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   1 /* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
   2  *
   3  * Permission is hereby granted, free of charge, to any person obtaining a
   4  * copy of this software and associated documentation files (the "Software"),
   5  * to deal in the Software without restriction, including without limitation
   6  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   7  * and/or sell copies of the Software, and to permit persons to whom the
   8  * Software is furnished to do so, subject to the following conditions:
   9  *
  10  * The above copyright notice and this permission notice shall be included in
  11  * all copies or substantial portions of the Software.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  16  * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  17  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  18  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19  *
  20  * Except as contained in this notice, the names of the authors or their
  21  * institutions shall not be used in advertising or otherwise to promote the
  22  * sale, use or other dealings in this Software without prior written
  23  * authorization from the authors.
  24  */
  25
  26 /* Stuff that reads stuff from the server. */
  27
  28 #include <assert.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <stdio.h>
  33 #include <sys/select.h>
  34 #include <errno.h>
  35
  36 #include "xcb.h"
  37 #include "xcbext.h"
  38 #include "xcbint.h"
  39
  40 #define XCB_ERROR 0
  41 #define XCB_REPLY 1
  42
  43 struct event_list {
  44     xcb_generic_event_t *event;
  45     struct event_list *next;
  46 };
  47
  48 struct reply_list {
  49     void *reply;
  50     struct reply_list *next;
  51 };
  52
  53 typedef struct pending_reply {
  54     unsigned int request;
  55     enum workarounds workaround;
  56     int flags;
  57     struct pending_reply *next;
  58 } pending_reply;
  59
  60 typedef struct reader_list {
  61     unsigned int request;
  62     pthread_cond_t *data;
  63     struct reader_list *next;
  64 } reader_list;
  65
  66 static void wake_up_next_reader(xcb_connection_t *c)
  67 {
  68     int pthreadret;
  69     if(c->in.readers)
  70         pthreadret = pthread_cond_signal(c->in.readers->data);
  71     else
  72         pthreadret = pthread_cond_signal(&c->in.event_cond);
  73     assert(pthreadret == 0);
  74 }
  75
  76 static int read_packet(xcb_connection_t *c)
  77 {
  78     xcb_generic_reply_t genrep;
  79     int length = 32;
  80     void *buf;
  81     pending_reply *pend = 0;
  82     struct event_list *event;
  83
  84     /* Wait for there to be enough data for us to read a whole packet */
  85     if(c->in.queue_len < length)
  86         return 0;
  87
  88     /* Get the response type, length, and sequence number. */
  89     memcpy(&genrep, c->in.queue, sizeof(genrep));
  90
  91     /* Compute 32-bit sequence number of this packet. */
  92     if((genrep.response_type & 0x7f) != XCB_KEYMAP_NOTIFY)
  93     {
  94         unsigned int lastread = c->in.request_read;
  95         c->in.request_read = (lastread & 0xffff0000) | genrep.sequence;
  96         if(XCB_SEQUENCE_COMPARE(c->in.request_read, <, lastread))
  97             c->in.request_read += 0x10000;
  98         if(XCB_SEQUENCE_COMPARE(c->in.request_read, >, c->in.request_expected))
  99             c->in.request_expected = c->in.request_read;
 100
 101         if(c->in.request_read != lastread)
 102         {
 103             if(c->in.current_reply)
 104             {
 105                 _xcb_map_put(c->in.replies, lastread, c->in.current_reply);
 106                 c->in.current_reply = 0;
 107                 c->in.current_reply_tail = &c->in.current_reply;
 108             }
 109             c->in.request_completed = c->in.request_read - 1;
 110         }
 111         if(genrep.response_type == XCB_ERROR)
 112             c->in.request_completed = c->in.request_read;
 113
 114         while(c->in.pending_replies &&
 115               XCB_SEQUENCE_COMPARE (c->in.pending_replies->request, <=, c->in.request_completed))
 116         {
 117             pending_reply *oldpend = c->in.pending_replies;
 118             c->in.pending_replies = oldpend->next;
 119             if(!oldpend->next)
 120                 c->in.pending_replies_tail = &c->in.pending_replies;
 121             free(oldpend);
 122         }
 123     }
 124
 125     if(genrep.response_type == XCB_ERROR || genrep.response_type == XCB_REPLY)
 126     {
 127         pend = c->in.pending_replies;
 128         if(pend && pend->request != c->in.request_read)
 129             pend = 0;
 130     }
 131
 132     /* For reply packets, check that the entire packet is available. */
 133     if(genrep.response_type == XCB_REPLY)
 134     {
 135         if(pend && pend->workaround == WORKAROUND_GLX_GET_FB_CONFIGS_BUG)
 136         {
 137             uint32_t *p = (uint32_t *) c->in.queue;
 138             genrep.length = p[2] * p[3] * 2;
 139         }
 140         length += genrep.length * 4;
 141     }
 142
 143     buf = malloc(length + (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t)));
 144     if(!buf)
 145     {
 146         _xcb_conn_shutdown(c);
 147         return 0;
 148     }
 149     if(_xcb_in_read_block(c, buf, length) <= 0)
 150     {
 151         free(buf);
 152         return 0;
 153     }
 154     if(pend && (pend->flags & XCB_REQUEST_DISCARD_REPLY))
 155     {
 156         free(buf);
 157         return 1;
 158     }
 159
 160     if(genrep.response_type != XCB_REPLY)
 161         ((xcb_generic_event_t *) buf)->full_sequence = c->in.request_read;
 162
 163     /* reply, or checked error */
 164     if( genrep.response_type == XCB_REPLY ||
 165        (genrep.response_type == XCB_ERROR && pend && (pend->flags & XCB_REQUEST_CHECKED)))
 166     {
 167         reader_list *reader;
 168         struct reply_list *cur = malloc(sizeof(struct reply_list));
 169         if(!cur)
 170         {
 171             _xcb_conn_shutdown(c);
 172             return 0;
 173         }
 174         cur->reply = buf;
 175         cur->next = 0;
 176         *c->in.current_reply_tail = cur;
 177         c->in.current_reply_tail = &cur->next;
 178         for(reader = c->in.readers;
 179             reader &&
 180             XCB_SEQUENCE_COMPARE(reader->request, <=, c->in.request_read);
 181             reader = reader->next)
 182         {
 183             if(reader->request == c->in.request_read)
 184             {
 185                 pthread_cond_signal(reader->data);
 186                 break;
 187             }
 188         }
 189         return 1;
 190     }
 191
 192     /* event, or unchecked error */
 193     event = malloc(sizeof(struct event_list));
 194     if(!event)
 195     {
 196         _xcb_conn_shutdown(c);
 197         free(buf);
 198         return 0;
 199     }
 200     event->event = buf;
 201     event->next = 0;
 202     *c->in.events_tail = event;
 203     c->in.events_tail = &event->next;
 204     pthread_cond_signal(&c->in.event_cond);
 205     return 1; /* I have something for you... */
 206 }
 207
 208 static xcb_generic_event_t *get_event(xcb_connection_t *c)
 209 {
 210     struct event_list *cur = c->in.events;
 211     xcb_generic_event_t *ret;
 212     if(!c->in.events)
 213         return 0;
 214     ret = cur->event;
 215     c->in.events = cur->next;
 216     if(!cur->next)
 217         c->in.events_tail = &c->in.events;
 218     free(cur);
 219     return ret;
 220 }
 221
 222 static void free_reply_list(struct reply_list *head)
 223 {
 224     while(head)
 225     {
 226         struct reply_list *cur = head;
 227         head = cur->next;
 228         free(cur->reply);
 229         free(cur);
 230     }
 231 }
 232
 233 static int read_block(const int fd, void *buf, const size_t len)
 234 {
 235     int done = 0;
 236     while(done < len)
 237     {
 238         int ret = read(fd, ((char *) buf) + done, len - done);
 239         if(ret > 0)
 240             done += ret;
 241         if(ret < 0 && errno == EAGAIN)
 242         {
 243             fd_set fds;
 244             FD_ZERO(&fds);
 245             FD_SET(fd, &fds);
 246             do {
 247                 ret = select(fd + 1, &fds, 0, 0, 0);
 248             } while (ret == -1 && errno == EINTR);
 249         }
 250         if(ret <= 0)
 251             return ret;
 252     }
 253     return len;
 254 }
 255
 256 static int poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 257 {
 258     struct reply_list *head;
 259
 260     /* If an error occurred when issuing the request, fail immediately. */
 261     if(!request)
 262         head = 0;
 263     /* We've read requests past the one we want, so if it has replies we have
 264      * them all and they're in the replies map. */
 265     else if(XCB_SEQUENCE_COMPARE(request, <, c->in.request_read))
 266     {
 267         head = _xcb_map_remove(c->in.replies, request);
 268         if(head && head->next)
 269             _xcb_map_put(c->in.replies, request, head->next);
 270     }
 271     /* We're currently processing the responses to the request we want, and we
 272      * have a reply ready to return. So just return it without blocking. */
 273     else if(request == c->in.request_read && c->in.current_reply)
 274     {
 275         head = c->in.current_reply;
 276         c->in.current_reply = head->next;
 277         if(!head->next)
 278             c->in.current_reply_tail = &c->in.current_reply;
 279     }
 280     /* We know this request can't have any more replies, and we've already
 281      * established it doesn't have a reply now. Don't bother blocking. */
 282     else if(request == c->in.request_completed)
 283         head = 0;
 284     /* We may have more replies on the way for this request: block until we're
 285      * sure. */
 286     else
 287         return 0;
 288
 289     if(error)
 290         *error = 0;
 291     *reply = 0;
 292
 293     if(head)
 294     {
 295         if(((xcb_generic_reply_t *) head->reply)->response_type == XCB_ERROR)
 296         {
 297             if(error)
 298                 *error = head->reply;
 299             else
 300                 free(head->reply);
 301         }
 302         else
 303             *reply = head->reply;
 304
 305         free(head);
 306     }
 307
 308     return 1;
 309 }
 310
 311 /* Public interface */
 312
 313 void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e)
 314 {
 315     void *ret = 0;
 316     if(e)
 317         *e = 0;
 318     if(c->has_error)
 319         return 0;
 320
 321     _xcb_lock_io(c);
 322
 323     /* If this request has not been written yet, write it. */
 324     if(_xcb_out_flush_to(c, request))
 325     {
 326         pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 327         reader_list reader;
 328         reader_list **prev_reader;
 329
 330         for(prev_reader = &c->in.readers;
 331             *prev_reader &&
 332             XCB_SEQUENCE_COMPARE ((*prev_reader)->request, <=, request);
 333             prev_reader = &(*prev_reader)->next)
 334         {
 335             /* empty */;
 336         }
 337         reader.request = request;
 338         reader.data = &cond;
 339         reader.next = *prev_reader;
 340         *prev_reader = &reader;
 341
 342         while(!poll_for_reply(c, request, &ret, e))
 343             if(!_xcb_conn_wait(c, &cond, 0, 0))
 344                 break;
 345
 346         for(prev_reader = &c->in.readers;
 347             *prev_reader &&
 348             XCB_SEQUENCE_COMPARE((*prev_reader)->request, <=, request);
 349             prev_reader = &(*prev_reader)->next)
 350         {
 351             if(*prev_reader == &reader)
 352             {
 353                 *prev_reader = (*prev_reader)->next;
 354                 break;
 355             }
 356         }
 357         pthread_cond_destroy(&cond);
 358     }
 359
 360     wake_up_next_reader(c);
 361     _xcb_unlock_io(c);
 362     return ret;
 363 }
 364
 365 int xcb_poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 366 {
 367     int ret;
 368     if(c->has_error)
 369     {
 370         *reply = 0;
 371         if(error)
 372             *error = 0;
 373         return 1; /* would not block */
 374     }
 375     assert(reply != 0);
 376     _xcb_lock_io(c);
 377     ret = poll_for_reply(c, request, reply, error);
 378     _xcb_unlock_io(c);
 379     return ret;
 380 }
 381
 382 xcb_generic_event_t *xcb_wait_for_event(xcb_connection_t *c)
 383 {
 384     xcb_generic_event_t *ret;
 385     if(c->has_error)
 386         return 0;
 387     _xcb_lock_io(c);
 388     /* get_event returns 0 on empty list. */
 389     while(!(ret = get_event(c)))
 390         if(!_xcb_conn_wait(c, &c->in.event_cond, 0, 0))
 391             break;
 392
 393     wake_up_next_reader(c);
 394     _xcb_unlock_io(c);
 395     return ret;
 396 }
 397
 398 xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c)
 399 {
 400     xcb_generic_event_t *ret = 0;
 401     if(!c->has_error)
 402     {
 403         _xcb_lock_io(c);
 404         /* FIXME: follow X meets Z architecture changes. */
 405         if(_xcb_in_read(c)) /* _xcb_in_read shuts down the connection on error */
 406             ret = get_event(c);
 407         _xcb_unlock_io(c);
 408     }
 409     return ret;
 410 }
 411
 412 xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie)
 413 {
 414     /* FIXME: this could hold the lock to avoid syncing unnecessarily, but
 415      * that would require factoring the locking out of xcb_get_input_focus,
 416      * xcb_get_input_focus_reply, and xcb_wait_for_reply. */
 417     xcb_generic_error_t *ret;
 418     void *reply;
 419     if(c->has_error)
 420         return 0;
 421     if(XCB_SEQUENCE_COMPARE(cookie.sequence,>,c->in.request_expected)
 422        && XCB_SEQUENCE_COMPARE(cookie.sequence,>,c->in.request_completed))
 423     {
 424         free(xcb_get_input_focus_reply(c, xcb_get_input_focus(c), &ret));
 425         assert(!ret);
 426     }
 427     reply = xcb_wait_for_reply(c, cookie.sequence, &ret);
 428     assert(!reply);
 429     return ret;
 430 }
 431
 432 /* Private interface */
 433
 434 int _xcb_in_init(_xcb_in *in)
 435 {
 436     if(pthread_cond_init(&in->event_cond, 0))
 437         return 0;
 438     in->reading = 0;
 439
 440     in->queue_len = 0;
 441
 442     in->request_read = 0;
 443     in->request_completed = 0;
 444
 445     in->replies = _xcb_map_new();
 446     if(!in->replies)
 447         return 0;
 448
 449     in->current_reply_tail = &in->current_reply;
 450     in->events_tail = &in->events;
 451     in->pending_replies_tail = &in->pending_replies;
 452
 453     return 1;
 454 }
 455
 456 void _xcb_in_destroy(_xcb_in *in)
 457 {
 458     pthread_cond_destroy(&in->event_cond);
 459     free_reply_list(in->current_reply);
 460     _xcb_map_delete(in->replies, (void (*)(void *)) free_reply_list);
 461     while(in->events)
 462     {
 463         struct event_list *e = in->events;
 464         in->events = e->next;
 465         free(e->event);
 466         free(e);
 467     }
 468     while(in->pending_replies)
 469     {
 470         pending_reply *pend = in->pending_replies;
 471         in->pending_replies = pend->next;
 472         free(pend);
 473     }
 474 }
 475
 476 int _xcb_in_expect_reply(xcb_connection_t *c, unsigned int request, enum workarounds workaround, int flags)
 477 {
 478     pending_reply *pend = malloc(sizeof(pending_reply));
 479     assert(workaround != WORKAROUND_NONE || flags != 0);
 480     if(!pend)
 481     {
 482         _xcb_conn_shutdown(c);
 483         return 0;
 484     }
 485     pend->request = request;
 486     pend->workaround = workaround;
 487     pend->flags = flags;
 488     pend->next = 0;
 489     *c->in.pending_replies_tail = pend;
 490     c->in.pending_replies_tail = &pend->next;
 491     return 1;
 492 }
 493
 494 int _xcb_in_read(xcb_connection_t *c)
 495 {
 496     int n = read(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len);
 497     if(n > 0)
 498         c->in.queue_len += n;
 499     while(read_packet(c))
 500         /* empty */;
 501     if((n > 0) || (n < 0 && errno == EAGAIN))
 502         return 1;
 503     _xcb_conn_shutdown(c);
 504     return 0;
 505 }
 506
 507 int _xcb_in_read_block(xcb_connection_t *c, void *buf, int len)
 508 {
 509     int done = c->in.queue_len;
 510     if(len < done)
 511         done = len;
 512
 513     memcpy(buf, c->in.queue, done);
 514     c->in.queue_len -= done;
 515     memmove(c->in.queue, c->in.queue + done, c->in.queue_len);
 516
 517     if(len > done)
 518     {
 519         int ret = read_block(c->fd, (char *) buf + done, len - done);
 520         if(ret <= 0)
 521         {
 522             _xcb_conn_shutdown(c);
 523             return ret;
 524         }
 525     }
 526
 527     return len;
 528 }