1/*
2 * Copyright 2017-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <folly/Executor.h>
20
21namespace folly {
22class EventBase;
23} // namespace folly
24
25namespace folly {
26
27// An IOExecutor is an executor that operates on at least one EventBase. One of
28// these EventBases should be accessible via getEventBase(). The event base
29// returned by a call to getEventBase() is implementation dependent.
30//
31// Note that IOExecutors don't necessarily loop on the base themselves - for
32// instance, EventBase itself is an IOExecutor but doesn't drive itself.
33//
34// Implementations of IOExecutor are eligible to become the global IO executor,
35// returned on every call to getIOExecutor(), via setIOExecutor().
36// These functions are declared in GlobalExecutor.h
37//
38// If getIOExecutor is called and none has been set, a default global
39// IOThreadPoolExecutor will be created and returned.
40class IOExecutor : public virtual folly::Executor {
41 public:
42 ~IOExecutor() override = default;
43 virtual folly::EventBase* getEventBase() = 0;
44};
45
46} // namespace folly
47