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 "graph.h"
  10 #include "grep.h"
  11 #include "reflog-walk.h"
  12 #include "patch-ids.h"
  13 #include "decorate.h"
  14 #include "log-tree.h"
  15
  16 volatile show_early_output_fn_t show_early_output;
  17
  18 char *path_name(const struct name_path *path, const char *name)
  19 {
  20         const struct name_path *p;
  21         char *n, *m;
  22         int nlen = strlen(name);
  23         int len = nlen + 1;
  24
  25         for (p = path; p; p = p->up) {
  26                 if (p->elem_len)
  27                         len += p->elem_len + 1;
  28         }
  29         n = xmalloc(len);
  30         m = n + len - (nlen + 1);
  31         strcpy(m, name);
  32         for (p = path; p; p = p->up) {
  33                 if (p->elem_len) {
  34                         m -= p->elem_len + 1;
  35                         memcpy(m, p->elem, p->elem_len);
  36                         m[p->elem_len] = '/';
  37                 }
  38         }
  39         return n;
  40 }
  41
  42 void add_object(struct object *obj,
  43                 struct object_array *p,
  44                 struct name_path *path,
  45                 const char *name)
  46 {
  47         add_object_array(obj, path_name(path, name), p);
  48 }
  49
  50 static void mark_blob_uninteresting(struct blob *blob)
  51 {
  52         if (!blob)
  53                 return;
  54         if (blob->object.flags & UNINTERESTING)
  55                 return;
  56         blob->object.flags |= UNINTERESTING;
  57 }
  58
  59 void mark_tree_uninteresting(struct tree *tree)
  60 {
  61         struct tree_desc desc;
  62         struct name_entry entry;
  63         struct object *obj = &tree->object;
  64
  65         if (!tree)
  66                 return;
  67         if (obj->flags & UNINTERESTING)
  68                 return;
  69         obj->flags |= UNINTERESTING;
  70         if (!has_sha1_file(obj->sha1))
  71                 return;
  72         if (parse_tree(tree) < 0)
  73                 die("bad tree %s", sha1_to_hex(obj->sha1));
  74
  75         init_tree_desc(&desc, tree->buffer, tree->size);
  76         while (tree_entry(&desc, &entry)) {
  77                 switch (object_type(entry.mode)) {
  78                 case OBJ_TREE:
  79                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  80                         break;
  81                 case OBJ_BLOB:
  82                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  83                         break;
  84                 default:
  85                         /* Subproject commit - not in this repository */
  86                         break;
  87                 }
  88         }
  89
  90         /*
  91          * We don't care about the tree any more
  92          * after it has been marked uninteresting.
  93          */
  94         free(tree->buffer);
  95         tree->buffer = NULL;
  96 }
  97
  98 void mark_parents_uninteresting(struct commit *commit)
  99 {
 100         struct commit_list *parents = commit->parents;
 101
 102         while (parents) {
 103                 struct commit *commit = parents->item;
 104                 if (!(commit->object.flags & UNINTERESTING)) {
 105                         commit->object.flags |= UNINTERESTING;
 106
 107                         /*
 108                          * Normally we haven't parsed the parent
 109                          * yet, so we won't have a parent of a parent
 110                          * here. However, it may turn out that we've
 111                          * reached this commit some other way (where it
 112                          * wasn't uninteresting), in which case we need
 113                          * to mark its parents recursively too..
 114                          */
 115                         if (commit->parents)
 116                                 mark_parents_uninteresting(commit);
 117                 }
 118
 119                 /*
 120                  * A missing commit is ok iff its parent is marked
 121                  * uninteresting.
 122                  *
 123                  * We just mark such a thing parsed, so that when
 124                  * it is popped next time around, we won't be trying
 125                  * to parse it and get an error.
 126                  */
 127                 if (!has_sha1_file(commit->object.sha1))
 128                         commit->object.parsed = 1;
 129                 parents = parents->next;
 130         }
 131 }
 132
 133 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 134 {
 135         if (revs->no_walk && (obj->flags & UNINTERESTING))
 136                 revs->no_walk = 0;
 137         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 138                 struct strbuf buf = STRBUF_INIT;
 139                 int len = interpret_branch_name(name, &buf);
 140                 int st;
 141
 142                 if (0 < len && name[len] && buf.len)
 143                         strbuf_addstr(&buf, name + len);
 144                 st = add_reflog_for_walk(revs->reflog_info,
 145                                          (struct commit *)obj,
 146                                          buf.buf[0] ? buf.buf: name);
 147                 strbuf_release(&buf);
 148                 if (st)
 149                         return;
 150         }
 151         add_object_array_with_mode(obj, name, &revs->pending, mode);
 152 }
 153
 154 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 155 {
 156         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 157 }
 158
 159 void add_head_to_pending(struct rev_info *revs)
 160 {
 161         unsigned char sha1[20];
 162         struct object *obj;
 163         if (get_sha1("HEAD", sha1))
 164                 return;
 165         obj = parse_object(sha1);
 166         if (!obj)
 167                 return;
 168         add_pending_object(revs, obj, "HEAD");
 169 }
 170
 171 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 172 {
 173         struct object *object;
 174
 175         object = parse_object(sha1);
 176         if (!object)
 177                 die("bad object %s", name);
 178         object->flags |= flags;
 179         return object;
 180 }
 181
 182 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 183 {
 184         unsigned long flags = object->flags;
 185
 186         /*
 187          * Tag object? Look what it points to..
 188          */
 189         while (object->type == OBJ_TAG) {
 190                 struct tag *tag = (struct tag *) object;
 191                 if (revs->tag_objects && !(flags & UNINTERESTING))
 192                         add_pending_object(revs, object, tag->tag);
 193                 if (!tag->tagged)
 194                         die("bad tag");
 195                 object = parse_object(tag->tagged->sha1);
 196                 if (!object) {
 197                         if (flags & UNINTERESTING)
 198                                 return NULL;
 199                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 200                 }
 201         }
 202
 203         /*
 204          * Commit object? Just return it, we'll do all the complex
 205          * reachability crud.
 206          */
 207         if (object->type == OBJ_COMMIT) {
 208                 struct commit *commit = (struct commit *)object;
 209                 if (parse_commit(commit) < 0)
 210                         die("unable to parse commit %s", name);
 211                 if (flags & UNINTERESTING) {
 212                         commit->object.flags |= UNINTERESTING;
 213                         mark_parents_uninteresting(commit);
 214                         revs->limited = 1;
 215                 }
 216                 if (revs->show_source && !commit->util)
 217                         commit->util = (void *) name;
 218                 return commit;
 219         }
 220
 221         /*
 222          * Tree object? Either mark it uninteresting, or add it
 223          * to the list of objects to look at later..
 224          */
 225         if (object->type == OBJ_TREE) {
 226                 struct tree *tree = (struct tree *)object;
 227                 if (!revs->tree_objects)
 228                         return NULL;
 229                 if (flags & UNINTERESTING) {
 230                         mark_tree_uninteresting(tree);
 231                         return NULL;
 232                 }
 233                 add_pending_object(revs, object, "");
 234                 return NULL;
 235         }
 236
 237         /*
 238          * Blob object? You know the drill by now..
 239          */
 240         if (object->type == OBJ_BLOB) {
 241                 struct blob *blob = (struct blob *)object;
 242                 if (!revs->blob_objects)
 243                         return NULL;
 244                 if (flags & UNINTERESTING) {
 245                         mark_blob_uninteresting(blob);
 246                         return NULL;
 247                 }
 248                 add_pending_object(revs, object, "");
 249                 return NULL;
 250         }
 251         die("%s is unknown object", name);
 252 }
 253
 254 static int everybody_uninteresting(struct commit_list *orig)
 255 {
 256         struct commit_list *list = orig;
 257         while (list) {
 258                 struct commit *commit = list->item;
 259                 list = list->next;
 260                 if (commit->object.flags & UNINTERESTING)
 261                         continue;
 262                 return 0;
 263         }
 264         return 1;
 265 }
 266
 267 /*
 268  * The goal is to get REV_TREE_NEW as the result only if the
 269  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 270  * if the whole diff is removal of old data, and otherwise
 271  * REV_TREE_DIFFERENT (of course if the trees are the same we
 272  * want REV_TREE_SAME).
 273  * That means that once we get to REV_TREE_DIFFERENT, we do not
 274  * have to look any further.
 275  */
 276 static int tree_difference = REV_TREE_SAME;
 277
 278 static void file_add_remove(struct diff_options *options,
 279                     int addremove, unsigned mode,
 280                     const unsigned char *sha1,
 281                     const char *fullpath, unsigned dirty_submodule)
 282 {
 283         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 284
 285         tree_difference |= diff;
 286         if (tree_difference == REV_TREE_DIFFERENT)
 287                 DIFF_OPT_SET(options, HAS_CHANGES);
 288 }
 289
 290 static void file_change(struct diff_options *options,
 291                  unsigned old_mode, unsigned new_mode,
 292                  const unsigned char *old_sha1,
 293                  const unsigned char *new_sha1,
 294                  const char *fullpath,
 295                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 296 {
 297         tree_difference = REV_TREE_DIFFERENT;
 298         DIFF_OPT_SET(options, HAS_CHANGES);
 299 }
 300
 301 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 302 {
 303         struct tree *t1 = parent->tree;
 304         struct tree *t2 = commit->tree;
 305
 306         if (!t1)
 307                 return REV_TREE_NEW;
 308         if (!t2)
 309                 return REV_TREE_OLD;
 310
 311         if (revs->simplify_by_decoration) {
 312                 /*
 313                  * If we are simplifying by decoration, then the commit
 314                  * is worth showing if it has a tag pointing at it.
 315                  */
 316                 if (lookup_decoration(&name_decoration, &commit->object))
 317                         return REV_TREE_DIFFERENT;
 318                 /*
 319                  * A commit that is not pointed by a tag is uninteresting
 320                  * if we are not limited by path.  This means that you will
 321                  * see the usual "commits that touch the paths" plus any
 322                  * tagged commit by specifying both --simplify-by-decoration
 323                  * and pathspec.
 324                  */
 325                 if (!revs->prune_data)
 326                         return REV_TREE_SAME;
 327         }
 328
 329         tree_difference = REV_TREE_SAME;
 330         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 331         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 332                            &revs->pruning) < 0)
 333                 return REV_TREE_DIFFERENT;
 334         return tree_difference;
 335 }
 336
 337 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 338 {
 339         int retval;
 340         void *tree;
 341         unsigned long size;
 342         struct tree_desc empty, real;
 343         struct tree *t1 = commit->tree;
 344
 345         if (!t1)
 346                 return 0;
 347
 348         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 349         if (!tree)
 350                 return 0;
 351         init_tree_desc(&real, tree, size);
 352         init_tree_desc(&empty, "", 0);
 353
 354         tree_difference = REV_TREE_SAME;
 355         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 356         retval = diff_tree(&empty, &real, "", &revs->pruning);
 357         free(tree);
 358
 359         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 360 }
 361
 362 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 363 {
 364         struct commit_list **pp, *parent;
 365         int tree_changed = 0, tree_same = 0;
 366
 367         /*
 368          * If we don't do pruning, everything is interesting
 369          */
 370         if (!revs->prune)
 371                 return;
 372
 373         if (!commit->tree)
 374                 return;
 375
 376         if (!commit->parents) {
 377                 if (rev_same_tree_as_empty(revs, commit))
 378                         commit->object.flags |= TREESAME;
 379                 return;
 380         }
 381
 382         /*
 383          * Normal non-merge commit? If we don't want to make the
 384          * history dense, we consider it always to be a change..
 385          */
 386         if (!revs->dense && !commit->parents->next)
 387                 return;
 388
 389         pp = &commit->parents;
 390         while ((parent = *pp) != NULL) {
 391                 struct commit *p = parent->item;
 392
 393                 if (parse_commit(p) < 0)
 394                         die("cannot simplify commit %s (because of %s)",
 395                             sha1_to_hex(commit->object.sha1),
 396                             sha1_to_hex(p->object.sha1));
 397                 switch (rev_compare_tree(revs, p, commit)) {
 398                 case REV_TREE_SAME:
 399                         tree_same = 1;
 400                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 401                                 /* Even if a merge with an uninteresting
 402                                  * side branch brought the entire change
 403                                  * we are interested in, we do not want
 404                                  * to lose the other branches of this
 405                                  * merge, so we just keep going.
 406                                  */
 407                                 pp = &parent->next;
 408                                 continue;
 409                         }
 410                         parent->next = NULL;
 411                         commit->parents = parent;
 412                         commit->object.flags |= TREESAME;
 413                         return;
 414
 415                 case REV_TREE_NEW:
 416                         if (revs->remove_empty_trees &&
 417                             rev_same_tree_as_empty(revs, p)) {
 418                                 /* We are adding all the specified
 419                                  * paths from this parent, so the
 420                                  * history beyond this parent is not
 421                                  * interesting.  Remove its parents
 422                                  * (they are grandparents for us).
 423                                  * IOW, we pretend this parent is a
 424                                  * "root" commit.
 425                                  */
 426                                 if (parse_commit(p) < 0)
 427                                         die("cannot simplify commit %s (invalid %s)",
 428                                             sha1_to_hex(commit->object.sha1),
 429                                             sha1_to_hex(p->object.sha1));
 430                                 p->parents = NULL;
 431                         }
 432                 /* fallthrough */
 433                 case REV_TREE_OLD:
 434                 case REV_TREE_DIFFERENT:
 435                         tree_changed = 1;
 436                         pp = &parent->next;
 437                         continue;
 438                 }
 439                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 440         }
 441         if (tree_changed && !tree_same)
 442                 return;
 443         commit->object.flags |= TREESAME;
 444 }
 445
 446 static void insert_by_date_cached(struct commit *p, struct commit_list **head,
 447                     struct commit_list *cached_base, struct commit_list **cache)
 448 {
 449         struct commit_list *new_entry;
 450
 451         if (cached_base && p->date < cached_base->item->date)
 452                 new_entry = insert_by_date(p, &cached_base->next);
 453         else
 454                 new_entry = insert_by_date(p, head);
 455
 456         if (cache && (!*cache || p->date < (*cache)->item->date))
 457                 *cache = new_entry;
 458 }
 459
 460 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 461                     struct commit_list **list, struct commit_list **cache_ptr)
 462 {
 463         struct commit_list *parent = commit->parents;
 464         unsigned left_flag;
 465         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 466
 467         if (commit->object.flags & ADDED)
 468                 return 0;
 469         commit->object.flags |= ADDED;
 470
 471         /*
 472          * If the commit is uninteresting, don't try to
 473          * prune parents - we want the maximal uninteresting
 474          * set.
 475          *
 476          * Normally we haven't parsed the parent
 477          * yet, so we won't have a parent of a parent
 478          * here. However, it may turn out that we've
 479          * reached this commit some other way (where it
 480          * wasn't uninteresting), in which case we need
 481          * to mark its parents recursively too..
 482          */
 483         if (commit->object.flags & UNINTERESTING) {
 484                 while (parent) {
 485                         struct commit *p = parent->item;
 486                         parent = parent->next;
 487                         if (p)
 488                                 p->object.flags |= UNINTERESTING;
 489                         if (parse_commit(p) < 0)
 490                                 continue;
 491                         if (p->parents)
 492                                 mark_parents_uninteresting(p);
 493                         if (p->object.flags & SEEN)
 494                                 continue;
 495                         p->object.flags |= SEEN;
 496                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 497                 }
 498                 return 0;
 499         }
 500
 501         /*
 502          * Ok, the commit wasn't uninteresting. Try to
 503          * simplify the commit history and find the parent
 504          * that has no differences in the path set if one exists.
 505          */
 506         try_to_simplify_commit(revs, commit);
 507
 508         if (revs->no_walk)
 509                 return 0;
 510
 511         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 512
 513         for (parent = commit->parents; parent; parent = parent->next) {
 514                 struct commit *p = parent->item;
 515
 516                 if (parse_commit(p) < 0)
 517                         return -1;
 518                 if (revs->show_source && !p->util)
 519                         p->util = commit->util;
 520                 p->object.flags |= left_flag;
 521                 if (!(p->object.flags & SEEN)) {
 522                         p->object.flags |= SEEN;
 523                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 524                 }
 525                 if (revs->first_parent_only)
 526                         break;
 527         }
 528         return 0;
 529 }
 530
 531 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 532 {
 533         struct commit_list *p;
 534         int left_count = 0, right_count = 0;
 535         int left_first;
 536         struct patch_ids ids;
 537
 538         /* First count the commits on the left and on the right */
 539         for (p = list; p; p = p->next) {
 540                 struct commit *commit = p->item;
 541                 unsigned flags = commit->object.flags;
 542                 if (flags & BOUNDARY)
 543                         ;
 544                 else if (flags & SYMMETRIC_LEFT)
 545                         left_count++;
 546                 else
 547                         right_count++;
 548         }
 549
 550         if (!left_count || !right_count)
 551                 return;
 552
 553         left_first = left_count < right_count;
 554         init_patch_ids(&ids);
 555         if (revs->diffopt.nr_paths) {
 556                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 557                 ids.diffopts.paths = revs->diffopt.paths;
 558                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 559         }
 560
 561         /* Compute patch-ids for one side */
 562         for (p = list; p; p = p->next) {
 563                 struct commit *commit = p->item;
 564                 unsigned flags = commit->object.flags;
 565
 566                 if (flags & BOUNDARY)
 567                         continue;
 568                 /*
 569                  * If we have fewer left, left_first is set and we omit
 570                  * commits on the right branch in this loop.  If we have
 571                  * fewer right, we skip the left ones.
 572                  */
 573                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 574                         continue;
 575                 commit->util = add_commit_patch_id(commit, &ids);
 576         }
 577
 578         /* Check the other side */
 579         for (p = list; p; p = p->next) {
 580                 struct commit *commit = p->item;
 581                 struct patch_id *id;
 582                 unsigned flags = commit->object.flags;
 583
 584                 if (flags & BOUNDARY)
 585                         continue;
 586                 /*
 587                  * If we have fewer left, left_first is set and we omit
 588                  * commits on the left branch in this loop.
 589                  */
 590                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 591                         continue;
 592
 593                 /*
 594                  * Have we seen the same patch id?
 595                  */
 596                 id = has_commit_patch_id(commit, &ids);
 597                 if (!id)
 598                         continue;
 599                 id->seen = 1;
 600                 commit->object.flags |= SHOWN;
 601         }
 602
 603         /* Now check the original side for seen ones */
 604         for (p = list; p; p = p->next) {
 605                 struct commit *commit = p->item;
 606                 struct patch_id *ent;
 607
 608                 ent = commit->util;
 609                 if (!ent)
 610                         continue;
 611                 if (ent->seen)
 612                         commit->object.flags |= SHOWN;
 613                 commit->util = NULL;
 614         }
 615
 616         free_patch_ids(&ids);
 617 }
 618
 619 /* How many extra uninteresting commits we want to see.. */
 620 #define SLOP 5
 621
 622 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 623 {
 624         /*
 625          * No source list at all? We're definitely done..
 626          */
 627         if (!src)
 628                 return 0;
 629
 630         /*
 631          * Does the destination list contain entries with a date
 632          * before the source list? Definitely _not_ done.
 633          */
 634         if (date < src->item->date)
 635                 return SLOP;
 636
 637         /*
 638          * Does the source list still have interesting commits in
 639          * it? Definitely not done..
 640          */
 641         if (!everybody_uninteresting(src))
 642                 return SLOP;
 643
 644         /* Ok, we're closing in.. */
 645         return slop-1;
 646 }
 647
 648 static int limit_list(struct rev_info *revs)
 649 {
 650         int slop = SLOP;
 651         unsigned long date = ~0ul;
 652         struct commit_list *list = revs->commits;
 653         struct commit_list *newlist = NULL;
 654         struct commit_list **p = &newlist;
 655
 656         while (list) {
 657                 struct commit_list *entry = list;
 658                 struct commit *commit = list->item;
 659                 struct object *obj = &commit->object;
 660                 show_early_output_fn_t show;
 661
 662                 list = list->next;
 663                 free(entry);
 664
 665                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 666                         obj->flags |= UNINTERESTING;
 667                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 668                         return -1;
 669                 if (obj->flags & UNINTERESTING) {
 670                         mark_parents_uninteresting(commit);
 671                         if (revs->show_all)
 672                                 p = &commit_list_insert(commit, p)->next;
 673                         slop = still_interesting(list, date, slop);
 674                         if (slop)
 675                                 continue;
 676                         /* If showing all, add the whole pending list to the end */
 677                         if (revs->show_all)
 678                                 *p = list;
 679                         break;
 680                 }
 681                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 682                         continue;
 683                 date = commit->date;
 684                 p = &commit_list_insert(commit, p)->next;
 685
 686                 show = show_early_output;
 687                 if (!show)
 688                         continue;
 689
 690                 show(revs, newlist);
 691                 show_early_output = NULL;
 692         }
 693         if (revs->cherry_pick)
 694                 cherry_pick_list(newlist, revs);
 695
 696         revs->commits = newlist;
 697         return 0;
 698 }
 699
 700 struct all_refs_cb {
 701         int all_flags;
 702         int warned_bad_reflog;
 703         struct rev_info *all_revs;
 704         const char *name_for_errormsg;
 705 };
 706
 707 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 708 {
 709         struct all_refs_cb *cb = cb_data;
 710         struct object *object = get_reference(cb->all_revs, path, sha1,
 711                                               cb->all_flags);
 712         add_pending_object(cb->all_revs, object, path);
 713         return 0;
 714 }
 715
 716 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
 717         unsigned flags)
 718 {
 719         cb->all_revs = revs;
 720         cb->all_flags = flags;
 721 }
 722
 723 static void handle_refs(struct rev_info *revs, unsigned flags,
 724                 int (*for_each)(each_ref_fn, void *))
 725 {
 726         struct all_refs_cb cb;
 727         init_all_refs_cb(&cb, revs, flags);
 728         for_each(handle_one_ref, &cb);
 729 }
 730
 731 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 732 {
 733         struct all_refs_cb *cb = cb_data;
 734         if (!is_null_sha1(sha1)) {
 735                 struct object *o = parse_object(sha1);
 736                 if (o) {
 737                         o->flags |= cb->all_flags;
 738                         add_pending_object(cb->all_revs, o, "");
 739                 }
 740                 else if (!cb->warned_bad_reflog) {
 741                         warning("reflog of '%s' references pruned commits",
 742                                 cb->name_for_errormsg);
 743                         cb->warned_bad_reflog = 1;
 744                 }
 745         }
 746 }
 747
 748 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 749                 const char *email, unsigned long timestamp, int tz,
 750                 const char *message, void *cb_data)
 751 {
 752         handle_one_reflog_commit(osha1, cb_data);
 753         handle_one_reflog_commit(nsha1, cb_data);
 754         return 0;
 755 }
 756
 757 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 758 {
 759         struct all_refs_cb *cb = cb_data;
 760         cb->warned_bad_reflog = 0;
 761         cb->name_for_errormsg = path;
 762         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 763         return 0;
 764 }
 765
 766 static void handle_reflog(struct rev_info *revs, unsigned flags)
 767 {
 768         struct all_refs_cb cb;
 769         cb.all_revs = revs;
 770         cb.all_flags = flags;
 771         for_each_reflog(handle_one_reflog, &cb);
 772 }
 773
 774 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 775 {
 776         unsigned char sha1[20];
 777         struct object *it;
 778         struct commit *commit;
 779         struct commit_list *parents;
 780
 781         if (*arg == '^') {
 782                 flags ^= UNINTERESTING;
 783                 arg++;
 784         }
 785         if (get_sha1(arg, sha1))
 786                 return 0;
 787         while (1) {
 788                 it = get_reference(revs, arg, sha1, 0);
 789                 if (it->type != OBJ_TAG)
 790                         break;
 791                 if (!((struct tag*)it)->tagged)
 792                         return 0;
 793                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 794         }
 795         if (it->type != OBJ_COMMIT)
 796                 return 0;
 797         commit = (struct commit *)it;
 798         for (parents = commit->parents; parents; parents = parents->next) {
 799                 it = &parents->item->object;
 800                 it->flags |= flags;
 801                 add_pending_object(revs, it, arg);
 802         }
 803         return 1;
 804 }
 805
 806 void init_revisions(struct rev_info *revs, const char *prefix)
 807 {
 808         memset(revs, 0, sizeof(*revs));
 809
 810         revs->abbrev = DEFAULT_ABBREV;
 811         revs->ignore_merges = 1;
 812         revs->simplify_history = 1;
 813         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 814         DIFF_OPT_SET(&revs->pruning, QUICK);
 815         revs->pruning.add_remove = file_add_remove;
 816         revs->pruning.change = file_change;
 817         revs->lifo = 1;
 818         revs->dense = 1;
 819         revs->prefix = prefix;
 820         revs->max_age = -1;
 821         revs->min_age = -1;
 822         revs->skip_count = -1;
 823         revs->max_count = -1;
 824
 825         revs->commit_format = CMIT_FMT_DEFAULT;
 826
 827         revs->grep_filter.status_only = 1;
 828         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 829         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
 830         revs->grep_filter.regflags = REG_NEWLINE;
 831
 832         diff_setup(&revs->diffopt);
 833         if (prefix && !revs->diffopt.prefix) {
 834                 revs->diffopt.prefix = prefix;
 835                 revs->diffopt.prefix_length = strlen(prefix);
 836         }
 837 }
 838
 839 static void add_pending_commit_list(struct rev_info *revs,
 840                                     struct commit_list *commit_list,
 841                                     unsigned int flags)
 842 {
 843         while (commit_list) {
 844                 struct object *object = &commit_list->item->object;
 845                 object->flags |= flags;
 846                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 847                 commit_list = commit_list->next;
 848         }
 849 }
 850
 851 static void prepare_show_merge(struct rev_info *revs)
 852 {
 853         struct commit_list *bases;
 854         struct commit *head, *other;
 855         unsigned char sha1[20];
 856         const char **prune = NULL;
 857         int i, prune_num = 1; /* counting terminating NULL */
 858
 859         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 860                 die("--merge without HEAD?");
 861         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 862                 die("--merge without MERGE_HEAD?");
 863         add_pending_object(revs, &head->object, "HEAD");
 864         add_pending_object(revs, &other->object, "MERGE_HEAD");
 865         bases = get_merge_bases(head, other, 1);
 866         add_pending_commit_list(revs, bases, UNINTERESTING);
 867         free_commit_list(bases);
 868         head->object.flags |= SYMMETRIC_LEFT;
 869
 870         if (!active_nr)
 871                 read_cache();
 872         for (i = 0; i < active_nr; i++) {
 873                 struct cache_entry *ce = active_cache[i];
 874                 if (!ce_stage(ce))
 875                         continue;
 876                 if (ce_path_match(ce, revs->prune_data)) {
 877                         prune_num++;
 878                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 879                         prune[prune_num-2] = ce->name;
 880                         prune[prune_num-1] = NULL;
 881                 }
 882                 while ((i+1 < active_nr) &&
 883                        ce_same_name(ce, active_cache[i+1]))
 884                         i++;
 885         }
 886         revs->prune_data = prune;
 887         revs->limited = 1;
 888 }
 889
 890 int handle_revision_arg(const char *arg, struct rev_info *revs,
 891                         int flags,
 892                         int cant_be_filename)
 893 {
 894         unsigned mode;
 895         char *dotdot;
 896         struct object *object;
 897         unsigned char sha1[20];
 898         int local_flags;
 899
 900         dotdot = strstr(arg, "..");
 901         if (dotdot) {
 902                 unsigned char from_sha1[20];
 903                 const char *next = dotdot + 2;
 904                 const char *this = arg;
 905                 int symmetric = *next == '.';
 906                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 907
 908                 *dotdot = 0;
 909                 next += symmetric;
 910
 911                 if (!*next)
 912                         next = "HEAD";
 913                 if (dotdot == arg)
 914                         this = "HEAD";
 915                 if (!get_sha1(this, from_sha1) &&
 916                     !get_sha1(next, sha1)) {
 917                         struct commit *a, *b;
 918                         struct commit_list *exclude;
 919
 920                         a = lookup_commit_reference(from_sha1);
 921                         b = lookup_commit_reference(sha1);
 922                         if (!a || !b) {
 923                                 die(symmetric ?
 924                                     "Invalid symmetric difference expression %s...%s" :
 925                                     "Invalid revision range %s..%s",
 926                                     arg, next);
 927                         }
 928
 929                         if (!cant_be_filename) {
 930                                 *dotdot = '.';
 931                                 verify_non_filename(revs->prefix, arg);
 932                         }
 933
 934                         if (symmetric) {
 935                                 exclude = get_merge_bases(a, b, 1);
 936                                 add_pending_commit_list(revs, exclude,
 937                                                         flags_exclude);
 938                                 free_commit_list(exclude);
 939                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 940                         } else
 941                                 a->object.flags |= flags_exclude;
 942                         b->object.flags |= flags;
 943                         add_pending_object(revs, &a->object, this);
 944                         add_pending_object(revs, &b->object, next);
 945                         return 0;
 946                 }
 947                 *dotdot = '.';
 948         }
 949         dotdot = strstr(arg, "^@");
 950         if (dotdot && !dotdot[2]) {
 951                 *dotdot = 0;
 952                 if (add_parents_only(revs, arg, flags))
 953                         return 0;
 954                 *dotdot = '^';
 955         }
 956         dotdot = strstr(arg, "^!");
 957         if (dotdot && !dotdot[2]) {
 958                 *dotdot = 0;
 959                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 960                         *dotdot = '^';
 961         }
 962
 963         local_flags = 0;
 964         if (*arg == '^') {
 965                 local_flags = UNINTERESTING;
 966                 arg++;
 967         }
 968         if (get_sha1_with_mode(arg, sha1, &mode))
 969                 return -1;
 970         if (!cant_be_filename)
 971                 verify_non_filename(revs->prefix, arg);
 972         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 973         add_pending_object_with_mode(revs, object, arg, mode);
 974         return 0;
 975 }
 976
 977 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
 978 {
 979         const char **prune = *prune_data;
 980         int prune_nr;
 981         int prune_alloc;
 982
 983         /* count existing ones */
 984         if (!prune)
 985                 prune_nr = 0;
 986         else
 987                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
 988                         ;
 989         prune_alloc = prune_nr; /* not really, but we do not know */
 990
 991         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
 992                 int len = sb->len;
 993                 if (len && sb->buf[len - 1] == '\n')
 994                         sb->buf[--len] = '\0';
 995                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
 996                 prune[prune_nr++] = xstrdup(sb->buf);
 997         }
 998         if (prune) {
 999                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1000                 prune[prune_nr] = NULL;
1001         }
1002         *prune_data = prune;
1003 }
1004
1005 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1006 {
1007         struct strbuf sb;
1008         int seen_dashdash = 0;
1009
1010         strbuf_init(&sb, 1000);
1011         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1012                 int len = sb.len;
1013                 if (len && sb.buf[len - 1] == '\n')
1014                         sb.buf[--len] = '\0';
1015                 if (!len)
1016                         break;
1017                 if (sb.buf[0] == '-') {
1018                         if (len == 2 && sb.buf[1] == '-') {
1019                                 seen_dashdash = 1;
1020                                 break;
1021                         }
1022                         die("options not supported in --stdin mode");
1023                 }
1024                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1025                         die("bad revision '%s'", sb.buf);
1026         }
1027         if (seen_dashdash)
1028                 read_pathspec_from_stdin(revs, &sb, prune);
1029         strbuf_release(&sb);
1030 }
1031
1032 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1033 {
1034         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1035 }
1036
1037 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1038 {
1039         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1040 }
1041
1042 static void add_message_grep(struct rev_info *revs, const char *pattern)
1043 {
1044         add_grep(revs, pattern, GREP_PATTERN_BODY);
1045 }
1046
1047 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1048                                int *unkc, const char **unkv)
1049 {
1050         const char *arg = argv[0];
1051
1052         /* pseudo revision arguments */
1053         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1054             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1055             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1056             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1057             !strcmp(arg, "--bisect"))
1058         {
1059                 unkv[(*unkc)++] = arg;
1060                 return 1;
1061         }
1062
1063         if (!prefixcmp(arg, "--max-count=")) {
1064                 revs->max_count = atoi(arg + 12);
1065         } else if (!prefixcmp(arg, "--skip=")) {
1066                 revs->skip_count = atoi(arg + 7);
1067         } else if ((*arg == '-') && isdigit(arg[1])) {
1068         /* accept -<digit>, like traditional "head" */
1069                 revs->max_count = atoi(arg + 1);
1070         } else if (!strcmp(arg, "-n")) {
1071                 if (argc <= 1)
1072                         return error("-n requires an argument");
1073                 revs->max_count = atoi(argv[1]);
1074                 return 2;
1075         } else if (!prefixcmp(arg, "-n")) {
1076                 revs->max_count = atoi(arg + 2);
1077         } else if (!prefixcmp(arg, "--max-age=")) {
1078                 revs->max_age = atoi(arg + 10);
1079         } else if (!prefixcmp(arg, "--since=")) {
1080                 revs->max_age = approxidate(arg + 8);
1081         } else if (!prefixcmp(arg, "--after=")) {
1082                 revs->max_age = approxidate(arg + 8);
1083         } else if (!prefixcmp(arg, "--min-age=")) {
1084                 revs->min_age = atoi(arg + 10);
1085         } else if (!prefixcmp(arg, "--before=")) {
1086                 revs->min_age = approxidate(arg + 9);
1087         } else if (!prefixcmp(arg, "--until=")) {
1088                 revs->min_age = approxidate(arg + 8);
1089         } else if (!strcmp(arg, "--first-parent")) {
1090                 revs->first_parent_only = 1;
1091         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1092                 init_reflog_walk(&revs->reflog_info);
1093         } else if (!strcmp(arg, "--default")) {
1094                 if (argc <= 1)
1095                         return error("bad --default argument");
1096                 revs->def = argv[1];
1097                 return 2;
1098         } else if (!strcmp(arg, "--merge")) {
1099                 revs->show_merge = 1;
1100         } else if (!strcmp(arg, "--topo-order")) {
1101                 revs->lifo = 1;
1102                 revs->topo_order = 1;
1103         } else if (!strcmp(arg, "--simplify-merges")) {
1104                 revs->simplify_merges = 1;
1105                 revs->rewrite_parents = 1;
1106                 revs->simplify_history = 0;
1107                 revs->limited = 1;
1108         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1109                 revs->simplify_merges = 1;
1110                 revs->rewrite_parents = 1;
1111                 revs->simplify_history = 0;
1112                 revs->simplify_by_decoration = 1;
1113                 revs->limited = 1;
1114                 revs->prune = 1;
1115                 load_ref_decorations(DECORATE_SHORT_REFS);
1116         } else if (!strcmp(arg, "--date-order")) {
1117                 revs->lifo = 0;
1118                 revs->topo_order = 1;
1119         } else if (!prefixcmp(arg, "--early-output")) {
1120                 int count = 100;
1121                 switch (arg[14]) {
1122                 case '=':
1123                         count = atoi(arg+15);
1124                         /* Fallthrough */
1125                 case 0:
1126                         revs->topo_order = 1;
1127                        revs->early_output = count;
1128                 }
1129         } else if (!strcmp(arg, "--parents")) {
1130                 revs->rewrite_parents = 1;
1131                 revs->print_parents = 1;
1132         } else if (!strcmp(arg, "--dense")) {
1133                 revs->dense = 1;
1134         } else if (!strcmp(arg, "--sparse")) {
1135                 revs->dense = 0;
1136         } else if (!strcmp(arg, "--show-all")) {
1137                 revs->show_all = 1;
1138         } else if (!strcmp(arg, "--remove-empty")) {
1139                 revs->remove_empty_trees = 1;
1140         } else if (!strcmp(arg, "--merges")) {
1141                 revs->merges_only = 1;
1142         } else if (!strcmp(arg, "--no-merges")) {
1143                 revs->no_merges = 1;
1144         } else if (!strcmp(arg, "--boundary")) {
1145                 revs->boundary = 1;
1146         } else if (!strcmp(arg, "--left-right")) {
1147                 revs->left_right = 1;
1148         } else if (!strcmp(arg, "--cherry-pick")) {
1149                 revs->cherry_pick = 1;
1150                 revs->limited = 1;
1151         } else if (!strcmp(arg, "--objects")) {
1152                 revs->tag_objects = 1;
1153                 revs->tree_objects = 1;
1154                 revs->blob_objects = 1;
1155         } else if (!strcmp(arg, "--objects-edge")) {
1156                 revs->tag_objects = 1;
1157                 revs->tree_objects = 1;
1158                 revs->blob_objects = 1;
1159                 revs->edge_hint = 1;
1160         } else if (!strcmp(arg, "--unpacked")) {
1161                 revs->unpacked = 1;
1162         } else if (!prefixcmp(arg, "--unpacked=")) {
1163                 die("--unpacked=<packfile> no longer supported.");
1164         } else if (!strcmp(arg, "-r")) {
1165                 revs->diff = 1;
1166                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1167         } else if (!strcmp(arg, "-t")) {
1168                 revs->diff = 1;
1169                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1170                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1171         } else if (!strcmp(arg, "-m")) {
1172                 revs->ignore_merges = 0;
1173         } else if (!strcmp(arg, "-c")) {
1174                 revs->diff = 1;
1175                 revs->dense_combined_merges = 0;
1176                 revs->combine_merges = 1;
1177         } else if (!strcmp(arg, "--cc")) {
1178                 revs->diff = 1;
1179                 revs->dense_combined_merges = 1;
1180                 revs->combine_merges = 1;
1181         } else if (!strcmp(arg, "-v")) {
1182                 revs->verbose_header = 1;
1183         } else if (!strcmp(arg, "--pretty")) {
1184                 revs->verbose_header = 1;
1185                 revs->pretty_given = 1;
1186                 get_commit_format(arg+8, revs);
1187         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1188                 revs->verbose_header = 1;
1189                 revs->pretty_given = 1;
1190                 get_commit_format(arg+9, revs);
1191         } else if (!strcmp(arg, "--show-notes")) {
1192                 revs->show_notes = 1;
1193                 revs->show_notes_given = 1;
1194         } else if (!strcmp(arg, "--no-notes")) {
1195                 revs->show_notes = 0;
1196                 revs->show_notes_given = 1;
1197         } else if (!strcmp(arg, "--oneline")) {
1198                 revs->verbose_header = 1;
1199                 get_commit_format("oneline", revs);
1200                 revs->pretty_given = 1;
1201                 revs->abbrev_commit = 1;
1202         } else if (!strcmp(arg, "--graph")) {
1203                 revs->topo_order = 1;
1204                 revs->rewrite_parents = 1;
1205                 revs->graph = graph_init(revs);
1206         } else if (!strcmp(arg, "--root")) {
1207                 revs->show_root_diff = 1;
1208         } else if (!strcmp(arg, "--no-commit-id")) {
1209                 revs->no_commit_id = 1;
1210         } else if (!strcmp(arg, "--always")) {
1211                 revs->always_show_header = 1;
1212         } else if (!strcmp(arg, "--no-abbrev")) {
1213                 revs->abbrev = 0;
1214         } else if (!strcmp(arg, "--abbrev")) {
1215                 revs->abbrev = DEFAULT_ABBREV;
1216         } else if (!prefixcmp(arg, "--abbrev=")) {
1217                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1218                 if (revs->abbrev < MINIMUM_ABBREV)
1219                         revs->abbrev = MINIMUM_ABBREV;
1220                 else if (revs->abbrev > 40)
1221                         revs->abbrev = 40;
1222         } else if (!strcmp(arg, "--abbrev-commit")) {
1223                 revs->abbrev_commit = 1;
1224         } else if (!strcmp(arg, "--full-diff")) {
1225                 revs->diff = 1;
1226                 revs->full_diff = 1;
1227         } else if (!strcmp(arg, "--full-history")) {
1228                 revs->simplify_history = 0;
1229         } else if (!strcmp(arg, "--relative-date")) {
1230                 revs->date_mode = DATE_RELATIVE;
1231                 revs->date_mode_explicit = 1;
1232         } else if (!strncmp(arg, "--date=", 7)) {
1233                 revs->date_mode = parse_date_format(arg + 7);
1234                 revs->date_mode_explicit = 1;
1235         } else if (!strcmp(arg, "--log-size")) {
1236                 revs->show_log_size = 1;
1237         }
1238         /*
1239          * Grepping the commit log
1240          */
1241         else if (!prefixcmp(arg, "--author=")) {
1242                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1243         } else if (!prefixcmp(arg, "--committer=")) {
1244                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1245         } else if (!prefixcmp(arg, "--grep=")) {
1246                 add_message_grep(revs, arg+7);
1247         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1248                 revs->grep_filter.regflags |= REG_EXTENDED;
1249         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1250                 revs->grep_filter.regflags |= REG_ICASE;
1251         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1252                 revs->grep_filter.fixed = 1;
1253         } else if (!strcmp(arg, "--all-match")) {
1254                 revs->grep_filter.all_match = 1;
1255         } else if (!prefixcmp(arg, "--encoding=")) {
1256                 arg += 11;
1257                 if (strcmp(arg, "none"))
1258                         git_log_output_encoding = xstrdup(arg);
1259                 else
1260                         git_log_output_encoding = "";
1261         } else if (!strcmp(arg, "--reverse")) {
1262                 revs->reverse ^= 1;
1263         } else if (!strcmp(arg, "--children")) {
1264                 revs->children.name = "children";
1265                 revs->limited = 1;
1266         } else {
1267                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1268                 if (!opts)
1269                         unkv[(*unkc)++] = arg;
1270                 return opts;
1271         }
1272
1273         return 1;
1274 }
1275
1276 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1277                         const struct option *options,
1278                         const char * const usagestr[])
1279 {
1280         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1281                                     &ctx->cpidx, ctx->out);
1282         if (n <= 0) {
1283                 error("unknown option `%s'", ctx->argv[0]);
1284                 usage_with_options(usagestr, options);
1285         }
1286         ctx->argv += n;
1287         ctx->argc -= n;
1288 }
1289
1290 static int for_each_bad_bisect_ref(each_ref_fn fn, void *cb_data)
1291 {
1292         return for_each_ref_in("refs/bisect/bad", fn, cb_data);
1293 }
1294
1295 static int for_each_good_bisect_ref(each_ref_fn fn, void *cb_data)
1296 {
1297         return for_each_ref_in("refs/bisect/good", fn, cb_data);
1298 }
1299
1300 static void append_prune_data(const char ***prune_data, const char **av)
1301 {
1302         const char **prune = *prune_data;
1303         int prune_nr;
1304         int prune_alloc;
1305
1306         if (!prune) {
1307                 *prune_data = av;
1308                 return;
1309         }
1310
1311         /* count existing ones */
1312         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1313                 ;
1314         prune_alloc = prune_nr; /* not really, but we do not know */
1315
1316         while (*av) {
1317                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1318                 prune[prune_nr++] = *av;
1319                 av++;
1320         }
1321         if (prune) {
1322                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1323                 prune[prune_nr] = NULL;
1324         }
1325         *prune_data = prune;
1326 }
1327
1328 /*
1329  * Parse revision information, filling in the "rev_info" structure,
1330  * and removing the used arguments from the argument list.
1331  *
1332  * Returns the number of arguments left that weren't recognized
1333  * (which are also moved to the head of the argument list)
1334  */
1335 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
1336 {
1337         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1338         const char **prune_data = NULL;
1339
1340         /* First, search for "--" */
1341         seen_dashdash = 0;
1342         for (i = 1; i < argc; i++) {
1343                 const char *arg = argv[i];
1344                 if (strcmp(arg, "--"))
1345                         continue;
1346                 argv[i] = NULL;
1347                 argc = i;
1348                 if (argv[i + 1])
1349                         prune_data = argv + i + 1;
1350                 seen_dashdash = 1;
1351                 break;
1352         }
1353
1354         /* Second, deal with arguments and options */
1355         flags = 0;
1356         read_from_stdin = 0;
1357         for (left = i = 1; i < argc; i++) {
1358                 const char *arg = argv[i];
1359                 if (*arg == '-') {
1360                         int opts;
1361
1362                         if (!strcmp(arg, "--all")) {
1363                                 handle_refs(revs, flags, for_each_ref);
1364                                 handle_refs(revs, flags, head_ref);
1365                                 continue;
1366                         }
1367                         if (!strcmp(arg, "--branches")) {
1368                                 handle_refs(revs, flags, for_each_branch_ref);
1369                                 continue;
1370                         }
1371                         if (!strcmp(arg, "--bisect")) {
1372                                 handle_refs(revs, flags, for_each_bad_bisect_ref);
1373                                 handle_refs(revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1374                                 revs->bisect = 1;
1375                                 continue;
1376                         }
1377                         if (!strcmp(arg, "--tags")) {
1378                                 handle_refs(revs, flags, for_each_tag_ref);
1379                                 continue;
1380                         }
1381                         if (!strcmp(arg, "--remotes")) {
1382                                 handle_refs(revs, flags, for_each_remote_ref);
1383                                 continue;
1384                         }
1385                         if (!prefixcmp(arg, "--glob=")) {
1386                                 struct all_refs_cb cb;
1387                                 init_all_refs_cb(&cb, revs, flags);
1388                                 for_each_glob_ref(handle_one_ref, arg + 7, &cb);
1389                                 continue;
1390                         }
1391                         if (!prefixcmp(arg, "--branches=")) {
1392                                 struct all_refs_cb cb;
1393                                 init_all_refs_cb(&cb, revs, flags);
1394                                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1395                                 continue;
1396                         }
1397                         if (!prefixcmp(arg, "--tags=")) {
1398                                 struct all_refs_cb cb;
1399                                 init_all_refs_cb(&cb, revs, flags);
1400                                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1401                                 continue;
1402                         }
1403                         if (!prefixcmp(arg, "--remotes=")) {
1404                                 struct all_refs_cb cb;
1405                                 init_all_refs_cb(&cb, revs, flags);
1406                                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1407                                 continue;
1408                         }
1409                         if (!strcmp(arg, "--reflog")) {
1410                                 handle_reflog(revs, flags);
1411                                 continue;
1412                         }
1413                         if (!strcmp(arg, "--not")) {
1414                                 flags ^= UNINTERESTING;
1415                                 continue;
1416                         }
1417                         if (!strcmp(arg, "--no-walk")) {
1418                                 revs->no_walk = 1;
1419                                 continue;
1420                         }
1421                         if (!strcmp(arg, "--do-walk")) {
1422                                 revs->no_walk = 0;
1423                                 continue;
1424                         }
1425                         if (!strcmp(arg, "--stdin")) {
1426                                 if (revs->disable_stdin) {
1427                                         argv[left++] = arg;
1428                                         continue;
1429                                 }
1430                                 if (read_from_stdin++)
1431                                         die("--stdin given twice?");
1432                                 read_revisions_from_stdin(revs, &prune_data);
1433                                 continue;
1434                         }
1435
1436                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1437                         if (opts > 0) {
1438                                 i += opts - 1;
1439                                 continue;
1440                         }
1441                         if (opts < 0)
1442                                 exit(128);
1443                         continue;
1444                 }
1445
1446                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1447                         int j;
1448                         if (seen_dashdash || *arg == '^')
1449                                 die("bad revision '%s'", arg);
1450
1451                         /* If we didn't have a "--":
1452                          * (1) all filenames must exist;
1453                          * (2) all rev-args must not be interpretable
1454                          *     as a valid filename.
1455                          * but the latter we have checked in the main loop.
1456                          */
1457                         for (j = i; j < argc; j++)
1458                                 verify_filename(revs->prefix, argv[j]);
1459
1460                         append_prune_data(&prune_data, argv + i);
1461                         break;
1462                 }
1463                 else
1464                         got_rev_arg = 1;
1465         }
1466
1467         if (prune_data)
1468                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1469
1470         if (revs->def == NULL)
1471                 revs->def = def;
1472         if (revs->show_merge)
1473                 prepare_show_merge(revs);
1474         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1475                 unsigned char sha1[20];
1476                 struct object *object;
1477                 unsigned mode;
1478                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1479                         die("bad default revision '%s'", revs->def);
1480                 object = get_reference(revs, revs->def, sha1, 0);
1481                 add_pending_object_with_mode(revs, object, revs->def, mode);
1482         }
1483
1484         /* Did the user ask for any diff output? Run the diff! */
1485         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1486                 revs->diff = 1;
1487
1488         /* Pickaxe, diff-filter and rename following need diffs */
1489         if (revs->diffopt.pickaxe ||
1490             revs->diffopt.filter ||
1491             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1492                 revs->diff = 1;
1493
1494         if (revs->topo_order)
1495                 revs->limited = 1;
1496
1497         if (revs->prune_data) {
1498                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1499                 /* Can't prune commits with rename following: the paths change.. */
1500                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1501                         revs->prune = 1;
1502                 if (!revs->full_diff)
1503                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1504         }
1505         if (revs->combine_merges) {
1506                 revs->ignore_merges = 0;
1507                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1508                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1509         }
1510         revs->diffopt.abbrev = revs->abbrev;
1511         if (diff_setup_done(&revs->diffopt) < 0)
1512                 die("diff_setup_done failed");
1513
1514         compile_grep_patterns(&revs->grep_filter);
1515
1516         if (revs->reverse && revs->reflog_info)
1517                 die("cannot combine --reverse with --walk-reflogs");
1518         if (revs->rewrite_parents && revs->children.name)
1519                 die("cannot combine --parents and --children");
1520
1521         /*
1522          * Limitations on the graph functionality
1523          */
1524         if (revs->reverse && revs->graph)
1525                 die("cannot combine --reverse with --graph");
1526
1527         if (revs->reflog_info && revs->graph)
1528                 die("cannot combine --walk-reflogs with --graph");
1529
1530         return left;
1531 }
1532
1533 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1534 {
1535         struct commit_list *l = xcalloc(1, sizeof(*l));
1536
1537         l->item = child;
1538         l->next = add_decoration(&revs->children, &parent->object, l);
1539 }
1540
1541 static int remove_duplicate_parents(struct commit *commit)
1542 {
1543         struct commit_list **pp, *p;
1544         int surviving_parents;
1545
1546         /* Examine existing parents while marking ones we have seen... */
1547         pp = &commit->parents;
1548         while ((p = *pp) != NULL) {
1549                 struct commit *parent = p->item;
1550                 if (parent->object.flags & TMP_MARK) {
1551                         *pp = p->next;
1552                         continue;
1553                 }
1554                 parent->object.flags |= TMP_MARK;
1555                 pp = &p->next;
1556         }
1557         /* count them while clearing the temporary mark */
1558         surviving_parents = 0;
1559         for (p = commit->parents; p; p = p->next) {
1560                 p->item->object.flags &= ~TMP_MARK;
1561                 surviving_parents++;
1562         }
1563         return surviving_parents;
1564 }
1565
1566 struct merge_simplify_state {
1567         struct commit *simplified;
1568 };
1569
1570 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1571 {
1572         struct merge_simplify_state *st;
1573
1574         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1575         if (!st) {
1576                 st = xcalloc(1, sizeof(*st));
1577                 add_decoration(&revs->merge_simplification, &commit->object, st);
1578         }
1579         return st;
1580 }
1581
1582 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1583 {
1584         struct commit_list *p;
1585         struct merge_simplify_state *st, *pst;
1586         int cnt;
1587
1588         st = locate_simplify_state(revs, commit);
1589
1590         /*
1591          * Have we handled this one?
1592          */
1593         if (st->simplified)
1594                 return tail;
1595
1596         /*
1597          * An UNINTERESTING commit simplifies to itself, so does a
1598          * root commit.  We do not rewrite parents of such commit
1599          * anyway.
1600          */
1601         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1602                 st->simplified = commit;
1603                 return tail;
1604         }
1605
1606         /*
1607          * Do we know what commit all of our parents should be rewritten to?
1608          * Otherwise we are not ready to rewrite this one yet.
1609          */
1610         for (cnt = 0, p = commit->parents; p; p = p->next) {
1611                 pst = locate_simplify_state(revs, p->item);
1612                 if (!pst->simplified) {
1613                         tail = &commit_list_insert(p->item, tail)->next;
1614                         cnt++;
1615                 }
1616         }
1617         if (cnt) {
1618                 tail = &commit_list_insert(commit, tail)->next;
1619                 return tail;
1620         }
1621
1622         /*
1623          * Rewrite our list of parents.
1624          */
1625         for (p = commit->parents; p; p = p->next) {
1626                 pst = locate_simplify_state(revs, p->item);
1627                 p->item = pst->simplified;
1628         }
1629         cnt = remove_duplicate_parents(commit);
1630
1631         /*
1632          * It is possible that we are a merge and one side branch
1633          * does not have any commit that touches the given paths;
1634          * in such a case, the immediate parents will be rewritten
1635          * to different commits.
1636          *
1637          *      o----X          X: the commit we are looking at;
1638          *     /    /           o: a commit that touches the paths;
1639          * ---o----'
1640          *
1641          * Further reduce the parents by removing redundant parents.
1642          */
1643         if (1 < cnt) {
1644                 struct commit_list *h = reduce_heads(commit->parents);
1645                 cnt = commit_list_count(h);
1646                 free_commit_list(commit->parents);
1647                 commit->parents = h;
1648         }
1649
1650         /*
1651          * A commit simplifies to itself if it is a root, if it is
1652          * UNINTERESTING, if it touches the given paths, or if it is a
1653          * merge and its parents simplifies to more than one commits
1654          * (the first two cases are already handled at the beginning of
1655          * this function).
1656          *
1657          * Otherwise, it simplifies to what its sole parent simplifies to.
1658          */
1659         if (!cnt ||
1660             (commit->object.flags & UNINTERESTING) ||
1661             !(commit->object.flags & TREESAME) ||
1662             (1 < cnt))
1663                 st->simplified = commit;
1664         else {
1665                 pst = locate_simplify_state(revs, commit->parents->item);
1666                 st->simplified = pst->simplified;
1667         }
1668         return tail;
1669 }
1670
1671 static void simplify_merges(struct rev_info *revs)
1672 {
1673         struct commit_list *list;
1674         struct commit_list *yet_to_do, **tail;
1675
1676         if (!revs->topo_order)
1677                 sort_in_topological_order(&revs->commits, revs->lifo);
1678         if (!revs->prune)
1679                 return;
1680
1681         /* feed the list reversed */
1682         yet_to_do = NULL;
1683         for (list = revs->commits; list; list = list->next)
1684                 commit_list_insert(list->item, &yet_to_do);
1685         while (yet_to_do) {
1686                 list = yet_to_do;
1687                 yet_to_do = NULL;
1688                 tail = &yet_to_do;
1689                 while (list) {
1690                         struct commit *commit = list->item;
1691                         struct commit_list *next = list->next;
1692                         free(list);
1693                         list = next;
1694                         tail = simplify_one(revs, commit, tail);
1695                 }
1696         }
1697
1698         /* clean up the result, removing the simplified ones */
1699         list = revs->commits;
1700         revs->commits = NULL;
1701         tail = &revs->commits;
1702         while (list) {
1703                 struct commit *commit = list->item;
1704                 struct commit_list *next = list->next;
1705                 struct merge_simplify_state *st;
1706                 free(list);
1707                 list = next;
1708                 st = locate_simplify_state(revs, commit);
1709                 if (st->simplified == commit)
1710                         tail = &commit_list_insert(commit, tail)->next;
1711         }
1712 }
1713
1714 static void set_children(struct rev_info *revs)
1715 {
1716         struct commit_list *l;
1717         for (l = revs->commits; l; l = l->next) {
1718                 struct commit *commit = l->item;
1719                 struct commit_list *p;
1720
1721                 for (p = commit->parents; p; p = p->next)
1722                         add_child(revs, p->item, commit);
1723         }
1724 }
1725
1726 int prepare_revision_walk(struct rev_info *revs)
1727 {
1728         int nr = revs->pending.nr;
1729         struct object_array_entry *e, *list;
1730
1731         e = list = revs->pending.objects;
1732         revs->pending.nr = 0;
1733         revs->pending.alloc = 0;
1734         revs->pending.objects = NULL;
1735         while (--nr >= 0) {
1736                 struct commit *commit = handle_commit(revs, e->item, e->name);
1737                 if (commit) {
1738                         if (!(commit->object.flags & SEEN)) {
1739                                 commit->object.flags |= SEEN;
1740                                 insert_by_date(commit, &revs->commits);
1741                         }
1742                 }
1743                 e++;
1744         }
1745         free(list);
1746
1747         if (revs->no_walk)
1748                 return 0;
1749         if (revs->limited)
1750                 if (limit_list(revs) < 0)
1751                         return -1;
1752         if (revs->topo_order)
1753                 sort_in_topological_order(&revs->commits, revs->lifo);
1754         if (revs->simplify_merges)
1755                 simplify_merges(revs);
1756         if (revs->children.name)
1757                 set_children(revs);
1758         return 0;
1759 }
1760
1761 enum rewrite_result {
1762         rewrite_one_ok,
1763         rewrite_one_noparents,
1764         rewrite_one_error,
1765 };
1766
1767 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1768 {
1769         struct commit_list *cache = NULL;
1770
1771         for (;;) {
1772                 struct commit *p = *pp;
1773                 if (!revs->limited)
1774                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1775                                 return rewrite_one_error;
1776                 if (p->parents && p->parents->next)
1777                         return rewrite_one_ok;
1778                 if (p->object.flags & UNINTERESTING)
1779                         return rewrite_one_ok;
1780                 if (!(p->object.flags & TREESAME))
1781                         return rewrite_one_ok;
1782                 if (!p->parents)
1783                         return rewrite_one_noparents;
1784                 *pp = p->parents->item;
1785         }
1786 }
1787
1788 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1789 {
1790         struct commit_list **pp = &commit->parents;
1791         while (*pp) {
1792                 struct commit_list *parent = *pp;
1793                 switch (rewrite_one(revs, &parent->item)) {
1794                 case rewrite_one_ok:
1795                         break;
1796                 case rewrite_one_noparents:
1797                         *pp = parent->next;
1798                         continue;
1799                 case rewrite_one_error:
1800                         return -1;
1801                 }
1802                 pp = &parent->next;
1803         }
1804         remove_duplicate_parents(commit);
1805         return 0;
1806 }
1807
1808 static int commit_match(struct commit *commit, struct rev_info *opt)
1809 {
1810         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
1811                 return 1;
1812         return grep_buffer(&opt->grep_filter,
1813                            NULL, /* we say nothing, not even filename */
1814                            commit->buffer, strlen(commit->buffer));
1815 }
1816
1817 static inline int want_ancestry(struct rev_info *revs)
1818 {
1819         return (revs->rewrite_parents || revs->children.name);
1820 }
1821
1822 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1823 {
1824         if (commit->object.flags & SHOWN)
1825                 return commit_ignore;
1826         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1827                 return commit_ignore;
1828         if (revs->show_all)
1829                 return commit_show;
1830         if (commit->object.flags & UNINTERESTING)
1831                 return commit_ignore;
1832         if (revs->min_age != -1 && (commit->date > revs->min_age))
1833                 return commit_ignore;
1834         if (revs->no_merges && commit->parents && commit->parents->next)
1835                 return commit_ignore;
1836         if (revs->merges_only && !(commit->parents && commit->parents->next))
1837                 return commit_ignore;
1838         if (!commit_match(commit, revs))
1839                 return commit_ignore;
1840         if (revs->prune && revs->dense) {
1841                 /* Commit without changes? */
1842                 if (commit->object.flags & TREESAME) {
1843                         /* drop merges unless we want parenthood */
1844                         if (!want_ancestry(revs))
1845                                 return commit_ignore;
1846                         /* non-merge - always ignore it */
1847                         if (!commit->parents || !commit->parents->next)
1848                                 return commit_ignore;
1849                 }
1850         }
1851         return commit_show;
1852 }
1853
1854 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1855 {
1856         enum commit_action action = get_commit_action(revs, commit);
1857
1858         if (action == commit_show &&
1859             !revs->show_all &&
1860             revs->prune && revs->dense && want_ancestry(revs)) {
1861                 if (rewrite_parents(revs, commit) < 0)
1862                         return commit_error;
1863         }
1864         return action;
1865 }
1866
1867 static struct commit *get_revision_1(struct rev_info *revs)
1868 {
1869         if (!revs->commits)
1870                 return NULL;
1871
1872         do {
1873                 struct commit_list *entry = revs->commits;
1874                 struct commit *commit = entry->item;
1875
1876                 revs->commits = entry->next;
1877                 free(entry);
1878
1879                 if (revs->reflog_info)
1880                         fake_reflog_parent(revs->reflog_info, commit);
1881
1882                 /*
1883                  * If we haven't done the list limiting, we need to look at
1884                  * the parents here. We also need to do the date-based limiting
1885                  * that we'd otherwise have done in limit_list().
1886                  */
1887                 if (!revs->limited) {
1888                         if (revs->max_age != -1 &&
1889                             (commit->date < revs->max_age))
1890                                 continue;
1891                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1892                                 die("Failed to traverse parents of commit %s",
1893                                     sha1_to_hex(commit->object.sha1));
1894                 }
1895
1896                 switch (simplify_commit(revs, commit)) {
1897                 case commit_ignore:
1898                         continue;
1899                 case commit_error:
1900                         die("Failed to simplify parents of commit %s",
1901                             sha1_to_hex(commit->object.sha1));
1902                 default:
1903                         return commit;
1904                 }
1905         } while (revs->commits);
1906         return NULL;
1907 }
1908
1909 static void gc_boundary(struct object_array *array)
1910 {
1911         unsigned nr = array->nr;
1912         unsigned alloc = array->alloc;
1913         struct object_array_entry *objects = array->objects;
1914
1915         if (alloc <= nr) {
1916                 unsigned i, j;
1917                 for (i = j = 0; i < nr; i++) {
1918                         if (objects[i].item->flags & SHOWN)
1919                                 continue;
1920                         if (i != j)
1921                                 objects[j] = objects[i];
1922                         j++;
1923                 }
1924                 for (i = j; i < nr; i++)
1925                         objects[i].item = NULL;
1926                 array->nr = j;
1927         }
1928 }
1929
1930 static void create_boundary_commit_list(struct rev_info *revs)
1931 {
1932         unsigned i;
1933         struct commit *c;
1934         struct object_array *array = &revs->boundary_commits;
1935         struct object_array_entry *objects = array->objects;
1936
1937         /*
1938          * If revs->commits is non-NULL at this point, an error occurred in
1939          * get_revision_1().  Ignore the error and continue printing the
1940          * boundary commits anyway.  (This is what the code has always
1941          * done.)
1942          */
1943         if (revs->commits) {
1944                 free_commit_list(revs->commits);
1945                 revs->commits = NULL;
1946         }
1947
1948         /*
1949          * Put all of the actual boundary commits from revs->boundary_commits
1950          * into revs->commits
1951          */
1952         for (i = 0; i < array->nr; i++) {
1953                 c = (struct commit *)(objects[i].item);
1954                 if (!c)
1955                         continue;
1956                 if (!(c->object.flags & CHILD_SHOWN))
1957                         continue;
1958                 if (c->object.flags & (SHOWN | BOUNDARY))
1959                         continue;
1960                 c->object.flags |= BOUNDARY;
1961                 commit_list_insert(c, &revs->commits);
1962         }
1963
1964         /*
1965          * If revs->topo_order is set, sort the boundary commits
1966          * in topological order
1967          */
1968         sort_in_topological_order(&revs->commits, revs->lifo);
1969 }
1970
1971 static struct commit *get_revision_internal(struct rev_info *revs)
1972 {
1973         struct commit *c = NULL;
1974         struct commit_list *l;
1975
1976         if (revs->boundary == 2) {
1977                 /*
1978                  * All of the normal commits have already been returned,
1979                  * and we are now returning boundary commits.
1980                  * create_boundary_commit_list() has populated
1981                  * revs->commits with the remaining commits to return.
1982                  */
1983                 c = pop_commit(&revs->commits);
1984                 if (c)
1985                         c->object.flags |= SHOWN;
1986                 return c;
1987         }
1988
1989         /*
1990          * Now pick up what they want to give us
1991          */
1992         c = get_revision_1(revs);
1993         if (c) {
1994                 while (0 < revs->skip_count) {
1995                         revs->skip_count--;
1996                         c = get_revision_1(revs);
1997                         if (!c)
1998                                 break;
1999                 }
2000         }
2001
2002         /*
2003          * Check the max_count.
2004          */
2005         switch (revs->max_count) {
2006         case -1:
2007                 break;
2008         case 0:
2009                 c = NULL;
2010                 break;
2011         default:
2012                 revs->max_count--;
2013         }
2014
2015         if (c)
2016                 c->object.flags |= SHOWN;
2017
2018         if (!revs->boundary) {
2019                 return c;
2020         }
2021
2022         if (!c) {
2023                 /*
2024                  * get_revision_1() runs out the commits, and
2025                  * we are done computing the boundaries.
2026                  * switch to boundary commits output mode.
2027                  */
2028                 revs->boundary = 2;
2029
2030                 /*
2031                  * Update revs->commits to contain the list of
2032                  * boundary commits.
2033                  */
2034                 create_boundary_commit_list(revs);
2035
2036                 return get_revision_internal(revs);
2037         }
2038
2039         /*
2040          * boundary commits are the commits that are parents of the
2041          * ones we got from get_revision_1() but they themselves are
2042          * not returned from get_revision_1().  Before returning
2043          * 'c', we need to mark its parents that they could be boundaries.
2044          */
2045
2046         for (l = c->parents; l; l = l->next) {
2047                 struct object *p;
2048                 p = &(l->item->object);
2049                 if (p->flags & (CHILD_SHOWN | SHOWN))
2050                         continue;
2051                 p->flags |= CHILD_SHOWN;
2052                 gc_boundary(&revs->boundary_commits);
2053                 add_object_array(p, NULL, &revs->boundary_commits);
2054         }
2055
2056         return c;
2057 }
2058
2059 struct commit *get_revision(struct rev_info *revs)
2060 {
2061         struct commit *c;
2062         struct commit_list *reversed;
2063
2064         if (revs->reverse) {
2065                 reversed = NULL;
2066                 while ((c = get_revision_internal(revs))) {
2067                         commit_list_insert(c, &reversed);
2068                 }
2069                 revs->commits = reversed;
2070                 revs->reverse = 0;
2071                 revs->reverse_output_stage = 1;
2072         }
2073
2074         if (revs->reverse_output_stage)
2075                 return pop_commit(&revs->commits);
2076
2077         c = get_revision_internal(revs);
2078         if (c && revs->graph)
2079                 graph_update(revs->graph, c);
2080         return c;
2081 }