Implement Web MIDI API back-end

This involves browser-side support and IPC for sending and receiving
MIDI messages.  Initially support for OSX is included.

BUG=163795
R=palmer@chromium.org, piman@chromium.org, scherkus@chromium.org

Review URL: https://codereview.chromium.org/16025005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207983 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 67 insertions, 0 deletions

diff --git a/media/midi/midi_manager.cc b/media/midi/midi_manager.cc
new file mode 100644
index 0000000..f991865
--- /dev/null
+++ b/media/midi/midi_manager.cc
@@ -0,0 +1,67 @@
+// 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.
+
+#include "media/midi/midi_manager.h"
+
+namespace media {
+
+#if !defined(OS_MACOSX)
+// TODO(crogers): implement MIDIManager for other platforms.
+MIDIManager* MIDIManager::Create() {
+  return NULL;
+}
+#endif
+
+MIDIManager::MIDIManager()
+    : initialized_(false) {
+}
+
+MIDIManager::~MIDIManager() {}
+
+bool MIDIManager::RequestAccess(MIDIManagerClient* client, int access) {
+  // TODO(crogers): determine if user prompt is necessary here.
+  // For now, simply don't allow sysex.
+  if (access != kNoSystemExclusive)
+    return false;
+
+  // Lazily initialize the MIDI back-end.
+  if (!initialized_)
+    initialized_ = Initialize();
+
+  if (initialized_) {
+    base::AutoLock auto_lock(clients_lock_);
+    clients_.insert(client);
+  }
+
+  return initialized_;
+}
+
+void MIDIManager::ReleaseAccess(MIDIManagerClient* client) {
+  base::AutoLock auto_lock(clients_lock_);
+  ClientList::iterator i = clients_.find(client);
+  if (i != clients_.end())
+    clients_.erase(i);
+}
+
+void MIDIManager::AddInputPort(const MIDIPortInfo& info) {
+  input_ports_.push_back(info);
+}
+
+void MIDIManager::AddOutputPort(const MIDIPortInfo& info) {
+  output_ports_.push_back(info);
+}
+
+void MIDIManager::ReceiveMIDIData(
+    int port_index,
+    const uint8* data,
+    size_t length,
+    double timestamp) {
+  base::AutoLock auto_lock(clients_lock_);
+
+  // TODO(crogers): Filter out sysex.
+  for (ClientList::iterator i = clients_.begin(); i != clients_.end(); ++i)
+    (*i)->ReceiveMIDIData(port_index, data, length, timestamp);
+};
+
+}  // namespace media