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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
|
#pragma once
#include <deque>
#include <type_traits>
#include <atomic>
#include <condition_variable>
#include <mutex>
#include <optional>
#include <base/MoveOrCopyIfThrow.h>
/** A very simple thread-safe queue of limited size.
* If you try to pop an item from an empty queue, the thread is blocked until the queue becomes nonempty or queue is finished.
* If you try to push an element into an overflowed queue, the thread is blocked until space appears in the queue or queue is finished.
*/
template <typename T>
class ConcurrentBoundedQueue
{
private:
using Container = std::deque<T>;
Container queue;
mutable std::mutex queue_mutex;
std::condition_variable push_condition;
std::condition_variable pop_condition;
bool is_finished = false;
size_t max_fill = 0;
template <bool back, typename ... Args>
bool emplaceImpl(std::optional<UInt64> timeout_milliseconds, Args &&...args)
{
{
std::unique_lock<std::mutex> queue_lock(queue_mutex);
auto predicate = [&]() { return is_finished || queue.size() < max_fill; };
if (timeout_milliseconds.has_value())
{
bool wait_result = push_condition.wait_for(queue_lock, std::chrono::milliseconds(timeout_milliseconds.value()), predicate);
if (!wait_result)
return false;
}
else
{
push_condition.wait(queue_lock, predicate);
}
if (is_finished)
return false;
if constexpr (back)
queue.emplace_back(std::forward<Args>(args)...);
else
queue.emplace_front(std::forward<Args>(args)...);
}
pop_condition.notify_one();
return true;
}
template <bool front>
bool popImpl(T & x, std::optional<UInt64> timeout_milliseconds)
{
{
std::unique_lock<std::mutex> queue_lock(queue_mutex);
auto predicate = [&]() { return is_finished || !queue.empty(); };
if (timeout_milliseconds.has_value())
{
bool wait_result = pop_condition.wait_for(queue_lock, std::chrono::milliseconds(timeout_milliseconds.value()), predicate);
if (!wait_result)
return false;
}
else
{
pop_condition.wait(queue_lock, predicate);
}
if (is_finished && queue.empty())
return false;
if constexpr (front)
{
detail::moveOrCopyIfThrow(std::move(queue.front()), x);
queue.pop_front();
}
else
{
detail::moveOrCopyIfThrow(std::move(queue.back()), x);
queue.pop_back();
}
}
push_condition.notify_one();
return true;
}
public:
explicit ConcurrentBoundedQueue(size_t max_fill_)
: max_fill(max_fill_)
{}
/// Returns false if queue is finished
[[nodiscard]] bool pushFront(const T & x)
{
return emplaceImpl</* back= */ false>(/* timeout_milliseconds= */ std::nullopt, x);
}
/// Returns false if queue is finished
[[nodiscard]] bool push(const T & x)
{
return emplace(x);
}
[[nodiscard]] bool push(T && x)
{
return emplace(std::move(x));
}
/// Returns false if queue is finished
template <typename... Args>
[[nodiscard]] bool emplace(Args &&... args)
{
return emplaceImpl</* back= */ true>(std::nullopt /* timeout in milliseconds */, std::forward<Args>(args)...);
}
/// Returns false if queue is finished or object was not pushed during timeout
[[nodiscard]] bool tryPush(const T & x, UInt64 milliseconds = 0)
{
return emplaceImpl</* back= */ true>(milliseconds, x);
}
[[nodiscard]] bool tryPush(T && x, UInt64 milliseconds = 0)
{
return emplaceImpl</* back= */ true>(milliseconds, std::move(x));
}
/// Returns false if queue is finished or object was not emplaced during timeout
template <typename... Args>
[[nodiscard]] bool tryEmplace(UInt64 milliseconds, Args &&... args)
{
return emplaceImpl</* back= */ true>(milliseconds, std::forward<Args>(args)...);
}
/// Returns false if queue is finished and empty
[[nodiscard]] bool pop(T & x)
{
return popImpl</* front= */ true>(x, std::nullopt /*timeout in milliseconds*/);
}
/// Returns false if queue is (finished and empty) or (object was not popped during timeout)
[[nodiscard]] bool tryPop(T & x, UInt64 milliseconds)
{
return popImpl</* front= */ true>(x, milliseconds);
}
/// Returns false if queue is empty.
[[nodiscard]] bool tryPop(T & x)
{
// we don't use popImpl to avoid CV wait
{
std::lock_guard queue_lock(queue_mutex);
if (queue.empty())
return false;
detail::moveOrCopyIfThrow(std::move(queue.front()), x);
queue.pop_front();
}
push_condition.notify_one();
return true;
}
/// Returns size of queue
size_t size() const
{
std::lock_guard lock(queue_mutex);
return queue.size();
}
/// Returns if queue is empty
bool empty() const
{
std::lock_guard lock(queue_mutex);
return queue.empty();
}
/** Clear and finish queue
* After that push operation will return false
* pop operations will return values until queue become empty
* Returns true if queue was already finished
*/
bool finish()
{
bool was_finished_before = false;
{
std::lock_guard lock(queue_mutex);
if (is_finished)
return true;
was_finished_before = is_finished;
is_finished = true;
}
pop_condition.notify_all();
push_condition.notify_all();
return was_finished_before;
}
/// Returns if queue is finished
bool isFinished() const
{
std::lock_guard lock(queue_mutex);
return is_finished;
}
/// Returns if queue is finished and empty
bool isFinishedAndEmpty() const
{
std::lock_guard lock(queue_mutex);
return is_finished && queue.empty();
}
/// Clear queue
void clear()
{
{
std::lock_guard lock(queue_mutex);
if (is_finished)
return;
Container empty_queue;
queue.swap(empty_queue);
}
push_condition.notify_all();
}
/// Clear and finish queue
void clearAndFinish()
{
{
std::lock_guard lock(queue_mutex);
Container empty_queue;
queue.swap(empty_queue);
is_finished = true;
}
pop_condition.notify_all();
push_condition.notify_all();
}
};
|
