barrier.cc
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1 // Copyright 2017 The Abseil Authors.
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 // https://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 
16 
19 
20 namespace absl {
21 
22 // Return whether int *arg is zero.
23 static bool IsZero(void *arg) {
24  return 0 == *reinterpret_cast<int *>(arg);
25 }
26 
28  MutexLock l(&this->lock_);
29 
30  this->num_to_block_--;
31  if (this->num_to_block_ < 0) {
33  FATAL,
34  "Block() called too many times. num_to_block_=%d out of total=%d",
35  this->num_to_block_, this->num_to_exit_);
36  }
37 
38  this->lock_.Await(Condition(IsZero, &this->num_to_block_));
39 
40  // Determine which thread can safely delete this Barrier object
41  this->num_to_exit_--;
42  ABSL_RAW_CHECK(this->num_to_exit_ >= 0, "barrier underflow");
43 
44  // If num_to_exit_ == 0 then all other threads in the barrier have
45  // exited the Wait() and have released the Mutex so this thread is
46  // free to delete the barrier.
47  return this->num_to_exit_ == 0;
48 }
49 
50 } // namespace absl
static bool IsZero(void *arg)
Definition: barrier.cc:23
#define ABSL_RAW_LOG(severity,...)
Definition: raw_logging.h:42
Definition: algorithm.h:29
bool Block()
Definition: barrier.cc:27
Mutex lock_
Definition: barrier.h:71
#define ABSL_RAW_CHECK(condition, message)
Definition: raw_logging.h:57
void * arg
Definition: mutex.cc:292
void Await(const Condition &cond)


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autogenerated on Mon Feb 28 2022 21:31:17