[Cast] Add ListPostprocessors Req/Res to get builtin processors

Bug: b/173015334
Test: run Tongol on device and check available processors.
Change-Id: I4acfe6b02c364a6b2e57d91d76c7bb58f98f47c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533554Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
Commit-Queue: Mingyu Kang <kenkangxgwe@google.com>
Cr-Commit-Position: refs/heads/master@{#827430}

chromecast/media/audio/mixer_service/control_connection.cc

@@ -70,6 +70,17 @@ void ControlConnection::SetVolumeLimit(AudioContentType type,
   }
 }
 
+void ControlConnection::ListPostprocessors(
+    ListPostprocessorsCallback callback) {
+  list_postprocessors_callbacks_.push_back(std::move(callback));
+  if (!socket_) {
+    return;
+  }
+  Generic proto;
+  proto.mutable_list_postprocessors();
+  socket_->SendProto(proto);
+}
+
 void ControlConnection::ConfigurePostprocessor(std::string postprocessor_name,
                                                std::string config) {
   SendPostprocessorMessage(postprocessor_name, config);
@@ -169,6 +180,12 @@ void ControlConnection::OnConnected(std::unique_ptr<MixerSocket> socket) {
     SendPostprocessorMessage(item.first, item.second);
   }
 
+  if (!list_postprocessors_callbacks_.empty()) {
+    Generic message;
+    message.mutable_list_postprocessors();
+    socket_->SendProto(message);
+  }
+
   if (connect_callback_) {
     connect_callback_.Run();
   }
@@ -184,6 +201,18 @@ bool ControlConnection::HandleMetadata(const Generic& message) {
     stream_count_callback_.Run(message.stream_count().primary(),
                                message.stream_count().sfx());
   }
+  if (message.has_postprocessor_list()) {
+    std::vector<std::string> post_processors;
+    for (const auto& post_processor :
+         message.postprocessor_list().postprocessors()) {
+      post_processors.push_back(post_processor);
+    }
+    while (!list_postprocessors_callbacks_.empty()) {
+      std::move(list_postprocessors_callbacks_.front()).Run(post_processors);
+      list_postprocessors_callbacks_.pop_front();
+    }
+  }
+
   return true;
 }
 

chromecast/media/audio/mixer_service/control_connection.h

@@ -5,6 +5,7 @@
 #ifndef CHROMECAST_MEDIA_AUDIO_MIXER_SERVICE_CONTROL_CONNECTION_H_
 #define CHROMECAST_MEDIA_AUDIO_MIXER_SERVICE_CONTROL_CONNECTION_H_
 
+#include <list>
 #include <memory>
 #include <string>
 
@@ -31,6 +32,10 @@ class ControlConnection : public MixerConnection, public MixerSocket::Delegate {
   using StreamCountCallback =
       base::RepeatingCallback<void(int primary_streams, int sfx_streams)>;
 
+  // Callback that handles ListPostProcessors response.
+  using ListPostprocessorsCallback =
+      base::OnceCallback<void(const std::vector<std::string>&)>;
+
   ControlConnection();
   ~ControlConnection() override;
 
@@ -50,6 +55,9 @@ class ControlConnection : public MixerConnection, public MixerSocket::Delegate {
   // Sets the maximum effective volume multiplier for a given content type.
   void SetVolumeLimit(AudioContentType type, float max_volume_multiplier);
 
+  // Returns a set of registered builtin post-processors.
+  void ListPostprocessors(ListPostprocessorsCallback callback);
+
   // Sends arbitrary config data to a specific postprocessor. Config is saved
   // for each unique |name| and will be resent if the mixer disconnects and then
   // reconnects. If the |postprocessor_name| contains a '?', that character and
@@ -96,6 +104,8 @@ class ControlConnection : public MixerConnection, public MixerSocket::Delegate {
   base::flat_map<std::string, std::string> postprocessor_config_;
 
   StreamCountCallback stream_count_callback_;
+  // Uses std::list to trigger callbacks in FIFO order.
+  std::list<ListPostprocessorsCallback> list_postprocessors_callbacks_;
   int num_output_channels_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(ControlConnection);

chromecast/media/audio/mixer_service/mixer_control.cc

@@ -40,6 +40,10 @@ void MixerControl::ConfigurePostprocessor(std::string postprocessor_name,
                 std::move(postprocessor_name), std::move(config));
 }
 
+void MixerControl::ListPostprocessors(ListPostprocessorsCallback callback) {
+  control_.Post(FROM_HERE, &ControlConnection::ListPostprocessors,
+                std::move(callback));
+}
 void MixerControl::ReloadPostprocessors() {
   control_.Post(FROM_HERE, &ControlConnection::ReloadPostprocessors);
 }

chromecast/media/audio/mixer_service/mixer_control.h

@@ -19,6 +19,9 @@ class ControlConnection;
 // Threadsafe process-wide mixer control.
 class MixerControl {
  public:
+  using ListPostprocessorsCallback =
+      base::OnceCallback<void(const std::vector<std::string>&)>;
+
   // Returns the mixer control instance for this process, or nullptr if the
   // mixer is not present on this system.
   static MixerControl* Get();
@@ -27,6 +30,9 @@ class MixerControl {
   void ConfigurePostprocessor(std::string postprocessor_name,
                               std::string config);
 
+  // Sends the request to get the builtin postprocessors and run the callback.
+  void ListPostprocessors(ListPostprocessorsCallback callback);
+
   // Instructs the mixer to reload postprocessors based on the config file.
   void ReloadPostprocessors();
 

chromecast/media/audio/mixer_service/mixer_service.proto

@@ -188,6 +188,13 @@ message SetVolumeLimit {
   optional float max_volume_multiplier = 2;
 }
 
+// Asks the mixer to return a list of registered builtin post processors.
+message ListPostprocessors {}
+
+message PostprocessorList{
+  repeated string postprocessors = 1;
+}
+
 // Sends arbitrary config data to a specific postprocessor.
 message ConfigurePostprocessor {
   optional string name = 1;
@@ -259,4 +266,6 @@ message Generic {
   optional StreamInterruption stream_interruption = 22;
   optional SetAudioClockRate set_audio_clock_rate = 23;
   optional MixerUnderrun mixer_underrun = 24;
+  optional ListPostprocessors list_postprocessors = 25;
+  optional PostprocessorList postprocessor_list = 26;
 }

chromecast/media/cma/backend/mixer/mixer_service_receiver.cc

@@ -15,6 +15,7 @@
 #include "chromecast/media/cma/backend/mixer/loopback_handler.h"
 #include "chromecast/media/cma/backend/mixer/mixer_input_connection.h"
 #include "chromecast/media/cma/backend/mixer/mixer_loopback_connection.h"
+#include "chromecast/media/cma/backend/mixer/post_processor_registry.h"
 #include "chromecast/media/cma/backend/mixer/stream_mixer.h"
 
 namespace chromecast {
@@ -68,6 +69,9 @@ class MixerServiceReceiver::ControlConnection
                             message.set_device_volume().content_type()),
                         message.set_device_volume().volume_multiplier());
     }
+    if (message.has_list_postprocessors()) {
+      OnListPostprocessors();
+    }
     if (message.has_configure_postprocessor()) {
       mixer_->SetPostProcessorConfig(
           message.configure_postprocessor().name(),
@@ -99,6 +103,15 @@ class MixerServiceReceiver::ControlConnection
     return true;
   }
 
+  void OnListPostprocessors() {
+    mixer_service::Generic message;
+    auto* postprocessor_list = message.mutable_postprocessor_list();
+    for (const auto& library_pair : PostProcessorRegistry::Get()->Libraries()) {
+      postprocessor_list->add_postprocessors(library_pair.first);
+    }
+    socket_->SendProto(message);
+  }
+
   void OnConnectionError() override {
     receiver_->RemoveControlConnection(this);
   }

chromecast/media/cma/backend/mixer/post_processor_registry.h

@@ -45,6 +45,11 @@ class PostProcessorRegistry {
                                               const std::string& config,
                                               int channels);
 
+  // Returns a map of registered libraries and their create functions.
+  const base::flat_map<std::string, CreateFunction>& Libraries() const {
+    return creators_;
+  }
+
  private:
   base::flat_map<std::string /* library_name */, CreateFunction> creators_;
 };