output/*: move to output/plugins/

src/output/plugins/PulseOutputPlugin.cxx

@@ -0,0 +1,889 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "PulseOutputPlugin.hxx"
+#include "../OutputAPI.hxx"
+#include "MixerList.hxx"
+#include "mixer/PulseMixerPlugin.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+#include "Log.hxx"
+
+#include <glib.h>
+
+#include <pulse/thread-mainloop.h>
+#include <pulse/context.h>
+#include <pulse/stream.h>
+#include <pulse/introspect.h>
+#include <pulse/subscribe.h>
+#include <pulse/error.h>
+#include <pulse/version.h>
+
+#include <assert.h>
+#include <stddef.h>
+
+#define MPD_PULSE_NAME "Music Player Daemon"
+
+struct PulseOutput {
+	struct audio_output base;
+
+	const char *name;
+	const char *server;
+	const char *sink;
+
+	PulseMixer *mixer;
+
+	struct pa_threaded_mainloop *mainloop;
+	struct pa_context *context;
+	struct pa_stream *stream;
+
+	size_t writable;
+};
+
+static constexpr Domain pulse_output_domain("pulse_output");
+
+static void
+SetError(Error &error, pa_context *context, const char *msg)
+{
+	const int e = pa_context_errno(context);
+	error.Format(pulse_output_domain, e, "%s: %s", msg, pa_strerror(e));
+}
+
+void
+pulse_output_lock(PulseOutput *po)
+{
+	pa_threaded_mainloop_lock(po->mainloop);
+}
+
+void
+pulse_output_unlock(PulseOutput *po)
+{
+	pa_threaded_mainloop_unlock(po->mainloop);
+}
+
+void
+pulse_output_set_mixer(PulseOutput *po, PulseMixer *pm)
+{
+	assert(po != nullptr);
+	assert(po->mixer == nullptr);
+	assert(pm != nullptr);
+
+	po->mixer = pm;
+
+	if (po->mainloop == nullptr)
+		return;
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	if (po->context != nullptr &&
+	    pa_context_get_state(po->context) == PA_CONTEXT_READY) {
+		pulse_mixer_on_connect(pm, po->context);
+
+		if (po->stream != nullptr &&
+		    pa_stream_get_state(po->stream) == PA_STREAM_READY)
+			pulse_mixer_on_change(pm, po->context, po->stream);
+	}
+
+	pa_threaded_mainloop_unlock(po->mainloop);
+}
+
+void
+pulse_output_clear_mixer(PulseOutput *po, gcc_unused PulseMixer *pm)
+{
+	assert(po != nullptr);
+	assert(pm != nullptr);
+	assert(po->mixer == pm);
+
+	po->mixer = nullptr;
+}
+
+bool
+pulse_output_set_volume(PulseOutput *po, const pa_cvolume *volume,
+			Error &error)
+{
+	pa_operation *o;
+
+	if (po->context == nullptr || po->stream == nullptr ||
+	    pa_stream_get_state(po->stream) != PA_STREAM_READY) {
+		error.Set(pulse_output_domain, "disconnected");
+		return false;
+	}
+
+	o = pa_context_set_sink_input_volume(po->context,
+					     pa_stream_get_index(po->stream),
+					     volume, nullptr, nullptr);
+	if (o == nullptr) {
+		SetError(error, po->context,
+			 "failed to set PulseAudio volume");
+		return false;
+	}
+
+	pa_operation_unref(o);
+	return true;
+}
+
+/**
+ * \brief waits for a pulseaudio operation to finish, frees it and
+ *     unlocks the mainloop
+ * \param operation the operation to wait for
+ * \return true if operation has finished normally (DONE state),
+ *     false otherwise
+ */
+static bool
+pulse_wait_for_operation(struct pa_threaded_mainloop *mainloop,
+			 struct pa_operation *operation)
+{
+	pa_operation_state_t state;
+
+	assert(mainloop != nullptr);
+	assert(operation != nullptr);
+
+	state = pa_operation_get_state(operation);
+	while (state == PA_OPERATION_RUNNING) {
+		pa_threaded_mainloop_wait(mainloop);
+		state = pa_operation_get_state(operation);
+	}
+
+	pa_operation_unref(operation);
+
+	return state == PA_OPERATION_DONE;
+}
+
+/**
+ * Callback function for stream operation.  It just sends a signal to
+ * the caller thread, to wake pulse_wait_for_operation() up.
+ */
+static void
+pulse_output_stream_success_cb(gcc_unused pa_stream *s,
+			       gcc_unused int success, void *userdata)
+{
+	PulseOutput *po = (PulseOutput *)userdata;
+
+	pa_threaded_mainloop_signal(po->mainloop, 0);
+}
+
+static void
+pulse_output_context_state_cb(struct pa_context *context, void *userdata)
+{
+	PulseOutput *po = (PulseOutput *)userdata;
+
+	switch (pa_context_get_state(context)) {
+	case PA_CONTEXT_READY:
+		if (po->mixer != nullptr)
+			pulse_mixer_on_connect(po->mixer, context);
+
+		pa_threaded_mainloop_signal(po->mainloop, 0);
+		break;
+
+	case PA_CONTEXT_TERMINATED:
+	case PA_CONTEXT_FAILED:
+		if (po->mixer != nullptr)
+			pulse_mixer_on_disconnect(po->mixer);
+
+		/* the caller thread might be waiting for these
+		   states */
+		pa_threaded_mainloop_signal(po->mainloop, 0);
+		break;
+
+	case PA_CONTEXT_UNCONNECTED:
+	case PA_CONTEXT_CONNECTING:
+	case PA_CONTEXT_AUTHORIZING:
+	case PA_CONTEXT_SETTING_NAME:
+		break;
+	}
+}
+
+static void
+pulse_output_subscribe_cb(pa_context *context,
+			  pa_subscription_event_type_t t,
+			  uint32_t idx, void *userdata)
+{
+	PulseOutput *po = (PulseOutput *)userdata;
+	pa_subscription_event_type_t facility =
+		pa_subscription_event_type_t(t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK);
+	pa_subscription_event_type_t type =
+		pa_subscription_event_type_t(t & PA_SUBSCRIPTION_EVENT_TYPE_MASK);
+
+	if (po->mixer != nullptr &&
+	    facility == PA_SUBSCRIPTION_EVENT_SINK_INPUT &&
+	    po->stream != nullptr &&
+	    pa_stream_get_state(po->stream) == PA_STREAM_READY &&
+	    idx == pa_stream_get_index(po->stream) &&
+	    (type == PA_SUBSCRIPTION_EVENT_NEW ||
+	     type == PA_SUBSCRIPTION_EVENT_CHANGE))
+		pulse_mixer_on_change(po->mixer, context, po->stream);
+}
+
+/**
+ * Attempt to connect asynchronously to the PulseAudio server.
+ *
+ * @return true on success, false on error
+ */
+static bool
+pulse_output_connect(PulseOutput *po, Error &error)
+{
+	assert(po != nullptr);
+	assert(po->context != nullptr);
+
+	if (pa_context_connect(po->context, po->server,
+			       (pa_context_flags_t)0, nullptr) < 0) {
+		SetError(error, po->context,
+			 "pa_context_connect() has failed");
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * Frees and clears the stream.
+ */
+static void
+pulse_output_delete_stream(PulseOutput *po)
+{
+	assert(po != nullptr);
+	assert(po->stream != nullptr);
+
+	pa_stream_set_suspended_callback(po->stream, nullptr, nullptr);
+
+	pa_stream_set_state_callback(po->stream, nullptr, nullptr);
+	pa_stream_set_write_callback(po->stream, nullptr, nullptr);
+
+	pa_stream_disconnect(po->stream);
+	pa_stream_unref(po->stream);
+	po->stream = nullptr;
+}
+
+/**
+ * Frees and clears the context.
+ *
+ * Caller must lock the main loop.
+ */
+static void
+pulse_output_delete_context(PulseOutput *po)
+{
+	assert(po != nullptr);
+	assert(po->context != nullptr);
+
+	pa_context_set_state_callback(po->context, nullptr, nullptr);
+	pa_context_set_subscribe_callback(po->context, nullptr, nullptr);
+
+	pa_context_disconnect(po->context);
+	pa_context_unref(po->context);
+	po->context = nullptr;
+}
+
+/**
+ * Create, set up and connect a context.
+ *
+ * Caller must lock the main loop.
+ *
+ * @return true on success, false on error
+ */
+static bool
+pulse_output_setup_context(PulseOutput *po, Error &error)
+{
+	assert(po != nullptr);
+	assert(po->mainloop != nullptr);
+
+	po->context = pa_context_new(pa_threaded_mainloop_get_api(po->mainloop),
+				     MPD_PULSE_NAME);
+	if (po->context == nullptr) {
+		error.Set(pulse_output_domain, "pa_context_new() has failed");
+		return false;
+	}
+
+	pa_context_set_state_callback(po->context,
+				      pulse_output_context_state_cb, po);
+	pa_context_set_subscribe_callback(po->context,
+					  pulse_output_subscribe_cb, po);
+
+	if (!pulse_output_connect(po, error)) {
+		pulse_output_delete_context(po);
+		return false;
+	}
+
+	return true;
+}
+
+static struct audio_output *
+pulse_output_init(const config_param &param, Error &error)
+{
+	PulseOutput *po;
+
+	g_setenv("PULSE_PROP_media.role", "music", true);
+
+	po = new PulseOutput();
+	if (!ao_base_init(&po->base, &pulse_output_plugin, param, error)) {
+		delete po;
+		return nullptr;
+	}
+
+	po->name = param.GetBlockValue("name", "mpd_pulse");
+	po->server = param.GetBlockValue("server");
+	po->sink = param.GetBlockValue("sink");
+
+	po->mixer = nullptr;
+	po->mainloop = nullptr;
+	po->context = nullptr;
+	po->stream = nullptr;
+
+	return &po->base;
+}
+
+static void
+pulse_output_finish(struct audio_output *ao)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+
+	ao_base_finish(&po->base);
+	delete po;
+}
+
+static bool
+pulse_output_enable(struct audio_output *ao, Error &error)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+
+	assert(po->mainloop == nullptr);
+	assert(po->context == nullptr);
+
+	/* create the libpulse mainloop and start the thread */
+
+	po->mainloop = pa_threaded_mainloop_new();
+	if (po->mainloop == nullptr) {
+		g_free(po);
+
+		error.Set(pulse_output_domain,
+			  "pa_threaded_mainloop_new() has failed");
+		return false;
+	}
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	if (pa_threaded_mainloop_start(po->mainloop) < 0) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		pa_threaded_mainloop_free(po->mainloop);
+		po->mainloop = nullptr;
+
+		error.Set(pulse_output_domain,
+			  "pa_threaded_mainloop_start() has failed");
+		return false;
+	}
+
+	/* create the libpulse context and connect it */
+
+	if (!pulse_output_setup_context(po, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		pa_threaded_mainloop_stop(po->mainloop);
+		pa_threaded_mainloop_free(po->mainloop);
+		po->mainloop = nullptr;
+		return false;
+	}
+
+	pa_threaded_mainloop_unlock(po->mainloop);
+
+	return true;
+}
+
+static void
+pulse_output_disable(struct audio_output *ao)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+
+	assert(po->mainloop != nullptr);
+
+	pa_threaded_mainloop_stop(po->mainloop);
+	if (po->context != nullptr)
+		pulse_output_delete_context(po);
+	pa_threaded_mainloop_free(po->mainloop);
+	po->mainloop = nullptr;
+}
+
+/**
+ * Check if the context is (already) connected, and waits if not.  If
+ * the context has been disconnected, retry to connect.
+ *
+ * Caller must lock the main loop.
+ *
+ * @return true on success, false on error
+ */
+static bool
+pulse_output_wait_connection(PulseOutput *po, Error &error)
+{
+	assert(po->mainloop != nullptr);
+
+	pa_context_state_t state;
+
+	if (po->context == nullptr && !pulse_output_setup_context(po, error))
+		return false;
+
+	while (true) {
+		state = pa_context_get_state(po->context);
+		switch (state) {
+		case PA_CONTEXT_READY:
+			/* nothing to do */
+			return true;
+
+		case PA_CONTEXT_UNCONNECTED:
+		case PA_CONTEXT_TERMINATED:
+		case PA_CONTEXT_FAILED:
+			/* failure */
+			SetError(error, po->context, "failed to connect");
+			pulse_output_delete_context(po);
+			return false;
+
+		case PA_CONTEXT_CONNECTING:
+		case PA_CONTEXT_AUTHORIZING:
+		case PA_CONTEXT_SETTING_NAME:
+			/* wait some more */
+			pa_threaded_mainloop_wait(po->mainloop);
+			break;
+		}
+	}
+}
+
+static void
+pulse_output_stream_suspended_cb(gcc_unused pa_stream *stream, void *userdata)
+{
+	PulseOutput *po = (PulseOutput *)userdata;
+
+	assert(stream == po->stream || po->stream == nullptr);
+	assert(po->mainloop != nullptr);
+
+	/* wake up the main loop to break out of the loop in
+	   pulse_output_play() */
+	pa_threaded_mainloop_signal(po->mainloop, 0);
+}
+
+static void
+pulse_output_stream_state_cb(pa_stream *stream, void *userdata)
+{
+	PulseOutput *po = (PulseOutput *)userdata;
+
+	assert(stream == po->stream || po->stream == nullptr);
+	assert(po->mainloop != nullptr);
+	assert(po->context != nullptr);
+
+	switch (pa_stream_get_state(stream)) {
+	case PA_STREAM_READY:
+		if (po->mixer != nullptr)
+			pulse_mixer_on_change(po->mixer, po->context, stream);
+
+		pa_threaded_mainloop_signal(po->mainloop, 0);
+		break;
+
+	case PA_STREAM_FAILED:
+	case PA_STREAM_TERMINATED:
+		if (po->mixer != nullptr)
+			pulse_mixer_on_disconnect(po->mixer);
+
+		pa_threaded_mainloop_signal(po->mainloop, 0);
+		break;
+
+	case PA_STREAM_UNCONNECTED:
+	case PA_STREAM_CREATING:
+		break;
+	}
+}
+
+static void
+pulse_output_stream_write_cb(gcc_unused pa_stream *stream, size_t nbytes,
+			     void *userdata)
+{
+	PulseOutput *po = (PulseOutput *)userdata;
+
+	assert(po->mainloop != nullptr);
+
+	po->writable = nbytes;
+	pa_threaded_mainloop_signal(po->mainloop, 0);
+}
+
+/**
+ * Create, set up and connect a context.
+ *
+ * Caller must lock the main loop.
+ *
+ * @return true on success, false on error
+ */
+static bool
+pulse_output_setup_stream(PulseOutput *po, const pa_sample_spec *ss,
+			  Error &error)
+{
+	assert(po != nullptr);
+	assert(po->context != nullptr);
+
+	po->stream = pa_stream_new(po->context, po->name, ss, nullptr);
+	if (po->stream == nullptr) {
+		SetError(error, po->context, "pa_stream_new() has failed");
+		return false;
+	}
+
+	pa_stream_set_suspended_callback(po->stream,
+					 pulse_output_stream_suspended_cb, po);
+
+	pa_stream_set_state_callback(po->stream,
+				     pulse_output_stream_state_cb, po);
+	pa_stream_set_write_callback(po->stream,
+				     pulse_output_stream_write_cb, po);
+
+	return true;
+}
+
+static bool
+pulse_output_open(struct audio_output *ao, AudioFormat &audio_format,
+		  Error &error)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+	pa_sample_spec ss;
+
+	assert(po->mainloop != nullptr);
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	if (po->context != nullptr) {
+		switch (pa_context_get_state(po->context)) {
+		case PA_CONTEXT_UNCONNECTED:
+		case PA_CONTEXT_TERMINATED:
+		case PA_CONTEXT_FAILED:
+			/* the connection was closed meanwhile; delete
+			   it, and pulse_output_wait_connection() will
+			   reopen it */
+			pulse_output_delete_context(po);
+			break;
+
+		case PA_CONTEXT_READY:
+		case PA_CONTEXT_CONNECTING:
+		case PA_CONTEXT_AUTHORIZING:
+		case PA_CONTEXT_SETTING_NAME:
+			break;
+		}
+	}
+
+	if (!pulse_output_wait_connection(po, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return false;
+	}
+
+	/* MPD doesn't support the other pulseaudio sample formats, so
+	   we just force MPD to send us everything as 16 bit */
+	audio_format.format = SampleFormat::S16;
+
+	ss.format = PA_SAMPLE_S16NE;
+	ss.rate = audio_format.sample_rate;
+	ss.channels = audio_format.channels;
+
+	/* create a stream .. */
+
+	if (!pulse_output_setup_stream(po, &ss, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return false;
+	}
+
+	/* .. and connect it (asynchronously) */
+
+	if (pa_stream_connect_playback(po->stream, po->sink,
+				       nullptr, pa_stream_flags_t(0),
+				       nullptr, nullptr) < 0) {
+		pulse_output_delete_stream(po);
+
+		SetError(error, po->context,
+			 "pa_stream_connect_playback() has failed");
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return false;
+	}
+
+	pa_threaded_mainloop_unlock(po->mainloop);
+
+	return true;
+}
+
+static void
+pulse_output_close(struct audio_output *ao)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+	pa_operation *o;
+
+	assert(po->mainloop != nullptr);
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	if (pa_stream_get_state(po->stream) == PA_STREAM_READY) {
+		o = pa_stream_drain(po->stream,
+				    pulse_output_stream_success_cb, po);
+		if (o == nullptr) {
+			FormatWarning(pulse_output_domain,
+				      "pa_stream_drain() has failed: %s",
+				      pa_strerror(pa_context_errno(po->context)));
+		} else
+			pulse_wait_for_operation(po->mainloop, o);
+	}
+
+	pulse_output_delete_stream(po);
+
+	if (po->context != nullptr &&
+	    pa_context_get_state(po->context) != PA_CONTEXT_READY)
+		pulse_output_delete_context(po);
+
+	pa_threaded_mainloop_unlock(po->mainloop);
+}
+
+/**
+ * Check if the stream is (already) connected, and waits if not.  The
+ * mainloop must be locked before calling this function.
+ *
+ * @return true on success, false on error
+ */
+static bool
+pulse_output_wait_stream(PulseOutput *po, Error &error)
+{
+	while (true) {
+		switch (pa_stream_get_state(po->stream)) {
+		case PA_STREAM_READY:
+			return true;
+
+		case PA_STREAM_FAILED:
+		case PA_STREAM_TERMINATED:
+		case PA_STREAM_UNCONNECTED:
+			SetError(error, po->context,
+				 "failed to connect the stream");
+			return false;
+
+		case PA_STREAM_CREATING:
+			pa_threaded_mainloop_wait(po->mainloop);
+			break;
+		}
+	}
+}
+
+/**
+ * Sets cork mode on the stream.
+ */
+static bool
+pulse_output_stream_pause(PulseOutput *po, bool pause,
+			  Error &error)
+{
+	pa_operation *o;
+
+	assert(po->mainloop != nullptr);
+	assert(po->context != nullptr);
+	assert(po->stream != nullptr);
+
+	o = pa_stream_cork(po->stream, pause,
+			   pulse_output_stream_success_cb, po);
+	if (o == nullptr) {
+		SetError(error, po->context, "pa_stream_cork() has failed");
+		return false;
+	}
+
+	if (!pulse_wait_for_operation(po->mainloop, o)) {
+		SetError(error, po->context, "pa_stream_cork() has failed");
+		return false;
+	}
+
+	return true;
+}
+
+static unsigned
+pulse_output_delay(struct audio_output *ao)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+	unsigned result = 0;
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	if (po->base.pause && pa_stream_is_corked(po->stream) &&
+	    pa_stream_get_state(po->stream) == PA_STREAM_READY)
+		/* idle while paused */
+		result = 1000;
+
+	pa_threaded_mainloop_unlock(po->mainloop);
+
+	return result;
+}
+
+static size_t
+pulse_output_play(struct audio_output *ao, const void *chunk, size_t size,
+		  Error &error)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+
+	assert(po->mainloop != nullptr);
+	assert(po->stream != nullptr);
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	/* check if the stream is (already) connected */
+
+	if (!pulse_output_wait_stream(po, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return 0;
+	}
+
+	assert(po->context != nullptr);
+
+	/* unpause if previously paused */
+
+	if (pa_stream_is_corked(po->stream) &&
+	    !pulse_output_stream_pause(po, false, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return 0;
+	}
+
+	/* wait until the server allows us to write */
+
+	while (po->writable == 0) {
+		if (pa_stream_is_suspended(po->stream)) {
+			pa_threaded_mainloop_unlock(po->mainloop);
+			error.Set(pulse_output_domain, "suspended");
+			return 0;
+		}
+
+		pa_threaded_mainloop_wait(po->mainloop);
+
+		if (pa_stream_get_state(po->stream) != PA_STREAM_READY) {
+			pa_threaded_mainloop_unlock(po->mainloop);
+			error.Set(pulse_output_domain, "disconnected");
+			return 0;
+		}
+	}
+
+	/* now write */
+
+	if (size > po->writable)
+		/* don't send more than possible */
+		size = po->writable;
+
+	po->writable -= size;
+
+	int result = pa_stream_write(po->stream, chunk, size, nullptr,
+				     0, PA_SEEK_RELATIVE);
+	pa_threaded_mainloop_unlock(po->mainloop);
+	if (result < 0) {
+		SetError(error, po->context, "pa_stream_write() failed");
+		return 0;
+	}
+
+	return size;
+}
+
+static void
+pulse_output_cancel(struct audio_output *ao)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+	pa_operation *o;
+
+	assert(po->mainloop != nullptr);
+	assert(po->stream != nullptr);
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	if (pa_stream_get_state(po->stream) != PA_STREAM_READY) {
+		/* no need to flush when the stream isn't connected
+		   yet */
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return;
+	}
+
+	assert(po->context != nullptr);
+
+	o = pa_stream_flush(po->stream, pulse_output_stream_success_cb, po);
+	if (o == nullptr) {
+		FormatWarning(pulse_output_domain,
+			      "pa_stream_flush() has failed: %s",
+			      pa_strerror(pa_context_errno(po->context)));
+		pa_threaded_mainloop_unlock(po->mainloop);
+		return;
+	}
+
+	pulse_wait_for_operation(po->mainloop, o);
+	pa_threaded_mainloop_unlock(po->mainloop);
+}
+
+static bool
+pulse_output_pause(struct audio_output *ao)
+{
+	PulseOutput *po = (PulseOutput *)ao;
+
+	assert(po->mainloop != nullptr);
+	assert(po->stream != nullptr);
+
+	pa_threaded_mainloop_lock(po->mainloop);
+
+	/* check if the stream is (already/still) connected */
+
+	Error error;
+	if (!pulse_output_wait_stream(po, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		LogError(error);
+		return false;
+	}
+
+	assert(po->context != nullptr);
+
+	/* cork the stream */
+
+	if (!pa_stream_is_corked(po->stream) &&
+	    !pulse_output_stream_pause(po, true, error)) {
+		pa_threaded_mainloop_unlock(po->mainloop);
+		LogError(error);
+		return false;
+	}
+
+	pa_threaded_mainloop_unlock(po->mainloop);
+
+	return true;
+}
+
+static bool
+pulse_output_test_default_device(void)
+{
+	bool success;
+
+	const config_param empty;
+	PulseOutput *po = (PulseOutput *)
+		pulse_output_init(empty, IgnoreError());
+	if (po == nullptr)
+		return false;
+
+	success = pulse_output_wait_connection(po, IgnoreError());
+	pulse_output_finish(&po->base);
+
+	return success;
+}
+
+const struct audio_output_plugin pulse_output_plugin = {
+	"pulse",
+	pulse_output_test_default_device,
+	pulse_output_init,
+	pulse_output_finish,
+	pulse_output_enable,
+	pulse_output_disable,
+	pulse_output_open,
+	pulse_output_close,
+	pulse_output_delay,
+	nullptr,
+	pulse_output_play,
+	nullptr,
+	pulse_output_cancel,
+	pulse_output_pause,
+
+	&pulse_mixer_plugin,
+};