ipc/mojo/ipc_message_pipe_reader.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef IPC_IPC_MESSAGE_PIPE_READER_H_
   6 #define IPC_IPC_MESSAGE_PIPE_READER_H_
   7
   8 #include <vector>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "ipc/ipc_message.h"
  13 #include "third_party/mojo/src/mojo/public/c/environment/async_waiter.h"
  14 #include "third_party/mojo/src/mojo/public/cpp/system/core.h"
  15
  16 namespace IPC {
  17 namespace internal {
  18
  19 class AsyncHandleWaiter;
  20
  21 // A helper class to handle bytestream directly over mojo::MessagePipe
  22 // in template-method pattern. MessagePipeReader manages the lifetime
  23 // of given MessagePipe and participates the event loop, and
  24 // read the stream and call the client when it is ready.
  25 //
  26 // Each client has to:
  27 //
  28 //  * Provide a subclass implemenation of a specific use of a MessagePipe
  29 //    and implement callbacks.
  30 //  * Create the subclass instance with a MessagePipeHandle.
  31 //    The constructor automatically start listening on the pipe.
  32 //
  33 // MessageReader has to be used in IO thread. It isn't thread-safe.
  34 //
  35 class MessagePipeReader {
  36  public:
  37   class Delegate {
  38    public:
  39     virtual void OnMessageReceived(Message& message) = 0;
  40     virtual void OnPipeClosed(MessagePipeReader* reader) = 0;
  41     virtual void OnPipeError(MessagePipeReader* reader) = 0;
  42   };
  43
  44   // Delay the object deletion using the current message loop.
  45   // This is intended to used by MessagePipeReader owners.
  46   class DelayedDeleter {
  47    public:
  48     typedef base::DefaultDeleter<MessagePipeReader> DefaultType;
  49
  50     static void DeleteNow(MessagePipeReader* ptr) { delete ptr; }
  51
  52     DelayedDeleter() {}
  53     explicit DelayedDeleter(const DefaultType&) {}
  54     DelayedDeleter& operator=(const DefaultType&) { return *this; }
  55
  56     void operator()(MessagePipeReader* ptr) const;
  57   };
  58
  59   // Both parameters must be non-null.
  60   // Build a reader that reads messages from |handle| and lets |delegate| know.
  61   // Note that MessagePipeReader doesn't delete |delete|.
  62   MessagePipeReader(mojo::ScopedMessagePipeHandle handle, Delegate* delegate);
  63   virtual ~MessagePipeReader();
  64
  65   MojoHandle handle() const { return pipe_.get().value(); }
  66
  67   // Returns received bytes.
  68   const std::vector<char>& data_buffer() const {
  69     return data_buffer_;
  70   }
  71
  72   // Delegate received handles ownership. The subclass should take the
  73   // ownership over in its OnMessageReceived(). They will leak otherwise.
  74   void TakeHandleBuffer(std::vector<MojoHandle>* handle_buffer) {
  75     handle_buffer_.swap(*handle_buffer);
  76   }
  77
  78   // Close and destroy the MessagePipe.
  79   void Close();
  80   // Close the mesage pipe with notifying the client with the error.
  81   void CloseWithError(MojoResult error);
  82   // Return true if the MessagePipe is alive.
  83   bool IsValid() { return pipe_.is_valid(); }
  84
  85   bool Send(scoped_ptr<Message> message);
  86   void ReadMessagesThenWait();
  87
  88  private:
  89   void OnMessageReceived();
  90   void OnPipeClosed();
  91   void OnPipeError(MojoResult error);
  92
  93   MojoResult ReadMessageBytes();
  94   void PipeIsReady(MojoResult wait_result);
  95   void ReadAvailableMessages();
  96
  97   std::vector<char>  data_buffer_;
  98   std::vector<MojoHandle> handle_buffer_;
  99   mojo::ScopedMessagePipeHandle pipe_;
 100   // |delegate_| and |async_waiter_| are null once the message pipe is closed.
 101   Delegate* delegate_;
 102   scoped_ptr<AsyncHandleWaiter> async_waiter_;
 103
 104   DISALLOW_COPY_AND_ASSIGN(MessagePipeReader);
 105 };
 106
 107 }  // namespace internal
 108 }  // namespace IPC
 109
 110 #endif  // IPC_IPC_MESSAGE_PIPE_READER_H_