_locale(result.second);
 		w->Clear();
@@ -181,37 +239,44 @@ void *Lyrics::Download()
 	isReadyToTake = 1;
 	pthread_exit(0);
 }
+
+void *Lyrics::DownloadWrapper(void *this_ptr)
+{
+	return static_cast<Lyrics *>(this_ptr)->Download();
+}
 #endif // HAVE_CURL_CURL_H
 
-void Lyrics::SetFilename()
+std::string Lyrics::GenerateFilename(const MPD::Song &s)
 {
+	std::string filename;
 	if (Config.store_lyrics_in_song_dir)
 	{
-		if (itsSong.isFromDB())
+		if (s.isFromDB())
 		{
-			itsFilename = Config.mpd_music_dir;
+			filename = Config.mpd_music_dir;
-			itsFilename += "/";
+			filename += "/";
-			itsFilename += itsSong.GetFile();
+			filename += s.GetFile();
 		}
 		else
-			itsFilename = itsSong.GetFile();
+			filename = s.GetFile();
 		// replace song's extension with .txt
-		size_t dot = itsFilename.rfind('.');
+		size_t dot = filename.rfind('.');
 		assert(dot != std::string::npos);
-		itsFilename.resize(dot);
+		filename.resize(dot);
-		itsFilename += ".txt";
+		filename += ".txt";
 	}
 	else
 	{
-		std::string file = locale_to_utf_cpy(itsSong.GetArtist());
+		std::string file = locale_to_utf_cpy(s.GetArtist());
 		file += " - ";
-		file += locale_to_utf_cpy(itsSong.GetTitle());
+		file += locale_to_utf_cpy(s.GetTitle());
 		file += ".txt";
 		EscapeUnallowedChars(file);
-		itsFilename = itsFolder;
+		filename = itsFolder;
-		itsFilename += "/";
+		filename += "/";
-		itsFilename += file;
+		filename += file;
 	}
+	return filename;
 }
 
 void Lyrics::Load()
@@ -225,7 +290,7 @@ void Lyrics::Load()
 	assert(!itsSong.GetTitle().empty());
 	
 	itsSong.Localize();
-	SetFilename();
+	itsFilename = GenerateFilename(itsSong);
 	
 	mkdir(itsFolder.c_str()
 #	ifndef WIN32
@@ -292,9 +357,9 @@ void Lyrics::Edit()
 }
 
 #ifdef HAVE_CURL_CURL_H
-void Lyrics::Save(const std::string &lyrics)
+void Lyrics::Save(const std::string &filename, const std::string &lyrics)
 {
-	std::ofstream output(itsFilename.c_str());
+	std::ofstream output(filename.c_str());
 	if (output.is_open())
 	{
 		output << lyrics;

src/lyrics.h

@@ -33,7 +33,7 @@ class Lyrics : public Screen<Scrollpad>
 	public:
 		Lyrics() : ReloadNP(0),
 #		ifdef HAVE_CURL_CURL_H
-		isReadyToTake(0), isDownloadInProgress(0), itsFetcher(0),
+		isReadyToTake(0), isDownloadInProgress(0),
 #		endif // HAVE_CURL_CURL_H
 		itsScrollBegin(0) { }
 		
@@ -53,8 +53,10 @@ class Lyrics : public Screen<Scrollpad>
 		
 		void Edit();
 		void Refetch();
+		
 #		ifdef HAVE_CURL_CURL_H
-		void ToggleFetcher();
+		static void ToggleFetcher();
+		static void DownloadInBackground(const MPD::Song *s);
 #		endif // HAVE_CURL_CURL_H
 		
 		bool ReloadNP;
@@ -65,25 +67,29 @@ class Lyrics : public Screen<Scrollpad>
 	private:
 		void Load();
 		
-		void SetFilename();
-		std::string itsFilename;
-		std::string itsFolder;
-		
 #		ifdef HAVE_CURL_CURL_H
+		static void *DownloadInBackgroundImpl(void *);
+		// storage for songs for which lyrics are being downloaded at the moment
+		static std::set<MPD::Song *> itsDownloaded;
+		
 		void *Download();
 		static void *DownloadWrapper(void *);
-		
+		static void Save(const std::string &filename, const std::string &lyrics);
-		void Save(const std::string &lyrics);
 		
 		void Take();
 		bool isReadyToTake;
 		bool isDownloadInProgress;
 		pthread_t itsDownloader;
-		LyricsFetcher **itsFetcher;
+		
+		static LyricsFetcher **itsFetcher;
 #		endif // HAVE_CURL_CURL_H
 		
 		size_t itsScrollBegin;
 		MPD::Song itsSong;
+		std::string itsFilename;
+		
+		static std::string itsFolder;
+		static std::string GenerateFilename(const MPD::Song &s);
 };
 
 extern Lyrics *myLyrics;

src/ncmpcpp.cpp

@@ -1432,6 +1432,11 @@ int main(int argc, char *argv[])
 		{
 			myLyrics->ToggleFetcher();
 		}
+		else if (Keypressed(input, Key.ToggleFetchingLyricsInBackground))
+		{
+			Config.fetch_lyrics_in_background = !Config.fetch_lyrics_in_background;
+			ShowMessage("Fetching lyrics for currently playing song in background: %s", Config.fetch_lyrics_in_background ? "On" : "Off");
+		}
 #		endif // HAVE_CURL_CURL_H
 		else if (Keypressed(input, Key.ToggleAutoCenter))
 		{

src/settings.cpp

@@ -251,6 +251,7 @@ void NcmpcppKeys::SetDefaults()
 	ToggleInterface[0] = '\\';
 	ToggleSeparatorsInPlaylist[0] = '!';
 	ToggleLyricsDB[0] = 'L';
+	ToggleFetchingLyricsInBackground[0] = 'F';
 	GoToParentDir[0] = KEY_BACKSPACE;
 	SwitchTagTypeList[0] = '`';
 	Quit[0] = 'q';
@@ -339,6 +340,7 @@ void NcmpcppKeys::SetDefaults()
 	ToggleInterface[1] = NullKey;
 	ToggleSeparatorsInPlaylist[1] = NullKey;
 	ToggleLyricsDB[1] = NullKey;
+	ToggleFetchingLyricsInBackground[1] = NullKey;
 	GoToParentDir[1] = 127;
 	SwitchTagTypeList[1] = NullKey;
 	Quit[1] = 'Q';
@@ -404,6 +406,7 @@ void NcmpcppConfig::SetDefaults()
 	albums_in_tag_editor = false;
 	incremental_seeking = true;
 	now_playing_lyrics = false;
+	fetch_lyrics_in_background = false;
 	local_browser_show_hidden_files = false;
 	search_in_db = true;
 	display_screens_numbers_on_start = true;
@@ -628,6 +631,8 @@ void NcmpcppKeys::Read()
 				GetKeys(key, ToggleSeparatorsInPlaylist);
 			else if (key.find("key_toggle_lyrics_db ") != std::string::npos)
 				GetKeys(key, ToggleLyricsDB);
+			else if (key.find("key_toggle_fetching_lyrics_for_current_song_in_background ") != std::string::npos)
+				GetKeys(key, ToggleFetchingLyricsInBackground);
 			else if (key.find("key_go_to_containing_directory ") != std::string::npos)
 				GetKeys(key, GoToContainingDir);
 			else if (key.find("key_go_to_media_library ") != std::string::npos)
@@ -987,6 +992,10 @@ void NcmpcppConfig::Read()
 			{
 				now_playing_lyrics = v == "yes";
 			}
+			else if (cl.find("fetch_lyrics_for_current_song_in_background") != std::string::npos)
+			{
+				fetch_lyrics_in_background = v == "yes";
+			}
 			else if (cl.find("ncmpc_like_songs_adding") != std::string::npos)
 			{
 				ncmpc_like_songs_adding = v == "yes";

src/settings.h

@@ -142,6 +142,7 @@ struct NcmpcppKeys
 	int ToggleInterface[2];
 	int ToggleSeparatorsInPlaylist[2];
 	int ToggleLyricsDB[2];
+	int ToggleFetchingLyricsInBackground[2];
 	int GoToParentDir[2];
 	int SwitchTagTypeList[2];
 	int Quit[2];
@@ -227,6 +228,7 @@ struct NcmpcppConfig
 	bool albums_in_tag_editor;
 	bool incremental_seeking;
 	bool now_playing_lyrics;
+	bool fetch_lyrics_in_background;
 	bool local_browser_show_hidden_files;
 	bool search_in_db;
 	bool display_screens_numbers_on_start;

src/status.cpp

@@ -401,6 +401,11 @@ void NcmpcppStatusChanged(MPD::Connection *, MPD::StatusChanges changed, void *)
 			if (!Config.execute_on_song_change.empty())
 				system(Config.execute_on_song_change.c_str());
 			
+#			ifdef HAVE_CURL_CURL_H
+			if (Config.fetch_lyrics_in_background)
+				Lyrics::DownloadInBackground(myPlaylist->NowPlayingSong());
+#			endif // HAVE_CURL_CURL_H
+			
 			if (Mpd.isPlaying() && !(np = Mpd.GetCurrentSong()).Empty())
 				WindowTitle(utf_to_locale_cpy(np.toString(Config.song_window_title_format)));