Repo created

TMessagesProj/jni/voip/webrtc/base/task/task_executor.cc

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