Issue #1806 - Follow-up: Restore PulseAudio support in libcubeb.

This was incorrectly removed because we aren't using a Rustified abstraction.

3 files changed, 1707 insertions, 0 deletions

diff --git a/media/libcubeb/src/cubeb_pulse.c b/media/libcubeb/src/cubeb_pulse.c
new file mode 100644
index 0000000000..31a2f93d26
--- /dev/null
+++ b/media/libcubeb/src/cubeb_pulse.c
@@ -0,0 +1,1700 @@
+/*
+ * Copyright © 2011 Mozilla Foundation
+ *
+ * This program is made available under an ISC-style license.  See the
+ * accompanying file LICENSE for details.
+ */
+#undef NDEBUG
+#include "cubeb-internal.h"
+#include "cubeb/cubeb.h"
+#include "cubeb_mixer.h"
+#include "cubeb_strings.h"
+#include <assert.h>
+#include <dlfcn.h>
+#include <pulse/pulseaudio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef DISABLE_LIBPULSE_DLOPEN
+#define WRAP(x) x
+#else
+#define WRAP(x) cubeb_##x
+#define LIBPULSE_API_VISIT(X)                                                  \
+  X(pa_channel_map_can_balance)                                                \
+  X(pa_channel_map_init)                                                       \
+  X(pa_context_connect)                                                        \
+  X(pa_context_disconnect)                                                     \
+  X(pa_context_drain)                                                          \
+  X(pa_context_get_server_info)                                                \
+  X(pa_context_get_sink_info_by_name)                                          \
+  X(pa_context_get_sink_info_list)                                             \
+  X(pa_context_get_sink_input_info)                                            \
+  X(pa_context_get_source_info_list)                                           \
+  X(pa_context_get_state)                                                      \
+  X(pa_context_new)                                                            \
+  X(pa_context_rttime_new)                                                     \
+  X(pa_context_set_sink_input_volume)                                          \
+  X(pa_context_set_state_callback)                                             \
+  X(pa_context_unref)                                                          \
+  X(pa_cvolume_set)                                                            \
+  X(pa_cvolume_set_balance)                                                    \
+  X(pa_frame_size)                                                             \
+  X(pa_operation_get_state)                                                    \
+  X(pa_operation_unref)                                                        \
+  X(pa_proplist_gets)                                                          \
+  X(pa_rtclock_now)                                                            \
+  X(pa_stream_begin_write)                                                     \
+  X(pa_stream_cancel_write)                                                    \
+  X(pa_stream_connect_playback)                                                \
+  X(pa_stream_cork)                                                            \
+  X(pa_stream_disconnect)                                                      \
+  X(pa_stream_get_channel_map)                                                 \
+  X(pa_stream_get_index)                                                       \
+  X(pa_stream_get_latency)                                                     \
+  X(pa_stream_get_sample_spec)                                                 \
+  X(pa_stream_get_state)                                                       \
+  X(pa_stream_get_time)                                                        \
+  X(pa_stream_new)                                                             \
+  X(pa_stream_set_state_callback)                                              \
+  X(pa_stream_set_write_callback)                                              \
+  X(pa_stream_unref)                                                           \
+  X(pa_stream_update_timing_info)                                              \
+  X(pa_stream_write)                                                           \
+  X(pa_sw_volume_from_linear)                                                  \
+  X(pa_threaded_mainloop_free)                                                 \
+  X(pa_threaded_mainloop_get_api)                                              \
+  X(pa_threaded_mainloop_in_thread)                                            \
+  X(pa_threaded_mainloop_lock)                                                 \
+  X(pa_threaded_mainloop_new)                                                  \
+  X(pa_threaded_mainloop_signal)                                               \
+  X(pa_threaded_mainloop_start)                                                \
+  X(pa_threaded_mainloop_stop)                                                 \
+  X(pa_threaded_mainloop_unlock)                                               \
+  X(pa_threaded_mainloop_wait)                                                 \
+  X(pa_usec_to_bytes)                                                          \
+  X(pa_stream_set_read_callback)                                               \
+  X(pa_stream_connect_record)                                                  \
+  X(pa_stream_readable_size)                                                   \
+  X(pa_stream_writable_size)                                                   \
+  X(pa_stream_peek)                                                            \
+  X(pa_stream_drop)                                                            \
+  X(pa_stream_get_buffer_attr)                                                 \
+  X(pa_stream_get_device_name)                                                 \
+  X(pa_context_set_subscribe_callback)                                         \
+  X(pa_context_subscribe)                                                      \
+  X(pa_mainloop_api_once)                                                      \
+  X(pa_get_library_version)                                                    \
+  X(pa_channel_map_init_auto)                                                  \
+  X(pa_stream_set_name)
+
+#define MAKE_TYPEDEF(x) static typeof(x) * cubeb_##x;
+LIBPULSE_API_VISIT(MAKE_TYPEDEF);
+#undef MAKE_TYPEDEF
+#endif
+
+#if PA_CHECK_VERSION(2, 0, 0)
+static int has_pulse_v2 = 0;
+#endif
+
+static struct cubeb_ops const pulse_ops;
+
+struct cubeb_default_sink_info {
+  pa_channel_map channel_map;
+  uint32_t sample_spec_rate;
+  pa_sink_flags_t flags;
+};
+
+struct cubeb {
+  struct cubeb_ops const * ops;
+  void * libpulse;
+  pa_threaded_mainloop * mainloop;
+  pa_context * context;
+  struct cubeb_default_sink_info * default_sink_info;
+  char * context_name;
+  int error;
+  cubeb_device_collection_changed_callback output_collection_changed_callback;
+  void * output_collection_changed_user_ptr;
+  cubeb_device_collection_changed_callback input_collection_changed_callback;
+  void * input_collection_changed_user_ptr;
+  cubeb_strings * device_ids;
+};
+
+struct cubeb_stream {
+  /* Note: Must match cubeb_stream layout in cubeb.c. */
+  cubeb * context;
+  void * user_ptr;
+  /**/
+  pa_stream * output_stream;
+  pa_stream * input_stream;
+  cubeb_data_callback data_callback;
+  cubeb_state_callback state_callback;
+  pa_time_event * drain_timer;
+  pa_sample_spec output_sample_spec;
+  pa_sample_spec input_sample_spec;
+  int shutdown;
+  float volume;
+  cubeb_state state;
+};
+
+static const float PULSE_NO_GAIN = -1.0;
+
+enum cork_state { UNCORK = 0, CORK = 1 << 0, NOTIFY = 1 << 1 };
+
+static int
+intern_device_id(cubeb * ctx, char const ** id)
+{
+  char const * interned;
+
+  assert(ctx);
+  assert(id);
+
+  interned = cubeb_strings_intern(ctx->device_ids, *id);
+  if (!interned) {
+    return CUBEB_ERROR;
+  }
+
+  *id = interned;
+
+  return CUBEB_OK;
+}
+
+static void
+sink_info_callback(pa_context * context, const pa_sink_info * info, int eol,
+                   void * u)
+{
+  (void)context;
+  cubeb * ctx = u;
+  if (!eol) {
+    free(ctx->default_sink_info);
+    ctx->default_sink_info = malloc(sizeof(struct cubeb_default_sink_info));
+    memcpy(&ctx->default_sink_info->channel_map, &info->channel_map,
+           sizeof(pa_channel_map));
+    ctx->default_sink_info->sample_spec_rate = info->sample_spec.rate;
+    ctx->default_sink_info->flags = info->flags;
+  }
+  WRAP(pa_threaded_mainloop_signal)(ctx->mainloop, 0);
+}
+
+static void
+server_info_callback(pa_context * context, const pa_server_info * info,
+                     void * u)
+{
+  pa_operation * o;
+  o = WRAP(pa_context_get_sink_info_by_name)(context, info->default_sink_name,
+                                             sink_info_callback, u);
+  if (o) {
+    WRAP(pa_operation_unref)(o);
+  }
+}
+
+static void
+context_state_callback(pa_context * c, void * u)
+{
+  cubeb * ctx = u;
+  if (!PA_CONTEXT_IS_GOOD(WRAP(pa_context_get_state)(c))) {
+    ctx->error = 1;
+  }
+  WRAP(pa_threaded_mainloop_signal)(ctx->mainloop, 0);
+}
+
+static void
+context_notify_callback(pa_context * c, void * u)
+{
+  (void)c;
+  cubeb * ctx = u;
+  WRAP(pa_threaded_mainloop_signal)(ctx->mainloop, 0);
+}
+
+static void
+stream_success_callback(pa_stream * s, int success, void * u)
+{
+  (void)s;
+  (void)success;
+  cubeb_stream * stm = u;
+  WRAP(pa_threaded_mainloop_signal)(stm->context->mainloop, 0);
+}
+
+static void
+stream_state_change_callback(cubeb_stream * stm, cubeb_state s)
+{
+  stm->state = s;
+  stm->state_callback(stm, stm->user_ptr, s);
+}
+
+static void
+stream_drain_callback(pa_mainloop_api * a, pa_time_event * e,
+                      struct timeval const * tv, void * u)
+{
+  (void)a;
+  (void)tv;
+  cubeb_stream * stm = u;
+  assert(stm->drain_timer == e);
+  stream_state_change_callback(stm, CUBEB_STATE_DRAINED);
+  /* there's no pa_rttime_free, so use this instead. */
+  a->time_free(stm->drain_timer);
+  stm->drain_timer = NULL;
+  WRAP(pa_threaded_mainloop_signal)(stm->context->mainloop, 0);
+}
+
+static void
+stream_state_callback(pa_stream * s, void * u)
+{
+  cubeb_stream * stm = u;
+  if (!PA_STREAM_IS_GOOD(WRAP(pa_stream_get_state)(s))) {
+    stream_state_change_callback(stm, CUBEB_STATE_ERROR);
+  }
+  WRAP(pa_threaded_mainloop_signal)(stm->context->mainloop, 0);
+}
+
+static void
+trigger_user_callback(pa_stream * s, void const * input_data, size_t nbytes,
+                      cubeb_stream * stm)
+{
+  void * buffer;
+  size_t size;
+  int r;
+  long got;
+  size_t towrite, read_offset;
+  size_t frame_size;
+
+  frame_size = WRAP(pa_frame_size)(&stm->output_sample_spec);
+  assert(nbytes % frame_size == 0);
+
+  towrite = nbytes;
+  read_offset = 0;
+  while (towrite) {
+    size = towrite;
+    r = WRAP(pa_stream_begin_write)(s, &buffer, &size);
+    // Note: this has failed running under rr on occassion - needs
+    // investigation.
+    assert(r == 0);
+    assert(size > 0);
+    assert(size % frame_size == 0);
+
+    LOGV("Trigger user callback with output buffer size=%zd, read_offset=%zd",
+         size, read_offset);
+    got = stm->data_callback(stm, stm->user_ptr,
+                             (uint8_t const *)input_data + read_offset, buffer,
+                             size / frame_size);
+    if (got < 0) {
+      WRAP(pa_stream_cancel_write)(s);
+      stm->shutdown = 1;
+      return;
+    }
+    // If more iterations move offset of read buffer
+    if (input_data) {
+      size_t in_frame_size = WRAP(pa_frame_size)(&stm->input_sample_spec);
+      read_offset += (size / frame_size) * in_frame_size;
+    }
+
+    if (stm->volume != PULSE_NO_GAIN) {
+      uint32_t samples = size * stm->output_sample_spec.channels / frame_size;
+
+      if (stm->output_sample_spec.format == PA_SAMPLE_S16BE ||
+          stm->output_sample_spec.format == PA_SAMPLE_S16LE) {
+        short * b = buffer;
+        for (uint32_t i = 0; i < samples; i++) {
+          b[i] *= stm->volume;
+        }
+      } else {
+        float * b = buffer;
+        for (uint32_t i = 0; i < samples; i++) {
+          b[i] *= stm->volume;
+        }
+      }
+    }
+
+    r = WRAP(pa_stream_write)(s, buffer, got * frame_size, NULL, 0,
+                              PA_SEEK_RELATIVE);
+    assert(r == 0);
+
+    if ((size_t)got < size / frame_size) {
+      pa_usec_t latency = 0;
+      r = WRAP(pa_stream_get_latency)(s, &latency, NULL);
+      if (r == -PA_ERR_NODATA) {
+        /* this needs a better guess. */
+        latency = 100 * PA_USEC_PER_MSEC;
+      }
+      assert(r == 0 || r == -PA_ERR_NODATA);
+      /* pa_stream_drain is useless, see PA bug# 866. this is a workaround. */
+      /* arbitrary safety margin: double the current latency. */
+      assert(!stm->drain_timer);
+      stm->drain_timer = WRAP(pa_context_rttime_new)(
+          stm->context->context, WRAP(pa_rtclock_now)() + 2 * latency,
+          stream_drain_callback, stm);
+      stm->shutdown = 1;
+      return;
+    }
+
+    towrite -= size;
+  }
+
+  assert(towrite == 0);
+}
+
+static int
+read_from_input(pa_stream * s, void const ** buffer, size_t * size)
+{
+  size_t readable_size = WRAP(pa_stream_readable_size)(s);
+  if (readable_size > 0) {
+    if (WRAP(pa_stream_peek)(s, buffer, size) < 0) {
+      return -1;
+    }
+  }
+  return readable_size;
+}
+
+static void
+stream_write_callback(pa_stream * s, size_t nbytes, void * u)
+{
+  LOGV("Output callback to be written buffer size %zd", nbytes);
+  cubeb_stream * stm = u;
+  if (stm->shutdown || stm->state != CUBEB_STATE_STARTED) {
+    return;
+  }
+
+  if (!stm->input_stream) {
+    // Output/playback only operation.
+    // Write directly to output
+    assert(!stm->input_stream && stm->output_stream);
+    trigger_user_callback(s, NULL, nbytes, stm);
+  }
+}
+
+static void
+stream_read_callback(pa_stream * s, size_t nbytes, void * u)
+{
+  LOGV("Input callback buffer size %zd", nbytes);
+  cubeb_stream * stm = u;
+  if (stm->shutdown) {
+    return;
+  }
+
+  void const * read_data = NULL;
+  size_t read_size;
+  while (read_from_input(s, &read_data, &read_size) > 0) {
+    /* read_data can be NULL in case of a hole. */
+    if (read_data) {
+      size_t in_frame_size = WRAP(pa_frame_size)(&stm->input_sample_spec);
+      size_t read_frames = read_size / in_frame_size;
+
+      if (stm->output_stream) {
+        // input/capture + output/playback operation
+        size_t out_frame_size = WRAP(pa_frame_size)(&stm->output_sample_spec);
+        size_t write_size = read_frames * out_frame_size;
+        // Offer full duplex data for writing
+        trigger_user_callback(stm->output_stream, read_data, write_size, stm);
+      } else {
+        // input/capture only operation. Call callback directly
+        long got = stm->data_callback(stm, stm->user_ptr, read_data, NULL,
+                                      read_frames);
+        if (got < 0 || (size_t)got != read_frames) {
+          WRAP(pa_stream_cancel_write)(s);
+          stm->shutdown = 1;
+          break;
+        }
+      }
+    }
+    if (read_size > 0) {
+      WRAP(pa_stream_drop)(s);
+    }
+
+    if (stm->shutdown) {
+      return;
+    }
+  }
+}
+
+static int
+wait_until_context_ready(cubeb * ctx)
+{
+  for (;;) {
+    pa_context_state_t state = WRAP(pa_context_get_state)(ctx->context);
+    if (!PA_CONTEXT_IS_GOOD(state))
+      return -1;
+    if (state == PA_CONTEXT_READY)
+      break;
+    WRAP(pa_threaded_mainloop_wait)(ctx->mainloop);
+  }
+  return 0;
+}
+
+static int
+wait_until_io_stream_ready(pa_stream * stream, pa_threaded_mainloop * mainloop)
+{
+  if (!stream || !mainloop) {
+    return -1;
+  }
+  for (;;) {
+    pa_stream_state_t state = WRAP(pa_stream_get_state)(stream);
+    if (!PA_STREAM_IS_GOOD(state))
+      return -1;
+    if (state == PA_STREAM_READY)
+      break;
+    WRAP(pa_threaded_mainloop_wait)(mainloop);
+  }
+  return 0;
+}
+
+static int
+wait_until_stream_ready(cubeb_stream * stm)
+{
+  if (stm->output_stream &&
+      wait_until_io_stream_ready(stm->output_stream, stm->context->mainloop) ==
+          -1) {
+    return -1;
+  }
+  if (stm->input_stream &&
+      wait_until_io_stream_ready(stm->input_stream, stm->context->mainloop) ==
+          -1) {
+    return -1;
+  }
+  return 0;
+}
+
+static int
+operation_wait(cubeb * ctx, pa_stream * stream, pa_operation * o)
+{
+  while (WRAP(pa_operation_get_state)(o) == PA_OPERATION_RUNNING) {
+    WRAP(pa_threaded_mainloop_wait)(ctx->mainloop);
+    if (!PA_CONTEXT_IS_GOOD(WRAP(pa_context_get_state)(ctx->context))) {
+      return -1;
+    }
+    if (stream && !PA_STREAM_IS_GOOD(WRAP(pa_stream_get_state)(stream))) {
+      return -1;
+    }
+  }
+  return 0;
+}
+
+static void
+cork_io_stream(cubeb_stream * stm, pa_stream * io_stream, enum cork_state state)
+{
+  pa_operation * o;
+  if (!io_stream) {
+    return;
+  }
+  o = WRAP(pa_stream_cork)(io_stream, state & CORK, stream_success_callback,
+                           stm);
+  if (o) {
+    operation_wait(stm->context, io_stream, o);
+    WRAP(pa_operation_unref)(o);
+  }
+}
+
+static void
+stream_cork(cubeb_stream * stm, enum cork_state state)
+{
+  WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+  cork_io_stream(stm, stm->output_stream, state);
+  cork_io_stream(stm, stm->input_stream, state);
+  WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+
+  if (state & NOTIFY) {
+    stream_state_change_callback(stm, state & CORK ? CUBEB_STATE_STOPPED
+                                                   : CUBEB_STATE_STARTED);
+  }
+}
+
+static int
+stream_update_timing_info(cubeb_stream * stm)
+{
+  int r = -1;
+  pa_operation * o = NULL;
+  if (stm->output_stream) {
+    o = WRAP(pa_stream_update_timing_info)(stm->output_stream,
+                                           stream_success_callback, stm);
+    if (o) {
+      r = operation_wait(stm->context, stm->output_stream, o);
+      WRAP(pa_operation_unref)(o);
+    }
+    if (r != 0) {
+      return r;
+    }
+  }
+
+  if (stm->input_stream) {
+    o = WRAP(pa_stream_update_timing_info)(stm->input_stream,
+                                           stream_success_callback, stm);
+    if (o) {
+      r = operation_wait(stm->context, stm->input_stream, o);
+      WRAP(pa_operation_unref)(o);
+    }
+  }
+
+  return r;
+}
+
+static pa_channel_position_t
+cubeb_channel_to_pa_channel(cubeb_channel channel)
+{
+  switch (channel) {
+  case CHANNEL_FRONT_LEFT:
+    return PA_CHANNEL_POSITION_FRONT_LEFT;
+  case CHANNEL_FRONT_RIGHT:
+    return PA_CHANNEL_POSITION_FRONT_RIGHT;
+  case CHANNEL_FRONT_CENTER:
+    return PA_CHANNEL_POSITION_FRONT_CENTER;
+  case CHANNEL_LOW_FREQUENCY:
+    return PA_CHANNEL_POSITION_LFE;
+  case CHANNEL_BACK_LEFT:
+    return PA_CHANNEL_POSITION_REAR_LEFT;
+  case CHANNEL_BACK_RIGHT:
+    return PA_CHANNEL_POSITION_REAR_RIGHT;
+  case CHANNEL_FRONT_LEFT_OF_CENTER:
+    return PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER;
+  case CHANNEL_FRONT_RIGHT_OF_CENTER:
+    return PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER;
+  case CHANNEL_BACK_CENTER:
+    return PA_CHANNEL_POSITION_REAR_CENTER;
+  case CHANNEL_SIDE_LEFT:
+    return PA_CHANNEL_POSITION_SIDE_LEFT;
+  case CHANNEL_SIDE_RIGHT:
+    return PA_CHANNEL_POSITION_SIDE_RIGHT;
+  case CHANNEL_TOP_CENTER:
+    return PA_CHANNEL_POSITION_TOP_CENTER;
+  case CHANNEL_TOP_FRONT_LEFT:
+    return PA_CHANNEL_POSITION_TOP_FRONT_LEFT;
+  case CHANNEL_TOP_FRONT_CENTER:
+    return PA_CHANNEL_POSITION_TOP_FRONT_CENTER;
+  case CHANNEL_TOP_FRONT_RIGHT:
+    return PA_CHANNEL_POSITION_TOP_FRONT_RIGHT;
+  case CHANNEL_TOP_BACK_LEFT:
+    return PA_CHANNEL_POSITION_TOP_REAR_LEFT;
+  case CHANNEL_TOP_BACK_CENTER:
+    return PA_CHANNEL_POSITION_TOP_REAR_CENTER;
+  case CHANNEL_TOP_BACK_RIGHT:
+    return PA_CHANNEL_POSITION_TOP_REAR_RIGHT;
+  default:
+    return PA_CHANNEL_POSITION_INVALID;
+  }
+}
+
+static void
+layout_to_channel_map(cubeb_channel_layout layout, pa_channel_map * cm)
+{
+  assert(cm && layout != CUBEB_LAYOUT_UNDEFINED);
+
+  WRAP(pa_channel_map_init)(cm);
+
+  uint32_t channels = 0;
+  cubeb_channel_layout channelMap = layout;
+  for (uint32_t i = 0; channelMap != 0; ++i) {
+    uint32_t channel = (channelMap & 1) << i;
+    if (channel != 0) {
+      cm->map[channels] = cubeb_channel_to_pa_channel(channel);
+      channels++;
+    }
+    channelMap = channelMap >> 1;
+  }
+  unsigned int channels_from_layout = cubeb_channel_layout_nb_channels(layout);
+  assert(channels_from_layout <= UINT8_MAX);
+  cm->channels = (uint8_t)channels_from_layout;
+
+  // Special case single channel center mapping as mono.
+  if (cm->channels == 1 && cm->map[0] == PA_CHANNEL_POSITION_FRONT_CENTER) {
+    cm->map[0] = PA_CHANNEL_POSITION_MONO;
+  }
+}
+
+static void
+pulse_context_destroy(cubeb * ctx);
+static void
+pulse_destroy(cubeb * ctx);
+
+static int
+pulse_context_init(cubeb * ctx)
+{
+  int r;
+
+  if (ctx->context) {
+    assert(ctx->error == 1);
+    pulse_context_destroy(ctx);
+  }
+
+  ctx->context = WRAP(pa_context_new)(
+      WRAP(pa_threaded_mainloop_get_api)(ctx->mainloop), ctx->context_name);
+  if (!ctx->context) {
+    return -1;
+  }
+  WRAP(pa_context_set_state_callback)
+  (ctx->context, context_state_callback, ctx);
+
+  WRAP(pa_threaded_mainloop_lock)(ctx->mainloop);
+  r = WRAP(pa_context_connect)(ctx->context, NULL, 0, NULL);
+
+  if (r < 0 || wait_until_context_ready(ctx) != 0) {
+    WRAP(pa_threaded_mainloop_unlock)(ctx->mainloop);
+    pulse_context_destroy(ctx);
+    ctx->context = NULL;
+    return -1;
+  }
+
+  WRAP(pa_threaded_mainloop_unlock)(ctx->mainloop);
+
+  ctx->error = 0;
+
+  return 0;
+}
+
+static int
+pulse_subscribe_notifications(cubeb * context, pa_subscription_mask_t mask);
+
+/*static*/ int
+pulse_init(cubeb ** context, char const * context_name)
+{
+  void * libpulse = NULL;
+  cubeb * ctx;
+  pa_operation * o;
+
+  *context = NULL;
+
+#ifndef DISABLE_LIBPULSE_DLOPEN
+  libpulse = dlopen("libpulse.so.0", RTLD_LAZY);
+  if (!libpulse) {
+    libpulse = dlopen("libpulse.so", RTLD_LAZY);
+    if (!libpulse) {
+      return CUBEB_ERROR;
+    }
+  }
+
+#define LOAD(x)                                                                \
+  {                                                                            \
+    cubeb_##x = dlsym(libpulse, #x);                                           \
+    if (!cubeb_##x) {                                                          \
+      dlclose(libpulse);                                                       \
+      return CUBEB_ERROR;                                                      \
+    }                                                                          \
+  }
+
+  LIBPULSE_API_VISIT(LOAD);
+#undef LOAD
+#endif
+
+#if PA_CHECK_VERSION(2, 0, 0)
+  const char * version = WRAP(pa_get_library_version)();
+  has_pulse_v2 = strtol(version, NULL, 10) >= 2;
+#endif
+
+  ctx = calloc(1, sizeof(*ctx));
+  assert(ctx);
+
+  ctx->ops = &pulse_ops;
+  ctx->libpulse = libpulse;
+  if (cubeb_strings_init(&ctx->device_ids) != CUBEB_OK) {
+    pulse_destroy(ctx);
+    return CUBEB_ERROR;
+  }
+
+  ctx->mainloop = WRAP(pa_threaded_mainloop_new)();
+  ctx->default_sink_info = NULL;
+
+  WRAP(pa_threaded_mainloop_start)(ctx->mainloop);
+
+  ctx->context_name = context_name ? strdup(context_name) : NULL;
+  if (pulse_context_init(ctx) != 0) {
+    pulse_destroy(ctx);
+    return CUBEB_ERROR;
+  }
+
+  /* server_info_callback performs a second async query, which is
+     responsible for initializing default_sink_info and signalling the
+     mainloop to end the wait. */
+  WRAP(pa_threaded_mainloop_lock)(ctx->mainloop);
+  o = WRAP(pa_context_get_server_info)(ctx->context, server_info_callback, ctx);
+  if (o) {
+    operation_wait(ctx, NULL, o);
+    WRAP(pa_operation_unref)(o);
+  }
+  WRAP(pa_threaded_mainloop_unlock)(ctx->mainloop);
+
+  /* Update `default_sink_info` when the default device changes. */
+  pulse_subscribe_notifications(ctx, PA_SUBSCRIPTION_MASK_SERVER);
+
+  *context = ctx;
+
+  return CUBEB_OK;
+}
+
+static char const *
+pulse_get_backend_id(cubeb * ctx)
+{
+  (void)ctx;
+  return "pulse";
+}
+
+static int
+pulse_get_max_channel_count(cubeb * ctx, uint32_t * max_channels)
+{
+  (void)ctx;
+  assert(ctx && max_channels);
+
+  if (!ctx->default_sink_info)
+    return CUBEB_ERROR;
+
+  *max_channels = ctx->default_sink_info->channel_map.channels;
+
+  return CUBEB_OK;
+}
+
+static int
+pulse_get_preferred_sample_rate(cubeb * ctx, uint32_t * rate)
+{
+  assert(ctx && rate);
+  (void)ctx;
+
+  if (!ctx->default_sink_info)
+    return CUBEB_ERROR;
+
+  *rate = ctx->default_sink_info->sample_spec_rate;
+
+  return CUBEB_OK;
+}
+
+static int
+pulse_get_min_latency(cubeb * ctx, cubeb_stream_params params,
+                      uint32_t * latency_frames)
+{
+  (void)ctx;
+  // According to PulseAudio developers, this is a safe minimum.
+  *latency_frames = 25 * params.rate / 1000;
+
+  return CUBEB_OK;
+}
+
+static void
+pulse_context_destroy(cubeb * ctx)
+{
+  pa_operation * o;
+
+  WRAP(pa_threaded_mainloop_lock)(ctx->mainloop);
+  o = WRAP(pa_context_drain)(ctx->context, context_notify_callback, ctx);
+  if (o) {
+    operation_wait(ctx, NULL, o);
+    WRAP(pa_operation_unref)(o);
+  }
+  WRAP(pa_context_set_state_callback)(ctx->context, NULL, NULL);
+  WRAP(pa_context_disconnect)(ctx->context);
+  WRAP(pa_context_unref)(ctx->context);
+  WRAP(pa_threaded_mainloop_unlock)(ctx->mainloop);
+}
+
+static void
+pulse_destroy(cubeb * ctx)
+{
+  free(ctx->context_name);
+  if (ctx->context) {
+    pulse_context_destroy(ctx);
+  }
+
+  if (ctx->mainloop) {
+    WRAP(pa_threaded_mainloop_stop)(ctx->mainloop);
+    WRAP(pa_threaded_mainloop_free)(ctx->mainloop);
+  }
+
+  if (ctx->device_ids) {
+    cubeb_strings_destroy(ctx->device_ids);
+  }
+
+  if (ctx->libpulse) {
+    dlclose(ctx->libpulse);
+  }
+  free(ctx->default_sink_info);
+  free(ctx);
+}
+
+static void
+pulse_stream_destroy(cubeb_stream * stm);
+
+static pa_sample_format_t
+to_pulse_format(cubeb_sample_format format)
+{
+  switch (format) {
+  case CUBEB_SAMPLE_S16LE:
+    return PA_SAMPLE_S16LE;
+  case CUBEB_SAMPLE_S16BE:
+    return PA_SAMPLE_S16BE;
+  case CUBEB_SAMPLE_FLOAT32LE:
+    return PA_SAMPLE_FLOAT32LE;
+  case CUBEB_SAMPLE_FLOAT32BE:
+    return PA_SAMPLE_FLOAT32BE;
+  default:
+    return PA_SAMPLE_INVALID;
+  }
+}
+
+static cubeb_channel_layout
+pulse_default_layout_for_channels(uint32_t ch)
+{
+  assert(ch > 0 && ch <= 8);
+  switch (ch) {
+  case 1:
+    return CUBEB_LAYOUT_MONO;
+  case 2:
+    return CUBEB_LAYOUT_STEREO;
+  case 3:
+    return CUBEB_LAYOUT_3F;
+  case 4:
+    return CUBEB_LAYOUT_QUAD;
+  case 5:
+    return CUBEB_LAYOUT_3F2;
+  case 6:
+    return CUBEB_LAYOUT_3F_LFE | CHANNEL_SIDE_LEFT | CHANNEL_SIDE_RIGHT;
+  case 7:
+    return CUBEB_LAYOUT_3F3R_LFE;
+  case 8:
+    return CUBEB_LAYOUT_3F4_LFE;
+  }
+  // Never get here!
+  return CUBEB_LAYOUT_UNDEFINED;
+}
+
+static int
+create_pa_stream(cubeb_stream * stm, pa_stream ** pa_stm,
+                 cubeb_stream_params * stream_params, char const * stream_name)
+{
+  assert(stm && stream_params);
+  assert(&stm->input_stream == pa_stm ||
+         (&stm->output_stream == pa_stm &&
+          (stream_params->layout == CUBEB_LAYOUT_UNDEFINED ||
+           (stream_params->layout != CUBEB_LAYOUT_UNDEFINED &&
+            cubeb_channel_layout_nb_channels(stream_params->layout) ==
+                stream_params->channels))));
+  if (stream_params->prefs & CUBEB_STREAM_PREF_LOOPBACK) {
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+  *pa_stm = NULL;
+  pa_sample_spec ss;
+  ss.format = to_pulse_format(stream_params->format);
+  if (ss.format == PA_SAMPLE_INVALID)
+    return CUBEB_ERROR_INVALID_FORMAT;
+  ss.rate = stream_params->rate;
+  if (stream_params->channels > UINT8_MAX)
+    return CUBEB_ERROR_INVALID_FORMAT;
+  ss.channels = (uint8_t)stream_params->channels;
+
+  if (stream_params->layout == CUBEB_LAYOUT_UNDEFINED) {
+    pa_channel_map cm;
+    if (stream_params->channels <= 8 &&
+        !WRAP(pa_channel_map_init_auto)(&cm, stream_params->channels,
+                                        PA_CHANNEL_MAP_DEFAULT)) {
+      LOG("Layout undefined and PulseAudio's default layout has not been "
+          "configured, guess one.");
+      layout_to_channel_map(
+          pulse_default_layout_for_channels(stream_params->channels), &cm);
+      *pa_stm =
+          WRAP(pa_stream_new)(stm->context->context, stream_name, &ss, &cm);
+    } else {
+      LOG("Layout undefined, PulseAudio will use its default.");
+      *pa_stm =
+          WRAP(pa_stream_new)(stm->context->context, stream_name, &ss, NULL);
+    }
+  } else {
+    pa_channel_map cm;
+    layout_to_channel_map(stream_params->layout, &cm);
+    *pa_stm = WRAP(pa_stream_new)(stm->context->context, stream_name, &ss, &cm);
+  }
+  return (*pa_stm == NULL) ? CUBEB_ERROR : CUBEB_OK;
+}
+
+static pa_buffer_attr
+set_buffering_attribute(unsigned int latency_frames,
+                        pa_sample_spec * sample_spec)
+{
+  pa_buffer_attr battr;
+  battr.maxlength = -1;
+  battr.prebuf = -1;
+  battr.tlength = latency_frames * WRAP(pa_frame_size)(sample_spec);
+  battr.minreq = battr.tlength / 4;
+  battr.fragsize = battr.minreq;
+
+  LOG("Requested buffer attributes maxlength %u, tlength %u, prebuf %u, minreq "
+      "%u, fragsize %u",
+      battr.maxlength, battr.tlength, battr.prebuf, battr.minreq,
+      battr.fragsize);
+
+  return battr;
+}
+
+static int
+pulse_stream_init(cubeb * context, cubeb_stream ** stream,
+                  char const * stream_name, cubeb_devid input_device,
+                  cubeb_stream_params * input_stream_params,
+                  cubeb_devid output_device,
+                  cubeb_stream_params * output_stream_params,
+                  unsigned int latency_frames,
+                  cubeb_data_callback data_callback,
+                  cubeb_state_callback state_callback, void * user_ptr)
+{
+  cubeb_stream * stm;
+  pa_buffer_attr battr;
+  int r;
+
+  assert(context);
+
+  // If the connection failed for some reason, try to reconnect
+  if (context->error == 1 && pulse_context_init(context) != 0) {
+    return CUBEB_ERROR;
+  }
+
+  *stream = NULL;
+
+  stm = calloc(1, sizeof(*stm));
+  assert(stm);
+
+  stm->context = context;
+  stm->data_callback = data_callback;
+  stm->state_callback = state_callback;
+  stm->user_ptr = user_ptr;
+  stm->volume = PULSE_NO_GAIN;
+  stm->state = -1;
+  assert(stm->shutdown == 0);
+
+  WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+  if (output_stream_params) {
+    r = create_pa_stream(stm, &stm->output_stream, output_stream_params,
+                         stream_name);
+    if (r != CUBEB_OK) {
+      WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+      pulse_stream_destroy(stm);
+      return r;
+    }
+
+    stm->output_sample_spec =
+        *(WRAP(pa_stream_get_sample_spec)(stm->output_stream));
+
+    WRAP(pa_stream_set_state_callback)
+    (stm->output_stream, stream_state_callback, stm);
+    WRAP(pa_stream_set_write_callback)
+    (stm->output_stream, stream_write_callback, stm);
+
+    battr = set_buffering_attribute(latency_frames, &stm->output_sample_spec);
+    WRAP(pa_stream_connect_playback)
+    (stm->output_stream, (char const *)output_device, &battr,
+     PA_STREAM_AUTO_TIMING_UPDATE | PA_STREAM_INTERPOLATE_TIMING |
+         PA_STREAM_START_CORKED | PA_STREAM_ADJUST_LATENCY,
+     NULL, NULL);
+  }
+
+  // Set up input stream
+  if (input_stream_params) {
+    r = create_pa_stream(stm, &stm->input_stream, input_stream_params,
+                         stream_name);
+    if (r != CUBEB_OK) {
+      WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+      pulse_stream_destroy(stm);
+      return r;
+    }
+
+    stm->input_sample_spec =
+        *(WRAP(pa_stream_get_sample_spec)(stm->input_stream));
+
+    WRAP(pa_stream_set_state_callback)
+    (stm->input_stream, stream_state_callback, stm);
+    WRAP(pa_stream_set_read_callback)
+    (stm->input_stream, stream_read_callback, stm);
+
+    battr = set_buffering_attribute(latency_frames, &stm->input_sample_spec);
+    WRAP(pa_stream_connect_record)
+    (stm->input_stream, (char const *)input_device, &battr,
+     PA_STREAM_AUTO_TIMING_UPDATE | PA_STREAM_INTERPOLATE_TIMING |
+         PA_STREAM_START_CORKED | PA_STREAM_ADJUST_LATENCY);
+  }
+
+  r = wait_until_stream_ready(stm);
+  if (r == 0) {
+    /* force a timing update now, otherwise timing info does not become valid
+       until some point after initialization has completed. */
+    r = stream_update_timing_info(stm);
+  }
+
+  WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+
+  if (r != 0) {
+    pulse_stream_destroy(stm);
+    return CUBEB_ERROR;
+  }
+
+  if (g_cubeb_log_level) {
+    if (output_stream_params) {
+      const pa_buffer_attr * output_att;
+      output_att = WRAP(pa_stream_get_buffer_attr)(stm->output_stream);
+      LOG("Output buffer attributes maxlength %u, tlength %u, prebuf %u, "
+          "minreq %u, fragsize %u",
+          output_att->maxlength, output_att->tlength, output_att->prebuf,
+          output_att->minreq, output_att->fragsize);
+    }
+
+    if (input_stream_params) {
+      const pa_buffer_attr * input_att;
+      input_att = WRAP(pa_stream_get_buffer_attr)(stm->input_stream);
+      LOG("Input buffer attributes maxlength %u, tlength %u, prebuf %u, minreq "
+          "%u, fragsize %u",
+          input_att->maxlength, input_att->tlength, input_att->prebuf,
+          input_att->minreq, input_att->fragsize);
+    }
+  }
+
+  *stream = stm;
+  LOG("Cubeb stream (%p) init successful.", *stream);
+
+  return CUBEB_OK;
+}
+
+static void
+pulse_stream_destroy(cubeb_stream * stm)
+{
+  stream_cork(stm, CORK);
+
+  WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+  if (stm->output_stream) {
+
+    if (stm->drain_timer) {
+      /* there's no pa_rttime_free, so use this instead. */
+      WRAP(pa_threaded_mainloop_get_api)
+      (stm->context->mainloop)->time_free(stm->drain_timer);
+    }
+
+    WRAP(pa_stream_set_state_callback)(stm->output_stream, NULL, NULL);
+    WRAP(pa_stream_set_write_callback)(stm->output_stream, NULL, NULL);
+    WRAP(pa_stream_disconnect)(stm->output_stream);
+    WRAP(pa_stream_unref)(stm->output_stream);
+  }
+
+  if (stm->input_stream) {
+    WRAP(pa_stream_set_state_callback)(stm->input_stream, NULL, NULL);
+    WRAP(pa_stream_set_read_callback)(stm->input_stream, NULL, NULL);
+    WRAP(pa_stream_disconnect)(stm->input_stream);
+    WRAP(pa_stream_unref)(stm->input_stream);
+  }
+  WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+
+  LOG("Cubeb stream (%p) destroyed successfully.", stm);
+  free(stm);
+}
+
+static void
+pulse_defer_event_cb(pa_mainloop_api * a, void * userdata)
+{
+  (void)a;
+  cubeb_stream * stm = userdata;
+  if (stm->shutdown) {
+    return;
+  }
+  size_t writable_size = WRAP(pa_stream_writable_size)(stm->output_stream);
+  trigger_user_callback(stm->output_stream, NULL, writable_size, stm);
+}
+
+static int
+pulse_stream_start(cubeb_stream * stm)
+{
+  stm->shutdown = 0;
+  stream_cork(stm, UNCORK | NOTIFY);
+
+  if (stm->output_stream && !stm->input_stream) {
+    /* On output only case need to manually call user cb once in order to make
+     * things roll. This is done via a defer event in order to execute it
+     * from PA server thread. */
+    WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+    WRAP(pa_mainloop_api_once)
+    (WRAP(pa_threaded_mainloop_get_api)(stm->context->mainloop),
+     pulse_defer_event_cb, stm);
+    WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+  }
+
+  LOG("Cubeb stream (%p) started successfully.", stm);
+  return CUBEB_OK;
+}
+
+static int
+pulse_stream_stop(cubeb_stream * stm)
+{
+  WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+  stm->shutdown = 1;
+  // If draining is taking place wait to finish
+  while (stm->drain_timer) {
+    WRAP(pa_threaded_mainloop_wait)(stm->context->mainloop);
+  }
+  WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+
+  stream_cork(stm, CORK | NOTIFY);
+  LOG("Cubeb stream (%p) stopped successfully.", stm);
+  return CUBEB_OK;
+}
+
+static int
+pulse_stream_get_position(cubeb_stream * stm, uint64_t * position)
+{
+  int r, in_thread;
+  pa_usec_t r_usec;
+  uint64_t bytes;
+
+  if (!stm || !stm->output_stream) {
+    return CUBEB_ERROR;
+  }
+
+  in_thread = WRAP(pa_threaded_mainloop_in_thread)(stm->context->mainloop);
+
+  if (!in_thread) {
+    WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+  }
+  r = WRAP(pa_stream_get_time)(stm->output_stream, &r_usec);
+  if (!in_thread) {
+    WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+  }
+
+  if (r != 0) {
+    return CUBEB_ERROR;
+  }
+
+  bytes = WRAP(pa_usec_to_bytes)(r_usec, &stm->output_sample_spec);
+  *position = bytes / WRAP(pa_frame_size)(&stm->output_sample_spec);
+
+  return CUBEB_OK;
+}
+
+static int
+pulse_stream_get_latency(cubeb_stream * stm, uint32_t * latency)
+{
+  pa_usec_t r_usec;
+  int negative, r;
+
+  if (!stm || !stm->output_stream) {
+    return CUBEB_ERROR;
+  }
+
+  r = WRAP(pa_stream_get_latency)(stm->output_stream, &r_usec, &negative);
+  assert(!negative);
+  if (r) {
+    return CUBEB_ERROR;
+  }
+
+  *latency = r_usec * stm->output_sample_spec.rate / PA_USEC_PER_SEC;
+  return CUBEB_OK;
+}
+
+static void
+volume_success(pa_context * c, int success, void * userdata)
+{
+  (void)success;
+  (void)c;
+  cubeb_stream * stream = userdata;
+  assert(success);
+  WRAP(pa_threaded_mainloop_signal)(stream->context->mainloop, 0);
+}
+
+static void
+rename_success(pa_stream * s, int success, void * userdata)
+{
+  cubeb_stream * stream = userdata;
+  assert(success);
+  WRAP(pa_threaded_mainloop_signal)(stream->context->mainloop, 0);
+}
+
+static int
+pulse_stream_set_volume(cubeb_stream * stm, float volume)
+{
+  uint32_t index;
+  pa_operation * op;
+  pa_volume_t vol;
+  pa_cvolume cvol;
+  const pa_sample_spec * ss;
+  cubeb * ctx;
+
+  if (!stm->output_stream) {
+    return CUBEB_ERROR;
+  }
+
+  WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+
+  /* if the pulse daemon is configured to use flat volumes,
+   * apply our own gain instead of changing the input volume on the sink. */
+  ctx = stm->context;
+  if (ctx->default_sink_info &&
+      (ctx->default_sink_info->flags & PA_SINK_FLAT_VOLUME)) {
+    stm->volume = volume;
+  } else {
+    ss = WRAP(pa_stream_get_sample_spec)(stm->output_stream);
+
+    vol = WRAP(pa_sw_volume_from_linear)(volume);
+    WRAP(pa_cvolume_set)(&cvol, ss->channels, vol);
+
+    index = WRAP(pa_stream_get_index)(stm->output_stream);
+
+    op = WRAP(pa_context_set_sink_input_volume)(ctx->context, index, &cvol,
+                                                volume_success, stm);
+    if (op) {
+      operation_wait(ctx, stm->output_stream, op);
+      WRAP(pa_operation_unref)(op);
+    }
+  }
+
+  WRAP(pa_threaded_mainloop_unlock)(ctx->mainloop);
+
+  return CUBEB_OK;
+}
+
+static int
+pulse_stream_set_name(cubeb_stream * stm, char const * stream_name)
+{
+  if (!stm || !stm->output_stream) {
+    return CUBEB_ERROR;
+  }
+
+  WRAP(pa_threaded_mainloop_lock)(stm->context->mainloop);
+
+  pa_operation * op = WRAP(pa_stream_set_name)(stm->output_stream, stream_name,
+                                               rename_success, stm);
+
+  if (op) {
+    operation_wait(stm->context, stm->output_stream, op);
+    WRAP(pa_operation_unref)(op);
+  }
+
+  WRAP(pa_threaded_mainloop_unlock)(stm->context->mainloop);
+
+  return CUBEB_OK;
+}
+
+typedef struct {
+  char * default_sink_name;
+  char * default_source_name;
+
+  cubeb_device_info * devinfo;
+  uint32_t max;
+  uint32_t count;
+  cubeb * context;
+} pulse_dev_list_data;
+
+static cubeb_device_fmt
+pulse_format_to_cubeb_format(pa_sample_format_t format)
+{
+  switch (format) {
+  case PA_SAMPLE_S16LE:
+    return CUBEB_DEVICE_FMT_S16LE;
+  case PA_SAMPLE_S16BE:
+    return CUBEB_DEVICE_FMT_S16BE;
+  case PA_SAMPLE_FLOAT32LE:
+    return CUBEB_DEVICE_FMT_F32LE;
+  case PA_SAMPLE_FLOAT32BE:
+    return CUBEB_DEVICE_FMT_F32BE;
+  default:
+    return CUBEB_DEVICE_FMT_F32NE;
+  }
+}
+
+static void
+pulse_ensure_dev_list_data_list_size(pulse_dev_list_data * list_data)
+{
+  if (list_data->count == list_data->max) {
+    list_data->max += 8;
+    list_data->devinfo =
+        realloc(list_data->devinfo, sizeof(cubeb_device_info) * list_data->max);
+  }
+}
+
+static cubeb_device_state
+pulse_get_state_from_sink_port(pa_sink_port_info * info)
+{
+  if (info != NULL) {
+#if PA_CHECK_VERSION(2, 0, 0)
+    if (has_pulse_v2 && info->available == PA_PORT_AVAILABLE_NO)
+      return CUBEB_DEVICE_STATE_UNPLUGGED;
+    else /*if (info->available == PA_PORT_AVAILABLE_YES) + UNKNOWN */
+#endif
+      return CUBEB_DEVICE_STATE_ENABLED;
+  }
+
+  return CUBEB_DEVICE_STATE_ENABLED;
+}
+
+static void
+pulse_sink_info_cb(pa_context * context, const pa_sink_info * info, int eol,
+                   void * user_data)
+{
+  pulse_dev_list_data * list_data = user_data;
+  cubeb_device_info * devinfo;
+  char const * prop = NULL;
+  char const * device_id = NULL;
+
+  (void)context;
+
+  if (eol) {
+    WRAP(pa_threaded_mainloop_signal)(list_data->context->mainloop, 0);
+    return;
+  }
+
+  if (info == NULL)
+    return;
+
+  device_id = info->name;
+  if (intern_device_id(list_data->context, &device_id) != CUBEB_OK) {
+    assert(NULL);
+    return;
+  }
+
+  pulse_ensure_dev_list_data_list_size(list_data);
+  devinfo = &list_data->devinfo[list_data->count];
+  memset(devinfo, 0, sizeof(cubeb_device_info));
+
+  devinfo->device_id = device_id;
+  devinfo->devid = (cubeb_devid)devinfo->device_id;
+  devinfo->friendly_name = strdup(info->description);
+  prop = WRAP(pa_proplist_gets)(info->proplist, "sysfs.path");
+  if (prop)
+    devinfo->group_id = strdup(prop);
+  prop = WRAP(pa_proplist_gets)(info->proplist, "device.vendor.name");
+  if (prop)
+    devinfo->vendor_name = strdup(prop);
+
+  devinfo->type = CUBEB_DEVICE_TYPE_OUTPUT;
+  devinfo->state = pulse_get_state_from_sink_port(info->active_port);
+  devinfo->preferred = (strcmp(info->name, list_data->default_sink_name) == 0)
+                           ? CUBEB_DEVICE_PREF_ALL
+                           : CUBEB_DEVICE_PREF_NONE;
+
+  devinfo->format = CUBEB_DEVICE_FMT_ALL;
+  devinfo->default_format =
+      pulse_format_to_cubeb_format(info->sample_spec.format);
+  devinfo->max_channels = info->channel_map.channels;
+  devinfo->min_rate = 1;
+  devinfo->max_rate = PA_RATE_MAX;
+  devinfo->default_rate = info->sample_spec.rate;
+
+  devinfo->latency_lo = 0;
+  devinfo->latency_hi = 0;
+
+  list_data->count += 1;
+}
+
+static cubeb_device_state
+pulse_get_state_from_source_port(pa_source_port_info * info)
+{
+  if (info != NULL) {
+#if PA_CHECK_VERSION(2, 0, 0)
+    if (has_pulse_v2 && info->available == PA_PORT_AVAILABLE_NO)
+      return CUBEB_DEVICE_STATE_UNPLUGGED;
+    else /*if (info->available == PA_PORT_AVAILABLE_YES) + UNKNOWN */
+#endif
+      return CUBEB_DEVICE_STATE_ENABLED;
+  }
+
+  return CUBEB_DEVICE_STATE_ENABLED;
+}
+
+static void
+pulse_source_info_cb(pa_context * context, const pa_source_info * info, int eol,
+                     void * user_data)
+{
+  pulse_dev_list_data * list_data = user_data;
+  cubeb_device_info * devinfo;
+  char const * prop = NULL;
+  char const * device_id = NULL;
+
+  (void)context;
+
+  if (eol) {
+    WRAP(pa_threaded_mainloop_signal)(list_data->context->mainloop, 0);
+    return;
+  }
+
+  device_id = info->name;
+  if (intern_device_id(list_data->context, &device_id) != CUBEB_OK) {
+    assert(NULL);
+    return;
+  }
+
+  pulse_ensure_dev_list_data_list_size(list_data);
+  devinfo = &list_data->devinfo[list_data->count];
+  memset(devinfo, 0, sizeof(cubeb_device_info));
+
+  devinfo->device_id = device_id;
+  devinfo->devid = (cubeb_devid)devinfo->device_id;
+  devinfo->friendly_name = strdup(info->description);
+  prop = WRAP(pa_proplist_gets)(info->proplist, "sysfs.path");
+  if (prop)
+    devinfo->group_id = strdup(prop);
+  prop = WRAP(pa_proplist_gets)(info->proplist, "device.vendor.name");
+  if (prop)
+    devinfo->vendor_name = strdup(prop);
+
+  devinfo->type = CUBEB_DEVICE_TYPE_INPUT;
+  devinfo->state = pulse_get_state_from_source_port(info->active_port);
+  devinfo->preferred = (strcmp(info->name, list_data->default_source_name) == 0)
+                           ? CUBEB_DEVICE_PREF_ALL
+                           : CUBEB_DEVICE_PREF_NONE;
+
+  devinfo->format = CUBEB_DEVICE_FMT_ALL;
+  devinfo->default_format =
+      pulse_format_to_cubeb_format(info->sample_spec.format);
+  devinfo->max_channels = info->channel_map.channels;
+  devinfo->min_rate = 1;
+  devinfo->max_rate = PA_RATE_MAX;
+  devinfo->default_rate = info->sample_spec.rate;
+
+  devinfo->latency_lo = 0;
+  devinfo->latency_hi = 0;
+
+  list_data->count += 1;
+}
+
+static void
+pulse_server_info_cb(pa_context * c, const pa_server_info * i, void * userdata)
+{
+  pulse_dev_list_data * list_data = userdata;
+
+  (void)c;
+
+  free(list_data->default_sink_name);
+  free(list_data->default_source_name);
+  list_data->default_sink_name =
+      i->default_sink_name ? strdup(i->default_sink_name) : NULL;
+  list_data->default_source_name =
+      i->default_source_name ? strdup(i->default_source_name) : NULL;
+
+  WRAP(pa_threaded_mainloop_signal)(list_data->context->mainloop, 0);
+}
+
+static int
+pulse_enumerate_devices(cubeb * context, cubeb_device_type type,
+                        cubeb_device_collection * collection)
+{
+  pulse_dev_list_data user_data = {NULL, NULL, NULL, 0, 0, context};
+  pa_operation * o;
+
+  WRAP(pa_threaded_mainloop_lock)(context->mainloop);
+
+  o = WRAP(pa_context_get_server_info)(context->context, pulse_server_info_cb,
+                                       &user_data);
+  if (o) {
+    operation_wait(context, NULL, o);
+    WRAP(pa_operation_unref)(o);
+  }
+
+  if (type & CUBEB_DEVICE_TYPE_OUTPUT) {
+    o = WRAP(pa_context_get_sink_info_list)(context->context,
+                                            pulse_sink_info_cb, &user_data);
+    if (o) {
+      operation_wait(context, NULL, o);
+      WRAP(pa_operation_unref)(o);
+    }
+  }
+
+  if (type & CUBEB_DEVICE_TYPE_INPUT) {
+    o = WRAP(pa_context_get_source_info_list)(context->context,
+                                              pulse_source_info_cb, &user_data);
+    if (o) {
+      operation_wait(context, NULL, o);
+      WRAP(pa_operation_unref)(o);
+    }
+  }
+
+  WRAP(pa_threaded_mainloop_unlock)(context->mainloop);
+
+  collection->device = user_data.devinfo;
+  collection->count = user_data.count;
+
+  free(user_data.default_sink_name);
+  free(user_data.default_source_name);
+  return CUBEB_OK;
+}
+
+static int
+pulse_device_collection_destroy(cubeb * ctx,
+                                cubeb_device_collection * collection)
+{
+  size_t n;
+
+  for (n = 0; n < collection->count; n++) {
+    free((void *)collection->device[n].friendly_name);
+    free((void *)collection->device[n].vendor_name);
+    free((void *)collection->device[n].group_id);
+  }
+
+  free(collection->device);
+  return CUBEB_OK;
+}
+
+static int
+pulse_stream_get_current_device(cubeb_stream * stm,
+                                cubeb_device ** const device)
+{
+#if PA_CHECK_VERSION(0, 9, 8)
+  *device = calloc(1, sizeof(cubeb_device));
+  if (*device == NULL)
+    return CUBEB_ERROR;
+
+  if (stm->input_stream) {
+    const char * name = WRAP(pa_stream_get_device_name)(stm->input_stream);
+    (*device)->input_name = (name == NULL) ? NULL : strdup(name);
+  }
+
+  if (stm->output_stream) {
+    const char * name = WRAP(pa_stream_get_device_name)(stm->output_stream);
+    (*device)->output_name = (name == NULL) ? NULL : strdup(name);
+  }
+
+  return CUBEB_OK;
+#else
+  return CUBEB_ERROR_NOT_SUPPORTED;
+#endif
+}
+
+static int
+pulse_stream_device_destroy(cubeb_stream * stream, cubeb_device * device)
+{
+  (void)stream;
+  free(device->input_name);
+  free(device->output_name);
+  free(device);
+  return CUBEB_OK;
+}
+
+static void
+pulse_subscribe_callback(pa_context * ctx, pa_subscription_event_type_t t,
+                         uint32_t index, void * userdata)
+{
+  (void)ctx;
+  cubeb * context = userdata;
+
+  switch (t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) {
+  case PA_SUBSCRIPTION_EVENT_SERVER:
+    if ((t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) == PA_SUBSCRIPTION_EVENT_CHANGE) {
+      LOG("Server changed %d", index);
+      WRAP(pa_context_get_server_info)
+      (context->context, server_info_callback, context);
+    }
+    break;
+  case PA_SUBSCRIPTION_EVENT_SOURCE:
+  case PA_SUBSCRIPTION_EVENT_SINK:
+
+    if (g_cubeb_log_level) {
+      if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) ==
+              PA_SUBSCRIPTION_EVENT_SOURCE &&
+          (t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) ==
+              PA_SUBSCRIPTION_EVENT_REMOVE) {
+        LOG("Removing source index %d", index);
+      } else if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) ==
+                     PA_SUBSCRIPTION_EVENT_SOURCE &&
+                 (t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) ==
+                     PA_SUBSCRIPTION_EVENT_NEW) {
+        LOG("Adding source index %d", index);
+      }
+      if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) ==
+              PA_SUBSCRIPTION_EVENT_SINK &&
+          (t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) ==
+              PA_SUBSCRIPTION_EVENT_REMOVE) {
+        LOG("Removing sink index %d", index);
+      } else if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) ==
+                     PA_SUBSCRIPTION_EVENT_SINK &&
+                 (t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) ==
+                     PA_SUBSCRIPTION_EVENT_NEW) {
+        LOG("Adding sink index %d", index);
+      }
+    }
+
+    if ((t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) == PA_SUBSCRIPTION_EVENT_REMOVE ||
+        (t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) == PA_SUBSCRIPTION_EVENT_NEW) {
+      if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) ==
+          PA_SUBSCRIPTION_EVENT_SOURCE) {
+        context->input_collection_changed_callback(
+            context, context->input_collection_changed_user_ptr);
+      }
+      if ((t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) ==
+          PA_SUBSCRIPTION_EVENT_SINK) {
+        context->output_collection_changed_callback(
+            context, context->output_collection_changed_user_ptr);
+      }
+    }
+    break;
+  }
+}
+
+static void
+subscribe_success(pa_context * c, int success, void * userdata)
+{
+  (void)c;
+  cubeb * context = userdata;
+  assert(success);
+  WRAP(pa_threaded_mainloop_signal)(context->mainloop, 0);
+}
+
+static int
+pulse_subscribe_notifications(cubeb * context, pa_subscription_mask_t mask)
+{
+  WRAP(pa_threaded_mainloop_lock)(context->mainloop);
+
+  WRAP(pa_context_set_subscribe_callback)
+  (context->context, pulse_subscribe_callback, context);
+
+  pa_operation * o;
+  o = WRAP(pa_context_subscribe)(context->context, mask, subscribe_success,
+                                 context);
+  if (o == NULL) {
+    WRAP(pa_threaded_mainloop_unlock)(context->mainloop);
+    LOG("Context subscribe failed");
+    return CUBEB_ERROR;
+  }
+  operation_wait(context, NULL, o);
+  WRAP(pa_operation_unref)(o);
+
+  WRAP(pa_threaded_mainloop_unlock)(context->mainloop);
+
+  return CUBEB_OK;
+}
+
+static int
+pulse_register_device_collection_changed(
+    cubeb * context, cubeb_device_type devtype,
+    cubeb_device_collection_changed_callback collection_changed_callback,
+    void * user_ptr)
+{
+  if (devtype & CUBEB_DEVICE_TYPE_INPUT) {
+    context->input_collection_changed_callback = collection_changed_callback;
+    context->input_collection_changed_user_ptr = user_ptr;
+  }
+  if (devtype & CUBEB_DEVICE_TYPE_OUTPUT) {
+    context->output_collection_changed_callback = collection_changed_callback;
+    context->output_collection_changed_user_ptr = user_ptr;
+  }
+
+  pa_subscription_mask_t mask = PA_SUBSCRIPTION_MASK_NULL;
+  if (context->input_collection_changed_callback) {
+    /* Input added or removed */
+    mask |= PA_SUBSCRIPTION_MASK_SOURCE;
+  }
+  if (context->output_collection_changed_callback) {
+    /* Output added or removed */
+    mask |= PA_SUBSCRIPTION_MASK_SINK;
+  }
+  /* Default device changed, this is always registered in order to update the
+   * `default_sink_info` when the default device changes. */
+  mask |= PA_SUBSCRIPTION_MASK_SERVER;
+
+  return pulse_subscribe_notifications(context, mask);
+}
+
+static struct cubeb_ops const pulse_ops = {
+    .init = pulse_init,
+    .get_backend_id = pulse_get_backend_id,
+    .get_max_channel_count = pulse_get_max_channel_count,
+    .get_min_latency = pulse_get_min_latency,
+    .get_preferred_sample_rate = pulse_get_preferred_sample_rate,
+    .enumerate_devices = pulse_enumerate_devices,
+    .device_collection_destroy = pulse_device_collection_destroy,
+    .destroy = pulse_destroy,
+    .stream_init = pulse_stream_init,
+    .stream_destroy = pulse_stream_destroy,
+    .stream_start = pulse_stream_start,
+    .stream_stop = pulse_stream_stop,
+    .stream_get_position = pulse_stream_get_position,
+    .stream_get_latency = pulse_stream_get_latency,
+    .stream_get_input_latency = NULL,
+    .stream_set_volume = pulse_stream_set_volume,
+    .stream_set_name = pulse_stream_set_name,
+    .stream_get_current_device = pulse_stream_get_current_device,
+    .stream_device_destroy = pulse_stream_device_destroy,
+    .stream_register_device_changed_callback = NULL,
+    .register_device_collection_changed =
+        pulse_register_device_collection_changed};
diff --git a/media/libcubeb/src/moz.build b/media/libcubeb/src/moz.build
index bba0d5f8b5..50fffb6ff6 100644
--- a/media/libcubeb/src/moz.build
+++ b/media/libcubeb/src/moz.build
@@ -27,6 +27,12 @@ if CONFIG['MOZ_PULSEAUDIO'] or CONFIG['MOZ_JACK']:
         'cubeb_resampler.cpp',
     ]
 
+if CONFIG['MOZ_PULSEAUDIO']:
+    SOURCES += [
+        'cubeb_pulse.c',
+    ]
+    DEFINES['USE_PULSE'] = True
+
 if CONFIG['MOZ_JACK']:
     SOURCES += [
         'cubeb_jack.cpp',
diff --git a/media/libcubeb/update.sh b/media/libcubeb/update.sh
index 4229524b5e..14b608a4e3 100755
--- a/media/libcubeb/update.sh
+++ b/media/libcubeb/update.sh
@@ -20,6 +20,7 @@ cp $1/src/cubeb_log.h src
 cp $1/src/cubeb_mixer.cpp src
 cp $1/src/cubeb_mixer.h src
 cp $1/src/cubeb_opensl.c src
+cp $1/src/cubeb_pulse.c src
 cp $1/src/cubeb_android.h src
 cp $1/src/cubeb-jni.cpp src
 cp $1/src/cubeb-jni.h src