Convert MIDI permission requests to use WebContents in preparation for switching the code to using …

content/browser/renderer_host/media/midi_host.cc

-// 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/browser/renderer_host/media/midi_host.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 "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 {
-
-// 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;
-
-MidiHost::MidiHost(int renderer_process_id, media::MidiManager* midi_manager)
-    : BrowserMessageFilter(MidiMsgStart),
-      renderer_process_id_(renderer_process_id),
-      has_sys_ex_permission_(false),
-      midi_manager_(midi_manager),
-      sent_bytes_in_flight_(0),
-      bytes_sent_since_last_acknowledgement_(0) {
-}
-
-MidiHost::~MidiHost() {
-  if (midi_manager_)
-    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_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-
-  return handled;
-}
-
-void MidiHost::OnStartSession(int client_id) {
-  if (midi_manager_)
-    midi_manager_->StartSession(this, client_id);
-}
-
-void MidiHost::OnSendData(uint32 port,
-                          const std::vector<uint8>& data,
-                          double timestamp) {
-  if (!midi_manager_)
-    return;
-
-  if (data.empty())
-    return;
-
-  // 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();
-    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);
-}
-
-void MidiHost::CompleteStartSession(int client_id, media::MidiResult result) {
-  MidiPortInfoList input_ports;
-  MidiPortInfoList output_ports;
-
-  if (result == media::MIDI_OK) {
-    input_ports = midi_manager_->input_ports();
-    output_ports = midi_manager_->output_ports();
-    received_messages_queues_.clear();
-    received_messages_queues_.resize(input_ports.size());
-    // ChildSecurityPolicy is set just before OnStartSession by
-    // MidiDispatcherHost. So we can safely cache the policy.
-    has_sys_ex_permission_ = ChildProcessSecurityPolicyImpl::GetInstance()->
-        CanSendMidiSysExMessage(renderer_process_id_);
-  }
-
-  Send(new MidiMsg_SessionStarted(client_id,
-                                  result,
-                                  input_ports,
-                                  output_ports));
-}
-
-void MidiHost::ReceiveMidiData(
-    uint32 port,
-    const uint8* data,
-    size_t length,
-    double timestamp) {
-  TRACE_EVENT0("midi", "MidiHost::ReceiveMidiData");
-
-  if (received_messages_queues_.size() <= port)
-    return;
-
-  // Lazy initialization
-  if (received_messages_queues_[port] == NULL)
-    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));
-  }
-}
-
-void MidiHost::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_));
-    bytes_sent_since_last_acknowledgement_ = 0;
-  }
-}
-
-// static
-bool MidiHost::IsValidWebMIDIData(const std::vector<uint8>& 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;
-      continue;  // Found data byte as expected.
-    }
-    if (in_sysex) {
-      if (data[i] == kEndOfSysExByte)
-        in_sysex = false;
-      else if (!IsDataByte(current))
-        return false;  // Error: |current| should have been data byte.
-      continue;  // Found data byte as expected.
-    }
-    if (current == kSysExByte) {
-      in_sysex = true;
-      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