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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef REMOTING_PROTOCOL_MESSAGE_DECODER_H_
#define REMOTING_PROTOCOL_MESSAGE_DECODER_H_
#include "base/memory/scoped_refptr.h"
#include "net/base/io_buffer.h"
#include "remoting/base/compound_buffer.h"
#include "third_party/protobuf/src/google/protobuf/message_lite.h"
namespace remoting::protocol {
// MessageDecoder uses CompoundBuffer to split the data received from the
// network into separate messages. Each message is expected to be decoded in the
// stream as follows:
// +--------------+--------------+
// | message_size | message_data |
// +--------------+--------------+
//
// Here, message_size is 4-byte integer that represents size of message_data in
// bytes. message_data - content of the message.
class MessageDecoder {
public:
MessageDecoder();
virtual ~MessageDecoder();
// Add next chunk of data. MessageDecoder retains |data| until all its bytes
// are consumed.
void AddData(scoped_refptr<net::IOBuffer> data, int data_size);
// Returns next message from the stream. Ownership of the result is passed to
// the caller. Returns nullptr if there are no complete messages yet,
// otherwise returns a buffer that contains one message.
CompoundBuffer* GetNextMessage();
private:
// Retrieves the read payload size of the current protocol buffer via |size|.
// Returns false and leaves |size| unmodified, if we do not have enough data
// to retrieve the current size.
bool GetPayloadSize(int* size);
CompoundBuffer buffer_;
// |next_payload_| stores the size of the next payload if known.
// |next_payload_known_| is true if the size of the next payload is known.
// After one payload is read this is reset to false.
int next_payload_ = 0;
bool next_payload_known_ = false;
};
} // namespace remoting::protocol
#endif // REMOTING_PROTOCOL_MESSAGE_DECODER_H_
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