root/mojo/system/message_pipe_dispatcher.cc

DEFINITIONS

1. Init
2. GetType
3. CreateRemoteMessagePipe
4. Deserialize
5. GetMessagePipeNoLock
6. GetPortNoLock
7. CancelAllWaitersNoLock
8. CloseImplNoLock
9. CreateEquivalentDispatcherAndCloseImplNoLock
10. WriteMessageImplNoLock
11. ReadMessageImplNoLock
12. AddWaiterImplNoLock
13. RemoveWaiterImplNoLock
14. GetMaximumSerializedSizeImplNoLock
15. SerializeAndCloseImplNoLock

// Copyright 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 "mojo/system/message_pipe_dispatcher.h"

#include "base/logging.h"
#include "mojo/system/channel.h"
#include "mojo/system/constants.h"
#include "mojo/system/local_message_pipe_endpoint.h"
#include "mojo/system/memory.h"
#include "mojo/system/message_in_transit.h"
#include "mojo/system/message_pipe.h"
#include "mojo/system/proxy_message_pipe_endpoint.h"

namespace mojo {
namespace system {

namespace {

const unsigned kInvalidPort = static_cast<unsigned>(-1);

struct SerializedMessagePipeDispatcher {
  MessageInTransit::EndpointId endpoint_id;
};

}  // namespace

// MessagePipeDispatcher -------------------------------------------------------

MessagePipeDispatcher::MessagePipeDispatcher()
    : port_(kInvalidPort) {
}

void MessagePipeDispatcher::Init(scoped_refptr<MessagePipe> message_pipe,
                                 unsigned port) {
  DCHECK(message_pipe.get());
  DCHECK(port == 0 || port == 1);

  message_pipe_ = message_pipe;
  port_ = port;
}

Dispatcher::Type MessagePipeDispatcher::GetType() const {
  return kTypeMessagePipe;
}

// static
std::pair<scoped_refptr<MessagePipeDispatcher>, scoped_refptr<MessagePipe> >
MessagePipeDispatcher::CreateRemoteMessagePipe() {
  scoped_refptr<MessagePipe> message_pipe(
      new MessagePipe(
          scoped_ptr<MessagePipeEndpoint>(new LocalMessagePipeEndpoint()),
          scoped_ptr<MessagePipeEndpoint>(new ProxyMessagePipeEndpoint())));
  scoped_refptr<MessagePipeDispatcher> dispatcher(new MessagePipeDispatcher());
  dispatcher->Init(message_pipe, 0);

  return std::make_pair(dispatcher, message_pipe);
}

// static
scoped_refptr<MessagePipeDispatcher> MessagePipeDispatcher::Deserialize(
    Channel* channel,
    const void* source,
    size_t size) {
  if (size != sizeof(SerializedMessagePipeDispatcher)) {
    LOG(ERROR) << "Invalid serialized message pipe dispatcher";
    return scoped_refptr<MessagePipeDispatcher>();
  }

  std::pair<scoped_refptr<MessagePipeDispatcher>, scoped_refptr<MessagePipe> >
      remote_message_pipe = CreateRemoteMessagePipe();

  MessageInTransit::EndpointId remote_id =
      static_cast<const SerializedMessagePipeDispatcher*>(source)->endpoint_id;
  MessageInTransit::EndpointId local_id =
      channel->AttachMessagePipeEndpoint(remote_message_pipe.second, 1);
  DVLOG(2) << "Deserializing message pipe dispatcher (remote ID = "
           << remote_id << ", new local ID = " << local_id << ")";

  channel->RunMessagePipeEndpoint(local_id, remote_id);
  // TODO(vtl): FIXME -- Need some error handling here.
  channel->RunRemoteMessagePipeEndpoint(local_id, remote_id);
  return remote_message_pipe.first;
}

MessagePipeDispatcher::~MessagePipeDispatcher() {
  // |Close()|/|CloseImplNoLock()| should have taken care of the pipe.
  DCHECK(!message_pipe_.get());
}

MessagePipe* MessagePipeDispatcher::GetMessagePipeNoLock() const {
  lock().AssertAcquired();
  return message_pipe_.get();
}

unsigned MessagePipeDispatcher::GetPortNoLock() const {
  lock().AssertAcquired();
  return port_;
}

void MessagePipeDispatcher::CancelAllWaitersNoLock() {
  lock().AssertAcquired();
  message_pipe_->CancelAllWaiters(port_);
}

void MessagePipeDispatcher::CloseImplNoLock() {
  lock().AssertAcquired();
  message_pipe_->Close(port_);
  message_pipe_ = NULL;
  port_ = kInvalidPort;
}

scoped_refptr<Dispatcher>
MessagePipeDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock() {
  lock().AssertAcquired();

  scoped_refptr<MessagePipeDispatcher> rv = new MessagePipeDispatcher();
  rv->Init(message_pipe_, port_);
  message_pipe_ = NULL;
  port_ = kInvalidPort;
  return scoped_refptr<Dispatcher>(rv.get());
}

MojoResult MessagePipeDispatcher::WriteMessageImplNoLock(
    const void* bytes,
    uint32_t num_bytes,
    std::vector<DispatcherTransport>* transports,
    MojoWriteMessageFlags flags) {
  DCHECK(!transports || (transports->size() > 0 &&
                         transports->size() <= kMaxMessageNumHandles));

  lock().AssertAcquired();

  if (!VerifyUserPointer<void>(bytes, num_bytes))
    return MOJO_RESULT_INVALID_ARGUMENT;
  if (num_bytes > kMaxMessageNumBytes)
    return MOJO_RESULT_RESOURCE_EXHAUSTED;

  return message_pipe_->WriteMessage(port_, bytes, num_bytes, transports,
                                     flags);
}

MojoResult MessagePipeDispatcher::ReadMessageImplNoLock(
    void* bytes,
    uint32_t* num_bytes,
    std::vector<scoped_refptr<Dispatcher> >* dispatchers,
    uint32_t* num_dispatchers,
    MojoReadMessageFlags flags) {
  lock().AssertAcquired();

  if (num_bytes) {
    if (!VerifyUserPointer<uint32_t>(num_bytes, 1))
      return MOJO_RESULT_INVALID_ARGUMENT;
    if (!VerifyUserPointer<void>(bytes, *num_bytes))
      return MOJO_RESULT_INVALID_ARGUMENT;
  }

  return message_pipe_->ReadMessage(port_, bytes, num_bytes, dispatchers,
                                    num_dispatchers, flags);
}

MojoResult MessagePipeDispatcher::AddWaiterImplNoLock(Waiter* waiter,
                                                      MojoWaitFlags flags,
                                                      MojoResult wake_result) {
  lock().AssertAcquired();
  return message_pipe_->AddWaiter(port_, waiter, flags, wake_result);
}

void MessagePipeDispatcher::RemoveWaiterImplNoLock(Waiter* waiter) {
  lock().AssertAcquired();
  message_pipe_->RemoveWaiter(port_, waiter);
}

size_t MessagePipeDispatcher::GetMaximumSerializedSizeImplNoLock(
    const Channel* /*channel*/) const {
  lock().AssertAcquired();
  return sizeof(SerializedMessagePipeDispatcher);
}

bool MessagePipeDispatcher::SerializeAndCloseImplNoLock(Channel* channel,
                                                        void* destination,
                                                        size_t* actual_size) {
  lock().AssertAcquired();

  // Convert the local endpoint to a proxy endpoint (moving the message queue).
  message_pipe_->ConvertLocalToProxy(port_);

  // Attach the new proxy endpoint to the channel.
  MessageInTransit::EndpointId endpoint_id =
      channel->AttachMessagePipeEndpoint(message_pipe_, port_);
  DCHECK_NE(endpoint_id, MessageInTransit::kInvalidEndpointId);

  DVLOG(2) << "Serializing message pipe dispatcher (local ID = " << endpoint_id
           << ")";

  // We now have a local ID. Before we can run the proxy endpoint, we need to
  // get an ack back from the other side with the remote ID.
  static_cast<SerializedMessagePipeDispatcher*>(destination)->endpoint_id =
      endpoint_id;

  message_pipe_ = NULL;
  port_ = kInvalidPort;

  *actual_size = sizeof(SerializedMessagePipeDispatcher);
  return true;
}

// MessagePipeDispatcherTransport ----------------------------------------------

MessagePipeDispatcherTransport::MessagePipeDispatcherTransport(
    DispatcherTransport transport) : DispatcherTransport(transport) {
  DCHECK_EQ(message_pipe_dispatcher()->GetType(), Dispatcher::kTypeMessagePipe);
}

}  // namespace system
}  // namespace mojo