blob: 3ded1d908853e5c64945c0cd6d2b6c8df7e30d03 [file] [log] [blame]
// 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.
#ifndef BASE_TASK_TASK_EXECUTOR_H_
#define BASE_TASK_TASK_EXECUTOR_H_
#include "base/base_export.h"
#include "base/memory/ref_counted.h"
#include "base/sequenced_task_runner.h"
#include "base/single_thread_task_runner.h"
#include "base/task/single_thread_task_runner_thread_mode.h"
#include "base/task_runner.h"
#include "build/build_config.h"
#include "starboard/types.h"
namespace base {
class Location;
class TaskTraits;
// A TaskExecutor can execute Tasks with a specific TaskTraits extension id. To
// handle Tasks posted via the //base/task/post_task.h API, the TaskExecutor
// should be registered by calling RegisterTaskExecutor().
class BASE_EXPORT TaskExecutor {
public:
virtual ~TaskExecutor() = default;
// Posts |task| with a |delay| and specific |traits|. |delay| can be zero. For
// one off tasks that don't require a TaskRunner. Returns false if the task
// definitely won't run because of current shutdown state.
virtual bool PostDelayedTaskWithTraits(const Location& from_here,
const TaskTraits& traits,
OnceClosure task,
TimeDelta delay) = 0;
// Returns a TaskRunner whose PostTask invocations result in scheduling tasks
// using |traits|. Tasks may run in any order and in parallel.
virtual scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
const TaskTraits& traits) = 0;
// Returns a SequencedTaskRunner whose PostTask invocations result in
// scheduling tasks using |traits|. Tasks run one at a time in posting order.
virtual scoped_refptr<SequencedTaskRunner>
CreateSequencedTaskRunnerWithTraits(const TaskTraits& traits) = 0;
// Returns a SingleThreadTaskRunner whose PostTask invocations result in
// scheduling tasks using |traits|. Tasks run on a single thread in posting
// order. If |traits| identifies an existing thread,
// SingleThreadTaskRunnerThreadMode::SHARED must be used.
virtual scoped_refptr<SingleThreadTaskRunner>
CreateSingleThreadTaskRunnerWithTraits(
const TaskTraits& traits,
SingleThreadTaskRunnerThreadMode thread_mode) = 0;
#if defined(OS_WIN)
// Returns a SingleThreadTaskRunner whose PostTask invocations result in
// scheduling tasks using |traits| in a COM Single-Threaded Apartment. Tasks
// run in the same Single-Threaded Apartment in posting order for the returned
// SingleThreadTaskRunner. If |traits| identifies an existing thread,
// SingleThreadTaskRunnerThreadMode::SHARED must be used.
virtual scoped_refptr<SingleThreadTaskRunner>
CreateCOMSTATaskRunnerWithTraits(
const TaskTraits& traits,
SingleThreadTaskRunnerThreadMode thread_mode) = 0;
#endif // defined(OS_WIN)
};
// Register a TaskExecutor with the //base/task/post_task.h API in the current
// process for tasks subsequently posted with a TaskTraits extension with the
// given |extension_id|. All executors need to be registered before any tasks
// are posted with |extension_id|. Only one executor per |extension_id| is
// supported.
void BASE_EXPORT RegisterTaskExecutor(uint8_t extension_id,
TaskExecutor* task_executor);
void BASE_EXPORT UnregisterTaskExecutorForTesting(uint8_t extension_id);
// Determines whether a registered TaskExecutor will handle tasks with the given
// |traits| and, if so, returns a pointer to it. Otherwise, returns |nullptr|.
TaskExecutor* GetRegisteredTaskExecutorForTraits(const TaskTraits& traits);
} // namespace base
#endif // BASE_TASK_TASK_EXECUTOR_H_