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 #include "line-log.h"
  17 #include "mailmap.h"
  18 #include "commit-slab.h"
  19 #include "dir.h"
  20 #include "cache-tree.h"
  21
  22 volatile show_early_output_fn_t show_early_output;
  23
  24 void show_object_with_name(FILE *out, struct object *obj, const char *name)
  25 {
  26         const char *p;
  27
  28         fprintf(out, "%s ", sha1_to_hex(obj->sha1));
  29         for (p = name; *p && *p != '\n'; p++)
  30                 fputc(*p, out);
  31         fputc('\n', out);
  32 }
  33
  34 static void mark_blob_uninteresting(struct blob *blob)
  35 {
  36         if (!blob)
  37                 return;
  38         if (blob->object.flags & UNINTERESTING)
  39                 return;
  40         blob->object.flags |= UNINTERESTING;
  41 }
  42
  43 static void mark_tree_contents_uninteresting(struct tree *tree)
  44 {
  45         struct tree_desc desc;
  46         struct name_entry entry;
  47         struct object *obj = &tree->object;
  48
  49         if (!has_sha1_file(obj->sha1))
  50                 return;
  51         if (parse_tree(tree) < 0)
  52                 die("bad tree %s", sha1_to_hex(obj->sha1));
  53
  54         init_tree_desc(&desc, tree->buffer, tree->size);
  55         while (tree_entry(&desc, &entry)) {
  56                 switch (object_type(entry.mode)) {
  57                 case OBJ_TREE:
  58                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  59                         break;
  60                 case OBJ_BLOB:
  61                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  62                         break;
  63                 default:
  64                         /* Subproject commit - not in this repository */
  65                         break;
  66                 }
  67         }
  68
  69         /*
  70          * We don't care about the tree any more
  71          * after it has been marked uninteresting.
  72          */
  73         free_tree_buffer(tree);
  74 }
  75
  76 void mark_tree_uninteresting(struct tree *tree)
  77 {
  78         struct object *obj = &tree->object;
  79
  80         if (!tree)
  81                 return;
  82         if (obj->flags & UNINTERESTING)
  83                 return;
  84         obj->flags |= UNINTERESTING;
  85         mark_tree_contents_uninteresting(tree);
  86 }
  87
  88 void mark_parents_uninteresting(struct commit *commit)
  89 {
  90         struct commit_list *parents = NULL, *l;
  91
  92         for (l = commit->parents; l; l = l->next)
  93                 commit_list_insert(l->item, &parents);
  94
  95         while (parents) {
  96                 struct commit *commit = parents->item;
  97                 l = parents;
  98                 parents = parents->next;
  99                 free(l);
 100
 101                 while (commit) {
 102                         /*
 103                          * A missing commit is ok iff its parent is marked
 104                          * uninteresting.
 105                          *
 106                          * We just mark such a thing parsed, so that when
 107                          * it is popped next time around, we won't be trying
 108                          * to parse it and get an error.
 109                          */
 110                         if (!has_sha1_file(commit->object.sha1))
 111                                 commit->object.parsed = 1;
 112
 113                         if (commit->object.flags & UNINTERESTING)
 114                                 break;
 115
 116                         commit->object.flags |= UNINTERESTING;
 117
 118                         /*
 119                          * Normally we haven't parsed the parent
 120                          * yet, so we won't have a parent of a parent
 121                          * here. However, it may turn out that we've
 122                          * reached this commit some other way (where it
 123                          * wasn't uninteresting), in which case we need
 124                          * to mark its parents recursively too..
 125                          */
 126                         if (!commit->parents)
 127                                 break;
 128
 129                         for (l = commit->parents->next; l; l = l->next)
 130                                 commit_list_insert(l->item, &parents);
 131                         commit = commit->parents->item;
 132                 }
 133         }
 134 }
 135
 136 static void add_pending_object_with_path(struct rev_info *revs,
 137                                          struct object *obj,
 138                                          const char *name, unsigned mode,
 139                                          const char *path)
 140 {
 141         if (!obj)
 142                 return;
 143         if (revs->no_walk && (obj->flags & UNINTERESTING))
 144                 revs->no_walk = 0;
 145         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 146                 struct strbuf buf = STRBUF_INIT;
 147                 int len = interpret_branch_name(name, 0, &buf);
 148                 int st;
 149
 150                 if (0 < len && name[len] && buf.len)
 151                         strbuf_addstr(&buf, name + len);
 152                 st = add_reflog_for_walk(revs->reflog_info,
 153                                          (struct commit *)obj,
 154                                          buf.buf[0] ? buf.buf: name);
 155                 strbuf_release(&buf);
 156                 if (st)
 157                         return;
 158         }
 159         add_object_array_with_path(obj, name, &revs->pending, mode, path);
 160 }
 161
 162 static void add_pending_object_with_mode(struct rev_info *revs,
 163                                          struct object *obj,
 164                                          const char *name, unsigned mode)
 165 {
 166         add_pending_object_with_path(revs, obj, name, mode, NULL);
 167 }
 168
 169 void add_pending_object(struct rev_info *revs,
 170                         struct object *obj, const char *name)
 171 {
 172         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 173 }
 174
 175 void add_head_to_pending(struct rev_info *revs)
 176 {
 177         unsigned char sha1[20];
 178         struct object *obj;
 179         if (get_sha1("HEAD", sha1))
 180                 return;
 181         obj = parse_object(sha1);
 182         if (!obj)
 183                 return;
 184         add_pending_object(revs, obj, "HEAD");
 185 }
 186
 187 static struct object *get_reference(struct rev_info *revs, const char *name,
 188                                     const unsigned char *sha1,
 189                                     unsigned int flags)
 190 {
 191         struct object *object;
 192
 193         object = parse_object(sha1);
 194         if (!object) {
 195                 if (revs->ignore_missing)
 196                         return object;
 197                 die("bad object %s", name);
 198         }
 199         object->flags |= flags;
 200         return object;
 201 }
 202
 203 void add_pending_sha1(struct rev_info *revs, const char *name,
 204                       const unsigned char *sha1, unsigned int flags)
 205 {
 206         struct object *object = get_reference(revs, name, sha1, flags);
 207         add_pending_object(revs, object, name);
 208 }
 209
 210 static struct commit *handle_commit(struct rev_info *revs,
 211                                     struct object_array_entry *entry)
 212 {
 213         struct object *object = entry->item;
 214         const char *name = entry->name;
 215         const char *path = entry->path;
 216         unsigned int mode = entry->mode;
 217         unsigned long flags = object->flags;
 218
 219         /*
 220          * Tag object? Look what it points to..
 221          */
 222         while (object->type == OBJ_TAG) {
 223                 struct tag *tag = (struct tag *) object;
 224                 if (revs->tag_objects && !(flags & UNINTERESTING))
 225                         add_pending_object(revs, object, tag->tag);
 226                 if (!tag->tagged)
 227                         die("bad tag");
 228                 object = parse_object(tag->tagged->sha1);
 229                 if (!object) {
 230                         if (flags & UNINTERESTING)
 231                                 return NULL;
 232                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 233                 }
 234                 object->flags |= flags;
 235                 /*
 236                  * We'll handle the tagged object by looping or dropping
 237                  * through to the non-tag handlers below. Do not
 238                  * propagate data from the tag's pending entry.
 239                  */
 240                 name = "";
 241                 path = NULL;
 242                 mode = 0;
 243         }
 244
 245         /*
 246          * Commit object? Just return it, we'll do all the complex
 247          * reachability crud.
 248          */
 249         if (object->type == OBJ_COMMIT) {
 250                 struct commit *commit = (struct commit *)object;
 251                 if (parse_commit(commit) < 0)
 252                         die("unable to parse commit %s", name);
 253                 if (flags & UNINTERESTING) {
 254                         mark_parents_uninteresting(commit);
 255                         revs->limited = 1;
 256                 }
 257                 if (revs->show_source && !commit->util)
 258                         commit->util = xstrdup(name);
 259                 return commit;
 260         }
 261
 262         /*
 263          * Tree object? Either mark it uninteresting, or add it
 264          * to the list of objects to look at later..
 265          */
 266         if (object->type == OBJ_TREE) {
 267                 struct tree *tree = (struct tree *)object;
 268                 if (!revs->tree_objects)
 269                         return NULL;
 270                 if (flags & UNINTERESTING) {
 271                         mark_tree_contents_uninteresting(tree);
 272                         return NULL;
 273                 }
 274                 add_pending_object_with_path(revs, object, name, mode, path);
 275                 return NULL;
 276         }
 277
 278         /*
 279          * Blob object? You know the drill by now..
 280          */
 281         if (object->type == OBJ_BLOB) {
 282                 if (!revs->blob_objects)
 283                         return NULL;
 284                 if (flags & UNINTERESTING)
 285                         return NULL;
 286                 add_pending_object_with_path(revs, object, name, mode, path);
 287                 return NULL;
 288         }
 289         die("%s is unknown object", name);
 290 }
 291
 292 static int everybody_uninteresting(struct commit_list *orig,
 293                                    struct commit **interesting_cache)
 294 {
 295         struct commit_list *list = orig;
 296
 297         if (*interesting_cache) {
 298                 struct commit *commit = *interesting_cache;
 299                 if (!(commit->object.flags & UNINTERESTING))
 300                         return 0;
 301         }
 302
 303         while (list) {
 304                 struct commit *commit = list->item;
 305                 list = list->next;
 306                 if (commit->object.flags & UNINTERESTING)
 307                         continue;
 308
 309                 *interesting_cache = commit;
 310                 return 0;
 311         }
 312         return 1;
 313 }
 314
 315 /*
 316  * A definition of "relevant" commit that we can use to simplify limited graphs
 317  * by eliminating side branches.
 318  *
 319  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
 320  * in our list), or that is a specified BOTTOM commit. Then after computing
 321  * a limited list, during processing we can generally ignore boundary merges
 322  * coming from outside the graph, (ie from irrelevant parents), and treat
 323  * those merges as if they were single-parent. TREESAME is defined to consider
 324  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
 325  * we don't care if we were !TREESAME to non-graph parents.
 326  *
 327  * Treating bottom commits as relevant ensures that a limited graph's
 328  * connection to the actual bottom commit is not viewed as a side branch, but
 329  * treated as part of the graph. For example:
 330  *
 331  *   ....Z...A---X---o---o---B
 332  *        .     /
 333  *         W---Y
 334  *
 335  * When computing "A..B", the A-X connection is at least as important as
 336  * Y-X, despite A being flagged UNINTERESTING.
 337  *
 338  * And when computing --ancestry-path "A..B", the A-X connection is more
 339  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
 340  */
 341 static inline int relevant_commit(struct commit *commit)
 342 {
 343         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
 344 }
 345
 346 /*
 347  * Return a single relevant commit from a parent list. If we are a TREESAME
 348  * commit, and this selects one of our parents, then we can safely simplify to
 349  * that parent.
 350  */
 351 static struct commit *one_relevant_parent(const struct rev_info *revs,
 352                                           struct commit_list *orig)
 353 {
 354         struct commit_list *list = orig;
 355         struct commit *relevant = NULL;
 356
 357         if (!orig)
 358                 return NULL;
 359
 360         /*
 361          * For 1-parent commits, or if first-parent-only, then return that
 362          * first parent (even if not "relevant" by the above definition).
 363          * TREESAME will have been set purely on that parent.
 364          */
 365         if (revs->first_parent_only || !orig->next)
 366                 return orig->item;
 367
 368         /*
 369          * For multi-parent commits, identify a sole relevant parent, if any.
 370          * If we have only one relevant parent, then TREESAME will be set purely
 371          * with regard to that parent, and we can simplify accordingly.
 372          *
 373          * If we have more than one relevant parent, or no relevant parents
 374          * (and multiple irrelevant ones), then we can't select a parent here
 375          * and return NULL.
 376          */
 377         while (list) {
 378                 struct commit *commit = list->item;
 379                 list = list->next;
 380                 if (relevant_commit(commit)) {
 381                         if (relevant)
 382                                 return NULL;
 383                         relevant = commit;
 384                 }
 385         }
 386         return relevant;
 387 }
 388
 389 /*
 390  * The goal is to get REV_TREE_NEW as the result only if the
 391  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 392  * if the whole diff is removal of old data, and otherwise
 393  * REV_TREE_DIFFERENT (of course if the trees are the same we
 394  * want REV_TREE_SAME).
 395  * That means that once we get to REV_TREE_DIFFERENT, we do not
 396  * have to look any further.
 397  */
 398 static int tree_difference = REV_TREE_SAME;
 399
 400 static void file_add_remove(struct diff_options *options,
 401                     int addremove, unsigned mode,
 402                     const unsigned char *sha1,
 403                     int sha1_valid,
 404                     const char *fullpath, unsigned dirty_submodule)
 405 {
 406         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 407
 408         tree_difference |= diff;
 409         if (tree_difference == REV_TREE_DIFFERENT)
 410                 DIFF_OPT_SET(options, HAS_CHANGES);
 411 }
 412
 413 static void file_change(struct diff_options *options,
 414                  unsigned old_mode, unsigned new_mode,
 415                  const unsigned char *old_sha1,
 416                  const unsigned char *new_sha1,
 417                  int old_sha1_valid, int new_sha1_valid,
 418                  const char *fullpath,
 419                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 420 {
 421         tree_difference = REV_TREE_DIFFERENT;
 422         DIFF_OPT_SET(options, HAS_CHANGES);
 423 }
 424
 425 static int rev_compare_tree(struct rev_info *revs,
 426                             struct commit *parent, struct commit *commit)
 427 {
 428         struct tree *t1 = parent->tree;
 429         struct tree *t2 = commit->tree;
 430
 431         if (!t1)
 432                 return REV_TREE_NEW;
 433         if (!t2)
 434                 return REV_TREE_OLD;
 435
 436         if (revs->simplify_by_decoration) {
 437                 /*
 438                  * If we are simplifying by decoration, then the commit
 439                  * is worth showing if it has a tag pointing at it.
 440                  */
 441                 if (get_name_decoration(&commit->object))
 442                         return REV_TREE_DIFFERENT;
 443                 /*
 444                  * A commit that is not pointed by a tag is uninteresting
 445                  * if we are not limited by path.  This means that you will
 446                  * see the usual "commits that touch the paths" plus any
 447                  * tagged commit by specifying both --simplify-by-decoration
 448                  * and pathspec.
 449                  */
 450                 if (!revs->prune_data.nr)
 451                         return REV_TREE_SAME;
 452         }
 453
 454         tree_difference = REV_TREE_SAME;
 455         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 456         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 457                            &revs->pruning) < 0)
 458                 return REV_TREE_DIFFERENT;
 459         return tree_difference;
 460 }
 461
 462 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 463 {
 464         int retval;
 465         struct tree *t1 = commit->tree;
 466
 467         if (!t1)
 468                 return 0;
 469
 470         tree_difference = REV_TREE_SAME;
 471         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 472         retval = diff_tree_sha1(NULL, t1->object.sha1, "", &revs->pruning);
 473
 474         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 475 }
 476
 477 struct treesame_state {
 478         unsigned int nparents;
 479         unsigned char treesame[FLEX_ARRAY];
 480 };
 481
 482 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
 483 {
 484         unsigned n = commit_list_count(commit->parents);
 485         struct treesame_state *st = xcalloc(1, sizeof(*st) + n);
 486         st->nparents = n;
 487         add_decoration(&revs->treesame, &commit->object, st);
 488         return st;
 489 }
 490
 491 /*
 492  * Must be called immediately after removing the nth_parent from a commit's
 493  * parent list, if we are maintaining the per-parent treesame[] decoration.
 494  * This does not recalculate the master TREESAME flag - update_treesame()
 495  * should be called to update it after a sequence of treesame[] modifications
 496  * that may have affected it.
 497  */
 498 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
 499 {
 500         struct treesame_state *st;
 501         int old_same;
 502
 503         if (!commit->parents) {
 504                 /*
 505                  * Have just removed the only parent from a non-merge.
 506                  * Different handling, as we lack decoration.
 507                  */
 508                 if (nth_parent != 0)
 509                         die("compact_treesame %u", nth_parent);
 510                 old_same = !!(commit->object.flags & TREESAME);
 511                 if (rev_same_tree_as_empty(revs, commit))
 512                         commit->object.flags |= TREESAME;
 513                 else
 514                         commit->object.flags &= ~TREESAME;
 515                 return old_same;
 516         }
 517
 518         st = lookup_decoration(&revs->treesame, &commit->object);
 519         if (!st || nth_parent >= st->nparents)
 520                 die("compact_treesame %u", nth_parent);
 521
 522         old_same = st->treesame[nth_parent];
 523         memmove(st->treesame + nth_parent,
 524                 st->treesame + nth_parent + 1,
 525                 st->nparents - nth_parent - 1);
 526
 527         /*
 528          * If we've just become a non-merge commit, update TREESAME
 529          * immediately, and remove the no-longer-needed decoration.
 530          * If still a merge, defer update until update_treesame().
 531          */
 532         if (--st->nparents == 1) {
 533                 if (commit->parents->next)
 534                         die("compact_treesame parents mismatch");
 535                 if (st->treesame[0] && revs->dense)
 536                         commit->object.flags |= TREESAME;
 537                 else
 538                         commit->object.flags &= ~TREESAME;
 539                 free(add_decoration(&revs->treesame, &commit->object, NULL));
 540         }
 541
 542         return old_same;
 543 }
 544
 545 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
 546 {
 547         if (commit->parents && commit->parents->next) {
 548                 unsigned n;
 549                 struct treesame_state *st;
 550                 struct commit_list *p;
 551                 unsigned relevant_parents;
 552                 unsigned relevant_change, irrelevant_change;
 553
 554                 st = lookup_decoration(&revs->treesame, &commit->object);
 555                 if (!st)
 556                         die("update_treesame %s", sha1_to_hex(commit->object.sha1));
 557                 relevant_parents = 0;
 558                 relevant_change = irrelevant_change = 0;
 559                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
 560                         if (relevant_commit(p->item)) {
 561                                 relevant_change |= !st->treesame[n];
 562                                 relevant_parents++;
 563                         } else
 564                                 irrelevant_change |= !st->treesame[n];
 565                 }
 566                 if (relevant_parents ? relevant_change : irrelevant_change)
 567                         commit->object.flags &= ~TREESAME;
 568                 else
 569                         commit->object.flags |= TREESAME;
 570         }
 571
 572         return commit->object.flags & TREESAME;
 573 }
 574
 575 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
 576 {
 577         /*
 578          * TREESAME is irrelevant unless prune && dense;
 579          * if simplify_history is set, we can't have a mixture of TREESAME and
 580          *    !TREESAME INTERESTING parents (and we don't have treesame[]
 581          *    decoration anyway);
 582          * if first_parent_only is set, then the TREESAME flag is locked
 583          *    against the first parent (and again we lack treesame[] decoration).
 584          */
 585         return revs->prune && revs->dense &&
 586                !revs->simplify_history &&
 587                !revs->first_parent_only;
 588 }
 589
 590 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 591 {
 592         struct commit_list **pp, *parent;
 593         struct treesame_state *ts = NULL;
 594         int relevant_change = 0, irrelevant_change = 0;
 595         int relevant_parents, nth_parent;
 596
 597         /*
 598          * If we don't do pruning, everything is interesting
 599          */
 600         if (!revs->prune)
 601                 return;
 602
 603         if (!commit->tree)
 604                 return;
 605
 606         if (!commit->parents) {
 607                 if (rev_same_tree_as_empty(revs, commit))
 608                         commit->object.flags |= TREESAME;
 609                 return;
 610         }
 611
 612         /*
 613          * Normal non-merge commit? If we don't want to make the
 614          * history dense, we consider it always to be a change..
 615          */
 616         if (!revs->dense && !commit->parents->next)
 617                 return;
 618
 619         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
 620              (parent = *pp) != NULL;
 621              pp = &parent->next, nth_parent++) {
 622                 struct commit *p = parent->item;
 623                 if (relevant_commit(p))
 624                         relevant_parents++;
 625
 626                 if (nth_parent == 1) {
 627                         /*
 628                          * This our second loop iteration - so we now know
 629                          * we're dealing with a merge.
 630                          *
 631                          * Do not compare with later parents when we care only about
 632                          * the first parent chain, in order to avoid derailing the
 633                          * traversal to follow a side branch that brought everything
 634                          * in the path we are limited to by the pathspec.
 635                          */
 636                         if (revs->first_parent_only)
 637                                 break;
 638                         /*
 639                          * If this will remain a potentially-simplifiable
 640                          * merge, remember per-parent treesame if needed.
 641                          * Initialise the array with the comparison from our
 642                          * first iteration.
 643                          */
 644                         if (revs->treesame.name &&
 645                             !revs->simplify_history &&
 646                             !(commit->object.flags & UNINTERESTING)) {
 647                                 ts = initialise_treesame(revs, commit);
 648                                 if (!(irrelevant_change || relevant_change))
 649                                         ts->treesame[0] = 1;
 650                         }
 651                 }
 652                 if (parse_commit(p) < 0)
 653                         die("cannot simplify commit %s (because of %s)",
 654                             sha1_to_hex(commit->object.sha1),
 655                             sha1_to_hex(p->object.sha1));
 656                 switch (rev_compare_tree(revs, p, commit)) {
 657                 case REV_TREE_SAME:
 658                         if (!revs->simplify_history || !relevant_commit(p)) {
 659                                 /* Even if a merge with an uninteresting
 660                                  * side branch brought the entire change
 661                                  * we are interested in, we do not want
 662                                  * to lose the other branches of this
 663                                  * merge, so we just keep going.
 664                                  */
 665                                 if (ts)
 666                                         ts->treesame[nth_parent] = 1;
 667                                 continue;
 668                         }
 669                         parent->next = NULL;
 670                         commit->parents = parent;
 671                         commit->object.flags |= TREESAME;
 672                         return;
 673
 674                 case REV_TREE_NEW:
 675                         if (revs->remove_empty_trees &&
 676                             rev_same_tree_as_empty(revs, p)) {
 677                                 /* We are adding all the specified
 678                                  * paths from this parent, so the
 679                                  * history beyond this parent is not
 680                                  * interesting.  Remove its parents
 681                                  * (they are grandparents for us).
 682                                  * IOW, we pretend this parent is a
 683                                  * "root" commit.
 684                                  */
 685                                 if (parse_commit(p) < 0)
 686                                         die("cannot simplify commit %s (invalid %s)",
 687                                             sha1_to_hex(commit->object.sha1),
 688                                             sha1_to_hex(p->object.sha1));
 689                                 p->parents = NULL;
 690                         }
 691                 /* fallthrough */
 692                 case REV_TREE_OLD:
 693                 case REV_TREE_DIFFERENT:
 694                         if (relevant_commit(p))
 695                                 relevant_change = 1;
 696                         else
 697                                 irrelevant_change = 1;
 698                         continue;
 699                 }
 700                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 701         }
 702
 703         /*
 704          * TREESAME is straightforward for single-parent commits. For merge
 705          * commits, it is most useful to define it so that "irrelevant"
 706          * parents cannot make us !TREESAME - if we have any relevant
 707          * parents, then we only consider TREESAMEness with respect to them,
 708          * allowing irrelevant merges from uninteresting branches to be
 709          * simplified away. Only if we have only irrelevant parents do we
 710          * base TREESAME on them. Note that this logic is replicated in
 711          * update_treesame, which should be kept in sync.
 712          */
 713         if (relevant_parents ? !relevant_change : !irrelevant_change)
 714                 commit->object.flags |= TREESAME;
 715 }
 716
 717 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
 718                     struct commit_list *cached_base, struct commit_list **cache)
 719 {
 720         struct commit_list *new_entry;
 721
 722         if (cached_base && p->date < cached_base->item->date)
 723                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
 724         else
 725                 new_entry = commit_list_insert_by_date(p, head);
 726
 727         if (cache && (!*cache || p->date < (*cache)->item->date))
 728                 *cache = new_entry;
 729 }
 730
 731 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 732                     struct commit_list **list, struct commit_list **cache_ptr)
 733 {
 734         struct commit_list *parent = commit->parents;
 735         unsigned left_flag;
 736         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 737
 738         if (commit->object.flags & ADDED)
 739                 return 0;
 740         commit->object.flags |= ADDED;
 741
 742         if (revs->include_check &&
 743             !revs->include_check(commit, revs->include_check_data))
 744                 return 0;
 745
 746         /*
 747          * If the commit is uninteresting, don't try to
 748          * prune parents - we want the maximal uninteresting
 749          * set.
 750          *
 751          * Normally we haven't parsed the parent
 752          * yet, so we won't have a parent of a parent
 753          * here. However, it may turn out that we've
 754          * reached this commit some other way (where it
 755          * wasn't uninteresting), in which case we need
 756          * to mark its parents recursively too..
 757          */
 758         if (commit->object.flags & UNINTERESTING) {
 759                 while (parent) {
 760                         struct commit *p = parent->item;
 761                         parent = parent->next;
 762                         if (p)
 763                                 p->object.flags |= UNINTERESTING;
 764                         if (parse_commit_gently(p, 1) < 0)
 765                                 continue;
 766                         if (p->parents)
 767                                 mark_parents_uninteresting(p);
 768                         if (p->object.flags & SEEN)
 769                                 continue;
 770                         p->object.flags |= SEEN;
 771                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 772                 }
 773                 return 0;
 774         }
 775
 776         /*
 777          * Ok, the commit wasn't uninteresting. Try to
 778          * simplify the commit history and find the parent
 779          * that has no differences in the path set if one exists.
 780          */
 781         try_to_simplify_commit(revs, commit);
 782
 783         if (revs->no_walk)
 784                 return 0;
 785
 786         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 787
 788         for (parent = commit->parents; parent; parent = parent->next) {
 789                 struct commit *p = parent->item;
 790
 791                 if (parse_commit_gently(p, revs->ignore_missing_links) < 0)
 792                         return -1;
 793                 if (revs->show_source && !p->util)
 794                         p->util = commit->util;
 795                 p->object.flags |= left_flag;
 796                 if (!(p->object.flags & SEEN)) {
 797                         p->object.flags |= SEEN;
 798                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 799                 }
 800                 if (revs->first_parent_only)
 801                         break;
 802         }
 803         return 0;
 804 }
 805
 806 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 807 {
 808         struct commit_list *p;
 809         int left_count = 0, right_count = 0;
 810         int left_first;
 811         struct patch_ids ids;
 812         unsigned cherry_flag;
 813
 814         /* First count the commits on the left and on the right */
 815         for (p = list; p; p = p->next) {
 816                 struct commit *commit = p->item;
 817                 unsigned flags = commit->object.flags;
 818                 if (flags & BOUNDARY)
 819                         ;
 820                 else if (flags & SYMMETRIC_LEFT)
 821                         left_count++;
 822                 else
 823                         right_count++;
 824         }
 825
 826         if (!left_count || !right_count)
 827                 return;
 828
 829         left_first = left_count < right_count;
 830         init_patch_ids(&ids);
 831         ids.diffopts.pathspec = revs->diffopt.pathspec;
 832
 833         /* Compute patch-ids for one side */
 834         for (p = list; p; p = p->next) {
 835                 struct commit *commit = p->item;
 836                 unsigned flags = commit->object.flags;
 837
 838                 if (flags & BOUNDARY)
 839                         continue;
 840                 /*
 841                  * If we have fewer left, left_first is set and we omit
 842                  * commits on the right branch in this loop.  If we have
 843                  * fewer right, we skip the left ones.
 844                  */
 845                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 846                         continue;
 847                 commit->util = add_commit_patch_id(commit, &ids);
 848         }
 849
 850         /* either cherry_mark or cherry_pick are true */
 851         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
 852
 853         /* Check the other side */
 854         for (p = list; p; p = p->next) {
 855                 struct commit *commit = p->item;
 856                 struct patch_id *id;
 857                 unsigned flags = commit->object.flags;
 858
 859                 if (flags & BOUNDARY)
 860                         continue;
 861                 /*
 862                  * If we have fewer left, left_first is set and we omit
 863                  * commits on the left branch in this loop.
 864                  */
 865                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 866                         continue;
 867
 868                 /*
 869                  * Have we seen the same patch id?
 870                  */
 871                 id = has_commit_patch_id(commit, &ids);
 872                 if (!id)
 873                         continue;
 874                 id->seen = 1;
 875                 commit->object.flags |= cherry_flag;
 876         }
 877
 878         /* Now check the original side for seen ones */
 879         for (p = list; p; p = p->next) {
 880                 struct commit *commit = p->item;
 881                 struct patch_id *ent;
 882
 883                 ent = commit->util;
 884                 if (!ent)
 885                         continue;
 886                 if (ent->seen)
 887                         commit->object.flags |= cherry_flag;
 888                 commit->util = NULL;
 889         }
 890
 891         free_patch_ids(&ids);
 892 }
 893
 894 /* How many extra uninteresting commits we want to see.. */
 895 #define SLOP 5
 896
 897 static int still_interesting(struct commit_list *src, unsigned long date, int slop,
 898                              struct commit **interesting_cache)
 899 {
 900         /*
 901          * No source list at all? We're definitely done..
 902          */
 903         if (!src)
 904                 return 0;
 905
 906         /*
 907          * Does the destination list contain entries with a date
 908          * before the source list? Definitely _not_ done.
 909          */
 910         if (date <= src->item->date)
 911                 return SLOP;
 912
 913         /*
 914          * Does the source list still have interesting commits in
 915          * it? Definitely not done..
 916          */
 917         if (!everybody_uninteresting(src, interesting_cache))
 918                 return SLOP;
 919
 920         /* Ok, we're closing in.. */
 921         return slop-1;
 922 }
 923
 924 /*
 925  * "rev-list --ancestry-path A..B" computes commits that are ancestors
 926  * of B but not ancestors of A but further limits the result to those
 927  * that are descendants of A.  This takes the list of bottom commits and
 928  * the result of "A..B" without --ancestry-path, and limits the latter
 929  * further to the ones that can reach one of the commits in "bottom".
 930  */
 931 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
 932 {
 933         struct commit_list *p;
 934         struct commit_list *rlist = NULL;
 935         int made_progress;
 936
 937         /*
 938          * Reverse the list so that it will be likely that we would
 939          * process parents before children.
 940          */
 941         for (p = list; p; p = p->next)
 942                 commit_list_insert(p->item, &rlist);
 943
 944         for (p = bottom; p; p = p->next)
 945                 p->item->object.flags |= TMP_MARK;
 946
 947         /*
 948          * Mark the ones that can reach bottom commits in "list",
 949          * in a bottom-up fashion.
 950          */
 951         do {
 952                 made_progress = 0;
 953                 for (p = rlist; p; p = p->next) {
 954                         struct commit *c = p->item;
 955                         struct commit_list *parents;
 956                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
 957                                 continue;
 958                         for (parents = c->parents;
 959                              parents;
 960                              parents = parents->next) {
 961                                 if (!(parents->item->object.flags & TMP_MARK))
 962                                         continue;
 963                                 c->object.flags |= TMP_MARK;
 964                                 made_progress = 1;
 965                                 break;
 966                         }
 967                 }
 968         } while (made_progress);
 969
 970         /*
 971          * NEEDSWORK: decide if we want to remove parents that are
 972          * not marked with TMP_MARK from commit->parents for commits
 973          * in the resulting list.  We may not want to do that, though.
 974          */
 975
 976         /*
 977          * The ones that are not marked with TMP_MARK are uninteresting
 978          */
 979         for (p = list; p; p = p->next) {
 980                 struct commit *c = p->item;
 981                 if (c->object.flags & TMP_MARK)
 982                         continue;
 983                 c->object.flags |= UNINTERESTING;
 984         }
 985
 986         /* We are done with the TMP_MARK */
 987         for (p = list; p; p = p->next)
 988                 p->item->object.flags &= ~TMP_MARK;
 989         for (p = bottom; p; p = p->next)
 990                 p->item->object.flags &= ~TMP_MARK;
 991         free_commit_list(rlist);
 992 }
 993
 994 /*
 995  * Before walking the history, keep the set of "negative" refs the
 996  * caller has asked to exclude.
 997  *
 998  * This is used to compute "rev-list --ancestry-path A..B", as we need
 999  * to filter the result of "A..B" further to the ones that can actually
1000  * reach A.
1001  */
1002 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1003 {
1004         struct commit_list *elem, *bottom = NULL;
1005         for (elem = list; elem; elem = elem->next)
1006                 if (elem->item->object.flags & BOTTOM)
1007                         commit_list_insert(elem->item, &bottom);
1008         return bottom;
1009 }
1010
1011 /* Assumes either left_only or right_only is set */
1012 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1013 {
1014         struct commit_list *p;
1015
1016         for (p = list; p; p = p->next) {
1017                 struct commit *commit = p->item;
1018
1019                 if (revs->right_only) {
1020                         if (commit->object.flags & SYMMETRIC_LEFT)
1021                                 commit->object.flags |= SHOWN;
1022                 } else  /* revs->left_only is set */
1023                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1024                                 commit->object.flags |= SHOWN;
1025         }
1026 }
1027
1028 static int limit_list(struct rev_info *revs)
1029 {
1030         int slop = SLOP;
1031         unsigned long date = ~0ul;
1032         struct commit_list *list = revs->commits;
1033         struct commit_list *newlist = NULL;
1034         struct commit_list **p = &newlist;
1035         struct commit_list *bottom = NULL;
1036         struct commit *interesting_cache = NULL;
1037
1038         if (revs->ancestry_path) {
1039                 bottom = collect_bottom_commits(list);
1040                 if (!bottom)
1041                         die("--ancestry-path given but there are no bottom commits");
1042         }
1043
1044         while (list) {
1045                 struct commit_list *entry = list;
1046                 struct commit *commit = list->item;
1047                 struct object *obj = &commit->object;
1048                 show_early_output_fn_t show;
1049
1050                 list = list->next;
1051                 free(entry);
1052
1053                 if (commit == interesting_cache)
1054                         interesting_cache = NULL;
1055
1056                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1057                         obj->flags |= UNINTERESTING;
1058                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1059                         return -1;
1060                 if (obj->flags & UNINTERESTING) {
1061                         mark_parents_uninteresting(commit);
1062                         if (revs->show_all)
1063                                 p = &commit_list_insert(commit, p)->next;
1064                         slop = still_interesting(list, date, slop, &interesting_cache);
1065                         if (slop)
1066                                 continue;
1067                         /* If showing all, add the whole pending list to the end */
1068                         if (revs->show_all)
1069                                 *p = list;
1070                         break;
1071                 }
1072                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1073                         continue;
1074                 date = commit->date;
1075                 p = &commit_list_insert(commit, p)->next;
1076
1077                 show = show_early_output;
1078                 if (!show)
1079                         continue;
1080
1081                 show(revs, newlist);
1082                 show_early_output = NULL;
1083         }
1084         if (revs->cherry_pick || revs->cherry_mark)
1085                 cherry_pick_list(newlist, revs);
1086
1087         if (revs->left_only || revs->right_only)
1088                 limit_left_right(newlist, revs);
1089
1090         if (bottom) {
1091                 limit_to_ancestry(bottom, newlist);
1092                 free_commit_list(bottom);
1093         }
1094
1095         /*
1096          * Check if any commits have become TREESAME by some of their parents
1097          * becoming UNINTERESTING.
1098          */
1099         if (limiting_can_increase_treesame(revs))
1100                 for (list = newlist; list; list = list->next) {
1101                         struct commit *c = list->item;
1102                         if (c->object.flags & (UNINTERESTING | TREESAME))
1103                                 continue;
1104                         update_treesame(revs, c);
1105                 }
1106
1107         revs->commits = newlist;
1108         return 0;
1109 }
1110
1111 /*
1112  * Add an entry to refs->cmdline with the specified information.
1113  * *name is copied.
1114  */
1115 static void add_rev_cmdline(struct rev_info *revs,
1116                             struct object *item,
1117                             const char *name,
1118                             int whence,
1119                             unsigned flags)
1120 {
1121         struct rev_cmdline_info *info = &revs->cmdline;
1122         int nr = info->nr;
1123
1124         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1125         info->rev[nr].item = item;
1126         info->rev[nr].name = xstrdup(name);
1127         info->rev[nr].whence = whence;
1128         info->rev[nr].flags = flags;
1129         info->nr++;
1130 }
1131
1132 static void add_rev_cmdline_list(struct rev_info *revs,
1133                                  struct commit_list *commit_list,
1134                                  int whence,
1135                                  unsigned flags)
1136 {
1137         while (commit_list) {
1138                 struct object *object = &commit_list->item->object;
1139                 add_rev_cmdline(revs, object, sha1_to_hex(object->sha1),
1140                                 whence, flags);
1141                 commit_list = commit_list->next;
1142         }
1143 }
1144
1145 struct all_refs_cb {
1146         int all_flags;
1147         int warned_bad_reflog;
1148         struct rev_info *all_revs;
1149         const char *name_for_errormsg;
1150 };
1151
1152 int ref_excluded(struct string_list *ref_excludes, const char *path)
1153 {
1154         struct string_list_item *item;
1155
1156         if (!ref_excludes)
1157                 return 0;
1158         for_each_string_list_item(item, ref_excludes) {
1159                 if (!wildmatch(item->string, path, 0, NULL))
1160                         return 1;
1161         }
1162         return 0;
1163 }
1164
1165 static int handle_one_ref(const char *path, const struct object_id *oid,
1166                           int flag, void *cb_data)
1167 {
1168         struct all_refs_cb *cb = cb_data;
1169         struct object *object;
1170
1171         if (ref_excluded(cb->all_revs->ref_excludes, path))
1172             return 0;
1173
1174         object = get_reference(cb->all_revs, path, oid->hash, cb->all_flags);
1175         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1176         add_pending_sha1(cb->all_revs, path, oid->hash, cb->all_flags);
1177         return 0;
1178 }
1179
1180 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1181         unsigned flags)
1182 {
1183         cb->all_revs = revs;
1184         cb->all_flags = flags;
1185 }
1186
1187 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1188 {
1189         if (*ref_excludes_p) {
1190                 string_list_clear(*ref_excludes_p, 0);
1191                 free(*ref_excludes_p);
1192         }
1193         *ref_excludes_p = NULL;
1194 }
1195
1196 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1197 {
1198         if (!*ref_excludes_p) {
1199                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1200                 (*ref_excludes_p)->strdup_strings = 1;
1201         }
1202         string_list_append(*ref_excludes_p, exclude);
1203 }
1204
1205 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
1206                 int (*for_each)(const char *, each_ref_fn, void *))
1207 {
1208         struct all_refs_cb cb;
1209         init_all_refs_cb(&cb, revs, flags);
1210         for_each(submodule, handle_one_ref, &cb);
1211 }
1212
1213 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
1214 {
1215         struct all_refs_cb *cb = cb_data;
1216         if (!is_null_sha1(sha1)) {
1217                 struct object *o = parse_object(sha1);
1218                 if (o) {
1219                         o->flags |= cb->all_flags;
1220                         /* ??? CMDLINEFLAGS ??? */
1221                         add_pending_object(cb->all_revs, o, "");
1222                 }
1223                 else if (!cb->warned_bad_reflog) {
1224                         warning("reflog of '%s' references pruned commits",
1225                                 cb->name_for_errormsg);
1226                         cb->warned_bad_reflog = 1;
1227                 }
1228         }
1229 }
1230
1231 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
1232                 const char *email, unsigned long timestamp, int tz,
1233                 const char *message, void *cb_data)
1234 {
1235         handle_one_reflog_commit(osha1, cb_data);
1236         handle_one_reflog_commit(nsha1, cb_data);
1237         return 0;
1238 }
1239
1240 static int handle_one_reflog(const char *path, const struct object_id *oid,
1241                              int flag, void *cb_data)
1242 {
1243         struct all_refs_cb *cb = cb_data;
1244         cb->warned_bad_reflog = 0;
1245         cb->name_for_errormsg = path;
1246         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
1247         return 0;
1248 }
1249
1250 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1251 {
1252         struct all_refs_cb cb;
1253
1254         cb.all_revs = revs;
1255         cb.all_flags = flags;
1256         for_each_reflog(handle_one_reflog, &cb);
1257 }
1258
1259 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1260                            struct strbuf *path)
1261 {
1262         size_t baselen = path->len;
1263         int i;
1264
1265         if (it->entry_count >= 0) {
1266                 struct tree *tree = lookup_tree(it->sha1);
1267                 add_pending_object_with_path(revs, &tree->object, "",
1268                                              040000, path->buf);
1269         }
1270
1271         for (i = 0; i < it->subtree_nr; i++) {
1272                 struct cache_tree_sub *sub = it->down[i];
1273                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1274                 add_cache_tree(sub->cache_tree, revs, path);
1275                 strbuf_setlen(path, baselen);
1276         }
1277
1278 }
1279
1280 void add_index_objects_to_pending(struct rev_info *revs, unsigned flags)
1281 {
1282         int i;
1283
1284         read_cache();
1285         for (i = 0; i < active_nr; i++) {
1286                 struct cache_entry *ce = active_cache[i];
1287                 struct blob *blob;
1288
1289                 if (S_ISGITLINK(ce->ce_mode))
1290                         continue;
1291
1292                 blob = lookup_blob(ce->sha1);
1293                 if (!blob)
1294                         die("unable to add index blob to traversal");
1295                 add_pending_object_with_path(revs, &blob->object, "",
1296                                              ce->ce_mode, ce->name);
1297         }
1298
1299         if (active_cache_tree) {
1300                 struct strbuf path = STRBUF_INIT;
1301                 add_cache_tree(active_cache_tree, revs, &path);
1302                 strbuf_release(&path);
1303         }
1304 }
1305
1306 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
1307 {
1308         unsigned char sha1[20];
1309         struct object *it;
1310         struct commit *commit;
1311         struct commit_list *parents;
1312         const char *arg = arg_;
1313
1314         if (*arg == '^') {
1315                 flags ^= UNINTERESTING | BOTTOM;
1316                 arg++;
1317         }
1318         if (get_sha1_committish(arg, sha1))
1319                 return 0;
1320         while (1) {
1321                 it = get_reference(revs, arg, sha1, 0);
1322                 if (!it && revs->ignore_missing)
1323                         return 0;
1324                 if (it->type != OBJ_TAG)
1325                         break;
1326                 if (!((struct tag*)it)->tagged)
1327                         return 0;
1328                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
1329         }
1330         if (it->type != OBJ_COMMIT)
1331                 return 0;
1332         commit = (struct commit *)it;
1333         for (parents = commit->parents; parents; parents = parents->next) {
1334                 it = &parents->item->object;
1335                 it->flags |= flags;
1336                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1337                 add_pending_object(revs, it, arg);
1338         }
1339         return 1;
1340 }
1341
1342 void init_revisions(struct rev_info *revs, const char *prefix)
1343 {
1344         memset(revs, 0, sizeof(*revs));
1345
1346         revs->abbrev = DEFAULT_ABBREV;
1347         revs->ignore_merges = 1;
1348         revs->simplify_history = 1;
1349         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
1350         DIFF_OPT_SET(&revs->pruning, QUICK);
1351         revs->pruning.add_remove = file_add_remove;
1352         revs->pruning.change = file_change;
1353         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1354         revs->dense = 1;
1355         revs->prefix = prefix;
1356         revs->max_age = -1;
1357         revs->min_age = -1;
1358         revs->skip_count = -1;
1359         revs->max_count = -1;
1360         revs->max_parents = -1;
1361
1362         revs->commit_format = CMIT_FMT_DEFAULT;
1363
1364         init_grep_defaults();
1365         grep_init(&revs->grep_filter, prefix);
1366         revs->grep_filter.status_only = 1;
1367         revs->grep_filter.regflags = REG_NEWLINE;
1368
1369         diff_setup(&revs->diffopt);
1370         if (prefix && !revs->diffopt.prefix) {
1371                 revs->diffopt.prefix = prefix;
1372                 revs->diffopt.prefix_length = strlen(prefix);
1373         }
1374
1375         revs->notes_opt.use_default_notes = -1;
1376 }
1377
1378 static void add_pending_commit_list(struct rev_info *revs,
1379                                     struct commit_list *commit_list,
1380                                     unsigned int flags)
1381 {
1382         while (commit_list) {
1383                 struct object *object = &commit_list->item->object;
1384                 object->flags |= flags;
1385                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
1386                 commit_list = commit_list->next;
1387         }
1388 }
1389
1390 static void prepare_show_merge(struct rev_info *revs)
1391 {
1392         struct commit_list *bases;
1393         struct commit *head, *other;
1394         unsigned char sha1[20];
1395         const char **prune = NULL;
1396         int i, prune_num = 1; /* counting terminating NULL */
1397
1398         if (get_sha1("HEAD", sha1))
1399                 die("--merge without HEAD?");
1400         head = lookup_commit_or_die(sha1, "HEAD");
1401         if (get_sha1("MERGE_HEAD", sha1))
1402                 die("--merge without MERGE_HEAD?");
1403         other = lookup_commit_or_die(sha1, "MERGE_HEAD");
1404         add_pending_object(revs, &head->object, "HEAD");
1405         add_pending_object(revs, &other->object, "MERGE_HEAD");
1406         bases = get_merge_bases(head, other);
1407         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1408         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1409         free_commit_list(bases);
1410         head->object.flags |= SYMMETRIC_LEFT;
1411
1412         if (!active_nr)
1413                 read_cache();
1414         for (i = 0; i < active_nr; i++) {
1415                 const struct cache_entry *ce = active_cache[i];
1416                 if (!ce_stage(ce))
1417                         continue;
1418                 if (ce_path_match(ce, &revs->prune_data, NULL)) {
1419                         prune_num++;
1420                         REALLOC_ARRAY(prune, prune_num);
1421                         prune[prune_num-2] = ce->name;
1422                         prune[prune_num-1] = NULL;
1423                 }
1424                 while ((i+1 < active_nr) &&
1425                        ce_same_name(ce, active_cache[i+1]))
1426                         i++;
1427         }
1428         free_pathspec(&revs->prune_data);
1429         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1430                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1431         revs->limited = 1;
1432 }
1433
1434 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1435 {
1436         struct object_context oc;
1437         char *dotdot;
1438         struct object *object;
1439         unsigned char sha1[20];
1440         int local_flags;
1441         const char *arg = arg_;
1442         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1443         unsigned get_sha1_flags = 0;
1444
1445         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1446
1447         dotdot = strstr(arg, "..");
1448         if (dotdot) {
1449                 unsigned char from_sha1[20];
1450                 const char *next = dotdot + 2;
1451                 const char *this = arg;
1452                 int symmetric = *next == '.';
1453                 unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1454                 static const char head_by_default[] = "HEAD";
1455                 unsigned int a_flags;
1456
1457                 *dotdot = 0;
1458                 next += symmetric;
1459
1460                 if (!*next)
1461                         next = head_by_default;
1462                 if (dotdot == arg)
1463                         this = head_by_default;
1464                 if (this == head_by_default && next == head_by_default &&
1465                     !symmetric) {
1466                         /*
1467                          * Just ".."?  That is not a range but the
1468                          * pathspec for the parent directory.
1469                          */
1470                         if (!cant_be_filename) {
1471                                 *dotdot = '.';
1472                                 return -1;
1473                         }
1474                 }
1475                 if (!get_sha1_committish(this, from_sha1) &&
1476                     !get_sha1_committish(next, sha1)) {
1477                         struct object *a_obj, *b_obj;
1478
1479                         if (!cant_be_filename) {
1480                                 *dotdot = '.';
1481                                 verify_non_filename(revs->prefix, arg);
1482                         }
1483
1484                         a_obj = parse_object(from_sha1);
1485                         b_obj = parse_object(sha1);
1486                         if (!a_obj || !b_obj) {
1487                         missing:
1488                                 if (revs->ignore_missing)
1489                                         return 0;
1490                                 die(symmetric
1491                                     ? "Invalid symmetric difference expression %s"
1492                                     : "Invalid revision range %s", arg);
1493                         }
1494
1495                         if (!symmetric) {
1496                                 /* just A..B */
1497                                 a_flags = flags_exclude;
1498                         } else {
1499                                 /* A...B -- find merge bases between the two */
1500                                 struct commit *a, *b;
1501                                 struct commit_list *exclude;
1502
1503                                 a = (a_obj->type == OBJ_COMMIT
1504                                      ? (struct commit *)a_obj
1505                                      : lookup_commit_reference(a_obj->sha1));
1506                                 b = (b_obj->type == OBJ_COMMIT
1507                                      ? (struct commit *)b_obj
1508                                      : lookup_commit_reference(b_obj->sha1));
1509                                 if (!a || !b)
1510                                         goto missing;
1511                                 exclude = get_merge_bases(a, b);
1512                                 add_rev_cmdline_list(revs, exclude,
1513                                                      REV_CMD_MERGE_BASE,
1514                                                      flags_exclude);
1515                                 add_pending_commit_list(revs, exclude,
1516                                                         flags_exclude);
1517                                 free_commit_list(exclude);
1518
1519                                 a_flags = flags | SYMMETRIC_LEFT;
1520                         }
1521
1522                         a_obj->flags |= a_flags;
1523                         b_obj->flags |= flags;
1524                         add_rev_cmdline(revs, a_obj, this,
1525                                         REV_CMD_LEFT, a_flags);
1526                         add_rev_cmdline(revs, b_obj, next,
1527                                         REV_CMD_RIGHT, flags);
1528                         add_pending_object(revs, a_obj, this);
1529                         add_pending_object(revs, b_obj, next);
1530                         return 0;
1531                 }
1532                 *dotdot = '.';
1533         }
1534         dotdot = strstr(arg, "^@");
1535         if (dotdot && !dotdot[2]) {
1536                 *dotdot = 0;
1537                 if (add_parents_only(revs, arg, flags))
1538                         return 0;
1539                 *dotdot = '^';
1540         }
1541         dotdot = strstr(arg, "^!");
1542         if (dotdot && !dotdot[2]) {
1543                 *dotdot = 0;
1544                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM)))
1545                         *dotdot = '^';
1546         }
1547
1548         local_flags = 0;
1549         if (*arg == '^') {
1550                 local_flags = UNINTERESTING | BOTTOM;
1551                 arg++;
1552         }
1553
1554         if (revarg_opt & REVARG_COMMITTISH)
1555                 get_sha1_flags = GET_SHA1_COMMITTISH;
1556
1557         if (get_sha1_with_context(arg, get_sha1_flags, sha1, &oc))
1558                 return revs->ignore_missing ? 0 : -1;
1559         if (!cant_be_filename)
1560                 verify_non_filename(revs->prefix, arg);
1561         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1562         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1563         add_pending_object_with_mode(revs, object, arg, oc.mode);
1564         return 0;
1565 }
1566
1567 struct cmdline_pathspec {
1568         int alloc;
1569         int nr;
1570         const char **path;
1571 };
1572
1573 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
1574 {
1575         while (*av) {
1576                 ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
1577                 prune->path[prune->nr++] = *(av++);
1578         }
1579 }
1580
1581 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1582                                      struct cmdline_pathspec *prune)
1583 {
1584         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1585                 int len = sb->len;
1586                 if (len && sb->buf[len - 1] == '\n')
1587                         sb->buf[--len] = '\0';
1588                 ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
1589                 prune->path[prune->nr++] = xstrdup(sb->buf);
1590         }
1591 }
1592
1593 static void read_revisions_from_stdin(struct rev_info *revs,
1594                                       struct cmdline_pathspec *prune)
1595 {
1596         struct strbuf sb;
1597         int seen_dashdash = 0;
1598         int save_warning;
1599
1600         save_warning = warn_on_object_refname_ambiguity;
1601         warn_on_object_refname_ambiguity = 0;
1602
1603         strbuf_init(&sb, 1000);
1604         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1605                 int len = sb.len;
1606                 if (len && sb.buf[len - 1] == '\n')
1607                         sb.buf[--len] = '\0';
1608                 if (!len)
1609                         break;
1610                 if (sb.buf[0] == '-') {
1611                         if (len == 2 && sb.buf[1] == '-') {
1612                                 seen_dashdash = 1;
1613                                 break;
1614                         }
1615                         die("options not supported in --stdin mode");
1616                 }
1617                 if (handle_revision_arg(sb.buf, revs, 0,
1618                                         REVARG_CANNOT_BE_FILENAME))
1619                         die("bad revision '%s'", sb.buf);
1620         }
1621         if (seen_dashdash)
1622                 read_pathspec_from_stdin(revs, &sb, prune);
1623
1624         strbuf_release(&sb);
1625         warn_on_object_refname_ambiguity = save_warning;
1626 }
1627
1628 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1629 {
1630         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1631 }
1632
1633 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1634 {
1635         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1636 }
1637
1638 static void add_message_grep(struct rev_info *revs, const char *pattern)
1639 {
1640         add_grep(revs, pattern, GREP_PATTERN_BODY);
1641 }
1642
1643 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1644                                int *unkc, const char **unkv)
1645 {
1646         const char *arg = argv[0];
1647         const char *optarg;
1648         int argcount;
1649
1650         /* pseudo revision arguments */
1651         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1652             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1653             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1654             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1655             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1656             !strcmp(arg, "--indexed-objects") ||
1657             starts_with(arg, "--exclude=") ||
1658             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1659             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1660         {
1661                 unkv[(*unkc)++] = arg;
1662                 return 1;
1663         }
1664
1665         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1666                 revs->max_count = atoi(optarg);
1667                 revs->no_walk = 0;
1668                 return argcount;
1669         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1670                 revs->skip_count = atoi(optarg);
1671                 return argcount;
1672         } else if ((*arg == '-') && isdigit(arg[1])) {
1673                 /* accept -<digit>, like traditional "head" */
1674                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1675                     revs->max_count < 0)
1676                         die("'%s': not a non-negative integer", arg + 1);
1677                 revs->no_walk = 0;
1678         } else if (!strcmp(arg, "-n")) {
1679                 if (argc <= 1)
1680                         return error("-n requires an argument");
1681                 revs->max_count = atoi(argv[1]);
1682                 revs->no_walk = 0;
1683                 return 2;
1684         } else if (starts_with(arg, "-n")) {
1685                 revs->max_count = atoi(arg + 2);
1686                 revs->no_walk = 0;
1687         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1688                 revs->max_age = atoi(optarg);
1689                 return argcount;
1690         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1691                 revs->max_age = approxidate(optarg);
1692                 return argcount;
1693         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1694                 revs->max_age = approxidate(optarg);
1695                 return argcount;
1696         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1697                 revs->min_age = atoi(optarg);
1698                 return argcount;
1699         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1700                 revs->min_age = approxidate(optarg);
1701                 return argcount;
1702         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1703                 revs->min_age = approxidate(optarg);
1704                 return argcount;
1705         } else if (!strcmp(arg, "--first-parent")) {
1706                 revs->first_parent_only = 1;
1707         } else if (!strcmp(arg, "--ancestry-path")) {
1708                 revs->ancestry_path = 1;
1709                 revs->simplify_history = 0;
1710                 revs->limited = 1;
1711         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1712                 init_reflog_walk(&revs->reflog_info);
1713         } else if (!strcmp(arg, "--default")) {
1714                 if (argc <= 1)
1715                         return error("bad --default argument");
1716                 revs->def = argv[1];
1717                 return 2;
1718         } else if (!strcmp(arg, "--merge")) {
1719                 revs->show_merge = 1;
1720         } else if (!strcmp(arg, "--topo-order")) {
1721                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1722                 revs->topo_order = 1;
1723         } else if (!strcmp(arg, "--simplify-merges")) {
1724                 revs->simplify_merges = 1;
1725                 revs->topo_order = 1;
1726                 revs->rewrite_parents = 1;
1727                 revs->simplify_history = 0;
1728                 revs->limited = 1;
1729         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1730                 revs->simplify_merges = 1;
1731                 revs->topo_order = 1;
1732                 revs->rewrite_parents = 1;
1733                 revs->simplify_history = 0;
1734                 revs->simplify_by_decoration = 1;
1735                 revs->limited = 1;
1736                 revs->prune = 1;
1737                 load_ref_decorations(DECORATE_SHORT_REFS);
1738         } else if (!strcmp(arg, "--date-order")) {
1739                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
1740                 revs->topo_order = 1;
1741         } else if (!strcmp(arg, "--author-date-order")) {
1742                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
1743                 revs->topo_order = 1;
1744         } else if (starts_with(arg, "--early-output")) {
1745                 int count = 100;
1746                 switch (arg[14]) {
1747                 case '=':
1748                         count = atoi(arg+15);
1749                         /* Fallthrough */
1750                 case 0:
1751                         revs->topo_order = 1;
1752                        revs->early_output = count;
1753                 }
1754         } else if (!strcmp(arg, "--parents")) {
1755                 revs->rewrite_parents = 1;
1756                 revs->print_parents = 1;
1757         } else if (!strcmp(arg, "--dense")) {
1758                 revs->dense = 1;
1759         } else if (!strcmp(arg, "--sparse")) {
1760                 revs->dense = 0;
1761         } else if (!strcmp(arg, "--show-all")) {
1762                 revs->show_all = 1;
1763         } else if (!strcmp(arg, "--remove-empty")) {
1764                 revs->remove_empty_trees = 1;
1765         } else if (!strcmp(arg, "--merges")) {
1766                 revs->min_parents = 2;
1767         } else if (!strcmp(arg, "--no-merges")) {
1768                 revs->max_parents = 1;
1769         } else if (starts_with(arg, "--min-parents=")) {
1770                 revs->min_parents = atoi(arg+14);
1771         } else if (starts_with(arg, "--no-min-parents")) {
1772                 revs->min_parents = 0;
1773         } else if (starts_with(arg, "--max-parents=")) {
1774                 revs->max_parents = atoi(arg+14);
1775         } else if (starts_with(arg, "--no-max-parents")) {
1776                 revs->max_parents = -1;
1777         } else if (!strcmp(arg, "--boundary")) {
1778                 revs->boundary = 1;
1779         } else if (!strcmp(arg, "--left-right")) {
1780                 revs->left_right = 1;
1781         } else if (!strcmp(arg, "--left-only")) {
1782                 if (revs->right_only)
1783                         die("--left-only is incompatible with --right-only"
1784                             " or --cherry");
1785                 revs->left_only = 1;
1786         } else if (!strcmp(arg, "--right-only")) {
1787                 if (revs->left_only)
1788                         die("--right-only is incompatible with --left-only");
1789                 revs->right_only = 1;
1790         } else if (!strcmp(arg, "--cherry")) {
1791                 if (revs->left_only)
1792                         die("--cherry is incompatible with --left-only");
1793                 revs->cherry_mark = 1;
1794                 revs->right_only = 1;
1795                 revs->max_parents = 1;
1796                 revs->limited = 1;
1797         } else if (!strcmp(arg, "--count")) {
1798                 revs->count = 1;
1799         } else if (!strcmp(arg, "--cherry-mark")) {
1800                 if (revs->cherry_pick)
1801                         die("--cherry-mark is incompatible with --cherry-pick");
1802                 revs->cherry_mark = 1;
1803                 revs->limited = 1; /* needs limit_list() */
1804         } else if (!strcmp(arg, "--cherry-pick")) {
1805                 if (revs->cherry_mark)
1806                         die("--cherry-pick is incompatible with --cherry-mark");
1807                 revs->cherry_pick = 1;
1808                 revs->limited = 1;
1809         } else if (!strcmp(arg, "--objects")) {
1810                 revs->tag_objects = 1;
1811                 revs->tree_objects = 1;
1812                 revs->blob_objects = 1;
1813         } else if (!strcmp(arg, "--objects-edge")) {
1814                 revs->tag_objects = 1;
1815                 revs->tree_objects = 1;
1816                 revs->blob_objects = 1;
1817                 revs->edge_hint = 1;
1818         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
1819                 revs->tag_objects = 1;
1820                 revs->tree_objects = 1;
1821                 revs->blob_objects = 1;
1822                 revs->edge_hint = 1;
1823                 revs->edge_hint_aggressive = 1;
1824         } else if (!strcmp(arg, "--verify-objects")) {
1825                 revs->tag_objects = 1;
1826                 revs->tree_objects = 1;
1827                 revs->blob_objects = 1;
1828                 revs->verify_objects = 1;
1829         } else if (!strcmp(arg, "--unpacked")) {
1830                 revs->unpacked = 1;
1831         } else if (starts_with(arg, "--unpacked=")) {
1832                 die("--unpacked=<packfile> no longer supported.");
1833         } else if (!strcmp(arg, "-r")) {
1834                 revs->diff = 1;
1835                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1836         } else if (!strcmp(arg, "-t")) {
1837                 revs->diff = 1;
1838                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1839                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1840         } else if (!strcmp(arg, "-m")) {
1841                 revs->ignore_merges = 0;
1842         } else if (!strcmp(arg, "-c")) {
1843                 revs->diff = 1;
1844                 revs->dense_combined_merges = 0;
1845                 revs->combine_merges = 1;
1846         } else if (!strcmp(arg, "--cc")) {
1847                 revs->diff = 1;
1848                 revs->dense_combined_merges = 1;
1849                 revs->combine_merges = 1;
1850         } else if (!strcmp(arg, "-v")) {
1851                 revs->verbose_header = 1;
1852         } else if (!strcmp(arg, "--pretty")) {
1853                 revs->verbose_header = 1;
1854                 revs->pretty_given = 1;
1855                 get_commit_format(NULL, revs);
1856         } else if (starts_with(arg, "--pretty=") || starts_with(arg, "--format=")) {
1857                 /*
1858                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1859                  * not allowed, since the argument is optional.
1860                  */
1861                 revs->verbose_header = 1;
1862                 revs->pretty_given = 1;
1863                 get_commit_format(arg+9, revs);
1864         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1865                 revs->show_notes = 1;
1866                 revs->show_notes_given = 1;
1867                 revs->notes_opt.use_default_notes = 1;
1868         } else if (!strcmp(arg, "--show-signature")) {
1869                 revs->show_signature = 1;
1870         } else if (!strcmp(arg, "--show-linear-break") ||
1871                    starts_with(arg, "--show-linear-break=")) {
1872                 if (starts_with(arg, "--show-linear-break="))
1873                         revs->break_bar = xstrdup(arg + 20);
1874                 else
1875                         revs->break_bar = "                    ..........";
1876                 revs->track_linear = 1;
1877                 revs->track_first_time = 1;
1878         } else if (starts_with(arg, "--show-notes=") ||
1879                    starts_with(arg, "--notes=")) {
1880                 struct strbuf buf = STRBUF_INIT;
1881                 revs->show_notes = 1;
1882                 revs->show_notes_given = 1;
1883                 if (starts_with(arg, "--show-notes")) {
1884                         if (revs->notes_opt.use_default_notes < 0)
1885                                 revs->notes_opt.use_default_notes = 1;
1886                         strbuf_addstr(&buf, arg+13);
1887                 }
1888                 else
1889                         strbuf_addstr(&buf, arg+8);
1890                 expand_notes_ref(&buf);
1891                 string_list_append(&revs->notes_opt.extra_notes_refs,
1892                                    strbuf_detach(&buf, NULL));
1893         } else if (!strcmp(arg, "--no-notes")) {
1894                 revs->show_notes = 0;
1895                 revs->show_notes_given = 1;
1896                 revs->notes_opt.use_default_notes = -1;
1897                 /* we have been strdup'ing ourselves, so trick
1898                  * string_list into free()ing strings */
1899                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1900                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1901                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1902         } else if (!strcmp(arg, "--standard-notes")) {
1903                 revs->show_notes_given = 1;
1904                 revs->notes_opt.use_default_notes = 1;
1905         } else if (!strcmp(arg, "--no-standard-notes")) {
1906                 revs->notes_opt.use_default_notes = 0;
1907         } else if (!strcmp(arg, "--oneline")) {
1908                 revs->verbose_header = 1;
1909                 get_commit_format("oneline", revs);
1910                 revs->pretty_given = 1;
1911                 revs->abbrev_commit = 1;
1912         } else if (!strcmp(arg, "--graph")) {
1913                 revs->topo_order = 1;
1914                 revs->rewrite_parents = 1;
1915                 revs->graph = graph_init(revs);
1916         } else if (!strcmp(arg, "--root")) {
1917                 revs->show_root_diff = 1;
1918         } else if (!strcmp(arg, "--no-commit-id")) {
1919                 revs->no_commit_id = 1;
1920         } else if (!strcmp(arg, "--always")) {
1921                 revs->always_show_header = 1;
1922         } else if (!strcmp(arg, "--no-abbrev")) {
1923                 revs->abbrev = 0;
1924         } else if (!strcmp(arg, "--abbrev")) {
1925                 revs->abbrev = DEFAULT_ABBREV;
1926         } else if (starts_with(arg, "--abbrev=")) {
1927                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1928                 if (revs->abbrev < MINIMUM_ABBREV)
1929                         revs->abbrev = MINIMUM_ABBREV;
1930                 else if (revs->abbrev > 40)
1931                         revs->abbrev = 40;
1932         } else if (!strcmp(arg, "--abbrev-commit")) {
1933                 revs->abbrev_commit = 1;
1934                 revs->abbrev_commit_given = 1;
1935         } else if (!strcmp(arg, "--no-abbrev-commit")) {
1936                 revs->abbrev_commit = 0;
1937         } else if (!strcmp(arg, "--full-diff")) {
1938                 revs->diff = 1;
1939                 revs->full_diff = 1;
1940         } else if (!strcmp(arg, "--full-history")) {
1941                 revs->simplify_history = 0;
1942         } else if (!strcmp(arg, "--relative-date")) {
1943                 revs->date_mode = DATE_RELATIVE;
1944                 revs->date_mode_explicit = 1;
1945         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1946                 revs->date_mode = parse_date_format(optarg);
1947                 revs->date_mode_explicit = 1;
1948                 return argcount;
1949         } else if (!strcmp(arg, "--log-size")) {
1950                 revs->show_log_size = 1;
1951         }
1952         /*
1953          * Grepping the commit log
1954          */
1955         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1956                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1957                 return argcount;
1958         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1959                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1960                 return argcount;
1961         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
1962                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
1963                 return argcount;
1964         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1965                 add_message_grep(revs, optarg);
1966                 return argcount;
1967         } else if (!strcmp(arg, "--grep-debug")) {
1968                 revs->grep_filter.debug = 1;
1969         } else if (!strcmp(arg, "--basic-regexp")) {
1970                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_BRE, &revs->grep_filter);
1971         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1972                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, &revs->grep_filter);
1973         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1974                 revs->grep_filter.regflags |= REG_ICASE;
1975                 DIFF_OPT_SET(&revs->diffopt, PICKAXE_IGNORE_CASE);
1976         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1977                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_FIXED, &revs->grep_filter);
1978         } else if (!strcmp(arg, "--perl-regexp")) {
1979                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
1980         } else if (!strcmp(arg, "--all-match")) {
1981                 revs->grep_filter.all_match = 1;
1982         } else if (!strcmp(arg, "--invert-grep")) {
1983                 revs->invert_grep = 1;
1984         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1985                 if (strcmp(optarg, "none"))
1986                         git_log_output_encoding = xstrdup(optarg);
1987                 else
1988                         git_log_output_encoding = "";
1989                 return argcount;
1990         } else if (!strcmp(arg, "--reverse")) {
1991                 revs->reverse ^= 1;
1992         } else if (!strcmp(arg, "--children")) {
1993                 revs->children.name = "children";
1994                 revs->limited = 1;
1995         } else if (!strcmp(arg, "--ignore-missing")) {
1996                 revs->ignore_missing = 1;
1997         } else {
1998                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1999                 if (!opts)
2000                         unkv[(*unkc)++] = arg;
2001                 return opts;
2002         }
2003         if (revs->graph && revs->track_linear)
2004                 die("--show-linear-break and --graph are incompatible");
2005
2006         return 1;
2007 }
2008
2009 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2010                         const struct option *options,
2011                         const char * const usagestr[])
2012 {
2013         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2014                                     &ctx->cpidx, ctx->out);
2015         if (n <= 0) {
2016                 error("unknown option `%s'", ctx->argv[0]);
2017                 usage_with_options(usagestr, options);
2018         }
2019         ctx->argv += n;
2020         ctx->argc -= n;
2021 }
2022
2023 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2024 {
2025         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
2026 }
2027
2028 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2029 {
2030         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
2031 }
2032
2033 static int handle_revision_pseudo_opt(const char *submodule,
2034                                 struct rev_info *revs,
2035                                 int argc, const char **argv, int *flags)
2036 {
2037         const char *arg = argv[0];
2038         const char *optarg;
2039         int argcount;
2040
2041         /*
2042          * NOTE!
2043          *
2044          * Commands like "git shortlog" will not accept the options below
2045          * unless parse_revision_opt queues them (as opposed to erroring
2046          * out).
2047          *
2048          * When implementing your new pseudo-option, remember to
2049          * register it in the list at the top of handle_revision_opt.
2050          */
2051         if (!strcmp(arg, "--all")) {
2052                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
2053                 handle_refs(submodule, revs, *flags, head_ref_submodule);
2054                 clear_ref_exclusion(&revs->ref_excludes);
2055         } else if (!strcmp(arg, "--branches")) {
2056                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
2057                 clear_ref_exclusion(&revs->ref_excludes);
2058         } else if (!strcmp(arg, "--bisect")) {
2059                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
2060                 handle_refs(submodule, revs, *flags ^ (UNINTERESTING | BOTTOM), for_each_good_bisect_ref);
2061                 revs->bisect = 1;
2062         } else if (!strcmp(arg, "--tags")) {
2063                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
2064                 clear_ref_exclusion(&revs->ref_excludes);
2065         } else if (!strcmp(arg, "--remotes")) {
2066                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
2067                 clear_ref_exclusion(&revs->ref_excludes);
2068         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2069                 struct all_refs_cb cb;
2070                 init_all_refs_cb(&cb, revs, *flags);
2071                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2072                 clear_ref_exclusion(&revs->ref_excludes);
2073                 return argcount;
2074         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2075                 add_ref_exclusion(&revs->ref_excludes, optarg);
2076                 return argcount;
2077         } else if (starts_with(arg, "--branches=")) {
2078                 struct all_refs_cb cb;
2079                 init_all_refs_cb(&cb, revs, *flags);
2080                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
2081                 clear_ref_exclusion(&revs->ref_excludes);
2082         } else if (starts_with(arg, "--tags=")) {
2083                 struct all_refs_cb cb;
2084                 init_all_refs_cb(&cb, revs, *flags);
2085                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
2086                 clear_ref_exclusion(&revs->ref_excludes);
2087         } else if (starts_with(arg, "--remotes=")) {
2088                 struct all_refs_cb cb;
2089                 init_all_refs_cb(&cb, revs, *flags);
2090                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
2091                 clear_ref_exclusion(&revs->ref_excludes);
2092         } else if (!strcmp(arg, "--reflog")) {
2093                 add_reflogs_to_pending(revs, *flags);
2094         } else if (!strcmp(arg, "--indexed-objects")) {
2095                 add_index_objects_to_pending(revs, *flags);
2096         } else if (!strcmp(arg, "--not")) {
2097                 *flags ^= UNINTERESTING | BOTTOM;
2098         } else if (!strcmp(arg, "--no-walk")) {
2099                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2100         } else if (starts_with(arg, "--no-walk=")) {
2101                 /*
2102                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2103                  * not allowed, since the argument is optional.
2104                  */
2105                 if (!strcmp(arg + 10, "sorted"))
2106                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2107                 else if (!strcmp(arg + 10, "unsorted"))
2108                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2109                 else
2110                         return error("invalid argument to --no-walk");
2111         } else if (!strcmp(arg, "--do-walk")) {
2112                 revs->no_walk = 0;
2113         } else {
2114                 return 0;
2115         }
2116
2117         return 1;
2118 }
2119
2120 static void NORETURN diagnose_missing_default(const char *def)
2121 {
2122         unsigned char sha1[20];
2123         int flags;
2124         const char *refname;
2125
2126         refname = resolve_ref_unsafe(def, 0, sha1, &flags);
2127         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2128                 die(_("your current branch appears to be broken"));
2129
2130         skip_prefix(refname, "refs/heads/", &refname);
2131         die(_("your current branch '%s' does not have any commits yet"),
2132             refname);
2133 }
2134
2135 /*
2136  * Parse revision information, filling in the "rev_info" structure,
2137  * and removing the used arguments from the argument list.
2138  *
2139  * Returns the number of arguments left that weren't recognized
2140  * (which are also moved to the head of the argument list)
2141  */
2142 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2143 {
2144         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
2145         struct cmdline_pathspec prune_data;
2146         const char *submodule = NULL;
2147
2148         memset(&prune_data, 0, sizeof(prune_data));
2149         if (opt)
2150                 submodule = opt->submodule;
2151
2152         /* First, search for "--" */
2153         if (opt && opt->assume_dashdash) {
2154                 seen_dashdash = 1;
2155         } else {
2156                 seen_dashdash = 0;
2157                 for (i = 1; i < argc; i++) {
2158                         const char *arg = argv[i];
2159                         if (strcmp(arg, "--"))
2160                                 continue;
2161                         argv[i] = NULL;
2162                         argc = i;
2163                         if (argv[i + 1])
2164                                 append_prune_data(&prune_data, argv + i + 1);
2165                         seen_dashdash = 1;
2166                         break;
2167                 }
2168         }
2169
2170         /* Second, deal with arguments and options */
2171         flags = 0;
2172         revarg_opt = opt ? opt->revarg_opt : 0;
2173         if (seen_dashdash)
2174                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2175         read_from_stdin = 0;
2176         for (left = i = 1; i < argc; i++) {
2177                 const char *arg = argv[i];
2178                 if (*arg == '-') {
2179                         int opts;
2180
2181                         opts = handle_revision_pseudo_opt(submodule,
2182                                                 revs, argc - i, argv + i,
2183                                                 &flags);
2184                         if (opts > 0) {
2185                                 i += opts - 1;
2186                                 continue;
2187                         }
2188
2189                         if (!strcmp(arg, "--stdin")) {
2190                                 if (revs->disable_stdin) {
2191                                         argv[left++] = arg;
2192                                         continue;
2193                                 }
2194                                 if (read_from_stdin++)
2195                                         die("--stdin given twice?");
2196                                 read_revisions_from_stdin(revs, &prune_data);
2197                                 continue;
2198                         }
2199
2200                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2201                         if (opts > 0) {
2202                                 i += opts - 1;
2203                                 continue;
2204                         }
2205                         if (opts < 0)
2206                                 exit(128);
2207                         continue;
2208                 }
2209
2210
2211                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2212                         int j;
2213                         if (seen_dashdash || *arg == '^')
2214                                 die("bad revision '%s'", arg);
2215
2216                         /* If we didn't have a "--":
2217                          * (1) all filenames must exist;
2218                          * (2) all rev-args must not be interpretable
2219                          *     as a valid filename.
2220                          * but the latter we have checked in the main loop.
2221                          */
2222                         for (j = i; j < argc; j++)
2223                                 verify_filename(revs->prefix, argv[j], j == i);
2224
2225                         append_prune_data(&prune_data, argv + i);
2226                         break;
2227                 }
2228                 else
2229                         got_rev_arg = 1;
2230         }
2231
2232         if (prune_data.nr) {
2233                 /*
2234                  * If we need to introduce the magic "a lone ':' means no
2235                  * pathspec whatsoever", here is the place to do so.
2236                  *
2237                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2238                  *      prune_data.nr = 0;
2239                  *      prune_data.alloc = 0;
2240                  *      free(prune_data.path);
2241                  *      prune_data.path = NULL;
2242                  * } else {
2243                  *      terminate prune_data.alloc with NULL and
2244                  *      call init_pathspec() to set revs->prune_data here.
2245                  * }
2246                  */
2247                 ALLOC_GROW(prune_data.path, prune_data.nr + 1, prune_data.alloc);
2248                 prune_data.path[prune_data.nr++] = NULL;
2249                 parse_pathspec(&revs->prune_data, 0, 0,
2250                                revs->prefix, prune_data.path);
2251         }
2252
2253         if (revs->def == NULL)
2254                 revs->def = opt ? opt->def : NULL;
2255         if (opt && opt->tweak)
2256                 opt->tweak(revs, opt);
2257         if (revs->show_merge)
2258                 prepare_show_merge(revs);
2259         if (revs->def && !revs->pending.nr && !got_rev_arg) {
2260                 unsigned char sha1[20];
2261                 struct object *object;
2262                 struct object_context oc;
2263                 if (get_sha1_with_context(revs->def, 0, sha1, &oc))
2264                         diagnose_missing_default(revs->def);
2265                 object = get_reference(revs, revs->def, sha1, 0);
2266                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2267         }
2268
2269         /* Did the user ask for any diff output? Run the diff! */
2270         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2271                 revs->diff = 1;
2272
2273         /* Pickaxe, diff-filter and rename following need diffs */
2274         if (revs->diffopt.pickaxe ||
2275             revs->diffopt.filter ||
2276             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2277                 revs->diff = 1;
2278
2279         if (revs->topo_order)
2280                 revs->limited = 1;
2281
2282         if (revs->prune_data.nr) {
2283                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2284                 /* Can't prune commits with rename following: the paths change.. */
2285                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2286                         revs->prune = 1;
2287                 if (!revs->full_diff)
2288                         copy_pathspec(&revs->diffopt.pathspec,
2289                                       &revs->prune_data);
2290         }
2291         if (revs->combine_merges)
2292                 revs->ignore_merges = 0;
2293         revs->diffopt.abbrev = revs->abbrev;
2294
2295         if (revs->line_level_traverse) {
2296                 revs->limited = 1;
2297                 revs->topo_order = 1;
2298         }
2299
2300         diff_setup_done(&revs->diffopt);
2301
2302         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2303                                  &revs->grep_filter);
2304         compile_grep_patterns(&revs->grep_filter);
2305
2306         if (revs->reverse && revs->reflog_info)
2307                 die("cannot combine --reverse with --walk-reflogs");
2308         if (revs->rewrite_parents && revs->children.name)
2309                 die("cannot combine --parents and --children");
2310
2311         /*
2312          * Limitations on the graph functionality
2313          */
2314         if (revs->reverse && revs->graph)
2315                 die("cannot combine --reverse with --graph");
2316
2317         if (revs->reflog_info && revs->graph)
2318                 die("cannot combine --walk-reflogs with --graph");
2319         if (revs->no_walk && revs->graph)
2320                 die("cannot combine --no-walk with --graph");
2321         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2322                 die("cannot use --grep-reflog without --walk-reflogs");
2323
2324         if (revs->first_parent_only && revs->bisect)
2325                 die(_("--first-parent is incompatible with --bisect"));
2326
2327         return left;
2328 }
2329
2330 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2331 {
2332         struct commit_list *l = xcalloc(1, sizeof(*l));
2333
2334         l->item = child;
2335         l->next = add_decoration(&revs->children, &parent->object, l);
2336 }
2337
2338 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2339 {
2340         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2341         struct commit_list **pp, *p;
2342         int surviving_parents;
2343
2344         /* Examine existing parents while marking ones we have seen... */
2345         pp = &commit->parents;
2346         surviving_parents = 0;
2347         while ((p = *pp) != NULL) {
2348                 struct commit *parent = p->item;
2349                 if (parent->object.flags & TMP_MARK) {
2350                         *pp = p->next;
2351                         if (ts)
2352                                 compact_treesame(revs, commit, surviving_parents);
2353                         continue;
2354                 }
2355                 parent->object.flags |= TMP_MARK;
2356                 surviving_parents++;
2357                 pp = &p->next;
2358         }
2359         /* clear the temporary mark */
2360         for (p = commit->parents; p; p = p->next) {
2361                 p->item->object.flags &= ~TMP_MARK;
2362         }
2363         /* no update_treesame() - removing duplicates can't affect TREESAME */
2364         return surviving_parents;
2365 }
2366
2367 struct merge_simplify_state {
2368         struct commit *simplified;
2369 };
2370
2371 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2372 {
2373         struct merge_simplify_state *st;
2374
2375         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2376         if (!st) {
2377                 st = xcalloc(1, sizeof(*st));
2378                 add_decoration(&revs->merge_simplification, &commit->object, st);
2379         }
2380         return st;
2381 }
2382
2383 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2384 {
2385         struct commit_list *h = reduce_heads(commit->parents);
2386         int i = 0, marked = 0;
2387         struct commit_list *po, *pn;
2388
2389         /* Want these for sanity-checking only */
2390         int orig_cnt = commit_list_count(commit->parents);
2391         int cnt = commit_list_count(h);
2392
2393         /*
2394          * Not ready to remove items yet, just mark them for now, based
2395          * on the output of reduce_heads(). reduce_heads outputs the reduced
2396          * set in its original order, so this isn't too hard.
2397          */
2398         po = commit->parents;
2399         pn = h;
2400         while (po) {
2401                 if (pn && po->item == pn->item) {
2402                         pn = pn->next;
2403                         i++;
2404                 } else {
2405                         po->item->object.flags |= TMP_MARK;
2406                         marked++;
2407                 }
2408                 po=po->next;
2409         }
2410
2411         if (i != cnt || cnt+marked != orig_cnt)
2412                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2413
2414         free_commit_list(h);
2415
2416         return marked;
2417 }
2418
2419 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2420 {
2421         struct commit_list *p;
2422         int marked = 0;
2423
2424         for (p = commit->parents; p; p = p->next) {
2425                 struct commit *parent = p->item;
2426                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2427                         parent->object.flags |= TMP_MARK;
2428                         marked++;
2429                 }
2430         }
2431
2432         return marked;
2433 }
2434
2435 /*
2436  * Awkward naming - this means one parent we are TREESAME to.
2437  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2438  * empty tree). Better name suggestions?
2439  */
2440 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2441 {
2442         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2443         struct commit *unmarked = NULL, *marked = NULL;
2444         struct commit_list *p;
2445         unsigned n;
2446
2447         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2448                 if (ts->treesame[n]) {
2449                         if (p->item->object.flags & TMP_MARK) {
2450                                 if (!marked)
2451                                         marked = p->item;
2452                         } else {
2453                                 if (!unmarked) {
2454                                         unmarked = p->item;
2455                                         break;
2456                                 }
2457                         }
2458                 }
2459         }
2460
2461         /*
2462          * If we are TREESAME to a marked-for-deletion parent, but not to any
2463          * unmarked parents, unmark the first TREESAME parent. This is the
2464          * parent that the default simplify_history==1 scan would have followed,
2465          * and it doesn't make sense to omit that path when asking for a
2466          * simplified full history. Retaining it improves the chances of
2467          * understanding odd missed merges that took an old version of a file.
2468          *
2469          * Example:
2470          *
2471          *   I--------*X       A modified the file, but mainline merge X used
2472          *    \       /        "-s ours", so took the version from I. X is
2473          *     `-*A--'         TREESAME to I and !TREESAME to A.
2474          *
2475          * Default log from X would produce "I". Without this check,
2476          * --full-history --simplify-merges would produce "I-A-X", showing
2477          * the merge commit X and that it changed A, but not making clear that
2478          * it had just taken the I version. With this check, the topology above
2479          * is retained.
2480          *
2481          * Note that it is possible that the simplification chooses a different
2482          * TREESAME parent from the default, in which case this test doesn't
2483          * activate, and we _do_ drop the default parent. Example:
2484          *
2485          *   I------X         A modified the file, but it was reverted in B,
2486          *    \    /          meaning mainline merge X is TREESAME to both
2487          *    *A-*B           parents.
2488          *
2489          * Default log would produce "I" by following the first parent;
2490          * --full-history --simplify-merges will produce "I-A-B". But this is a
2491          * reasonable result - it presents a logical full history leading from
2492          * I to X, and X is not an important merge.
2493          */
2494         if (!unmarked && marked) {
2495                 marked->object.flags &= ~TMP_MARK;
2496                 return 1;
2497         }
2498
2499         return 0;
2500 }
2501
2502 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2503 {
2504         struct commit_list **pp, *p;
2505         int nth_parent, removed = 0;
2506
2507         pp = &commit->parents;
2508         nth_parent = 0;
2509         while ((p = *pp) != NULL) {
2510                 struct commit *parent = p->item;
2511                 if (parent->object.flags & TMP_MARK) {
2512                         parent->object.flags &= ~TMP_MARK;
2513                         *pp = p->next;
2514                         free(p);
2515                         removed++;
2516                         compact_treesame(revs, commit, nth_parent);
2517                         continue;
2518                 }
2519                 pp = &p->next;
2520                 nth_parent++;
2521         }
2522
2523         /* Removing parents can only increase TREESAMEness */
2524         if (removed && !(commit->object.flags & TREESAME))
2525                 update_treesame(revs, commit);
2526
2527         return nth_parent;
2528 }
2529
2530 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2531 {
2532         struct commit_list *p;
2533         struct commit *parent;
2534         struct merge_simplify_state *st, *pst;
2535         int cnt;
2536
2537         st = locate_simplify_state(revs, commit);
2538
2539         /*
2540          * Have we handled this one?
2541          */
2542         if (st->simplified)
2543                 return tail;
2544
2545         /*
2546          * An UNINTERESTING commit simplifies to itself, so does a
2547          * root commit.  We do not rewrite parents of such commit
2548          * anyway.
2549          */
2550         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2551                 st->simplified = commit;
2552                 return tail;
2553         }
2554
2555         /*
2556          * Do we know what commit all of our parents that matter
2557          * should be rewritten to?  Otherwise we are not ready to
2558          * rewrite this one yet.
2559          */
2560         for (cnt = 0, p = commit->parents; p; p = p->next) {
2561                 pst = locate_simplify_state(revs, p->item);
2562                 if (!pst->simplified) {
2563                         tail = &commit_list_insert(p->item, tail)->next;
2564                         cnt++;
2565                 }
2566                 if (revs->first_parent_only)
2567                         break;
2568         }
2569         if (cnt) {
2570                 tail = &commit_list_insert(commit, tail)->next;
2571                 return tail;
2572         }
2573
2574         /*
2575          * Rewrite our list of parents. Note that this cannot
2576          * affect our TREESAME flags in any way - a commit is
2577          * always TREESAME to its simplification.
2578          */
2579         for (p = commit->parents; p; p = p->next) {
2580                 pst = locate_simplify_state(revs, p->item);
2581                 p->item = pst->simplified;
2582                 if (revs->first_parent_only)
2583                         break;
2584         }
2585
2586         if (revs->first_parent_only)
2587                 cnt = 1;
2588         else
2589                 cnt = remove_duplicate_parents(revs, commit);
2590
2591         /*
2592          * It is possible that we are a merge and one side branch
2593          * does not have any commit that touches the given paths;
2594          * in such a case, the immediate parent from that branch
2595          * will be rewritten to be the merge base.
2596          *
2597          *      o----X          X: the commit we are looking at;
2598          *     /    /           o: a commit that touches the paths;
2599          * ---o----'
2600          *
2601          * Further, a merge of an independent branch that doesn't
2602          * touch the path will reduce to a treesame root parent:
2603          *
2604          *  ----o----X          X: the commit we are looking at;
2605          *          /           o: a commit that touches the paths;
2606          *         r            r: a root commit not touching the paths
2607          *
2608          * Detect and simplify both cases.
2609          */
2610         if (1 < cnt) {
2611                 int marked = mark_redundant_parents(revs, commit);
2612                 marked += mark_treesame_root_parents(revs, commit);
2613                 if (marked)
2614                         marked -= leave_one_treesame_to_parent(revs, commit);
2615                 if (marked)
2616                         cnt = remove_marked_parents(revs, commit);
2617         }
2618
2619         /*
2620          * A commit simplifies to itself if it is a root, if it is
2621          * UNINTERESTING, if it touches the given paths, or if it is a
2622          * merge and its parents don't simplify to one relevant commit
2623          * (the first two cases are already handled at the beginning of
2624          * this function).
2625          *
2626          * Otherwise, it simplifies to what its sole relevant parent
2627          * simplifies to.
2628          */
2629         if (!cnt ||
2630             (commit->object.flags & UNINTERESTING) ||
2631             !(commit->object.flags & TREESAME) ||
2632             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2633                 st->simplified = commit;
2634         else {
2635                 pst = locate_simplify_state(revs, parent);
2636                 st->simplified = pst->simplified;
2637         }
2638         return tail;
2639 }
2640
2641 static void simplify_merges(struct rev_info *revs)
2642 {
2643         struct commit_list *list, *next;
2644         struct commit_list *yet_to_do, **tail;
2645         struct commit *commit;
2646
2647         if (!revs->prune)
2648                 return;
2649
2650         /* feed the list reversed */
2651         yet_to_do = NULL;
2652         for (list = revs->commits; list; list = next) {
2653                 commit = list->item;
2654                 next = list->next;
2655                 /*
2656                  * Do not free(list) here yet; the original list
2657                  * is used later in this function.
2658                  */
2659                 commit_list_insert(commit, &yet_to_do);
2660         }
2661         while (yet_to_do) {
2662                 list = yet_to_do;
2663                 yet_to_do = NULL;
2664                 tail = &yet_to_do;
2665                 while (list) {
2666                         commit = list->item;
2667                         next = list->next;
2668                         free(list);
2669                         list = next;
2670                         tail = simplify_one(revs, commit, tail);
2671                 }
2672         }
2673
2674         /* clean up the result, removing the simplified ones */
2675         list = revs->commits;
2676         revs->commits = NULL;
2677         tail = &revs->commits;
2678         while (list) {
2679                 struct merge_simplify_state *st;
2680
2681                 commit = list->item;
2682                 next = list->next;
2683                 free(list);
2684                 list = next;
2685                 st = locate_simplify_state(revs, commit);
2686                 if (st->simplified == commit)
2687                         tail = &commit_list_insert(commit, tail)->next;
2688         }
2689 }
2690
2691 static void set_children(struct rev_info *revs)
2692 {
2693         struct commit_list *l;
2694         for (l = revs->commits; l; l = l->next) {
2695                 struct commit *commit = l->item;
2696                 struct commit_list *p;
2697
2698                 for (p = commit->parents; p; p = p->next)
2699                         add_child(revs, p->item, commit);
2700         }
2701 }
2702
2703 void reset_revision_walk(void)
2704 {
2705         clear_object_flags(SEEN | ADDED | SHOWN);
2706 }
2707
2708 int prepare_revision_walk(struct rev_info *revs)
2709 {
2710         int i;
2711         struct object_array old_pending;
2712         struct commit_list **next = &revs->commits;
2713
2714         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
2715         revs->pending.nr = 0;
2716         revs->pending.alloc = 0;
2717         revs->pending.objects = NULL;
2718         for (i = 0; i < old_pending.nr; i++) {
2719                 struct object_array_entry *e = old_pending.objects + i;
2720                 struct commit *commit = handle_commit(revs, e);
2721                 if (commit) {
2722                         if (!(commit->object.flags & SEEN)) {
2723                                 commit->object.flags |= SEEN;
2724                                 next = commit_list_append(commit, next);
2725                         }
2726                 }
2727         }
2728         if (!revs->leak_pending)
2729                 object_array_clear(&old_pending);
2730
2731         /* Signal whether we need per-parent treesame decoration */
2732         if (revs->simplify_merges ||
2733             (revs->limited && limiting_can_increase_treesame(revs)))
2734                 revs->treesame.name = "treesame";
2735
2736         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2737                 commit_list_sort_by_date(&revs->commits);
2738         if (revs->no_walk)
2739                 return 0;
2740         if (revs->limited)
2741                 if (limit_list(revs) < 0)
2742                         return -1;
2743         if (revs->topo_order)
2744                 sort_in_topological_order(&revs->commits, revs->sort_order);
2745         if (revs->line_level_traverse)
2746                 line_log_filter(revs);
2747         if (revs->simplify_merges)
2748                 simplify_merges(revs);
2749         if (revs->children.name)
2750                 set_children(revs);
2751         return 0;
2752 }
2753
2754 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2755 {
2756         struct commit_list *cache = NULL;
2757
2758         for (;;) {
2759                 struct commit *p = *pp;
2760                 if (!revs->limited)
2761                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2762                                 return rewrite_one_error;
2763                 if (p->object.flags & UNINTERESTING)
2764                         return rewrite_one_ok;
2765                 if (!(p->object.flags & TREESAME))
2766                         return rewrite_one_ok;
2767                 if (!p->parents)
2768                         return rewrite_one_noparents;
2769                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2770                         return rewrite_one_ok;
2771                 *pp = p;
2772         }
2773 }
2774
2775 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2776         rewrite_parent_fn_t rewrite_parent)
2777 {
2778         struct commit_list **pp = &commit->parents;
2779         while (*pp) {
2780                 struct commit_list *parent = *pp;
2781                 switch (rewrite_parent(revs, &parent->item)) {
2782                 case rewrite_one_ok:
2783                         break;
2784                 case rewrite_one_noparents:
2785                         *pp = parent->next;
2786                         continue;
2787                 case rewrite_one_error:
2788                         return -1;
2789                 }
2790                 pp = &parent->next;
2791         }
2792         remove_duplicate_parents(revs, commit);
2793         return 0;
2794 }
2795
2796 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2797 {
2798         char *person, *endp;
2799         size_t len, namelen, maillen;
2800         const char *name;
2801         const char *mail;
2802         struct ident_split ident;
2803
2804         person = strstr(buf->buf, what);
2805         if (!person)
2806                 return 0;
2807
2808         person += strlen(what);
2809         endp = strchr(person, '\n');
2810         if (!endp)
2811                 return 0;
2812
2813         len = endp - person;
2814
2815         if (split_ident_line(&ident, person, len))
2816                 return 0;
2817
2818         mail = ident.mail_begin;
2819         maillen = ident.mail_end - ident.mail_begin;
2820         name = ident.name_begin;
2821         namelen = ident.name_end - ident.name_begin;
2822
2823         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
2824                 struct strbuf namemail = STRBUF_INIT;
2825
2826                 strbuf_addf(&namemail, "%.*s <%.*s>",
2827                             (int)namelen, name, (int)maillen, mail);
2828
2829                 strbuf_splice(buf, ident.name_begin - buf->buf,
2830                               ident.mail_end - ident.name_begin + 1,
2831                               namemail.buf, namemail.len);
2832
2833                 strbuf_release(&namemail);
2834
2835                 return 1;
2836         }
2837
2838         return 0;
2839 }
2840
2841 static int commit_match(struct commit *commit, struct rev_info *opt)
2842 {
2843         int retval;
2844         const char *encoding;
2845         const char *message;
2846         struct strbuf buf = STRBUF_INIT;
2847
2848         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2849                 return 1;
2850
2851         /* Prepend "fake" headers as needed */
2852         if (opt->grep_filter.use_reflog_filter) {
2853                 strbuf_addstr(&buf, "reflog ");
2854                 get_reflog_message(&buf, opt->reflog_info);
2855                 strbuf_addch(&buf, '\n');
2856         }
2857
2858         /*
2859          * We grep in the user's output encoding, under the assumption that it
2860          * is the encoding they are most likely to write their grep pattern
2861          * for. In addition, it means we will match the "notes" encoding below,
2862          * so we will not end up with a buffer that has two different encodings
2863          * in it.
2864          */
2865         encoding = get_log_output_encoding();
2866         message = logmsg_reencode(commit, NULL, encoding);
2867
2868         /* Copy the commit to temporary if we are using "fake" headers */
2869         if (buf.len)
2870                 strbuf_addstr(&buf, message);
2871
2872         if (opt->grep_filter.header_list && opt->mailmap) {
2873                 if (!buf.len)
2874                         strbuf_addstr(&buf, message);
2875
2876                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
2877                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
2878         }
2879
2880         /* Append "fake" message parts as needed */
2881         if (opt->show_notes) {
2882                 if (!buf.len)
2883                         strbuf_addstr(&buf, message);
2884                 format_display_notes(commit->object.sha1, &buf, encoding, 1);
2885         }
2886
2887         /*
2888          * Find either in the original commit message, or in the temporary.
2889          * Note that we cast away the constness of "message" here. It is
2890          * const because it may come from the cached commit buffer. That's OK,
2891          * because we know that it is modifiable heap memory, and that while
2892          * grep_buffer may modify it for speed, it will restore any
2893          * changes before returning.
2894          */
2895         if (buf.len)
2896                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
2897         else
2898                 retval = grep_buffer(&opt->grep_filter,
2899                                      (char *)message, strlen(message));
2900         strbuf_release(&buf);
2901         unuse_commit_buffer(commit, message);
2902         return opt->invert_grep ? !retval : retval;
2903 }
2904
2905 static inline int want_ancestry(const struct rev_info *revs)
2906 {
2907         return (revs->rewrite_parents || revs->children.name);
2908 }
2909
2910 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2911 {
2912         if (commit->object.flags & SHOWN)
2913                 return commit_ignore;
2914         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2915                 return commit_ignore;
2916         if (revs->show_all)
2917                 return commit_show;
2918         if (commit->object.flags & UNINTERESTING)
2919                 return commit_ignore;
2920         if (revs->min_age != -1 && (commit->date > revs->min_age))
2921                 return commit_ignore;
2922         if (revs->min_parents || (revs->max_parents >= 0)) {
2923                 int n = commit_list_count(commit->parents);
2924                 if ((n < revs->min_parents) ||
2925                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2926                         return commit_ignore;
2927         }
2928         if (!commit_match(commit, revs))
2929                 return commit_ignore;
2930         if (revs->prune && revs->dense) {
2931                 /* Commit without changes? */
2932                 if (commit->object.flags & TREESAME) {
2933                         int n;
2934                         struct commit_list *p;
2935                         /* drop merges unless we want parenthood */
2936                         if (!want_ancestry(revs))
2937                                 return commit_ignore;
2938                         /*
2939                          * If we want ancestry, then need to keep any merges
2940                          * between relevant commits to tie together topology.
2941                          * For consistency with TREESAME and simplification
2942                          * use "relevant" here rather than just INTERESTING,
2943                          * to treat bottom commit(s) as part of the topology.
2944                          */
2945                         for (n = 0, p = commit->parents; p; p = p->next)
2946                                 if (relevant_commit(p->item))
2947                                         if (++n >= 2)
2948                                                 return commit_show;
2949                         return commit_ignore;
2950                 }
2951         }
2952         return commit_show;
2953 }
2954
2955 define_commit_slab(saved_parents, struct commit_list *);
2956
2957 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
2958
2959 /*
2960  * You may only call save_parents() once per commit (this is checked
2961  * for non-root commits).
2962  */
2963 static void save_parents(struct rev_info *revs, struct commit *commit)
2964 {
2965         struct commit_list **pp;
2966
2967         if (!revs->saved_parents_slab) {
2968                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
2969                 init_saved_parents(revs->saved_parents_slab);
2970         }
2971
2972         pp = saved_parents_at(revs->saved_parents_slab, commit);
2973
2974         /*
2975          * When walking with reflogs, we may visit the same commit
2976          * several times: once for each appearance in the reflog.
2977          *
2978          * In this case, save_parents() will be called multiple times.
2979          * We want to keep only the first set of parents.  We need to
2980          * store a sentinel value for an empty (i.e., NULL) parent
2981          * list to distinguish it from a not-yet-saved list, however.
2982          */
2983         if (*pp)
2984                 return;
2985         if (commit->parents)
2986                 *pp = copy_commit_list(commit->parents);
2987         else
2988                 *pp = EMPTY_PARENT_LIST;
2989 }
2990
2991 static void free_saved_parents(struct rev_info *revs)
2992 {
2993         if (revs->saved_parents_slab)
2994                 clear_saved_parents(revs->saved_parents_slab);
2995 }
2996
2997 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
2998 {
2999         struct commit_list *parents;
3000
3001         if (!revs->saved_parents_slab)
3002                 return commit->parents;
3003
3004         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3005         if (parents == EMPTY_PARENT_LIST)
3006                 return NULL;
3007         return parents;
3008 }
3009
3010 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3011 {
3012         enum commit_action action = get_commit_action(revs, commit);
3013
3014         if (action == commit_show &&
3015             !revs->show_all &&
3016             revs->prune && revs->dense && want_ancestry(revs)) {
3017                 /*
3018                  * --full-diff on simplified parents is no good: it
3019                  * will show spurious changes from the commits that
3020                  * were elided.  So we save the parents on the side
3021                  * when --full-diff is in effect.
3022                  */
3023                 if (revs->full_diff)
3024                         save_parents(revs, commit);
3025                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3026                         return commit_error;
3027         }
3028         return action;
3029 }
3030
3031 static void track_linear(struct rev_info *revs, struct commit *commit)
3032 {
3033         if (revs->track_first_time) {
3034                 revs->linear = 1;
3035                 revs->track_first_time = 0;
3036         } else {
3037                 struct commit_list *p;
3038                 for (p = revs->previous_parents; p; p = p->next)
3039                         if (p->item == NULL || /* first commit */
3040                             !hashcmp(p->item->object.sha1, commit->object.sha1))
3041                                 break;
3042                 revs->linear = p != NULL;
3043         }
3044         if (revs->reverse) {
3045                 if (revs->linear)
3046                         commit->object.flags |= TRACK_LINEAR;
3047         }
3048         free_commit_list(revs->previous_parents);
3049         revs->previous_parents = copy_commit_list(commit->parents);
3050 }
3051
3052 static struct commit *get_revision_1(struct rev_info *revs)
3053 {
3054         if (!revs->commits)
3055                 return NULL;
3056
3057         do {
3058                 struct commit_list *entry = revs->commits;
3059                 struct commit *commit = entry->item;
3060
3061                 revs->commits = entry->next;
3062                 free(entry);
3063
3064                 if (revs->reflog_info) {
3065                         save_parents(revs, commit);
3066                         fake_reflog_parent(revs->reflog_info, commit);
3067                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3068                 }
3069
3070                 /*
3071                  * If we haven't done the list limiting, we need to look at
3072                  * the parents here. We also need to do the date-based limiting
3073                  * that we'd otherwise have done in limit_list().
3074                  */
3075                 if (!revs->limited) {
3076                         if (revs->max_age != -1 &&
3077                             (commit->date < revs->max_age))
3078                                 continue;
3079                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) {
3080                                 if (!revs->ignore_missing_links)
3081                                         die("Failed to traverse parents of commit %s",
3082                                                 sha1_to_hex(commit->object.sha1));
3083                         }
3084                 }
3085
3086                 switch (simplify_commit(revs, commit)) {
3087                 case commit_ignore:
3088                         continue;
3089                 case commit_error:
3090                         die("Failed to simplify parents of commit %s",
3091                             sha1_to_hex(commit->object.sha1));
3092                 default:
3093                         if (revs->track_linear)
3094                                 track_linear(revs, commit);
3095                         return commit;
3096                 }
3097         } while (revs->commits);
3098         return NULL;
3099 }
3100
3101 /*
3102  * Return true for entries that have not yet been shown.  (This is an
3103  * object_array_each_func_t.)
3104  */
3105 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3106 {
3107         return !(entry->item->flags & SHOWN);
3108 }
3109
3110 /*
3111  * If array is on the verge of a realloc, garbage-collect any entries
3112  * that have already been shown to try to free up some space.
3113  */
3114 static void gc_boundary(struct object_array *array)
3115 {
3116         if (array->nr == array->alloc)
3117                 object_array_filter(array, entry_unshown, NULL);
3118 }
3119
3120 static void create_boundary_commit_list(struct rev_info *revs)
3121 {
3122         unsigned i;
3123         struct commit *c;
3124         struct object_array *array = &revs->boundary_commits;
3125         struct object_array_entry *objects = array->objects;
3126
3127         /*
3128          * If revs->commits is non-NULL at this point, an error occurred in
3129          * get_revision_1().  Ignore the error and continue printing the
3130          * boundary commits anyway.  (This is what the code has always
3131          * done.)
3132          */
3133         if (revs->commits) {
3134                 free_commit_list(revs->commits);
3135                 revs->commits = NULL;
3136         }
3137
3138         /*
3139          * Put all of the actual boundary commits from revs->boundary_commits
3140          * into revs->commits
3141          */
3142         for (i = 0; i < array->nr; i++) {
3143                 c = (struct commit *)(objects[i].item);
3144                 if (!c)
3145                         continue;
3146                 if (!(c->object.flags & CHILD_SHOWN))
3147                         continue;
3148                 if (c->object.flags & (SHOWN | BOUNDARY))
3149                         continue;
3150                 c->object.flags |= BOUNDARY;
3151                 commit_list_insert(c, &revs->commits);
3152         }
3153
3154         /*
3155          * If revs->topo_order is set, sort the boundary commits
3156          * in topological order
3157          */
3158         sort_in_topological_order(&revs->commits, revs->sort_order);
3159 }
3160
3161 static struct commit *get_revision_internal(struct rev_info *revs)
3162 {
3163         struct commit *c = NULL;
3164         struct commit_list *l;
3165
3166         if (revs->boundary == 2) {
3167                 /*
3168                  * All of the normal commits have already been returned,
3169                  * and we are now returning boundary commits.
3170                  * create_boundary_commit_list() has populated
3171                  * revs->commits with the remaining commits to return.
3172                  */
3173                 c = pop_commit(&revs->commits);
3174                 if (c)
3175                         c->object.flags |= SHOWN;
3176                 return c;
3177         }
3178
3179         /*
3180          * If our max_count counter has reached zero, then we are done. We
3181          * don't simply return NULL because we still might need to show
3182          * boundary commits. But we want to avoid calling get_revision_1, which
3183          * might do a considerable amount of work finding the next commit only
3184          * for us to throw it away.
3185          *
3186          * If it is non-zero, then either we don't have a max_count at all
3187          * (-1), or it is still counting, in which case we decrement.
3188          */
3189         if (revs->max_count) {
3190                 c = get_revision_1(revs);
3191                 if (c) {
3192                         while (revs->skip_count > 0) {
3193                                 revs->skip_count--;
3194                                 c = get_revision_1(revs);
3195                                 if (!c)
3196                                         break;
3197                         }
3198                 }
3199
3200                 if (revs->max_count > 0)
3201                         revs->max_count--;
3202         }
3203
3204         if (c)
3205                 c->object.flags |= SHOWN;
3206
3207         if (!revs->boundary)
3208                 return c;
3209
3210         if (!c) {
3211                 /*
3212                  * get_revision_1() runs out the commits, and
3213                  * we are done computing the boundaries.
3214                  * switch to boundary commits output mode.
3215                  */
3216                 revs->boundary = 2;
3217
3218                 /*
3219                  * Update revs->commits to contain the list of
3220                  * boundary commits.
3221                  */
3222                 create_boundary_commit_list(revs);
3223
3224                 return get_revision_internal(revs);
3225         }
3226
3227         /*
3228          * boundary commits are the commits that are parents of the
3229          * ones we got from get_revision_1() but they themselves are
3230          * not returned from get_revision_1().  Before returning
3231          * 'c', we need to mark its parents that they could be boundaries.
3232          */
3233
3234         for (l = c->parents; l; l = l->next) {
3235                 struct object *p;
3236                 p = &(l->item->object);
3237                 if (p->flags & (CHILD_SHOWN | SHOWN))
3238                         continue;
3239                 p->flags |= CHILD_SHOWN;
3240                 gc_boundary(&revs->boundary_commits);
3241                 add_object_array(p, NULL, &revs->boundary_commits);
3242         }
3243
3244         return c;
3245 }
3246
3247 struct commit *get_revision(struct rev_info *revs)
3248 {
3249         struct commit *c;
3250         struct commit_list *reversed;
3251
3252         if (revs->reverse) {
3253                 reversed = NULL;
3254                 while ((c = get_revision_internal(revs)))
3255                         commit_list_insert(c, &reversed);
3256                 revs->commits = reversed;
3257                 revs->reverse = 0;
3258                 revs->reverse_output_stage = 1;
3259         }
3260
3261         if (revs->reverse_output_stage) {
3262                 c = pop_commit(&revs->commits);
3263                 if (revs->track_linear)
3264                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3265                 return c;
3266         }
3267
3268         c = get_revision_internal(revs);
3269         if (c && revs->graph)
3270                 graph_update(revs->graph, c);
3271         if (!c) {
3272                 free_saved_parents(revs);
3273                 if (revs->previous_parents) {
3274                         free_commit_list(revs->previous_parents);
3275                         revs->previous_parents = NULL;
3276                 }
3277         }
3278         return c;
3279 }
3280
3281 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3282 {
3283         if (commit->object.flags & BOUNDARY)
3284                 return "-";
3285         else if (commit->object.flags & UNINTERESTING)
3286                 return "^";
3287         else if (commit->object.flags & PATCHSAME)
3288                 return "=";
3289         else if (!revs || revs->left_right) {
3290                 if (commit->object.flags & SYMMETRIC_LEFT)
3291                         return "<";
3292                 else
3293                         return ">";
3294         } else if (revs->graph)
3295                 return "*";
3296         else if (revs->cherry_mark)
3297                 return "+";
3298         return "";
3299 }
3300
3301 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3302 {
3303         char *mark = get_revision_mark(revs, commit);
3304         if (!strlen(mark))
3305                 return;
3306         fputs(mark, stdout);
3307         putchar(' ');
3308 }