78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
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// Copyright 2018 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/task/task_executor.h"
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#include <type_traits>
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#include "base/no_destructor.h"
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#include "base/task/task_traits.h"
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#include "base/task/task_traits_extension.h"
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#include "base/threading/thread_local.h"
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namespace base {
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namespace {
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// Maps TaskTraits extension IDs to registered TaskExecutors. Index |n|
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// corresponds to id |n - 1|.
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using TaskExecutorMap =
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std::array<TaskExecutor*, TaskTraitsExtensionStorage::kMaxExtensionId>;
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TaskExecutorMap* GetTaskExecutorMap() {
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static_assert(std::is_trivially_destructible<TaskExecutorMap>::value,
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"TaskExecutorMap not trivially destructible");
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static TaskExecutorMap executors{};
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return &executors;
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}
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static_assert(
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TaskTraitsExtensionStorage::kInvalidExtensionId == 0,
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"TaskExecutorMap depends on 0 being an invalid TaskTraits extension ID");
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} // namespace
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ThreadLocalPointer<TaskExecutor>* GetTLSForCurrentTaskExecutor() {
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static NoDestructor<ThreadLocalPointer<TaskExecutor>> instance;
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return instance.get();
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}
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void SetTaskExecutorForCurrentThread(TaskExecutor* task_executor) {
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DCHECK(!task_executor || !GetTLSForCurrentTaskExecutor()->Get() ||
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GetTLSForCurrentTaskExecutor()->Get() == task_executor);
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GetTLSForCurrentTaskExecutor()->Set(task_executor);
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}
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TaskExecutor* GetTaskExecutorForCurrentThread() {
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return GetTLSForCurrentTaskExecutor()->Get();
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}
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void RegisterTaskExecutor(uint8_t extension_id, TaskExecutor* task_executor) {
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DCHECK_NE(extension_id, TaskTraitsExtensionStorage::kInvalidExtensionId);
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DCHECK_LE(extension_id, TaskTraitsExtensionStorage::kMaxExtensionId);
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DCHECK_EQ((*GetTaskExecutorMap())[extension_id - 1], nullptr);
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(*GetTaskExecutorMap())[extension_id - 1] = task_executor;
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}
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void UnregisterTaskExecutorForTesting(uint8_t extension_id) {
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DCHECK_NE(extension_id, TaskTraitsExtensionStorage::kInvalidExtensionId);
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DCHECK_LE(extension_id, TaskTraitsExtensionStorage::kMaxExtensionId);
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DCHECK_NE((*GetTaskExecutorMap())[extension_id - 1], nullptr);
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(*GetTaskExecutorMap())[extension_id - 1] = nullptr;
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}
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TaskExecutor* GetRegisteredTaskExecutorForTraits(const TaskTraits& traits) {
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uint8_t extension_id = traits.extension_id();
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if (extension_id != TaskTraitsExtensionStorage::kInvalidExtensionId) {
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TaskExecutor* executor = (*GetTaskExecutorMap())[extension_id - 1];
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DCHECK(executor);
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return executor;
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}
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return nullptr;
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}
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} // namespace base
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