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

mojo/edk/system/data_pipe_consumer_dispatcher.h

Index: mojo/edk/system/data_pipe_consumer_dispatcher.h
diff --git a/mojo/edk/system/data_pipe_consumer_dispatcher.h b/mojo/edk/system/data_pipe_consumer_dispatcher.h
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+++ b/mojo/edk/system/data_pipe_consumer_dispatcher.h
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+// 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.
+
+#ifndef MOJO_EDK_SYSTEM_DATA_PIPE_CONSUMER_DISPATCHER_H_
+#define MOJO_EDK_SYSTEM_DATA_PIPE_CONSUMER_DISPATCHER_H_
+
+#include "base/memory/ref_counted.h"
+#include "mojo/edk/system/awakable_list.h"
+#include "mojo/edk/system/dispatcher.h"
+#include "mojo/edk/system/raw_channel.h"
+#include "mojo/edk/system/system_impl_export.h"
+#include "mojo/public/cpp/system/macros.h"
+
+namespace mojo {
+namespace edk {
+
+// This is the |Dispatcher| implementation for the consumer handle for data
+// pipes (created by the Mojo primitive |MojoCreateDataPipe()|). This class is
+// thread-safe.
+class MOJO_SYSTEM_IMPL_EXPORT DataPipeConsumerDispatcher final
+    : public Dispatcher, public RawChannel::Delegate {
+ public:
+  static scoped_refptr<DataPipeConsumerDispatcher> Create(
+      const MojoCreateDataPipeOptions& options) {
+    return make_scoped_refptr(new DataPipeConsumerDispatcher(options));
+  }
+
+  // Must be called before any other methods.
+  void Init(ScopedPlatformHandle message_pipe);
+
+  // |Dispatcher| public methods:
+  Type GetType() const override;
+
+  // The "opposite" of |SerializeAndClose()|. (Typically this is called by
+  // |Dispatcher::Deserialize()|.)
+  static scoped_refptr<DataPipeConsumerDispatcher>
+  Deserialize(const void* source,
+              size_t size,
+              PlatformHandleVector* platform_handles);
+
+ private:
+  DataPipeConsumerDispatcher(const MojoCreateDataPipeOptions& options);
+  ~DataPipeConsumerDispatcher() override;
+
+  void InitOnIO();
+  void CloseOnIO();
+
+  // |Dispatcher| protected methods:
+  void CancelAllAwakablesNoLock() override;
+  void CloseImplNoLock() override;
+  scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
+      override;
+  MojoResult ReadDataImplNoLock(void* elements,
+                                uint32_t* num_bytes,
+                                MojoReadDataFlags flags) override;
+  MojoResult BeginReadDataImplNoLock(const void** buffer,
+                                     uint32_t* buffer_num_bytes,
+                                     MojoReadDataFlags flags) override;
+  MojoResult EndReadDataImplNoLock(uint32_t num_bytes_read) override;
+  HandleSignalsState GetHandleSignalsStateImplNoLock() const override;
+  MojoResult AddAwakableImplNoLock(Awakable* awakable,
+                                   MojoHandleSignals signals,
+                                   uint32_t context,
+                                   HandleSignalsState* signals_state) override;
+  void RemoveAwakableImplNoLock(Awakable* awakable,
+                                HandleSignalsState* signals_state) override;
+  void StartSerializeImplNoLock(size_t* max_size,
+                                size_t* max_platform_handles) override;
+  bool EndSerializeAndCloseImplNoLock(
+      void* destination,
+      size_t* actual_size,
+      PlatformHandleVector* platform_handles) override;
+  void TransportStarted() override;
+  void TransportEnded() override;
+  bool IsBusyNoLock() const override;
+
+  // |RawChannel::Delegate methods:
+  void OnReadMessage(
+    const MessageInTransit::View& message_view,
+    ScopedPlatformHandleVectorPtr platform_handles) override;
+  void OnError(Error error) override;
+
+  // See comment in MessagePipeDispatcher for this method.
+  void SerializeInternal();
+
+  MojoCreateDataPipeOptions options_;
+
+  // Protected by |lock()|:
+  RawChannel* channel_;  // This will be null if closed.
+
+  // Queue of incoming messages.
+  std::vector<char> data_;
+  AwakableList awakable_list_;
+
+  // If DispatcherTransport is created. Must be set before lock() is called to
+  // avoid deadlocks with RawChannel calling us.
+  base::Lock started_transport_;
+
+  bool calling_init_;
+
+  bool in_two_phase_read_;
+  uint32_t two_phase_max_bytes_read_;
+
+  bool error_;
+
+  bool serialized_;
+  std::vector<char> serialized_read_buffer_;
+  ScopedPlatformHandle serialized_platform_handle_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(DataPipeConsumerDispatcher);
+};
+
+}  // namespace edk
+}  // namespace mojo
+
+#endif  // MOJO_EDK_SYSTEM_DATA_PIPE_CONSUMER_DISPATCHER_H_