tree-walk.c

   1 #include "cache.h"
   2 #include "tree-walk.h"
   3 #include "unpack-trees.h"
   4 #include "dir.h"
   5 #include "object-store.h"
   6 #include "tree.h"
   7 #include "pathspec.h"
   8
   9 static const char *get_mode(const char *str, unsigned int *modep)
  10 {
  11         unsigned char c;
  12         unsigned int mode = 0;
  13
  14         if (*str == ' ')
  15                 return NULL;
  16
  17         while ((c = *str++) != ' ') {
  18                 if (c < '0' || c > '7')
  19                         return NULL;
  20                 mode = (mode << 3) + (c - '0');
  21         }
  22         *modep = mode;
  23         return str;
  24 }
  25
  26 static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size, struct strbuf *err)
  27 {
  28         const char *path;
  29         unsigned int mode, len;
  30         const unsigned hashsz = the_hash_algo->rawsz;
  31
  32         if (size < hashsz + 3 || buf[size - (hashsz + 1)]) {
  33                 strbuf_addstr(err, _("too-short tree object"));
  34                 return -1;
  35         }
  36
  37         path = get_mode(buf, &mode);
  38         if (!path) {
  39                 strbuf_addstr(err, _("malformed mode in tree entry"));
  40                 return -1;
  41         }
  42         if (!*path) {
  43                 strbuf_addstr(err, _("empty filename in tree entry"));
  44                 return -1;
  45         }
  46 #ifdef GIT_WINDOWS_NATIVE
  47         if (protect_ntfs && strchr(path, '\\')) {
  48                 strbuf_addf(err, _("filename in tree entry contains backslash: '%s'"), path);
  49                 return -1;
  50         }
  51 #endif
  52         len = strlen(path) + 1;
  53
  54         /* Initialize the descriptor entry */
  55         desc->entry.path = path;
  56         desc->entry.mode = canon_mode(mode);
  57         desc->entry.pathlen = len - 1;
  58         hashcpy(desc->entry.oid.hash, (const unsigned char *)path + len);
  59
  60         return 0;
  61 }
  62
  63 static int init_tree_desc_internal(struct tree_desc *desc, const void *buffer, unsigned long size, struct strbuf *err)
  64 {
  65         desc->buffer = buffer;
  66         desc->size = size;
  67         if (size)
  68                 return decode_tree_entry(desc, buffer, size, err);
  69         return 0;
  70 }
  71
  72 void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
  73 {
  74         struct strbuf err = STRBUF_INIT;
  75         if (init_tree_desc_internal(desc, buffer, size, &err))
  76                 die("%s", err.buf);
  77         strbuf_release(&err);
  78 }
  79
  80 int init_tree_desc_gently(struct tree_desc *desc, const void *buffer, unsigned long size)
  81 {
  82         struct strbuf err = STRBUF_INIT;
  83         int result = init_tree_desc_internal(desc, buffer, size, &err);
  84         if (result)
  85                 error("%s", err.buf);
  86         strbuf_release(&err);
  87         return result;
  88 }
  89
  90 void *fill_tree_descriptor(struct repository *r,
  91                            struct tree_desc *desc,
  92                            const struct object_id *oid)
  93 {
  94         unsigned long size = 0;
  95         void *buf = NULL;
  96
  97         if (oid) {
  98                 buf = read_object_with_reference(r, oid, tree_type, &size, NULL);
  99                 if (!buf)
 100                         die("unable to read tree %s", oid_to_hex(oid));
 101         }
 102         init_tree_desc(desc, buf, size);
 103         return buf;
 104 }
 105
 106 static void entry_clear(struct name_entry *a)
 107 {
 108         memset(a, 0, sizeof(*a));
 109 }
 110
 111 static void entry_extract(struct tree_desc *t, struct name_entry *a)
 112 {
 113         *a = t->entry;
 114 }
 115
 116 static int update_tree_entry_internal(struct tree_desc *desc, struct strbuf *err)
 117 {
 118         const void *buf = desc->buffer;
 119         const unsigned char *end = (const unsigned char *)desc->entry.path + desc->entry.pathlen + 1 + the_hash_algo->rawsz;
 120         unsigned long size = desc->size;
 121         unsigned long len = end - (const unsigned char *)buf;
 122
 123         if (size < len)
 124                 die(_("too-short tree file"));
 125         buf = end;
 126         size -= len;
 127         desc->buffer = buf;
 128         desc->size = size;
 129         if (size)
 130                 return decode_tree_entry(desc, buf, size, err);
 131         return 0;
 132 }
 133
 134 void update_tree_entry(struct tree_desc *desc)
 135 {
 136         struct strbuf err = STRBUF_INIT;
 137         if (update_tree_entry_internal(desc, &err))
 138                 die("%s", err.buf);
 139         strbuf_release(&err);
 140 }
 141
 142 int update_tree_entry_gently(struct tree_desc *desc)
 143 {
 144         struct strbuf err = STRBUF_INIT;
 145         if (update_tree_entry_internal(desc, &err)) {
 146                 error("%s", err.buf);
 147                 strbuf_release(&err);
 148                 /* Stop processing this tree after error */
 149                 desc->size = 0;
 150                 return -1;
 151         }
 152         strbuf_release(&err);
 153         return 0;
 154 }
 155
 156 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
 157 {
 158         if (!desc->size)
 159                 return 0;
 160
 161         *entry = desc->entry;
 162         update_tree_entry(desc);
 163         return 1;
 164 }
 165
 166 int tree_entry_gently(struct tree_desc *desc, struct name_entry *entry)
 167 {
 168         if (!desc->size)
 169                 return 0;
 170
 171         *entry = desc->entry;
 172         if (update_tree_entry_gently(desc))
 173                 return 0;
 174         return 1;
 175 }
 176
 177 void setup_traverse_info(struct traverse_info *info, const char *base)
 178 {
 179         int pathlen = strlen(base);
 180         static struct traverse_info dummy;
 181
 182         memset(info, 0, sizeof(*info));
 183         if (pathlen && base[pathlen-1] == '/')
 184                 pathlen--;
 185         info->pathlen = pathlen ? pathlen + 1 : 0;
 186         info->name.path = base;
 187         info->name.pathlen = pathlen;
 188         if (pathlen) {
 189                 hashcpy(info->name.oid.hash, (const unsigned char *)base + pathlen + 1);
 190                 info->prev = &dummy;
 191         }
 192 }
 193
 194 char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
 195 {
 196         int len = tree_entry_len(n);
 197         int pathlen = info->pathlen;
 198
 199         path[pathlen + len] = 0;
 200         for (;;) {
 201                 memcpy(path + pathlen, n->path, len);
 202                 if (!pathlen)
 203                         break;
 204                 path[--pathlen] = '/';
 205                 n = &info->name;
 206                 len = tree_entry_len(n);
 207                 info = info->prev;
 208                 pathlen -= len;
 209         }
 210         return path;
 211 }
 212
 213 struct tree_desc_skip {
 214         struct tree_desc_skip *prev;
 215         const void *ptr;
 216 };
 217
 218 struct tree_desc_x {
 219         struct tree_desc d;
 220         struct tree_desc_skip *skip;
 221 };
 222
 223 static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
 224 {
 225         /*
 226          * The caller wants to pick *a* from a tree or nothing.
 227          * We are looking at *b* in a tree.
 228          *
 229          * (0) If a and b are the same name, we are trivially happy.
 230          *
 231          * There are three possibilities where *a* could be hiding
 232          * behind *b*.
 233          *
 234          * (1) *a* == "t",   *b* == "ab"  i.e. *b* sorts earlier than *a* no
 235          *                                matter what.
 236          * (2) *a* == "t",   *b* == "t-2" and "t" is a subtree in the tree;
 237          * (3) *a* == "t-2", *b* == "t"   and "t-2" is a blob in the tree.
 238          *
 239          * Otherwise we know *a* won't appear in the tree without
 240          * scanning further.
 241          */
 242
 243         int cmp = name_compare(a, a_len, b, b_len);
 244
 245         /* Most common case first -- reading sync'd trees */
 246         if (!cmp)
 247                 return cmp;
 248
 249         if (0 < cmp) {
 250                 /* a comes after b; it does not matter if it is case (3)
 251                 if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
 252                         return 1;
 253                 */
 254                 return 1; /* keep looking */
 255         }
 256
 257         /* b comes after a; are we looking at case (2)? */
 258         if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
 259                 return 1; /* keep looking */
 260
 261         return -1; /* a cannot appear in the tree */
 262 }
 263
 264 /*
 265  * From the extended tree_desc, extract the first name entry, while
 266  * paying attention to the candidate "first" name.  Most importantly,
 267  * when looking for an entry, if there are entries that sorts earlier
 268  * in the tree object representation than that name, skip them and
 269  * process the named entry first.  We will remember that we haven't
 270  * processed the first entry yet, and in the later call skip the
 271  * entry we processed early when update_extended_entry() is called.
 272  *
 273  * E.g. if the underlying tree object has these entries:
 274  *
 275  *    blob    "t-1"
 276  *    blob    "t-2"
 277  *    tree    "t"
 278  *    blob    "t=1"
 279  *
 280  * and the "first" asks for "t", remember that we still need to
 281  * process "t-1" and "t-2" but extract "t".  After processing the
 282  * entry "t" from this call, the caller will let us know by calling
 283  * update_extended_entry() that we can remember "t" has been processed
 284  * already.
 285  */
 286
 287 static void extended_entry_extract(struct tree_desc_x *t,
 288                                    struct name_entry *a,
 289                                    const char *first,
 290                                    int first_len)
 291 {
 292         const char *path;
 293         int len;
 294         struct tree_desc probe;
 295         struct tree_desc_skip *skip;
 296
 297         /*
 298          * Extract the first entry from the tree_desc, but skip the
 299          * ones that we already returned in earlier rounds.
 300          */
 301         while (1) {
 302                 if (!t->d.size) {
 303                         entry_clear(a);
 304                         break; /* not found */
 305                 }
 306                 entry_extract(&t->d, a);
 307                 for (skip = t->skip; skip; skip = skip->prev)
 308                         if (a->path == skip->ptr)
 309                                 break; /* found */
 310                 if (!skip)
 311                         break;
 312                 /* We have processed this entry already. */
 313                 update_tree_entry(&t->d);
 314         }
 315
 316         if (!first || !a->path)
 317                 return;
 318
 319         /*
 320          * The caller wants "first" from this tree, or nothing.
 321          */
 322         path = a->path;
 323         len = tree_entry_len(a);
 324         switch (check_entry_match(first, first_len, path, len)) {
 325         case -1:
 326                 entry_clear(a);
 327         case 0:
 328                 return;
 329         default:
 330                 break;
 331         }
 332
 333         /*
 334          * We need to look-ahead -- we suspect that a subtree whose
 335          * name is "first" may be hiding behind the current entry "path".
 336          */
 337         probe = t->d;
 338         while (probe.size) {
 339                 entry_extract(&probe, a);
 340                 path = a->path;
 341                 len = tree_entry_len(a);
 342                 switch (check_entry_match(first, first_len, path, len)) {
 343                 case -1:
 344                         entry_clear(a);
 345                 case 0:
 346                         return;
 347                 default:
 348                         update_tree_entry(&probe);
 349                         break;
 350                 }
 351                 /* keep looking */
 352         }
 353         entry_clear(a);
 354 }
 355
 356 static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
 357 {
 358         if (t->d.entry.path == a->path) {
 359                 update_tree_entry(&t->d);
 360         } else {
 361                 /* we have returned this entry early */
 362                 struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
 363                 skip->ptr = a->path;
 364                 skip->prev = t->skip;
 365                 t->skip = skip;
 366         }
 367 }
 368
 369 static void free_extended_entry(struct tree_desc_x *t)
 370 {
 371         struct tree_desc_skip *p, *s;
 372
 373         for (s = t->skip; s; s = p) {
 374                 p = s->prev;
 375                 free(s);
 376         }
 377 }
 378
 379 static inline int prune_traversal(struct index_state *istate,
 380                                   struct name_entry *e,
 381                                   struct traverse_info *info,
 382                                   struct strbuf *base,
 383                                   int still_interesting)
 384 {
 385         if (!info->pathspec || still_interesting == 2)
 386                 return 2;
 387         if (still_interesting < 0)
 388                 return still_interesting;
 389         return tree_entry_interesting(istate, e, base,
 390                                       0, info->pathspec);
 391 }
 392
 393 int traverse_trees(struct index_state *istate,
 394                    int n, struct tree_desc *t,
 395                    struct traverse_info *info)
 396 {
 397         int error = 0;
 398         struct name_entry *entry = xmalloc(n*sizeof(*entry));
 399         int i;
 400         struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
 401         struct strbuf base = STRBUF_INIT;
 402         int interesting = 1;
 403         char *traverse_path;
 404
 405         for (i = 0; i < n; i++)
 406                 tx[i].d = t[i];
 407
 408         if (info->prev) {
 409                 strbuf_grow(&base, info->pathlen);
 410                 make_traverse_path(base.buf, info->prev, &info->name);
 411                 base.buf[info->pathlen-1] = '/';
 412                 strbuf_setlen(&base, info->pathlen);
 413                 traverse_path = xstrndup(base.buf, info->pathlen);
 414         } else {
 415                 traverse_path = xstrndup(info->name.path, info->pathlen);
 416         }
 417         info->traverse_path = traverse_path;
 418         for (;;) {
 419                 int trees_used;
 420                 unsigned long mask, dirmask;
 421                 const char *first = NULL;
 422                 int first_len = 0;
 423                 struct name_entry *e = NULL;
 424                 int len;
 425
 426                 for (i = 0; i < n; i++) {
 427                         e = entry + i;
 428                         extended_entry_extract(tx + i, e, NULL, 0);
 429                 }
 430
 431                 /*
 432                  * A tree may have "t-2" at the current location even
 433                  * though it may have "t" that is a subtree behind it,
 434                  * and another tree may return "t".  We want to grab
 435                  * all "t" from all trees to match in such a case.
 436                  */
 437                 for (i = 0; i < n; i++) {
 438                         e = entry + i;
 439                         if (!e->path)
 440                                 continue;
 441                         len = tree_entry_len(e);
 442                         if (!first) {
 443                                 first = e->path;
 444                                 first_len = len;
 445                                 continue;
 446                         }
 447                         if (name_compare(e->path, len, first, first_len) < 0) {
 448                                 first = e->path;
 449                                 first_len = len;
 450                         }
 451                 }
 452
 453                 if (first) {
 454                         for (i = 0; i < n; i++) {
 455                                 e = entry + i;
 456                                 extended_entry_extract(tx + i, e, first, first_len);
 457                                 /* Cull the ones that are not the earliest */
 458                                 if (!e->path)
 459                                         continue;
 460                                 len = tree_entry_len(e);
 461                                 if (name_compare(e->path, len, first, first_len))
 462                                         entry_clear(e);
 463                         }
 464                 }
 465
 466                 /* Now we have in entry[i] the earliest name from the trees */
 467                 mask = 0;
 468                 dirmask = 0;
 469                 for (i = 0; i < n; i++) {
 470                         if (!entry[i].path)
 471                                 continue;
 472                         mask |= 1ul << i;
 473                         if (S_ISDIR(entry[i].mode))
 474                                 dirmask |= 1ul << i;
 475                         e = &entry[i];
 476                 }
 477                 if (!mask)
 478                         break;
 479                 interesting = prune_traversal(istate, e, info, &base, interesting);
 480                 if (interesting < 0)
 481                         break;
 482                 if (interesting) {
 483                         trees_used = info->fn(n, mask, dirmask, entry, info);
 484                         if (trees_used < 0) {
 485                                 error = trees_used;
 486                                 if (!info->show_all_errors)
 487                                         break;
 488                         }
 489                         mask &= trees_used;
 490                 }
 491                 for (i = 0; i < n; i++)
 492                         if (mask & (1ul << i))
 493                                 update_extended_entry(tx + i, entry + i);
 494         }
 495         free(entry);
 496         for (i = 0; i < n; i++)
 497                 free_extended_entry(tx + i);
 498         free(tx);
 499         free(traverse_path);
 500         info->traverse_path = NULL;
 501         strbuf_release(&base);
 502         return error;
 503 }
 504
 505 struct dir_state {
 506         void *tree;
 507         unsigned long size;
 508         struct object_id oid;
 509 };
 510
 511 static int find_tree_entry(struct repository *r, struct tree_desc *t,
 512                            const char *name, struct object_id *result,
 513                            unsigned short *mode)
 514 {
 515         int namelen = strlen(name);
 516         while (t->size) {
 517                 const char *entry;
 518                 struct object_id oid;
 519                 int entrylen, cmp;
 520
 521                 oidcpy(&oid, tree_entry_extract(t, &entry, mode));
 522                 entrylen = tree_entry_len(&t->entry);
 523                 update_tree_entry(t);
 524                 if (entrylen > namelen)
 525                         continue;
 526                 cmp = memcmp(name, entry, entrylen);
 527                 if (cmp > 0)
 528                         continue;
 529                 if (cmp < 0)
 530                         break;
 531                 if (entrylen == namelen) {
 532                         oidcpy(result, &oid);
 533                         return 0;
 534                 }
 535                 if (name[entrylen] != '/')
 536                         continue;
 537                 if (!S_ISDIR(*mode))
 538                         break;
 539                 if (++entrylen == namelen) {
 540                         oidcpy(result, &oid);
 541                         return 0;
 542                 }
 543                 return get_tree_entry(r, &oid, name + entrylen, result, mode);
 544         }
 545         return -1;
 546 }
 547
 548 int get_tree_entry(struct repository *r,
 549                    const struct object_id *tree_oid,
 550                    const char *name,
 551                    struct object_id *oid,
 552                    unsigned short *mode)
 553 {
 554         int retval;
 555         void *tree;
 556         unsigned long size;
 557         struct object_id root;
 558
 559         tree = read_object_with_reference(r, tree_oid, tree_type, &size, &root);
 560         if (!tree)
 561                 return -1;
 562
 563         if (name[0] == '\0') {
 564                 oidcpy(oid, &root);
 565                 free(tree);
 566                 return 0;
 567         }
 568
 569         if (!size) {
 570                 retval = -1;
 571         } else {
 572                 struct tree_desc t;
 573                 init_tree_desc(&t, tree, size);
 574                 retval = find_tree_entry(r, &t, name, oid, mode);
 575         }
 576         free(tree);
 577         return retval;
 578 }
 579
 580 /*
 581  * This is Linux's built-in max for the number of symlinks to follow.
 582  * That limit, of course, does not affect git, but it's a reasonable
 583  * choice.
 584  */
 585 #define GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS 40
 586
 587 /**
 588  * Find a tree entry by following symlinks in tree_sha (which is
 589  * assumed to be the root of the repository).  In the event that a
 590  * symlink points outside the repository (e.g. a link to /foo or a
 591  * root-level link to ../foo), the portion of the link which is
 592  * outside the repository will be returned in result_path, and *mode
 593  * will be set to 0.  It is assumed that result_path is uninitialized.
 594  * If there are no symlinks, or the end result of the symlink chain
 595  * points to an object inside the repository, result will be filled in
 596  * with the sha1 of the found object, and *mode will hold the mode of
 597  * the object.
 598  *
 599  * See the code for enum get_oid_result for a description of
 600  * the return values.
 601  */
 602 enum get_oid_result get_tree_entry_follow_symlinks(struct repository *r,
 603                 struct object_id *tree_oid, const char *name,
 604                 struct object_id *result, struct strbuf *result_path,
 605                 unsigned short *mode)
 606 {
 607         int retval = MISSING_OBJECT;
 608         struct dir_state *parents = NULL;
 609         size_t parents_alloc = 0;
 610         size_t i, parents_nr = 0;
 611         struct object_id current_tree_oid;
 612         struct strbuf namebuf = STRBUF_INIT;
 613         struct tree_desc t;
 614         int follows_remaining = GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS;
 615
 616         init_tree_desc(&t, NULL, 0UL);
 617         strbuf_addstr(&namebuf, name);
 618         oidcpy(&current_tree_oid, tree_oid);
 619
 620         while (1) {
 621                 int find_result;
 622                 char *first_slash;
 623                 char *remainder = NULL;
 624
 625                 if (!t.buffer) {
 626                         void *tree;
 627                         struct object_id root;
 628                         unsigned long size;
 629                         tree = read_object_with_reference(r,
 630                                                           &current_tree_oid,
 631                                                           tree_type, &size,
 632                                                           &root);
 633                         if (!tree)
 634                                 goto done;
 635
 636                         ALLOC_GROW(parents, parents_nr + 1, parents_alloc);
 637                         parents[parents_nr].tree = tree;
 638                         parents[parents_nr].size = size;
 639                         oidcpy(&parents[parents_nr].oid, &root);
 640                         parents_nr++;
 641
 642                         if (namebuf.buf[0] == '\0') {
 643                                 oidcpy(result, &root);
 644                                 retval = FOUND;
 645                                 goto done;
 646                         }
 647
 648                         if (!size)
 649                                 goto done;
 650
 651                         /* descend */
 652                         init_tree_desc(&t, tree, size);
 653                 }
 654
 655                 /* Handle symlinks to e.g. a//b by removing leading slashes */
 656                 while (namebuf.buf[0] == '/') {
 657                         strbuf_remove(&namebuf, 0, 1);
 658                 }
 659
 660                 /* Split namebuf into a first component and a remainder */
 661                 if ((first_slash = strchr(namebuf.buf, '/'))) {
 662                         *first_slash = 0;
 663                         remainder = first_slash + 1;
 664                 }
 665
 666                 if (!strcmp(namebuf.buf, "..")) {
 667                         struct dir_state *parent;
 668                         /*
 669                          * We could end up with .. in the namebuf if it
 670                          * appears in a symlink.
 671                          */
 672
 673                         if (parents_nr == 1) {
 674                                 if (remainder)
 675                                         *first_slash = '/';
 676                                 strbuf_add(result_path, namebuf.buf,
 677                                            namebuf.len);
 678                                 *mode = 0;
 679                                 retval = FOUND;
 680                                 goto done;
 681                         }
 682                         parent = &parents[parents_nr - 1];
 683                         free(parent->tree);
 684                         parents_nr--;
 685                         parent = &parents[parents_nr - 1];
 686                         init_tree_desc(&t, parent->tree, parent->size);
 687                         strbuf_remove(&namebuf, 0, remainder ? 3 : 2);
 688                         continue;
 689                 }
 690
 691                 /* We could end up here via a symlink to dir/.. */
 692                 if (namebuf.buf[0] == '\0') {
 693                         oidcpy(result, &parents[parents_nr - 1].oid);
 694                         retval = FOUND;
 695                         goto done;
 696                 }
 697
 698                 /* Look up the first (or only) path component in the tree. */
 699                 find_result = find_tree_entry(r, &t, namebuf.buf,
 700                                               &current_tree_oid, mode);
 701                 if (find_result) {
 702                         goto done;
 703                 }
 704
 705                 if (S_ISDIR(*mode)) {
 706                         if (!remainder) {
 707                                 oidcpy(result, &current_tree_oid);
 708                                 retval = FOUND;
 709                                 goto done;
 710                         }
 711                         /* Descend the tree */
 712                         t.buffer = NULL;
 713                         strbuf_remove(&namebuf, 0,
 714                                       1 + first_slash - namebuf.buf);
 715                 } else if (S_ISREG(*mode)) {
 716                         if (!remainder) {
 717                                 oidcpy(result, &current_tree_oid);
 718                                 retval = FOUND;
 719                         } else {
 720                                 retval = NOT_DIR;
 721                         }
 722                         goto done;
 723                 } else if (S_ISLNK(*mode)) {
 724                         /* Follow a symlink */
 725                         unsigned long link_len;
 726                         size_t len;
 727                         char *contents, *contents_start;
 728                         struct dir_state *parent;
 729                         enum object_type type;
 730
 731                         if (follows_remaining-- == 0) {
 732                                 /* Too many symlinks followed */
 733                                 retval = SYMLINK_LOOP;
 734                                 goto done;
 735                         }
 736
 737                         /*
 738                          * At this point, we have followed at a least
 739                          * one symlink, so on error we need to report this.
 740                          */
 741                         retval = DANGLING_SYMLINK;
 742
 743                         contents = repo_read_object_file(r,
 744                                                     &current_tree_oid, &type,
 745                                                     &link_len);
 746
 747                         if (!contents)
 748                                 goto done;
 749
 750                         if (contents[0] == '/') {
 751                                 strbuf_addstr(result_path, contents);
 752                                 free(contents);
 753                                 *mode = 0;
 754                                 retval = FOUND;
 755                                 goto done;
 756                         }
 757
 758                         if (remainder)
 759                                 len = first_slash - namebuf.buf;
 760                         else
 761                                 len = namebuf.len;
 762
 763                         contents_start = contents;
 764
 765                         parent = &parents[parents_nr - 1];
 766                         init_tree_desc(&t, parent->tree, parent->size);
 767                         strbuf_splice(&namebuf, 0, len,
 768                                       contents_start, link_len);
 769                         if (remainder)
 770                                 namebuf.buf[link_len] = '/';
 771                         free(contents);
 772                 }
 773         }
 774 done:
 775         for (i = 0; i < parents_nr; i++)
 776                 free(parents[i].tree);
 777         free(parents);
 778
 779         strbuf_release(&namebuf);
 780         return retval;
 781 }
 782
 783 static int match_entry(const struct pathspec_item *item,
 784                        const struct name_entry *entry, int pathlen,
 785                        const char *match, int matchlen,
 786                        enum interesting *never_interesting)
 787 {
 788         int m = -1; /* signals that we haven't called strncmp() */
 789
 790         if (item->magic & PATHSPEC_ICASE)
 791                 /*
 792                  * "Never interesting" trick requires exact
 793                  * matching. We could do something clever with inexact
 794                  * matching, but it's trickier (and not to forget that
 795                  * strcasecmp is locale-dependent, at least in
 796                  * glibc). Just disable it for now. It can't be worse
 797                  * than the wildcard's codepath of '[Tt][Hi][Is][Ss]'
 798                  * pattern.
 799                  */
 800                 *never_interesting = entry_not_interesting;
 801         else if (*never_interesting != entry_not_interesting) {
 802                 /*
 803                  * We have not seen any match that sorts later
 804                  * than the current path.
 805                  */
 806
 807                 /*
 808                  * Does match sort strictly earlier than path
 809                  * with their common parts?
 810                  */
 811                 m = strncmp(match, entry->path,
 812                             (matchlen < pathlen) ? matchlen : pathlen);
 813                 if (m < 0)
 814                         return 0;
 815
 816                 /*
 817                  * If we come here even once, that means there is at
 818                  * least one pathspec that would sort equal to or
 819                  * later than the path we are currently looking at.
 820                  * In other words, if we have never reached this point
 821                  * after iterating all pathspecs, it means all
 822                  * pathspecs are either outside of base, or inside the
 823                  * base but sorts strictly earlier than the current
 824                  * one.  In either case, they will never match the
 825                  * subsequent entries.  In such a case, we initialized
 826                  * the variable to -1 and that is what will be
 827                  * returned, allowing the caller to terminate early.
 828                  */
 829                 *never_interesting = entry_not_interesting;
 830         }
 831
 832         if (pathlen > matchlen)
 833                 return 0;
 834
 835         if (matchlen > pathlen) {
 836                 if (match[pathlen] != '/')
 837                         return 0;
 838                 if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
 839                         return 0;
 840         }
 841
 842         if (m == -1)
 843                 /*
 844                  * we cheated and did not do strncmp(), so we do
 845                  * that here.
 846                  */
 847                 m = ps_strncmp(item, match, entry->path, pathlen);
 848
 849         /*
 850          * If common part matched earlier then it is a hit,
 851          * because we rejected the case where path is not a
 852          * leading directory and is shorter than match.
 853          */
 854         if (!m)
 855                 /*
 856                  * match_entry does not check if the prefix part is
 857                  * matched case-sensitively. If the entry is a
 858                  * directory and part of prefix, it'll be rematched
 859                  * eventually by basecmp with special treatment for
 860                  * the prefix.
 861                  */
 862                 return 1;
 863
 864         return 0;
 865 }
 866
 867 /* :(icase)-aware string compare */
 868 static int basecmp(const struct pathspec_item *item,
 869                    const char *base, const char *match, int len)
 870 {
 871         if (item->magic & PATHSPEC_ICASE) {
 872                 int ret, n = len > item->prefix ? item->prefix : len;
 873                 ret = strncmp(base, match, n);
 874                 if (ret)
 875                         return ret;
 876                 base += n;
 877                 match += n;
 878                 len -= n;
 879         }
 880         return ps_strncmp(item, base, match, len);
 881 }
 882
 883 static int match_dir_prefix(const struct pathspec_item *item,
 884                             const char *base,
 885                             const char *match, int matchlen)
 886 {
 887         if (basecmp(item, base, match, matchlen))
 888                 return 0;
 889
 890         /*
 891          * If the base is a subdirectory of a path which
 892          * was specified, all of them are interesting.
 893          */
 894         if (!matchlen ||
 895             base[matchlen] == '/' ||
 896             match[matchlen - 1] == '/')
 897                 return 1;
 898
 899         /* Just a random prefix match */
 900         return 0;
 901 }
 902
 903 /*
 904  * Perform matching on the leading non-wildcard part of
 905  * pathspec. item->nowildcard_len must be greater than zero. Return
 906  * non-zero if base is matched.
 907  */
 908 static int match_wildcard_base(const struct pathspec_item *item,
 909                                const char *base, int baselen,
 910                                int *matched)
 911 {
 912         const char *match = item->match;
 913         /* the wildcard part is not considered in this function */
 914         int matchlen = item->nowildcard_len;
 915
 916         if (baselen) {
 917                 int dirlen;
 918                 /*
 919                  * Return early if base is longer than the
 920                  * non-wildcard part but it does not match.
 921                  */
 922                 if (baselen >= matchlen) {
 923                         *matched = matchlen;
 924                         return !basecmp(item, base, match, matchlen);
 925                 }
 926
 927                 dirlen = matchlen;
 928                 while (dirlen && match[dirlen - 1] != '/')
 929                         dirlen--;
 930
 931                 /*
 932                  * Return early if base is shorter than the
 933                  * non-wildcard part but it does not match. Note that
 934                  * base ends with '/' so we are sure it really matches
 935                  * directory
 936                  */
 937                 if (basecmp(item, base, match, baselen))
 938                         return 0;
 939                 *matched = baselen;
 940         } else
 941                 *matched = 0;
 942         /*
 943          * we could have checked entry against the non-wildcard part
 944          * that is not in base and does similar never_interesting
 945          * optimization as in match_entry. For now just be happy with
 946          * base comparison.
 947          */
 948         return entry_interesting;
 949 }
 950
 951 /*
 952  * Is a tree entry interesting given the pathspec we have?
 953  *
 954  * Pre-condition: either baselen == base_offset (i.e. empty path)
 955  * or base[baselen-1] == '/' (i.e. with trailing slash).
 956  */
 957 static enum interesting do_match(struct index_state *istate,
 958                                  const struct name_entry *entry,
 959                                  struct strbuf *base, int base_offset,
 960                                  const struct pathspec *ps,
 961                                  int exclude)
 962 {
 963         int i;
 964         int pathlen, baselen = base->len - base_offset;
 965         enum interesting never_interesting = ps->has_wildcard ?
 966                 entry_not_interesting : all_entries_not_interesting;
 967
 968         GUARD_PATHSPEC(ps,
 969                        PATHSPEC_FROMTOP |
 970                        PATHSPEC_MAXDEPTH |
 971                        PATHSPEC_LITERAL |
 972                        PATHSPEC_GLOB |
 973                        PATHSPEC_ICASE |
 974                        PATHSPEC_EXCLUDE |
 975                        PATHSPEC_ATTR);
 976
 977         if (!ps->nr) {
 978                 if (!ps->recursive ||
 979                     !(ps->magic & PATHSPEC_MAXDEPTH) ||
 980                     ps->max_depth == -1)
 981                         return all_entries_interesting;
 982                 return within_depth(base->buf + base_offset, baselen,
 983                                     !!S_ISDIR(entry->mode),
 984                                     ps->max_depth) ?
 985                         entry_interesting : entry_not_interesting;
 986         }
 987
 988         pathlen = tree_entry_len(entry);
 989
 990         for (i = ps->nr - 1; i >= 0; i--) {
 991                 const struct pathspec_item *item = ps->items+i;
 992                 const char *match = item->match;
 993                 const char *base_str = base->buf + base_offset;
 994                 int matchlen = item->len, matched = 0;
 995
 996                 if ((!exclude &&   item->magic & PATHSPEC_EXCLUDE) ||
 997                     ( exclude && !(item->magic & PATHSPEC_EXCLUDE)))
 998                         continue;
 999
1000                 if (baselen >= matchlen) {
1001                         /* If it doesn't match, move along... */
1002                         if (!match_dir_prefix(item, base_str, match, matchlen))
1003                                 goto match_wildcards;
1004
1005                         if (!ps->recursive ||
1006                             !(ps->magic & PATHSPEC_MAXDEPTH) ||
1007                             ps->max_depth == -1) {
1008                                 if (!item->attr_match_nr)
1009                                         return all_entries_interesting;
1010                                 else
1011                                         goto interesting;
1012                         }
1013
1014                         if (within_depth(base_str + matchlen + 1,
1015                                          baselen - matchlen - 1,
1016                                          !!S_ISDIR(entry->mode),
1017                                          ps->max_depth))
1018                                 goto interesting;
1019                         else
1020                                 return entry_not_interesting;
1021                 }
1022
1023                 /* Either there must be no base, or the base must match. */
1024                 if (baselen == 0 || !basecmp(item, base_str, match, baselen)) {
1025                         if (match_entry(item, entry, pathlen,
1026                                         match + baselen, matchlen - baselen,
1027                                         &never_interesting))
1028                                 goto interesting;
1029
1030                         if (item->nowildcard_len < item->len) {
1031                                 if (!git_fnmatch(item, match + baselen, entry->path,
1032                                                  item->nowildcard_len - baselen))
1033                                         goto interesting;
1034
1035                                 /*
1036                                  * Match all directories. We'll try to
1037                                  * match files later on.
1038                                  */
1039                                 if (ps->recursive && S_ISDIR(entry->mode))
1040                                         return entry_interesting;
1041
1042                                 /*
1043                                  * When matching against submodules with
1044                                  * wildcard characters, ensure that the entry
1045                                  * at least matches up to the first wild
1046                                  * character.  More accurate matching can then
1047                                  * be performed in the submodule itself.
1048                                  */
1049                                 if (ps->recurse_submodules &&
1050                                     S_ISGITLINK(entry->mode) &&
1051                                     !ps_strncmp(item, match + baselen,
1052                                                 entry->path,
1053                                                 item->nowildcard_len - baselen))
1054                                         goto interesting;
1055                         }
1056
1057                         continue;
1058                 }
1059
1060 match_wildcards:
1061                 if (item->nowildcard_len == item->len)
1062                         continue;
1063
1064                 if (item->nowildcard_len &&
1065                     !match_wildcard_base(item, base_str, baselen, &matched))
1066                         continue;
1067
1068                 /*
1069                  * Concatenate base and entry->path into one and do
1070                  * fnmatch() on it.
1071                  *
1072                  * While we could avoid concatenation in certain cases
1073                  * [1], which saves a memcpy and potentially a
1074                  * realloc, it turns out not worth it. Measurement on
1075                  * linux-2.6 does not show any clear improvements,
1076                  * partly because of the nowildcard_len optimization
1077                  * in git_fnmatch(). Avoid micro-optimizations here.
1078                  *
1079                  * [1] if match_wildcard_base() says the base
1080                  * directory is already matched, we only need to match
1081                  * the rest, which is shorter so _in theory_ faster.
1082                  */
1083
1084                 strbuf_add(base, entry->path, pathlen);
1085
1086                 if (!git_fnmatch(item, match, base->buf + base_offset,
1087                                  item->nowildcard_len)) {
1088                         strbuf_setlen(base, base_offset + baselen);
1089                         goto interesting;
1090                 }
1091
1092                 /*
1093                  * When matching against submodules with
1094                  * wildcard characters, ensure that the entry
1095                  * at least matches up to the first wild
1096                  * character.  More accurate matching can then
1097                  * be performed in the submodule itself.
1098                  */
1099                 if (ps->recurse_submodules && S_ISGITLINK(entry->mode) &&
1100                     !ps_strncmp(item, match, base->buf + base_offset,
1101                                 item->nowildcard_len)) {
1102                         strbuf_setlen(base, base_offset + baselen);
1103                         goto interesting;
1104                 }
1105
1106                 strbuf_setlen(base, base_offset + baselen);
1107
1108                 /*
1109                  * Match all directories. We'll try to match files
1110                  * later on.
1111                  * max_depth is ignored but we may consider support it
1112                  * in future, see
1113                  * https://public-inbox.org/git/7vmxo5l2g4.fsf@alter.siamese.dyndns.org/
1114                  */
1115                 if (ps->recursive && S_ISDIR(entry->mode))
1116                         return entry_interesting;
1117                 continue;
1118 interesting:
1119                 if (item->attr_match_nr) {
1120                         int ret;
1121
1122                         /*
1123                          * Must not return all_entries_not_interesting
1124                          * prematurely. We do not know if all entries do not
1125                          * match some attributes with current attr API.
1126                          */
1127                         never_interesting = entry_not_interesting;
1128
1129                         /*
1130                          * Consider all directories interesting (because some
1131                          * of those files inside may match some attributes
1132                          * even though the parent dir does not)
1133                          *
1134                          * FIXME: attributes _can_ match directories and we
1135                          * can probably return all_entries_interesting or
1136                          * all_entries_not_interesting here if matched.
1137                          */
1138                         if (S_ISDIR(entry->mode))
1139                                 return entry_interesting;
1140
1141                         strbuf_add(base, entry->path, pathlen);
1142                         ret = match_pathspec_attrs(istate, base->buf + base_offset,
1143                                                    base->len - base_offset, item);
1144                         strbuf_setlen(base, base_offset + baselen);
1145                         if (!ret)
1146                                 continue;
1147                 }
1148                 return entry_interesting;
1149         }
1150         return never_interesting; /* No matches */
1151 }
1152
1153 /*
1154  * Is a tree entry interesting given the pathspec we have?
1155  *
1156  * Pre-condition: either baselen == base_offset (i.e. empty path)
1157  * or base[baselen-1] == '/' (i.e. with trailing slash).
1158  */
1159 enum interesting tree_entry_interesting(struct index_state *istate,
1160                                         const struct name_entry *entry,
1161                                         struct strbuf *base, int base_offset,
1162                                         const struct pathspec *ps)
1163 {
1164         enum interesting positive, negative;
1165         positive = do_match(istate, entry, base, base_offset, ps, 0);
1166
1167         /*
1168          * case | entry | positive | negative | result
1169          * -----+-------+----------+----------+-------
1170          *   1  |  file |   -1     |  -1..2   |  -1
1171          *   2  |  file |    0     |  -1..2   |   0
1172          *   3  |  file |    1     |   -1     |   1
1173          *   4  |  file |    1     |    0     |   1
1174          *   5  |  file |    1     |    1     |   0
1175          *   6  |  file |    1     |    2     |   0
1176          *   7  |  file |    2     |   -1     |   2
1177          *   8  |  file |    2     |    0     |   1
1178          *   9  |  file |    2     |    1     |   0
1179          *  10  |  file |    2     |    2     |  -1
1180          * -----+-------+----------+----------+-------
1181          *  11  |  dir  |   -1     |  -1..2   |  -1
1182          *  12  |  dir  |    0     |  -1..2   |   0
1183          *  13  |  dir  |    1     |   -1     |   1
1184          *  14  |  dir  |    1     |    0     |   1
1185          *  15  |  dir  |    1     |    1     |   1 (*)
1186          *  16  |  dir  |    1     |    2     |   0
1187          *  17  |  dir  |    2     |   -1     |   2
1188          *  18  |  dir  |    2     |    0     |   1
1189          *  19  |  dir  |    2     |    1     |   1 (*)
1190          *  20  |  dir  |    2     |    2     |  -1
1191          *
1192          * (*) An exclude pattern interested in a directory does not
1193          * necessarily mean it will exclude all of the directory. In
1194          * wildcard case, it can't decide until looking at individual
1195          * files inside. So don't write such directories off yet.
1196          */
1197
1198         if (!(ps->magic & PATHSPEC_EXCLUDE) ||
1199             positive <= entry_not_interesting) /* #1, #2, #11, #12 */
1200                 return positive;
1201
1202         negative = do_match(istate, entry, base, base_offset, ps, 1);
1203
1204         /* #8, #18 */
1205         if (positive == all_entries_interesting &&
1206             negative == entry_not_interesting)
1207                 return entry_interesting;
1208
1209         /* #3, #4, #7, #13, #14, #17 */
1210         if (negative <= entry_not_interesting)
1211                 return positive;
1212
1213         /* #15, #19 */
1214         if (S_ISDIR(entry->mode) &&
1215             positive >= entry_interesting &&
1216             negative == entry_interesting)
1217                 return entry_interesting;
1218
1219         if ((positive == entry_interesting &&
1220              negative >= entry_interesting) || /* #5, #6, #16 */
1221             (positive == all_entries_interesting &&
1222              negative == entry_interesting)) /* #9 */
1223                 return entry_not_interesting;
1224
1225         return all_entries_not_interesting; /* #10, #20 */
1226 }