*: add "noexcept" to many, many function prototypes

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

src/output/Init.cxx

@@ -89,7 +89,7 @@ audio_output_detect()
  */
 gcc_pure
 static MixerType
-audio_output_mixer_type(const ConfigBlock &block)
+audio_output_mixer_type(const ConfigBlock &block) noexcept
 {
 	/* read the local "mixer_type" setting */
 	const char *p = block.GetBlockValue("mixer_type");

src/output/Internal.cxx

@@ -21,7 +21,7 @@
 #include "Internal.hxx"
 
 bool
-AudioOutput::IsChunkConsumed(const MusicChunk &chunk) const
+AudioOutput::IsChunkConsumed(const MusicChunk &chunk) const noexcept
 {
 	if (!open)
 		return true;

src/output/Internal.hxx

@@ -436,10 +436,10 @@ public:
 	 * Caller must lock the mutex.
 	 */
 	gcc_pure
-	bool IsChunkConsumed(const MusicChunk &chunk) const;
+	bool IsChunkConsumed(const MusicChunk &chunk) const noexcept;
 
 	gcc_pure
-	bool LockIsChunkConsumed(const MusicChunk &chunk) {
+	bool LockIsChunkConsumed(const MusicChunk &chunk) noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		return IsChunkConsumed(chunk);
 	}

src/output/MultipleOutputs.cxx

@@ -94,7 +94,7 @@ MultipleOutputs::Configure(EventLoop &event_loop,
 }
 
 AudioOutput *
-MultipleOutputs::FindByName(const char *name) const
+MultipleOutputs::FindByName(const char *name) const noexcept
 {
 	for (auto i : outputs)
 		if (strcmp(i->GetName(), name) == 0)
@@ -120,7 +120,7 @@ MultipleOutputs::EnableDisable()
 }
 
 bool
-MultipleOutputs::AllFinished() const
+MultipleOutputs::AllFinished() const noexcept
 {
 	for (auto ao : outputs) {
 		const std::lock_guard<Mutex> protect(ao->mutex);
@@ -132,7 +132,7 @@ MultipleOutputs::AllFinished() const
 }
 
 void
-MultipleOutputs::WaitAll()
+MultipleOutputs::WaitAll() noexcept
 {
 	while (!AllFinished())
 		audio_output_client_notify.Wait();
@@ -243,7 +243,7 @@ MultipleOutputs::Open(const AudioFormat audio_format,
 }
 
 bool
-MultipleOutputs::IsChunkConsumed(const MusicChunk *chunk) const
+MultipleOutputs::IsChunkConsumed(const MusicChunk *chunk) const noexcept
 {
 	for (auto ao : outputs)
 		if (!ao->LockIsChunkConsumed(*chunk))

src/output/MultipleOutputs.hxx

@@ -109,7 +109,7 @@ public:
 	 * Returns nullptr if the name does not exist.
 	 */
 	gcc_pure
-	AudioOutput *FindByName(const char *name) const;
+	AudioOutput *FindByName(const char *name) const noexcept;
 
 	/**
 	 * Checks the "enabled" flag of all audio outputs, and if one has
@@ -195,7 +195,7 @@ public:
 	 * 0..100).  Returns -1 if no mixer can be queried.
 	 */
 	gcc_pure
-	int GetVolume() const;
+	int GetVolume() const noexcept;
 
 	/**
 	 * Sets the volume on all available mixers.
@@ -203,7 +203,7 @@ public:
 	 * @param volume the volume (range 0..100)
 	 * @return true on success, false on failure
 	 */
-	bool SetVolume(unsigned volume);
+	bool SetVolume(unsigned volume) noexcept;
 
 	/**
 	 * Similar to GetVolume(), but gets the volume only for
@@ -211,7 +211,7 @@ public:
 	 * function fails if no software mixer is configured.
 	 */
 	gcc_pure
-	int GetSoftwareVolume() const;
+	int GetSoftwareVolume() const noexcept;
 
 	/**
 	 * Similar to SetVolume(), but sets the volume only for
@@ -219,7 +219,7 @@ public:
 	 * function cannot fail, because the underlying software
 	 * mixers cannot fail either.
 	 */
-	void SetSoftwareVolume(unsigned volume);
+	void SetSoftwareVolume(unsigned volume) noexcept;
 
 private:
 	/**
@@ -227,9 +227,9 @@ private:
 	 * command.
 	 */
 	gcc_pure
-	bool AllFinished() const;
+	bool AllFinished() const noexcept;
 
-	void WaitAll();
+	void WaitAll() noexcept;
 
 	/**
 	 * Signals all audio outputs which are open.
@@ -247,7 +247,7 @@ private:
 	/**
 	 * Has this chunk been consumed by all audio outputs?
 	 */
-	bool IsChunkConsumed(const MusicChunk *chunk) const;
+	bool IsChunkConsumed(const MusicChunk *chunk) const noexcept;
 
 	/**
 	 * There's only one chunk left in the pipe (#pipe), and all

src/output/OutputPlugin.cxx

@@ -64,7 +64,7 @@ ao_plugin_close(AudioOutput *ao)
 }
 
 std::chrono::steady_clock::duration
-ao_plugin_delay(AudioOutput *ao)
+ao_plugin_delay(AudioOutput *ao) noexcept
 {
 	return ao->plugin.delay != nullptr
 		? ao->plugin.delay(ao)

src/output/OutputPlugin.hxx

@@ -101,7 +101,7 @@ struct AudioOutputPlugin {
 	 *
 	 * @return the duration to wait
 	 */
-	std::chrono::steady_clock::duration (*delay)(AudioOutput *data);
+	std::chrono::steady_clock::duration (*delay)(AudioOutput *data) noexcept;
 
 	/**
 	 * Display metadata for the next chunk.  Optional method,
@@ -182,7 +182,7 @@ ao_plugin_close(AudioOutput *ao);
 
 gcc_pure
 std::chrono::steady_clock::duration
-ao_plugin_delay(AudioOutput *ao);
+ao_plugin_delay(AudioOutput *ao) noexcept;
 
 void
 ao_plugin_send_tag(AudioOutput *ao, const Tag &tag);

src/output/SharedPipeConsumer.cxx

@@ -23,7 +23,7 @@
 #include "MusicPipe.hxx"
 
 const MusicChunk *
-SharedPipeConsumer::Get()
+SharedPipeConsumer::Get() noexcept
 {
 	if (chunk != nullptr) {
 		if (!consumed)
@@ -42,7 +42,7 @@ SharedPipeConsumer::Get()
 }
 
 bool
-SharedPipeConsumer::IsConsumed(const MusicChunk &_chunk) const
+SharedPipeConsumer::IsConsumed(const MusicChunk &_chunk) const noexcept
 {
 	if (chunk == nullptr)
 		return false;

src/output/SharedPipeConsumer.hxx

@@ -75,7 +75,7 @@ public:
 		chunk = nullptr;
 	}
 
-	const MusicChunk *Get();
+	const MusicChunk *Get() noexcept;
 
 	void Consume(gcc_unused const MusicChunk &_chunk) {
 		assert(chunk != nullptr);
@@ -85,9 +85,9 @@ public:
 	}
 
 	gcc_pure
-	bool IsConsumed(const MusicChunk &_chunk) const;
+	bool IsConsumed(const MusicChunk &_chunk) const noexcept;
 
-	void ClearTail(gcc_unused const MusicChunk &_chunk) {
+	void ClearTail(gcc_unused const MusicChunk &_chunk) noexcept {
 		assert(chunk == &_chunk);
 		assert(consumed);
 		chunk = nullptr;

src/output/Source.cxx

@@ -60,7 +60,7 @@ AudioOutputSource::Open(AudioFormat audio_format, const MusicPipe &_pipe,
 }
 
 void
-AudioOutputSource::Close()
+AudioOutputSource::Close() noexcept
 {
 	assert(in_audio_format.IsValid());
 	in_audio_format.Clear();
@@ -71,7 +71,7 @@ AudioOutputSource::Close()
 }
 
 void
-AudioOutputSource::Cancel()
+AudioOutputSource::Cancel() noexcept
 {
 	current_chunk = nullptr;
 	pipe.Cancel();
@@ -114,7 +114,7 @@ try {
 }
 
 void
-AudioOutputSource::CloseFilter()
+AudioOutputSource::CloseFilter() noexcept
 {
 	delete replay_gain_filter_instance;
 	replay_gain_filter_instance = nullptr;

src/output/Source.hxx

@@ -138,8 +138,8 @@ public:
 			 PreparedFilter *prepared_other_replay_gain_filter,
 			 PreparedFilter *prepared_filter);
 
-	void Close();
-	void Cancel();
+	void Close() noexcept;
+	void Cancel() noexcept;
 
 	/**
 	 * Ensure that ReadTag() or PeekData() return any input.
@@ -181,13 +181,13 @@ public:
 	 */
 	void ConsumeData(size_t nbytes) noexcept;
 
-	bool IsChunkConsumed(const MusicChunk &chunk) const {
+	bool IsChunkConsumed(const MusicChunk &chunk) const  noexcept {
 		assert(IsOpen());
 
 		return pipe.IsConsumed(chunk);
 	}
 
-	void ClearTailChunk(const MusicChunk &chunk) {
+	void ClearTailChunk(const MusicChunk &chunk) noexcept {
 		pipe.ClearTail(chunk);
 	}
 
@@ -197,7 +197,7 @@ private:
 			PreparedFilter *prepared_other_replay_gain_filter,
 			PreparedFilter *prepared_filter);
 
-	void CloseFilter();
+	void CloseFilter() noexcept;
 
 	ConstBuffer<void> GetChunkData(const MusicChunk &chunk,
 				       Filter *replay_gain_filter,

src/output/Wrapper.hxx

@@ -63,7 +63,7 @@ struct AudioOutputWrapper {
 	}
 
 	gcc_pure
-	static std::chrono::steady_clock::duration Delay(AudioOutput *ao) {
+	static std::chrono::steady_clock::duration Delay(AudioOutput *ao) noexcept {
 		T &t = Cast(*ao);
 		return t.Delay();
 	}

src/output/plugins/AlsaOutputPlugin.cxx

@@ -249,7 +249,7 @@ alsa_test_default_device()
  */
 gcc_const
 static snd_pcm_format_t
-ToAlsaPcmFormat(SampleFormat sample_format)
+ToAlsaPcmFormat(SampleFormat sample_format) noexcept
 {
 	switch (sample_format) {
 	case SampleFormat::UNDEFINED:
@@ -287,7 +287,7 @@ ToAlsaPcmFormat(SampleFormat sample_format)
  * SND_PCM_FORMAT_UNKNOWN if the format cannot be byte-swapped.
  */
 static snd_pcm_format_t
-ByteSwapAlsaPcmFormat(snd_pcm_format_t fmt)
+ByteSwapAlsaPcmFormat(snd_pcm_format_t fmt) noexcept
 {
 	switch (fmt) {
 	case SND_PCM_FORMAT_S16_LE: return SND_PCM_FORMAT_S16_BE;

src/output/plugins/FifoOutputPlugin.cxx

@@ -66,7 +66,7 @@ public:
 	void Open(AudioFormat &audio_format);
 	void Close();
 
-	std::chrono::steady_clock::duration Delay() const;
+	std::chrono::steady_clock::duration Delay() const noexcept;
 	size_t Play(const void *chunk, size_t size);
 	void Cancel();
 };
@@ -205,7 +205,7 @@ FifoOutput::Cancel()
 }
 
 inline std::chrono::steady_clock::duration
-FifoOutput::Delay() const
+FifoOutput::Delay() const noexcept
 {
 	return timer->IsStarted()
 		? timer->GetDelay()

src/output/plugins/JackOutputPlugin.cxx

@@ -119,7 +119,7 @@ struct JackOutput {
 	 * on all channels.
 	 */
 	gcc_pure
-	jack_nframes_t GetAvailable() const;
+	jack_nframes_t GetAvailable() const noexcept;
 
 	void Process(jack_nframes_t nframes);
 
@@ -128,7 +128,7 @@ struct JackOutput {
 	 */
 	size_t WriteSamples(const float *src, size_t n_frames);
 
-	std::chrono::steady_clock::duration Delay() const {
+	std::chrono::steady_clock::duration Delay() const noexcept {
 		return base.pause && pause && !shutdown
 			? std::chrono::seconds(1)
 			: std::chrono::steady_clock::duration::zero();
@@ -215,7 +215,7 @@ JackOutput::JackOutput(const ConfigBlock &block)
 }
 
 inline jack_nframes_t
-JackOutput::GetAvailable() const
+JackOutput::GetAvailable() const noexcept
 {
 	size_t min = jack_ringbuffer_read_space(ringbuffer[0]);
 

src/output/plugins/NullOutputPlugin.cxx

@@ -49,7 +49,7 @@ public:
 			delete timer;
 	}
 
-	std::chrono::steady_clock::duration Delay() const {
+	std::chrono::steady_clock::duration Delay() const noexcept {
 		return sync && timer->IsStarted()
 			? timer->GetDelay()
 			: std::chrono::steady_clock::duration::zero();

src/output/plugins/OpenALOutputPlugin.cxx

@@ -58,7 +58,7 @@ class OpenALOutput {
 	void Close();
 
 	gcc_pure
-	std::chrono::steady_clock::duration Delay() const {
+	std::chrono::steady_clock::duration Delay() const noexcept {
 		return filled < NUM_BUFFERS || HasProcessed()
 			? std::chrono::steady_clock::duration::zero()
 			/* we don't know exactly how long we must wait

src/output/plugins/OssOutputPlugin.cxx

@@ -391,7 +391,7 @@ oss_setup_sample_rate(int fd, AudioFormat &audio_format)
  */
 gcc_const
 static int
-sample_format_to_oss(SampleFormat format)
+sample_format_to_oss(SampleFormat format) noexcept
 {
 	switch (format) {
 	case SampleFormat::UNDEFINED:
@@ -430,7 +430,7 @@ sample_format_to_oss(SampleFormat format)
  */
 gcc_const
 static SampleFormat
-sample_format_from_oss(int format)
+sample_format_from_oss(int format) noexcept
 {
 	switch (format) {
 	case AFMT_S8:

src/output/plugins/PulseOutputPlugin.cxx

@@ -90,7 +90,6 @@ public:
 		Signal();
 	}
 
-	gcc_const
 	static bool TestDefaultDevice();
 
 	static PulseOutput *Create(const ConfigBlock &block);

src/output/plugins/RoarOutputPlugin.cxx

@@ -73,7 +73,7 @@ static constexpr Domain roar_output_domain("roar_output");
 
 gcc_pure
 static int
-GetConfiguredRole(const ConfigBlock &block)
+GetConfiguredRole(const ConfigBlock &block) noexcept
 {
 	const char *role = block.GetBlockValue("role");
 	return role != nullptr

src/output/plugins/ShoutOutputPlugin.cxx

@@ -63,7 +63,7 @@ struct ShoutOutput final {
 	void Open(AudioFormat &audio_format);
 	void Close();
 
-	std::chrono::steady_clock::duration Delay() const;
+	std::chrono::steady_clock::duration Delay() const noexcept;
 	void SendTag(const Tag &tag);
 	size_t Play(const void *chunk, size_t size);
 	void Cancel();
@@ -361,7 +361,7 @@ ShoutOutput::Open(AudioFormat &audio_format)
 }
 
 std::chrono::steady_clock::duration
-ShoutOutput::Delay() const
+ShoutOutput::Delay() const noexcept
 {
 	int delay = shout_delay(shout_conn);
 	if (delay < 0)

src/output/plugins/httpd/HttpdClient.cxx

@@ -260,7 +260,7 @@ HttpdClient::TryWritePageN(const Page &page, size_t position, ssize_t n)
 }
 
 ssize_t
-HttpdClient::GetBytesTillMetaData() const
+HttpdClient::GetBytesTillMetaData() const noexcept
 {
 	if (metadata_requested &&
 	    current_page->size - current_position > metaint - metadata_fill)

src/output/plugins/httpd/HttpdClient.hxx

@@ -168,7 +168,7 @@ public:
 	bool SendResponse();
 
 	gcc_pure
-	ssize_t GetBytesTillMetaData() const;
+	ssize_t GetBytesTillMetaData() const noexcept;
 
 	ssize_t TryWritePage(const Page &page, size_t position);
 	ssize_t TryWritePageN(const Page &page, size_t position, ssize_t n);

src/output/plugins/httpd/HttpdInternal.hxx

@@ -218,7 +218,7 @@ public:
 	void SendHeader(HttpdClient &client) const;
 
 	gcc_pure
-	std::chrono::steady_clock::duration Delay() const;
+	std::chrono::steady_clock::duration Delay() const noexcept;
 
 	/**
 	 * Reads data from the encoder (as much as available) and

src/output/plugins/httpd/HttpdOutputPlugin.cxx

@@ -345,7 +345,7 @@ HttpdOutput::SendHeader(HttpdClient &client) const
 }
 
 inline std::chrono::steady_clock::duration
-HttpdOutput::Delay() const
+HttpdOutput::Delay() const noexcept
 {
 	if (!LockHasClients() && base.pause) {
 		/* if there's no client and this output is paused,
@@ -366,7 +366,7 @@ HttpdOutput::Delay() const
 }
 
 static std::chrono::steady_clock::duration
-httpd_output_delay(AudioOutput *ao)
+httpd_output_delay(AudioOutput *ao) noexcept
 {
 	HttpdOutput *httpd = HttpdOutput::Cast(ao);