async_cache.h

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/*
 * Copyright 2012 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_CACHE_ASYNC_CACHE_H_
#define PAGESPEED_KERNEL_CACHE_ASYNC_CACHE_H_

#include "pagespeed/kernel/base/atomic_bool.h"
#include "pagespeed/kernel/base/atomic_int32.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/shared_string.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/cache/cache_interface.h"
#include "pagespeed/kernel/thread/queued_worker_pool.h"

namespace net_instaweb {

class AsyncCache : public CacheInterface {
 public:
  static const int64 kMaxQueueSize = 2000;

  AsyncCache(CacheInterface* cache, QueuedWorkerPool* pool);
  virtual ~AsyncCache();

  virtual void Get(const GoogleString& key, Callback* callback);
  virtual void Put(const GoogleString& key, const SharedString& value);
  virtual void Delete(const GoogleString& key);
  virtual void MultiGet(MultiGetRequest* request);
  static GoogleString FormatName(StringPiece cache);
  virtual GoogleString Name() const { return FormatName(cache_->Name()); }
  virtual bool IsBlocking() const { return false; }

  virtual void ShutDown();

  void CancelPendingOperations() { sequence_->CancelPendingFunctions(); }

  virtual bool IsHealthy() const {
    return !stopped_.value() && cache_->IsHealthy();
  }

  int32 outstanding_operations() { return outstanding_operations_.value(); }

 private:
  void DoGet(GoogleString* key, Callback* callback);
  void CancelGet(GoogleString* key, Callback* callback);

  void DoMultiGet(MultiGetRequest* request);
  void CancelMultiGet(MultiGetRequest* request);

  void DoPut(GoogleString* key, const SharedString value);
  void CancelPut(GoogleString* key, const SharedString value);
  void DoDelete(GoogleString* key);
  void CancelDelete(GoogleString* key);

  void MultiGetReportNotFound(MultiGetRequest* request);

  CacheInterface* cache_;
  QueuedWorkerPool::Sequence* sequence_;
  AtomicBool stopped_;
  AtomicInt32 outstanding_operations_;

  
};

}  

#endif