1    :  // Copyright 2014 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  //
  15    :  // Utility functions for spending a fixed amount of time trying to acquire
  16    :  // a base::Lock (or any lock with the same API).
  17    :  
  18    :  #ifndef SYZYGY_AGENT_ASAN_TIMED_TRY_H_
  19    :  #define SYZYGY_AGENT_ASAN_TIMED_TRY_H_
  20    :  
  21    :  #include "base/time/time.h"
  22    :  
  23  m :  namespace agent {
  24  m :  namespace asan {
  25    :  
  26    :  // Spends at most |delta| time trying to acquire the given |lock|. The time
  27    :  // limit is a guideline and not precise. This function tries to grab the lock
  28    :  // by repeatedly calling 'LockType::Try' via LockTryFunctor.
  29    :  // @tparam LockType The type of the lock to be acquired.
  30    :  // @param delta The maximum amount of time to spend trying to acquire the lock.
  31    :  // @param lock The lock to be acquired.
  32    :  // @returns true if the lock has been acquired, false otherwise.
  33  m :  template<typename LockType>
  34  m :  bool TimedTry(base::TimeDelta delta, LockType* lock);
  35    :  
  36    :  // A scoped timed try lock.
  37    :  // @tparam LockType The type of the lock to be acquired.
  38  m :  template<typename LockType>
  39  m :  class AutoTimedTry {
  40  m :   public:
  41  m :    AutoTimedTry(base::TimeDelta delta, LockType* lock);
  42  m :    ~AutoTimedTry();
  43  m :    bool is_acquired() const;
  44    :  
  45  m :   private:
  46  m :    LockType* lock_;
  47  m :    bool is_acquired_;
  48    :  
  49  m :    DISALLOW_COPY_AND_ASSIGN(AutoTimedTry);
  50  m :  };
  51    :  
  52  m :  }  // namespace asan
  53  m :  }  // namespace agent
  54    :  
  55    :  #include "syzygy/agent/asan/timed_try_impl.h"
  56    :  
  57    :  #endif  // SYZYGY_AGENT_ASAN_TIMED_TRY_H_