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

mojo/edk/system/data_pipe_producer_dispatcher.cc

Index: mojo/edk/system/data_pipe_producer_dispatcher.cc
diff --git a/mojo/edk/system/data_pipe_producer_dispatcher.cc b/mojo/edk/system/data_pipe_producer_dispatcher.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9950561e31d8e79c8912f5b92e883bb923df920f
--- /dev/null
+++ b/mojo/edk/system/data_pipe_producer_dispatcher.cc
@@ -0,0 +1,357 @@
+// 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_producer_dispatcher.h"
+
+#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/system/configuration.h"
+#include "mojo/edk/system/data_pipe.h"
+
+namespace mojo {
+namespace edk {
+
+void DataPipeProducerDispatcher::Init(ScopedPlatformHandle message_pipe) {
+  if (message_pipe.is_valid()) {
+    channel_ = RawChannel::Create(message_pipe.Pass());
+    internal::g_io_thread_task_runner->PostTask(
+        FROM_HERE, base::Bind(&DataPipeProducerDispatcher::InitOnIO, this));
+  }
+}
+
+void DataPipeProducerDispatcher::InitOnIO() {
+  base::AutoLock locker(lock());
+  if (channel_)
+    channel_->Init(this);
+}
+
+void DataPipeProducerDispatcher::CloseOnIO() {
+  base::AutoLock locker(lock());
+  if (channel_) {
+    channel_->Shutdown();
+    channel_ = nullptr;
+  }
+}
+
+Dispatcher::Type DataPipeProducerDispatcher::GetType() const {
+  return Type::DATA_PIPE_PRODUCER;
+}
+
+scoped_refptr<DataPipeProducerDispatcher>
+DataPipeProducerDispatcher::Deserialize(
+    const void* source,
+    size_t size,
+    PlatformHandleVector* platform_handles) {
+  MojoCreateDataPipeOptions options;
+  ScopedPlatformHandle platform_handle =
+      DataPipe::Deserialize(source, size, platform_handles, &options,
+        nullptr, 0);
+
+  scoped_refptr<DataPipeProducerDispatcher> rv(Create(options));
+  if (platform_handle.is_valid())
+    rv->Init(platform_handle.Pass());
+  return rv;
+}
+
+DataPipeProducerDispatcher::DataPipeProducerDispatcher(
+    const MojoCreateDataPipeOptions& options)
+    : options_(options), channel_(nullptr), error_(false) {
+}
+
+DataPipeProducerDispatcher::~DataPipeProducerDispatcher() {
+  // |Close()|/|CloseImplNoLock()| should have taken care of the channel.
+  DCHECK(!channel_);
+}
+
+void DataPipeProducerDispatcher::CancelAllAwakablesNoLock() {
+  lock().AssertAcquired();
+  awakable_list_.CancelAll();
+}
+
+void DataPipeProducerDispatcher::CloseImplNoLock() {
+  lock().AssertAcquired();
+  internal::g_io_thread_task_runner->PostTask(
+      FROM_HERE, base::Bind(&DataPipeProducerDispatcher::CloseOnIO, this));
+}
+
+scoped_refptr<Dispatcher>
+DataPipeProducerDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock() {
+  lock().AssertAcquired();
+
+  scoped_refptr<DataPipeProducerDispatcher> rv = Create(options_);
+  rv->channel_ = channel_;
+  channel_ = nullptr;
+  rv->options_ = options_;
+  return scoped_refptr<Dispatcher>(rv.get());
+}
+
+MojoResult DataPipeProducerDispatcher::WriteDataImplNoLock(
+    const void* elements,
+    uint32_t* num_bytes,
+    MojoWriteDataFlags flags) {
+  lock().AssertAcquired();
+  if (InTwoPhaseWrite())
+    return MOJO_RESULT_BUSY;
+  if (error_)
+    return MOJO_RESULT_FAILED_PRECONDITION;
+  if (*num_bytes % options_.element_num_bytes != 0)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+  if (*num_bytes == 0)
+    return MOJO_RESULT_OK;  // Nothing to do.
+
+  // For now, we ignore options.capacity_num_bytes as a total of all pending
+  // writes (and just treat it per message). We will implement that later if
+  // we need to. All current uses want all their data to be sent, and it's not
+  // clear that this backpressure should be done at the mojo layer or at a
+  // higher application layer.
+  bool all_or_none = flags & MOJO_WRITE_DATA_FLAG_ALL_OR_NONE;
+  uint32_t min_num_bytes_to_write = all_or_none ? *num_bytes : 0;
+  if (min_num_bytes_to_write > options_.capacity_num_bytes) {
+    // Don't return "should wait" since you can't wait for a specified amount of
+    // data.
+    return MOJO_RESULT_OUT_OF_RANGE;
+  }
+
+  uint32_t num_bytes_to_write =
+      std::min(*num_bytes, options_.capacity_num_bytes);
+  if (num_bytes_to_write == 0)
+    return MOJO_RESULT_SHOULD_WAIT;
+
+  HandleSignalsState old_state = GetHandleSignalsStateImplNoLock();
+
+  *num_bytes = num_bytes_to_write;
+  WriteDataIntoMessages(elements, num_bytes_to_write);
+
+  HandleSignalsState new_state = GetHandleSignalsStateImplNoLock();
+  if (!new_state.equals(old_state))
+    awakable_list_.AwakeForStateChange(new_state);
+  return MOJO_RESULT_OK;
+}
+
+MojoResult DataPipeProducerDispatcher::BeginWriteDataImplNoLock(
+    void** buffer,
+    uint32_t* buffer_num_bytes,
+    MojoWriteDataFlags flags) {
+  lock().AssertAcquired();
+  if (InTwoPhaseWrite())
+    return MOJO_RESULT_BUSY;
+  if (error_)
+    return MOJO_RESULT_FAILED_PRECONDITION;
+
+  bool all_or_none = flags & MOJO_WRITE_DATA_FLAG_ALL_OR_NONE;
+  uint32_t min_num_bytes_to_write = 0;
+  if (all_or_none) {
+    min_num_bytes_to_write = *buffer_num_bytes;
+    if (min_num_bytes_to_write % options_.element_num_bytes != 0)
+      return MOJO_RESULT_INVALID_ARGUMENT;
+    if (min_num_bytes_to_write > options_.capacity_num_bytes) {
+      // Don't return "should wait" since you can't wait for a specified amount
+      // of data.
+      return MOJO_RESULT_OUT_OF_RANGE;
+    }
+  }
+
+  // See comment in WriteDataImplNoLock about ignoring capacity_num_bytes.
+  if (*buffer_num_bytes == 0)
+    *buffer_num_bytes = options_.capacity_num_bytes;
+
+  two_phase_data_.resize(*buffer_num_bytes);
+  *buffer = &two_phase_data_[0];
+
+  // TODO: if buffer_num_bytes.Get() > GetConfiguration().max_message_num_bytes
+  // we can construct a MessageInTransit here. But then we need to make
+  // MessageInTransit support changing its data size later.
+
+  return MOJO_RESULT_OK;
+}
+
+MojoResult DataPipeProducerDispatcher::EndWriteDataImplNoLock(
+    uint32_t num_bytes_written) {
+  lock().AssertAcquired();
+  if (!InTwoPhaseWrite())
+    return MOJO_RESULT_FAILED_PRECONDITION;
+
+  // Note: Allow successful completion of the two-phase write even if the other
+  // side has been closed.
+  MojoResult rv = MOJO_RESULT_OK;
+  if (num_bytes_written > two_phase_data_.size() ||
+      num_bytes_written % options_.element_num_bytes != 0) {
+    rv = MOJO_RESULT_INVALID_ARGUMENT;
+  } else if (channel_) {
+    WriteDataIntoMessages(&two_phase_data_[0], num_bytes_written);
+  }
+
+  // Two-phase write ended even on failure.
+  two_phase_data_.clear();
+  // If we're now writable, we *became* writable (since we weren't writable
+  // during the two-phase write), so awake producer awakables.
+  HandleSignalsState new_state = GetHandleSignalsStateImplNoLock();
+  if (new_state.satisfies(MOJO_HANDLE_SIGNAL_WRITABLE))
+    awakable_list_.AwakeForStateChange(new_state);
+
+  return rv;
+}
+
+HandleSignalsState DataPipeProducerDispatcher::GetHandleSignalsStateImplNoLock()
+    const {
+  lock().AssertAcquired();
+
+  HandleSignalsState rv;
+  if (!error_) {
+    if (!InTwoPhaseWrite())
+      rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_WRITABLE;
+    rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_WRITABLE;
+  } else {
+    rv.satisfied_signals |= MOJO_HANDLE_SIGNAL_PEER_CLOSED;
+  }
+  rv.satisfiable_signals |= MOJO_HANDLE_SIGNAL_PEER_CLOSED;
+  return rv;
+}
+
+MojoResult DataPipeProducerDispatcher::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 DataPipeProducerDispatcher::RemoveAwakableImplNoLock(
+    Awakable* awakable,
+    HandleSignalsState* signals_state) {
+  lock().AssertAcquired();
+  awakable_list_.Remove(awakable);
+  if (signals_state)
+    *signals_state = GetHandleSignalsStateImplNoLock();
+}
+
+void DataPipeProducerDispatcher::StartSerializeImplNoLock(
+    size_t* max_size,
+    size_t* max_platform_handles) {
+  DCHECK(HasOneRef());  // Only one ref => no need to take the lock.
+
+  if (channel_) {
+    std::vector<char> temp;
+    serialized_platform_handle_ = channel_->ReleaseHandle(&temp);
+    channel_ = nullptr;
+    DCHECK(temp.empty());
+  }
+  DataPipe::StartSerialize(serialized_platform_handle_.is_valid(),
+                           false, max_size, max_platform_handles);
+}
+
+bool DataPipeProducerDispatcher::EndSerializeAndCloseImplNoLock(
+    void* destination,
+    size_t* actual_size,
+    PlatformHandleVector* platform_handles) {
+  DCHECK(HasOneRef());  // Only one ref => no need to take the lock.
+
+  DataPipe::EndSerialize(
+      options_,
+      serialized_platform_handle_.Pass(),
+      ScopedPlatformHandle(), 0,
+      destination, actual_size, platform_handles);
+  CloseImplNoLock();
+  return true;
+}
+
+void DataPipeProducerDispatcher::TransportStarted() {
+  started_transport_.Acquire();
+}
+
+void DataPipeProducerDispatcher::TransportEnded() {
+  started_transport_.Release();
+}
+
+bool DataPipeProducerDispatcher::IsBusyNoLock() const {
+  lock().AssertAcquired();
+  return InTwoPhaseWrite();
+}
+
+void DataPipeProducerDispatcher::OnReadMessage(
+    const MessageInTransit::View& message_view,
+    ScopedPlatformHandleVectorPtr platform_handles) {
+  NOTREACHED();
+}
+
+void DataPipeProducerDispatcher::OnError(Error error) {
+  switch (error) {
+    case ERROR_READ_SHUTDOWN:
+    case ERROR_READ_BROKEN:
+    case ERROR_READ_BAD_MESSAGE:
+    case ERROR_READ_UNKNOWN:
+      LOG(ERROR) << "DataPipeProducerDispatcher shouldn't read messages";
+      break;
+    case ERROR_WRITE:
+      // Write errors are slightly notable: they probably shouldn't happen under
+      // normal operation (but maybe the other side crashed).
+      LOG(WARNING) << "DataPipeProducerDispatcher write error";
+      break;
+  }
+
+  error_ = true;
+  if (started_transport_.Try()) {
+    base::AutoLock locker(lock());
+    awakable_list_.AwakeForStateChange(GetHandleSignalsStateImplNoLock());
+
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&RawChannel::Shutdown, base::Unretained(channel_)));
+    channel_ = nullptr;
+    started_transport_.Release();
+  } else {
+    // We must be waiting to call ReleaseHandle. It will call Shutdown.
+  }
+}
+
+bool DataPipeProducerDispatcher::InTwoPhaseWrite() const {
+  return !two_phase_data_.empty();
+}
+
+bool DataPipeProducerDispatcher::WriteDataIntoMessages(
+    const void* elements,
+    uint32_t num_bytes) {
+  // The maximum amount of data to send per message (make it a multiple of the
+  // element size.
+  size_t max_message_num_bytes = GetConfiguration().max_message_num_bytes;
+  max_message_num_bytes -= max_message_num_bytes % options_.element_num_bytes;
+  DCHECK_GT(max_message_num_bytes, 0u);
+
+  uint32_t offset = 0;
+  while (offset < num_bytes) {
+    uint32_t message_num_bytes =
+        std::min(static_cast<uint32_t>(max_message_num_bytes),
+                 num_bytes - offset);
+    scoped_ptr<MessageInTransit> message(new MessageInTransit(
+        MessageInTransit::Type::MESSAGE, message_num_bytes,
+        static_cast<const char*>(elements) + offset));
+    if (!channel_->WriteMessage(message.Pass())) {
+      error_ = true;
+      return false;
+    }
+
+    offset += message_num_bytes;
+  }
+
+  return true;
+}
+
+}  // namespace edk
+}  // namespace mojo