Revert r229533 "[GCM] Initial work to set up directory structure and introduce socket integration"

google_apis/gcm/base/socket_stream.h

-// Copyright 2013 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.
-//
-// Protobuf ZeroCopy[Input/Output]Stream implementations capable of using a
-// net::StreamSocket. Built to work with Protobuf CodedStreams.
-
-#ifndef GOOGLE_APIS_GCM_BASE_SOCKET_STREAM_H_
-#define GOOGLE_APIS_GCM_BASE_SOCKET_STREAM_H_
-
-#include "base/basictypes.h"
-#include "base/callback_forward.h"
-#include "base/compiler_specific.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-#include "google/protobuf/io/zero_copy_stream.h"
-#include "google_apis/gcm/base/gcm_export.h"
-#include "net/base/net_errors.h"
-
-namespace net {
-class DrainableIOBuffer;
-class IOBuffer;
-class StreamSocket;
-}  // namespace net
-
-namespace gcm {
-
-// A helper class for interacting with a net::StreamSocket that is receiving
-// protobuf encoded messages. A SocketInputStream does not take ownership of
-// the socket itself, and it is expected that the life of the input stream
-// should match the life of the socket itself (while the socket remains
-// connected). If an error is encounters, the input stream will store the error
-// in |last_error_|, and GetState() will be set to CLOSED.
-// Typical usage:
-// 1. Check the GetState() of the input stream before using it. If CLOSED, the
-//    input stream must be rebuilt (and the socket likely needs to be
-//    reconnected as an error was encountered).
-// 2. If GetState() is EMPTY, call Refresh(..), passing the maximum byte size
-//    for a message, and wait until completion. It is invalid to attempt to
-//    Refresh an input stream or read data from the stream while a Refresh is
-//    pending.
-// 3. Check GetState() again to ensure the Refresh was successful.
-// 4. Use a CodedInputStream to read from the ZeroCopyInputStream interface of
-//    the SocketInputStream. Next(..) will return true until there is no data
-//    remaining.
-// 5. Call RebuildBuffer when done reading, to shift any unread data to the
-//    start of the buffer.
-// 6. Repeat as necessary.
-class GCM_EXPORT SocketInputStream
-    : public google::protobuf::io::ZeroCopyInputStream {
- public:
-  enum State {
-    // No valid data to read. This means the buffer is either empty or all data
-    // in the buffer has already been consumed.
-    EMPTY,
-    // Valid data to read.
-    READY,
-    // In the process of reading new data from the socket.
-    READING,
-    // An permanent error occurred and the stream is now closed.
-    CLOSED,
-  };
-
-  // |socket| should already be connected.
-  explicit SocketInputStream(net::StreamSocket* socket);
-  virtual ~SocketInputStream();
-
-  // ZeroCopyInputStream implementation.
-  virtual bool Next(const void** data, int* size) OVERRIDE;
-  virtual void BackUp(int count) OVERRIDE;
-  virtual bool Skip(int count) OVERRIDE;  // Not implemented.
-  virtual int64 ByteCount() const OVERRIDE;
-
-  // The remaining amount of valid data available to be read.
-  size_t UnreadByteCount() const;
-
-  // Reads from the socket, appending a max of |byte_limit| bytes onto the read
-  // buffer. net::ERR_IO_PENDING is returned if the refresh can't complete
-  // synchronously, in which case the callback is invoked upon completion. If
-  // the refresh can complete synchronously, even in case of an error, returns
-  // net::OK without invoking callback.
-  // Note: GetState() (and possibly last_error()) should be checked upon
-  // completion to determine whether the Refresh encountered an error.
-  net::Error Refresh(const base::Closure& callback, int byte_limit);
-
-  // Rebuilds the buffer state by copying over any unread data to the beginning
-  // of the buffer and resetting the buffer read/write positions.
-  // Note: it is not valid to call Rebuild() if GetState() == CLOSED. The stream
-  // must be recreated from scratch in such a scenario.
-  void RebuildBuffer();
-
-  // Returns the last fatal error encountered. Only valid if GetState() ==
-  // CLOSED.
-  net::Error last_error() const;
-
-  // Returns the current state.
-  State GetState() const;
-
- private:
-  // Clears the local state.
-  void ResetInternal();
-
-  // Callback for Socket::Read calls.
-  void RefreshCompletionCallback(const base::Closure& callback, int result);
-
-  // Permanently closes the stream.
-  void CloseStream(net::Error error, const base::Closure& callback);
-
-  // Internal net components.
-  net::StreamSocket* const socket_;
-  const scoped_refptr<net::IOBuffer> io_buffer_;
-  // IOBuffer implementation that wraps the data within |io_buffer_| that hasn't
-  // been written to yet by Socket::Read calls.
-  const scoped_refptr<net::DrainableIOBuffer> read_buffer_;
-
-  // Starting position of the data within |io_buffer_| to consume on subsequent
-  // Next(..) call.  0 <= next_pos_ <= read_buffer_.BytesConsumed()
-  // Note: next_pos == read_buffer_.BytesConsumed() implies GetState() == EMPTY.
-  int next_pos_;
-
-  // If < net::ERR_IO_PENDING, the last net error received.
-  // Note: last_error_ == net::ERR_IO_PENDING implies GetState() == READING.
-  net::Error last_error_;
-
-  base::WeakPtrFactory<SocketInputStream> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(SocketInputStream);
-};
-
-// A helper class for writing to a SocketStream with protobuf encoded data.
-// A SocketOutputStream does not take ownership of the socket itself, and it is
-// expected that the life of the output stream should match the life of the
-// socket itself (while the socket remains connected).
-// Typical usage:
-// 1. Check the GetState() of the output stream before using it. If CLOSED, the
-//    output stream must be rebuilt (and the socket likely needs to be
-//    reconnected, as an error was encountered).
-// 2. If EMPTY, the output stream can be written via a CodedOutputStream using
-//    the ZeroCopyOutputStream interface.
-// 3. Once done writing, GetState() should be READY, so call Flush(..) to write
-//    the buffer into the StreamSocket. Wait for the callback to be invoked
-//    (it's invalid to write to an output stream while it's flushing).
-// 4. Check the GetState() again to ensure the Flush was successful. GetState()
-//    should be EMPTY again.
-// 5. Repeat.
-class GCM_EXPORT SocketOutputStream
-    : public google::protobuf::io::ZeroCopyOutputStream {
- public:
-  enum State {
-    // No valid data yet.
-    EMPTY,
-    // Ready for flushing (some data is present).
-    READY,
-    // In the process of flushing into the socket.
-    FLUSHING,
-    // A permanent error occurred, and the stream is now closed.
-    CLOSED,
-  };
-
-  // |socket| should already be connected.
-  explicit SocketOutputStream(net::StreamSocket* socket);
-  virtual ~SocketOutputStream();
-
-  // ZeroCopyOutputStream implementation.
-  virtual bool Next(void** data, int* size) OVERRIDE;
-  virtual void BackUp(int count) OVERRIDE;
-  virtual int64 ByteCount() const OVERRIDE;
-
-  // Writes the buffer into the Socket.
-  net::Error Flush(const base::Closure& callback);
-
-  // Returns the last fatal error encountered. Only valid if GetState() ==
-  // CLOSED.
-  net::Error last_error() const;
-
-  // Returns the current state.
-  State GetState() const;
-
- private:
-  void FlushCompletionCallback(const base::Closure& callback, int result);
-
-  // Internal net components.
-  net::StreamSocket* const socket_;
-  const scoped_refptr<net::IOBuffer> io_buffer_;
-  // IOBuffer implementation that wraps the data within |io_buffer_| that hasn't
-  // been written to the socket yet.
-  const scoped_refptr<net::DrainableIOBuffer> write_buffer_;
-
-  // Starting position of the data within |io_buffer_| to consume on subsequent
-  // Next(..) call.  0 <= write_buffer_.BytesConsumed() <= next_pos_
-  // Note: next_pos == 0 implies GetState() == EMPTY.
-  int next_pos_;
-
-  // If < net::ERR_IO_PENDING, the last net error received.
-  // Note: last_error_ == net::ERR_IO_PENDING implies GetState() == FLUSHING.
-  net::Error last_error_;
-
-  base::WeakPtrFactory<SocketOutputStream> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(SocketOutputStream);
-};
-
-}  // namespace gcm
-
-#endif  // GOOGLE_APIS_GCM_BASE_SOCKET_STREAM_H_