1/*
2 * Copyright 2018-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#include <folly/executors/TimekeeperScheduledExecutor.h>
18#include <folly/futures/Future.h>
19
20namespace folly {
21
22/* static */ Executor::KeepAlive<TimekeeperScheduledExecutor>
23TimekeeperScheduledExecutor::create(
24 Executor::KeepAlive<> parent,
25 Function<std::shared_ptr<Timekeeper>()> getTimekeeper) {
26 return makeKeepAlive<TimekeeperScheduledExecutor>(
27 new TimekeeperScheduledExecutor(
28 std::move(parent), std::move(getTimekeeper)));
29}
30
31void TimekeeperScheduledExecutor::run(Func func) {
32 try {
33 func();
34 } catch (std::exception const& ex) {
35 LOG(ERROR) << "func threw unhandled exception " << folly::exceptionStr(ex);
36 } catch (...) {
37 LOG(ERROR) << "func threw unhandled non-exception object";
38 }
39}
40
41void TimekeeperScheduledExecutor::add(Func func) {
42 parent_->add(
43 [keepAlive = getKeepAliveToken(this), f = std::move(func)]() mutable {
44 keepAlive->run(std::move(f));
45 });
46}
47
48void TimekeeperScheduledExecutor::scheduleAt(
49 Func&& func,
50 ScheduledExecutor::TimePoint const& t) {
51 auto delay = std::chrono::duration_cast<folly::Duration>(
52 t - std::chrono::steady_clock::now());
53 if (delay.count() > 0) {
54 auto tk = getTimekeeper_();
55 if (UNLIKELY(!tk)) {
56 throw TimekeeperScheduledExecutorNoTimekeeper();
57 }
58 tk->after(delay)
59 .via(parent_.copy())
60 .thenValue([keepAlive = getKeepAliveToken(this), f = std::move(func)](
61 auto&&) mutable { keepAlive->run(std::move(f)); });
62 } else {
63 add(std::move(func));
64 }
65}
66
67bool TimekeeperScheduledExecutor::keepAliveAcquire() {
68 auto keepAliveCounter =
69 keepAliveCounter_.fetch_add(1, std::memory_order_relaxed);
70 DCHECK(keepAliveCounter > 0);
71 return true;
72}
73
74void TimekeeperScheduledExecutor::keepAliveRelease() {
75 auto keepAliveCounter =
76 keepAliveCounter_.fetch_sub(1, std::memory_order_acq_rel);
77 DCHECK(keepAliveCounter > 0);
78 if (keepAliveCounter == 1) {
79 delete this;
80 }
81}
82
83} // namespace folly
84