blob: 0cb96dacde831f0a4936da2f16cd07e3910c3c19 (
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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
// 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.
#ifndef ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
#define ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
#include <cassert>
#include <cstddef>
#include <functional>
#include <queue>
#include <thread> // NOLINT(build/c++11)
#include <vector>
#include "absl/base/thread_annotations.h"
#include "absl/synchronization/mutex.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace synchronization_internal {
// A simple ThreadPool implementation for tests.
class ThreadPool {
public:
explicit ThreadPool(int num_threads) {
for (int i = 0; i < num_threads; ++i) {
threads_.push_back(std::thread(&ThreadPool::WorkLoop, this));
}
}
ThreadPool(const ThreadPool &) = delete;
ThreadPool &operator=(const ThreadPool &) = delete;
~ThreadPool() {
{
absl::MutexLock l(&mu_);
for (size_t i = 0; i < threads_.size(); i++) {
queue_.push(nullptr); // Shutdown signal.
}
}
for (auto &t : threads_) {
t.join();
}
}
// Schedule a function to be run on a ThreadPool thread immediately.
void Schedule(std::function<void()> func) {
assert(func != nullptr);
absl::MutexLock l(&mu_);
queue_.push(std::move(func));
}
private:
bool WorkAvailable() const ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu_) {
return !queue_.empty();
}
void WorkLoop() {
while (true) {
std::function<void()> func;
{
absl::MutexLock l(&mu_);
mu_.Await(absl::Condition(this, &ThreadPool::WorkAvailable));
func = std::move(queue_.front());
queue_.pop();
}
if (func == nullptr) { // Shutdown signal.
break;
}
func();
}
}
absl::Mutex mu_;
std::queue<std::function<void()>> queue_ ABSL_GUARDED_BY(mu_);
std::vector<std::thread> threads_;
};
} // namespace synchronization_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_
|
