media: Quit MojoMediaApplication when no service is bound.

media/mojo/services/mojo_media_application.cc

 // Copyright 2014 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/mojo/services/mojo_media_application.h"
 
 #include "base/logging.h"
+#include "base/thread_task_runner_handle.h"
 #include "media/mojo/services/mojo_cdm_service.h"
 #include "media/mojo/services/mojo_renderer_service.h"
 #include "mojo/application/public/cpp/application_connection.h"
 #include "mojo/application/public/cpp/application_impl.h"
 
 namespace media {
 
 const char kMojoMediaAppUrl[] = "mojo:media";
+const int kIdleTimeoutInSeconds = 30;
 
 // static
 GURL MojoMediaApplication::AppUrl() {
   return GURL(kMojoMediaAppUrl);
 }
 
 // static
 scoped_ptr<mojo::ApplicationDelegate> MojoMediaApplication::CreateApp() {
   return scoped_ptr<mojo::ApplicationDelegate>(new MojoMediaApplication());
 }
 
 MojoMediaApplication::MojoMediaApplication() {
 }
 
 MojoMediaApplication::~MojoMediaApplication() {
 }
 
 void MojoMediaApplication::Initialize(mojo::ApplicationImpl* app) {
+  app_impl_ = app;

[sky, 2015/06/24 03:03:31]

Add to member initializers and set to null.

[xhwang, 2015/06/26 16:30:07]

Added Class Member Initializers.

+
+  // Enable logging.
   logging::LoggingSettings settings;
   settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;
   logging::InitLogging(settings);
   // Display process ID, thread ID and timestamp in logs.
   logging::SetLogItems(true, true, true, false);
+
+  StartIdleTimer();
 }
 
 bool MojoMediaApplication::ConfigureIncomingConnection(
     mojo::ApplicationConnection* connection) {
   connection->AddService<mojo::ContentDecryptionModule>(this);
   connection->AddService<mojo::MediaRenderer>(this);
   return true;
 }
 
 void MojoMediaApplication::Create(
     mojo::ApplicationConnection* connection,
     mojo::InterfaceRequest<mojo::ContentDecryptionModule> request) {
   // The created object is owned by the pipe.
-  new MojoCdmService(&cdm_service_context_, request.Pass());
+  MojoCdmService* mojo_cdm_service =
+      new MojoCdmService(&cdm_service_context_, request.Pass());
+
+  // Passing unretained |this| is safe here because the app is guaranteed to
+  // outlive all services.
+  mojo_cdm_service->set_connection_error_handler(base::Bind(
+      &MojoMediaApplication::OnConnectionError, base::Unretained(this)));

[sky, 2015/06/24 03:03:31]

I'm not familiar with this code. Who owns mojo_cmd_service? And who owns
MojoMedaiApplication?

[xhwang, 2015/06/25 18:09:52]

mojo_cmd_service is owned by the pipe since it uses the StrongBinding.

MojoMedaiApplication is owned by the ApplicationRunner [1], which has the same
lifetime as the RunnerThread [2]

[1]
https://code.google.com/p/chromium/codesearch#chromium/src/mojo/application/p...
[2]
https://code.google.com/p/chromium/codesearch#chromium/src/mojo/shell/static_...

+
+  active_service_count_++;
+  idle_timeout_callback_.Cancel();
 }
 
 void MojoMediaApplication::Create(
     mojo::ApplicationConnection* connection,
     mojo::InterfaceRequest<mojo::MediaRenderer> request) {
   // The created object is owned by the pipe.
-  new MojoRendererService(request.Pass());
+  MojoRendererService* mojo_renderer_service =
+      new MojoRendererService(request.Pass());
+
+  // Passing unretained |this| is safe here because the app is guaranteed to
+  // outlive all services.
+  mojo_renderer_service->set_connection_error_handler(base::Bind(
+      &MojoMediaApplication::OnConnectionError, base::Unretained(this)));
+
+  active_service_count_++;
+  idle_timeout_callback_.Cancel();
+}
+
+void MojoMediaApplication::Quit() {
+  app_impl_ = nullptr;
+}
+
+void MojoMediaApplication::StartIdleTimer() {
+  // Passing unretained |app_impl_| is safe here because |app_impl_| is
+  // guaranteed to outlive |this|, and the callback is canceled if |this| is
+  // destroyed.
+  idle_timeout_callback_.Reset(base::Bind(&mojo::ApplicationImpl::Terminate,
+                                          base::Unretained(app_impl_)));
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE, idle_timeout_callback_.callback(),
+      base::TimeDelta::FromSeconds(kIdleTimeoutInSeconds));
+}
+
+void MojoMediaApplication::OnConnectionError() {
+  DCHECK_GT(active_service_count_, 0u);
+  active_service_count_--;
+  if (active_service_count_ == 0) {
+    // If the last service connection has been dropped, kick off an idle timeout
+    // to shut ourselves down.
+    StartIdleTimer();
+  }
 }
 
 }  // namespace media