/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */


#ifndef PAGESPEED_KERNEL_BASE_WRITER_H_
#define PAGESPEED_KERNEL_BASE_WRITER_H_

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {
class MessageHandler;

// Interface for writing bytes to an output stream.
class Writer {
 public:
  Writer() {}
  virtual ~Writer();

  virtual bool Write(const StringPiece& str, MessageHandler* handler) = 0;
  virtual bool Flush(MessageHandler* message_handler) = 0;

  // Dumps the contents of what's been written to the Writer.  Many
  // Writer implementations will not be able to do this, and the default
  // implementation will return false.  But StringWriter and
  // SharedCircularBuffer can dump their contents, and override
  // this with implementations that return true.
  virtual bool Dump(Writer* writer, MessageHandler* message_handler);

 private:
  DISALLOW_COPY_AND_ASSIGN(Writer);
};

}  // namespace net_instaweb

#endif  // PAGESPEED_KERNEL_BASE_WRITER_H_
