aria2/src/ValueBaseDiskWriter.h

/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2012 Tatsuhiro Tsujikawa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#ifndef D_VALUE_BASE_DISK_WRITER_H
#define D_VALUE_BASE_DISK_WRITER_H

#include "DiskWriter.h"
#include "ValueBaseStructParserStateMachine.h"

namespace aria2 {

// DiskWriter backed with ValueBaseParser. The written bytes are
// consumed by ValueBaseParser. It is only capable of sequential write
// so offset argument in write() will be ignored. It also does not
// offer read().
template <class ValueBaseParser> class ValueBaseDiskWriter : public DiskWriter {
public:
  ValueBaseDiskWriter() : parser_(&psm_) {}

  virtual ~ValueBaseDiskWriter() {}

  virtual void initAndOpenFile(int64_t totalLength = 0) CXX11_OVERRIDE
  {
    parser_.reset();
  }

  virtual void openFile(int64_t totalLength = 0) CXX11_OVERRIDE
  {
    initAndOpenFile(totalLength);
  }

  virtual void closeFile() CXX11_OVERRIDE {}

  virtual void openExistingFile(int64_t totalLength = 0) CXX11_OVERRIDE
  {
    initAndOpenFile(totalLength);
  }

  virtual int64_t size() CXX11_OVERRIDE { return 0; }

  virtual void writeData(const unsigned char* data, size_t len,
                         int64_t offset) CXX11_OVERRIDE
  {
    // Return value is ignored here but handled in finalize()
    parser_.parseUpdate(reinterpret_cast<const char*>(data), len);
  }

  virtual ssize_t readData(unsigned char* data, size_t len,
                           int64_t offset) CXX11_OVERRIDE
  {
    return 0;
  }

  int finalize() { return parser_.parseFinal(0, 0); }

  std::unique_ptr<ValueBase> getResult() { return psm_.getResult(); }

  void reset() { parser_.reset(); }

private:
  ValueBaseStructParserStateMachine psm_;
  ValueBaseParser parser_;
};

} // namespace aria2

#endif // D_VALUE_BASE_DISK_WRITER_H