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