Web MIDI: add dynamic MidiManager instantiation support for Linux

media/midi/midi_manager.h

 // Copyright (c) 2013 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_MIDI_MIDI_MANAGER_H_
 #define MEDIA_MIDI_MIDI_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <set>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
 #include "media/midi/midi_export.h"
 #include "media/midi/midi_port_info.h"
 #include "media/midi/midi_service.mojom.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace midi {
 
+class MidiService;
+
 // A MidiManagerClient registers with the MidiManager to receive MIDI data.
 // See MidiManager::RequestAccess() and MidiManager::ReleaseAccess()
 // for details.
 // TODO(toyoshim): Consider to have a MidiServiceClient interface.
 class MIDI_EXPORT MidiManagerClient {
  public:
   virtual ~MidiManagerClient() {}
 
   // AddInputPort() and AddOutputPort() are called before CompleteStartSession()
   // is called to notify existing MIDI ports, and also called after that to
@@ skipping 28 matching lines @@
   // This happens as a result of the client having previously called
   // MidiManager::DispatchSendMidiData().
   virtual void AccumulateMidiBytesSent(size_t n) = 0;
 
   // Detach() is called when MidiManager is going to shutdown immediately.
   // Client should not touch MidiManager instance after Detach() is called.
   virtual void Detach() = 0;
 };
 
 // Manages access to all MIDI hardware.
+// *** Note ***: If dynamic instantiation feature is enabled, all MidiManager
+// methods will be called on Chrome_IOThread. See comments on Shutdown() too.
 class MIDI_EXPORT MidiManager {
  public:
   static const size_t kMaxPendingClientCount = 128;
 
-  MidiManager();
+  MidiManager(MidiService* service);

[yhirano, 2017/02/08 10:04:36]

+explicit

[Takashi Toyoshima, 2017/02/08 11:08:55]

Done.

   virtual ~MidiManager();
 
   // The constructor and the destructor will be called on the CrBrowserMain
   // thread.
-  static MidiManager* Create();
+  static MidiManager* Create(MidiService* service);
 
   // Called on the CrBrowserMain thread to notify the Chrome_IOThread will stop
   // and the instance will be destructed on the CrBrowserMain thread soon.
+  // *** Note ***: If dynamic instantiation feature is enabled, MidiService call

[yhirano, 2017/02/08 10:04:36]

call"s"

[Takashi Toyoshima, 2017/02/08 11:08:55]

Done.

+  // this on Chrome_IOThread and ShutdownOnSessionThread() will be called
+  // synchronously so that MidiService can destruct MidiManager synchronously.
   void Shutdown();
 
   // A client calls StartSession() to receive and send MIDI data.
   // If the session is ready to start, the MIDI system is lazily initialized
   // and the client is registered to receive MIDI data.
   // CompleteStartSession() is called with mojom::Result::OK if the session is
   // started. Otherwise CompleteStartSession() is called with a proper
   // mojom::Result code.
   // StartSession() and EndSession() can be called on the Chrome_IOThread.
   // CompleteStartSession() will be invoked on the same Chrome_IOThread.
@@ skipping 68 matching lines @@
                     (time - base::TimeTicks()).InSecondsF());
   }
 
   size_t clients_size_for_testing() const { return clients_.size(); }
   size_t pending_clients_size_for_testing() const {
     return pending_clients_.size();
   }
 
   const MidiPortInfoList& input_ports() const { return input_ports_; }
   const MidiPortInfoList& output_ports() const { return output_ports_; }
+  MidiService* service() { return service_; }
 
  private:
   enum class InitializationState {
     NOT_STARTED,
     STARTED,
     COMPLETED,
   };
 
   void CompleteInitializationInternal(mojom::Result result);
   void AddInitialPorts(MidiManagerClient* client);
@@ skipping 22 matching lines @@
 
   // Keeps all MidiPortInfo.
   MidiPortInfoList input_ports_;
   MidiPortInfoList output_ports_;
 
   // Protects access to |clients_|, |pending_clients_|,
   // |session_thread_runner_|, |initialization_state_|, |finalize_|, |result_|,
   // |input_ports_| and |output_ports_|.
   base::Lock lock_;
 
+  // MidiService outlives MidiManager.
+  MidiService* const service_;
+
   DISALLOW_COPY_AND_ASSIGN(MidiManager);
 };
 
 }  // namespace midi
 
 #endif  // MEDIA_MIDI_MIDI_MANAGER_H_