1 // Copyright 2016 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 MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_LIB_MESSAGE_BUFFER_H_
6 #define MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_LIB_MESSAGE_BUFFER_H_
7 
8 #include <stddef.h>
9 #include <stdint.h>
10 
11 #include <utility>
12 
13 #include "base/macros.h"
14 #include "mojo/public/cpp/bindings/lib/buffer.h"
15 #include "mojo/public/cpp/system/message.h"
16 
17 namespace mojo {
18 namespace internal {
19 
20 // A fixed-size Buffer implementation using a Mojo message object for storage.
21 class MessageBuffer : public Buffer {
22  public:
23   // Initializes this buffer to carry a fixed byte capacity and no handles.
24   MessageBuffer(size_t capacity, bool zero_initialized);
25 
26   // Initializes this buffer from an existing Mojo MessageHandle.
27   MessageBuffer(ScopedMessageHandle message, uint32_t num_bytes);
28 
29   ~MessageBuffer() override;
30 
data()31   void* data() const { return buffer_; }
data_num_bytes()32   uint32_t data_num_bytes() const { return data_num_bytes_; }
33 
34   // Buffer:
35   void* Allocate(size_t delta) override;
36 
TakeMessage()37   ScopedMessageHandle TakeMessage() { return std::move(message_); }
38 
39   void NotifyBadMessage(const std::string& error);
40 
41  private:
42   uint32_t data_num_bytes_ = 0;
43   ScopedMessageHandle message_;
44   void* buffer_;
45 
46   uint32_t bytes_claimed_ = 0;
47 
48   DISALLOW_COPY_AND_ASSIGN(MessageBuffer);
49 };
50 
51 }  // namespace internal
52 }  // namespace mojo
53 
54 #endif  // MOJO_PUBLIC_CPP_BINDINGS_MESSAGE_LIB_MESSAGE_BUFFER_H_
55