[mojo] Implement data pipe using a shared buffer.

mojo/edk/system/data_pipe_consumer_dispatcher.h

 // 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 <stddef.h>
 #include <stdint.h>
 
 #include "base/memory/ref_counted.h"
+#include "mojo/edk/embedder/platform_shared_buffer.h"
 #include "mojo/edk/system/awakable_list.h"
+#include "mojo/edk/system/data_pipe.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,
-            char* serialized_read_buffer, size_t serialized_read_buffer_size);
+            char* serialized_write_buffer,
+            size_t serialized_write_buffer_size,
+            char* serialized_read_buffer,
+            size_t serialized_read_buffer_size,
+            ScopedPlatformHandle shared_buffer_handle,
+            size_t ring_buffer_start,
+            size_t ring_buffer_size);
 
   // |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);
+  explicit DataPipeConsumerDispatcher(const MojoCreateDataPipeOptions& options);
   ~DataPipeConsumerDispatcher() override;
 
   void InitOnIO();
   void CloseOnIO();
 
   // |Dispatcher| protected methods:
   void CancelAllAwakablesNoLock() override;
   void CloseImplNoLock() override;
   scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
       override;
@@ skipping 20 matching lines @@
   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();
+  bool ProcessCommand(const DataPipeCommandHeader& command,
+                      ScopedPlatformHandleVectorPtr platform_handles);
 
-  MojoCreateDataPipeOptions options_;
+  scoped_refptr<DataPipe> data_pipe_;
 
-  // 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 peer_closed_;
 
   bool in_two_phase_read_;
-  uint32_t two_phase_max_bytes_read_;
-  // If we get data from the channel while we're in two-phase read, we can't
-  // resize data_ since it's being used. So instead we store it temporarly.
-  std::vector<char> data_received_during_two_phase_read_;
-
-  bool error_;
-
-  bool serialized_;
-  std::vector<char> serialized_read_buffer_;
-  ScopedPlatformHandle serialized_platform_handle_;
+  size_t two_phase_max_bytes_read_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(DataPipeConsumerDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_DATA_PIPE_CONSUMER_DISPATCHER_H_