Add GetAssociatedOutputDeviceID support to pulse.

media/audio/pulse/pulse_util.cc

Index: media/audio/pulse/pulse_util.cc
diff --git a/media/audio/pulse/pulse_util.cc b/media/audio/pulse/pulse_util.cc
index d5c699a09e28a821fd1e7107ca1cd6be9858d24a..0209edc35a58bbf7c0c1cb2411aa8e0835324694 100644
--- a/media/audio/pulse/pulse_util.cc
+++ b/media/audio/pulse/pulse_util.cc
@@ -12,6 +12,8 @@
 #include "media/audio/audio_device_description.h"
 #include "media/base/audio_parameters.h"
 
+int strcmp(const char* s1, const char* s2);
+
 namespace media {
 
 namespace pulse {
@@ -68,6 +70,60 @@ class ScopedPropertyList {
   DISALLOW_COPY_AND_ASSIGN(ScopedPropertyList);
 };
 
+struct InputBusData {
+  InputBusData(pa_threaded_mainloop* loop, const std::string& name)
+      : loop_(loop), name_(name), bus_() {}
+
+  pa_threaded_mainloop* loop_;
+  const std::string& name_;
+  std::string bus_;
+};
+
+struct OutputBusData {
+  OutputBusData(pa_threaded_mainloop* loop, const std::string& bus)
+      : loop_(loop), name_(), bus_(bus) {}
+
+  pa_threaded_mainloop* loop_;
+  std::string name_;
+  const std::string& bus_;
+};
+
+void InputBusCallback(pa_context* context,
+                      const pa_source_info* info,
+                      int error,
+                      void* user_data) {
+  InputBusData* data = reinterpret_cast<InputBusData*>(user_data);
+
+  if (error) {
+    // We have checked all the devices now.
+    pa_threaded_mainloop_signal(data->loop_, 0);
+    return;
+  }
+
+  if (strcmp(info->name, data->name_.c_str()) == 0 &&
+      pa_proplist_contains(info->proplist, PA_PROP_DEVICE_BUS)) {
+    data->bus_ = pa_proplist_gets(info->proplist, PA_PROP_DEVICE_BUS);
+  }
+}
+
+void OutputBusCallback(pa_context* context,
+                       const pa_sink_info* info,
+                       int error,
+                       void* user_data) {
+  OutputBusData* data = reinterpret_cast<OutputBusData*>(user_data);
+
+  if (error) {
+    // We have checked all the devices now.
+    pa_threaded_mainloop_signal(data->loop_, 0);
+    return;
+  }
+
+  if (pa_proplist_contains(info->proplist, PA_PROP_DEVICE_BUS) &&
+      strcmp(pa_proplist_gets(info->proplist, PA_PROP_DEVICE_BUS),
+             data->bus_.c_str()) == 0) {
+    data->name_ = info->name;
+  }
+}
 }  // namespace
 
 // static, pa_stream_success_cb_t
@@ -355,6 +411,32 @@ bool CreateOutputStream(pa_threaded_mainloop** mainloop,
   return true;
 }
 
+std::string GetBusOfInput(const std::string& name,
+                          pa_threaded_mainloop* input_mainloop,
+                          pa_context* input_context) {
+  DCHECK(input_mainloop);
+  DCHECK(input_context);
+  AutoPulseLock auto_lock(input_mainloop);
+  InputBusData data(input_mainloop, name);
+  pa_operation* operation =
+      pa_context_get_source_info_list(input_context, InputBusCallback, &data);
+  WaitForOperationCompletion(input_mainloop, operation);
+  return data.bus_;
+}
+
+std::string GetOutputCorrespondingTo(const std::string& input_bus,
+                                     pa_threaded_mainloop* input_mainloop,
+                                     pa_context* input_context) {
+  DCHECK(input_mainloop);
+  DCHECK(input_context);
+  AutoPulseLock auto_lock(input_mainloop);
+  OutputBusData data(input_mainloop, input_bus);
+  pa_operation* operation =
+      pa_context_get_sink_info_list(input_context, OutputBusCallback, &data);
+  WaitForOperationCompletion(input_mainloop, operation);
+  return data.name_;
+}
+
 #undef RETURN_ON_FAILURE
 
 }  // namespace pulse