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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "barrier.h"
     18 
     19 #include "base/mutex.h"
     20 #include "thread.h"
     21 
     22 namespace art {
     23 
     24 Barrier::Barrier(int count)
     25     : count_(count),
     26       lock_("GC barrier lock"),
     27       condition_("GC barrier condition", lock_) {
     28 }
     29 
     30 void Barrier::Pass(Thread* self) {
     31   MutexLock mu(self, lock_);
     32   SetCountLocked(self, count_ - 1);
     33 }
     34 
     35 void Barrier::Wait(Thread* self) {
     36   Increment(self, -1);
     37 }
     38 
     39 void Barrier::Init(Thread* self, int count) {
     40   MutexLock mu(self, lock_);
     41   SetCountLocked(self, count);
     42 }
     43 
     44 void Barrier::Increment(Thread* self, int delta) {
     45   MutexLock mu(self, lock_);
     46   SetCountLocked(self, count_ + delta);
     47   if (count_ != 0) {
     48     condition_.Wait(self);
     49   }
     50 }
     51 
     52 void Barrier::SetCountLocked(Thread* self, int count) {
     53   count_ = count;
     54   if (count_ == 0) {
     55     condition_.Broadcast(self);
     56   }
     57 }
     58 
     59 Barrier::~Barrier() {
     60   CHECK(!count_) << "Attempted to destroy barrier with non zero count";
     61 }
     62 
     63 }  // namespace art
     64