128 lines
4.2 KiB
C++
128 lines
4.2 KiB
C++
// Copyright 2017 The Chromium Authors
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#include "base/task/lazy_thread_pool_task_runner.h"
|
|
|
|
#include <atomic>
|
|
#include <utility>
|
|
|
|
#include "base/check_op.h"
|
|
#include "base/lazy_instance_helpers.h"
|
|
#include "base/task/thread_pool.h"
|
|
#include "build/build_config.h"
|
|
|
|
namespace base {
|
|
namespace internal {
|
|
|
|
namespace {
|
|
ScopedLazyTaskRunnerListForTesting* g_scoped_lazy_task_runner_list_for_testing =
|
|
nullptr;
|
|
} // namespace
|
|
|
|
template <typename TaskRunnerType, bool com_sta>
|
|
void LazyThreadPoolTaskRunner<TaskRunnerType, com_sta>::Reset() {
|
|
uintptr_t state = state_.load(std::memory_order_acquire);
|
|
|
|
DCHECK_NE(state, kLazyInstanceStateCreating) << "Race: all threads should be "
|
|
"unwound in unittests before "
|
|
"resetting TaskRunners.";
|
|
|
|
// Return if no reference is held by this instance.
|
|
if (!state)
|
|
return;
|
|
|
|
// Release the reference acquired in Get().
|
|
SequencedTaskRunner* task_runner = reinterpret_cast<TaskRunnerType*>(state);
|
|
task_runner->Release();
|
|
|
|
// Clear the state.
|
|
state_.store(0, std::memory_order_relaxed);
|
|
}
|
|
|
|
template <>
|
|
scoped_refptr<SequencedTaskRunner>
|
|
LazyThreadPoolTaskRunner<SequencedTaskRunner, false>::Create() {
|
|
// It is invalid to specify a SingleThreadTaskRunnerThreadMode with a
|
|
// LazyThreadPoolSequencedTaskRunner.
|
|
DCHECK_EQ(thread_mode_, SingleThreadTaskRunnerThreadMode::SHARED);
|
|
|
|
return ThreadPool::CreateSequencedTaskRunner(traits_);
|
|
}
|
|
|
|
template <>
|
|
scoped_refptr<SingleThreadTaskRunner>
|
|
LazyThreadPoolTaskRunner<SingleThreadTaskRunner, false>::Create() {
|
|
return ThreadPool::CreateSingleThreadTaskRunner(traits_, thread_mode_);
|
|
}
|
|
|
|
#if BUILDFLAG(IS_WIN)
|
|
template <>
|
|
scoped_refptr<SingleThreadTaskRunner>
|
|
LazyThreadPoolTaskRunner<SingleThreadTaskRunner, true>::Create() {
|
|
return ThreadPool::CreateCOMSTATaskRunner(traits_, thread_mode_);
|
|
}
|
|
#endif
|
|
|
|
// static
|
|
template <typename TaskRunnerType, bool com_sta>
|
|
TaskRunnerType* LazyThreadPoolTaskRunner<TaskRunnerType, com_sta>::CreateRaw(
|
|
void* void_self) {
|
|
auto self =
|
|
reinterpret_cast<LazyThreadPoolTaskRunner<TaskRunnerType, com_sta>*>(
|
|
void_self);
|
|
|
|
scoped_refptr<TaskRunnerType> task_runner = self->Create();
|
|
|
|
// Acquire a reference to the TaskRunner. The reference will either
|
|
// never be released or be released in Reset(). The reference is not
|
|
// managed by a scoped_refptr because adding a scoped_refptr member to
|
|
// LazyThreadPoolTaskRunner would prevent its static initialization.
|
|
task_runner->AddRef();
|
|
|
|
// Reset this instance when the current
|
|
// ScopedLazyTaskRunnerListForTesting is destroyed, if any.
|
|
if (g_scoped_lazy_task_runner_list_for_testing) {
|
|
g_scoped_lazy_task_runner_list_for_testing->AddCallback(
|
|
BindOnce(&LazyThreadPoolTaskRunner<TaskRunnerType, com_sta>::Reset,
|
|
Unretained(self)));
|
|
}
|
|
|
|
return task_runner.get();
|
|
}
|
|
|
|
template <typename TaskRunnerType, bool com_sta>
|
|
scoped_refptr<TaskRunnerType>
|
|
LazyThreadPoolTaskRunner<TaskRunnerType, com_sta>::Get() {
|
|
return WrapRefCounted(subtle::GetOrCreateLazyPointer(
|
|
state_, &LazyThreadPoolTaskRunner<TaskRunnerType, com_sta>::CreateRaw,
|
|
reinterpret_cast<void*>(this), nullptr, nullptr));
|
|
}
|
|
|
|
template class LazyThreadPoolTaskRunner<SequencedTaskRunner, false>;
|
|
template class LazyThreadPoolTaskRunner<SingleThreadTaskRunner, false>;
|
|
|
|
#if BUILDFLAG(IS_WIN)
|
|
template class LazyThreadPoolTaskRunner<SingleThreadTaskRunner, true>;
|
|
#endif
|
|
|
|
ScopedLazyTaskRunnerListForTesting::ScopedLazyTaskRunnerListForTesting() {
|
|
DCHECK(!g_scoped_lazy_task_runner_list_for_testing);
|
|
g_scoped_lazy_task_runner_list_for_testing = this;
|
|
}
|
|
|
|
ScopedLazyTaskRunnerListForTesting::~ScopedLazyTaskRunnerListForTesting() {
|
|
internal::CheckedAutoLock auto_lock(lock_);
|
|
for (auto& callback : callbacks_)
|
|
std::move(callback).Run();
|
|
g_scoped_lazy_task_runner_list_for_testing = nullptr;
|
|
}
|
|
|
|
void ScopedLazyTaskRunnerListForTesting::AddCallback(OnceClosure callback) {
|
|
internal::CheckedAutoLock auto_lock(lock_);
|
|
callbacks_.push_back(std::move(callback));
|
|
}
|
|
|
|
} // namespace internal
|
|
} // namespace base
|