Re-land 16025005 with fix for statics perf issue

content/renderer/media/midi_message_filter.cc

Index: content/renderer/media/midi_message_filter.cc
diff --git a/content/renderer/media/midi_message_filter.cc b/content/renderer/media/midi_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1abb537a9d9b28070e02b635c3d3a50c55004e26
--- /dev/null
+++ b/content/renderer/media/midi_message_filter.cc
@@ -0,0 +1,199 @@
+// 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 "content/renderer/media/midi_message_filter.h"
+
+#include "base/bind.h"
+#include "base/debug/trace_event.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "base/strings/utf_string_conversions.h"
+#include "content/common/media/midi_messages.h"
+#include "content/renderer/render_thread_impl.h"
+#include "ipc/ipc_logging.h"
+
+using media::MIDIPortInfoList;
+using base::AutoLock;
+
+namespace content {
+
+MIDIMessageFilter::MIDIMessageFilter(
+    const scoped_refptr<base::MessageLoopProxy>& io_message_loop)
+    : channel_(NULL),
+      io_message_loop_(io_message_loop),
+      next_available_id_(0) {
+}
+
+MIDIMessageFilter::~MIDIMessageFilter() {}
+
+void MIDIMessageFilter::Send(IPC::Message* message) {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+  if (!channel_) {
+    delete message;
+  } else {
+    channel_->Send(message);
+  }
+}
+
+bool MIDIMessageFilter::OnMessageReceived(const IPC::Message& message) {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(MIDIMessageFilter, message)
+    IPC_MESSAGE_HANDLER(MIDIMsg_AccessApproved, OnAccessApproved)
+    IPC_MESSAGE_HANDLER(MIDIMsg_DataReceived, OnDataReceived)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void MIDIMessageFilter::OnFilterAdded(IPC::Channel* channel) {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+  channel_ = channel;
+}
+
+void MIDIMessageFilter::OnFilterRemoved() {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+
+  // Once removed, a filter will not be used again.  At this time all
+  // delegates must be notified so they release their reference.
+  OnChannelClosing();
+}
+
+void MIDIMessageFilter::OnChannelClosing() {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+  channel_ = NULL;
+}
+
+void MIDIMessageFilter::RequestAccess(
+    WebKit::WebMIDIAccessorClient* client, int access) {
+  // Generate and keep track of a "client id" which is sent to the browser
+  // to ask permission to talk to MIDI hardware.
+  // This id is handed back when we receive the answer in OnAccessApproved().
+  if (clients_.find(client) == clients_.end()) {
+    int client_id = next_available_id_++;
+    clients_[client] = client_id;
+
+    io_message_loop_->PostTask(FROM_HERE,
+        base::Bind(&MIDIMessageFilter::RequestAccessOnIOThread, this,
+                   client_id, access));
+  }
+}
+
+void MIDIMessageFilter::RequestAccessOnIOThread(int client_id, int access) {
+  Send(new MIDIHostMsg_RequestAccess(client_id, access));
+}
+
+void MIDIMessageFilter::RemoveClient(WebKit::WebMIDIAccessorClient* client) {
+  ClientsMap::iterator i = clients_.find(client);
+  if (i != clients_.end())
+    clients_.erase(i);
+}
+
+// Received from browser.
+
+void MIDIMessageFilter::OnAccessApproved(
+    int client_id,
+    int access,
+    bool success,
+    MIDIPortInfoList inputs,
+    MIDIPortInfoList outputs) {
+  // Handle on the main JS thread.
+  ChildThread::current()->message_loop()->PostTask(FROM_HERE,
+      base::Bind(&MIDIMessageFilter::HandleAccessApproved, this,
+                 client_id, access, success, inputs, outputs));
+}
+
+void MIDIMessageFilter::HandleAccessApproved(
+    int client_id,
+    int access,
+    bool success,
+    MIDIPortInfoList inputs,
+    MIDIPortInfoList outputs) {
+  WebKit::WebMIDIAccessorClient* client = GetClientFromId(client_id);
+  if (!client)
+    return;
+
+  if (success) {
+    // Add the client's input and output ports.
+    for (size_t i = 0; i < inputs.size(); ++i) {
+      client->didAddInputPort(
+          UTF8ToUTF16(inputs[i].id),
+          UTF8ToUTF16(inputs[i].manufacturer),
+          UTF8ToUTF16(inputs[i].name),
+          UTF8ToUTF16(inputs[i].version));
+    }
+
+    for (size_t i = 0; i < outputs.size(); ++i) {
+      client->didAddOutputPort(
+          UTF8ToUTF16(outputs[i].id),
+          UTF8ToUTF16(outputs[i].manufacturer),
+          UTF8ToUTF16(outputs[i].name),
+          UTF8ToUTF16(outputs[i].version));
+    }
+  }
+
+  if (success)
+    client->didAllowAccess();
+  else
+    client->didBlockAccess();
+}
+
+WebKit::WebMIDIAccessorClient*
+MIDIMessageFilter::GetClientFromId(int client_id) {
+  // Iterating like this seems inefficient, but in practice there generally
+  // will be very few clients (usually one).  Additionally, this lookup
+  // usually happens one time during page load. So the performance hit is
+  // negligible.
+  for (ClientsMap::iterator i = clients_.begin(); i != clients_.end(); ++i) {
+    if ((*i).second == client_id)
+      return (*i).first;
+  }
+  return NULL;
+}
+
+void MIDIMessageFilter::OnDataReceived(int port,
+                                       const std::vector<uint8>& data,
+                                       double timestamp) {
+  TRACE_EVENT0("midi", "MIDIMessageFilter::OnDataReceived");
+
+  ChildThread::current()->message_loop()->PostTask(FROM_HERE,
+      base::Bind(&MIDIMessageFilter::HandleDataReceived, this,
+                 port, data, timestamp));
+}
+
+void MIDIMessageFilter::HandleDataReceived(int port,
+                                           const std::vector<uint8>& data,
+                                           double timestamp) {
+  TRACE_EVENT0("midi", "MIDIMessageFilter::HandleDataReceived");
+
+#if defined(OS_ANDROID)
+  // TODO(crogers): figure out why data() method does not compile on Android.
+  NOTIMPLEMENTED();
+#else
+  for (ClientsMap::iterator i = clients_.begin(); i != clients_.end(); ++i)
+    (*i).first->didReceiveMIDIData(port, data.data(), data.size(), timestamp);
+#endif
+}
+
+void MIDIMessageFilter::SendMIDIData(int port,
+                                     const uint8* data,
+                                     size_t length,
+                                     double timestamp) {
+  // TODO(crogers): we need more work to check the amount of data sent,
+  // throttle if necessary, and filter out the SYSEX messages if not
+  // approved. For now, we will not implement the sending of MIDI data.
+  NOTIMPLEMENTED();
+  // std::vector<uint8> v(data, data + length);
+  // io_message_loop_->PostTask(FROM_HERE,
+  //     base::Bind(&MIDIMessageFilter::SendMIDIDataOnIOThread, this,
+  //                port, v, timestamp));
+}
+
+void MIDIMessageFilter::SendMIDIDataOnIOThread(int port,
+                                               const std::vector<uint8>& data,
+                                               double timestamp) {
+  // Send to the browser.
+  Send(new MIDIHostMsg_SendData(port, data, timestamp));
+}
+
+}  // namespace content