// 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 "ipc/mojo/ipc_mojo_bootstrap.h"

#include "base/logging.h"
#include "base/process/process_handle.h"
#include "ipc/ipc_message_utils.h"
#include "ipc/ipc_platform_file.h"
#include "third_party/mojo/src/mojo/edk/embedder/platform_channel_pair.h"

namespace IPC {

namespace {

// MojoBootstrap for the server process. You should create the instance
// using MojoBootstrap::Create().
class MojoServerBootstrap : public MojoBootstrap {
 public:
  MojoServerBootstrap();

 private:
  void SendClientPipe(int32 peer_pid);

  // Listener implementations
  bool OnMessageReceived(const Message& message) override;
  void OnChannelConnected(int32 peer_pid) override;

  mojo::embedder::ScopedPlatformHandle server_pipe_;
  bool connected_;

  DISALLOW_COPY_AND_ASSIGN(MojoServerBootstrap);
};

MojoServerBootstrap::MojoServerBootstrap() : connected_(false) {
}

void MojoServerBootstrap::SendClientPipe(int32 peer_pid) {
  DCHECK_EQ(state(), STATE_INITIALIZED);
  DCHECK(connected_);

  mojo::embedder::PlatformChannelPair channel_pair;
  server_pipe_ = channel_pair.PassServerHandle();

  base::Process peer_process =
#if defined(OS_WIN)
      base::Process::OpenWithAccess(peer_pid, PROCESS_DUP_HANDLE);
#else
      base::Process::Open(peer_pid);
#endif
  PlatformFileForTransit client_pipe = GetFileHandleForProcess(
#if defined(OS_POSIX)
      channel_pair.PassClientHandle().release().fd,
#else
      channel_pair.PassClientHandle().release().handle,
#endif
      peer_process.Handle(), true);
  if (client_pipe == IPC::InvalidPlatformFileForTransit()) {
#if !defined(OS_WIN)
    // GetFileHandleForProcess() only fails on Windows.
    NOTREACHED();
#endif
    LOG(WARNING) << "Failed to translate file handle for client process.";
    Fail();
    return;
  }

  scoped_ptr<Message> message(new Message());
  ParamTraits<PlatformFileForTransit>::Write(message.get(), client_pipe);
  Send(message.release());

  set_state(STATE_WAITING_ACK);
}

void MojoServerBootstrap::OnChannelConnected(int32 peer_pid) {
  DCHECK_EQ(state(), STATE_INITIALIZED);
  connected_ = true;
  SendClientPipe(peer_pid);
}

bool MojoServerBootstrap::OnMessageReceived(const Message&) {
  if (state() != STATE_WAITING_ACK) {
    set_state(STATE_ERROR);
    LOG(ERROR) << "Got inconsistent message from client.";
    return false;
  }

  set_state(STATE_READY);
  CHECK(server_pipe_.is_valid());
  delegate()->OnPipeAvailable(
      mojo::embedder::ScopedPlatformHandle(server_pipe_.release()));

  return true;
}

// MojoBootstrap for client processes. You should create the instance
// using MojoBootstrap::Create().
class MojoClientBootstrap : public MojoBootstrap {
 public:
  MojoClientBootstrap();

 private:
  // Listener implementations
  bool OnMessageReceived(const Message& message) override;
  void OnChannelConnected(int32 peer_pid) override;

  DISALLOW_COPY_AND_ASSIGN(MojoClientBootstrap);
};

MojoClientBootstrap::MojoClientBootstrap() {
}

bool MojoClientBootstrap::OnMessageReceived(const Message& message) {
  if (state() != STATE_INITIALIZED) {
    set_state(STATE_ERROR);
    LOG(ERROR) << "Got inconsistent message from server.";
    return false;
  }

  PlatformFileForTransit pipe;
  base::PickleIterator iter(message);
  if (!ParamTraits<PlatformFileForTransit>::Read(&message, &iter, &pipe)) {
    LOG(WARNING) << "Failed to read a file handle from bootstrap channel.";
    message.set_dispatch_error();
    return false;
  }

  // Sends ACK back.
  Send(new Message());
  set_state(STATE_READY);
  delegate()->OnPipeAvailable(
      mojo::embedder::ScopedPlatformHandle(mojo::embedder::PlatformHandle(
          PlatformFileForTransitToPlatformFile(pipe))));

  return true;
}

void MojoClientBootstrap::OnChannelConnected(int32 peer_pid) {
}

}  // namespace

// MojoBootstrap

// static
scoped_ptr<MojoBootstrap> MojoBootstrap::Create(ChannelHandle handle,
                                                Channel::Mode mode,
                                                Delegate* delegate,
                                                AttachmentBroker* broker) {
  CHECK(mode == Channel::MODE_CLIENT || mode == Channel::MODE_SERVER);
  scoped_ptr<MojoBootstrap> self =
      mode == Channel::MODE_CLIENT
          ? scoped_ptr<MojoBootstrap>(new MojoClientBootstrap())
          : scoped_ptr<MojoBootstrap>(new MojoServerBootstrap());

  scoped_ptr<Channel> bootstrap_channel =
      Channel::Create(handle, mode, self.get(), broker);
  self->Init(bootstrap_channel.Pass(), delegate);
  return self.Pass();
}

MojoBootstrap::MojoBootstrap() : delegate_(NULL), state_(STATE_INITIALIZED) {
}

MojoBootstrap::~MojoBootstrap() {
}

void MojoBootstrap::Init(scoped_ptr<Channel> channel, Delegate* delegate) {
  channel_ = channel.Pass();
  delegate_ = delegate;
}

bool MojoBootstrap::Connect() {
  return channel_->Connect();
}

base::ProcessId MojoBootstrap::GetSelfPID() const {
  return channel_->GetSelfPID();
}

void MojoBootstrap::OnBadMessageReceived(const Message& message) {
  Fail();
}

void MojoBootstrap::OnChannelError() {
  if (state_ == STATE_READY || state_ == STATE_ERROR)
    return;
  DLOG(WARNING) << "Detected error on Mojo bootstrap channel.";
  Fail();
}

void MojoBootstrap::Fail() {
  set_state(STATE_ERROR);
  delegate()->OnBootstrapError();
}

bool MojoBootstrap::HasFailed() const {
  return state() == STATE_ERROR;
}

bool MojoBootstrap::Send(Message* message) {
  return channel_->Send(message);
}

#if defined(OS_POSIX) && !defined(OS_NACL)
int MojoBootstrap::GetClientFileDescriptor() const {
  return channel_->GetClientFileDescriptor();
}

base::ScopedFD MojoBootstrap::TakeClientFileDescriptor() {
  return channel_->TakeClientFileDescriptor();
}
#endif  // defined(OS_POSIX) && !defined(OS_NACL)

}  // namespace IPC