Adding pulseaudio input support to chrome

media/audio/pulse/pulse_wrapper.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/audio/pulse/pulse_wrapper.h"
+
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace media {
+
+// Static function to create a PulseWrapper object and return NULL if the
+// library could not be loaded properly.
+PulseWrapper* PulseWrapper::Create() {
+  scoped_ptr<PulseWrapper> pulse(new PulseWrapper());
+  return pulse->Load() ? pulse.release() : NULL;
+}
+
+PulseWrapper::PulseWrapper()
+    : pa_threaded_mainloop_get_api_(NULL),
+      pa_threaded_mainloop_free_(NULL),
+      pa_threaded_mainloop_new_(NULL),
+      pa_threaded_mainloop_lock_(NULL),
+      pa_threaded_mainloop_signal_(NULL),
+      pa_threaded_mainloop_start_(NULL),
+      pa_threaded_mainloop_stop_(NULL),
+      pa_threaded_mainloop_unlock_(NULL),
+      pa_threaded_mainloop_wait_(NULL),
+      pa_channel_map_init_(NULL),
+      pa_context_connect_(NULL),
+      pa_context_disconnect_(NULL),
+      pa_context_errno_(NULL),
+      pa_context_get_server_info_(NULL),
+      pa_context_get_source_info_by_index_(NULL),
+      pa_context_get_source_info_list_(NULL),
+      pa_context_get_state_(NULL),
+      pa_context_new_(NULL),
+      pa_context_set_source_volume_by_index_(NULL),
+      pa_context_set_state_callback_(NULL),
+      pa_context_unref_(NULL),
+      pa_operation_get_state_(NULL),
+      pa_operation_unref_(NULL),
+      pa_stream_begin_write_(NULL),
+      pa_stream_connect_playback_(NULL),
+      pa_stream_connect_record_(NULL),
+      pa_stream_cork_(NULL),
+      pa_stream_disconnect_(NULL),
+      pa_stream_drop_(NULL),
+      pa_stream_flush_(NULL),
+      pa_stream_get_device_index_(NULL),
+      pa_stream_get_latency_(NULL),
+      pa_stream_get_state_(NULL),
+      pa_stream_new_(NULL),
+      pa_stream_peek_(NULL),
+      pa_stream_readable_size_(NULL),
+      pa_stream_set_read_callback_(NULL),
+      pa_stream_set_state_callback_(NULL),
+      pa_stream_set_write_callback_(NULL),
+      pa_stream_unref_(NULL),
+      pa_stream_write_(NULL),
+      pa_strerror_(NULL),
+      pa_cvolume_set_(NULL) {}
+
+PulseWrapper::~PulseWrapper() {}
+
+bool PulseWrapper::Load() {
+  std::string error;
+  base::NativeLibrary pulse_lib = base::LoadNativeLibrary(

[DaleCurtis, 2013/02/15 00:28:51]

Hmm, this is way different than what I was thinking you'd have to do.  Why can't
you do something like we do in media_posix?

https://code.google.com/p/chromium/codesearch#chromium/src/media/base/media_p...

You essentially just create a list of these functions in a .sigs file and use
tools/generate_stubs to generate a static library we can link against.  See

http://git.chromium.org/gitweb/?p=chromium/third_party/ffmpeg.git;a=blob;f=ch...
http://git.chromium.org/gitweb/?p=chromium/third_party/ffmpeg.git;a=blob;f=ff...

It should be simpler than maintaining this file by hand and then having to also
deal with wrapper_-> stuff.

[no longer working on chromium, 2013/02/15 16:07:33]

Simply because I don't way we have a script to do the work.

But some question about using the generate_stubs, what will happen if some of
the symbols could not be loaded properly?
We will get error and be able to fall back to ALSA?

My way is a bit painful on writing the code, but it allows us to know what has
failed and fall back.

+      FilePath("libpulse.so.0"), &error);
+  if (!error.empty()) {
+    LOG(ERROR) << "Could not open PulseAudio library: " << error;
+    return false;
+  }
+
+  pulse_lib_.Reset(pulse_lib);
+
+  if (!Bind(&pa_threaded_mainloop_get_api_, "pa_threaded_mainloop_get_api"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_free_, "pa_threaded_mainloop_free"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_new_, "pa_threaded_mainloop_new"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_lock_, "pa_threaded_mainloop_lock"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_signal_, "pa_threaded_mainloop_signal"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_start_, "pa_threaded_mainloop_start"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_stop_, "pa_threaded_mainloop_stop"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_unlock_, "pa_threaded_mainloop_unlock"))
+    return false;
+  if (!Bind(&pa_threaded_mainloop_wait_, "pa_threaded_mainloop_wait"))
+    return false;
+  if (!Bind(&pa_channel_map_init_, "pa_channel_map_init"))
+    return false;
+  if (!Bind(&pa_context_connect_, "pa_context_connect"))
+    return false;
+  if (!Bind(&pa_context_disconnect_, "pa_context_disconnect"))
+    return false;
+  if (!Bind(&pa_context_errno_, "pa_context_errno"))
+    return false;
+  if (!Bind(&pa_context_get_server_info_, "pa_context_get_server_info"))
+    return false;
+  if (!Bind(&pa_context_get_source_info_by_index_,
+            "pa_context_get_source_info_by_index"))
+    return false;
+  if (!Bind(&pa_context_get_source_info_list_,
+            "pa_context_get_source_info_list"))
+    return false;
+  if (!Bind(&pa_context_get_state_, "pa_context_get_state"))
+    return false;
+  if (!Bind(&pa_context_new_, "pa_context_new"))
+    return false;
+  if (!Bind(&pa_context_set_source_volume_by_index_,
+            "pa_context_set_source_volume_by_index"))
+    return false;
+  if (!Bind(&pa_context_set_state_callback_, "pa_context_set_state_callback"))
+    return false;
+  if (!Bind(&pa_context_unref_, "pa_context_unref"))
+    return false;
+  if (!Bind(&pa_operation_get_state_, "pa_operation_get_state"))
+    return false;
+  if (!Bind(&pa_operation_unref_, "pa_operation_unref"))
+    return false;
+  if (!Bind(&pa_stream_begin_write_, "pa_stream_begin_write"))
+    return false;
+  if (!Bind(&pa_stream_connect_playback_, "pa_stream_connect_playback"))
+    return false;
+  if (!Bind(&pa_stream_connect_record_, "pa_stream_connect_record"))
+    return false;
+  if (!Bind(&pa_stream_cork_, "pa_stream_cork"))
+    return false;
+  if (!Bind(&pa_stream_disconnect_, "pa_stream_disconnect"))
+    return false;
+  if (!Bind(&pa_stream_drop_, "pa_stream_drop"))
+    return false;
+  if (!Bind(&pa_stream_flush_, "pa_stream_flush"))
+    return false;
+  if (!Bind(&pa_stream_get_device_index_, "pa_stream_get_device_index"))
+    return false;
+  if (!Bind(&pa_stream_get_latency_, "pa_stream_get_latency"))
+    return false;
+  if (!Bind(&pa_stream_get_state_, "pa_stream_get_state"))
+    return false;
+  if (!Bind(&pa_stream_new_, "pa_stream_new"))
+    return false;
+  if (!Bind(&pa_stream_peek_, "pa_stream_peek"))
+    return false;
+  if (!Bind(&pa_stream_readable_size_, "pa_stream_readable_size"))
+    return false;
+  if (!Bind(&pa_stream_set_read_callback_, "pa_stream_set_read_callback"))
+    return false;
+  if (!Bind(&pa_stream_set_state_callback_, "pa_stream_set_state_callback"))
+    return false;
+  if (!Bind(&pa_stream_set_write_callback_, "pa_stream_set_write_callback"))
+    return false;
+  if (!Bind(&pa_stream_unref_, "pa_stream_unref"))
+    return false;
+  if (!Bind(&pa_stream_write_, "pa_stream_write"))
+    return false;
+  if (!Bind(&pa_strerror_, "pa_strerror"))
+    return false;
+  if (!Bind(&pa_cvolume_set_, "pa_cvolume_set"))
+    return false;
+
+  return true;
+}
+
+template <class T>
+bool PulseWrapper::Bind(T* function_pointer, const std::string& function_name) {
+  *function_pointer = reinterpret_cast<T>(
+      pulse_lib_.GetFunctionPointer(function_name.c_str()));
+  if (!*function_pointer) {
+    LOG(WARNING) << "Unable to bind function " << function_name;
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace media