output/Control: add struct AudioOutputControl

Will move attributes from struct AudioOutput that are specific to the
OutputThread.  The new struct AudioOutputControl is a holder for the
AudioOutput pointer.

This prepares for making the output list more dynamic, to allow moving
outputs to between partitions.

9 files changed, 325 insertions, 59 deletions

diff --git a/src/mixer/MixerAll.cxx b/src/mixer/MixerAll.cxx
index e9bcde93a..cb50c3418 100644
--- a/src/mixer/MixerAll.cxx
+++ b/src/mixer/MixerAll.cxx
@@ -31,12 +31,12 @@
 #include <assert.h>
 
 static int
-output_mixer_get_volume(const AudioOutput &ao)
+output_mixer_get_volume(const AudioOutputControl &ao)
 {
-	if (!ao.enabled)
+	if (!ao.IsEnabled())
 		return -1;
 
-	Mixer *mixer = ao.mixer;
+	auto *mixer = ao.GetMixer();
 	if (mixer == nullptr)
 		return -1;
 
@@ -56,7 +56,7 @@ MultipleOutputs::GetVolume() const
 	unsigned ok = 0;
 	int total = 0;
 
-	for (auto ao : outputs) {
+	for (auto *ao : outputs) {
 		int volume = output_mixer_get_volume(*ao);
 		if (volume >= 0) {
 			total += volume;
@@ -71,14 +71,14 @@ MultipleOutputs::GetVolume() const
 }
 
 static bool
-output_mixer_set_volume(AudioOutput &ao, unsigned volume)
+output_mixer_set_volume(AudioOutputControl &ao, unsigned volume)
 {
 	assert(volume <= 100);
 
-	if (!ao.enabled)
+	if (!ao.IsEnabled())
 		return false;
 
-	Mixer *mixer = ao.mixer;
+	auto *mixer = ao.GetMixer();
 	if (mixer == nullptr)
 		return false;
 
@@ -99,7 +99,7 @@ MultipleOutputs::SetVolume(unsigned volume)
 	assert(volume <= 100);
 
 	bool success = false;
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		success = output_mixer_set_volume(*ao, volume)
 			|| success;
 
@@ -107,12 +107,12 @@ MultipleOutputs::SetVolume(unsigned volume)
 }
 
 static int
-output_mixer_get_software_volume(const AudioOutput &ao)
+output_mixer_get_software_volume(const AudioOutputControl &ao)
 {
-	if (!ao.enabled)
+	if (!ao.IsEnabled())
 		return -1;
 
-	Mixer *mixer = ao.mixer;
+	auto *mixer = ao.GetMixer();
 	if (mixer == nullptr || !mixer->IsPlugin(software_mixer_plugin))
 		return -1;
 
@@ -125,7 +125,7 @@ MultipleOutputs::GetSoftwareVolume() const
 	unsigned ok = 0;
 	int total = 0;
 
-	for (auto ao : outputs) {
+	for (auto *ao : outputs) {
 		int volume = output_mixer_get_software_volume(*ao);
 		if (volume >= 0) {
 			total += volume;
@@ -144,8 +144,8 @@ MultipleOutputs::SetSoftwareVolume(unsigned volume)
 {
 	assert(volume <= PCM_VOLUME_1);
 
-	for (auto ao : outputs) {
-		const auto mixer = ao->mixer;
+	for (auto *ao : outputs) {
+		auto *mixer = ao->GetMixer();
 
 		if (mixer != nullptr &&
 		    (&mixer->plugin == &software_mixer_plugin ||
diff --git a/src/output/Control.cxx b/src/output/Control.cxx
index 55076a5d4..4ae8f5e08 100644
--- a/src/output/Control.cxx
+++ b/src/output/Control.cxx
@@ -18,6 +18,7 @@
  */
 
 #include "config.h"
+#include "Control.hxx"
 #include "Internal.hxx"
 #include "OutputPlugin.hxx"
 #include "Domain.hxx"
@@ -36,6 +37,72 @@ static constexpr PeriodClock::Duration REOPEN_AFTER = std::chrono::seconds(10);
 
 struct notify audio_output_client_notify;
 
+AudioOutputControl::AudioOutputControl(AudioOutput *_output)
+	:output(_output), mutex(output->mutex)
+{
+}
+
+const char *
+AudioOutputControl::GetName() const
+{
+	return output->GetName();
+}
+
+AudioOutputClient &
+AudioOutputControl::GetClient()
+{
+	return *output->client;
+}
+
+Mixer *
+AudioOutputControl::GetMixer() const
+{
+	return output->mixer;
+}
+
+bool
+AudioOutputControl::IsEnabled() const
+{
+	return output->IsEnabled();
+}
+
+bool
+AudioOutputControl::LockSetEnabled(bool new_value)
+{
+	const std::lock_guard<Mutex> protect(mutex);
+
+	if (new_value == output->enabled)
+		return false;
+
+	output->enabled = new_value;
+	return true;
+}
+
+bool
+AudioOutputControl::LockToggleEnabled()
+{
+	const std::lock_guard<Mutex> protect(mutex);
+	return output->enabled = !output->enabled;
+}
+
+bool
+AudioOutputControl::IsOpen() const
+{
+	return output->IsOpen();
+}
+
+bool
+AudioOutputControl::IsBusy() const
+{
+	return output->IsBusy();
+}
+
+const std::exception_ptr &
+AudioOutputControl::GetLastError() const
+{
+	return output->GetLastError();
+}
+
 void
 AudioOutput::WaitForCommand()
 {
@@ -47,6 +114,12 @@ AudioOutput::WaitForCommand()
 }
 
 void
+AudioOutputControl::WaitForCommand()
+{
+	output->WaitForCommand();
+}
+
+void
 AudioOutput::CommandAsync(Command cmd)
 {
 	assert(IsCommandFinished());
@@ -104,6 +177,18 @@ AudioOutput::DisableAsync()
 	CommandAsync(Command::DISABLE);
 }
 
+void
+AudioOutputControl::EnableDisableAsync()
+{
+	output->EnableDisableAsync();
+}
+
+void
+AudioOutputControl::LockPauseAsync()
+{
+	output->LockPauseAsync();
+}
+
 inline bool
 AudioOutput::Open(const AudioFormat audio_format, const MusicPipe &mp)
 {
@@ -176,6 +261,38 @@ AudioOutput::LockUpdate(const AudioFormat audio_format,
 }
 
 void
+AudioOutputControl::LockRelease()
+{
+	output->LockRelease();
+}
+
+void
+AudioOutputControl::LockCloseWait()
+{
+	output->LockCloseWait();
+}
+
+bool
+AudioOutputControl::LockUpdate(const AudioFormat audio_format,
+			       const MusicPipe &mp,
+			       bool force)
+{
+	return output->LockUpdate(audio_format, mp, force);
+}
+
+bool
+AudioOutputControl::LockIsChunkConsumed(const MusicChunk &chunk) const
+{
+	return output->LockIsChunkConsumed(chunk);
+}
+
+void
+AudioOutputControl::ClearTailChunk(const MusicChunk &chunk)
+{
+	output->ClearTailChunk(chunk);
+}
+
+void
 AudioOutput::LockPlay()
 {
 	const std::lock_guard<Mutex> protect(mutex);
@@ -254,6 +371,12 @@ AudioOutput::LockCloseWait()
 }
 
 void
+AudioOutputControl::SetReplayGainMode(ReplayGainMode _mode)
+{
+	return output->SetReplayGainMode(_mode);
+}
+
+void
 AudioOutput::StopThread()
 {
 	assert(thread.IsDefined());
@@ -276,6 +399,12 @@ AudioOutput::BeginDestroy()
 }
 
 void
+AudioOutputControl::BeginDestroy()
+{
+	output->BeginDestroy();
+}
+
+void
 AudioOutput::FinishDestroy()
 {
 	if (thread.IsDefined())
@@ -283,3 +412,34 @@ AudioOutput::FinishDestroy()
 
 	audio_output_free(this);
 }
+
+void
+AudioOutputControl::FinishDestroy()
+{
+	output->FinishDestroy();
+	output = nullptr;
+}
+
+void
+AudioOutputControl::LockPlay()
+{
+	output->LockPlay();
+}
+
+void
+AudioOutputControl::LockDrainAsync()
+{
+	output->LockDrainAsync();
+}
+
+void
+AudioOutputControl::LockCancelAsync()
+{
+	output->LockCancelAsync();
+}
+
+void
+AudioOutputControl::LockAllowPlay()
+{
+	output->LockAllowPlay();
+}
diff --git a/src/output/Control.hxx b/src/output/Control.hxx
index 778b6245e..8aa2161a1 100644
--- a/src/output/Control.hxx
+++ b/src/output/Control.hxx
@@ -20,6 +20,112 @@
 #ifndef MPD_OUTPUT_CONTROL_HXX
 #define MPD_OUTPUT_CONTROL_HXX
 
+#include "Compiler.h"
+
+#include <utility>
+#include <exception>
+
+#ifndef NDEBUG
+#include <assert.h>
+#endif
+
+#include <stdint.h>
+
+enum class ReplayGainMode : uint8_t;
+struct AudioFormat;
 struct AudioOutput;
+struct MusicChunk;
+class MusicPipe;
+class Mutex;
+class Mixer;
+class AudioOutputClient;
+
+/**
+ * Controller for an #AudioOutput and its output thread.
+ */
+class AudioOutputControl {
+	AudioOutput *output;
+
+public:
+	Mutex &mutex;
+
+	explicit AudioOutputControl(AudioOutput *_output);
+
+#ifndef NDEBUG
+	~AudioOutputControl() {
+		assert(output == nullptr);
+	}
+#endif
+
+	AudioOutputControl(const AudioOutputControl &) = delete;
+	AudioOutputControl &operator=(const AudioOutputControl &) = delete;
+
+	gcc_pure
+	const char *GetName() const;
+
+	AudioOutputClient &GetClient();
+
+	gcc_pure
+	Mixer *GetMixer() const;
+
+	gcc_pure
+	bool IsEnabled() const;
+
+	/**
+	 * @return true if the value has been modified
+	 */
+	bool LockSetEnabled(bool new_value);
+
+	/**
+	 * @return the new "enabled" value
+	 */
+	bool LockToggleEnabled();
+
+	gcc_pure
+	bool IsOpen() const;
+
+	gcc_pure
+	bool IsBusy() const;
+
+	/**
+	 * Caller must lock the mutex.
+	 */
+	gcc_const
+	const std::exception_ptr &GetLastError() const;
+
+	void WaitForCommand();
+
+	void BeginDestroy();
+	void FinishDestroy();
+
+	void EnableDisableAsync();
+	void LockPauseAsync();
+
+	void LockCloseWait();
+	void LockRelease();
+
+	void SetReplayGainMode(ReplayGainMode _mode);
+
+	/**
+	 * Opens or closes the device, depending on the "enabled"
+	 * flag.
+	 *
+	 * @param force true to ignore the #fail_timer
+	 * @return true if the device is open
+	 */
+	bool LockUpdate(const AudioFormat audio_format,
+			const MusicPipe &mp,
+			bool force);
+
+	gcc_pure
+	bool LockIsChunkConsumed(const MusicChunk &chunk) const;
+
+	void ClearTailChunk(const MusicChunk &chunk);
+
+	void LockPlay();
+	void LockDrainAsync();
+	void LockCancelAsync();
+	void LockAllowPlay();
+};
 
 #endif
diff --git a/src/output/MultipleOutputs.cxx b/src/output/MultipleOutputs.cxx
index c3d584652..3781d96dc 100644
--- a/src/output/MultipleOutputs.cxx
+++ b/src/output/MultipleOutputs.cxx
@@ -43,9 +43,9 @@ MultipleOutputs::MultipleOutputs(MixerListener &_mixer_listener)
 MultipleOutputs::~MultipleOutputs()
 {
 	/* parallel destruction */
-	for (auto i : outputs)
+	for (auto *i : outputs)
 		i->BeginDestroy();
-	for (auto i : outputs)
+	for (auto *i : outputs)
 		i->FinishDestroy();
 }
 
@@ -80,7 +80,7 @@ MultipleOutputs::Configure(EventLoop &event_loop,
 			throw FormatRuntimeError("output devices with identical "
 						 "names: %s", output->GetName());
 
-		outputs.push_back(output);
+		outputs.push_back(new AudioOutputControl(output));
 	}
 
 	if (outputs.empty()) {
@@ -89,7 +89,7 @@ MultipleOutputs::Configure(EventLoop &event_loop,
 		auto output = LoadOutput(event_loop, replay_gain_config,
 					 mixer_listener,
 					 client, empty);
-		outputs.push_back(output);
+		outputs.push_back(new AudioOutputControl(output));
 	}
 }
 
@@ -104,13 +104,13 @@ MultipleOutputs::AddNullOutput(EventLoop &event_loop,
 	auto output = LoadOutput(event_loop, replay_gain_config,
 				 mixer_listener,
 				 client, block);
-	outputs.push_back(output);
+	outputs.push_back(new AudioOutputControl(output));
 }
 
-AudioOutput *
-MultipleOutputs::FindByName(const char *name) const
+AudioOutputControl *
+MultipleOutputs::FindByName(const char *name)
 {
-	for (auto i : outputs)
+	for (auto *i : outputs)
 		if (strcmp(i->GetName(), name) == 0)
 			return i;
 
@@ -122,12 +122,12 @@ MultipleOutputs::EnableDisable()
 {
 	/* parallel execution */
 
-	for (auto ao : outputs) {
+	for (auto *ao : outputs) {
 		const std::lock_guard<Mutex> lock(ao->mutex);
 		ao->EnableDisableAsync();
 	}
 
-	for (auto ao : outputs) {
+	for (auto *ao : outputs) {
 		const std::lock_guard<Mutex> lock(ao->mutex);
 		ao->WaitForCommand();
 	}
@@ -136,7 +136,7 @@ MultipleOutputs::EnableDisable()
 bool
 MultipleOutputs::AllFinished() const
 {
-	for (auto ao : outputs) {
+	for (auto *ao : outputs) {
 		const std::lock_guard<Mutex> protect(ao->mutex);
 		if (ao->IsBusy())
 			return false;
@@ -155,7 +155,7 @@ MultipleOutputs::WaitAll()
 void
 MultipleOutputs::AllowPlay()
 {
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockAllowPlay();
 }
 
@@ -167,7 +167,7 @@ MultipleOutputs::Update(bool force)
 	if (!input_audio_format.IsDefined())
 		return false;
 
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ret = ao->LockUpdate(input_audio_format, *pipe, force)
 			|| ret;
 
@@ -177,7 +177,7 @@ MultipleOutputs::Update(bool force)
 void
 MultipleOutputs::SetReplayGainMode(ReplayGainMode mode)
 {
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->SetReplayGainMode(mode);
 }
 
@@ -195,7 +195,7 @@ MultipleOutputs::Play(MusicChunk *chunk)
 
 	pipe->Push(chunk);
 
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockPlay();
 }
 
@@ -228,7 +228,7 @@ MultipleOutputs::Open(const AudioFormat audio_format,
 
 	std::exception_ptr first_error;
 
-	for (auto ao : outputs) {
+	for (auto *ao : outputs) {
 		const std::lock_guard<Mutex> lock(ao->mutex);
 
 		if (ao->IsEnabled())
@@ -259,7 +259,7 @@ MultipleOutputs::Open(const AudioFormat audio_format,
 bool
 MultipleOutputs::IsChunkConsumed(const MusicChunk *chunk) const
 {
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		if (!ao->LockIsChunkConsumed(*chunk))
 			return false;
 
@@ -274,7 +274,7 @@ MultipleOutputs::ClearTailChunk(const MusicChunk *chunk,
 	assert(pipe->Contains(chunk));
 
 	for (unsigned i = 0, n = outputs.size(); i != n; ++i) {
-		AudioOutput *ao = outputs[i];
+		auto *ao = outputs[i];
 
 		/* this mutex will be unlocked by the caller when it's
 		   ready */
@@ -343,7 +343,7 @@ MultipleOutputs::Pause()
 {
 	Update(false);
 
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockPauseAsync();
 
 	WaitAll();
@@ -352,7 +352,7 @@ MultipleOutputs::Pause()
 void
 MultipleOutputs::Drain()
 {
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockDrainAsync();
 
 	WaitAll();
@@ -363,7 +363,7 @@ MultipleOutputs::Cancel()
 {
 	/* send the cancel() command to all audio outputs */
 
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockCancelAsync();
 
 	WaitAll();
@@ -386,7 +386,7 @@ MultipleOutputs::Cancel()
 void
 MultipleOutputs::Close()
 {
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockCloseWait();
 
 	if (pipe != nullptr) {
@@ -407,7 +407,7 @@ MultipleOutputs::Close()
 void
 MultipleOutputs::Release()
 {
-	for (auto ao : outputs)
+	for (auto *ao : outputs)
 		ao->LockRelease();
 
 	if (pipe != nullptr) {
diff --git a/src/output/MultipleOutputs.hxx b/src/output/MultipleOutputs.hxx
index b9e12c07e..ccadaccbd 100644
--- a/src/output/MultipleOutputs.hxx
+++ b/src/output/MultipleOutputs.hxx
@@ -26,6 +26,7 @@
 #ifndef OUTPUT_ALL_H
 #define OUTPUT_ALL_H
 
+#include "Control.hxx"
 #include "AudioFormat.hxx"
 #include "ReplayGainMode.hxx"
 #include "Chrono.hxx"
@@ -47,7 +48,7 @@ struct ReplayGainConfig;
 class MultipleOutputs {
 	MixerListener &mixer_listener;
 
-	std::vector<AudioOutput *> outputs;
+	std::vector<AudioOutputControl *> outputs;
 
 	AudioFormat input_audio_format = AudioFormat::Undefined();
 
@@ -96,13 +97,13 @@ public:
 	/**
 	 * Returns the "i"th audio output device.
 	 */
-	const AudioOutput &Get(unsigned i) const {
+	const AudioOutputControl &Get(unsigned i) const {
 		assert(i < Size());
 
 		return *outputs[i];
 	}
 
-	AudioOutput &Get(unsigned i) {
+	AudioOutputControl &Get(unsigned i) {
 		assert(i < Size());
 
 		return *outputs[i];
@@ -113,7 +114,7 @@ public:
 	 * Returns nullptr if the name does not exist.
 	 */
 	gcc_pure
-	AudioOutput *FindByName(const char *name) const;
+	AudioOutputControl *FindByName(const char *name);
 
 	/**
 	 * Checks the "enabled" flag of all audio outputs, and if one has
diff --git a/src/output/OutputCommand.cxx b/src/output/OutputCommand.cxx
index 510211a0c..1da8e5fdf 100644
--- a/src/output/OutputCommand.cxx
+++ b/src/output/OutputCommand.cxx
@@ -42,19 +42,18 @@ audio_output_enable_index(MultipleOutputs &outputs, unsigned idx)
 	if (idx >= outputs.Size())
 		return false;
 
-	AudioOutput &ao = outputs.Get(idx);
-	if (ao.enabled)
+	auto &ao = outputs.Get(idx);
+	if (!ao.LockSetEnabled(true))
 		return true;
 
-	ao.enabled = true;
 	idle_add(IDLE_OUTPUT);
 
-	if (ao.mixer != nullptr) {
+	if (ao.GetMixer() != nullptr) {
 		InvalidateHardwareVolume();
 		idle_add(IDLE_MIXER);
 	}
 
-	ao.client->ApplyEnabled();
+	ao.GetClient().ApplyEnabled();
 
 	++audio_output_state_version;
 
@@ -67,21 +66,20 @@ audio_output_disable_index(MultipleOutputs &outputs, unsigned idx)
 	if (idx >= outputs.Size())
 		return false;
 
-	AudioOutput &ao = outputs.Get(idx);
-	if (!ao.enabled)
+	auto &ao = outputs.Get(idx);
+	if (!ao.LockSetEnabled(false))
 		return true;
 
-	ao.enabled = false;
 	idle_add(IDLE_OUTPUT);
 
-	Mixer *mixer = ao.mixer;
+	auto *mixer = ao.GetMixer();
 	if (mixer != nullptr) {
 		mixer_close(mixer);
 		InvalidateHardwareVolume();
 		idle_add(IDLE_MIXER);
 	}
 
-	ao.client->ApplyEnabled();
+	ao.GetClient().ApplyEnabled();
 
 	++audio_output_state_version;
 
@@ -94,12 +92,12 @@ audio_output_toggle_index(MultipleOutputs &outputs, unsigned idx)
 	if (idx >= outputs.Size())
 		return false;
 
-	AudioOutput &ao = outputs.Get(idx);
-	const bool enabled = ao.enabled = !ao.enabled;
+	auto &ao = outputs.Get(idx);
+	const bool enabled = ao.LockToggleEnabled();
 	idle_add(IDLE_OUTPUT);
 
 	if (!enabled) {
-		Mixer *mixer = ao.mixer;
+		auto *mixer = ao.GetMixer();
 		if (mixer != nullptr) {
 			mixer_close(mixer);
 			InvalidateHardwareVolume();
@@ -107,7 +105,7 @@ audio_output_toggle_index(MultipleOutputs &outputs, unsigned idx)
 		}
 	}
 
-	ao.client->ApplyEnabled();
+	ao.GetClient().ApplyEnabled();
 
 	++audio_output_state_version;
 
diff --git a/src/output/Print.cxx b/src/output/Print.cxx
index f24d09eda..01aa6a37a 100644
--- a/src/output/Print.cxx
+++ b/src/output/Print.cxx
@@ -32,7 +32,7 @@ void
 printAudioDevices(Response &r, const MultipleOutputs &outputs)
 {
 	for (unsigned i = 0, n = outputs.Size(); i != n; ++i) {
-		const AudioOutput &ao = outputs.Get(i);
+		const auto &ao = outputs.Get(i);
 
 		r.Format("outputid: %i\n"
 			 "outputname: %s\n"
diff --git a/src/output/State.cxx b/src/output/State.cxx
index b57f8ce4d..dd84901d7 100644
--- a/src/output/State.cxx
+++ b/src/output/State.cxx
@@ -42,7 +42,7 @@ audio_output_state_save(BufferedOutputStream &os,
 			const MultipleOutputs &outputs)
 {
 	for (unsigned i = 0, n = outputs.Size(); i != n; ++i) {
-		const AudioOutput &ao = outputs.Get(i);
+		const auto &ao = outputs.Get(i);
 		const std::lock_guard<Mutex> lock(ao.mutex);
 
 		os.Format(AUDIO_DEVICE_STATE "%d:%s\n",
@@ -70,14 +70,14 @@ audio_output_state_read(const char *line, MultipleOutputs &outputs)
 		return true;
 
 	name = endptr + 1;
-	AudioOutput *ao = outputs.FindByName(name);
+	auto *ao = outputs.FindByName(name);
 	if (ao == NULL) {
 		FormatDebug(output_domain,
 			    "Ignoring device state for '%s'", name);
 		return true;
 	}
 
-	ao->enabled = false;
+	ao->LockSetEnabled(false);
 	return true;
 }
 
diff --git a/src/output/Thread.cxx b/src/output/Thread.cxx
index 7b8aa435e..785ea947a 100644
--- a/src/output/Thread.cxx
+++ b/src/output/Thread.cxx
@@ -18,6 +18,7 @@
  */
 
 #include "config.h"
+#include "Control.hxx"
 #include "Internal.hxx"
 #include "Client.hxx"
 #include "OutputAPI.hxx"