output/Control: add another Cond attribute, replacing audio_output_client_notify

src/output/Control.cxx

@@ -22,7 +22,6 @@
 #include "Filtered.hxx"
 #include "Domain.hxx"
 #include "mixer/MixerControl.hxx"
-#include "notify.hxx"
 #include "filter/plugins/ReplayGainFilterPlugin.hxx"
 #include "config/Block.hxx"
 #include "Log.hxx"
@@ -35,8 +34,6 @@
     automatically reopening the device */
 static constexpr PeriodClock::Duration REOPEN_AFTER = std::chrono::seconds(10);
 
-struct notify audio_output_client_notify;
-
 AudioOutputControl::AudioOutputControl(std::unique_ptr<FilteredAudioOutput> _output,
 				       AudioOutputClient &_client) noexcept
 	:output(std::move(_output)), client(_client),
@@ -116,10 +113,8 @@ AudioOutputControl::LockToggleEnabled() noexcept
 void
 AudioOutputControl::WaitForCommand() noexcept
 {
-	while (!IsCommandFinished()) {
+	while (!IsCommandFinished())
-		const ScopeUnlock unlock(mutex);
+		client_cond.wait(mutex);
-		audio_output_client_notify.Wait();
-	}
 }
 
 void

src/output/Control.hxx

@@ -93,6 +93,12 @@ class AudioOutputControl {
 	 */
 	Cond wake_cond;
 
+	/**
+	 * This condition object signals #command completion to the
+	 * client.
+	 */
+	Cond client_cond;
+
 	/**
 	 * Additional data for #command.  Protected by #mutex.
 	 */

src/output/Filtered.hxx

@@ -228,12 +228,6 @@ public:
 	}
 };
 
-/**
- * Notify object used by the thread's client, i.e. we will send a
- * notify signal to this object, expecting the caller to wait on it.
- */
-extern struct notify audio_output_client_notify;
-
 /**
  * Throws #std::runtime_error on error.
  */

src/output/MultipleOutputs.cxx

@@ -26,7 +26,6 @@
 #include "config/Block.hxx"
 #include "config/ConfigGlobal.hxx"
 #include "config/ConfigOption.hxx"
-#include "notify.hxx"
 #include "util/RuntimeError.hxx"
 
 #include <stdexcept>
@@ -155,23 +154,14 @@ MultipleOutputs::EnableDisable()
 	}
 }
 
-bool
+void
-MultipleOutputs::AllFinished() const noexcept
+MultipleOutputs::WaitAll() noexcept
 {
 	for (auto *ao : outputs) {
 		const std::lock_guard<Mutex> protect(ao->mutex);
 		if (ao->IsBusy())
-			return false;
+			ao->WaitForCommand();
 	}
-
-	return true;
-}
-
-void
-MultipleOutputs::WaitAll() noexcept
-{
-	while (!AllFinished())
-		audio_output_client_notify.Wait();
 }
 
 void

src/output/MultipleOutputs.hxx

@@ -145,12 +145,9 @@ public:
 
 private:
 	/**
-	 * Determine if all (active) outputs have finished the current
+	 * Wait until all (active) outputs have finished the current
 	 * command.
 	 */
-	gcc_pure
-	bool AllFinished() const noexcept;
-
 	void WaitAll() noexcept;
 
 	/**

src/output/Thread.cxx

@@ -22,7 +22,6 @@
 #include "Filtered.hxx"
 #include "Client.hxx"
 #include "Domain.hxx"
-#include "notify.hxx"
 #include "mixer/MixerInternal.hxx"
 #include "thread/Util.hxx"
 #include "thread/Slack.hxx"
@@ -41,8 +40,7 @@ AudioOutputControl::CommandFinished() noexcept
 	assert(command != Command::NONE);
 	command = Command::NONE;
 
-	const ScopeUnlock unlock(mutex);
+	client_cond.signal();
-	audio_output_client_notify.Signal();
 }
 
 inline void