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
|
// Copyright (c) 2015 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "scheduler.h"
#include <assert.h>
#include <boost/bind.hpp>
#include <boost/thread/reverse_lock.hpp>
#include <utility>
CScheduler::CScheduler() : nThreadsServicingQueue(0), stopRequested(false), stopWhenEmpty(false)
{
}
CScheduler::~CScheduler()
{
assert(nThreadsServicingQueue == 0);
}
#if BOOST_VERSION < 105000
static boost::system_time toPosixTime(const boost::chrono::system_clock::time_point& t)
{
return boost::posix_time::from_time_t(boost::chrono::system_clock::to_time_t(t));
}
#endif
void CScheduler::serviceQueue()
{
boost::unique_lock<boost::mutex> lock(newTaskMutex);
++nThreadsServicingQueue;
// newTaskMutex is locked throughout this loop EXCEPT
// when the thread is waiting or when the user's function
// is called.
while (!shouldStop()) {
try {
while (!shouldStop() && taskQueue.empty()) {
// Wait until there is something to do.
newTaskScheduled.wait(lock);
}
// Wait until either there is a new task, or until
// the time of the first item on the queue:
// wait_until needs boost 1.50 or later; older versions have timed_wait:
#if BOOST_VERSION < 105000
while (!shouldStop() && !taskQueue.empty() &&
newTaskScheduled.timed_wait(lock, toPosixTime(taskQueue.begin()->first))) {
// Keep waiting until timeout
}
#else
// Some boost versions have a conflicting overload of wait_until that returns void.
// Explicitly use a template here to avoid hitting that overload.
while (!shouldStop() && !taskQueue.empty() &&
newTaskScheduled.wait_until<>(lock, taskQueue.begin()->first) != boost::cv_status::timeout) {
// Keep waiting until timeout
}
#endif
// If there are multiple threads, the queue can empty while we're waiting (another
// thread may service the task we were waiting on).
if (shouldStop() || taskQueue.empty())
continue;
Function f = taskQueue.begin()->second;
taskQueue.erase(taskQueue.begin());
{
// Unlock before calling f, so it can reschedule itself or another task
// without deadlocking:
boost::reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
f();
}
} catch (...) {
--nThreadsServicingQueue;
throw;
}
}
--nThreadsServicingQueue;
}
void CScheduler::stop(bool drain)
{
{
boost::unique_lock<boost::mutex> lock(newTaskMutex);
if (drain)
stopWhenEmpty = true;
else
stopRequested = true;
}
newTaskScheduled.notify_all();
}
void CScheduler::schedule(CScheduler::Function f, boost::chrono::system_clock::time_point t)
{
{
boost::unique_lock<boost::mutex> lock(newTaskMutex);
taskQueue.insert(std::make_pair(t, f));
}
newTaskScheduled.notify_one();
}
void CScheduler::scheduleFromNow(CScheduler::Function f, int64_t deltaSeconds)
{
schedule(f, boost::chrono::system_clock::now() + boost::chrono::seconds(deltaSeconds));
}
static void Repeat(CScheduler* s, CScheduler::Function f, int64_t deltaSeconds)
{
f();
s->scheduleFromNow(boost::bind(&Repeat, s, f, deltaSeconds), deltaSeconds);
}
void CScheduler::scheduleEvery(CScheduler::Function f, int64_t deltaSeconds)
{
scheduleFromNow(boost::bind(&Repeat, this, f, deltaSeconds), deltaSeconds);
}
size_t CScheduler::getQueueInfo(boost::chrono::system_clock::time_point &first,
boost::chrono::system_clock::time_point &last) const
{
boost::unique_lock<boost::mutex> lock(newTaskMutex);
size_t result = taskQueue.size();
if (!taskQueue.empty()) {
first = taskQueue.begin()->first;
last = taskQueue.rbegin()->first;
}
return result;
}
|
