settings: add 'execute_on_player_state_change' option

NEWS

@@ -1,4 +1,5 @@
 ncmpcpp-0.8 (????-??-??)
+* Configuration variable 'execute_on_player_state_change' was added.
 
 ncmpcpp 0.7.4 (2016-04-17)
 * Fetching lyrics from lyricwiki.org was fixed.

doc/config

@@ -286,6 +286,15 @@
 ##
 #execute_on_song_change = ""
 #
+##
+## Note: Custom command that will be executed each
+## time player state changes. The environment variable
+## MPD_PLAYER_STATE is set to the current state (either
+## unknown, play, pause, or stop) for its duration.
+##
+#
+#execute_on_player_state_change = ""
+#
 #playlist_show_mpd_host = no
 #
 #playlist_show_remaining_time = no

doc/ncmpcpp.1

@@ -152,6 +152,11 @@ Format for songs' list displayed in columns.
 .B execute_on_song_change = COMMAND
 Shell command to execute on song change.
 .TP
+.B execute_on_player_state_change = COMMAND
+Shell command to execute on player state change. The environment variable
+.B MPD_PLAYER_STATE
+is set to the current state (either unknown, play, pause, or stop) for its duration.
+.TP
 .B playlist_show_mpd_host = yes/no
 If enabled, current MPD host will be shown in playlist.
 .TP

src/settings.cpp

@@ -375,6 +375,9 @@ bool Configuration::read(const std::vector<std::string> &config_paths, bool igno
 	p.add("execute_on_song_change", assign_default(
 		execute_on_song_change, ""
 	));
+	p.add("execute_on_player_state_change", assign_default(
+		execute_on_player_state_change, ""
+	));
 	p.add("playlist_show_mpd_host", yes_no(
 		playlist_show_mpd_host, false
 	));

src/settings.h

@@ -76,6 +76,7 @@ struct Configuration
 	std::string external_editor;
 	std::string system_encoding;
 	std::string execute_on_song_change;
+	std::string execute_on_player_state_change;
 	std::string lastfm_preferred_language;
 	std::wstring progressbar;
 	std::wstring visualizer_chars;
@@ -199,4 +200,3 @@ struct Configuration
 extern Configuration Config;
 
 #endif // NCMPCPP_SETTINGS_H
-

src/status.cpp

@@ -246,7 +246,7 @@ void Status::update(int event)
 	m_playlist_length = st.playlistLength();
 	m_total_time = st.totalTime();
 	m_volume = st.volume();
-	
+
 	if (event & MPD_IDLE_DATABASE)
 		Changes::database();
 	if (event & MPD_IDLE_STORED_PLAYLIST)
@@ -432,10 +432,10 @@ void Status::Changes::playlist(unsigned previous_version)
 		else // otherwise just add it to playlist
 			myPlaylist->main().addItem(std::move(*s));
 	}
-	
+
 	myPlaylist->reloadTotalLength();
 	myPlaylist->reloadRemaining();
-	
+
 	if (isVisible(myBrowser))
 		markSongsInPlaylist(myBrowser->main());
 	if (isVisible(mySearcher))
@@ -473,6 +473,24 @@ void Status::Changes::database()
 
 void Status::Changes::playerState()
 {
+	if (!Config.execute_on_player_state_change.empty())
+	{
+		auto stateToEnv = [](MPD::PlayerState st) -> const char * {
+			switch (st)
+			{
+			case MPD::psPlay:    return "play";
+			case MPD::psStop:    return "stop";
+			case MPD::psPause:   return "pause";
+			case MPD::psUnknown: return "unknown";
+			}
+			throw std::logic_error("unreachable");
+		};
+		GNUC_UNUSED int res;
+		setenv("MPD_PLAYER_STATE", stateToEnv(m_player_state), 1);
+		res = system(Config.execute_on_player_state_change.c_str());
+		unsetenv("MPD_PLAYER_STATE");
+	}
+
 	switch (m_player_state)
 	{
 		case MPD::psPlay:
@@ -503,7 +521,7 @@ void Status::Changes::playerState()
 		default:
 			break;
 	}
-	
+
 	std::string state = playerStateToString(m_player_state);
 	if (Config.design == Design::Alternative)
 	{
@@ -518,7 +536,7 @@ void Status::Changes::playerState()
 		else
 			*wFooter << NC::Format::Bold << state << NC::Format::NoBold;
 	}
-	
+
 	// needed for immediate display after starting
 	// player from stopped state or seeking
 	elapsedTime(false);
@@ -680,7 +698,7 @@ void Status::Changes::flags()
 {
 	if (!Config.header_visibility && Config.design == Design::Classic)
 		return;
-	
+
 	std::string switch_state;
 	switch (Config.design)
 	{
@@ -739,7 +757,7 @@ void Status::Changes::mixer()
 {
 	if (!Config.display_volume_level || (!Config.header_visibility && Config.design == Design::Classic))
 		return;
-	
+
 	switch (Config.design)
 	{
 		case Design::Classic: