tree-walk.c

   1 #include "cache.h"
   2 #include "tree-walk.h"
   3 #include "unpack-trees.h"
   4 #include "dir.h"
   5 #include "tree.h"
   6
   7 static const char *get_mode(const char *str, unsigned int *modep)
   8 {
   9         unsigned char c;
  10         unsigned int mode = 0;
  11
  12         if (*str == ' ')
  13                 return NULL;
  14
  15         while ((c = *str++) != ' ') {
  16                 if (c < '0' || c > '7')
  17                         return NULL;
  18                 mode = (mode << 3) + (c - '0');
  19         }
  20         *modep = mode;
  21         return str;
  22 }
  23
  24 static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size)
  25 {
  26         const char *path;
  27         unsigned int mode, len;
  28
  29         if (size < 24 || buf[size - 21])
  30                 die("corrupt tree file");
  31
  32         path = get_mode(buf, &mode);
  33         if (!path || !*path)
  34                 die("corrupt tree file");
  35         len = strlen(path) + 1;
  36
  37         /* Initialize the descriptor entry */
  38         desc->entry.path = path;
  39         desc->entry.mode = mode;
  40         desc->entry.sha1 = (const unsigned char *)(path + len);
  41 }
  42
  43 void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
  44 {
  45         desc->buffer = buffer;
  46         desc->size = size;
  47         if (size)
  48                 decode_tree_entry(desc, buffer, size);
  49 }
  50
  51 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
  52 {
  53         unsigned long size = 0;
  54         void *buf = NULL;
  55
  56         if (sha1) {
  57                 buf = read_object_with_reference(sha1, tree_type, &size, NULL);
  58                 if (!buf)
  59                         die("unable to read tree %s", sha1_to_hex(sha1));
  60         }
  61         init_tree_desc(desc, buf, size);
  62         return buf;
  63 }
  64
  65 static void entry_clear(struct name_entry *a)
  66 {
  67         memset(a, 0, sizeof(*a));
  68 }
  69
  70 static void entry_extract(struct tree_desc *t, struct name_entry *a)
  71 {
  72         *a = t->entry;
  73 }
  74
  75 void update_tree_entry(struct tree_desc *desc)
  76 {
  77         const void *buf = desc->buffer;
  78         const unsigned char *end = desc->entry.sha1 + 20;
  79         unsigned long size = desc->size;
  80         unsigned long len = end - (const unsigned char *)buf;
  81
  82         if (size < len)
  83                 die("corrupt tree file");
  84         buf = end;
  85         size -= len;
  86         desc->buffer = buf;
  87         desc->size = size;
  88         if (size)
  89                 decode_tree_entry(desc, buf, size);
  90 }
  91
  92 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
  93 {
  94         if (!desc->size)
  95                 return 0;
  96
  97         *entry = desc->entry;
  98         update_tree_entry(desc);
  99         return 1;
 100 }
 101
 102 void setup_traverse_info(struct traverse_info *info, const char *base)
 103 {
 104         int pathlen = strlen(base);
 105         static struct traverse_info dummy;
 106
 107         memset(info, 0, sizeof(*info));
 108         if (pathlen && base[pathlen-1] == '/')
 109                 pathlen--;
 110         info->pathlen = pathlen ? pathlen + 1 : 0;
 111         info->name.path = base;
 112         info->name.sha1 = (void *)(base + pathlen + 1);
 113         if (pathlen)
 114                 info->prev = &dummy;
 115 }
 116
 117 char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
 118 {
 119         int len = tree_entry_len(n);
 120         int pathlen = info->pathlen;
 121
 122         path[pathlen + len] = 0;
 123         for (;;) {
 124                 memcpy(path + pathlen, n->path, len);
 125                 if (!pathlen)
 126                         break;
 127                 path[--pathlen] = '/';
 128                 n = &info->name;
 129                 len = tree_entry_len(n);
 130                 info = info->prev;
 131                 pathlen -= len;
 132         }
 133         return path;
 134 }
 135
 136 struct tree_desc_skip {
 137         struct tree_desc_skip *prev;
 138         const void *ptr;
 139 };
 140
 141 struct tree_desc_x {
 142         struct tree_desc d;
 143         struct tree_desc_skip *skip;
 144 };
 145
 146 static int name_compare(const char *a, int a_len,
 147                         const char *b, int b_len)
 148 {
 149         int len = (a_len < b_len) ? a_len : b_len;
 150         int cmp = memcmp(a, b, len);
 151         if (cmp)
 152                 return cmp;
 153         return (a_len - b_len);
 154 }
 155
 156 static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
 157 {
 158         /*
 159          * The caller wants to pick *a* from a tree or nothing.
 160          * We are looking at *b* in a tree.
 161          *
 162          * (0) If a and b are the same name, we are trivially happy.
 163          *
 164          * There are three possibilities where *a* could be hiding
 165          * behind *b*.
 166          *
 167          * (1) *a* == "t",   *b* == "ab"  i.e. *b* sorts earlier than *a* no
 168          *                                matter what.
 169          * (2) *a* == "t",   *b* == "t-2" and "t" is a subtree in the tree;
 170          * (3) *a* == "t-2", *b* == "t"   and "t-2" is a blob in the tree.
 171          *
 172          * Otherwise we know *a* won't appear in the tree without
 173          * scanning further.
 174          */
 175
 176         int cmp = name_compare(a, a_len, b, b_len);
 177
 178         /* Most common case first -- reading sync'd trees */
 179         if (!cmp)
 180                 return cmp;
 181
 182         if (0 < cmp) {
 183                 /* a comes after b; it does not matter if it is case (3)
 184                 if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
 185                         return 1;
 186                 */
 187                 return 1; /* keep looking */
 188         }
 189
 190         /* b comes after a; are we looking at case (2)? */
 191         if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
 192                 return 1; /* keep looking */
 193
 194         return -1; /* a cannot appear in the tree */
 195 }
 196
 197 /*
 198  * From the extended tree_desc, extract the first name entry, while
 199  * paying attention to the candidate "first" name.  Most importantly,
 200  * when looking for an entry, if there are entries that sorts earlier
 201  * in the tree object representation than that name, skip them and
 202  * process the named entry first.  We will remember that we haven't
 203  * processed the first entry yet, and in the later call skip the
 204  * entry we processed early when update_extended_entry() is called.
 205  *
 206  * E.g. if the underlying tree object has these entries:
 207  *
 208  *    blob    "t-1"
 209  *    blob    "t-2"
 210  *    tree    "t"
 211  *    blob    "t=1"
 212  *
 213  * and the "first" asks for "t", remember that we still need to
 214  * process "t-1" and "t-2" but extract "t".  After processing the
 215  * entry "t" from this call, the caller will let us know by calling
 216  * update_extended_entry() that we can remember "t" has been processed
 217  * already.
 218  */
 219
 220 static void extended_entry_extract(struct tree_desc_x *t,
 221                                    struct name_entry *a,
 222                                    const char *first,
 223                                    int first_len)
 224 {
 225         const char *path;
 226         int len;
 227         struct tree_desc probe;
 228         struct tree_desc_skip *skip;
 229
 230         /*
 231          * Extract the first entry from the tree_desc, but skip the
 232          * ones that we already returned in earlier rounds.
 233          */
 234         while (1) {
 235                 if (!t->d.size) {
 236                         entry_clear(a);
 237                         break; /* not found */
 238                 }
 239                 entry_extract(&t->d, a);
 240                 for (skip = t->skip; skip; skip = skip->prev)
 241                         if (a->path == skip->ptr)
 242                                 break; /* found */
 243                 if (!skip)
 244                         break;
 245                 /* We have processed this entry already. */
 246                 update_tree_entry(&t->d);
 247         }
 248
 249         if (!first || !a->path)
 250                 return;
 251
 252         /*
 253          * The caller wants "first" from this tree, or nothing.
 254          */
 255         path = a->path;
 256         len = tree_entry_len(a);
 257         switch (check_entry_match(first, first_len, path, len)) {
 258         case -1:
 259                 entry_clear(a);
 260         case 0:
 261                 return;
 262         default:
 263                 break;
 264         }
 265
 266         /*
 267          * We need to look-ahead -- we suspect that a subtree whose
 268          * name is "first" may be hiding behind the current entry "path".
 269          */
 270         probe = t->d;
 271         while (probe.size) {
 272                 entry_extract(&probe, a);
 273                 path = a->path;
 274                 len = tree_entry_len(a);
 275                 switch (check_entry_match(first, first_len, path, len)) {
 276                 case -1:
 277                         entry_clear(a);
 278                 case 0:
 279                         return;
 280                 default:
 281                         update_tree_entry(&probe);
 282                         break;
 283                 }
 284                 /* keep looking */
 285         }
 286         entry_clear(a);
 287 }
 288
 289 static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
 290 {
 291         if (t->d.entry.path == a->path) {
 292                 update_tree_entry(&t->d);
 293         } else {
 294                 /* we have returned this entry early */
 295                 struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
 296                 skip->ptr = a->path;
 297                 skip->prev = t->skip;
 298                 t->skip = skip;
 299         }
 300 }
 301
 302 static void free_extended_entry(struct tree_desc_x *t)
 303 {
 304         struct tree_desc_skip *p, *s;
 305
 306         for (s = t->skip; s; s = p) {
 307                 p = s->prev;
 308                 free(s);
 309         }
 310 }
 311
 312 static inline int prune_traversal(struct name_entry *e,
 313                                   struct traverse_info *info,
 314                                   struct strbuf *base,
 315                                   int still_interesting)
 316 {
 317         if (!info->pathspec || still_interesting == 2)
 318                 return 2;
 319         if (still_interesting < 0)
 320                 return still_interesting;
 321         return tree_entry_interesting(e, base, 0, info->pathspec);
 322 }
 323
 324 int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 325 {
 326         int error = 0;
 327         struct name_entry *entry = xmalloc(n*sizeof(*entry));
 328         int i;
 329         struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
 330         struct strbuf base = STRBUF_INIT;
 331         int interesting = 1;
 332
 333         for (i = 0; i < n; i++)
 334                 tx[i].d = t[i];
 335
 336         if (info->prev) {
 337                 strbuf_grow(&base, info->pathlen);
 338                 make_traverse_path(base.buf, info->prev, &info->name);
 339                 base.buf[info->pathlen-1] = '/';
 340                 strbuf_setlen(&base, info->pathlen);
 341         }
 342         for (;;) {
 343                 int trees_used;
 344                 unsigned long mask, dirmask;
 345                 const char *first = NULL;
 346                 int first_len = 0;
 347                 struct name_entry *e = NULL;
 348                 int len;
 349
 350                 for (i = 0; i < n; i++) {
 351                         e = entry + i;
 352                         extended_entry_extract(tx + i, e, NULL, 0);
 353                 }
 354
 355                 /*
 356                  * A tree may have "t-2" at the current location even
 357                  * though it may have "t" that is a subtree behind it,
 358                  * and another tree may return "t".  We want to grab
 359                  * all "t" from all trees to match in such a case.
 360                  */
 361                 for (i = 0; i < n; i++) {
 362                         e = entry + i;
 363                         if (!e->path)
 364                                 continue;
 365                         len = tree_entry_len(e);
 366                         if (!first) {
 367                                 first = e->path;
 368                                 first_len = len;
 369                                 continue;
 370                         }
 371                         if (name_compare(e->path, len, first, first_len) < 0) {
 372                                 first = e->path;
 373                                 first_len = len;
 374                         }
 375                 }
 376
 377                 if (first) {
 378                         for (i = 0; i < n; i++) {
 379                                 e = entry + i;
 380                                 extended_entry_extract(tx + i, e, first, first_len);
 381                                 /* Cull the ones that are not the earliest */
 382                                 if (!e->path)
 383                                         continue;
 384                                 len = tree_entry_len(e);
 385                                 if (name_compare(e->path, len, first, first_len))
 386                                         entry_clear(e);
 387                         }
 388                 }
 389
 390                 /* Now we have in entry[i] the earliest name from the trees */
 391                 mask = 0;
 392                 dirmask = 0;
 393                 for (i = 0; i < n; i++) {
 394                         if (!entry[i].path)
 395                                 continue;
 396                         mask |= 1ul << i;
 397                         if (S_ISDIR(entry[i].mode))
 398                                 dirmask |= 1ul << i;
 399                         e = &entry[i];
 400                 }
 401                 if (!mask)
 402                         break;
 403                 interesting = prune_traversal(e, info, &base, interesting);
 404                 if (interesting < 0)
 405                         break;
 406                 if (interesting) {
 407                         trees_used = info->fn(n, mask, dirmask, entry, info);
 408                         if (trees_used < 0) {
 409                                 error = trees_used;
 410                                 if (!info->show_all_errors)
 411                                         break;
 412                         }
 413                         mask &= trees_used;
 414                 }
 415                 for (i = 0; i < n; i++)
 416                         if (mask & (1ul << i))
 417                                 update_extended_entry(tx + i, entry + i);
 418         }
 419         free(entry);
 420         for (i = 0; i < n; i++)
 421                 free_extended_entry(tx + i);
 422         free(tx);
 423         strbuf_release(&base);
 424         return error;
 425 }
 426
 427 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
 428 {
 429         int namelen = strlen(name);
 430         while (t->size) {
 431                 const char *entry;
 432                 const unsigned char *sha1;
 433                 int entrylen, cmp;
 434
 435                 sha1 = tree_entry_extract(t, &entry, mode);
 436                 entrylen = tree_entry_len(&t->entry);
 437                 update_tree_entry(t);
 438                 if (entrylen > namelen)
 439                         continue;
 440                 cmp = memcmp(name, entry, entrylen);
 441                 if (cmp > 0)
 442                         continue;
 443                 if (cmp < 0)
 444                         break;
 445                 if (entrylen == namelen) {
 446                         hashcpy(result, sha1);
 447                         return 0;
 448                 }
 449                 if (name[entrylen] != '/')
 450                         continue;
 451                 if (!S_ISDIR(*mode))
 452                         break;
 453                 if (++entrylen == namelen) {
 454                         hashcpy(result, sha1);
 455                         return 0;
 456                 }
 457                 return get_tree_entry(sha1, name + entrylen, result, mode);
 458         }
 459         return -1;
 460 }
 461
 462 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
 463 {
 464         int retval;
 465         void *tree;
 466         unsigned long size;
 467         unsigned char root[20];
 468
 469         tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
 470         if (!tree)
 471                 return -1;
 472
 473         if (name[0] == '\0') {
 474                 hashcpy(sha1, root);
 475                 free(tree);
 476                 return 0;
 477         }
 478
 479         if (!size) {
 480                 retval = -1;
 481         } else {
 482                 struct tree_desc t;
 483                 init_tree_desc(&t, tree, size);
 484                 retval = find_tree_entry(&t, name, sha1, mode);
 485         }
 486         free(tree);
 487         return retval;
 488 }
 489
 490 static int match_entry(const struct name_entry *entry, int pathlen,
 491                        const char *match, int matchlen,
 492                        enum interesting *never_interesting)
 493 {
 494         int m = -1; /* signals that we haven't called strncmp() */
 495
 496         if (*never_interesting != entry_not_interesting) {
 497                 /*
 498                  * We have not seen any match that sorts later
 499                  * than the current path.
 500                  */
 501
 502                 /*
 503                  * Does match sort strictly earlier than path
 504                  * with their common parts?
 505                  */
 506                 m = strncmp(match, entry->path,
 507                             (matchlen < pathlen) ? matchlen : pathlen);
 508                 if (m < 0)
 509                         return 0;
 510
 511                 /*
 512                  * If we come here even once, that means there is at
 513                  * least one pathspec that would sort equal to or
 514                  * later than the path we are currently looking at.
 515                  * In other words, if we have never reached this point
 516                  * after iterating all pathspecs, it means all
 517                  * pathspecs are either outside of base, or inside the
 518                  * base but sorts strictly earlier than the current
 519                  * one.  In either case, they will never match the
 520                  * subsequent entries.  In such a case, we initialized
 521                  * the variable to -1 and that is what will be
 522                  * returned, allowing the caller to terminate early.
 523                  */
 524                 *never_interesting = entry_not_interesting;
 525         }
 526
 527         if (pathlen > matchlen)
 528                 return 0;
 529
 530         if (matchlen > pathlen) {
 531                 if (match[pathlen] != '/')
 532                         return 0;
 533                 if (!S_ISDIR(entry->mode))
 534                         return 0;
 535         }
 536
 537         if (m == -1)
 538                 /*
 539                  * we cheated and did not do strncmp(), so we do
 540                  * that here.
 541                  */
 542                 m = strncmp(match, entry->path, pathlen);
 543
 544         /*
 545          * If common part matched earlier then it is a hit,
 546          * because we rejected the case where path is not a
 547          * leading directory and is shorter than match.
 548          */
 549         if (!m)
 550                 return 1;
 551
 552         return 0;
 553 }
 554
 555 static int match_dir_prefix(const char *base,
 556                             const char *match, int matchlen)
 557 {
 558         if (strncmp(base, match, matchlen))
 559                 return 0;
 560
 561         /*
 562          * If the base is a subdirectory of a path which
 563          * was specified, all of them are interesting.
 564          */
 565         if (!matchlen ||
 566             base[matchlen] == '/' ||
 567             match[matchlen - 1] == '/')
 568                 return 1;
 569
 570         /* Just a random prefix match */
 571         return 0;
 572 }
 573
 574 /*
 575  * Perform matching on the leading non-wildcard part of
 576  * pathspec. item->nowildcard_len must be greater than zero. Return
 577  * non-zero if base is matched.
 578  */
 579 static int match_wildcard_base(const struct pathspec_item *item,
 580                                const char *base, int baselen,
 581                                int *matched)
 582 {
 583         const char *match = item->match;
 584         /* the wildcard part is not considered in this function */
 585         int matchlen = item->nowildcard_len;
 586
 587         if (baselen) {
 588                 int dirlen;
 589                 /*
 590                  * Return early if base is longer than the
 591                  * non-wildcard part but it does not match.
 592                  */
 593                 if (baselen >= matchlen) {
 594                         *matched = matchlen;
 595                         return !strncmp(base, match, matchlen);
 596                 }
 597
 598                 dirlen = matchlen;
 599                 while (dirlen && match[dirlen - 1] != '/')
 600                         dirlen--;
 601
 602                 /*
 603                  * Return early if base is shorter than the
 604                  * non-wildcard part but it does not match. Note that
 605                  * base ends with '/' so we are sure it really matches
 606                  * directory
 607                  */
 608                 if (strncmp(base, match, baselen))
 609                         return 0;
 610                 *matched = baselen;
 611         } else
 612                 *matched = 0;
 613         /*
 614          * we could have checked entry against the non-wildcard part
 615          * that is not in base and does similar never_interesting
 616          * optimization as in match_entry. For now just be happy with
 617          * base comparison.
 618          */
 619         return entry_interesting;
 620 }
 621
 622 /*
 623  * Is a tree entry interesting given the pathspec we have?
 624  *
 625  * Pre-condition: either baselen == base_offset (i.e. empty path)
 626  * or base[baselen-1] == '/' (i.e. with trailing slash).
 627  */
 628 enum interesting tree_entry_interesting(const struct name_entry *entry,
 629                                         struct strbuf *base, int base_offset,
 630                                         const struct pathspec *ps)
 631 {
 632         int i;
 633         int pathlen, baselen = base->len - base_offset;
 634         enum interesting never_interesting = ps->has_wildcard ?
 635                 entry_not_interesting : all_entries_not_interesting;
 636
 637         if (!ps->nr) {
 638                 if (!ps->recursive || ps->max_depth == -1)
 639                         return all_entries_interesting;
 640                 return within_depth(base->buf + base_offset, baselen,
 641                                     !!S_ISDIR(entry->mode),
 642                                     ps->max_depth) ?
 643                         entry_interesting : entry_not_interesting;
 644         }
 645
 646         pathlen = tree_entry_len(entry);
 647
 648         for (i = ps->nr - 1; i >= 0; i--) {
 649                 const struct pathspec_item *item = ps->items+i;
 650                 const char *match = item->match;
 651                 const char *base_str = base->buf + base_offset;
 652                 int matchlen = item->len, matched = 0;
 653
 654                 if (baselen >= matchlen) {
 655                         /* If it doesn't match, move along... */
 656                         if (!match_dir_prefix(base_str, match, matchlen))
 657                                 goto match_wildcards;
 658
 659                         if (!ps->recursive || ps->max_depth == -1)
 660                                 return all_entries_interesting;
 661
 662                         return within_depth(base_str + matchlen + 1,
 663                                             baselen - matchlen - 1,
 664                                             !!S_ISDIR(entry->mode),
 665                                             ps->max_depth) ?
 666                                 entry_interesting : entry_not_interesting;
 667                 }
 668
 669                 /* Either there must be no base, or the base must match. */
 670                 if (baselen == 0 || !strncmp(base_str, match, baselen)) {
 671                         if (match_entry(entry, pathlen,
 672                                         match + baselen, matchlen - baselen,
 673                                         &never_interesting))
 674                                 return entry_interesting;
 675
 676                         if (item->nowildcard_len < item->len) {
 677                                 if (!git_fnmatch(match + baselen, entry->path,
 678                                                  item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
 679                                                  item->nowildcard_len - baselen))
 680                                         return entry_interesting;
 681
 682                                 /*
 683                                  * Match all directories. We'll try to
 684                                  * match files later on.
 685                                  */
 686                                 if (ps->recursive && S_ISDIR(entry->mode))
 687                                         return entry_interesting;
 688                         }
 689
 690                         continue;
 691                 }
 692
 693 match_wildcards:
 694                 if (item->nowildcard_len == item->len)
 695                         continue;
 696
 697                 if (item->nowildcard_len &&
 698                     !match_wildcard_base(item, base_str, baselen, &matched))
 699                         continue;
 700
 701                 /*
 702                  * Concatenate base and entry->path into one and do
 703                  * fnmatch() on it.
 704                  *
 705                  * While we could avoid concatenation in certain cases
 706                  * [1], which saves a memcpy and potentially a
 707                  * realloc, it turns out not worth it. Measurement on
 708                  * linux-2.6 does not show any clear improvements,
 709                  * partly because of the nowildcard_len optimization
 710                  * in git_fnmatch(). Avoid micro-optimizations here.
 711                  *
 712                  * [1] if match_wildcard_base() says the base
 713                  * directory is already matched, we only need to match
 714                  * the rest, which is shorter so _in theory_ faster.
 715                  */
 716
 717                 strbuf_add(base, entry->path, pathlen);
 718
 719                 if (!git_fnmatch(match, base->buf + base_offset,
 720                                  item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
 721                                  item->nowildcard_len)) {
 722                         strbuf_setlen(base, base_offset + baselen);
 723                         return entry_interesting;
 724                 }
 725                 strbuf_setlen(base, base_offset + baselen);
 726
 727                 /*
 728                  * Match all directories. We'll try to match files
 729                  * later on.
 730                  * max_depth is ignored but we may consider support it
 731                  * in future, see
 732                  * http://thread.gmane.org/gmane.comp.version-control.git/163757/focus=163840
 733                  */
 734                 if (ps->recursive && S_ISDIR(entry->mode))
 735                         return entry_interesting;
 736         }
 737         return never_interesting; /* No matches */
 738 }