summaryrefslogtreecommitdiff
path: root/src/lib/notifier.c
blob: cfd383d4be3bbe516b58949540e3dd32c8d1b883 (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
127
128
/*
 * Ouroboros - Copyright (C) 2016 - 2017
 *
 * Notifier event system using callbacks
 *
 *    Dimitri Staessens <dimitri.staessens@ugent.be>
 *    Sander Vrijders   <sander.vrijders@ugent.be>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * version 2.1 as published by the Free Software Foundation.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., http://www.fsf.org/about/contact/.
 */

#include <ouroboros/errno.h>
#include <ouroboros/notifier.h>
#include <ouroboros/list.h>

#include <pthread.h>
#include <stdlib.h>

struct listener {
        struct list_head next;
        notifier_fn_t    callback;
};

struct {
        struct list_head listeners;
        pthread_mutex_t  lock;
} notifier;

int notifier_init(void)
{
        if (pthread_mutex_init(&notifier.lock, NULL))
                return -1;

        list_head_init(&notifier.listeners);

        return 0;
}

void notifier_fini(void)
{
        struct list_head * p;
        struct list_head * h;

        pthread_mutex_lock(&notifier.lock);

        list_for_each_safe(p, h, &notifier.listeners) {
                struct listener * l = list_entry(p, struct listener, next);
                list_del(&l->next);
                free(l);
        }

        pthread_mutex_unlock(&notifier.lock);

        pthread_mutex_destroy(&notifier.lock);
}

void notifier_event(int          event,
                    const void * o)
{
        struct list_head * p;

        pthread_mutex_lock(&notifier.lock);

        list_for_each(p, &notifier.listeners)
                list_entry(p, struct listener, next)->callback(event, o);

        pthread_mutex_unlock(&notifier.lock);
}

int notifier_reg(notifier_fn_t callback)
{
        struct listener *  l;
        struct list_head * p;

        pthread_mutex_lock(&notifier.lock);

        list_for_each(p, &notifier.listeners) {
                struct listener * l = list_entry(p, struct listener, next);
                if (l->callback == callback) {
                        pthread_mutex_unlock(&notifier.lock);
                        return -EPERM;
                }
        }

        l = malloc(sizeof(*l));
        if (l == NULL) {
                pthread_mutex_unlock(&notifier.lock);
                return -ENOMEM;
        }

        l->callback = callback;

        list_add(&l->next, &notifier.listeners);

        pthread_mutex_unlock(&notifier.lock);

        return 0;
}

void notifier_unreg(notifier_fn_t callback)
{
        struct list_head * p;
        struct list_head * h;

        pthread_mutex_lock(&notifier.lock);

        list_for_each_safe(p, h, &notifier.listeners) {
                struct listener * l = list_entry(p, struct listener, next);
                if (l->callback == callback) {
                        list_del(&l->next);
                        free(l);
                        break;
                }
        }

        pthread_mutex_unlock(&notifier.lock);
}