tvl-depot/absl/synchronization/internal/thread_pool.h
Abseil Team 018b4db1d7 Export of internal Abseil changes.
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fd86c60bac6c41f1629ce1ab7dc1c8edff398a59 by Alex Strelnikov <strel@google.com>:

Import PR: https://github.com/abseil/abseil-cpp/pull/243
Fix Windows ARM64 intrinsic use.

PiperOrigin-RevId: 228535649

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a0ca663f606a3b31493683e405be2b1cff450894 by CJ Johnson <johnsoncj@google.com>:

Fixes issue of mixed signedness comparison

PiperOrigin-RevId: 228535623

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d71aaa1705d7303b43fe02088fe07b153e647796 by Shaindel Schwartz <shaindel@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 228534365

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c1b49d361aa880198e071f93997724bddbcd4760 by Samuel Benzaquen <sbenza@google.com>:

Internal cleanup

PiperOrigin-RevId: 228406627

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0c4b1c2bed107698e209055b3431771d7a1bdba1 by Dave Walker <dawalker@google.com>:

Add comments about the purpose of container_internal::slot_type.

PiperOrigin-RevId: 228264537

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060aa6077d2f3a0a129149e0644d19f2f521b241 by Abseil Team <absl-team@google.com>:

#include <cmath> in hashtablez_sampler.cc

Expected to fix the android build.

PiperOrigin-RevId: 228222550
GitOrigin-RevId: fd86c60bac6c41f1629ce1ab7dc1c8edff398a59
Change-Id: I26339fd4548c1a81b037cb52c26910d1bd850ea8
2019-01-09 13:09:28 -05:00

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2.4 KiB
C++

// 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
//
// http://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 {
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 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_ GUARDED_BY(mu_);
std::vector<std::thread> threads_;
};
} // namespace synchronization_internal
} // namespace absl
#endif // ABSL_SYNCHRONIZATION_INTERNAL_THREAD_POOL_H_