output/Internal: remove mutex code from BeginPause(), IteratePause()

src/output/Internal.cxx

@@ -120,7 +120,6 @@ AudioOutput::Close(bool drain) noexcept
 void
 AudioOutput::BeginPause() noexcept
 {
-	const ScopeUnlock unlock(mutex);
 	ao_plugin_cancel(*this);
 }
 
@@ -128,7 +127,6 @@ bool
 AudioOutput::IteratePause() noexcept
 {
 	try {
-		const ScopeUnlock unlock(mutex);
 		return ao_plugin_pause(*this);
 	} catch (const std::runtime_error &e) {
 		FormatError(e, "\"%s\" [%s] failed to pause",

src/output/Thread.cxx

@@ -343,7 +343,11 @@ AudioOutputControl::InternalPlay() noexcept
 inline void
 AudioOutputControl::InternalPause() noexcept
 {
-	output->BeginPause();
+	{
+		const ScopeUnlock unlock(mutex);
+		output->BeginPause();
+	}
+
 	pause = true;
 
 	CommandFinished();
@@ -352,14 +356,24 @@ AudioOutputControl::InternalPause() noexcept
 		if (!WaitForDelay())
 			break;
 
-		if (!output->IteratePause()) {
+		bool success;
+		{
+			const ScopeUnlock unlock(mutex);
+			success = output->IteratePause();
+		}
+
+		if (!success) {
 			InternalClose(false);
 			break;
 		}
 	} while (command == Command::NONE);
 
 	pause = false;
-	output->EndPause();
+
+	{
+		const ScopeUnlock unlock(mutex);
+		output->EndPause();
+	}
 
 	skip_delay = true;
 }