Add a Mojo EDK for Chrome that uses one OS pipe per message pipe.

mojo/edk/system/data_pipe_consumer_dispatcher.cc

+// 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/edk/system/data_pipe_consumer_dispatcher.h"
+
+#include <algorithm>
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "mojo/edk/embedder/embedder_internal.h"
+#include "mojo/edk/embedder/platform_shared_buffer.h"
+#include "mojo/edk/embedder/platform_support.h"
+#include "mojo/edk/system/data_pipe.h"
+
+namespace mojo {
+namespace edk {
+
+struct SharedMemoryHeader {
+  uint32_t data_size;
+  uint32_t read_buffer_size;
+};
+
+void DataPipeConsumerDispatcher::Init(ScopedPlatformHandle message_pipe) {
+  if (message_pipe.is_valid()) {
+    channel_ = RawChannel::Create(message_pipe.Pass());
+    if (!serialized_read_buffer_.empty())
+      channel_->SetInitialReadBufferData(
+          &serialized_read_buffer_[0], serialized_read_buffer_.size());
+    serialized_read_buffer_.clear();
+    internal::g_io_thread_task_runner->PostTask(
+        FROM_HERE, base::Bind(&DataPipeConsumerDispatcher::InitOnIO, this));
+  }
+}
+
+void DataPipeConsumerDispatcher::InitOnIO() {
+  base::AutoLock locker(lock());
+  calling_init_ = true;
+  if (channel_)
+    channel_->Init(this);
+  calling_init_ = false;
+}
+
+void DataPipeConsumerDispatcher::CloseOnIO() {
+  base::AutoLock locker(lock());
+  if (channel_) {
+    channel_->Shutdown();
+    channel_ = nullptr;
+  }
+}
+
+Dispatcher::Type DataPipeConsumerDispatcher::GetType() const {
+  return Type::DATA_PIPE_CONSUMER;
+}
+
+scoped_refptr<DataPipeConsumerDispatcher>
+DataPipeConsumerDispatcher::Deserialize(
+    const void* source,
+    size_t size,
+    PlatformHandleVector* platform_handles) {
+  MojoCreateDataPipeOptions options;
+  ScopedPlatformHandle shared_memory_handle;
+  size_t shared_memory_size = 0;
+
+  ScopedPlatformHandle platform_handle =
+      DataPipe::Deserialize(source, size, platform_handles, &options,
+      &shared_memory_handle, &shared_memory_size);
+
+  scoped_refptr<DataPipeConsumerDispatcher> rv(Create(options));
+
+  if (shared_memory_size) {
+    scoped_refptr<PlatformSharedBuffer> shared_buffer(
+        internal::g_platform_support->CreateSharedBufferFromHandle(
+            shared_memory_size, shared_memory_handle.Pass()));;
+    scoped_ptr<PlatformSharedBufferMapping> mapping(
+        shared_buffer->Map(0, shared_memory_size));
+    char* buffer = static_cast<char*>(mapping->GetBase());
+    SharedMemoryHeader* header = reinterpret_cast<SharedMemoryHeader*>(buffer);
+    buffer+= sizeof(SharedMemoryHeader);
+    if (header->data_size) {
+      rv->data_.resize(header->data_size);
+      memcpy(&rv->data_[0], buffer, header->data_size);
+      buffer += header->data_size;
+    }
+    if (header->read_buffer_size) {
+      rv->serialized_read_buffer_.resize(header->read_buffer_size);
+      memcpy(&rv->serialized_read_buffer_[0], buffer, header->read_buffer_size);
+      buffer += header->read_buffer_size;
+    }
+
+  }
+
+  if (platform_handle.is_valid())
+    rv->Init(platform_handle.Pass());
+  return rv;
+}
+
+DataPipeConsumerDispatcher::DataPipeConsumerDispatcher(
+    const MojoCreateDataPipeOptions& options)
+    : options_(options),
+      channel_(nullptr),
+      calling_init_(false),
+      in_two_phase_read_(false),
+      two_phase_max_bytes_read_(0),
+      error_(false),
+      serialized_(false) {
+}
+
+DataPipeConsumerDispatcher::~DataPipeConsumerDispatcher() {
+  // |Close()|/|CloseImplNoLock()| should have taken care of the channel.
+  DCHECK(!channel_);
+}
+
+void DataPipeConsumerDispatcher::CancelAllAwakablesNoLock() {
+  lock().AssertAcquired();
+  awakable_list_.CancelAll();
+}
+
+void DataPipeConsumerDispatcher::CloseImplNoLock() {
+  lock().AssertAcquired();
+  internal::g_io_thread_task_runner->PostTask(
+      FROM_HERE, base::Bind(&DataPipeConsumerDispatcher::CloseOnIO, this));
+}
+
+scoped_refptr<Dispatcher>
+DataPipeConsumerDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock() {
+  lock().AssertAcquired();
+
+  SerializeInternal();
+
+  scoped_refptr<DataPipeConsumerDispatcher> rv = Create(options_);
+  rv->channel_ = channel_;
+  channel_ = nullptr;
+  rv->options_ = options_;
+  data_.swap(rv->data_);
+  serialized_read_buffer_.swap(rv->serialized_read_buffer_);
+  rv->serialized_platform_handle_ = serialized_platform_handle_.Pass();
+  rv->serialized_ = true;
+
+  return scoped_refptr<Dispatcher>(rv.get());
+}
+
+MojoResult DataPipeConsumerDispatcher::ReadDataImplNoLock(
+    void* elements,
+    uint32_t* num_bytes,
+    MojoReadDataFlags flags) {
+  lock().AssertAcquired();
+  if (in_two_phase_read_)
+    return MOJO_RESULT_BUSY;
+
+  if ((flags & MOJO_READ_DATA_FLAG_QUERY)) {
+    if ((flags & MOJO_READ_DATA_FLAG_PEEK) ||
+        (flags & MOJO_READ_DATA_FLAG_DISCARD))
+      return MOJO_RESULT_INVALID_ARGUMENT;
+    DCHECK(!(flags & MOJO_READ_DATA_FLAG_DISCARD));  // Handled above.
+    DVLOG_IF(2, elements)
+        << "Query mode: ignoring non-null |elements|";
+    *num_bytes = static_cast<uint32_t>(data_.size());
+    return MOJO_RESULT_OK;
+  }
+
+  bool discard = false;
+  if ((flags & MOJO_READ_DATA_FLAG_DISCARD)) {
+    // These flags are mutally exclusive.
+    if (flags & MOJO_READ_DATA_FLAG_PEEK)
+      return MOJO_RESULT_INVALID_ARGUMENT;
+    DVLOG_IF(2, elements)
+        << "Discard mode: ignoring non-null |elements|";
+    discard = true;
+  }
+
+  uint32_t max_num_bytes_to_read = *num_bytes;
+  if (max_num_bytes_to_read % options_.element_num_bytes != 0)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  bool all_or_none = flags & MOJO_READ_DATA_FLAG_ALL_OR_NONE;
+  uint32_t min_num_bytes_to_read =
+      all_or_none ? max_num_bytes_to_read : 0;
+
+  if (min_num_bytes_to_read > data_.size())
+    return error_ ? MOJO_RESULT_FAILED_PRECONDITION : MOJO_RESULT_OUT_OF_RANGE;
+
+  uint32_t bytes_to_read = std::min(max_num_bytes_to_read,
+                                    static_cast<uint32_t>(data_.size()));
+  if (bytes_to_read == 0)
+    return error_ ? MOJO_RESULT_FAILED_PRECONDITION : MOJO_RESULT_SHOULD_WAIT;
+
+  if (!discard)
+    memcpy(elements, &data_[0], bytes_to_read);
+  *num_bytes = bytes_to_read;
+
+  bool peek = !!(flags & MOJO_READ_DATA_FLAG_PEEK);
+  if (discard || !peek)
+    data_.erase(data_.begin(), data_.begin() + bytes_to_read);
+
+  return MOJO_RESULT_OK;
+}
+
+MojoResult DataPipeConsumerDispatcher::BeginReadDataImplNoLock(
+    const void** buffer,
+    uint32_t* buffer_num_bytes,
+    MojoReadDataFlags flags) {
+  lock().AssertAcquired();
+  if (in_two_phase_read_)
+    return MOJO_RESULT_BUSY;
+
+  // These flags may not be used in two-phase mode.
+  if ((flags & MOJO_READ_DATA_FLAG_DISCARD) ||
+      (flags & MOJO_READ_DATA_FLAG_QUERY) ||
+      (flags & MOJO_READ_DATA_FLAG_PEEK))
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  bool all_or_none = flags & MOJO_READ_DATA_FLAG_ALL_OR_NONE;
+  uint32_t min_num_bytes_to_read = 0;
+  if (all_or_none) {
+    min_num_bytes_to_read = *buffer_num_bytes;
+    if (min_num_bytes_to_read % options_.element_num_bytes != 0)
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
+
+  uint32_t max_num_bytes_to_read = static_cast<uint32_t>(data_.size());
+  if (min_num_bytes_to_read > max_num_bytes_to_read)
+    return error_ ? MOJO_RESULT_FAILED_PRECONDITION : MOJO_RESULT_OUT_OF_RANGE;
+  if (max_num_bytes_to_read == 0)
+    return error_ ? MOJO_RESULT_FAILED_PRECONDITION : MOJO_RESULT_SHOULD_WAIT;
+
+  in_two_phase_read_ = true;
+  *buffer = &data_[0];
+  *buffer_num_bytes = max_num_bytes_to_read;
+  two_phase_max_bytes_read_ = max_num_bytes_to_read;
+
+  return MOJO_RESULT_OK;
+}
+
+MojoResult DataPipeConsumerDispatcher::EndReadDataImplNoLock(
+    uint32_t num_bytes_read) {
+  lock().AssertAcquired();
+  if (!in_two_phase_read_)
+    return MOJO_RESULT_FAILED_PRECONDITION;
+
+  MojoResult rv;
+  if (num_bytes_read > two_phase_max_bytes_read_ ||
+      num_bytes_read % options_.element_num_bytes != 0) {
+    rv = MOJO_RESULT_INVALID_ARGUMENT;
+  } else {
+    rv = MOJO_RESULT_OK;
+    data_.erase(data_.begin(), data_.begin() + num_bytes_read);
+  }
+
+  in_two_phase_read_ = false;
+  two_phase_max_bytes_read_ = 0;
+
+  // If we're now readable, we *became* readable (since we weren't readable
+  // during the two-phase read), so awake consumer awakables.
+  HandleSignalsState new_state = GetHandleSignalsStateImplNoLock();
+  if (new_state.satisfies(MOJO_HANDLE_SIGNAL_READABLE))
+    awakable_list_.AwakeForStateChange(new_state);
+
+  return rv;
+}
+
+HandleSignalsState DataPipeConsumerDispatcher::GetHandleSignalsStateImplNoLock()
+    const {
+  lock().AssertAcquired();
+
+  HandleSignalsState rv;
+  if (!data_.empty()) {
+    if (!in_two_phase_read_)
+      rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_READABLE;
+    rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_READABLE;
+  } else if (!error_) {
+    rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_READABLE;
+  }
+
+  if (error_)
+    rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_PEER_CLOSED;
+  rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_PEER_CLOSED;
+  return rv;
+}
+
+MojoResult DataPipeConsumerDispatcher::AddAwakableImplNoLock(
+    Awakable* awakable,
+    MojoHandleSignals signals,
+    uint32_t context,
+    HandleSignalsState* signals_state) {
+  lock().AssertAcquired();
+  HandleSignalsState state = GetHandleSignalsStateImplNoLock();
+  if (state.satisfies(signals)) {
+    if (signals_state)
+      *signals_state = state;
+    return MOJO_RESULT_ALREADY_EXISTS;
+  }
+  if (!state.can_satisfy(signals)) {
+    if (signals_state)
+      *signals_state = state;
+    return MOJO_RESULT_FAILED_PRECONDITION;
+  }
+
+  awakable_list_.Add(awakable, signals, context);
+  return MOJO_RESULT_OK;
+}
+
+void DataPipeConsumerDispatcher::RemoveAwakableImplNoLock(
+    Awakable* awakable,
+    HandleSignalsState* signals_state) {
+  lock().AssertAcquired();
+  awakable_list_.Remove(awakable);
+  if (signals_state)
+    *signals_state = GetHandleSignalsStateImplNoLock();
+}
+
+void DataPipeConsumerDispatcher::StartSerializeImplNoLock(
+    size_t* max_size,
+    size_t* max_platform_handles) {
+  //DCHECK(HasOneRef());  // Only one ref => no need to take the lock.
+
+  if (!serialized_) {
+    // handles the case where we have messages read off rawchannel but not
+    // ready by MojoReadMessage.
+    SerializeInternal();
+  }
+
+  DataPipe::StartSerialize(serialized_platform_handle_.is_valid(),
+                           !data_.empty(),
+                           max_size, max_platform_handles);
+}
+
+bool DataPipeConsumerDispatcher::EndSerializeAndCloseImplNoLock(
+    void* destination,
+    size_t* actual_size,
+    PlatformHandleVector* platform_handles) {
+  //DCHECK(HasOneRef());  // Only one ref => no need to take the lock.
+
+  ScopedPlatformHandle shared_memory_handle;
+  size_t shared_memory_size =  data_.size() + serialized_read_buffer_.size();
+  if (shared_memory_size) {
+    shared_memory_size += sizeof(SharedMemoryHeader);
+    SharedMemoryHeader header;
+    header.data_size = static_cast<uint32_t>(data_.size());
+    header.read_buffer_size =
+        static_cast<uint32_t>(serialized_read_buffer_.size());
+
+    scoped_refptr<PlatformSharedBuffer> shared_buffer(
+        internal::g_platform_support->CreateSharedBuffer(
+            shared_memory_size));
+    scoped_ptr<PlatformSharedBufferMapping> mapping(
+        shared_buffer->Map(0, shared_memory_size));
+
+    char* start = static_cast<char*>(mapping->GetBase());
+    memcpy(start, &header, sizeof(SharedMemoryHeader));
+    start += sizeof(SharedMemoryHeader);
+
+    if (!data_.empty()) {
+      memcpy(start, &data_[0], data_.size());
+      start += data_.size();
+    }
+
+    if (!serialized_read_buffer_.empty()) {
+      memcpy(start, &serialized_read_buffer_[0],
+             serialized_read_buffer_.size());
+      start += serialized_read_buffer_.size();
+    }
+
+    shared_memory_handle.reset(shared_buffer->PassPlatformHandle().release());
+  }
+
+  DataPipe::EndSerialize(
+      options_,
+      serialized_platform_handle_.Pass(),
+      shared_memory_handle.Pass(),
+      shared_memory_size, destination, actual_size,
+      platform_handles);
+  CloseImplNoLock();
+  return true;
+}
+
+void DataPipeConsumerDispatcher::TransportStarted() {
+  started_transport_.Acquire();
+}
+
+void DataPipeConsumerDispatcher::TransportEnded() {
+  started_transport_.Release();
+
+  base::AutoLock locker(lock());
+
+  // If transporting of DP failed, we might have got more data and didn't awake
+  // for.
+  // TODO(jam): should we care about only alerting if it was empty before
+  // TransportStarted?
+  if (!data_.empty())
+    awakable_list_.AwakeForStateChange(GetHandleSignalsStateImplNoLock());
+}
+
+bool DataPipeConsumerDispatcher::IsBusyNoLock() const {
+  lock().AssertAcquired();
+  return in_two_phase_read_;
+}
+
+void DataPipeConsumerDispatcher::OnReadMessage(
+    const MessageInTransit::View& message_view,
+    ScopedPlatformHandleVectorPtr platform_handles) {
+  scoped_ptr<MessageInTransit> message(new MessageInTransit(message_view));
+
+  if (started_transport_.Try()) {
+    // we're not in the middle of being sent
+
+    // Can get synchronously called back in Init if there was initial data.
+    scoped_ptr<base::AutoLock> locker;
+    if (!calling_init_) {
+      locker.reset(new base::AutoLock(lock()));
+    }
+
+    size_t old_size = data_.size();
+    data_.resize(old_size + message->num_bytes());
+    memcpy(&data_[old_size], message->bytes(), message->num_bytes());
+    if (!old_size)
+      awakable_list_.AwakeForStateChange(GetHandleSignalsStateImplNoLock());
+    started_transport_.Release();
+  } else {
+    size_t old_size = data_.size();
+    data_.resize(old_size + message->num_bytes());
+    memcpy(&data_[old_size], message->bytes(), message->num_bytes());
+  }
+}
+
+void DataPipeConsumerDispatcher::OnError(Error error) {
+  switch (error) {
+    case ERROR_READ_SHUTDOWN:
+      // The other side was cleanly closed, so this isn't actually an error.
+      DVLOG(1) << "DataPipeConsumerDispatcher read error (shutdown)";
+      break;
+    case ERROR_READ_BROKEN:
+      LOG(ERROR) << "DataPipeConsumerDispatcher read error (connection broken)";
+      break;
+    case ERROR_READ_BAD_MESSAGE:
+      // Receiving a bad message means either a bug, data corruption, or
+      // malicious attack (probably due to some other bug).
+      LOG(ERROR) << "DataPipeConsumerDispatcher read error (received bad "
+                 << "message)";
+      break;
+    case ERROR_READ_UNKNOWN:
+      LOG(ERROR) << "DataPipeConsumerDispatcher read error (unknown)";
+      break;
+    case ERROR_WRITE:
+      LOG(ERROR) << "DataPipeConsumerDispatcher shouldn't write messages";
+      break;
+  }
+
+  error_ = true;
+  if (started_transport_.Try()) {
+    base::AutoLock locker(lock());
+    awakable_list_.AwakeForStateChange(GetHandleSignalsStateImplNoLock());
+    started_transport_.Release();
+
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&RawChannel::Shutdown, base::Unretained(channel_)));
+    channel_ = nullptr;
+  } else {
+    // We must be waiting to call ReleaseHandle. It will call Shutdown.
+  }
+}
+
+void DataPipeConsumerDispatcher::SerializeInternal() {
+  // need to stop watching handle immediately, even tho not on IO thread, so
+  // that other messages aren't read after this.
+  if (channel_) {
+    serialized_platform_handle_ =
+        channel_->ReleaseHandle(&serialized_read_buffer_);
+
+    channel_ = nullptr;
+    serialized_ = true;
+  }
+}
+
+}  // namespace edk
+}  // namespace mojo