rate_controller.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 NET_INSTAWEB_HTTP_PUBLIC_RATE_CONTROLLER_H_
#define NET_INSTAWEB_HTTP_PUBLIC_RATE_CONTROLLER_H_

#include <map>

#include "pagespeed/kernel/base/atomic_bool.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/ref_counted_ptr.h"
#include "pagespeed/kernel/base/scoped_ptr.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/thread_annotations.h"

namespace net_instaweb {

class AbstractMutex;
class AsyncFetch;
class MessageHandler;
class Statistics;
class ThreadSystem;
class TimedVariable;
class UpDownCounter;
class UrlAsyncFetcher;

class RateController {
 public:
  static const char kQueuedFetchCount[];
  static const char kDroppedFetchCount[];
  static const char kCurrentGlobalFetchQueueSize[];

  RateController(int max_global_queue_size,
                 int per_host_outgoing_request_threshold,
                 int per_host_queued_request_threshold,
                 ThreadSystem* thread_system,
                 Statistics* statistics);

  virtual ~RateController();

  void ShutDown() { shutdown_.set_value(true); }
  bool is_shut_down() const { return shutdown_.value(); }

  void Fetch(UrlAsyncFetcher* fetcher,
             const GoogleString& url,
             MessageHandler* message_handler,
             AsyncFetch* fetch);

  static void InitStats(Statistics* statistics);

 private:
  class HostFetchInfo;
  class CustomFetch;
  friend class CustomFetch;

  typedef RefCountedPtr<HostFetchInfo> HostFetchInfoPtr;

  typedef std::map<GoogleString, HostFetchInfoPtr*> HostFetchInfoMap;

  void DeleteFetchInfoIfPossible(const HostFetchInfoPtr& fetch_info);

  const int max_global_queue_size_;
  const int per_host_outgoing_request_threshold_;
  const int per_host_queued_request_threshold_;
  ThreadSystem* thread_system_;

  HostFetchInfoMap fetch_info_map_ GUARDED_BY(mutex_);
  scoped_ptr<AbstractMutex> mutex_;

  TimedVariable* queued_fetch_count_;
  TimedVariable* dropped_fetch_count_;
  UpDownCounter* current_global_fetch_queue_size_;

  AtomicBool shutdown_;

  
};

}  

#endif