output/snapcast: implement Pause()

This uncomments the code which had been present already in the first Snapcast commit (copied from the "httpd" output plugin), but I commented it because I did not know whether I needed to send silence samples to all Snapcast clients. As a side effect, this fixes playback when no Snapcast client is connected; this was broken because Pause() always returned a positive value when there were no clients. Closes https://github.com/MusicPlayerDaemon/MPD/issues/1310

output/snapcast: implement Pause()
9a21bdfd · Max Kellermann · 03f99dd2 · 9a21bdfd · 9a21bdfd
Commit 9a21bdfd authored Oct 31, 2021 by Max Kellermann
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Showing with 10 additions and 4 deletions

Internal.hxx src/output/plugins/snapcast/Internal.hxx +6 -0

SnapcastOutputPlugin.cxx src/output/plugins/snapcast/SnapcastOutputPlugin.cxx +4 -4

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--- a/src/output/plugins/snapcast/Internal.hxx
+++ b/src/output/plugins/snapcast/Internal.hxx
@@ -51,6 +51,12 @@ class SnapcastOutput final : AudioOutput, ServerSocket {
 	 */
 	bool open;

+	/**
+	 * Is the output current paused?  This is set by Pause() and
+	 * is cleared by the next Play() call.  It is used in Delay().
+	 */
+	bool pause;
+
 	InjectEvent inject_event;

 #ifdef HAVE_ZEROCONF

--- a/src/output/plugins/snapcast/SnapcastOutputPlugin.cxx
+++ b/src/output/plugins/snapcast/SnapcastOutputPlugin.cxx
@@ -161,6 +161,7 @@ SnapcastOutput::Open(AudioFormat &audio_format)
 	timer = new Timer(audio_format);

 	open = true;
+	pause = false;
 }

 void
@@ -213,7 +214,7 @@ SnapcastOutput::RemoveClient(SnapcastClient &client) noexcept
 std::chrono::steady_clock::duration
 SnapcastOutput::Delay() const noexcept
 {
-	if (!LockHasClients() /*&& pause*/) {
+	if (!LockHasClients() && pause) {
 		/* if there's no client and this output is paused,
 		   then Pause() will not do anything, it will not fill
 		   the buffer and it will not update the timer;
@@ -307,7 +308,7 @@ SnapcastOutput::SendTag(const Tag &tag)
 size_t
 SnapcastOutput::Play(const void *chunk, size_t size)
 {
-	//pause = false;
+	pause = false;

 	const auto now = std::chrono::steady_clock::now();

@@ -355,8 +356,7 @@ SnapcastOutput::Play(const void *chunk, size_t size)
 bool
 SnapcastOutput::Pause()
 {
-	// TODO: implement
-	//pause = true;
+	pause = true;

 	return true;
 }