Atlas - SDL_eventwatch.c
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[FILE BEGIN]
1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#include "SDL_eventwatch_c.h"
24
25
26bool SDL_InitEventWatchList(SDL_EventWatchList *list)
27{
28    if (list->lock == NULL) {
29        list->lock = SDL_CreateMutex();
30        if (list->lock == NULL) {
31            return false;
32        }
33    }
34    return true;
35}
36
37void SDL_QuitEventWatchList(SDL_EventWatchList *list)
38{
39    if (list->lock) {
40        SDL_DestroyMutex(list->lock);
41        list->lock = NULL;
42    }
43    if (list->watchers) {
44        SDL_free(list->watchers);
45        list->watchers = NULL;
46        list->count = 0;
47    }
48    SDL_zero(list->filter);
49}
50
51bool SDL_DispatchEventWatchList(SDL_EventWatchList *list, SDL_Event *event)
52{
53    SDL_EventWatcher *filter = &list->filter;
54
55    if (!filter->callback && list->count == 0) {
56        return true;
57    }
58
59    SDL_LockMutex(list->lock);
60    {
61        // Make sure we only dispatch the current watcher list
62        int i, count = list->count;
63
64        if (filter->callback && !filter->callback(filter->userdata, event)) {
65            SDL_UnlockMutex(list->lock);
66            return false;
67        }
68
69        list->dispatching = true;
70        for (i = 0; i < count; ++i) {
71            if (!list->watchers[i].removed) {
72                list->watchers[i].callback(list->watchers[i].userdata, event);
73            }
74        }
75        list->dispatching = false;
76
77        if (list->removed) {
78            for (i = list->count; i--;) {
79                if (list->watchers[i].removed) {
80                    --list->count;
81                    if (i < list->count) {
82                        SDL_memmove(&list->watchers[i], &list->watchers[i + 1], (list->count - i) * sizeof(list->watchers[i]));
83                    }
84                }
85            }
86            list->removed = false;
87        }
88    }
89    SDL_UnlockMutex(list->lock);
90
91    return true;
92}
93
94bool SDL_AddEventWatchList(SDL_EventWatchList *list, SDL_EventFilter filter, void *userdata)
95{
96    bool result = true;
97
98    SDL_LockMutex(list->lock);
99    {
100        SDL_EventWatcher *watchers;
101
102        watchers = (SDL_EventWatcher *)SDL_realloc(list->watchers, (list->count + 1) * sizeof(*watchers));
103        if (watchers) {
104            SDL_EventWatcher *watcher;
105
106            list->watchers = watchers;
107            watcher = &list->watchers[list->count];
108            watcher->callback = filter;
109            watcher->userdata = userdata;
110            watcher->removed = false;
111            ++list->count;
112        } else {
113            result = false;
114        }
115    }
116    SDL_UnlockMutex(list->lock);
117
118    return result;
119}
120
121void SDL_RemoveEventWatchList(SDL_EventWatchList *list, SDL_EventFilter filter, void *userdata)
122{
123    SDL_LockMutex(list->lock);
124    {
125        int i;
126
127        for (i = 0; i < list->count; ++i) {
128            if (list->watchers[i].callback == filter && list->watchers[i].userdata == userdata) {
129                if (list->dispatching) {
130                    list->watchers[i].removed = true;
131                    list->removed = true;
132                } else {
133                    --list->count;
134                    if (i < list->count) {
135                        SDL_memmove(&list->watchers[i], &list->watchers[i + 1], (list->count - i) * sizeof(list->watchers[i]));
136                    }
137                }
138                break;
139            }
140        }
141    }
142    SDL_UnlockMutex(list->lock);
143}
144
[FILE END]
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