Web MIDI API back-end (work-in-progress)

content/browser/renderer_host/media/midi_host.h

Index: content/browser/renderer_host/media/midi_host.h
diff --git a/content/browser/renderer_host/media/midi_host.h b/content/browser/renderer_host/media/midi_host.h
new file mode 100644
index 0000000000000000000000000000000000000000..e46ed539f3804c41c751c1728ea9a25140c80b4e
--- /dev/null
+++ b/content/browser/renderer_host/media/midi_host.h
@@ -0,0 +1,62 @@
+// 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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
+#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/common/content_export.h"
+#include "content/public/browser/browser_message_filter.h"
+#include "content/public/browser/browser_thread.h"
+#include "media/midi/midi_manager.h"
+
+namespace media {
+class MIDIManager;
+}
+
+namespace content {
+
+class CONTENT_EXPORT MIDIHost
+    : public BrowserMessageFilter,
+      public media::MIDIManagerClient {
+ public:
+  // Called from UI thread from the owner of this object.
+  MIDIHost(media::MIDIManager* midi_manager);
+
+  // BrowserMessageFilter implementation.
+  virtual void OnChannelClosing() OVERRIDE;
+  virtual void OnDestruct() const OVERRIDE;
+  virtual bool OnMessageReceived(const IPC::Message& message,
+                                 bool* message_was_ok) OVERRIDE;
+
+  // MIDIManagerClient implementation.
+  virtual void ReceiveMIDIData(
+      int port_index,
+      const uint8* data,
+      size_t length,

[palmer, 2013/06/19 21:39:15]

Does it make sense to subsume |data| and |length| into a const
std::vector<uint8>&, as used in OnSendData, below?

[Chris Rogers, 2013/06/20 17:41:33]

For this layer, I've chosen data and length to avoid another copy into a vector,
since the OS-specific APIs just have a pointer to the bytes directly.

+      double timestamp) OVERRIDE;
+
+  // Request access to MIDI hardware.
+  void OnRequestAccess(int client_id, int access);
+
+  // Data to be sent to a MIDI output port.
+  void OnSendData(int port,
+                  const std::vector<uint8>& data,
+                  double timestamp);
+
+ private:
+  friend class base::DeleteHelper<MIDIHost>;
+  friend class BrowserThread;
+
+  virtual ~MIDIHost();
+
+  media::MIDIManager* const midi_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(MIDIHost);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MIDI_HOST_H_