aboutsummaryrefslogtreecommitdiff
path: root/primedev/thirdparty/spdlog/details/mpmc_blocking_q.h
blob: 5c3cca76bcad4641d1a198cd6329dc512c67e4c0 (plain)
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
// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

// multi producer-multi consumer blocking queue.
// enqueue(..) - will block until room found to put the new message.
// enqueue_nowait(..) - will return immediately with false if no room left in
// the queue.
// dequeue_for(..) - will block until the queue is not empty or timeout have
// passed.

#include <spdlog/details/circular_q.h>

#include <condition_variable>
#include <mutex>

namespace spdlog {
namespace details {

template<typename T>
class mpmc_blocking_queue
{
public:
    using item_type = T;
    explicit mpmc_blocking_queue(size_t max_items)
        : q_(max_items)
    {}

#ifndef __MINGW32__
    // try to enqueue and block if no room left
    void enqueue(T &&item)
    {
        {
            std::unique_lock<std::mutex> lock(queue_mutex_);
            pop_cv_.wait(lock, [this] { return !this->q_.full(); });
            q_.push_back(std::move(item));
        }
        push_cv_.notify_one();
    }

    // enqueue immediately. overrun oldest message in the queue if no room left.
    void enqueue_nowait(T &&item)
    {
        {
            std::unique_lock<std::mutex> lock(queue_mutex_);
            q_.push_back(std::move(item));
        }
        push_cv_.notify_one();
    }

    // try to dequeue item. if no item found. wait upto timeout and try again
    // Return true, if succeeded dequeue item, false otherwise
    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
    {
        {
            std::unique_lock<std::mutex> lock(queue_mutex_);
            if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
            {
                return false;
            }
            popped_item = std::move(q_.front());
            q_.pop_front();
        }
        pop_cv_.notify_one();
        return true;
    }

#else
    // apparently mingw deadlocks if the mutex is released before cv.notify_one(),
    // so release the mutex at the very end each function.

    // try to enqueue and block if no room left
    void enqueue(T &&item)
    {
        std::unique_lock<std::mutex> lock(queue_mutex_);
        pop_cv_.wait(lock, [this] { return !this->q_.full(); });
        q_.push_back(std::move(item));
        push_cv_.notify_one();
    }

    // enqueue immediately. overrun oldest message in the queue if no room left.
    void enqueue_nowait(T &&item)
    {
        std::unique_lock<std::mutex> lock(queue_mutex_);
        q_.push_back(std::move(item));
        push_cv_.notify_one();
    }

    // try to dequeue item. if no item found. wait upto timeout and try again
    // Return true, if succeeded dequeue item, false otherwise
    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
    {
        std::unique_lock<std::mutex> lock(queue_mutex_);
        if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
        {
            return false;
        }
        popped_item = std::move(q_.front());
        q_.pop_front();
        pop_cv_.notify_one();
        return true;
    }

#endif

    size_t overrun_counter()
    {
        std::unique_lock<std::mutex> lock(queue_mutex_);
        return q_.overrun_counter();
    }

    size_t size()
    {
        std::unique_lock<std::mutex> lock(queue_mutex_);
        return q_.size();
    }

private:
    std::mutex queue_mutex_;
    std::condition_variable push_cv_;
    std::condition_variable pop_cv_;
    spdlog::details::circular_q<T> q_;
};
} // namespace details
} // namespace spdlog