decoder/Control: make ReplayGainConfig const

src/decoder/DecoderControl.cxx

@@ -27,8 +27,10 @@
 
 #include <assert.h>
 
-DecoderControl::DecoderControl(Mutex &_mutex, Cond &_client_cond)
-	:mutex(_mutex), client_cond(_client_cond) {}
+DecoderControl::DecoderControl(Mutex &_mutex, Cond &_client_cond,
+			       const ReplayGainConfig &_replay_gain_config)
+	:mutex(_mutex), client_cond(_client_cond),
+	 replay_gain_config(_replay_gain_config) {}
 
 DecoderControl::~DecoderControl()
 {

src/decoder/DecoderControl.hxx

@@ -158,7 +158,7 @@ struct DecoderControl {
 	 */
 	MusicPipe *pipe;
 
-	ReplayGainConfig replay_gain_config;
+	const ReplayGainConfig replay_gain_config;
 	ReplayGainMode replay_gain_mode = ReplayGainMode::OFF;
 
 	float replay_gain_db = 0;
@@ -170,7 +170,8 @@ struct DecoderControl {
 	 * @param _mutex see #mutex
 	 * @param _client_cond see #client_cond
 	 */
-	DecoderControl(Mutex &_mutex, Cond &_client_cond);
+	DecoderControl(Mutex &_mutex, Cond &_client_cond,
+		       const ReplayGainConfig &_replay_gain_config);
 	~DecoderControl();
 
 	/**

src/player/Thread.cxx

@@ -345,7 +345,6 @@ Player::StartDecoder(MusicPipe &_pipe)
 	{
 		/* copy ReplayGain parameters to the decoder */
 		const ScopeLock protect(pc.mutex);
-		dc.replay_gain_config = pc.replay_gain_config;
 		dc.replay_gain_mode = pc.replay_gain_mode;
 	}
 
@@ -1164,7 +1163,7 @@ player_task(void *arg)
 
 	SetThreadName("player");
 
-	DecoderControl dc(pc.mutex, pc.cond);
+	DecoderControl dc(pc.mutex, pc.cond, pc.replay_gain_config);
 	decoder_thread_start(dc);
 
 	MusicBuffer buffer(pc.buffer_chunks);