Web MIDI backend for Windows 10

media/midi/midi_manager_winrt.h

+// 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_MIDI_MIDI_MANAGER_WINRT_H_
+#define MEDIA_MIDI_MIDI_MANAGER_WINRT_H_
+
+#include <memory>
+
+#include "base/strings/string16.h"
+#include "base/threading/thread.h"
+#include "media/midi/midi_manager.h"
+
+namespace base {
+class ThreadChecker;
+}
+
+namespace media {
+namespace midi {
+
+class MidiScheduler;
+
+class MIDI_EXPORT MidiManagerWinrt final : public MidiManager {
+ public:
+  MidiManagerWinrt();
+  ~MidiManagerWinrt() override;
+
+  // MidiManager overrides:
+  void StartInitialization() final;
+  void Finalize() final;
+  void DispatchSendMidiData(MidiManagerClient* client,
+                            uint32_t port_index,
+                            const std::vector<uint8_t>& data,
+                            double timestamp) final;
+
+ private:
+  // Callbacks on the COM thread.
+  void InitializeOnComThread();
+  void FinalizeOnComThread();
+  void SendOnComThread(uint32_t port_index, const std::vector<uint8_t>& data);
+
+  // Callback from MidiPortManager::OnEnumerationComplete on the COM thread.
+  // Calls CompleteInitialization() when both MidiPortManagers are ready.
+  void OnPortManagerReady();
+
+  // Subclasses that access private/protected members of MidiManager.
+  template <typename InterfaceType,
+            typename RuntimeType,
+            typename StaticsInterfaceType,
+            base::char16 const* runtime_class_id>
+  class MidiPortManager;
+  class MidiInPortManager;
+  class MidiOutPortManager;
+
+  // COM-initialized thread for calling WinRT methods.
+  base::Thread com_thread_;
+
+  // Lock to ensure all smart pointers initialized in InitializeOnComThread()
+  // and destroyed in FinalizeOnComThread() will not be accidentally destructed
+  // twice in the destructor.
+  base::Lock lazy_init_member_lock_;
+
+  // Should be instantiated on COM thread.
+  std::unique_ptr<base::ThreadChecker>
+      com_thread_checker_;  // GUARDED_BY(lazy_init_member_lock_)
+
+  // All operations to MidiPortManager should be done on COM thread.
+  std::unique_ptr<MidiInPortManager>
+      port_manager_in_;  // GUARDED_BY(lazy_init_member_lock_)
+  std::unique_ptr<MidiOutPortManager>
+      port_manager_out_;  // GUARDED_BY(lazy_init_member_lock_)
+
+  // |scheduler_| is used by DispatchSendMidiData on Chrome_IOThread, should
+  // acquire lock before use.
+  std::unique_ptr<MidiScheduler>
+      scheduler_;  // GUARDED_BY(lazy_init_member_lock_)
+
+  // Incremented when a MidiPortManager is ready.
+  uint8_t port_manager_ready_count_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(MidiManagerWinrt);
+};
+
+}  // namespace midi
+}  // namespace media
+
+#endif  // MEDIA_MIDI_MIDI_MANAGER_WINRT_H_