mem_lock_state.h

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/*
 * Copyright 2015 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_BASE_MEM_LOCK_STATE_H_
#define PAGESPEED_KERNEL_BASE_MEM_LOCK_STATE_H_

#include <set>

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

namespace net_instaweb {

class MemLock;
class MemLockManager;

class MemLockState {
 public:

  struct Comparator {
    bool operator()(const MemLock* a, const MemLock* b) const;
  };

  struct StealComparator {
    bool operator()(const MemLock* a, const MemLock* b) const;
  };

  typedef std::set<MemLock*, MemLockState::Comparator> WakeupOrderedLockSet;
  typedef std::set<MemLock*, MemLockState::StealComparator> StealOrderedLockSet;

  const GoogleString& name() const { return name_; }

  MemLock* CreateLock(int64 sequence);

  void RemoveLock(MemLock* lock); 

  void UnscheduleLock(MemLock* lock);

  void ScheduleLock(MemLock* lock);

  bool GrabLock(MemLock* lock);

  void Unlock();

  void StealLock(MemLock* lock);

  MemLockManager* manager() { return manager_; }

  bool IsHeldInOrderedSet(MemLock* lock) const;

  template<typename T>
  static int Compare(const T& a, const T& b) {
    if (a < b) {
      return -1;
    } else if (a > b) {
      return 1;
    }
    return 0;
  }

 private:
  friend class MemLockManager; 

  MemLockState(StringPiece name, MemLockManager* manager);
  ~MemLockState();

  void MemLockManagerDestroyed();

  void RescheduleLock(int64 held_lock_grant_time_ms, MemLock* lock);

  MemLock* current_owner_; 
  int64 lock_count_; 
  WakeupOrderedLockSet pending_locks_;
  StealOrderedLockSet pending_steals_;
  GoogleString name_;
  MemLockManager* manager_;
};

}  

#endif