1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
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