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
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
#include "base/thread_pool_delayed.hpp"
#include <array>
using namespace std;
namespace base
{
namespace thread_pool
{
namespace delayed
{
ThreadPool::ThreadPool(size_t threadsCount /* = 1 */, Exit e /* = Exit::SkipPending */)
: m_exit(e)
{
for (size_t i = 0; i < threadsCount; ++i)
m_threads.emplace_back(threads::SimpleThread(&ThreadPool::ProcessTasks, this));
}
ThreadPool::~ThreadPool()
{
ShutdownAndJoin();
}
bool ThreadPool::Push(Task && t)
{
return TouchQueues([&]() { m_immediate.emplace(move(t)); });
}
bool ThreadPool::Push(Task const & t)
{
return TouchQueues([&]() { m_immediate.emplace(t); });
}
bool ThreadPool::PushDelayed(Duration const & delay, Task && t)
{
auto const when = Now() + delay;
return TouchQueues([&]() { m_delayed.emplace(when, move(t)); });
}
bool ThreadPool::PushDelayed(Duration const & delay, Task const & t)
{
auto const when = Now() + delay;
return TouchQueues([&]() { m_delayed.emplace(when, t); });
}
void ThreadPool::ProcessTasks()
{
ImmediateQueue pendingImmediate;
DelayedQueue pendingDelayed;
while (true)
{
array<Task, QUEUE_TYPE_COUNT> tasks;
{
unique_lock<mutex> lk(m_mu);
if (!m_delayed.empty())
{
// We need to wait until the moment when the earliest delayed
// task may be executed, given that an immediate task or a
// delayed task with an earlier execution time may arrive
// while we are waiting.
auto const when = m_delayed.top().m_when;
m_cv.wait_until(lk, when, [this, when]() {
return m_shutdown || !m_immediate.empty() || m_delayed.empty() ||
(!m_delayed.empty() && m_delayed.top().m_when < when);
});
}
else
{
// When there are no delayed tasks in the queue, we need to
// wait until there is at least one immediate or delayed task.
m_cv.wait(lk,
[this]() { return m_shutdown || !m_immediate.empty() || !m_delayed.empty(); });
}
if (m_shutdown)
{
switch (m_exit)
{
case Exit::ExecPending:
ASSERT(pendingImmediate.empty(), ());
m_immediate.swap(pendingImmediate);
ASSERT(pendingDelayed.empty(), ());
m_delayed.swap(pendingDelayed);
break;
case Exit::SkipPending: break;
}
break;
}
auto const canExecImmediate = !m_immediate.empty();
auto const canExecDelayed = !m_delayed.empty() && Now() >= m_delayed.top().m_when;
if (canExecImmediate)
{
tasks[QUEUE_TYPE_IMMEDIATE] = move(m_immediate.front());
m_immediate.pop();
}
if (canExecDelayed)
{
tasks[QUEUE_TYPE_DELAYED] = move(m_delayed.top().m_task);
m_delayed.pop();
}
}
for (auto const & task : tasks)
{
if (task)
task();
}
}
for (; !pendingImmediate.empty(); pendingImmediate.pop())
pendingImmediate.front()();
for (; !pendingDelayed.empty(); pendingDelayed.pop())
{
auto const & top = pendingDelayed.top();
while (true)
{
auto const now = Now();
if (now >= top.m_when)
break;
auto const delay = top.m_when - now;
this_thread::sleep_for(delay);
}
ASSERT(Now() >= top.m_when, ());
top.m_task();
}
}
bool ThreadPool::Shutdown(Exit e)
{
lock_guard<mutex> lk(m_mu);
if (m_shutdown)
return false;
m_shutdown = true;
m_exit = e;
m_cv.notify_all();
return true;
}
void ThreadPool::ShutdownAndJoin()
{
ASSERT(m_checker.CalledOnOriginalThread(), ());
Shutdown(m_exit);
for (auto & thread : m_threads)
{
if (thread.joinable())
thread.join();
}
m_threads.clear();
}
} // namespace delayed
} // namespace thread_pool
} // namespace base
|
