gio/xdgmime/xdgmimecache.c

   1 /* -*- mode: C; c-file-style: "gnu" -*- */
   2 /* xdgmimealias.c: Private file.  mmappable caches for mime data
   3  *
   4  * More info can be found at http://www.freedesktop.org/standards/
   5  *
   6  * Copyright (C) 2005  Matthias Clasen <mclasen@redhat.com>
   7  *
   8  * Licensed under the Academic Free License version 2.0
   9  * Or under the following terms:
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include <fcntl.h>
  34 #include <unistd.h>
  35 #include <errno.h>
  36 #include <fnmatch.h>
  37 #include <assert.h>
  38
  39 #include <netinet/in.h> /* for ntohl/ntohs */
  40
  41 #ifdef HAVE_MMAP
  42 #include <sys/mman.h>
  43 #else
  44 #warning Building xdgmime without MMAP support. Binary "mime.info" cache files will not be used.
  45 #endif
  46
  47 #include <sys/stat.h>
  48 #include <sys/types.h>
  49
  50 #include "xdgmimecache.h"
  51 #include "xdgmimeint.h"
  52
  53 #ifndef MAX
  54 #define MAX(a,b) ((a) > (b) ? (a) : (b))
  55 #endif
  56
  57 #ifndef FALSE
  58 #define FALSE   (0)
  59 #endif
  60
  61 #ifndef TRUE
  62 #define TRUE    (!FALSE)
  63 #endif
  64
  65 #ifndef _O_BINARY
  66 #define _O_BINARY 0
  67 #endif
  68
  69 #ifndef MAP_FAILED
  70 #define MAP_FAILED ((void *) -1)
  71 #endif
  72
  73 #define MAJOR_VERSION 1
  74 #define MINOR_VERSION_MIN 1
  75 #define MINOR_VERSION_MAX 2
  76
  77 struct _XdgMimeCache
  78 {
  79   int ref_count;
  80   int minor;
  81
  82   size_t  size;
  83   char   *buffer;
  84 };
  85
  86 #define GET_UINT16(cache,offset) (ntohs(*(xdg_uint16_t*)((cache) + (offset))))
  87 #define GET_UINT32(cache,offset) (ntohl(*(xdg_uint32_t*)((cache) + (offset))))
  88
  89 XdgMimeCache *
  90 _xdg_mime_cache_ref (XdgMimeCache *cache)
  91 {
  92   cache->ref_count++;
  93   return cache;
  94 }
  95
  96 void
  97 _xdg_mime_cache_unref (XdgMimeCache *cache)
  98 {
  99   cache->ref_count--;
 100
 101   if (cache->ref_count == 0)
 102     {
 103 #ifdef HAVE_MMAP
 104       munmap (cache->buffer, cache->size);
 105 #endif
 106       free (cache);
 107     }
 108 }
 109
 110 XdgMimeCache *
 111 _xdg_mime_cache_new_from_file (const char *file_name)
 112 {
 113   XdgMimeCache *cache = NULL;
 114
 115 #ifdef HAVE_MMAP
 116   int fd = -1;
 117   struct stat st;
 118   char *buffer = NULL;
 119   int minor;
 120
 121   /* Open the file and map it into memory */
 122   do
 123     fd = open (file_name, O_RDONLY|_O_BINARY, 0);
 124   while (fd == -1 && errno == EINTR);
 125
 126   if (fd < 0)
 127     return NULL;
 128
 129   if (fstat (fd, &st) < 0 || st.st_size < 4)
 130     goto done;
 131
 132   buffer = (char *) mmap (NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
 133
 134   if (buffer == MAP_FAILED)
 135     goto done;
 136
 137   minor = GET_UINT16 (buffer, 2);
 138   /* Verify version */
 139   if (GET_UINT16 (buffer, 0) != MAJOR_VERSION ||
 140       (minor < MINOR_VERSION_MIN ||
 141        minor > MINOR_VERSION_MAX))
 142     {
 143       munmap (buffer, st.st_size);
 144
 145       goto done;
 146     }
 147
 148   cache = (XdgMimeCache *) malloc (sizeof (XdgMimeCache));
 149   cache->minor = minor;
 150   cache->ref_count = 1;
 151   cache->buffer = buffer;
 152   cache->size = st.st_size;
 153
 154  done:
 155   if (fd != -1)
 156     close (fd);
 157
 158 #else /* HAVE_MMAP */
 159   cache = (XdgMimeCache *) malloc (sizeof (XdgMimeCache));
 160   cache->minor = 0;
 161   cache->ref_count = 1;
 162   cache->buffer = NULL;
 163   cache->size = 0;
 164 #endif  /* HAVE_MMAP */
 165
 166   return cache;
 167 }
 168
 169 static int
 170 cache_magic_matchlet_compare_to_data (XdgMimeCache *cache,
 171                                       xdg_uint32_t  offset,
 172                                       const void   *data,
 173                                       size_t        len)
 174 {
 175   xdg_uint32_t range_start = GET_UINT32 (cache->buffer, offset);
 176   xdg_uint32_t range_length = GET_UINT32 (cache->buffer, offset + 4);
 177   xdg_uint32_t data_length = GET_UINT32 (cache->buffer, offset + 12);
 178   xdg_uint32_t data_offset = GET_UINT32 (cache->buffer, offset + 16);
 179   xdg_uint32_t mask_offset = GET_UINT32 (cache->buffer, offset + 20);
 180
 181   int i, j;
 182
 183   for (i = range_start; i < range_start + range_length; i++)
 184     {
 185       int valid_matchlet = TRUE;
 186
 187       if (i + data_length > len)
 188         return FALSE;
 189
 190       if (mask_offset)
 191         {
 192           for (j = 0; j < data_length; j++)
 193             {
 194               if ((((unsigned char *)cache->buffer)[data_offset + j] & ((unsigned char *)cache->buffer)[mask_offset + j]) !=
 195                   ((((unsigned char *) data)[j + i]) & ((unsigned char *)cache->buffer)[mask_offset + j]))
 196                 {
 197                   valid_matchlet = FALSE;
 198                   break;
 199                 }
 200             }
 201         }
 202       else
 203         {
 204           for (j = 0; j < data_length; j++)
 205             {
 206               if (((unsigned char *)cache->buffer)[data_offset + j] != ((unsigned char *) data)[j + i])
 207                 {
 208                   valid_matchlet = FALSE;
 209                   break;
 210                 }
 211             }
 212         }
 213
 214       if (valid_matchlet)
 215         return TRUE;
 216     }
 217
 218   return FALSE;
 219 }
 220
 221 static int
 222 cache_magic_matchlet_compare (XdgMimeCache *cache,
 223                               xdg_uint32_t  offset,
 224                               const void   *data,
 225                               size_t        len)
 226 {
 227   xdg_uint32_t n_children = GET_UINT32 (cache->buffer, offset + 24);
 228   xdg_uint32_t child_offset = GET_UINT32 (cache->buffer, offset + 28);
 229
 230   int i;
 231
 232   if (cache_magic_matchlet_compare_to_data (cache, offset, data, len))
 233     {
 234       if (n_children == 0)
 235         return TRUE;
 236
 237       for (i = 0; i < n_children; i++)
 238         {
 239           if (cache_magic_matchlet_compare (cache, child_offset + 32 * i,
 240                                             data, len))
 241             return TRUE;
 242         }
 243     }
 244
 245   return FALSE;
 246 }
 247
 248 static const char *
 249 cache_magic_compare_to_data (XdgMimeCache *cache,
 250                              xdg_uint32_t  offset,
 251                              const void   *data,
 252                              size_t        len,
 253                              int          *prio)
 254 {
 255   xdg_uint32_t priority = GET_UINT32 (cache->buffer, offset);
 256   xdg_uint32_t mimetype_offset = GET_UINT32 (cache->buffer, offset + 4);
 257   xdg_uint32_t n_matchlets = GET_UINT32 (cache->buffer, offset + 8);
 258   xdg_uint32_t matchlet_offset = GET_UINT32 (cache->buffer, offset + 12);
 259
 260   int i;
 261
 262   for (i = 0; i < n_matchlets; i++)
 263     {
 264       if (cache_magic_matchlet_compare (cache, matchlet_offset + i * 32,
 265                                         data, len))
 266         {
 267           *prio = priority;
 268
 269           return cache->buffer + mimetype_offset;
 270         }
 271     }
 272
 273   return NULL;
 274 }
 275
 276 static const char *
 277 cache_magic_lookup_data (XdgMimeCache *cache,
 278                          const void   *data,
 279                          size_t        len,
 280                          int          *prio,
 281                          const char   *mime_types[],
 282                          int           n_mime_types)
 283 {
 284   xdg_uint32_t list_offset;
 285   xdg_uint32_t n_entries;
 286   xdg_uint32_t offset;
 287
 288   int j, n;
 289
 290   *prio = 0;
 291
 292   list_offset = GET_UINT32 (cache->buffer, 24);
 293   n_entries = GET_UINT32 (cache->buffer, list_offset);
 294   offset = GET_UINT32 (cache->buffer, list_offset + 8);
 295
 296   for (j = 0; j < n_entries; j++)
 297     {
 298       const char *match;
 299
 300       match = cache_magic_compare_to_data (cache, offset + 16 * j,
 301                                            data, len, prio);
 302       if (match)
 303         return match;
 304       else
 305         {
 306           xdg_uint32_t mimetype_offset;
 307           const char *non_match;
 308
 309           mimetype_offset = GET_UINT32 (cache->buffer, offset + 16 * j + 4);
 310           non_match = cache->buffer + mimetype_offset;
 311
 312           for (n = 0; n < n_mime_types; n++)
 313             {
 314               if (mime_types[n] &&
 315                   _xdg_mime_mime_type_equal (mime_types[n], non_match))
 316                 mime_types[n] = NULL;
 317             }
 318         }
 319     }
 320
 321   return NULL;
 322 }
 323
 324 static const char *
 325 cache_alias_lookup (const char *alias)
 326 {
 327   const char *ptr;
 328   int i, min, max, mid, cmp;
 329
 330   for (i = 0; _caches[i]; i++)
 331     {
 332       XdgMimeCache *cache = _caches[i];
 333       xdg_uint32_t list_offset;
 334       xdg_uint32_t n_entries;
 335       xdg_uint32_t offset;
 336
 337       if (cache->buffer == NULL)
 338         continue;
 339
 340       list_offset = GET_UINT32 (cache->buffer, 4);
 341       n_entries = GET_UINT32 (cache->buffer, list_offset);
 342
 343       min = 0;
 344       max = n_entries - 1;
 345       while (max >= min)
 346         {
 347           mid = (min + max) / 2;
 348
 349           offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * mid);
 350           ptr = cache->buffer + offset;
 351           cmp = strcmp (ptr, alias);
 352
 353           if (cmp < 0)
 354             min = mid + 1;
 355           else if (cmp > 0)
 356             max = mid - 1;
 357           else
 358             {
 359               offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * mid + 4);
 360               return cache->buffer + offset;
 361             }
 362         }
 363     }
 364
 365   return NULL;
 366 }
 367
 368 typedef struct {
 369   const char *mime;
 370   int weight;
 371 } MimeWeight;
 372
 373 static int
 374 cache_glob_lookup_literal (const char *file_name,
 375                            const char *mime_types[],
 376                            int         n_mime_types,
 377                            int         case_sensitive_check)
 378 {
 379   const char *ptr;
 380   int i, min, max, mid, cmp;
 381
 382   for (i = 0; _caches[i]; i++)
 383     {
 384       XdgMimeCache *cache = _caches[i];
 385       xdg_uint32_t list_offset;
 386       xdg_uint32_t n_entries;
 387       xdg_uint32_t offset;
 388
 389       if (cache->buffer == NULL)
 390         continue;
 391
 392       list_offset = GET_UINT32 (cache->buffer, 12);
 393       n_entries = GET_UINT32 (cache->buffer, list_offset);
 394
 395       min = 0;
 396       max = n_entries - 1;
 397       while (max >= min)
 398         {
 399           mid = (min + max) / 2;
 400
 401           offset = GET_UINT32 (cache->buffer, list_offset + 4 + 12 * mid);
 402           ptr = cache->buffer + offset;
 403           cmp = strcmp (ptr, file_name);
 404
 405           if (cmp < 0)
 406             min = mid + 1;
 407           else if (cmp > 0)
 408             max = mid - 1;
 409           else
 410             {
 411               int weight = GET_UINT32 (cache->buffer, list_offset + 4 + 12 * mid + 8);
 412               int case_sensitive = weight & 0x100;
 413               weight = weight & 0xff;
 414
 415               if (case_sensitive_check || !case_sensitive)
 416                 {
 417                   offset = GET_UINT32 (cache->buffer, list_offset + 4 + 12 * mid + 4);
 418                   mime_types[0] = (const char *)(cache->buffer + offset);
 419
 420                   return 1;
 421                 }
 422               return 0;
 423             }
 424         }
 425     }
 426
 427   return 0;
 428 }
 429
 430 static int
 431 cache_glob_lookup_fnmatch (const char *file_name,
 432                            MimeWeight  mime_types[],
 433                            int         n_mime_types)
 434 {
 435   const char *mime_type;
 436   const char *ptr;
 437
 438   int i, j, n;
 439
 440   n = 0;
 441   for (i = 0; _caches[i]; i++)
 442     {
 443       XdgMimeCache *cache = _caches[i];
 444
 445       xdg_uint32_t list_offset;
 446       xdg_uint32_t n_entries;
 447
 448       if (cache->buffer == NULL)
 449         continue;
 450
 451       list_offset = GET_UINT32 (cache->buffer, 20);
 452       n_entries = GET_UINT32 (cache->buffer, list_offset);
 453
 454       for (j = 0; j < n_entries && n < n_mime_types; j++)
 455         {
 456           xdg_uint32_t offset = GET_UINT32 (cache->buffer, list_offset + 4 + 12 * j);
 457           xdg_uint32_t mimetype_offset = GET_UINT32 (cache->buffer, list_offset + 4 + 12 * j + 4);
 458           int weight = GET_UINT32 (cache->buffer, list_offset + 4 + 12 * j + 8);
 459           weight = weight & 0xff;
 460           ptr = cache->buffer + offset;
 461           mime_type = cache->buffer + mimetype_offset;
 462
 463           /* FIXME: Not UTF-8 safe */
 464           if (fnmatch (ptr, file_name, 0) == 0)
 465             {
 466               mime_types[n].mime = mime_type;
 467               mime_types[n].weight = weight;
 468               n++;
 469             }
 470         }
 471
 472       if (n == n_mime_types)
 473         break;
 474     }
 475
 476   return n;
 477 }
 478
 479 static int
 480 cache_glob_node_lookup_suffix (XdgMimeCache  *cache,
 481                                xdg_uint32_t   n_entries,
 482                                xdg_uint32_t   offset,
 483                                const char    *file_name,
 484                                int            len,
 485                                int            case_sensitive_check,
 486                                MimeWeight     mime_types[],
 487                                int            n_mime_types)
 488 {
 489   xdg_unichar_t character;
 490   xdg_unichar_t match_char;
 491   xdg_uint32_t mimetype_offset;
 492   xdg_uint32_t n_children;
 493   xdg_uint32_t child_offset;
 494   int weight;
 495   int case_sensitive;
 496
 497   int min, max, mid, n, i;
 498
 499   character = file_name[len - 1];
 500
 501   assert (character != 0);
 502
 503   min = 0;
 504   max = n_entries - 1;
 505   while (max >= min)
 506     {
 507       mid = (min + max) /  2;
 508       match_char = GET_UINT32 (cache->buffer, offset + 12 * mid);
 509       if (match_char < character)
 510         min = mid + 1;
 511       else if (match_char > character)
 512         max = mid - 1;
 513       else
 514         {
 515           len--;
 516           n = 0;
 517           n_children = GET_UINT32 (cache->buffer, offset + 12 * mid + 4);
 518           child_offset = GET_UINT32 (cache->buffer, offset + 12 * mid + 8);
 519
 520           if (len > 0)
 521             {
 522               n = cache_glob_node_lookup_suffix (cache,
 523                                                  n_children, child_offset,
 524                                                  file_name, len,
 525                                                  case_sensitive_check,
 526                                                  mime_types,
 527                                                  n_mime_types);
 528             }
 529           if (n == 0)
 530             {
 531               i = 0;
 532               while (n < n_mime_types && i < n_children)
 533                 {
 534                   match_char = GET_UINT32 (cache->buffer, child_offset + 12 * i);
 535                   if (match_char != 0)
 536                     break;
 537
 538                   mimetype_offset = GET_UINT32 (cache->buffer, child_offset + 12 * i + 4);
 539                   weight = GET_UINT32 (cache->buffer, child_offset + 12 * i + 8);
 540                   case_sensitive = weight & 0x100;
 541                   weight = weight & 0xff;
 542
 543                   if (case_sensitive_check || !case_sensitive)
 544                     {
 545                       mime_types[n].mime = cache->buffer + mimetype_offset;
 546                       mime_types[n].weight = weight;
 547                       n++;
 548                     }
 549                   i++;
 550                 }
 551             }
 552           return n;
 553         }
 554     }
 555   return 0;
 556 }
 557
 558 static int
 559 cache_glob_lookup_suffix (const char *file_name,
 560                           int         len,
 561                           int         ignore_case,
 562                           MimeWeight  mime_types[],
 563                           int         n_mime_types)
 564 {
 565   int i, n;
 566
 567   n = 0;
 568   for (i = 0; _caches[i]; i++)
 569     {
 570       XdgMimeCache *cache = _caches[i];
 571
 572       xdg_uint32_t list_offset;
 573       xdg_uint32_t n_entries;
 574       xdg_uint32_t offset;
 575
 576       if (cache->buffer == NULL)
 577         continue;
 578
 579       list_offset = GET_UINT32 (cache->buffer, 16);
 580       n_entries = GET_UINT32 (cache->buffer, list_offset);
 581       offset = GET_UINT32 (cache->buffer, list_offset + 4);
 582
 583       n += cache_glob_node_lookup_suffix (cache,
 584                                           n_entries, offset,
 585                                           file_name, len,
 586                                           ignore_case,
 587                                           mime_types + n,
 588                                           n_mime_types - n);
 589       if (n == n_mime_types)
 590         break;
 591     }
 592
 593   return n;
 594 }
 595
 596 static int compare_mime_weight (const void *a, const void *b)
 597 {
 598   const MimeWeight *aa = (const MimeWeight *)a;
 599   const MimeWeight *bb = (const MimeWeight *)b;
 600
 601   return bb->weight - aa->weight;
 602 }
 603
 604 #define ISUPPER(c)              ((c) >= 'A' && (c) <= 'Z')
 605 static char *
 606 ascii_tolower (const char *str)
 607 {
 608   char *p, *lower;
 609
 610   lower = strdup (str);
 611   p = lower;
 612   while (*p != 0)
 613     {
 614       char c = *p;
 615       *p++ = ISUPPER (c) ? c - 'A' + 'a' : c;
 616     }
 617   return lower;
 618 }
 619
 620 static int
 621 filter_out_dupes (MimeWeight mimes[], int n_mimes)
 622 {
 623   int last;
 624   int i, j;
 625
 626   last = n_mimes;
 627
 628   for (i = 0; i < last; i++)
 629     {
 630       j = i + 1;
 631       while (j < last)
 632         {
 633           if (strcmp (mimes[i].mime, mimes[j].mime) == 0)
 634             {
 635               mimes[i].weight = MAX (mimes[i].weight, mimes[j].weight);
 636               last--;
 637               mimes[j].mime = mimes[last].mime;
 638               mimes[j].weight = mimes[last].weight;
 639             }
 640           else
 641             j++;
 642         }
 643     }
 644
 645   return last;
 646 }
 647
 648 static int
 649 cache_glob_lookup_file_name (const char *file_name,
 650                              const char *mime_types[],
 651                              int         n_mime_types)
 652 {
 653   int n;
 654   MimeWeight mimes[10];
 655   int n_mimes = 10;
 656   int i;
 657   int len;
 658   char *lower_case;
 659
 660   assert (file_name != NULL && n_mime_types > 0);
 661
 662   /* First, check the literals */
 663
 664   lower_case = ascii_tolower (file_name);
 665
 666   n = cache_glob_lookup_literal (lower_case, mime_types, n_mime_types, FALSE);
 667   if (n > 0)
 668     {
 669       free (lower_case);
 670       return n;
 671     }
 672
 673   n = cache_glob_lookup_literal (file_name, mime_types, n_mime_types, TRUE);
 674   if (n > 0)
 675     {
 676       free (lower_case);
 677       return n;
 678     }
 679
 680   len = strlen (file_name);
 681   n = cache_glob_lookup_suffix (lower_case, len, FALSE, mimes, n_mimes);
 682   if (n < 2)
 683     n += cache_glob_lookup_suffix (file_name, len, TRUE, mimes + n, n_mimes - n);
 684
 685   free (lower_case);
 686
 687   /* Last, try fnmatch */
 688   if (n < 2)
 689     n += cache_glob_lookup_fnmatch (file_name, mimes + n, n_mimes - n);
 690
 691   n = filter_out_dupes (mimes, n);
 692
 693   qsort (mimes, n, sizeof (MimeWeight), compare_mime_weight);
 694
 695   if (n_mime_types < n)
 696     n = n_mime_types;
 697
 698   for (i = 0; i < n; i++)
 699     mime_types[i] = mimes[i].mime;
 700
 701   return n;
 702 }
 703
 704 int
 705 _xdg_mime_cache_get_max_buffer_extents (void)
 706 {
 707   xdg_uint32_t offset;
 708   xdg_uint32_t max_extent;
 709   int i;
 710
 711   max_extent = 0;
 712   for (i = 0; _caches[i]; i++)
 713     {
 714       XdgMimeCache *cache = _caches[i];
 715
 716       if (cache->buffer == NULL)
 717         continue;
 718
 719       offset = GET_UINT32 (cache->buffer, 24);
 720       max_extent = MAX (max_extent, GET_UINT32 (cache->buffer, offset + 4));
 721     }
 722
 723   return max_extent;
 724 }
 725
 726 static const char *
 727 cache_get_mime_type_for_data (const void *data,
 728                               size_t      len,
 729                               int        *result_prio,
 730                               const char *mime_types[],
 731                               int         n_mime_types)
 732 {
 733   const char *mime_type;
 734   int i, n, priority;
 735
 736   priority = 0;
 737   mime_type = NULL;
 738   for (i = 0; _caches[i]; i++)
 739     {
 740       XdgMimeCache *cache = _caches[i];
 741
 742       int prio;
 743       const char *match;
 744
 745       if (cache->buffer == NULL)
 746         continue;
 747
 748       match = cache_magic_lookup_data (cache, data, len, &prio,
 749                                        mime_types, n_mime_types);
 750       if (prio > priority)
 751         {
 752           priority = prio;
 753           mime_type = match;
 754         }
 755     }
 756
 757   if (result_prio)
 758     *result_prio = priority;
 759
 760   if (priority > 0)
 761     return mime_type;
 762
 763   for (n = 0; n < n_mime_types; n++)
 764     {
 765
 766       if (mime_types[n])
 767         return mime_types[n];
 768     }
 769
 770   return XDG_MIME_TYPE_UNKNOWN;
 771 }
 772
 773 const char *
 774 _xdg_mime_cache_get_mime_type_for_data (const void *data,
 775                                         size_t      len,
 776                                         int        *result_prio)
 777 {
 778   return cache_get_mime_type_for_data (data, len, result_prio, NULL, 0);
 779 }
 780
 781 #ifdef NOT_USED_IN_GIO
 782
 783 const char *
 784 _xdg_mime_cache_get_mime_type_for_file (const char  *file_name,
 785                                         struct stat *statbuf)
 786 {
 787   const char *mime_type;
 788   const char *mime_types[10];
 789   FILE *file;
 790   unsigned char *data;
 791   int max_extent;
 792   int bytes_read;
 793   struct stat buf;
 794   const char *base_name;
 795   int n;
 796
 797   if (file_name == NULL)
 798     return NULL;
 799
 800   if (! _xdg_utf8_validate (file_name))
 801     return NULL;
 802
 803   base_name = _xdg_get_base_name (file_name);
 804   n = cache_glob_lookup_file_name (base_name, mime_types, 10);
 805
 806   if (n == 1)
 807     return mime_types[0];
 808
 809   if (!statbuf)
 810     {
 811       if (stat (file_name, &buf) != 0)
 812         return XDG_MIME_TYPE_UNKNOWN;
 813
 814       statbuf = &buf;
 815     }
 816
 817   if (!S_ISREG (statbuf->st_mode))
 818     return XDG_MIME_TYPE_UNKNOWN;
 819
 820   /* FIXME: Need to make sure that max_extent isn't totally broken.  This could
 821    * be large and need getting from a stream instead of just reading it all
 822    * in. */
 823   max_extent = _xdg_mime_cache_get_max_buffer_extents ();
 824   data = malloc (max_extent);
 825   if (data == NULL)
 826     return XDG_MIME_TYPE_UNKNOWN;
 827
 828   file = fopen (file_name, "r");
 829   if (file == NULL)
 830     {
 831       free (data);
 832       return XDG_MIME_TYPE_UNKNOWN;
 833     }
 834
 835   bytes_read = fread (data, 1, max_extent, file);
 836   if (ferror (file))
 837     {
 838       free (data);
 839       fclose (file);
 840       return XDG_MIME_TYPE_UNKNOWN;
 841     }
 842
 843   mime_type = cache_get_mime_type_for_data (data, bytes_read, NULL,
 844                                             mime_types, n);
 845
 846   free (data);
 847   fclose (file);
 848
 849   return mime_type;
 850 }
 851
 852 const char *
 853 _xdg_mime_cache_get_mime_type_from_file_name (const char *file_name)
 854 {
 855   const char *mime_type;
 856
 857   if (cache_glob_lookup_file_name (file_name, &mime_type, 1))
 858     return mime_type;
 859   else
 860     return XDG_MIME_TYPE_UNKNOWN;
 861 }
 862
 863 #endif
 864
 865 int
 866 _xdg_mime_cache_get_mime_types_from_file_name (const char *file_name,
 867                                                const char  *mime_types[],
 868                                                int          n_mime_types)
 869 {
 870   return cache_glob_lookup_file_name (file_name, mime_types, n_mime_types);
 871 }
 872
 873 #if 1
 874 static int
 875 ends_with (const char *str,
 876            const char *suffix)
 877 {
 878   int length;
 879   int suffix_length;
 880
 881   length = strlen (str);
 882   suffix_length = strlen (suffix);
 883   if (length < suffix_length)
 884     return 0;
 885
 886   if (strcmp (str + length - suffix_length, suffix) == 0)
 887     return 1;
 888
 889   return 0;
 890 }
 891
 892 static int
 893 is_super_type (const char *mime)
 894 {
 895   return ends_with (mime, "/*");
 896 }
 897 #endif
 898
 899 int
 900 _xdg_mime_cache_mime_type_subclass (const char *mime,
 901                                     const char *base)
 902 {
 903   const char *umime, *ubase;
 904
 905   int i, j, min, max, med, cmp;
 906
 907   umime = _xdg_mime_cache_unalias_mime_type (mime);
 908   ubase = _xdg_mime_cache_unalias_mime_type (base);
 909
 910   if (strcmp (umime, ubase) == 0)
 911     return 1;
 912
 913   /* We really want to handle text/ * in GtkFileFilter, so we just
 914    * turn on the supertype matching
 915    */
 916 #if 1
 917   /* Handle supertypes */
 918   if (is_super_type (ubase) &&
 919       xdg_mime_media_type_equal (umime, ubase))
 920     return 1;
 921 #endif
 922
 923   /*  Handle special cases text/plain and application/octet-stream */
 924   if (strcmp (ubase, "text/plain") == 0 &&
 925       strncmp (umime, "text/", 5) == 0)
 926     return 1;
 927
 928   if (strcmp (ubase, "application/octet-stream") == 0)
 929     return 1;
 930
 931   for (i = 0; _caches[i]; i++)
 932     {
 933       XdgMimeCache *cache = _caches[i];
 934       xdg_uint32_t list_offset;
 935       xdg_uint32_t n_entries;
 936       xdg_uint32_t offset, n_parents, parent_offset;
 937
 938       if (cache->buffer == NULL)
 939         continue;
 940
 941       list_offset = GET_UINT32 (cache->buffer, 8);
 942       n_entries = GET_UINT32 (cache->buffer, list_offset);
 943
 944       min = 0;
 945       max = n_entries - 1;
 946       while (max >= min)
 947         {
 948           med = (min + max)/2;
 949
 950           offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * med);
 951           cmp = strcmp (cache->buffer + offset, umime);
 952           if (cmp < 0)
 953             min = med + 1;
 954           else if (cmp > 0)
 955             max = med - 1;
 956           else
 957             {
 958               offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * med + 4);
 959               n_parents = GET_UINT32 (cache->buffer, offset);
 960
 961               for (j = 0; j < n_parents; j++)
 962                 {
 963                   parent_offset = GET_UINT32 (cache->buffer, offset + 4 + 4 * j);
 964                   if (_xdg_mime_cache_mime_type_subclass (cache->buffer + parent_offset, ubase))
 965                     return 1;
 966                 }
 967
 968               break;
 969             }
 970         }
 971     }
 972
 973   return 0;
 974 }
 975
 976 const char *
 977 _xdg_mime_cache_unalias_mime_type (const char *mime)
 978 {
 979   const char *lookup;
 980
 981   lookup = cache_alias_lookup (mime);
 982
 983   if (lookup)
 984     return lookup;
 985
 986   return mime;
 987 }
 988
 989 char **
 990 _xdg_mime_cache_list_mime_parents (const char *mime)
 991 {
 992   int i, j, k, l, p;
 993   char *all_parents[128]; /* we'll stop at 128 */
 994   char **result;
 995
 996   mime = xdg_mime_unalias_mime_type (mime);
 997
 998   p = 0;
 999   for (i = 0; _caches[i]; i++)
1000     {
1001       XdgMimeCache *cache = _caches[i];
1002       xdg_uint32_t list_offset;
1003       xdg_uint32_t n_entries;
1004
1005       if (cache->buffer == NULL)
1006         continue;
1007
1008       list_offset = GET_UINT32 (cache->buffer, 8);
1009       n_entries = GET_UINT32 (cache->buffer, list_offset);
1010
1011       for (j = 0; j < n_entries; j++)
1012         {
1013           xdg_uint32_t mimetype_offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * j);
1014           xdg_uint32_t parents_offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * j + 4);
1015
1016           if (strcmp (cache->buffer + mimetype_offset, mime) == 0)
1017             {
1018               xdg_uint32_t parent_mime_offset;
1019               xdg_uint32_t n_parents = GET_UINT32 (cache->buffer, parents_offset);
1020
1021               for (k = 0; k < n_parents && p < 127; k++)
1022                 {
1023                   parent_mime_offset = GET_UINT32 (cache->buffer, parents_offset + 4 + 4 * k);
1024
1025                   /* Don't add same parent multiple times.
1026                    * This can happen for instance if the same type is listed in multiple directories
1027                    */
1028                   for (l = 0; l < p; l++)
1029                     {
1030                       if (strcmp (all_parents[l], cache->buffer + parent_mime_offset) == 0)
1031                         break;
1032                     }
1033
1034                   if (l == p)
1035                     all_parents[p++] = cache->buffer + parent_mime_offset;
1036                 }
1037
1038               break;
1039             }
1040         }
1041     }
1042   all_parents[p++] = NULL;
1043
1044   result = (char **) malloc (p * sizeof (char *));
1045   memcpy (result, all_parents, p * sizeof (char *));
1046
1047   return result;
1048 }
1049
1050 static const char *
1051 cache_lookup_icon (const char *mime, int header)
1052 {
1053   const char *ptr;
1054   int i, min, max, mid, cmp;
1055
1056   for (i = 0; _caches[i]; i++)
1057     {
1058       XdgMimeCache *cache = _caches[i];
1059       xdg_uint32_t list_offset;
1060       xdg_uint32_t n_entries;
1061       xdg_uint32_t offset;
1062
1063       if (cache->buffer == NULL)
1064         continue;
1065
1066       list_offset = GET_UINT32 (cache->buffer, header);
1067       n_entries = GET_UINT32 (cache->buffer, list_offset);
1068
1069       min = 0;
1070       max = n_entries - 1;
1071       while (max >= min)
1072         {
1073           mid = (min + max) / 2;
1074
1075           offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * mid);
1076           ptr = cache->buffer + offset;
1077           cmp = strcmp (ptr, mime);
1078
1079           if (cmp < 0)
1080             min = mid + 1;
1081           else if (cmp > 0)
1082             max = mid - 1;
1083           else
1084             {
1085               offset = GET_UINT32 (cache->buffer, list_offset + 4 + 8 * mid + 4);
1086               return cache->buffer + offset;
1087             }
1088         }
1089     }
1090
1091   return NULL;
1092 }
1093
1094 const char *
1095 _xdg_mime_cache_get_generic_icon (const char *mime)
1096 {
1097   return cache_lookup_icon (mime, 36);
1098 }
1099
1100 const char *
1101 _xdg_mime_cache_get_icon (const char *mime)
1102 {
1103   return cache_lookup_icon (mime, 32);
1104 }
1105
1106 #ifdef NOT_USED_IN_GIO
1107
1108 static void
1109 dump_glob_node (XdgMimeCache *cache,
1110                 xdg_uint32_t  offset,
1111                 int           depth)
1112 {
1113   xdg_unichar_t character;
1114   xdg_uint32_t mime_offset;
1115   xdg_uint32_t n_children;
1116   xdg_uint32_t child_offset;
1117   int i;
1118
1119   character = GET_UINT32 (cache->buffer, offset);
1120   mime_offset = GET_UINT32 (cache->buffer, offset + 4);
1121   n_children = GET_UINT32 (cache->buffer, offset + 8);
1122   child_offset = GET_UINT32 (cache->buffer, offset + 12);
1123   for (i = 0; i < depth; i++)
1124     printf (" ");
1125   printf ("%c", character);
1126   if (mime_offset)
1127     printf (" - %s", cache->buffer + mime_offset);
1128   printf ("\n");
1129   if (child_offset)
1130   {
1131     for (i = 0; i < n_children; i++)
1132       dump_glob_node (cache, child_offset + 20 * i, depth + 1);
1133   }
1134 }
1135
1136 void
1137 _xdg_mime_cache_glob_dump (void)
1138 {
1139   int i, j;
1140   for (i = 0; _caches[i]; i++)
1141   {
1142     XdgMimeCache *cache = _caches[i];
1143     xdg_uint32_t list_offset;
1144     xdg_uint32_t n_entries;
1145     xdg_uint32_t offset;
1146
1147       if (cache->buffer == NULL)
1148         continue;
1149
1150     list_offset = GET_UINT32 (cache->buffer, 16);
1151     n_entries = GET_UINT32 (cache->buffer, list_offset);
1152     offset = GET_UINT32 (cache->buffer, list_offset + 4);
1153     for (j = 0; j < n_entries; j++)
1154             dump_glob_node (cache, offset + 20 * j, 0);
1155   }
1156 }
1157
1158 #endif