[mojo] Implement data pipe using a shared buffer.

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
index 5566d90e428cfb1b3532ed9c2d4f24875901eeac..e89ff97a60dd23995ccfa051e66f0449c368d29a 100644
--- a/mojo/edk/system/data_pipe_consumer_dispatcher.h
+++ b/mojo/edk/system/data_pipe_consumer_dispatcher.h
@@ -9,7 +9,9 @@
 #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"
@@ -31,7 +33,13 @@ class MOJO_SYSTEM_IMPL_EXPORT DataPipeConsumerDispatcher final
 
   // 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,
+            uint32_t serialized_write_buffer_size,
+            char* serialized_read_buffer,
+            uint32_t serialized_read_buffer_size,
+            ScopedPlatformHandle shared_buffer_handle,
+            uint32_t ring_buffer_start,
+            uint32_t ring_buffer_size);
 
   // |Dispatcher| public methods:
   Type GetType() const override;
@@ -44,7 +52,7 @@ class MOJO_SYSTEM_IMPL_EXPORT DataPipeConsumerDispatcher final
               PlatformHandleVector* platform_handles);
 
  private:
-  DataPipeConsumerDispatcher(const MojoCreateDataPipeOptions& options);
+  explicit DataPipeConsumerDispatcher(const MojoCreateDataPipeOptions& options);
   ~DataPipeConsumerDispatcher() override;
 
   void InitOnIO();
@@ -85,16 +93,11 @@ class MOJO_SYSTEM_IMPL_EXPORT DataPipeConsumerDispatcher final
     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
@@ -102,18 +105,10 @@ class MOJO_SYSTEM_IMPL_EXPORT DataPipeConsumerDispatcher final
   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_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(DataPipeConsumerDispatcher);
 };