Fix player race condition

Pressing any key before the player thread set mode to PLAYER_INITIALIZED
lead to a song skip and spawning of another player thread. The two
player threads were operating on the same variables/memory area,
resulting in a crash.

Adding a new player state (PLAYER_STARTING) and setting it _before_
invoking pthread_start should resolve this, 'cause the "if
PLAYER_FREED-branch" is not taken any more, ergo no second player thread
is started.

2 files changed, 14 insertions, 4 deletions

diff --git a/src/main.c b/src/main.c
index 82ed674..5428653 100644
--- a/src/main.c
+++ b/src/main.c
@@ -248,6 +248,9 @@ int main (int argc, char **argv) {
 						BarUiStartEventCmd (&settings, "songstart", curStation,
 								playlist, &player, PIANO_RET_OK);
 
+						/* prevent race condition, mode must _not_ be FREED if
+						 * thread has been started */
+						player.mode = PLAYER_STARTING;
 						/* start player */
 						pthread_create (&playerThread, NULL, BarPlayerThread,
 								&player);
diff --git a/src/player.h b/src/player.h
index 82a6cd5..249fc6f 100644
--- a/src/player.h
+++ b/src/player.h
@@ -49,10 +49,17 @@ struct audioPlayer {
 	size_t bufferRead;
 	size_t bytesReceived;
 
-	enum {PLAYER_FREED = 0, PLAYER_INITIALIZED, PLAYER_FOUND_ESDS,
-			PLAYER_AUDIO_INITIALIZED, PLAYER_FOUND_STSZ,
-			PLAYER_SAMPLESIZE_INITIALIZED, PLAYER_RECV_DATA,
-			PLAYER_FINISHED_PLAYBACK} mode;
+	enum {
+		PLAYER_FREED = 0, /* thread is not running */
+		PLAYER_STARTING, /* thread is starting */
+		PLAYER_INITIALIZED, /* decoder/waitress initialized */
+		PLAYER_FOUND_ESDS,
+		PLAYER_AUDIO_INITIALIZED, /* audio device opened */
+		PLAYER_FOUND_STSZ,
+		PLAYER_SAMPLESIZE_INITIALIZED,
+		PLAYER_RECV_DATA, /* playing track */
+		PLAYER_FINISHED_PLAYBACK
+	} mode;
 
 	PianoAudioFormat_t audioFormat;