blob: fa572f04f876ad831bf6bcb618b4877526e506c2 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
// Copyright 2017 The Abseil Authors.
//
// 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
//
// https://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.
#include "absl/synchronization/barrier.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/synchronization/mutex.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
// Return whether int *arg is zero.
static bool IsZero(void *arg) {
return 0 == *reinterpret_cast<int *>(arg);
}
bool Barrier::Block() {
MutexLock l(&this->lock_);
this->num_to_block_--;
if (this->num_to_block_ < 0) {
ABSL_RAW_LOG(
FATAL,
"Block() called too many times. num_to_block_=%d out of total=%d",
this->num_to_block_, this->num_to_exit_);
}
this->lock_.Await(Condition(IsZero, &this->num_to_block_));
// Determine which thread can safely delete this Barrier object
this->num_to_exit_--;
ABSL_RAW_CHECK(this->num_to_exit_ >= 0, "barrier underflow");
// If num_to_exit_ == 0 then all other threads in the barrier have
// exited the Wait() and have released the Mutex so this thread is
// free to delete the barrier.
return this->num_to_exit_ == 0;
}
ABSL_NAMESPACE_END
} // namespace absl
|
