1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2021 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_hints.h"
24#include "SDL_error.h"
25#include "SDL_hints_c.h"
26
27
28/* Assuming there aren't many hints set and they aren't being queried in
29 critical performance paths, we'll just use linked lists here.
30 */
31typedef struct SDL_HintWatch {
32 SDL_HintCallback callback;
33 void *userdata;
34 struct SDL_HintWatch *next;
35} SDL_HintWatch;
36
37typedef struct SDL_Hint {
38 char *name;
39 char *value;
40 SDL_HintPriority priority;
41 SDL_HintWatch *callbacks;
42 struct SDL_Hint *next;
43} SDL_Hint;
44
45static SDL_Hint *SDL_hints;
46
47SDL_bool
48SDL_SetHintWithPriority(const char *name, const char *value,
49 SDL_HintPriority priority)
50{
51 const char *env;
52 SDL_Hint *hint;
53 SDL_HintWatch *entry;
54
55 if (!name || !value) {
56 return SDL_FALSE;
57 }
58
59 env = SDL_getenv(name);
60 if (env && priority < SDL_HINT_OVERRIDE) {
61 return SDL_FALSE;
62 }
63
64 for (hint = SDL_hints; hint; hint = hint->next) {
65 if (SDL_strcmp(name, hint->name) == 0) {
66 if (priority < hint->priority) {
67 return SDL_FALSE;
68 }
69 if (!hint->value || !value || SDL_strcmp(hint->value, value) != 0) {
70 for (entry = hint->callbacks; entry; ) {
71 /* Save the next entry in case this one is deleted */
72 SDL_HintWatch *next = entry->next;
73 entry->callback(entry->userdata, name, hint->value, value);
74 entry = next;
75 }
76 SDL_free(hint->value);
77 hint->value = value ? SDL_strdup(value) : NULL;
78 }
79 hint->priority = priority;
80 return SDL_TRUE;
81 }
82 }
83
84 /* Couldn't find the hint, add a new one */
85 hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
86 if (!hint) {
87 return SDL_FALSE;
88 }
89 hint->name = SDL_strdup(name);
90 hint->value = value ? SDL_strdup(value) : NULL;
91 hint->priority = priority;
92 hint->callbacks = NULL;
93 hint->next = SDL_hints;
94 SDL_hints = hint;
95 return SDL_TRUE;
96}
97
98SDL_bool
99SDL_SetHint(const char *name, const char *value)
100{
101 return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
102}
103
104const char *
105SDL_GetHint(const char *name)
106{
107 const char *env;
108 SDL_Hint *hint;
109
110 env = SDL_getenv(name);
111 for (hint = SDL_hints; hint; hint = hint->next) {
112 if (SDL_strcmp(name, hint->name) == 0) {
113 if (!env || hint->priority == SDL_HINT_OVERRIDE) {
114 return hint->value;
115 }
116 break;
117 }
118 }
119 return env;
120}
121
122SDL_bool
123SDL_GetStringBoolean(const char *value, SDL_bool default_value)
124{
125 if (!value || !*value) {
126 return default_value;
127 }
128 if (*value == '0' || SDL_strcasecmp(value, "false") == 0) {
129 return SDL_FALSE;
130 }
131 return SDL_TRUE;
132}
133
134SDL_bool
135SDL_GetHintBoolean(const char *name, SDL_bool default_value)
136{
137 const char *hint = SDL_GetHint(name);
138 return SDL_GetStringBoolean(hint, default_value);
139}
140
141void
142SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
143{
144 SDL_Hint *hint;
145 SDL_HintWatch *entry;
146 const char *value;
147
148 if (!name || !*name) {
149 SDL_InvalidParamError("name");
150 return;
151 }
152 if (!callback) {
153 SDL_InvalidParamError("callback");
154 return;
155 }
156
157 SDL_DelHintCallback(name, callback, userdata);
158
159 entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
160 if (!entry) {
161 SDL_OutOfMemory();
162 return;
163 }
164 entry->callback = callback;
165 entry->userdata = userdata;
166
167 for (hint = SDL_hints; hint; hint = hint->next) {
168 if (SDL_strcmp(name, hint->name) == 0) {
169 break;
170 }
171 }
172 if (!hint) {
173 /* Need to add a hint entry for this watcher */
174 hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
175 if (!hint) {
176 SDL_OutOfMemory();
177 SDL_free(entry);
178 return;
179 }
180 hint->name = SDL_strdup(name);
181 hint->value = NULL;
182 hint->priority = SDL_HINT_DEFAULT;
183 hint->callbacks = NULL;
184 hint->next = SDL_hints;
185 SDL_hints = hint;
186 }
187
188 /* Add it to the callbacks for this hint */
189 entry->next = hint->callbacks;
190 hint->callbacks = entry;
191
192 /* Now call it with the current value */
193 value = SDL_GetHint(name);
194 callback(userdata, name, value, value);
195}
196
197void
198SDL_DelHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
199{
200 SDL_Hint *hint;
201 SDL_HintWatch *entry, *prev;
202
203 for (hint = SDL_hints; hint; hint = hint->next) {
204 if (SDL_strcmp(name, hint->name) == 0) {
205 prev = NULL;
206 for (entry = hint->callbacks; entry; entry = entry->next) {
207 if (callback == entry->callback && userdata == entry->userdata) {
208 if (prev) {
209 prev->next = entry->next;
210 } else {
211 hint->callbacks = entry->next;
212 }
213 SDL_free(entry);
214 break;
215 }
216 prev = entry;
217 }
218 return;
219 }
220 }
221}
222
223void SDL_ClearHints(void)
224{
225 SDL_Hint *hint;
226 SDL_HintWatch *entry;
227
228 while (SDL_hints) {
229 hint = SDL_hints;
230 SDL_hints = hint->next;
231
232 SDL_free(hint->name);
233 SDL_free(hint->value);
234 for (entry = hint->callbacks; entry; ) {
235 SDL_HintWatch *freeable = entry;
236 entry = entry->next;
237 SDL_free(freeable);
238 }
239 SDL_free(hint);
240 }
241}
242
243/* vi: set ts=4 sw=4 expandtab: */
244