src/net/socket/socket.h

// Copyright (c) 2011 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 NET_SOCKET_SOCKET_H_
#define NET_SOCKET_SOCKET_H_

#include "net/base/completion_callback.h"
#include "net/base/net_export.h"

namespace net {

class IOBuffer;

// Represents a read/write socket.
class NET_EXPORT Socket {
 public:
  virtual ~Socket() {}

  // Reads data, up to |buf_len| bytes, from the socket.  The number of bytes
  // read is returned, or an error is returned upon failure.
  // ERR_SOCKET_NOT_CONNECTED should be returned if the socket is not currently
  // connected.  Zero is returned once to indicate end-of-file; the return value
  // of subsequent calls is undefined, and may be OS dependent.  ERR_IO_PENDING
  // is returned if the operation could not be completed synchronously, in which
  // case the result will be passed to the callback when available. If the
  // operation is not completed immediately, the socket acquires a reference to
  // the provided buffer until the callback is invoked or the socket is
  // closed.  If the socket is Disconnected before the read completes, the
  // callback will not be invoked.
  virtual int Read(IOBuffer* buf, int buf_len,
                   const CompletionCallback& callback) = 0;

  // Writes data, up to |buf_len| bytes, to the socket.  Note: data may be
  // written partially.  The number of bytes written is returned, or an error
  // is returned upon failure.  ERR_SOCKET_NOT_CONNECTED should be returned if
  // the socket is not currently connected.  The return value when the
  // connection is closed is undefined, and may be OS dependent.  ERR_IO_PENDING
  // is returned if the operation could not be completed synchronously, in which
  // case the result will be passed to the callback when available.  If the
  // operation is not completed immediately, the socket acquires a reference to
  // the provided buffer until the callback is invoked or the socket is
  // closed.  Implementations of this method should not modify the contents
  // of the actual buffer that is written to the socket.  If the socket is
  // Disconnected before the write completes, the callback will not be invoked.
  virtual int Write(IOBuffer* buf, int buf_len,
                    const CompletionCallback& callback) = 0;

  // Set the receive buffer size (in bytes) for the socket.
  // Note: changing this value can affect the TCP window size on some platforms.
  // Returns true on success, or false on failure.
  virtual bool SetReceiveBufferSize(int32 size) = 0;

  // Set the send buffer size (in bytes) for the socket.
  // Note: changing this value can affect the TCP window size on some platforms.
  // Returns true on success, or false on failure.
  virtual bool SetSendBufferSize(int32 size) = 0;
};

}  // namespace net

#endif  // NET_SOCKET_SOCKET_H_