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// 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/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
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