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 #include "string-list.h"
  16
  17 volatile show_early_output_fn_t show_early_output;
  18
  19 char *path_name(const struct name_path *path, const char *name)
  20 {
  21         const struct name_path *p;
  22         char *n, *m;
  23         int nlen = strlen(name);
  24         int len = nlen + 1;
  25
  26         for (p = path; p; p = p->up) {
  27                 if (p->elem_len)
  28                         len += p->elem_len + 1;
  29         }
  30         n = xmalloc(len);
  31         m = n + len - (nlen + 1);
  32         strcpy(m, name);
  33         for (p = path; p; p = p->up) {
  34                 if (p->elem_len) {
  35                         m -= p->elem_len + 1;
  36                         memcpy(m, p->elem, p->elem_len);
  37                         m[p->elem_len] = '/';
  38                 }
  39         }
  40         return n;
  41 }
  42
  43 void add_object(struct object *obj,
  44                 struct object_array *p,
  45                 struct name_path *path,
  46                 const char *name)
  47 {
  48         add_object_array(obj, path_name(path, name), p);
  49 }
  50
  51 static void mark_blob_uninteresting(struct blob *blob)
  52 {
  53         if (!blob)
  54                 return;
  55         if (blob->object.flags & UNINTERESTING)
  56                 return;
  57         blob->object.flags |= UNINTERESTING;
  58 }
  59
  60 void mark_tree_uninteresting(struct tree *tree)
  61 {
  62         struct tree_desc desc;
  63         struct name_entry entry;
  64         struct object *obj = &tree->object;
  65
  66         if (!tree)
  67                 return;
  68         if (obj->flags & UNINTERESTING)
  69                 return;
  70         obj->flags |= UNINTERESTING;
  71         if (!has_sha1_file(obj->sha1))
  72                 return;
  73         if (parse_tree(tree) < 0)
  74                 die("bad tree %s", sha1_to_hex(obj->sha1));
  75
  76         init_tree_desc(&desc, tree->buffer, tree->size);
  77         while (tree_entry(&desc, &entry)) {
  78                 switch (object_type(entry.mode)) {
  79                 case OBJ_TREE:
  80                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  81                         break;
  82                 case OBJ_BLOB:
  83                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  84                         break;
  85                 default:
  86                         /* Subproject commit - not in this repository */
  87                         break;
  88                 }
  89         }
  90
  91         /*
  92          * We don't care about the tree any more
  93          * after it has been marked uninteresting.
  94          */
  95         free(tree->buffer);
  96         tree->buffer = NULL;
  97 }
  98
  99 void mark_parents_uninteresting(struct commit *commit)
 100 {
 101         struct commit_list *parents = commit->parents;
 102
 103         while (parents) {
 104                 struct commit *commit = parents->item;
 105                 if (!(commit->object.flags & UNINTERESTING)) {
 106                         commit->object.flags |= UNINTERESTING;
 107
 108                         /*
 109                          * Normally we haven't parsed the parent
 110                          * yet, so we won't have a parent of a parent
 111                          * here. However, it may turn out that we've
 112                          * reached this commit some other way (where it
 113                          * wasn't uninteresting), in which case we need
 114                          * to mark its parents recursively too..
 115                          */
 116                         if (commit->parents)
 117                                 mark_parents_uninteresting(commit);
 118                 }
 119
 120                 /*
 121                  * A missing commit is ok iff its parent is marked
 122                  * uninteresting.
 123                  *
 124                  * We just mark such a thing parsed, so that when
 125                  * it is popped next time around, we won't be trying
 126                  * to parse it and get an error.
 127                  */
 128                 if (!has_sha1_file(commit->object.sha1))
 129                         commit->object.parsed = 1;
 130                 parents = parents->next;
 131         }
 132 }
 133
 134 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 135 {
 136         if (revs->no_walk && (obj->flags & UNINTERESTING))
 137                 revs->no_walk = 0;
 138         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 139                 struct strbuf buf = STRBUF_INIT;
 140                 int len = interpret_branch_name(name, &buf);
 141                 int st;
 142
 143                 if (0 < len && name[len] && buf.len)
 144                         strbuf_addstr(&buf, name + len);
 145                 st = add_reflog_for_walk(revs->reflog_info,
 146                                          (struct commit *)obj,
 147                                          buf.buf[0] ? buf.buf: name);
 148                 strbuf_release(&buf);
 149                 if (st)
 150                         return;
 151         }
 152         add_object_array_with_mode(obj, name, &revs->pending, mode);
 153 }
 154
 155 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 156 {
 157         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 158 }
 159
 160 void add_head_to_pending(struct rev_info *revs)
 161 {
 162         unsigned char sha1[20];
 163         struct object *obj;
 164         if (get_sha1("HEAD", sha1))
 165                 return;
 166         obj = parse_object(sha1);
 167         if (!obj)
 168                 return;
 169         add_pending_object(revs, obj, "HEAD");
 170 }
 171
 172 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 173 {
 174         struct object *object;
 175
 176         object = parse_object(sha1);
 177         if (!object)
 178                 die("bad object %s", name);
 179         object->flags |= flags;
 180         return object;
 181 }
 182
 183 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 184 {
 185         unsigned long flags = object->flags;
 186
 187         /*
 188          * Tag object? Look what it points to..
 189          */
 190         while (object->type == OBJ_TAG) {
 191                 struct tag *tag = (struct tag *) object;
 192                 if (revs->tag_objects && !(flags & UNINTERESTING))
 193                         add_pending_object(revs, object, tag->tag);
 194                 if (!tag->tagged)
 195                         die("bad tag");
 196                 object = parse_object(tag->tagged->sha1);
 197                 if (!object) {
 198                         if (flags & UNINTERESTING)
 199                                 return NULL;
 200                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 201                 }
 202         }
 203
 204         /*
 205          * Commit object? Just return it, we'll do all the complex
 206          * reachability crud.
 207          */
 208         if (object->type == OBJ_COMMIT) {
 209                 struct commit *commit = (struct commit *)object;
 210                 if (parse_commit(commit) < 0)
 211                         die("unable to parse commit %s", name);
 212                 if (flags & UNINTERESTING) {
 213                         commit->object.flags |= UNINTERESTING;
 214                         mark_parents_uninteresting(commit);
 215                         revs->limited = 1;
 216                 }
 217                 if (revs->show_source && !commit->util)
 218                         commit->util = (void *) name;
 219                 return commit;
 220         }
 221
 222         /*
 223          * Tree object? Either mark it uninteresting, or add it
 224          * to the list of objects to look at later..
 225          */
 226         if (object->type == OBJ_TREE) {
 227                 struct tree *tree = (struct tree *)object;
 228                 if (!revs->tree_objects)
 229                         return NULL;
 230                 if (flags & UNINTERESTING) {
 231                         mark_tree_uninteresting(tree);
 232                         return NULL;
 233                 }
 234                 add_pending_object(revs, object, "");
 235                 return NULL;
 236         }
 237
 238         /*
 239          * Blob object? You know the drill by now..
 240          */
 241         if (object->type == OBJ_BLOB) {
 242                 struct blob *blob = (struct blob *)object;
 243                 if (!revs->blob_objects)
 244                         return NULL;
 245                 if (flags & UNINTERESTING) {
 246                         mark_blob_uninteresting(blob);
 247                         return NULL;
 248                 }
 249                 add_pending_object(revs, object, "");
 250                 return NULL;
 251         }
 252         die("%s is unknown object", name);
 253 }
 254
 255 static int everybody_uninteresting(struct commit_list *orig)
 256 {
 257         struct commit_list *list = orig;
 258         while (list) {
 259                 struct commit *commit = list->item;
 260                 list = list->next;
 261                 if (commit->object.flags & UNINTERESTING)
 262                         continue;
 263                 return 0;
 264         }
 265         return 1;
 266 }
 267
 268 /*
 269  * The goal is to get REV_TREE_NEW as the result only if the
 270  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 271  * if the whole diff is removal of old data, and otherwise
 272  * REV_TREE_DIFFERENT (of course if the trees are the same we
 273  * want REV_TREE_SAME).
 274  * That means that once we get to REV_TREE_DIFFERENT, we do not
 275  * have to look any further.
 276  */
 277 static int tree_difference = REV_TREE_SAME;
 278
 279 static void file_add_remove(struct diff_options *options,
 280                     int addremove, unsigned mode,
 281                     const unsigned char *sha1,
 282                     const char *fullpath, unsigned dirty_submodule)
 283 {
 284         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 285
 286         tree_difference |= diff;
 287         if (tree_difference == REV_TREE_DIFFERENT)
 288                 DIFF_OPT_SET(options, HAS_CHANGES);
 289 }
 290
 291 static void file_change(struct diff_options *options,
 292                  unsigned old_mode, unsigned new_mode,
 293                  const unsigned char *old_sha1,
 294                  const unsigned char *new_sha1,
 295                  const char *fullpath,
 296                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 297 {
 298         tree_difference = REV_TREE_DIFFERENT;
 299         DIFF_OPT_SET(options, HAS_CHANGES);
 300 }
 301
 302 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 303 {
 304         struct tree *t1 = parent->tree;
 305         struct tree *t2 = commit->tree;
 306
 307         if (!t1)
 308                 return REV_TREE_NEW;
 309         if (!t2)
 310                 return REV_TREE_OLD;
 311
 312         if (revs->simplify_by_decoration) {
 313                 /*
 314                  * If we are simplifying by decoration, then the commit
 315                  * is worth showing if it has a tag pointing at it.
 316                  */
 317                 if (lookup_decoration(&name_decoration, &commit->object))
 318                         return REV_TREE_DIFFERENT;
 319                 /*
 320                  * A commit that is not pointed by a tag is uninteresting
 321                  * if we are not limited by path.  This means that you will
 322                  * see the usual "commits that touch the paths" plus any
 323                  * tagged commit by specifying both --simplify-by-decoration
 324                  * and pathspec.
 325                  */
 326                 if (!revs->prune_data)
 327                         return REV_TREE_SAME;
 328         }
 329
 330         tree_difference = REV_TREE_SAME;
 331         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 332         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 333                            &revs->pruning) < 0)
 334                 return REV_TREE_DIFFERENT;
 335         return tree_difference;
 336 }
 337
 338 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 339 {
 340         int retval;
 341         void *tree;
 342         unsigned long size;
 343         struct tree_desc empty, real;
 344         struct tree *t1 = commit->tree;
 345
 346         if (!t1)
 347                 return 0;
 348
 349         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 350         if (!tree)
 351                 return 0;
 352         init_tree_desc(&real, tree, size);
 353         init_tree_desc(&empty, "", 0);
 354
 355         tree_difference = REV_TREE_SAME;
 356         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 357         retval = diff_tree(&empty, &real, "", &revs->pruning);
 358         free(tree);
 359
 360         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 361 }
 362
 363 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 364 {
 365         struct commit_list **pp, *parent;
 366         int tree_changed = 0, tree_same = 0;
 367
 368         /*
 369          * If we don't do pruning, everything is interesting
 370          */
 371         if (!revs->prune)
 372                 return;
 373
 374         if (!commit->tree)
 375                 return;
 376
 377         if (!commit->parents) {
 378                 if (rev_same_tree_as_empty(revs, commit))
 379                         commit->object.flags |= TREESAME;
 380                 return;
 381         }
 382
 383         /*
 384          * Normal non-merge commit? If we don't want to make the
 385          * history dense, we consider it always to be a change..
 386          */
 387         if (!revs->dense && !commit->parents->next)
 388                 return;
 389
 390         pp = &commit->parents;
 391         while ((parent = *pp) != NULL) {
 392                 struct commit *p = parent->item;
 393
 394                 if (parse_commit(p) < 0)
 395                         die("cannot simplify commit %s (because of %s)",
 396                             sha1_to_hex(commit->object.sha1),
 397                             sha1_to_hex(p->object.sha1));
 398                 switch (rev_compare_tree(revs, p, commit)) {
 399                 case REV_TREE_SAME:
 400                         tree_same = 1;
 401                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 402                                 /* Even if a merge with an uninteresting
 403                                  * side branch brought the entire change
 404                                  * we are interested in, we do not want
 405                                  * to lose the other branches of this
 406                                  * merge, so we just keep going.
 407                                  */
 408                                 pp = &parent->next;
 409                                 continue;
 410                         }
 411                         parent->next = NULL;
 412                         commit->parents = parent;
 413                         commit->object.flags |= TREESAME;
 414                         return;
 415
 416                 case REV_TREE_NEW:
 417                         if (revs->remove_empty_trees &&
 418                             rev_same_tree_as_empty(revs, p)) {
 419                                 /* We are adding all the specified
 420                                  * paths from this parent, so the
 421                                  * history beyond this parent is not
 422                                  * interesting.  Remove its parents
 423                                  * (they are grandparents for us).
 424                                  * IOW, we pretend this parent is a
 425                                  * "root" commit.
 426                                  */
 427                                 if (parse_commit(p) < 0)
 428                                         die("cannot simplify commit %s (invalid %s)",
 429                                             sha1_to_hex(commit->object.sha1),
 430                                             sha1_to_hex(p->object.sha1));
 431                                 p->parents = NULL;
 432                         }
 433                 /* fallthrough */
 434                 case REV_TREE_OLD:
 435                 case REV_TREE_DIFFERENT:
 436                         tree_changed = 1;
 437                         pp = &parent->next;
 438                         continue;
 439                 }
 440                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 441         }
 442         if (tree_changed && !tree_same)
 443                 return;
 444         commit->object.flags |= TREESAME;
 445 }
 446
 447 static void insert_by_date_cached(struct commit *p, struct commit_list **head,
 448                     struct commit_list *cached_base, struct commit_list **cache)
 449 {
 450         struct commit_list *new_entry;
 451
 452         if (cached_base && p->date < cached_base->item->date)
 453                 new_entry = insert_by_date(p, &cached_base->next);
 454         else
 455                 new_entry = insert_by_date(p, head);
 456
 457         if (cache && (!*cache || p->date < (*cache)->item->date))
 458                 *cache = new_entry;
 459 }
 460
 461 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 462                     struct commit_list **list, struct commit_list **cache_ptr)
 463 {
 464         struct commit_list *parent = commit->parents;
 465         unsigned left_flag;
 466         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 467
 468         if (commit->object.flags & ADDED)
 469                 return 0;
 470         commit->object.flags |= ADDED;
 471
 472         /*
 473          * If the commit is uninteresting, don't try to
 474          * prune parents - we want the maximal uninteresting
 475          * set.
 476          *
 477          * Normally we haven't parsed the parent
 478          * yet, so we won't have a parent of a parent
 479          * here. However, it may turn out that we've
 480          * reached this commit some other way (where it
 481          * wasn't uninteresting), in which case we need
 482          * to mark its parents recursively too..
 483          */
 484         if (commit->object.flags & UNINTERESTING) {
 485                 while (parent) {
 486                         struct commit *p = parent->item;
 487                         parent = parent->next;
 488                         if (p)
 489                                 p->object.flags |= UNINTERESTING;
 490                         if (parse_commit(p) < 0)
 491                                 continue;
 492                         if (p->parents)
 493                                 mark_parents_uninteresting(p);
 494                         if (p->object.flags & SEEN)
 495                                 continue;
 496                         p->object.flags |= SEEN;
 497                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 498                 }
 499                 return 0;
 500         }
 501
 502         /*
 503          * Ok, the commit wasn't uninteresting. Try to
 504          * simplify the commit history and find the parent
 505          * that has no differences in the path set if one exists.
 506          */
 507         try_to_simplify_commit(revs, commit);
 508
 509         if (revs->no_walk)
 510                 return 0;
 511
 512         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 513
 514         for (parent = commit->parents; parent; parent = parent->next) {
 515                 struct commit *p = parent->item;
 516
 517                 if (parse_commit(p) < 0)
 518                         return -1;
 519                 if (revs->show_source && !p->util)
 520                         p->util = commit->util;
 521                 p->object.flags |= left_flag;
 522                 if (!(p->object.flags & SEEN)) {
 523                         p->object.flags |= SEEN;
 524                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 525                 }
 526                 if (revs->first_parent_only)
 527                         break;
 528         }
 529         return 0;
 530 }
 531
 532 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 533 {
 534         struct commit_list *p;
 535         int left_count = 0, right_count = 0;
 536         int left_first;
 537         struct patch_ids ids;
 538
 539         /* First count the commits on the left and on the right */
 540         for (p = list; p; p = p->next) {
 541                 struct commit *commit = p->item;
 542                 unsigned flags = commit->object.flags;
 543                 if (flags & BOUNDARY)
 544                         ;
 545                 else if (flags & SYMMETRIC_LEFT)
 546                         left_count++;
 547                 else
 548                         right_count++;
 549         }
 550
 551         if (!left_count || !right_count)
 552                 return;
 553
 554         left_first = left_count < right_count;
 555         init_patch_ids(&ids);
 556         if (revs->diffopt.nr_paths) {
 557                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 558                 ids.diffopts.paths = revs->diffopt.paths;
 559                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 560         }
 561
 562         /* Compute patch-ids for one side */
 563         for (p = list; p; p = p->next) {
 564                 struct commit *commit = p->item;
 565                 unsigned flags = commit->object.flags;
 566
 567                 if (flags & BOUNDARY)
 568                         continue;
 569                 /*
 570                  * If we have fewer left, left_first is set and we omit
 571                  * commits on the right branch in this loop.  If we have
 572                  * fewer right, we skip the left ones.
 573                  */
 574                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 575                         continue;
 576                 commit->util = add_commit_patch_id(commit, &ids);
 577         }
 578
 579         /* Check the other side */
 580         for (p = list; p; p = p->next) {
 581                 struct commit *commit = p->item;
 582                 struct patch_id *id;
 583                 unsigned flags = commit->object.flags;
 584
 585                 if (flags & BOUNDARY)
 586                         continue;
 587                 /*
 588                  * If we have fewer left, left_first is set and we omit
 589                  * commits on the left branch in this loop.
 590                  */
 591                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 592                         continue;
 593
 594                 /*
 595                  * Have we seen the same patch id?
 596                  */
 597                 id = has_commit_patch_id(commit, &ids);
 598                 if (!id)
 599                         continue;
 600                 id->seen = 1;
 601                 commit->object.flags |= SHOWN;
 602         }
 603
 604         /* Now check the original side for seen ones */
 605         for (p = list; p; p = p->next) {
 606                 struct commit *commit = p->item;
 607                 struct patch_id *ent;
 608
 609                 ent = commit->util;
 610                 if (!ent)
 611                         continue;
 612                 if (ent->seen)
 613                         commit->object.flags |= SHOWN;
 614                 commit->util = NULL;
 615         }
 616
 617         free_patch_ids(&ids);
 618 }
 619
 620 /* How many extra uninteresting commits we want to see.. */
 621 #define SLOP 5
 622
 623 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 624 {
 625         /*
 626          * No source list at all? We're definitely done..
 627          */
 628         if (!src)
 629                 return 0;
 630
 631         /*
 632          * Does the destination list contain entries with a date
 633          * before the source list? Definitely _not_ done.
 634          */
 635         if (date < src->item->date)
 636                 return SLOP;
 637
 638         /*
 639          * Does the source list still have interesting commits in
 640          * it? Definitely not done..
 641          */
 642         if (!everybody_uninteresting(src))
 643                 return SLOP;
 644
 645         /* Ok, we're closing in.. */
 646         return slop-1;
 647 }
 648
 649 static int limit_list(struct rev_info *revs)
 650 {
 651         int slop = SLOP;
 652         unsigned long date = ~0ul;
 653         struct commit_list *list = revs->commits;
 654         struct commit_list *newlist = NULL;
 655         struct commit_list **p = &newlist;
 656
 657         while (list) {
 658                 struct commit_list *entry = list;
 659                 struct commit *commit = list->item;
 660                 struct object *obj = &commit->object;
 661                 show_early_output_fn_t show;
 662
 663                 list = list->next;
 664                 free(entry);
 665
 666                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 667                         obj->flags |= UNINTERESTING;
 668                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 669                         return -1;
 670                 if (obj->flags & UNINTERESTING) {
 671                         mark_parents_uninteresting(commit);
 672                         if (revs->show_all)
 673                                 p = &commit_list_insert(commit, p)->next;
 674                         slop = still_interesting(list, date, slop);
 675                         if (slop)
 676                                 continue;
 677                         /* If showing all, add the whole pending list to the end */
 678                         if (revs->show_all)
 679                                 *p = list;
 680                         break;
 681                 }
 682                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 683                         continue;
 684                 date = commit->date;
 685                 p = &commit_list_insert(commit, p)->next;
 686
 687                 show = show_early_output;
 688                 if (!show)
 689                         continue;
 690
 691                 show(revs, newlist);
 692                 show_early_output = NULL;
 693         }
 694         if (revs->cherry_pick)
 695                 cherry_pick_list(newlist, revs);
 696
 697         revs->commits = newlist;
 698         return 0;
 699 }
 700
 701 struct all_refs_cb {
 702         int all_flags;
 703         int warned_bad_reflog;
 704         struct rev_info *all_revs;
 705         const char *name_for_errormsg;
 706 };
 707
 708 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 709 {
 710         struct all_refs_cb *cb = cb_data;
 711         struct object *object = get_reference(cb->all_revs, path, sha1,
 712                                               cb->all_flags);
 713         add_pending_object(cb->all_revs, object, path);
 714         return 0;
 715 }
 716
 717 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
 718         unsigned flags)
 719 {
 720         cb->all_revs = revs;
 721         cb->all_flags = flags;
 722 }
 723
 724 static void handle_refs(struct rev_info *revs, unsigned flags,
 725                 int (*for_each)(each_ref_fn, void *))
 726 {
 727         struct all_refs_cb cb;
 728         init_all_refs_cb(&cb, revs, flags);
 729         for_each(handle_one_ref, &cb);
 730 }
 731
 732 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 733 {
 734         struct all_refs_cb *cb = cb_data;
 735         if (!is_null_sha1(sha1)) {
 736                 struct object *o = parse_object(sha1);
 737                 if (o) {
 738                         o->flags |= cb->all_flags;
 739                         add_pending_object(cb->all_revs, o, "");
 740                 }
 741                 else if (!cb->warned_bad_reflog) {
 742                         warning("reflog of '%s' references pruned commits",
 743                                 cb->name_for_errormsg);
 744                         cb->warned_bad_reflog = 1;
 745                 }
 746         }
 747 }
 748
 749 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 750                 const char *email, unsigned long timestamp, int tz,
 751                 const char *message, void *cb_data)
 752 {
 753         handle_one_reflog_commit(osha1, cb_data);
 754         handle_one_reflog_commit(nsha1, cb_data);
 755         return 0;
 756 }
 757
 758 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 759 {
 760         struct all_refs_cb *cb = cb_data;
 761         cb->warned_bad_reflog = 0;
 762         cb->name_for_errormsg = path;
 763         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 764         return 0;
 765 }
 766
 767 static void handle_reflog(struct rev_info *revs, unsigned flags)
 768 {
 769         struct all_refs_cb cb;
 770         cb.all_revs = revs;
 771         cb.all_flags = flags;
 772         for_each_reflog(handle_one_reflog, &cb);
 773 }
 774
 775 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 776 {
 777         unsigned char sha1[20];
 778         struct object *it;
 779         struct commit *commit;
 780         struct commit_list *parents;
 781
 782         if (*arg == '^') {
 783                 flags ^= UNINTERESTING;
 784                 arg++;
 785         }
 786         if (get_sha1(arg, sha1))
 787                 return 0;
 788         while (1) {
 789                 it = get_reference(revs, arg, sha1, 0);
 790                 if (it->type != OBJ_TAG)
 791                         break;
 792                 if (!((struct tag*)it)->tagged)
 793                         return 0;
 794                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 795         }
 796         if (it->type != OBJ_COMMIT)
 797                 return 0;
 798         commit = (struct commit *)it;
 799         for (parents = commit->parents; parents; parents = parents->next) {
 800                 it = &parents->item->object;
 801                 it->flags |= flags;
 802                 add_pending_object(revs, it, arg);
 803         }
 804         return 1;
 805 }
 806
 807 void init_revisions(struct rev_info *revs, const char *prefix)
 808 {
 809         memset(revs, 0, sizeof(*revs));
 810
 811         revs->abbrev = DEFAULT_ABBREV;
 812         revs->ignore_merges = 1;
 813         revs->simplify_history = 1;
 814         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 815         DIFF_OPT_SET(&revs->pruning, QUICK);
 816         revs->pruning.add_remove = file_add_remove;
 817         revs->pruning.change = file_change;
 818         revs->lifo = 1;
 819         revs->dense = 1;
 820         revs->prefix = prefix;
 821         revs->max_age = -1;
 822         revs->min_age = -1;
 823         revs->skip_count = -1;
 824         revs->max_count = -1;
 825
 826         revs->commit_format = CMIT_FMT_DEFAULT;
 827
 828         revs->grep_filter.status_only = 1;
 829         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 830         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
 831         revs->grep_filter.regflags = REG_NEWLINE;
 832
 833         diff_setup(&revs->diffopt);
 834         if (prefix && !revs->diffopt.prefix) {
 835                 revs->diffopt.prefix = prefix;
 836                 revs->diffopt.prefix_length = strlen(prefix);
 837         }
 838 }
 839
 840 static void add_pending_commit_list(struct rev_info *revs,
 841                                     struct commit_list *commit_list,
 842                                     unsigned int flags)
 843 {
 844         while (commit_list) {
 845                 struct object *object = &commit_list->item->object;
 846                 object->flags |= flags;
 847                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 848                 commit_list = commit_list->next;
 849         }
 850 }
 851
 852 static void prepare_show_merge(struct rev_info *revs)
 853 {
 854         struct commit_list *bases;
 855         struct commit *head, *other;
 856         unsigned char sha1[20];
 857         const char **prune = NULL;
 858         int i, prune_num = 1; /* counting terminating NULL */
 859
 860         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 861                 die("--merge without HEAD?");
 862         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 863                 die("--merge without MERGE_HEAD?");
 864         add_pending_object(revs, &head->object, "HEAD");
 865         add_pending_object(revs, &other->object, "MERGE_HEAD");
 866         bases = get_merge_bases(head, other, 1);
 867         add_pending_commit_list(revs, bases, UNINTERESTING);
 868         free_commit_list(bases);
 869         head->object.flags |= SYMMETRIC_LEFT;
 870
 871         if (!active_nr)
 872                 read_cache();
 873         for (i = 0; i < active_nr; i++) {
 874                 struct cache_entry *ce = active_cache[i];
 875                 if (!ce_stage(ce))
 876                         continue;
 877                 if (ce_path_match(ce, revs->prune_data)) {
 878                         prune_num++;
 879                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 880                         prune[prune_num-2] = ce->name;
 881                         prune[prune_num-1] = NULL;
 882                 }
 883                 while ((i+1 < active_nr) &&
 884                        ce_same_name(ce, active_cache[i+1]))
 885                         i++;
 886         }
 887         revs->prune_data = prune;
 888         revs->limited = 1;
 889 }
 890
 891 int handle_revision_arg(const char *arg, struct rev_info *revs,
 892                         int flags,
 893                         int cant_be_filename)
 894 {
 895         unsigned mode;
 896         char *dotdot;
 897         struct object *object;
 898         unsigned char sha1[20];
 899         int local_flags;
 900
 901         dotdot = strstr(arg, "..");
 902         if (dotdot) {
 903                 unsigned char from_sha1[20];
 904                 const char *next = dotdot + 2;
 905                 const char *this = arg;
 906                 int symmetric = *next == '.';
 907                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 908
 909                 *dotdot = 0;
 910                 next += symmetric;
 911
 912                 if (!*next)
 913                         next = "HEAD";
 914                 if (dotdot == arg)
 915                         this = "HEAD";
 916                 if (!get_sha1(this, from_sha1) &&
 917                     !get_sha1(next, sha1)) {
 918                         struct commit *a, *b;
 919                         struct commit_list *exclude;
 920
 921                         a = lookup_commit_reference(from_sha1);
 922                         b = lookup_commit_reference(sha1);
 923                         if (!a || !b) {
 924                                 die(symmetric ?
 925                                     "Invalid symmetric difference expression %s...%s" :
 926                                     "Invalid revision range %s..%s",
 927                                     arg, next);
 928                         }
 929
 930                         if (!cant_be_filename) {
 931                                 *dotdot = '.';
 932                                 verify_non_filename(revs->prefix, arg);
 933                         }
 934
 935                         if (symmetric) {
 936                                 exclude = get_merge_bases(a, b, 1);
 937                                 add_pending_commit_list(revs, exclude,
 938                                                         flags_exclude);
 939                                 free_commit_list(exclude);
 940                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 941                         } else
 942                                 a->object.flags |= flags_exclude;
 943                         b->object.flags |= flags;
 944                         add_pending_object(revs, &a->object, this);
 945                         add_pending_object(revs, &b->object, next);
 946                         return 0;
 947                 }
 948                 *dotdot = '.';
 949         }
 950         dotdot = strstr(arg, "^@");
 951         if (dotdot && !dotdot[2]) {
 952                 *dotdot = 0;
 953                 if (add_parents_only(revs, arg, flags))
 954                         return 0;
 955                 *dotdot = '^';
 956         }
 957         dotdot = strstr(arg, "^!");
 958         if (dotdot && !dotdot[2]) {
 959                 *dotdot = 0;
 960                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 961                         *dotdot = '^';
 962         }
 963
 964         local_flags = 0;
 965         if (*arg == '^') {
 966                 local_flags = UNINTERESTING;
 967                 arg++;
 968         }
 969         if (get_sha1_with_mode(arg, sha1, &mode))
 970                 return -1;
 971         if (!cant_be_filename)
 972                 verify_non_filename(revs->prefix, arg);
 973         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 974         add_pending_object_with_mode(revs, object, arg, mode);
 975         return 0;
 976 }
 977
 978 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
 979 {
 980         const char **prune = *prune_data;
 981         int prune_nr;
 982         int prune_alloc;
 983
 984         /* count existing ones */
 985         if (!prune)
 986                 prune_nr = 0;
 987         else
 988                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
 989                         ;
 990         prune_alloc = prune_nr; /* not really, but we do not know */
 991
 992         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
 993                 int len = sb->len;
 994                 if (len && sb->buf[len - 1] == '\n')
 995                         sb->buf[--len] = '\0';
 996                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
 997                 prune[prune_nr++] = xstrdup(sb->buf);
 998         }
 999         if (prune) {
1000                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1001                 prune[prune_nr] = NULL;
1002         }
1003         *prune_data = prune;
1004 }
1005
1006 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1007 {
1008         struct strbuf sb;
1009         int seen_dashdash = 0;
1010
1011         strbuf_init(&sb, 1000);
1012         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1013                 int len = sb.len;
1014                 if (len && sb.buf[len - 1] == '\n')
1015                         sb.buf[--len] = '\0';
1016                 if (!len)
1017                         break;
1018                 if (sb.buf[0] == '-') {
1019                         if (len == 2 && sb.buf[1] == '-') {
1020                                 seen_dashdash = 1;
1021                                 break;
1022                         }
1023                         die("options not supported in --stdin mode");
1024                 }
1025                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1026                         die("bad revision '%s'", sb.buf);
1027         }
1028         if (seen_dashdash)
1029                 read_pathspec_from_stdin(revs, &sb, prune);
1030         strbuf_release(&sb);
1031 }
1032
1033 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1034 {
1035         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1036 }
1037
1038 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1039 {
1040         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1041 }
1042
1043 static void add_message_grep(struct rev_info *revs, const char *pattern)
1044 {
1045         add_grep(revs, pattern, GREP_PATTERN_BODY);
1046 }
1047
1048 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1049                                int *unkc, const char **unkv)
1050 {
1051         const char *arg = argv[0];
1052
1053         /* pseudo revision arguments */
1054         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1055             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1056             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1057             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1058             !strcmp(arg, "--bisect"))
1059         {
1060                 unkv[(*unkc)++] = arg;
1061                 return 1;
1062         }
1063
1064         if (!prefixcmp(arg, "--max-count=")) {
1065                 revs->max_count = atoi(arg + 12);
1066         } else if (!prefixcmp(arg, "--skip=")) {
1067                 revs->skip_count = atoi(arg + 7);
1068         } else if ((*arg == '-') && isdigit(arg[1])) {
1069         /* accept -<digit>, like traditional "head" */
1070                 revs->max_count = atoi(arg + 1);
1071         } else if (!strcmp(arg, "-n")) {
1072                 if (argc <= 1)
1073                         return error("-n requires an argument");
1074                 revs->max_count = atoi(argv[1]);
1075                 return 2;
1076         } else if (!prefixcmp(arg, "-n")) {
1077                 revs->max_count = atoi(arg + 2);
1078         } else if (!prefixcmp(arg, "--max-age=")) {
1079                 revs->max_age = atoi(arg + 10);
1080         } else if (!prefixcmp(arg, "--since=")) {
1081                 revs->max_age = approxidate(arg + 8);
1082         } else if (!prefixcmp(arg, "--after=")) {
1083                 revs->max_age = approxidate(arg + 8);
1084         } else if (!prefixcmp(arg, "--min-age=")) {
1085                 revs->min_age = atoi(arg + 10);
1086         } else if (!prefixcmp(arg, "--before=")) {
1087                 revs->min_age = approxidate(arg + 9);
1088         } else if (!prefixcmp(arg, "--until=")) {
1089                 revs->min_age = approxidate(arg + 8);
1090         } else if (!strcmp(arg, "--first-parent")) {
1091                 revs->first_parent_only = 1;
1092         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1093                 init_reflog_walk(&revs->reflog_info);
1094         } else if (!strcmp(arg, "--default")) {
1095                 if (argc <= 1)
1096                         return error("bad --default argument");
1097                 revs->def = argv[1];
1098                 return 2;
1099         } else if (!strcmp(arg, "--merge")) {
1100                 revs->show_merge = 1;
1101         } else if (!strcmp(arg, "--topo-order")) {
1102                 revs->lifo = 1;
1103                 revs->topo_order = 1;
1104         } else if (!strcmp(arg, "--simplify-merges")) {
1105                 revs->simplify_merges = 1;
1106                 revs->rewrite_parents = 1;
1107                 revs->simplify_history = 0;
1108                 revs->limited = 1;
1109         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1110                 revs->simplify_merges = 1;
1111                 revs->rewrite_parents = 1;
1112                 revs->simplify_history = 0;
1113                 revs->simplify_by_decoration = 1;
1114                 revs->limited = 1;
1115                 revs->prune = 1;
1116                 load_ref_decorations(DECORATE_SHORT_REFS);
1117         } else if (!strcmp(arg, "--date-order")) {
1118                 revs->lifo = 0;
1119                 revs->topo_order = 1;
1120         } else if (!prefixcmp(arg, "--early-output")) {
1121                 int count = 100;
1122                 switch (arg[14]) {
1123                 case '=':
1124                         count = atoi(arg+15);
1125                         /* Fallthrough */
1126                 case 0:
1127                         revs->topo_order = 1;
1128                        revs->early_output = count;
1129                 }
1130         } else if (!strcmp(arg, "--parents")) {
1131                 revs->rewrite_parents = 1;
1132                 revs->print_parents = 1;
1133         } else if (!strcmp(arg, "--dense")) {
1134                 revs->dense = 1;
1135         } else if (!strcmp(arg, "--sparse")) {
1136                 revs->dense = 0;
1137         } else if (!strcmp(arg, "--show-all")) {
1138                 revs->show_all = 1;
1139         } else if (!strcmp(arg, "--remove-empty")) {
1140                 revs->remove_empty_trees = 1;
1141         } else if (!strcmp(arg, "--merges")) {
1142                 revs->merges_only = 1;
1143         } else if (!strcmp(arg, "--no-merges")) {
1144                 revs->no_merges = 1;
1145         } else if (!strcmp(arg, "--boundary")) {
1146                 revs->boundary = 1;
1147         } else if (!strcmp(arg, "--left-right")) {
1148                 revs->left_right = 1;
1149         } else if (!strcmp(arg, "--cherry-pick")) {
1150                 revs->cherry_pick = 1;
1151                 revs->limited = 1;
1152         } else if (!strcmp(arg, "--objects")) {
1153                 revs->tag_objects = 1;
1154                 revs->tree_objects = 1;
1155                 revs->blob_objects = 1;
1156         } else if (!strcmp(arg, "--objects-edge")) {
1157                 revs->tag_objects = 1;
1158                 revs->tree_objects = 1;
1159                 revs->blob_objects = 1;
1160                 revs->edge_hint = 1;
1161         } else if (!strcmp(arg, "--unpacked")) {
1162                 revs->unpacked = 1;
1163         } else if (!prefixcmp(arg, "--unpacked=")) {
1164                 die("--unpacked=<packfile> no longer supported.");
1165         } else if (!strcmp(arg, "-r")) {
1166                 revs->diff = 1;
1167                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1168         } else if (!strcmp(arg, "-t")) {
1169                 revs->diff = 1;
1170                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1171                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1172         } else if (!strcmp(arg, "-m")) {
1173                 revs->ignore_merges = 0;
1174         } else if (!strcmp(arg, "-c")) {
1175                 revs->diff = 1;
1176                 revs->dense_combined_merges = 0;
1177                 revs->combine_merges = 1;
1178         } else if (!strcmp(arg, "--cc")) {
1179                 revs->diff = 1;
1180                 revs->dense_combined_merges = 1;
1181                 revs->combine_merges = 1;
1182         } else if (!strcmp(arg, "-v")) {
1183                 revs->verbose_header = 1;
1184         } else if (!strcmp(arg, "--pretty")) {
1185                 revs->verbose_header = 1;
1186                 revs->pretty_given = 1;
1187                 get_commit_format(arg+8, revs);
1188         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1189                 revs->verbose_header = 1;
1190                 revs->pretty_given = 1;
1191                 get_commit_format(arg+9, revs);
1192         } else if (!strcmp(arg, "--show-notes")) {
1193                 revs->show_notes = 1;
1194                 revs->show_notes_given = 1;
1195         } else if (!prefixcmp(arg, "--show-notes=")) {
1196                 struct strbuf buf = STRBUF_INIT;
1197                 revs->show_notes = 1;
1198                 revs->show_notes_given = 1;
1199                 if (!revs->notes_opt.extra_notes_refs)
1200                         revs->notes_opt.extra_notes_refs = xcalloc(1, sizeof(struct string_list));
1201                 if (!prefixcmp(arg+13, "refs/"))
1202                         /* happy */;
1203                 else if (!prefixcmp(arg+13, "notes/"))
1204                         strbuf_addstr(&buf, "refs/");
1205                 else
1206                         strbuf_addstr(&buf, "refs/notes/");
1207                 strbuf_addstr(&buf, arg+13);
1208                 string_list_append(strbuf_detach(&buf, NULL),
1209                                    revs->notes_opt.extra_notes_refs);
1210         } else if (!strcmp(arg, "--no-notes")) {
1211                 revs->show_notes = 0;
1212                 revs->show_notes_given = 1;
1213         } else if (!strcmp(arg, "--standard-notes")) {
1214                 revs->show_notes_given = 1;
1215                 revs->notes_opt.suppress_default_notes = 0;
1216         } else if (!strcmp(arg, "--no-standard-notes")) {
1217                 revs->notes_opt.suppress_default_notes = 1;
1218         } else if (!strcmp(arg, "--oneline")) {
1219                 revs->verbose_header = 1;
1220                 get_commit_format("oneline", revs);
1221                 revs->pretty_given = 1;
1222                 revs->abbrev_commit = 1;
1223         } else if (!strcmp(arg, "--graph")) {
1224                 revs->topo_order = 1;
1225                 revs->rewrite_parents = 1;
1226                 revs->graph = graph_init(revs);
1227         } else if (!strcmp(arg, "--root")) {
1228                 revs->show_root_diff = 1;
1229         } else if (!strcmp(arg, "--no-commit-id")) {
1230                 revs->no_commit_id = 1;
1231         } else if (!strcmp(arg, "--always")) {
1232                 revs->always_show_header = 1;
1233         } else if (!strcmp(arg, "--no-abbrev")) {
1234                 revs->abbrev = 0;
1235         } else if (!strcmp(arg, "--abbrev")) {
1236                 revs->abbrev = DEFAULT_ABBREV;
1237         } else if (!prefixcmp(arg, "--abbrev=")) {
1238                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1239                 if (revs->abbrev < MINIMUM_ABBREV)
1240                         revs->abbrev = MINIMUM_ABBREV;
1241                 else if (revs->abbrev > 40)
1242                         revs->abbrev = 40;
1243         } else if (!strcmp(arg, "--abbrev-commit")) {
1244                 revs->abbrev_commit = 1;
1245         } else if (!strcmp(arg, "--full-diff")) {
1246                 revs->diff = 1;
1247                 revs->full_diff = 1;
1248         } else if (!strcmp(arg, "--full-history")) {
1249                 revs->simplify_history = 0;
1250         } else if (!strcmp(arg, "--relative-date")) {
1251                 revs->date_mode = DATE_RELATIVE;
1252                 revs->date_mode_explicit = 1;
1253         } else if (!strncmp(arg, "--date=", 7)) {
1254                 revs->date_mode = parse_date_format(arg + 7);
1255                 revs->date_mode_explicit = 1;
1256         } else if (!strcmp(arg, "--log-size")) {
1257                 revs->show_log_size = 1;
1258         }
1259         /*
1260          * Grepping the commit log
1261          */
1262         else if (!prefixcmp(arg, "--author=")) {
1263                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1264         } else if (!prefixcmp(arg, "--committer=")) {
1265                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1266         } else if (!prefixcmp(arg, "--grep=")) {
1267                 add_message_grep(revs, arg+7);
1268         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1269                 revs->grep_filter.regflags |= REG_EXTENDED;
1270         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1271                 revs->grep_filter.regflags |= REG_ICASE;
1272         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1273                 revs->grep_filter.fixed = 1;
1274         } else if (!strcmp(arg, "--all-match")) {
1275                 revs->grep_filter.all_match = 1;
1276         } else if (!prefixcmp(arg, "--encoding=")) {
1277                 arg += 11;
1278                 if (strcmp(arg, "none"))
1279                         git_log_output_encoding = xstrdup(arg);
1280                 else
1281                         git_log_output_encoding = "";
1282         } else if (!strcmp(arg, "--reverse")) {
1283                 revs->reverse ^= 1;
1284         } else if (!strcmp(arg, "--children")) {
1285                 revs->children.name = "children";
1286                 revs->limited = 1;
1287         } else {
1288                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1289                 if (!opts)
1290                         unkv[(*unkc)++] = arg;
1291                 return opts;
1292         }
1293
1294         return 1;
1295 }
1296
1297 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1298                         const struct option *options,
1299                         const char * const usagestr[])
1300 {
1301         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1302                                     &ctx->cpidx, ctx->out);
1303         if (n <= 0) {
1304                 error("unknown option `%s'", ctx->argv[0]);
1305                 usage_with_options(usagestr, options);
1306         }
1307         ctx->argv += n;
1308         ctx->argc -= n;
1309 }
1310
1311 static int for_each_bad_bisect_ref(each_ref_fn fn, void *cb_data)
1312 {
1313         return for_each_ref_in("refs/bisect/bad", fn, cb_data);
1314 }
1315
1316 static int for_each_good_bisect_ref(each_ref_fn fn, void *cb_data)
1317 {
1318         return for_each_ref_in("refs/bisect/good", fn, cb_data);
1319 }
1320
1321 static void append_prune_data(const char ***prune_data, const char **av)
1322 {
1323         const char **prune = *prune_data;
1324         int prune_nr;
1325         int prune_alloc;
1326
1327         if (!prune) {
1328                 *prune_data = av;
1329                 return;
1330         }
1331
1332         /* count existing ones */
1333         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1334                 ;
1335         prune_alloc = prune_nr; /* not really, but we do not know */
1336
1337         while (*av) {
1338                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1339                 prune[prune_nr++] = *av;
1340                 av++;
1341         }
1342         if (prune) {
1343                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1344                 prune[prune_nr] = NULL;
1345         }
1346         *prune_data = prune;
1347 }
1348
1349 /*
1350  * Parse revision information, filling in the "rev_info" structure,
1351  * and removing the used arguments from the argument list.
1352  *
1353  * Returns the number of arguments left that weren't recognized
1354  * (which are also moved to the head of the argument list)
1355  */
1356 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1357 {
1358         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1359         const char **prune_data = NULL;
1360
1361         /* First, search for "--" */
1362         seen_dashdash = 0;
1363         for (i = 1; i < argc; i++) {
1364                 const char *arg = argv[i];
1365                 if (strcmp(arg, "--"))
1366                         continue;
1367                 argv[i] = NULL;
1368                 argc = i;
1369                 if (argv[i + 1])
1370                         prune_data = argv + i + 1;
1371                 seen_dashdash = 1;
1372                 break;
1373         }
1374
1375         /* Second, deal with arguments and options */
1376         flags = 0;
1377         read_from_stdin = 0;
1378         for (left = i = 1; i < argc; i++) {
1379                 const char *arg = argv[i];
1380                 if (*arg == '-') {
1381                         int opts;
1382
1383                         if (!strcmp(arg, "--all")) {
1384                                 handle_refs(revs, flags, for_each_ref);
1385                                 handle_refs(revs, flags, head_ref);
1386                                 continue;
1387                         }
1388                         if (!strcmp(arg, "--branches")) {
1389                                 handle_refs(revs, flags, for_each_branch_ref);
1390                                 continue;
1391                         }
1392                         if (!strcmp(arg, "--bisect")) {
1393                                 handle_refs(revs, flags, for_each_bad_bisect_ref);
1394                                 handle_refs(revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1395                                 revs->bisect = 1;
1396                                 continue;
1397                         }
1398                         if (!strcmp(arg, "--tags")) {
1399                                 handle_refs(revs, flags, for_each_tag_ref);
1400                                 continue;
1401                         }
1402                         if (!strcmp(arg, "--remotes")) {
1403                                 handle_refs(revs, flags, for_each_remote_ref);
1404                                 continue;
1405                         }
1406                         if (!prefixcmp(arg, "--glob=")) {
1407                                 struct all_refs_cb cb;
1408                                 init_all_refs_cb(&cb, revs, flags);
1409                                 for_each_glob_ref(handle_one_ref, arg + 7, &cb);
1410                                 continue;
1411                         }
1412                         if (!prefixcmp(arg, "--branches=")) {
1413                                 struct all_refs_cb cb;
1414                                 init_all_refs_cb(&cb, revs, flags);
1415                                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1416                                 continue;
1417                         }
1418                         if (!prefixcmp(arg, "--tags=")) {
1419                                 struct all_refs_cb cb;
1420                                 init_all_refs_cb(&cb, revs, flags);
1421                                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1422                                 continue;
1423                         }
1424                         if (!prefixcmp(arg, "--remotes=")) {
1425                                 struct all_refs_cb cb;
1426                                 init_all_refs_cb(&cb, revs, flags);
1427                                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1428                                 continue;
1429                         }
1430                         if (!strcmp(arg, "--reflog")) {
1431                                 handle_reflog(revs, flags);
1432                                 continue;
1433                         }
1434                         if (!strcmp(arg, "--not")) {
1435                                 flags ^= UNINTERESTING;
1436                                 continue;
1437                         }
1438                         if (!strcmp(arg, "--no-walk")) {
1439                                 revs->no_walk = 1;
1440                                 continue;
1441                         }
1442                         if (!strcmp(arg, "--do-walk")) {
1443                                 revs->no_walk = 0;
1444                                 continue;
1445                         }
1446                         if (!strcmp(arg, "--stdin")) {
1447                                 if (revs->disable_stdin) {
1448                                         argv[left++] = arg;
1449                                         continue;
1450                                 }
1451                                 if (read_from_stdin++)
1452                                         die("--stdin given twice?");
1453                                 read_revisions_from_stdin(revs, &prune_data);
1454                                 continue;
1455                         }
1456
1457                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1458                         if (opts > 0) {
1459                                 i += opts - 1;
1460                                 continue;
1461                         }
1462                         if (opts < 0)
1463                                 exit(128);
1464                         continue;
1465                 }
1466
1467                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1468                         int j;
1469                         if (seen_dashdash || *arg == '^')
1470                                 die("bad revision '%s'", arg);
1471
1472                         /* If we didn't have a "--":
1473                          * (1) all filenames must exist;
1474                          * (2) all rev-args must not be interpretable
1475                          *     as a valid filename.
1476                          * but the latter we have checked in the main loop.
1477                          */
1478                         for (j = i; j < argc; j++)
1479                                 verify_filename(revs->prefix, argv[j]);
1480
1481                         append_prune_data(&prune_data, argv + i);
1482                         break;
1483                 }
1484                 else
1485                         got_rev_arg = 1;
1486         }
1487
1488         if (prune_data)
1489                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1490
1491         if (revs->def == NULL)
1492                 revs->def = opt ? opt->def : NULL;
1493         if (opt && opt->tweak)
1494                 opt->tweak(revs, opt);
1495         if (revs->show_merge)
1496                 prepare_show_merge(revs);
1497         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1498                 unsigned char sha1[20];
1499                 struct object *object;
1500                 unsigned mode;
1501                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1502                         die("bad default revision '%s'", revs->def);
1503                 object = get_reference(revs, revs->def, sha1, 0);
1504                 add_pending_object_with_mode(revs, object, revs->def, mode);
1505         }
1506
1507         /* Did the user ask for any diff output? Run the diff! */
1508         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1509                 revs->diff = 1;
1510
1511         /* Pickaxe, diff-filter and rename following need diffs */
1512         if (revs->diffopt.pickaxe ||
1513             revs->diffopt.filter ||
1514             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1515                 revs->diff = 1;
1516
1517         if (revs->topo_order)
1518                 revs->limited = 1;
1519
1520         if (revs->prune_data) {
1521                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1522                 /* Can't prune commits with rename following: the paths change.. */
1523                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1524                         revs->prune = 1;
1525                 if (!revs->full_diff)
1526                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1527         }
1528         if (revs->combine_merges)
1529                 revs->ignore_merges = 0;
1530         revs->diffopt.abbrev = revs->abbrev;
1531         if (diff_setup_done(&revs->diffopt) < 0)
1532                 die("diff_setup_done failed");
1533
1534         compile_grep_patterns(&revs->grep_filter);
1535
1536         if (revs->reverse && revs->reflog_info)
1537                 die("cannot combine --reverse with --walk-reflogs");
1538         if (revs->rewrite_parents && revs->children.name)
1539                 die("cannot combine --parents and --children");
1540
1541         /*
1542          * Limitations on the graph functionality
1543          */
1544         if (revs->reverse && revs->graph)
1545                 die("cannot combine --reverse with --graph");
1546
1547         if (revs->reflog_info && revs->graph)
1548                 die("cannot combine --walk-reflogs with --graph");
1549
1550         return left;
1551 }
1552
1553 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1554 {
1555         struct commit_list *l = xcalloc(1, sizeof(*l));
1556
1557         l->item = child;
1558         l->next = add_decoration(&revs->children, &parent->object, l);
1559 }
1560
1561 static int remove_duplicate_parents(struct commit *commit)
1562 {
1563         struct commit_list **pp, *p;
1564         int surviving_parents;
1565
1566         /* Examine existing parents while marking ones we have seen... */
1567         pp = &commit->parents;
1568         while ((p = *pp) != NULL) {
1569                 struct commit *parent = p->item;
1570                 if (parent->object.flags & TMP_MARK) {
1571                         *pp = p->next;
1572                         continue;
1573                 }
1574                 parent->object.flags |= TMP_MARK;
1575                 pp = &p->next;
1576         }
1577         /* count them while clearing the temporary mark */
1578         surviving_parents = 0;
1579         for (p = commit->parents; p; p = p->next) {
1580                 p->item->object.flags &= ~TMP_MARK;
1581                 surviving_parents++;
1582         }
1583         return surviving_parents;
1584 }
1585
1586 struct merge_simplify_state {
1587         struct commit *simplified;
1588 };
1589
1590 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1591 {
1592         struct merge_simplify_state *st;
1593
1594         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1595         if (!st) {
1596                 st = xcalloc(1, sizeof(*st));
1597                 add_decoration(&revs->merge_simplification, &commit->object, st);
1598         }
1599         return st;
1600 }
1601
1602 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1603 {
1604         struct commit_list *p;
1605         struct merge_simplify_state *st, *pst;
1606         int cnt;
1607
1608         st = locate_simplify_state(revs, commit);
1609
1610         /*
1611          * Have we handled this one?
1612          */
1613         if (st->simplified)
1614                 return tail;
1615
1616         /*
1617          * An UNINTERESTING commit simplifies to itself, so does a
1618          * root commit.  We do not rewrite parents of such commit
1619          * anyway.
1620          */
1621         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1622                 st->simplified = commit;
1623                 return tail;
1624         }
1625
1626         /*
1627          * Do we know what commit all of our parents should be rewritten to?
1628          * Otherwise we are not ready to rewrite this one yet.
1629          */
1630         for (cnt = 0, p = commit->parents; p; p = p->next) {
1631                 pst = locate_simplify_state(revs, p->item);
1632                 if (!pst->simplified) {
1633                         tail = &commit_list_insert(p->item, tail)->next;
1634                         cnt++;
1635                 }
1636         }
1637         if (cnt) {
1638                 tail = &commit_list_insert(commit, tail)->next;
1639                 return tail;
1640         }
1641
1642         /*
1643          * Rewrite our list of parents.
1644          */
1645         for (p = commit->parents; p; p = p->next) {
1646                 pst = locate_simplify_state(revs, p->item);
1647                 p->item = pst->simplified;
1648         }
1649         cnt = remove_duplicate_parents(commit);
1650
1651         /*
1652          * It is possible that we are a merge and one side branch
1653          * does not have any commit that touches the given paths;
1654          * in such a case, the immediate parents will be rewritten
1655          * to different commits.
1656          *
1657          *      o----X          X: the commit we are looking at;
1658          *     /    /           o: a commit that touches the paths;
1659          * ---o----'
1660          *
1661          * Further reduce the parents by removing redundant parents.
1662          */
1663         if (1 < cnt) {
1664                 struct commit_list *h = reduce_heads(commit->parents);
1665                 cnt = commit_list_count(h);
1666                 free_commit_list(commit->parents);
1667                 commit->parents = h;
1668         }
1669
1670         /*
1671          * A commit simplifies to itself if it is a root, if it is
1672          * UNINTERESTING, if it touches the given paths, or if it is a
1673          * merge and its parents simplifies to more than one commits
1674          * (the first two cases are already handled at the beginning of
1675          * this function).
1676          *
1677          * Otherwise, it simplifies to what its sole parent simplifies to.
1678          */
1679         if (!cnt ||
1680             (commit->object.flags & UNINTERESTING) ||
1681             !(commit->object.flags & TREESAME) ||
1682             (1 < cnt))
1683                 st->simplified = commit;
1684         else {
1685                 pst = locate_simplify_state(revs, commit->parents->item);
1686                 st->simplified = pst->simplified;
1687         }
1688         return tail;
1689 }
1690
1691 static void simplify_merges(struct rev_info *revs)
1692 {
1693         struct commit_list *list;
1694         struct commit_list *yet_to_do, **tail;
1695
1696         if (!revs->topo_order)
1697                 sort_in_topological_order(&revs->commits, revs->lifo);
1698         if (!revs->prune)
1699                 return;
1700
1701         /* feed the list reversed */
1702         yet_to_do = NULL;
1703         for (list = revs->commits; list; list = list->next)
1704                 commit_list_insert(list->item, &yet_to_do);
1705         while (yet_to_do) {
1706                 list = yet_to_do;
1707                 yet_to_do = NULL;
1708                 tail = &yet_to_do;
1709                 while (list) {
1710                         struct commit *commit = list->item;
1711                         struct commit_list *next = list->next;
1712                         free(list);
1713                         list = next;
1714                         tail = simplify_one(revs, commit, tail);
1715                 }
1716         }
1717
1718         /* clean up the result, removing the simplified ones */
1719         list = revs->commits;
1720         revs->commits = NULL;
1721         tail = &revs->commits;
1722         while (list) {
1723                 struct commit *commit = list->item;
1724                 struct commit_list *next = list->next;
1725                 struct merge_simplify_state *st;
1726                 free(list);
1727                 list = next;
1728                 st = locate_simplify_state(revs, commit);
1729                 if (st->simplified == commit)
1730                         tail = &commit_list_insert(commit, tail)->next;
1731         }
1732 }
1733
1734 static void set_children(struct rev_info *revs)
1735 {
1736         struct commit_list *l;
1737         for (l = revs->commits; l; l = l->next) {
1738                 struct commit *commit = l->item;
1739                 struct commit_list *p;
1740
1741                 for (p = commit->parents; p; p = p->next)
1742                         add_child(revs, p->item, commit);
1743         }
1744 }
1745
1746 int prepare_revision_walk(struct rev_info *revs)
1747 {
1748         int nr = revs->pending.nr;
1749         struct object_array_entry *e, *list;
1750
1751         e = list = revs->pending.objects;
1752         revs->pending.nr = 0;
1753         revs->pending.alloc = 0;
1754         revs->pending.objects = NULL;
1755         while (--nr >= 0) {
1756                 struct commit *commit = handle_commit(revs, e->item, e->name);
1757                 if (commit) {
1758                         if (!(commit->object.flags & SEEN)) {
1759                                 commit->object.flags |= SEEN;
1760                                 insert_by_date(commit, &revs->commits);
1761                         }
1762                 }
1763                 e++;
1764         }
1765         free(list);
1766
1767         if (revs->no_walk)
1768                 return 0;
1769         if (revs->limited)
1770                 if (limit_list(revs) < 0)
1771                         return -1;
1772         if (revs->topo_order)
1773                 sort_in_topological_order(&revs->commits, revs->lifo);
1774         if (revs->simplify_merges)
1775                 simplify_merges(revs);
1776         if (revs->children.name)
1777                 set_children(revs);
1778         return 0;
1779 }
1780
1781 enum rewrite_result {
1782         rewrite_one_ok,
1783         rewrite_one_noparents,
1784         rewrite_one_error
1785 };
1786
1787 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1788 {
1789         struct commit_list *cache = NULL;
1790
1791         for (;;) {
1792                 struct commit *p = *pp;
1793                 if (!revs->limited)
1794                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1795                                 return rewrite_one_error;
1796                 if (p->parents && p->parents->next)
1797                         return rewrite_one_ok;
1798                 if (p->object.flags & UNINTERESTING)
1799                         return rewrite_one_ok;
1800                 if (!(p->object.flags & TREESAME))
1801                         return rewrite_one_ok;
1802                 if (!p->parents)
1803                         return rewrite_one_noparents;
1804                 *pp = p->parents->item;
1805         }
1806 }
1807
1808 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1809 {
1810         struct commit_list **pp = &commit->parents;
1811         while (*pp) {
1812                 struct commit_list *parent = *pp;
1813                 switch (rewrite_one(revs, &parent->item)) {
1814                 case rewrite_one_ok:
1815                         break;
1816                 case rewrite_one_noparents:
1817                         *pp = parent->next;
1818                         continue;
1819                 case rewrite_one_error:
1820                         return -1;
1821                 }
1822                 pp = &parent->next;
1823         }
1824         remove_duplicate_parents(commit);
1825         return 0;
1826 }
1827
1828 static int commit_match(struct commit *commit, struct rev_info *opt)
1829 {
1830         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
1831                 return 1;
1832         return grep_buffer(&opt->grep_filter,
1833                            NULL, /* we say nothing, not even filename */
1834                            commit->buffer, strlen(commit->buffer));
1835 }
1836
1837 static inline int want_ancestry(struct rev_info *revs)
1838 {
1839         return (revs->rewrite_parents || revs->children.name);
1840 }
1841
1842 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1843 {
1844         if (commit->object.flags & SHOWN)
1845                 return commit_ignore;
1846         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1847                 return commit_ignore;
1848         if (revs->show_all)
1849                 return commit_show;
1850         if (commit->object.flags & UNINTERESTING)
1851                 return commit_ignore;
1852         if (revs->min_age != -1 && (commit->date > revs->min_age))
1853                 return commit_ignore;
1854         if (revs->no_merges && commit->parents && commit->parents->next)
1855                 return commit_ignore;
1856         if (revs->merges_only && !(commit->parents && commit->parents->next))
1857                 return commit_ignore;
1858         if (!commit_match(commit, revs))
1859                 return commit_ignore;
1860         if (revs->prune && revs->dense) {
1861                 /* Commit without changes? */
1862                 if (commit->object.flags & TREESAME) {
1863                         /* drop merges unless we want parenthood */
1864                         if (!want_ancestry(revs))
1865                                 return commit_ignore;
1866                         /* non-merge - always ignore it */
1867                         if (!commit->parents || !commit->parents->next)
1868                                 return commit_ignore;
1869                 }
1870         }
1871         return commit_show;
1872 }
1873
1874 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1875 {
1876         enum commit_action action = get_commit_action(revs, commit);
1877
1878         if (action == commit_show &&
1879             !revs->show_all &&
1880             revs->prune && revs->dense && want_ancestry(revs)) {
1881                 if (rewrite_parents(revs, commit) < 0)
1882                         return commit_error;
1883         }
1884         return action;
1885 }
1886
1887 static struct commit *get_revision_1(struct rev_info *revs)
1888 {
1889         if (!revs->commits)
1890                 return NULL;
1891
1892         do {
1893                 struct commit_list *entry = revs->commits;
1894                 struct commit *commit = entry->item;
1895
1896                 revs->commits = entry->next;
1897                 free(entry);
1898
1899                 if (revs->reflog_info)
1900                         fake_reflog_parent(revs->reflog_info, commit);
1901
1902                 /*
1903                  * If we haven't done the list limiting, we need to look at
1904                  * the parents here. We also need to do the date-based limiting
1905                  * that we'd otherwise have done in limit_list().
1906                  */
1907                 if (!revs->limited) {
1908                         if (revs->max_age != -1 &&
1909                             (commit->date < revs->max_age))
1910                                 continue;
1911                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1912                                 die("Failed to traverse parents of commit %s",
1913                                     sha1_to_hex(commit->object.sha1));
1914                 }
1915
1916                 switch (simplify_commit(revs, commit)) {
1917                 case commit_ignore:
1918                         continue;
1919                 case commit_error:
1920                         die("Failed to simplify parents of commit %s",
1921                             sha1_to_hex(commit->object.sha1));
1922                 default:
1923                         return commit;
1924                 }
1925         } while (revs->commits);
1926         return NULL;
1927 }
1928
1929 static void gc_boundary(struct object_array *array)
1930 {
1931         unsigned nr = array->nr;
1932         unsigned alloc = array->alloc;
1933         struct object_array_entry *objects = array->objects;
1934
1935         if (alloc <= nr) {
1936                 unsigned i, j;
1937                 for (i = j = 0; i < nr; i++) {
1938                         if (objects[i].item->flags & SHOWN)
1939                                 continue;
1940                         if (i != j)
1941                                 objects[j] = objects[i];
1942                         j++;
1943                 }
1944                 for (i = j; i < nr; i++)
1945                         objects[i].item = NULL;
1946                 array->nr = j;
1947         }
1948 }
1949
1950 static void create_boundary_commit_list(struct rev_info *revs)
1951 {
1952         unsigned i;
1953         struct commit *c;
1954         struct object_array *array = &revs->boundary_commits;
1955         struct object_array_entry *objects = array->objects;
1956
1957         /*
1958          * If revs->commits is non-NULL at this point, an error occurred in
1959          * get_revision_1().  Ignore the error and continue printing the
1960          * boundary commits anyway.  (This is what the code has always
1961          * done.)
1962          */
1963         if (revs->commits) {
1964                 free_commit_list(revs->commits);
1965                 revs->commits = NULL;
1966         }
1967
1968         /*
1969          * Put all of the actual boundary commits from revs->boundary_commits
1970          * into revs->commits
1971          */
1972         for (i = 0; i < array->nr; i++) {
1973                 c = (struct commit *)(objects[i].item);
1974                 if (!c)
1975                         continue;
1976                 if (!(c->object.flags & CHILD_SHOWN))
1977                         continue;
1978                 if (c->object.flags & (SHOWN | BOUNDARY))
1979                         continue;
1980                 c->object.flags |= BOUNDARY;
1981                 commit_list_insert(c, &revs->commits);
1982         }
1983
1984         /*
1985          * If revs->topo_order is set, sort the boundary commits
1986          * in topological order
1987          */
1988         sort_in_topological_order(&revs->commits, revs->lifo);
1989 }
1990
1991 static struct commit *get_revision_internal(struct rev_info *revs)
1992 {
1993         struct commit *c = NULL;
1994         struct commit_list *l;
1995
1996         if (revs->boundary == 2) {
1997                 /*
1998                  * All of the normal commits have already been returned,
1999                  * and we are now returning boundary commits.
2000                  * create_boundary_commit_list() has populated
2001                  * revs->commits with the remaining commits to return.
2002                  */
2003                 c = pop_commit(&revs->commits);
2004                 if (c)
2005                         c->object.flags |= SHOWN;
2006                 return c;
2007         }
2008
2009         /*
2010          * Now pick up what they want to give us
2011          */
2012         c = get_revision_1(revs);
2013         if (c) {
2014                 while (0 < revs->skip_count) {
2015                         revs->skip_count--;
2016                         c = get_revision_1(revs);
2017                         if (!c)
2018                                 break;
2019                 }
2020         }
2021
2022         /*
2023          * Check the max_count.
2024          */
2025         switch (revs->max_count) {
2026         case -1:
2027                 break;
2028         case 0:
2029                 c = NULL;
2030                 break;
2031         default:
2032                 revs->max_count--;
2033         }
2034
2035         if (c)
2036                 c->object.flags |= SHOWN;
2037
2038         if (!revs->boundary) {
2039                 return c;
2040         }
2041
2042         if (!c) {
2043                 /*
2044                  * get_revision_1() runs out the commits, and
2045                  * we are done computing the boundaries.
2046                  * switch to boundary commits output mode.
2047                  */
2048                 revs->boundary = 2;
2049
2050                 /*
2051                  * Update revs->commits to contain the list of
2052                  * boundary commits.
2053                  */
2054                 create_boundary_commit_list(revs);
2055
2056                 return get_revision_internal(revs);
2057         }
2058
2059         /*
2060          * boundary commits are the commits that are parents of the
2061          * ones we got from get_revision_1() but they themselves are
2062          * not returned from get_revision_1().  Before returning
2063          * 'c', we need to mark its parents that they could be boundaries.
2064          */
2065
2066         for (l = c->parents; l; l = l->next) {
2067                 struct object *p;
2068                 p = &(l->item->object);
2069                 if (p->flags & (CHILD_SHOWN | SHOWN))
2070                         continue;
2071                 p->flags |= CHILD_SHOWN;
2072                 gc_boundary(&revs->boundary_commits);
2073                 add_object_array(p, NULL, &revs->boundary_commits);
2074         }
2075
2076         return c;
2077 }
2078
2079 struct commit *get_revision(struct rev_info *revs)
2080 {
2081         struct commit *c;
2082         struct commit_list *reversed;
2083
2084         if (revs->reverse) {
2085                 reversed = NULL;
2086                 while ((c = get_revision_internal(revs))) {
2087                         commit_list_insert(c, &reversed);
2088                 }
2089                 revs->commits = reversed;
2090                 revs->reverse = 0;
2091                 revs->reverse_output_stage = 1;
2092         }
2093
2094         if (revs->reverse_output_stage)
2095                 return pop_commit(&revs->commits);
2096
2097         c = get_revision_internal(revs);
2098         if (c && revs->graph)
2099                 graph_update(revs->graph, c);
2100         return c;
2101 }