[WIP][NotForLand]: Use Mojo for WebMIDI IPC

media/midi/midi_service_impl.h

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// 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.
 
-#ifndef CONTENT_BROWSER_MEDIA_MIDI_HOST_H_
-#define CONTENT_BROWSER_MEDIA_MIDI_HOST_H_
+#ifndef MIDI_SERVICE_IMPL_H_
+#define MIDI_SERVICE_IMPL_H_
 
-#include <vector>
-
-#include "base/gtest_prod_util.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
+#include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/synchronization/lock.h"
-#include "content/common/content_export.h"
-#include "content/public/browser/browser_message_filter.h"
-#include "content/public/browser/browser_thread.h"
+#include "media/base/media_export.h"
 #include "media/midi/midi_manager.h"
+#include "media/midi/midi_message_queue.h"
+#include "media/midi/midi_service.mojom.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace media {
-class MidiManager;
-class MidiMessageQueue;
-}
 
-namespace content {
+class MidiServiceImpl : public MidiService,
+                        public MidiManagerClient {
+ public:
+  MEDIA_EXPORT static void Create(
+      int renderer_process_id,
+      MidiManager* midi_manager,
+      mojo::InterfaceRequest<MidiService> request);
 
-class CONTENT_EXPORT MidiHost
-    : public BrowserMessageFilter,
-      public media::MidiManagerClient {
- public:
-  // Called from UI thread from the owner of this object.
-  MidiHost(int renderer_process_id, media::MidiManager* midi_manager);
+ private:
+  typedef mojo::Callback<void(MidiResultMojo)> StartSessionCallback;
+  typedef mojo::Callback<void(uint32_t)> SendDataCallback;
 
-  // BrowserMessageFilter implementation.
-  void OnDestruct() const override;
-  bool OnMessageReceived(const IPC::Message& message) override;
+  explicit MidiServiceImpl(
+      int renderer_process_id,
+      MidiManager* midi_manager,
+      mojo::InterfaceRequest<MidiService> request);
+  ~MidiServiceImpl() override;
+
+  // Returns true if |data| fulfills the requirements of MidiOutput.send API
+  // defined in the WebMIDI spec.
+  // - |data| must be any number of complete MIDI messages (data abbreviation
+  //    called "running status" is disallowed).
+  // - 1-byte MIDI realtime messages can be placed at any position of |data|.
+  static bool IsValidWebMIDIData(const std::vector<uint8_t>& data);
+
+  // MidiService methods.
+  void StartSession(
+      MidiServiceClientPtr client,
+      const StartSessionCallback& callback) override;
+  void EndSession() override;
+  void SendData(uint32_t port,
+                mojo::Array<uint8_t> data,
+                double timestamp) override;
 
   // MidiManagerClient implementation.
   void CompleteStartSession(media::MidiResult result) override;
   void AddInputPort(const media::MidiPortInfo& info) override;
   void AddOutputPort(const media::MidiPortInfo& info) override;
   void ReceiveMidiData(uint32 port,
                        const uint8* data,
                        size_t length,
                        double timestamp) override;
   void AccumulateMidiBytesSent(size_t n) override;
 
-  // Start session to access MIDI hardware.
-  void OnStartSession();
-
-  // Data to be sent to a MIDI output port.
-  void OnSendData(uint32 port,
-                  const std::vector<uint8>& data,
-                  double timestamp);
-
-  void OnEndSession();
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(MidiHostTest, IsValidWebMIDIData);
-  friend class base::DeleteHelper<MidiHost>;
-  friend class BrowserThread;
-
-  ~MidiHost() override;
-
-  // Returns true if |data| fulfills the requirements of MidiOutput.send API
-  // defined in the WebMIDI spec.
-  // - |data| must be any number of complete MIDI messages (data abbreviation
-  //    called "running status" is disallowed).
-  // - 1-byte MIDI realtime messages can be placed at any position of |data|.
-  static bool IsValidWebMIDIData(const std::vector<uint8>& data);
+  mojo::StrongBinding<MidiService> binding_;
+  MidiServiceClientPtr client_;
+  StartSessionCallback start_session_callback_;
 
   int renderer_process_id_;
 
   // Represents if the renderer has a permission to send/receive MIDI SysEX
   // messages.
-  bool has_sys_ex_permission_;
+  bool has_sys_ex_permission_ = false;
 
   // Represents if a session is requested to start.
-  bool is_session_requested_;
+  bool is_session_requested_ = false;
 
   // |midi_manager_| talks to the platform-specific MIDI APIs.
   // It can be NULL if the platform (or our current implementation)
   // does not support MIDI.  If not supported then a call to
   // OnRequestAccess() will always refuse access and a call to
   // OnSendData() will do nothing.
-  media::MidiManager* const midi_manager_;
+  MidiManager* const midi_manager_ = nullptr;
 
   // Buffers where data sent from each MIDI input port is stored.
-  ScopedVector<media::MidiMessageQueue> received_messages_queues_;
+  ScopedVector<MidiMessageQueue> received_messages_queues_;
 
   // Protects access to |received_messages_queues_|;
   base::Lock messages_queues_lock_;
 
   // The number of bytes sent to the platform-specific MIDI sending
   // system, but not yet completed.
-  size_t sent_bytes_in_flight_;
+  size_t sent_bytes_in_flight_ = 0;
 
   // The number of bytes successfully sent since the last time
   // we've acknowledged back to the renderer.
-  size_t bytes_sent_since_last_acknowledgement_;
+  size_t bytes_sent_since_last_acknowledgement_ = 0;
 
   // Protects access to |sent_bytes_in_flight_|.
   base::Lock in_flight_lock_;
 
-  DISALLOW_COPY_AND_ASSIGN(MidiHost);
+  DISALLOW_COPY_AND_ASSIGN(MidiServiceImpl);
 };
 
-}  // namespace content
+}  // namespace media
 
-#endif  // CONTENT_BROWSER_MEDIA_MIDI_HOST_H_
+#endif  // MIDI_SERVICE_IMPL_H_