[WIP][NotForLand]: Use Mojo for WebMIDI IPC

media/midi/midi_service_impl.cc

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Copyright 2014 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/browser/media/midi_host.h"
+#include "media/midi/midi_service_impl.h"
 
-#include "base/bind.h"
-#include "base/bind_helpers.h"
 #include "base/debug/trace_event.h"
-#include "base/process/process.h"
-#include "content/browser/browser_main_loop.h"
+#include "base/logging.h"
 #include "content/browser/child_process_security_policy_impl.h"
-#include "content/browser/media/media_internals.h"
-#include "content/common/media/midi_messages.h"
-#include "content/public/browser/content_browser_client.h"
-#include "content/public/browser/media_observer.h"
-#include "content/public/browser/user_metrics.h"
-#include "media/midi/midi_manager.h"
-#include "media/midi/midi_message_queue.h"
 #include "media/midi/midi_message_util.h"
 
-using media::MidiManager;
-using media::MidiPortInfoList;
-
-namespace content {
+namespace media {
 namespace {
 
 // The total number of bytes which we're allowed to send to the OS
 // before knowing that they have been successfully sent.
 const size_t kMaxInFlightBytes = 10 * 1024 * 1024;  // 10 MB.
 
 // We keep track of the number of bytes successfully sent to
 // the hardware.  Every once in a while we report back to the renderer
 // the number of bytes sent since the last report. This threshold determines
 // how many bytes will be sent before reporting back to the renderer.
 const size_t kAcknowledgementThresholdBytes = 1024 * 1024;  // 1 MB.
 
 bool IsDataByte(uint8 data) {
   return (data & 0x80) == 0;
 }
 
 bool IsSystemRealTimeMessage(uint8 data) {
   return 0xf8 <= data && data <= 0xff;
 }
 
 }  // namespace
 
-using media::kSysExByte;
-using media::kEndOfSysExByte;
+// static
+void MidiServiceImpl::Create(
+    int renderer_process_id,
+    MidiManager* midi_manager,
+    mojo::InterfaceRequest<MidiService> request) {
+  new MidiServiceImpl(renderer_process_id, midi_manager, request.Pass());
+}
 
-MidiHost::MidiHost(int renderer_process_id, media::MidiManager* midi_manager)
-    : BrowserMessageFilter(MidiMsgStart),
+MidiServiceImpl::MidiServiceImpl(
+    int renderer_process_id,
+    MidiManager* midi_manager,
+    mojo::InterfaceRequest<MidiService> request)
+    : binding_(this, request.Pass()),
       renderer_process_id_(renderer_process_id),
-      has_sys_ex_permission_(false),
-      is_session_requested_(false),
-      midi_manager_(midi_manager),
-      sent_bytes_in_flight_(0),
-      bytes_sent_since_last_acknowledgement_(0) {
+      midi_manager_(midi_manager) {
   CHECK(midi_manager_);
 }
 
-MidiHost::~MidiHost() {
-  // Close an open session, or abort opening a session.
+MidiServiceImpl::~MidiServiceImpl() {
   if (is_session_requested_)
     midi_manager_->EndSession(this);
 }
 
-void MidiHost::OnDestruct() const {
-  BrowserThread::DeleteOnIOThread::Destruct(this);
-}
-
-// IPC Messages handler
-bool MidiHost::OnMessageReceived(const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(MidiHost, message)
-    IPC_MESSAGE_HANDLER(MidiHostMsg_StartSession, OnStartSession)
-    IPC_MESSAGE_HANDLER(MidiHostMsg_SendData, OnSendData)
-    IPC_MESSAGE_HANDLER(MidiHostMsg_EndSession, OnEndSession)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-
-  return handled;
-}
-
-void MidiHost::OnStartSession() {
+void MidiServiceImpl::StartSession(
+    MidiServiceClientPtr client, const StartSessionCallback& callback) {
+  client_ = client.Pass();
+  start_session_callback_ = callback;
   is_session_requested_ = true;
   midi_manager_->StartSession(this);
 }
 
-void MidiHost::OnSendData(uint32 port,
-                          const std::vector<uint8>& data,
-                          double timestamp) {
-  if (data.empty())
+void MidiServiceImpl::EndSession() {
+  is_session_requested_ = false;
+  midi_manager_->EndSession(this);
+}
+
+void MidiServiceImpl::SendData(uint32_t port,
+                                mojo::Array<uint8_t> data,
+                                double timestamp) {
+  if (data.size() == 0)
     return;
 
+  const std::vector<uint8_t>& raw_data = data.storage();
   // Blink running in a renderer checks permission to raise a SecurityError
   // in JavaScript. The actual permission check for security purposes
   // happens here in the browser process.
   if (!has_sys_ex_permission_ &&
-      std::find(data.begin(), data.end(), kSysExByte) != data.end()) {
-    RecordAction(base::UserMetricsAction("BadMessageTerminate_MIDI"));
-    BadMessageReceived();
+      std::find(raw_data.begin(), raw_data.end(), kSysExByte)
+      != raw_data.end()) {
+    // TODO(bashi): We no longer use Chromium IPC. What should we do when the
+    // check fails?
     return;
   }
 
   if (!IsValidWebMIDIData(data))
     return;
 
   {
     base::AutoLock auto_lock(in_flight_lock_);
     // Sanity check that we won't send too much data.
     // TODO(yukawa): Consider to send an error event back to the renderer
     // after some future discussion in W3C.
     if (data.size() + sent_bytes_in_flight_ > kMaxInFlightBytes)
       return;
     sent_bytes_in_flight_ += data.size();
   }
-  midi_manager_->DispatchSendMidiData(this, port, data, timestamp);
+  midi_manager_->DispatchSendMidiData(this, port, raw_data, timestamp);
 }
 
-void MidiHost::OnEndSession() {
-  is_session_requested_ = false;
-  midi_manager_->EndSession(this);
-}
-
-void MidiHost::CompleteStartSession(media::MidiResult result) {
+void MidiServiceImpl::CompleteStartSession(media::MidiResult result) {
   DCHECK(is_session_requested_);
   if (result == media::MIDI_OK) {
     // ChildSecurityPolicy is set just before OnStartSession by
     // MidiDispatcherHost. So we can safely cache the policy.
-    has_sys_ex_permission_ = ChildProcessSecurityPolicyImpl::GetInstance()->
+    has_sys_ex_permission_ =
+        content::ChildProcessSecurityPolicyImpl::GetInstance()->
         CanSendMidiSysExMessage(renderer_process_id_);
   }
-  Send(new MidiMsg_SessionStarted(result));
+  start_session_callback_.Run(static_cast<MidiResultMojo>(result));
 }
 
-void MidiHost::AddInputPort(const media::MidiPortInfo& info) {
+void MidiServiceImpl::AddInputPort(const media::MidiPortInfo& info) {
   base::AutoLock auto_lock(messages_queues_lock_);
   // MidiMessageQueue is created later in ReceiveMidiData().
   received_messages_queues_.push_back(nullptr);
-  Send(new MidiMsg_AddInputPort(info));
+  MidiPortInfoMojoPtr info_mojo(MidiPortInfoMojo::New());
+  info_mojo->id = info.id;
+  info_mojo->manufacturer = info.manufacturer;
+  info_mojo->name = info.name;
+  info_mojo->version = info.version;
+  client_->AddInputPort(info_mojo.Pass());
 }
 
-void MidiHost::AddOutputPort(const media::MidiPortInfo& info) {
-  Send(new MidiMsg_AddOutputPort(info));
+void MidiServiceImpl::AddOutputPort(const media::MidiPortInfo& info) {
+  MidiPortInfoMojoPtr info_mojo(MidiPortInfoMojo::New());
+  info_mojo->id = info.id;
+  info_mojo->manufacturer = info.manufacturer;
+  info_mojo->name = info.name;
+  info_mojo->version = info.version;
+  client_->AddOutputPort(info_mojo.Pass());
 }
 
-void MidiHost::ReceiveMidiData(
+void MidiServiceImpl::ReceiveMidiData(
     uint32 port,
     const uint8* data,
     size_t length,
     double timestamp) {
   TRACE_EVENT0("midi", "MidiHost::ReceiveMidiData");
 
   base::AutoLock auto_lock(messages_queues_lock_);
   if (received_messages_queues_.size() <= port)
     return;
 
   // Lazy initialization
   if (received_messages_queues_[port] == nullptr)
     received_messages_queues_[port] = new media::MidiMessageQueue(true);
 
   received_messages_queues_[port]->Add(data, length);
   std::vector<uint8> message;
   while (true) {
     received_messages_queues_[port]->Get(&message);
     if (message.empty())
       break;
 
     // MIDI devices may send a system exclusive messages even if the renderer
     // doesn't have a permission to receive it. Don't kill the renderer as
     // OnSendData() does.
     if (message[0] == kSysExByte && !has_sys_ex_permission_)
       continue;
 
     // Send to the renderer.
-    Send(new MidiMsg_DataReceived(port, message, timestamp));
+    mojo::Array<uint8_t> array = mojo::Array<uint8_t>::From(message);
+    client_->DataReceived(port, array.Pass(), timestamp);
   }
 }
 
-void MidiHost::AccumulateMidiBytesSent(size_t n) {
+void MidiServiceImpl::AccumulateMidiBytesSent(size_t n) {
   {
     base::AutoLock auto_lock(in_flight_lock_);
     if (n <= sent_bytes_in_flight_)
       sent_bytes_in_flight_ -= n;
   }
 
   if (bytes_sent_since_last_acknowledgement_ + n >=
       bytes_sent_since_last_acknowledgement_)
     bytes_sent_since_last_acknowledgement_ += n;
 
   if (bytes_sent_since_last_acknowledgement_ >=
       kAcknowledgementThresholdBytes) {
-    Send(new MidiMsg_AcknowledgeSentData(
-        bytes_sent_since_last_acknowledgement_));
+    client_->AcknowledgeSentData(
+        bytes_sent_since_last_acknowledgement_);
     bytes_sent_since_last_acknowledgement_ = 0;
   }
 }
 
 // static
-bool MidiHost::IsValidWebMIDIData(const std::vector<uint8>& data) {
+bool MidiServiceImpl::IsValidWebMIDIData(const std::vector<uint8_t>& data) {
   bool in_sysex = false;
   size_t waiting_data_length = 0;
   for (size_t i = 0; i < data.size(); ++i) {
     const uint8 current = data[i];
     if (IsSystemRealTimeMessage(current))
       continue;  // Real time message can be placed at any point.
     if (waiting_data_length > 0) {
       if (!IsDataByte(current))
         return false;  // Error: |current| should have been data byte.
       --waiting_data_length;
@@ skipping 11 matching lines @@
       continue;  // Found SysEX
     }
     waiting_data_length = media::GetMidiMessageLength(current);
     if (waiting_data_length == 0)
       return false;  // Error: |current| should have been a valid status byte.
     --waiting_data_length;  // Found status byte
   }
   return waiting_data_length == 0 && !in_sysex;
 }
 
-}  // namespace content
+}  // namespace media