shared_circular_buffer.h

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/*
 * Copyright 2011 Google Inc.
 *
 * Licensed 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_SHAREDMEM_SHARED_CIRCULAR_BUFFER_H_
#define PAGESPEED_KERNEL_SHAREDMEM_SHARED_CIRCULAR_BUFFER_H_

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/scoped_ptr.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/base/writer.h"

namespace net_instaweb {

class AbstractSharedMem;
class AbstractSharedMemSegment;
class AbstractMutex;
class CircularBuffer;
class MessageHandler;


class SharedCircularBuffer : public Writer {
 public:
  SharedCircularBuffer(AbstractSharedMem* shm_runtime,
                       const int buffer_capacity,
                       const GoogleString& filename_prefix,
                       const GoogleString& filename_suffix);
  virtual ~SharedCircularBuffer();
  bool InitSegment(bool parent, MessageHandler* handler);
  void Clear();
  virtual bool Write(const StringPiece& message, MessageHandler* handler);
  virtual bool Flush(MessageHandler* message_handler) { return true; }

  virtual bool Dump(Writer* writer, MessageHandler* handler);
  GoogleString ToString(MessageHandler* handler);
  void GlobalCleanup(MessageHandler* handler);

 private:
  bool InitMutex(MessageHandler* handler);
  GoogleString SegmentName() const;

  AbstractSharedMem* shm_runtime_;
  const int buffer_capacity_;
  CircularBuffer* buffer_;
  const GoogleString filename_prefix_;
  const GoogleString filename_suffix_;
  scoped_ptr<AbstractMutex> mutex_;
  scoped_ptr<AbstractSharedMemSegment> segment_;

  
};

}  

#endif