1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
// Copyright 2023 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include "pw_async_basic/dispatcher.h"
#include <mutex>
#include "pw_chrono/system_clock.h"
using namespace std::chrono_literals;
namespace pw::async {
BasicDispatcher::~BasicDispatcher() {
RequestStop();
lock_.lock();
DrainTaskQueue();
lock_.unlock();
}
void BasicDispatcher::Run() {
lock_.lock();
while (!stop_requested_) {
MaybeSleep();
ExecuteDueTasks();
}
DrainTaskQueue();
lock_.unlock();
}
void BasicDispatcher::RunUntilIdle() {
lock_.lock();
ExecuteDueTasks();
if (stop_requested_) {
DrainTaskQueue();
}
lock_.unlock();
}
void BasicDispatcher::RunUntil(chrono::SystemClock::time_point end_time) {
lock_.lock();
while (end_time < now() && !stop_requested_) {
MaybeSleep();
ExecuteDueTasks();
}
if (stop_requested_) {
DrainTaskQueue();
}
lock_.unlock();
}
void BasicDispatcher::RunFor(chrono::SystemClock::duration duration) {
RunUntil(now() + duration);
}
void BasicDispatcher::MaybeSleep() {
if (task_queue_.empty() || task_queue_.front().due_time_ > now()) {
// Sleep until a notification is received or until the due time of the
// next task. Notifications are sent when tasks are posted or 'stop' is
// requested.
std::optional<chrono::SystemClock::time_point> wake_time = std::nullopt;
if (!task_queue_.empty()) {
wake_time = task_queue_.front().due_time_;
}
lock_.unlock();
if (wake_time.has_value()) {
timed_notification_.try_acquire_until(*wake_time);
} else {
timed_notification_.acquire();
}
lock_.lock();
}
}
void BasicDispatcher::ExecuteDueTasks() {
while (!task_queue_.empty() && task_queue_.front().due_time_ <= now() &&
!stop_requested_) {
backend::NativeTask& task = task_queue_.front();
task_queue_.pop_front();
lock_.unlock();
Context ctx{this, &task.task_};
task(ctx, OkStatus());
lock_.lock();
}
}
void BasicDispatcher::RequestStop() {
{
std::lock_guard lock(lock_);
stop_requested_ = true;
}
timed_notification_.release();
}
void BasicDispatcher::DrainTaskQueue() {
while (!task_queue_.empty()) {
backend::NativeTask& task = task_queue_.front();
task_queue_.pop_front();
lock_.unlock();
Context ctx{this, &task.task_};
task(ctx, Status::Cancelled());
lock_.lock();
}
}
void BasicDispatcher::PostAt(Task& task, chrono::SystemClock::time_point time) {
PostTaskInternal(task.native_type(), time);
}
bool BasicDispatcher::Cancel(Task& task) {
std::lock_guard lock(lock_);
return task_queue_.remove(task.native_type());
}
void BasicDispatcher::PostTaskInternal(
backend::NativeTask& task, chrono::SystemClock::time_point time_due) {
lock_.lock();
task.due_time_ = time_due;
// Insert the new task in the queue after all tasks with the same or earlier
// deadline to ensure FIFO execution order.
auto it_front = task_queue_.begin();
auto it_behind = task_queue_.before_begin();
while (it_front != task_queue_.end() && time_due >= it_front->due_time_) {
++it_front;
++it_behind;
}
task_queue_.insert_after(it_behind, task);
lock_.unlock();
timed_notification_.release();
}
} // namespace pw::async
|
