git.oblomov.eu Git - git/blob - revision.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "refs.h"
   8 #include "revision.h"
   9 #include <regex.h>
  10 #include "grep.h"
  11
  12 static char *path_name(struct name_path *path, const char *name)
  13 {
  14         struct name_path *p;
  15         char *n, *m;
  16         int nlen = strlen(name);
  17         int len = nlen + 1;
  18
  19         for (p = path; p; p = p->up) {
  20                 if (p->elem_len)
  21                         len += p->elem_len + 1;
  22         }
  23         n = xmalloc(len);
  24         m = n + len - (nlen + 1);
  25         strcpy(m, name);
  26         for (p = path; p; p = p->up) {
  27                 if (p->elem_len) {
  28                         m -= p->elem_len + 1;
  29                         memcpy(m, p->elem, p->elem_len);
  30                         m[p->elem_len] = '/';
  31                 }
  32         }
  33         return n;
  34 }
  35
  36 void add_object(struct object *obj,
  37                 struct object_array *p,
  38                 struct name_path *path,
  39                 const char *name)
  40 {
  41         add_object_array(obj, path_name(path, name), p);
  42 }
  43
  44 static void mark_blob_uninteresting(struct blob *blob)
  45 {
  46         if (blob->object.flags & UNINTERESTING)
  47                 return;
  48         blob->object.flags |= UNINTERESTING;
  49 }
  50
  51 void mark_tree_uninteresting(struct tree *tree)
  52 {
  53         struct tree_desc desc;
  54         struct name_entry entry;
  55         struct object *obj = &tree->object;
  56
  57         if (obj->flags & UNINTERESTING)
  58                 return;
  59         obj->flags |= UNINTERESTING;
  60         if (!has_sha1_file(obj->sha1))
  61                 return;
  62         if (parse_tree(tree) < 0)
  63                 die("bad tree %s", sha1_to_hex(obj->sha1));
  64
  65         desc.buf = tree->buffer;
  66         desc.size = tree->size;
  67         while (tree_entry(&desc, &entry)) {
  68                 if (S_ISDIR(entry.mode))
  69                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  70                 else
  71                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  72         }
  73
  74         /*
  75          * We don't care about the tree any more
  76          * after it has been marked uninteresting.
  77          */
  78         free(tree->buffer);
  79         tree->buffer = NULL;
  80 }
  81
  82 void mark_parents_uninteresting(struct commit *commit)
  83 {
  84         struct commit_list *parents = commit->parents;
  85
  86         while (parents) {
  87                 struct commit *commit = parents->item;
  88                 if (!(commit->object.flags & UNINTERESTING)) {
  89                         commit->object.flags |= UNINTERESTING;
  90
  91                         /*
  92                          * Normally we haven't parsed the parent
  93                          * yet, so we won't have a parent of a parent
  94                          * here. However, it may turn out that we've
  95                          * reached this commit some other way (where it
  96                          * wasn't uninteresting), in which case we need
  97                          * to mark its parents recursively too..
  98                          */
  99                         if (commit->parents)
 100                                 mark_parents_uninteresting(commit);
 101                 }
 102
 103                 /*
 104                  * A missing commit is ok iff its parent is marked
 105                  * uninteresting.
 106                  *
 107                  * We just mark such a thing parsed, so that when
 108                  * it is popped next time around, we won't be trying
 109                  * to parse it and get an error.
 110                  */
 111                 if (!has_sha1_file(commit->object.sha1))
 112                         commit->object.parsed = 1;
 113                 parents = parents->next;
 114         }
 115 }
 116
 117 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 118 {
 119         add_object_array(obj, name, &revs->pending);
 120 }
 121
 122 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 123 {
 124         struct object *object;
 125
 126         object = parse_object(sha1);
 127         if (!object)
 128                 die("bad object %s", name);
 129         object->flags |= flags;
 130         return object;
 131 }
 132
 133 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 134 {
 135         unsigned long flags = object->flags;
 136
 137         /*
 138          * Tag object? Look what it points to..
 139          */
 140         while (object->type == OBJ_TAG) {
 141                 struct tag *tag = (struct tag *) object;
 142                 if (revs->tag_objects && !(flags & UNINTERESTING))
 143                         add_pending_object(revs, object, tag->tag);
 144                 object = parse_object(tag->tagged->sha1);
 145                 if (!object)
 146                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 147         }
 148
 149         /*
 150          * Commit object? Just return it, we'll do all the complex
 151          * reachability crud.
 152          */
 153         if (object->type == OBJ_COMMIT) {
 154                 struct commit *commit = (struct commit *)object;
 155                 if (parse_commit(commit) < 0)
 156                         die("unable to parse commit %s", name);
 157                 if (flags & UNINTERESTING) {
 158                         commit->object.flags |= UNINTERESTING;
 159                         mark_parents_uninteresting(commit);
 160                         revs->limited = 1;
 161                 }
 162                 return commit;
 163         }
 164
 165         /*
 166          * Tree object? Either mark it uniniteresting, or add it
 167          * to the list of objects to look at later..
 168          */
 169         if (object->type == OBJ_TREE) {
 170                 struct tree *tree = (struct tree *)object;
 171                 if (!revs->tree_objects)
 172                         return NULL;
 173                 if (flags & UNINTERESTING) {
 174                         mark_tree_uninteresting(tree);
 175                         return NULL;
 176                 }
 177                 add_pending_object(revs, object, "");
 178                 return NULL;
 179         }
 180
 181         /*
 182          * Blob object? You know the drill by now..
 183          */
 184         if (object->type == OBJ_BLOB) {
 185                 struct blob *blob = (struct blob *)object;
 186                 if (!revs->blob_objects)
 187                         return NULL;
 188                 if (flags & UNINTERESTING) {
 189                         mark_blob_uninteresting(blob);
 190                         return NULL;
 191                 }
 192                 add_pending_object(revs, object, "");
 193                 return NULL;
 194         }
 195         die("%s is unknown object", name);
 196 }
 197
 198 static int everybody_uninteresting(struct commit_list *orig)
 199 {
 200         struct commit_list *list = orig;
 201         while (list) {
 202                 struct commit *commit = list->item;
 203                 list = list->next;
 204                 if (commit->object.flags & UNINTERESTING)
 205                         continue;
 206                 return 0;
 207         }
 208         return 1;
 209 }
 210
 211 static int tree_difference = REV_TREE_SAME;
 212
 213 static void file_add_remove(struct diff_options *options,
 214                     int addremove, unsigned mode,
 215                     const unsigned char *sha1,
 216                     const char *base, const char *path)
 217 {
 218         int diff = REV_TREE_DIFFERENT;
 219
 220         /*
 221          * Is it an add of a new file? It means that the old tree
 222          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 223          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 224          * (and if it already was "REV_TREE_NEW", we'll keep it
 225          * "REV_TREE_NEW" of course).
 226          */
 227         if (addremove == '+') {
 228                 diff = tree_difference;
 229                 if (diff != REV_TREE_SAME)
 230                         return;
 231                 diff = REV_TREE_NEW;
 232         }
 233         tree_difference = diff;
 234 }
 235
 236 static void file_change(struct diff_options *options,
 237                  unsigned old_mode, unsigned new_mode,
 238                  const unsigned char *old_sha1,
 239                  const unsigned char *new_sha1,
 240                  const char *base, const char *path)
 241 {
 242         tree_difference = REV_TREE_DIFFERENT;
 243 }
 244
 245 int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 246 {
 247         if (!t1)
 248                 return REV_TREE_NEW;
 249         if (!t2)
 250                 return REV_TREE_DIFFERENT;
 251         tree_difference = REV_TREE_SAME;
 252         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 253                            &revs->pruning) < 0)
 254                 return REV_TREE_DIFFERENT;
 255         return tree_difference;
 256 }
 257
 258 int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 259 {
 260         int retval;
 261         void *tree;
 262         struct tree_desc empty, real;
 263
 264         if (!t1)
 265                 return 0;
 266
 267         tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
 268         if (!tree)
 269                 return 0;
 270         real.buf = tree;
 271
 272         empty.buf = "";
 273         empty.size = 0;
 274
 275         tree_difference = 0;
 276         retval = diff_tree(&empty, &real, "", &revs->pruning);
 277         free(tree);
 278
 279         return retval >= 0 && !tree_difference;
 280 }
 281
 282 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 283 {
 284         struct commit_list **pp, *parent;
 285         int tree_changed = 0, tree_same = 0;
 286
 287         if (!commit->tree)
 288                 return;
 289
 290         if (!commit->parents) {
 291                 if (!rev_same_tree_as_empty(revs, commit->tree))
 292                         commit->object.flags |= TREECHANGE;
 293                 return;
 294         }
 295
 296         pp = &commit->parents;
 297         while ((parent = *pp) != NULL) {
 298                 struct commit *p = parent->item;
 299
 300                 parse_commit(p);
 301                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 302                 case REV_TREE_SAME:
 303                         tree_same = 1;
 304                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 305                                 /* Even if a merge with an uninteresting
 306                                  * side branch brought the entire change
 307                                  * we are interested in, we do not want
 308                                  * to lose the other branches of this
 309                                  * merge, so we just keep going.
 310                                  */
 311                                 pp = &parent->next;
 312                                 continue;
 313                         }
 314                         parent->next = NULL;
 315                         commit->parents = parent;
 316                         return;
 317
 318                 case REV_TREE_NEW:
 319                         if (revs->remove_empty_trees &&
 320                             rev_same_tree_as_empty(revs, p->tree)) {
 321                                 /* We are adding all the specified
 322                                  * paths from this parent, so the
 323                                  * history beyond this parent is not
 324                                  * interesting.  Remove its parents
 325                                  * (they are grandparents for us).
 326                                  * IOW, we pretend this parent is a
 327                                  * "root" commit.
 328                                  */
 329                                 parse_commit(p);
 330                                 p->parents = NULL;
 331                         }
 332                 /* fallthrough */
 333                 case REV_TREE_DIFFERENT:
 334                         tree_changed = 1;
 335                         pp = &parent->next;
 336                         continue;
 337                 }
 338                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 339         }
 340         if (tree_changed && !tree_same)
 341                 commit->object.flags |= TREECHANGE;
 342 }
 343
 344 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 345 {
 346         struct commit_list *parent = commit->parents;
 347
 348         if (commit->object.flags & ADDED)
 349                 return;
 350         commit->object.flags |= ADDED;
 351
 352         /*
 353          * If the commit is uninteresting, don't try to
 354          * prune parents - we want the maximal uninteresting
 355          * set.
 356          *
 357          * Normally we haven't parsed the parent
 358          * yet, so we won't have a parent of a parent
 359          * here. However, it may turn out that we've
 360          * reached this commit some other way (where it
 361          * wasn't uninteresting), in which case we need
 362          * to mark its parents recursively too..
 363          */
 364         if (commit->object.flags & UNINTERESTING) {
 365                 while (parent) {
 366                         struct commit *p = parent->item;
 367                         parent = parent->next;
 368                         parse_commit(p);
 369                         p->object.flags |= UNINTERESTING;
 370                         if (p->parents)
 371                                 mark_parents_uninteresting(p);
 372                         if (p->object.flags & SEEN)
 373                                 continue;
 374                         p->object.flags |= SEEN;
 375                         insert_by_date(p, list);
 376                 }
 377                 return;
 378         }
 379
 380         /*
 381          * Ok, the commit wasn't uninteresting. Try to
 382          * simplify the commit history and find the parent
 383          * that has no differences in the path set if one exists.
 384          */
 385         if (revs->prune_fn)
 386                 revs->prune_fn(revs, commit);
 387
 388         if (revs->no_walk)
 389                 return;
 390
 391         parent = commit->parents;
 392         while (parent) {
 393                 struct commit *p = parent->item;
 394
 395                 parent = parent->next;
 396
 397                 parse_commit(p);
 398                 if (p->object.flags & SEEN)
 399                         continue;
 400                 p->object.flags |= SEEN;
 401                 insert_by_date(p, list);
 402         }
 403 }
 404
 405 static void limit_list(struct rev_info *revs)
 406 {
 407         struct commit_list *list = revs->commits;
 408         struct commit_list *newlist = NULL;
 409         struct commit_list **p = &newlist;
 410
 411         while (list) {
 412                 struct commit_list *entry = list;
 413                 struct commit *commit = list->item;
 414                 struct object *obj = &commit->object;
 415
 416                 list = list->next;
 417                 free(entry);
 418
 419                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 420                         obj->flags |= UNINTERESTING;
 421                 add_parents_to_list(revs, commit, &list);
 422                 if (obj->flags & UNINTERESTING) {
 423                         mark_parents_uninteresting(commit);
 424                         if (everybody_uninteresting(list))
 425                                 break;
 426                         continue;
 427                 }
 428                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 429                         continue;
 430                 p = &commit_list_insert(commit, p)->next;
 431         }
 432         if (revs->boundary) {
 433                 /* mark the ones that are on the result list first */
 434                 for (list = newlist; list; list = list->next) {
 435                         struct commit *commit = list->item;
 436                         commit->object.flags |= TMP_MARK;
 437                 }
 438                 for (list = newlist; list; list = list->next) {
 439                         struct commit *commit = list->item;
 440                         struct object *obj = &commit->object;
 441                         struct commit_list *parent;
 442                         if (obj->flags & UNINTERESTING)
 443                                 continue;
 444                         for (parent = commit->parents;
 445                              parent;
 446                              parent = parent->next) {
 447                                 struct commit *pcommit = parent->item;
 448                                 if (!(pcommit->object.flags & UNINTERESTING))
 449                                         continue;
 450                                 pcommit->object.flags |= BOUNDARY;
 451                                 if (pcommit->object.flags & TMP_MARK)
 452                                         continue;
 453                                 pcommit->object.flags |= TMP_MARK;
 454                                 p = &commit_list_insert(pcommit, p)->next;
 455                         }
 456                 }
 457                 for (list = newlist; list; list = list->next) {
 458                         struct commit *commit = list->item;
 459                         commit->object.flags &= ~TMP_MARK;
 460                 }
 461         }
 462         revs->commits = newlist;
 463 }
 464
 465 static int all_flags;
 466 static struct rev_info *all_revs;
 467
 468 static int handle_one_ref(const char *path, const unsigned char *sha1)
 469 {
 470         struct object *object = get_reference(all_revs, path, sha1, all_flags);
 471         add_pending_object(all_revs, object, "");
 472         return 0;
 473 }
 474
 475 static void handle_all(struct rev_info *revs, unsigned flags)
 476 {
 477         all_revs = revs;
 478         all_flags = flags;
 479         for_each_ref(handle_one_ref);
 480 }
 481
 482 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 483 {
 484         unsigned char sha1[20];
 485         struct object *it;
 486         struct commit *commit;
 487         struct commit_list *parents;
 488
 489         if (*arg == '^') {
 490                 flags ^= UNINTERESTING;
 491                 arg++;
 492         }
 493         if (get_sha1(arg, sha1))
 494                 return 0;
 495         while (1) {
 496                 it = get_reference(revs, arg, sha1, 0);
 497                 if (it->type != OBJ_TAG)
 498                         break;
 499                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 500         }
 501         if (it->type != OBJ_COMMIT)
 502                 return 0;
 503         commit = (struct commit *)it;
 504         for (parents = commit->parents; parents; parents = parents->next) {
 505                 it = &parents->item->object;
 506                 it->flags |= flags;
 507                 add_pending_object(revs, it, arg);
 508         }
 509         return 1;
 510 }
 511
 512 void init_revisions(struct rev_info *revs, const char *prefix)
 513 {
 514         memset(revs, 0, sizeof(*revs));
 515
 516         revs->abbrev = DEFAULT_ABBREV;
 517         revs->ignore_merges = 1;
 518         revs->simplify_history = 1;
 519         revs->pruning.recursive = 1;
 520         revs->pruning.add_remove = file_add_remove;
 521         revs->pruning.change = file_change;
 522         revs->lifo = 1;
 523         revs->dense = 1;
 524         revs->prefix = prefix;
 525         revs->max_age = -1;
 526         revs->min_age = -1;
 527         revs->max_count = -1;
 528
 529         revs->prune_fn = NULL;
 530         revs->prune_data = NULL;
 531
 532         revs->topo_setter = topo_sort_default_setter;
 533         revs->topo_getter = topo_sort_default_getter;
 534
 535         revs->commit_format = CMIT_FMT_DEFAULT;
 536
 537         diff_setup(&revs->diffopt);
 538 }
 539
 540 static void add_pending_commit_list(struct rev_info *revs,
 541                                     struct commit_list *commit_list,
 542                                     unsigned int flags)
 543 {
 544         while (commit_list) {
 545                 struct object *object = &commit_list->item->object;
 546                 object->flags |= flags;
 547                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 548                 commit_list = commit_list->next;
 549         }
 550 }
 551
 552 static void prepare_show_merge(struct rev_info *revs)
 553 {
 554         struct commit_list *bases;
 555         struct commit *head, *other;
 556         unsigned char sha1[20];
 557         const char **prune = NULL;
 558         int i, prune_num = 1; /* counting terminating NULL */
 559
 560         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 561                 die("--merge without HEAD?");
 562         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 563                 die("--merge without MERGE_HEAD?");
 564         add_pending_object(revs, &head->object, "HEAD");
 565         add_pending_object(revs, &other->object, "MERGE_HEAD");
 566         bases = get_merge_bases(head, other, 1);
 567         while (bases) {
 568                 struct commit *it = bases->item;
 569                 struct commit_list *n = bases->next;
 570                 free(bases);
 571                 bases = n;
 572                 it->object.flags |= UNINTERESTING;
 573                 add_pending_object(revs, &it->object, "(merge-base)");
 574         }
 575
 576         if (!active_nr)
 577                 read_cache();
 578         for (i = 0; i < active_nr; i++) {
 579                 struct cache_entry *ce = active_cache[i];
 580                 if (!ce_stage(ce))
 581                         continue;
 582                 if (ce_path_match(ce, revs->prune_data)) {
 583                         prune_num++;
 584                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 585                         prune[prune_num-2] = ce->name;
 586                         prune[prune_num-1] = NULL;
 587                 }
 588                 while ((i+1 < active_nr) &&
 589                        ce_same_name(ce, active_cache[i+1]))
 590                         i++;
 591         }
 592         revs->prune_data = prune;
 593 }
 594
 595 int handle_revision_arg(const char *arg, struct rev_info *revs,
 596                         int flags,
 597                         int cant_be_filename)
 598 {
 599         char *dotdot;
 600         struct object *object;
 601         unsigned char sha1[20];
 602         int local_flags;
 603
 604         dotdot = strstr(arg, "..");
 605         if (dotdot) {
 606                 unsigned char from_sha1[20];
 607                 const char *next = dotdot + 2;
 608                 const char *this = arg;
 609                 int symmetric = *next == '.';
 610                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 611
 612                 *dotdot = 0;
 613                 next += symmetric;
 614
 615                 if (!*next)
 616                         next = "HEAD";
 617                 if (dotdot == arg)
 618                         this = "HEAD";
 619                 if (!get_sha1(this, from_sha1) &&
 620                     !get_sha1(next, sha1)) {
 621                         struct commit *a, *b;
 622                         struct commit_list *exclude;
 623
 624                         a = lookup_commit_reference(from_sha1);
 625                         b = lookup_commit_reference(sha1);
 626                         if (!a || !b) {
 627                                 die(symmetric ?
 628                                     "Invalid symmetric difference expression %s...%s" :
 629                                     "Invalid revision range %s..%s",
 630                                     arg, next);
 631                         }
 632
 633                         if (!cant_be_filename) {
 634                                 *dotdot = '.';
 635                                 verify_non_filename(revs->prefix, arg);
 636                         }
 637
 638                         if (symmetric) {
 639                                 exclude = get_merge_bases(a, b, 1);
 640                                 add_pending_commit_list(revs, exclude,
 641                                                         flags_exclude);
 642                                 free_commit_list(exclude);
 643                                 a->object.flags |= flags;
 644                         } else
 645                                 a->object.flags |= flags_exclude;
 646                         b->object.flags |= flags;
 647                         add_pending_object(revs, &a->object, this);
 648                         add_pending_object(revs, &b->object, next);
 649                         return 0;
 650                 }
 651                 *dotdot = '.';
 652         }
 653         dotdot = strstr(arg, "^@");
 654         if (dotdot && !dotdot[2]) {
 655                 *dotdot = 0;
 656                 if (add_parents_only(revs, arg, flags))
 657                         return 0;
 658                 *dotdot = '^';
 659         }
 660         local_flags = 0;
 661         if (*arg == '^') {
 662                 local_flags = UNINTERESTING;
 663                 arg++;
 664         }
 665         if (get_sha1(arg, sha1))
 666                 return -1;
 667         if (!cant_be_filename)
 668                 verify_non_filename(revs->prefix, arg);
 669         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 670         add_pending_object(revs, object, arg);
 671         return 0;
 672 }
 673
 674 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 675 {
 676         if (!revs->grep_filter) {
 677                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 678                 opt->status_only = 1;
 679                 opt->pattern_tail = &(opt->pattern_list);
 680                 opt->regflags = REG_NEWLINE;
 681                 revs->grep_filter = opt;
 682         }
 683         append_grep_pattern(revs->grep_filter, ptn,
 684                             "command line", 0, what);
 685 }
 686
 687 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 688 {
 689         char *pat;
 690         const char *prefix;
 691         int patlen, fldlen;
 692
 693         fldlen = strlen(field);
 694         patlen = strlen(pattern);
 695         pat = xmalloc(patlen + fldlen + 10);
 696         prefix = ".*";
 697         if (*pattern == '^') {
 698                 prefix = "";
 699                 pattern++;
 700         }
 701         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 702         add_grep(revs, pat, GREP_PATTERN_HEAD);
 703 }
 704
 705 static void add_message_grep(struct rev_info *revs, const char *pattern)
 706 {
 707         add_grep(revs, pattern, GREP_PATTERN_BODY);
 708 }
 709
 710 static void add_ignore_packed(struct rev_info *revs, const char *name)
 711 {
 712         int num = ++revs->num_ignore_packed;
 713
 714         revs->ignore_packed = xrealloc(revs->ignore_packed,
 715                                        sizeof(const char **) * (num + 1));
 716         revs->ignore_packed[num-1] = name;
 717         revs->ignore_packed[num] = NULL;
 718 }
 719
 720 /*
 721  * Parse revision information, filling in the "rev_info" structure,
 722  * and removing the used arguments from the argument list.
 723  *
 724  * Returns the number of arguments left that weren't recognized
 725  * (which are also moved to the head of the argument list)
 726  */
 727 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 728 {
 729         int i, flags, seen_dashdash, show_merge;
 730         const char **unrecognized = argv + 1;
 731         int left = 1;
 732
 733         /* First, search for "--" */
 734         seen_dashdash = 0;
 735         for (i = 1; i < argc; i++) {
 736                 const char *arg = argv[i];
 737                 if (strcmp(arg, "--"))
 738                         continue;
 739                 argv[i] = NULL;
 740                 argc = i;
 741                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 742                 seen_dashdash = 1;
 743                 break;
 744         }
 745
 746         flags = show_merge = 0;
 747         for (i = 1; i < argc; i++) {
 748                 const char *arg = argv[i];
 749                 if (*arg == '-') {
 750                         int opts;
 751                         if (!strncmp(arg, "--max-count=", 12)) {
 752                                 revs->max_count = atoi(arg + 12);
 753                                 continue;
 754                         }
 755                         /* accept -<digit>, like traditional "head" */
 756                         if ((*arg == '-') && isdigit(arg[1])) {
 757                                 revs->max_count = atoi(arg + 1);
 758                                 continue;
 759                         }
 760                         if (!strcmp(arg, "-n")) {
 761                                 if (argc <= i + 1)
 762                                         die("-n requires an argument");
 763                                 revs->max_count = atoi(argv[++i]);
 764                                 continue;
 765                         }
 766                         if (!strncmp(arg,"-n",2)) {
 767                                 revs->max_count = atoi(arg + 2);
 768                                 continue;
 769                         }
 770                         if (!strncmp(arg, "--max-age=", 10)) {
 771                                 revs->max_age = atoi(arg + 10);
 772                                 continue;
 773                         }
 774                         if (!strncmp(arg, "--since=", 8)) {
 775                                 revs->max_age = approxidate(arg + 8);
 776                                 continue;
 777                         }
 778                         if (!strncmp(arg, "--after=", 8)) {
 779                                 revs->max_age = approxidate(arg + 8);
 780                                 continue;
 781                         }
 782                         if (!strncmp(arg, "--min-age=", 10)) {
 783                                 revs->min_age = atoi(arg + 10);
 784                                 continue;
 785                         }
 786                         if (!strncmp(arg, "--before=", 9)) {
 787                                 revs->min_age = approxidate(arg + 9);
 788                                 continue;
 789                         }
 790                         if (!strncmp(arg, "--until=", 8)) {
 791                                 revs->min_age = approxidate(arg + 8);
 792                                 continue;
 793                         }
 794                         if (!strcmp(arg, "--all")) {
 795                                 handle_all(revs, flags);
 796                                 continue;
 797                         }
 798                         if (!strcmp(arg, "--not")) {
 799                                 flags ^= UNINTERESTING;
 800                                 continue;
 801                         }
 802                         if (!strcmp(arg, "--default")) {
 803                                 if (++i >= argc)
 804                                         die("bad --default argument");
 805                                 def = argv[i];
 806                                 continue;
 807                         }
 808                         if (!strcmp(arg, "--merge")) {
 809                                 show_merge = 1;
 810                                 continue;
 811                         }
 812                         if (!strcmp(arg, "--topo-order")) {
 813                                 revs->topo_order = 1;
 814                                 continue;
 815                         }
 816                         if (!strcmp(arg, "--date-order")) {
 817                                 revs->lifo = 0;
 818                                 revs->topo_order = 1;
 819                                 continue;
 820                         }
 821                         if (!strcmp(arg, "--parents")) {
 822                                 revs->parents = 1;
 823                                 continue;
 824                         }
 825                         if (!strcmp(arg, "--dense")) {
 826                                 revs->dense = 1;
 827                                 continue;
 828                         }
 829                         if (!strcmp(arg, "--sparse")) {
 830                                 revs->dense = 0;
 831                                 continue;
 832                         }
 833                         if (!strcmp(arg, "--remove-empty")) {
 834                                 revs->remove_empty_trees = 1;
 835                                 continue;
 836                         }
 837                         if (!strcmp(arg, "--no-merges")) {
 838                                 revs->no_merges = 1;
 839                                 continue;
 840                         }
 841                         if (!strcmp(arg, "--boundary")) {
 842                                 revs->boundary = 1;
 843                                 continue;
 844                         }
 845                         if (!strcmp(arg, "--objects")) {
 846                                 revs->tag_objects = 1;
 847                                 revs->tree_objects = 1;
 848                                 revs->blob_objects = 1;
 849                                 continue;
 850                         }
 851                         if (!strcmp(arg, "--objects-edge")) {
 852                                 revs->tag_objects = 1;
 853                                 revs->tree_objects = 1;
 854                                 revs->blob_objects = 1;
 855                                 revs->edge_hint = 1;
 856                                 continue;
 857                         }
 858                         if (!strcmp(arg, "--unpacked")) {
 859                                 revs->unpacked = 1;
 860                                 free(revs->ignore_packed);
 861                                 revs->ignore_packed = NULL;
 862                                 revs->num_ignore_packed = 0;
 863                                 continue;
 864                         }
 865                         if (!strncmp(arg, "--unpacked=", 11)) {
 866                                 revs->unpacked = 1;
 867                                 add_ignore_packed(revs, arg+11);
 868                                 continue;
 869                         }
 870                         if (!strcmp(arg, "-r")) {
 871                                 revs->diff = 1;
 872                                 revs->diffopt.recursive = 1;
 873                                 continue;
 874                         }
 875                         if (!strcmp(arg, "-t")) {
 876                                 revs->diff = 1;
 877                                 revs->diffopt.recursive = 1;
 878                                 revs->diffopt.tree_in_recursive = 1;
 879                                 continue;
 880                         }
 881                         if (!strcmp(arg, "-m")) {
 882                                 revs->ignore_merges = 0;
 883                                 continue;
 884                         }
 885                         if (!strcmp(arg, "-c")) {
 886                                 revs->diff = 1;
 887                                 revs->dense_combined_merges = 0;
 888                                 revs->combine_merges = 1;
 889                                 continue;
 890                         }
 891                         if (!strcmp(arg, "--cc")) {
 892                                 revs->diff = 1;
 893                                 revs->dense_combined_merges = 1;
 894                                 revs->combine_merges = 1;
 895                                 continue;
 896                         }
 897                         if (!strcmp(arg, "-v")) {
 898                                 revs->verbose_header = 1;
 899                                 continue;
 900                         }
 901                         if (!strncmp(arg, "--pretty", 8)) {
 902                                 revs->verbose_header = 1;
 903                                 revs->commit_format = get_commit_format(arg+8);
 904                                 continue;
 905                         }
 906                         if (!strcmp(arg, "--root")) {
 907                                 revs->show_root_diff = 1;
 908                                 continue;
 909                         }
 910                         if (!strcmp(arg, "--no-commit-id")) {
 911                                 revs->no_commit_id = 1;
 912                                 continue;
 913                         }
 914                         if (!strcmp(arg, "--always")) {
 915                                 revs->always_show_header = 1;
 916                                 continue;
 917                         }
 918                         if (!strcmp(arg, "--no-abbrev")) {
 919                                 revs->abbrev = 0;
 920                                 continue;
 921                         }
 922                         if (!strcmp(arg, "--abbrev")) {
 923                                 revs->abbrev = DEFAULT_ABBREV;
 924                                 continue;
 925                         }
 926                         if (!strncmp(arg, "--abbrev=", 9)) {
 927                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
 928                                 if (revs->abbrev < MINIMUM_ABBREV)
 929                                         revs->abbrev = MINIMUM_ABBREV;
 930                                 else if (revs->abbrev > 40)
 931                                         revs->abbrev = 40;
 932                                 continue;
 933                         }
 934                         if (!strcmp(arg, "--abbrev-commit")) {
 935                                 revs->abbrev_commit = 1;
 936                                 continue;
 937                         }
 938                         if (!strcmp(arg, "--full-diff")) {
 939                                 revs->diff = 1;
 940                                 revs->full_diff = 1;
 941                                 continue;
 942                         }
 943                         if (!strcmp(arg, "--full-history")) {
 944                                 revs->simplify_history = 0;
 945                                 continue;
 946                         }
 947                         if (!strcmp(arg, "--relative-date")) {
 948                                 revs->relative_date = 1;
 949                                 continue;
 950                         }
 951
 952                         /*
 953                          * Grepping the commit log
 954                          */
 955                         if (!strncmp(arg, "--author=", 9)) {
 956                                 add_header_grep(revs, "author", arg+9);
 957                                 continue;
 958                         }
 959                         if (!strncmp(arg, "--committer=", 12)) {
 960                                 add_header_grep(revs, "committer", arg+12);
 961                                 continue;
 962                         }
 963                         if (!strncmp(arg, "--grep=", 7)) {
 964                                 add_message_grep(revs, arg+7);
 965                                 continue;
 966                         }
 967
 968                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
 969                         if (opts > 0) {
 970                                 revs->diff = 1;
 971                                 i += opts - 1;
 972                                 continue;
 973                         }
 974                         *unrecognized++ = arg;
 975                         left++;
 976                         continue;
 977                 }
 978
 979                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
 980                         int j;
 981                         if (seen_dashdash || *arg == '^')
 982                                 die("bad revision '%s'", arg);
 983
 984                         /* If we didn't have a "--":
 985                          * (1) all filenames must exist;
 986                          * (2) all rev-args must not be interpretable
 987                          *     as a valid filename.
 988                          * but the latter we have checked in the main loop.
 989                          */
 990                         for (j = i; j < argc; j++)
 991                                 verify_filename(revs->prefix, argv[j]);
 992
 993                         revs->prune_data = get_pathspec(revs->prefix,
 994                                                         argv + i);
 995                         break;
 996                 }
 997         }
 998
 999         if (show_merge)
1000                 prepare_show_merge(revs);
1001         if (def && !revs->pending.nr) {
1002                 unsigned char sha1[20];
1003                 struct object *object;
1004                 if (get_sha1(def, sha1))
1005                         die("bad default revision '%s'", def);
1006                 object = get_reference(revs, def, sha1, 0);
1007                 add_pending_object(revs, object, def);
1008         }
1009
1010         if (revs->topo_order)
1011                 revs->limited = 1;
1012
1013         if (revs->prune_data) {
1014                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1015                 revs->prune_fn = try_to_simplify_commit;
1016                 if (!revs->full_diff)
1017                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1018         }
1019         if (revs->combine_merges) {
1020                 revs->ignore_merges = 0;
1021                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1022                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1023         }
1024         revs->diffopt.abbrev = revs->abbrev;
1025         if (diff_setup_done(&revs->diffopt) < 0)
1026                 die("diff_setup_done failed");
1027
1028         if (revs->grep_filter)
1029                 compile_grep_patterns(revs->grep_filter);
1030
1031         return left;
1032 }
1033
1034 void prepare_revision_walk(struct rev_info *revs)
1035 {
1036         int nr = revs->pending.nr;
1037         struct object_array_entry *list = revs->pending.objects;
1038
1039         revs->pending.nr = 0;
1040         revs->pending.alloc = 0;
1041         revs->pending.objects = NULL;
1042         while (--nr >= 0) {
1043                 struct commit *commit = handle_commit(revs, list->item, list->name);
1044                 if (commit) {
1045                         if (!(commit->object.flags & SEEN)) {
1046                                 commit->object.flags |= SEEN;
1047                                 insert_by_date(commit, &revs->commits);
1048                         }
1049                 }
1050                 list++;
1051         }
1052
1053         if (revs->no_walk)
1054                 return;
1055         if (revs->limited)
1056                 limit_list(revs);
1057         if (revs->topo_order)
1058                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
1059                                              revs->topo_setter,
1060                                              revs->topo_getter);
1061 }
1062
1063 static int rewrite_one(struct rev_info *revs, struct commit **pp)
1064 {
1065         for (;;) {
1066                 struct commit *p = *pp;
1067                 if (!revs->limited)
1068                         add_parents_to_list(revs, p, &revs->commits);
1069                 if (p->parents && p->parents->next)
1070                         return 0;
1071                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
1072                         return 0;
1073                 if (!p->parents)
1074                         return -1;
1075                 *pp = p->parents->item;
1076         }
1077 }
1078
1079 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
1080 {
1081         struct commit_list **pp = &commit->parents;
1082         while (*pp) {
1083                 struct commit_list *parent = *pp;
1084                 if (rewrite_one(revs, &parent->item) < 0) {
1085                         *pp = parent->next;
1086                         continue;
1087                 }
1088                 pp = &parent->next;
1089         }
1090 }
1091
1092 static void mark_boundary_to_show(struct commit *commit)
1093 {
1094         struct commit_list *p = commit->parents;
1095         while (p) {
1096                 commit = p->item;
1097                 p = p->next;
1098                 if (commit->object.flags & BOUNDARY)
1099                         commit->object.flags |= BOUNDARY_SHOW;
1100         }
1101 }
1102
1103 static int commit_match(struct commit *commit, struct rev_info *opt)
1104 {
1105         if (!opt->grep_filter)
1106                 return 1;
1107         return grep_buffer(opt->grep_filter,
1108                            NULL, /* we say nothing, not even filename */
1109                            commit->buffer, strlen(commit->buffer));
1110 }
1111
1112 struct commit *get_revision(struct rev_info *revs)
1113 {
1114         struct commit_list *list = revs->commits;
1115
1116         if (!list)
1117                 return NULL;
1118
1119         /* Check the max_count ... */
1120         switch (revs->max_count) {
1121         case -1:
1122                 break;
1123         case 0:
1124                 return NULL;
1125         default:
1126                 revs->max_count--;
1127         }
1128
1129         do {
1130                 struct commit_list *entry = revs->commits;
1131                 struct commit *commit = entry->item;
1132
1133                 revs->commits = entry->next;
1134                 free(entry);
1135
1136                 /*
1137                  * If we haven't done the list limiting, we need to look at
1138                  * the parents here. We also need to do the date-based limiting
1139                  * that we'd otherwise have done in limit_list().
1140                  */
1141                 if (!revs->limited) {
1142                         if (revs->max_age != -1 &&
1143                             (commit->date < revs->max_age))
1144                                 continue;
1145                         add_parents_to_list(revs, commit, &revs->commits);
1146                 }
1147                 if (commit->object.flags & SHOWN)
1148                         continue;
1149
1150                 if (revs->unpacked && has_sha1_pack(commit->object.sha1,
1151                                                     revs->ignore_packed))
1152                     continue;
1153
1154                 /* We want to show boundary commits only when their
1155                  * children are shown.  When path-limiter is in effect,
1156                  * rewrite_parents() drops some commits from getting shown,
1157                  * and there is no point showing boundary parents that
1158                  * are not shown.  After rewrite_parents() rewrites the
1159                  * parents of a commit that is shown, we mark the boundary
1160                  * parents with BOUNDARY_SHOW.
1161                  */
1162                 if (commit->object.flags & BOUNDARY_SHOW) {
1163                         commit->object.flags |= SHOWN;
1164                         return commit;
1165                 }
1166                 if (commit->object.flags & UNINTERESTING)
1167                         continue;
1168                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1169                         continue;
1170                 if (revs->no_merges &&
1171                     commit->parents && commit->parents->next)
1172                         continue;
1173                 if (!commit_match(commit, revs))
1174                         continue;
1175                 if (revs->prune_fn && revs->dense) {
1176                         /* Commit without changes? */
1177                         if (!(commit->object.flags & TREECHANGE)) {
1178                                 /* drop merges unless we want parenthood */
1179                                 if (!revs->parents)
1180                                         continue;
1181                                 /* non-merge - always ignore it */
1182                                 if (!commit->parents || !commit->parents->next)
1183                                         continue;
1184                         }
1185                         if (revs->parents)
1186                                 rewrite_parents(revs, commit);
1187                 }
1188                 if (revs->boundary)
1189                         mark_boundary_to_show(commit);
1190                 commit->object.flags |= SHOWN;
1191                 return commit;
1192         } while (revs->commits);
1193         return NULL;
1194 }