1// Copyright (c) 2024-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5#ifndef BITCOIN_UTIL_TASK_RUNNER_H
6#define BITCOIN_UTIL_TASK_RUNNER_H
7
8#include <cstddef>
9#include <functional>
10
11namespace util {
12
13/** @file
14 * This header provides an interface and simple implementation for a task
15 * runner. Another threaded, serial implementation using a queue is available in
16 * the scheduler module's SerialTaskRunner.
17 */
18
19class TaskRunnerInterface
20{
21public:
22    virtual ~TaskRunnerInterface() = default;
23
24    /**
25     * The callback can either be queued for later/asynchronous/threaded
26     * processing, or be executed immediately for synchronous processing.
27     */
28
29    virtual void insert(std::function<void()> func) = 0;
30
31    /**
32     * Forces the processing of all pending events.
33     */
34    virtual void flush() = 0;
35
36    /**
37     * Returns the number of currently pending events.
38     */
39    virtual size_t size() = 0;
40};
41
42class ImmediateTaskRunner : public TaskRunnerInterface
43{
44public:
45    void insert(std::function<void()> func) override { func(); }
46    void flush() override {}
47    size_t size() override { return 0; }
48};
49
50} // namespace util
51
52#endif // BITCOIN_UTIL_TASK_RUNNER_H
53