src/events/SDL_events.c
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FUNCTIONS
This source file includes following functions.
- SDL_Lock_EventThread
- SDL_Unlock_EventThread
- SDL_GobbleEvents
- SDL_StartEventThread
- SDL_StopEventThread
- SDL_EventThreadID
- SDL_StopEventLoop
- SDL_StartEventLoop
- SDL_AddEvent
- SDL_CutEvent
- SDL_PeepEvents
- SDL_PumpEvents
- SDL_PollEvent
- SDL_WaitEvent
- SDL_PushEvent
- SDL_SetEventFilter
- SDL_GetEventFilter
- SDL_EventState
- SDL_PrivateSysWMEvent
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id: SDL_events.c,v 1.4.2.20 2001/03/05 17:23:59 hercules Exp $";
26 #endif
27
28 /* General event handling code for SDL */
29
30 #include <stdio.h>
31 #include <string.h>
32
33 #include "SDL.h"
34 #include "SDL_thread.h"
35 #include "SDL_mutex.h"
36 #include "SDL_events.h"
37 #include "SDL_events_c.h"
38 #include "SDL_timer_c.h"
39 #ifndef DISABLE_JOYSTICK
40 #include "SDL_joystick_c.h"
41 #endif
42 #ifndef ENABLE_X11
43 #define DISABLE_X11
44 #endif
45 #include "SDL_syswm.h"
46 #include "SDL_sysevents.h"
47
48 /* Public data -- the event filter */
49 SDL_EventFilter SDL_EventOK = NULL;
50 Uint8 SDL_ProcessEvents[SDL_NUMEVENTS];
51 static Uint32 SDL_eventstate = 0;
52
53 /* Private data -- event queue */
54 #define MAXEVENTS 128
55 static struct {
56 SDL_mutex *lock;
57 int active;
58 int head;
59 int tail;
60 SDL_Event event[MAXEVENTS];
61 int wmmsg_next;
62 struct SDL_SysWMmsg wmmsg[MAXEVENTS];
63 } SDL_EventQ;
64
65 /* Private data -- event locking structure */
66 static struct {
67 SDL_mutex *lock;
68 int safe;
69 } SDL_EventLock;
70
71 /* Thread functions */
72 static SDL_Thread *SDL_EventThread = NULL; /* Thread handle */
73 static Uint32 event_thread; /* The event thread id */
74
75 void SDL_Lock_EventThread(void)
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76 {
77 if ( SDL_EventThread && (SDL_ThreadID() != event_thread) ) {
78 /* Grab lock and spin until we're sure event thread stopped */
79 SDL_mutexP(SDL_EventLock.lock);
80 while ( ! SDL_EventLock.safe ) {
81 SDL_Delay(1);
82 }
83 }
84 }
85 void SDL_Unlock_EventThread(void)
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86 {
87 if ( SDL_EventThread && (SDL_ThreadID() != event_thread) ) {
88 SDL_mutexV(SDL_EventLock.lock);
89 }
90 }
91
92 static int SDL_GobbleEvents(void *unused)
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93 {
94 SDL_SetTimerThreaded(2);
95 event_thread = SDL_ThreadID();
96 while ( SDL_EventQ.active ) {
97 SDL_VideoDevice *video = current_video;
98 SDL_VideoDevice *this = current_video;
99
100 /* Get events from the video subsystem */
101 if ( video ) {
102 video->PumpEvents(this);
103 }
104
105 /* Queue pending key-repeat events */
106 SDL_CheckKeyRepeat();
107
108 #ifndef DISABLE_JOYSTICK
109 /* Check for joystick state change */
110 if ( SDL_numjoysticks && (SDL_eventstate & SDL_JOYEVENTMASK) ) {
111 SDL_JoystickUpdate();
112 }
113 #endif
114
115 /* Give up the CPU for the rest of our timeslice */
116 SDL_EventLock.safe = 1;
117 if( SDL_timer_running ) {
118 SDL_ThreadedTimerCheck();
119 }
120 SDL_Delay(1);
121
122 /* Check for event locking.
123 On the P of the lock mutex, if the lock is held, this thread
124 will wait until the lock is released before continuing. The
125 safe flag will be set, meaning that the other thread can go
126 about it's business. The safe flag is reset before the V,
127 so as soon as the mutex is free, other threads can see that
128 it's not safe to interfere with the event thread.
129 */
130 SDL_mutexP(SDL_EventLock.lock);
131 SDL_EventLock.safe = 0;
132 SDL_mutexV(SDL_EventLock.lock);
133 }
134 SDL_SetTimerThreaded(0);
135 event_thread = 0;
136 return(0);
137 }
138
139 static int SDL_StartEventThread(Uint32 flags)
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140 {
141 /* Reset everything to zero */
142 SDL_EventThread = NULL;
143 memset(&SDL_EventLock, 0, sizeof(SDL_EventLock));
144
145 /* Create the lock and set ourselves active */
146 #ifndef DISABLE_THREADS
147 SDL_EventQ.lock = SDL_CreateMutex();
148 if ( SDL_EventQ.lock == NULL ) {
149 #ifdef macintosh /* On MacOS 7/8, you can't multithread, so no lock needed */
150 ;
151 #else
152 return(-1);
153 #endif
154 }
155 #endif /* !DISABLE_THREADS */
156 SDL_EventQ.active = 1;
157
158 if ( (flags&SDL_INIT_EVENTTHREAD) == SDL_INIT_EVENTTHREAD ) {
159 SDL_EventLock.lock = SDL_CreateMutex();
160 if ( SDL_EventLock.lock == NULL ) {
161 return(-1);
162 }
163 SDL_EventLock.safe = 0;
164
165 SDL_EventThread = SDL_CreateThread(SDL_GobbleEvents, NULL);
166 if ( SDL_EventThread == NULL ) {
167 return(-1);
168 }
169 } else {
170 event_thread = 0;
171 }
172 return(0);
173 }
174
175 static void SDL_StopEventThread(void)
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176 {
177 SDL_EventQ.active = 0;
178 if ( SDL_EventThread ) {
179 SDL_WaitThread(SDL_EventThread, NULL);
180 SDL_EventThread = NULL;
181 SDL_DestroyMutex(SDL_EventLock.lock);
182 }
183 SDL_DestroyMutex(SDL_EventQ.lock);
184 }
185
186 Uint32 SDL_EventThreadID(void)
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187 {
188 return(event_thread);
189 }
190
191 /* Public functions */
192
193 void SDL_StopEventLoop(void)
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194 {
195 /* Halt the event thread, if running */
196 SDL_StopEventThread();
197
198 /* Clean out EventQ */
199 SDL_EventQ.head = 0;
200 SDL_EventQ.tail = 0;
201 SDL_EventQ.wmmsg_next = 0;
202 }
203
204 /* This function (and associated calls) may be called more than once */
205 int SDL_StartEventLoop(Uint32 flags)
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206 {
207 int retcode;
208
209 /* Clean out the event queue */
210 SDL_EventThread = NULL;
211 SDL_EventQ.lock = NULL;
212 SDL_StopEventLoop();
213
214 /* No filter to start with, process most event types */
215 SDL_EventOK = NULL;
216 memset(SDL_ProcessEvents,SDL_ENABLE,sizeof(SDL_ProcessEvents));
217 SDL_eventstate = ~0;
218 /* It's not save to call SDL_EventState() yet */
219 SDL_eventstate &= ~(0x00000001 << SDL_SYSWMEVENT);
220 SDL_ProcessEvents[SDL_SYSWMEVENT] = SDL_IGNORE;
221
222 /* Initialize event handlers */
223 retcode = 0;
224 retcode += SDL_AppActiveInit();
225 retcode += SDL_KeyboardInit();
226 retcode += SDL_MouseInit();
227 retcode += SDL_QuitInit();
228 if ( retcode < 0 ) {
229 /* We don't expect them to fail, but... */
230 return(-1);
231 }
232
233 /* Create the lock and event thread */
234 if ( SDL_StartEventThread(flags) < 0 ) {
235 SDL_StopEventLoop();
236 return(-1);
237 }
238 return(0);
239 }
240
241
242 /* Add an event to the event queue -- called with the queue locked */
243 static int SDL_AddEvent(SDL_Event *event)
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244 {
245 int tail, added;
246
247 tail = (SDL_EventQ.tail+1)%MAXEVENTS;
248 if ( tail == SDL_EventQ.head ) {
249 /* Overflow, drop event */
250 added = 0;
251 } else {
252 SDL_EventQ.event[SDL_EventQ.tail] = *event;
253 if (event->type == SDL_SYSWMEVENT) {
254 /* Note that it's possible to lose an event */
255 int next = SDL_EventQ.wmmsg_next;
256 SDL_EventQ.wmmsg[next] = *event->syswm.msg;
257 SDL_EventQ.event[SDL_EventQ.tail].syswm.msg =
258 &SDL_EventQ.wmmsg[next];
259 SDL_EventQ.wmmsg_next = (next+1)%MAXEVENTS;
260 }
261 SDL_EventQ.tail = tail;
262 added = 1;
263 }
264 return(added);
265 }
266
267 /* Cut an event, and return the next valid spot, or the tail */
268 /* -- called with the queue locked */
269 static int SDL_CutEvent(int spot)
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270 {
271 if ( spot == SDL_EventQ.head ) {
272 SDL_EventQ.head = (SDL_EventQ.head+1)%MAXEVENTS;
273 return(SDL_EventQ.head);
274 } else
275 if ( (spot+1)%MAXEVENTS == SDL_EventQ.tail ) {
276 SDL_EventQ.tail = spot;
277 return(SDL_EventQ.tail);
278 } else
279 /* We cut the middle -- shift everything over */
280 {
281 int here, next;
282
283 /* This can probably be optimized with memcpy() -- careful! */
284 if ( --SDL_EventQ.tail < 0 ) {
285 SDL_EventQ.tail = MAXEVENTS-1;
286 }
287 for ( here=spot; here != SDL_EventQ.tail; here = next ) {
288 next = (here+1)%MAXEVENTS;
289 SDL_EventQ.event[here] = SDL_EventQ.event[next];
290 }
291 return(spot);
292 }
293 /* NOTREACHED */
294 }
295
296 /* Lock the event queue, take a peep at it, and unlock it */
297 int SDL_PeepEvents(SDL_Event *events, int numevents, SDL_eventaction action,
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298 Uint32 mask)
299 {
300 int i, used;
301
302 /* Don't look after we've quit */
303 if ( ! SDL_EventQ.active ) {
304 return(0);
305 }
306 /* Lock the event queue */
307 used = 0;
308 if ( SDL_mutexP(SDL_EventQ.lock) == 0 ) {
309 if ( action == SDL_ADDEVENT ) {
310 for ( i=0; i<numevents; ++i ) {
311 used += SDL_AddEvent(&events[i]);
312 }
313 } else {
314 SDL_Event tmpevent;
315 int spot;
316
317 /* If 'events' is NULL, just see if they exist */
318 if ( events == NULL ) {
319 action = SDL_PEEKEVENT;
320 numevents = 1;
321 events = &tmpevent;
322 }
323 spot = SDL_EventQ.head;
324 while ((used < numevents)&&(spot != SDL_EventQ.tail)) {
325 if ( mask & SDL_EVENTMASK(SDL_EventQ.event[spot].type) ) {
326 events[used++] = SDL_EventQ.event[spot];
327 if ( action == SDL_GETEVENT ) {
328 spot = SDL_CutEvent(spot);
329 } else {
330 spot = (spot+1)%MAXEVENTS;
331 }
332 } else {
333 spot = (spot+1)%MAXEVENTS;
334 }
335 }
336 }
337 SDL_mutexV(SDL_EventQ.lock);
338 } else {
339 SDL_SetError("Couldn't lock event queue");
340 used = -1;
341 }
342 return(used);
343 }
344
345 /* Run the system dependent event loops */
346 void SDL_PumpEvents(void)
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347 {
348 if ( !SDL_EventThread ) {
349 SDL_VideoDevice *video = current_video;
350 SDL_VideoDevice *this = current_video;
351
352 /* Get events from the video subsystem */
353 if ( video ) {
354 video->PumpEvents(this);
355 }
356
357 /* Queue pending key-repeat events */
358 SDL_CheckKeyRepeat();
359
360 #ifndef DISABLE_JOYSTICK
361 /* Check for joystick state change */
362 if ( SDL_numjoysticks && (SDL_eventstate & SDL_JOYEVENTMASK) ) {
363 SDL_JoystickUpdate();
364 }
365 #endif
366 }
367 }
368
369 /* Public functions */
370
371 int SDL_PollEvent (SDL_Event *event)
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372 {
373 SDL_PumpEvents();
374
375 return(SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_ALLEVENTS));
376 }
377
378 int SDL_WaitEvent (SDL_Event *event)
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379 {
380 while ( 1 ) {
381 SDL_PumpEvents();
382 switch(SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_ALLEVENTS)) {
383 case -1: return -1;
384 case 1: return 1;
385 case 0: SDL_Delay(10);
386 }
387 }
388 }
389
390 int SDL_PushEvent(SDL_Event *event)
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391 {
392 return(SDL_PeepEvents(event, 1, SDL_ADDEVENT, 0));
393 }
394
395 void SDL_SetEventFilter (SDL_EventFilter filter)
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396 {
397 SDL_Event bitbucket;
398
399 /* Set filter and discard pending events */
400 SDL_EventOK = filter;
401 while ( SDL_PollEvent(&bitbucket) > 0 )
402 ;
403 }
404
405 SDL_EventFilter SDL_GetEventFilter(void)
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406 {
407 return(SDL_EventOK);
408 }
409
410 Uint8 SDL_EventState (Uint8 type, int state)
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411 {
412 SDL_Event bitbucket;
413 Uint8 current_state;
414
415 /* If SDL_ALLEVENTS was specified... */
416 if ( type == 0xFF ) {
417 current_state = SDL_IGNORE;
418 for ( type=0; type<SDL_NUMEVENTS; ++type ) {
419 if ( SDL_ProcessEvents[type] != SDL_IGNORE ) {
420 current_state = SDL_ENABLE;
421 }
422 SDL_ProcessEvents[type] = state;
423 if ( state == SDL_ENABLE ) {
424 SDL_eventstate |= (0x00000001 << (type));
425 } else {
426 SDL_eventstate &= ~(0x00000001 << (type));
427 }
428 }
429 while ( SDL_PollEvent(&bitbucket) > 0 )
430 ;
431 return(current_state);
432 }
433
434 /* Just set the state for one event type */
435 current_state = SDL_ProcessEvents[type];
436 switch (state) {
437 case SDL_IGNORE:
438 case SDL_ENABLE:
439 /* Set state and discard pending events */
440 SDL_ProcessEvents[type] = state;
441 if ( state == SDL_ENABLE ) {
442 SDL_eventstate |= (0x00000001 << (type));
443 } else {
444 SDL_eventstate &= ~(0x00000001 << (type));
445 }
446 while ( SDL_PollEvent(&bitbucket) > 0 )
447 ;
448 break;
449 default:
450 /* Querying state? */
451 break;
452 }
453 return(current_state);
454 }
455
456 /* This is a generic event handler.
457 */
458 int SDL_PrivateSysWMEvent(SDL_SysWMmsg *message)
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459 {
460 int posted;
461
462 posted = 0;
463 if ( SDL_ProcessEvents[SDL_SYSWMEVENT] == SDL_ENABLE ) {
464 SDL_Event event;
465 memset(&event, 0, sizeof(event));
466 event.type = SDL_SYSWMEVENT;
467 event.syswm.msg = message;
468 if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) {
469 posted = 1;
470 SDL_PushEvent(&event);
471 }
472 }
473 /* Update internal event state */
474 return(posted);
475 }