WIP - Add EME

media/remoting/remoting_source_impl.h

Index: media/remoting/remoting_source_impl.h
diff --git a/media/remoting/remoting_source_impl.h b/media/remoting/remoting_source_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..e2ec5e82443299932f2d279ef895a5f88f110830
--- /dev/null
+++ b/media/remoting/remoting_source_impl.h
@@ -0,0 +1,118 @@
+// Copyright 2016 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.
+
+#ifndef MEDIA_REMOTING_REMOTING_SOURCE_IMPL_H_
+#define MEDIA_REMOTING_REMOTING_SOURCE_IMPL_H_
+
+#include <set>
+
+#include "media/mojo/interfaces/remoting.mojom.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace base {

[miu, 2016/10/25 04:21:27]

Please remove this forward declaration and instead #include
"base/threading/thread_checker.h" The RemotingSourceImpl class declaration below
is only compiling because one of the #includes above is pulling-in the full
declaration of ThreadChecker for you. ;)

[xjz, 2016/10/26 22:00:27]

Done.

+class ThreadChecker;
+}
+
+namespace media {
+
+enum RemotingSessionState {
+  // Remoting sink is not available. Can't start remoting.
+  SESSION_UNAVAILABLE,
+  // Remoting sink is available, Can start remoting.
+  SESSION_CAN_START,
+  // Starting a remoting session.
+  SESSION_STARTING,
+  // Remoting session is successively started.
+  SESSION_STARTED,
+  // Stopping the session.
+  SESSION_STOPPING,
+  // Remoting session is permanently stopped. This state indicates that the
+  // video stack cannot continue operation. For example, if a remoting session
+  // involving CDM content was stopped, there is no way to continue playback
+  // because the CDM is required but is no longer available.
+  SESSION_PERMANENTLY_STOPPED,
+};
+
+// Maintains a single remoting session for multiple clients. The session will
+// start remoting when receiving the first request. Once remoting is started,
+// it will be stopped when any of the following happens:
+// 1) Receives the request from any client to stop remoting.
+// 2) Remote sink is gone.
+// 3) Any client requests to permanently terminated the session.

[miu, 2016/10/25 04:21:27]

s/terminated/terminate/

[xjz, 2016/10/26 22:00:27]

Done.

+// 4) All clients are destroyed.
+class RemotingSourceImpl final

[miu, 2016/10/25 04:21:27]

Another helpful thing to add to the class-level comment:

  // This class is ref-counted because, in some cases, an instance will have
shared ownership between RemotingRendererController and RemotingCdmController.

[xjz, 2016/10/26 22:00:27]

Done.

+    : public mojom::RemotingSource,
+      public base::RefCountedThreadSafe<RemotingSourceImpl> {
+ public:
+  RemotingSourceImpl(mojom::RemotingSourceRequest source_request,
+                     mojom::RemoterPtr remoter);
+
+  class Client {

[miu, 2016/10/25 04:21:27]

style nit: Type declarations have to go at the top (just after "public:").

[xjz, 2016/10/26 22:00:27]

Done.

+   public:
+    // Get notified whether the remoting session is successively started.
+    virtual void OnStarted(bool success) = 0;
+    // Get notified when session state changes.
+    virtual void OnSessionStateChanged() = 0;
+  };
+
+  // Get the current session state.
+  RemotingSessionState state() const {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    return state_;
+  }
+
+  // RemotingSource implementations.
+  void OnSinkAvailable() override;
+  void OnSinkGone() override;
+  void OnStarted() override;
+  void OnStartFailed(mojom::RemotingStartFailReason reason) override;
+  void OnMessageFromSink(const std::vector<uint8_t>& message) override;
+  void OnStopped(mojom::RemotingStopReason reason) override;
+
+  // Requests to start remoting. Will try start a remoting session if not
+  // started yet. |client| will get informed whether the session is
+  // successifully started throught OnStarted().
+  void StartRemoting(Client* client);
+
+  // Requests to stop the current remoting session if started. When the session
+  // is stopping, all clients will get notified.
+  void StopRemoting(Client* client);
+
+  // Permanently terminates the current remoting session.
+  void ShutDown();
+
+  // Add/remove a client to/from |clients_|.
+  // Remoting session will be stopped if all clients are gone.
+  void AddClient(Client* client);
+  void RemoveClient(Client* client);
+
+ private:
+  friend class base::RefCountedThreadSafe<RemotingSourceImpl>;
+  ~RemotingSourceImpl() override;
+
+  // Updates the current session state and notifies all the clients if state
+  // changes.
+  void UpdateAndNotifyState(RemotingSessionState state);
+
+  mojo::Binding<mojom::RemotingSource> binding_;
+  mojom::RemoterPtr remoter_;

[miu, 2016/10/25 04:21:27]

const please

[xjz, 2016/10/26 22:00:27]

Done.

+
+  // The current state.
+  RemotingSessionState state_ = RemotingSessionState::SESSION_UNAVAILABLE;
+
+  // This is set to true when OnSinkAvailable() is called, and is reset when
+  // sink is gone.
+  bool is_sink_available_ = false;

[miu, 2016/10/25 04:21:27]

You can remove this boolean. See comments in .cc file. After making changes in
the .cc file, I think you'll notice that |is_sink_available_| is no longer used.

[xjz, 2016/10/26 22:00:27]

Done.

+
+  // Clients are added/removed to/from this list by calling Add/RemoveClient().
+  std::set<Client*> clients_;

[miu, 2016/10/25 04:21:27]

Use std::vector<Client*> instead (saves memory and CPU runtime overhead because
we expect only one or two clients).

[xjz, 2016/10/26 22:00:27]

Done.

+
+  // This is used to check all the methods are called on the current thread in
+  // debug builds.
+  base::ThreadChecker thread_checker_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_REMOTING_REMOTING_SOURCE_IMPL_H_