apr_mem_cache.h

Go to the documentation of this file.

/*
 * 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_SYSTEM_APR_MEM_CACHE_H_
#define PAGESPEED_SYSTEM_APR_MEM_CACHE_H_

#include <cstddef>
#include <vector>

#include "pagespeed/kernel/base/atomic_bool.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/shared_string.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/timer.h"
#include "pagespeed/kernel/cache/cache_interface.h"
#include "pagespeed/system/external_server_spec.h"

struct apr_memcache2_t;
struct apr_memcache2_server_t;
struct apr_pool_t;

namespace net_instaweb {

class Hasher;
class MessageHandler;
class Statistics;
class UpDownCounter;
class Variable;

class AprMemCache : public CacheInterface {
 public:
  static const size_t kValueSizeThreshold = 1 * 1000 * 1000;

  static const int64 kHealthCheckpointIntervalMs = 30 * Timer::kSecondMs;

  static const int64 kMaxErrorBurst = 4;

  AprMemCache(const ExternalClusterSpec& cluster, int thread_limit,
              Hasher* hasher, Statistics* statistics, Timer* timer,
              MessageHandler* handler);
  ~AprMemCache();

  static void InitStats(Statistics* statistics);

  const ExternalClusterSpec& cluster_spec() const { return cluster_spec_; }

  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);

  bool Connect();

  bool valid_server_spec() const { return valid_server_spec_; }

  bool GetStatus(GoogleString* status_string);

  static GoogleString FormatName() { return "AprMemCache"; }
  virtual GoogleString Name() const { return FormatName(); }

  virtual bool IsBlocking() const { return true; }

  void RecordError();

  virtual bool IsHealthy() const;

  virtual void ShutDown();

  virtual bool MustEncodeKeyInValueOnPut() const { return true; }
  virtual void PutWithKeyInValue(const GoogleString& key,
                                 const SharedString& key_and_value);

  void set_timeout_us(int timeout_us);

 private:
  void DecodeValueMatchingKeyAndCallCallback(
      const GoogleString& key, const char* data, size_t data_len,
      const char* calling_method, Callback* callback);

  void PutHelper(const GoogleString& key, const SharedString& key_and_value);

  ExternalClusterSpec cluster_spec_;
  bool valid_server_spec_;
  int thread_limit_;
  int timeout_us_;
  apr_pool_t* pool_;
  apr_memcache2_t* memcached_;
  std::vector<apr_memcache2_server_t*> servers_;
  Hasher* hasher_;
  Timer* timer_;
  AtomicBool shutdown_;

  Variable* timeouts_;
  UpDownCounter* last_error_checkpoint_ms_;
  UpDownCounter* error_burst_size_;

  MessageHandler* message_handler_;

  Variable* last_apr_error_;

  
};

}  

#endif