Pileus Git - ~andy/git/blob - revision.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "refs.h"
   8 #include "revision.h"
   9 #include "graph.h"
  10 #include "grep.h"
  11 #include "reflog-walk.h"
  12 #include "patch-ids.h"
  13 #include "decorate.h"
  14 #include "log-tree.h"
  15 #include "string-list.h"
  16
  17 volatile show_early_output_fn_t show_early_output;
  18
  19 char *path_name(const struct name_path *path, const char *name)
  20 {
  21         const struct name_path *p;
  22         char *n, *m;
  23         int nlen = strlen(name);
  24         int len = nlen + 1;
  25
  26         for (p = path; p; p = p->up) {
  27                 if (p->elem_len)
  28                         len += p->elem_len + 1;
  29         }
  30         n = xmalloc(len);
  31         m = n + len - (nlen + 1);
  32         strcpy(m, name);
  33         for (p = path; p; p = p->up) {
  34                 if (p->elem_len) {
  35                         m -= p->elem_len + 1;
  36                         memcpy(m, p->elem, p->elem_len);
  37                         m[p->elem_len] = '/';
  38                 }
  39         }
  40         return n;
  41 }
  42
  43 void add_object(struct object *obj,
  44                 struct object_array *p,
  45                 struct name_path *path,
  46                 const char *name)
  47 {
  48         add_object_array(obj, path_name(path, name), p);
  49 }
  50
  51 static void mark_blob_uninteresting(struct blob *blob)
  52 {
  53         if (!blob)
  54                 return;
  55         if (blob->object.flags & UNINTERESTING)
  56                 return;
  57         blob->object.flags |= UNINTERESTING;
  58 }
  59
  60 void mark_tree_uninteresting(struct tree *tree)
  61 {
  62         struct tree_desc desc;
  63         struct name_entry entry;
  64         struct object *obj = &tree->object;
  65
  66         if (!tree)
  67                 return;
  68         if (obj->flags & UNINTERESTING)
  69                 return;
  70         obj->flags |= UNINTERESTING;
  71         if (!has_sha1_file(obj->sha1))
  72                 return;
  73         if (parse_tree(tree) < 0)
  74                 die("bad tree %s", sha1_to_hex(obj->sha1));
  75
  76         init_tree_desc(&desc, tree->buffer, tree->size);
  77         while (tree_entry(&desc, &entry)) {
  78                 switch (object_type(entry.mode)) {
  79                 case OBJ_TREE:
  80                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  81                         break;
  82                 case OBJ_BLOB:
  83                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  84                         break;
  85                 default:
  86                         /* Subproject commit - not in this repository */
  87                         break;
  88                 }
  89         }
  90
  91         /*
  92          * We don't care about the tree any more
  93          * after it has been marked uninteresting.
  94          */
  95         free(tree->buffer);
  96         tree->buffer = NULL;
  97 }
  98
  99 void mark_parents_uninteresting(struct commit *commit)
 100 {
 101         struct commit_list *parents = commit->parents;
 102
 103         while (parents) {
 104                 struct commit *commit = parents->item;
 105                 if (!(commit->object.flags & UNINTERESTING)) {
 106                         commit->object.flags |= UNINTERESTING;
 107
 108                         /*
 109                          * Normally we haven't parsed the parent
 110                          * yet, so we won't have a parent of a parent
 111                          * here. However, it may turn out that we've
 112                          * reached this commit some other way (where it
 113                          * wasn't uninteresting), in which case we need
 114                          * to mark its parents recursively too..
 115                          */
 116                         if (commit->parents)
 117                                 mark_parents_uninteresting(commit);
 118                 }
 119
 120                 /*
 121                  * A missing commit is ok iff its parent is marked
 122                  * uninteresting.
 123                  *
 124                  * We just mark such a thing parsed, so that when
 125                  * it is popped next time around, we won't be trying
 126                  * to parse it and get an error.
 127                  */
 128                 if (!has_sha1_file(commit->object.sha1))
 129                         commit->object.parsed = 1;
 130                 parents = parents->next;
 131         }
 132 }
 133
 134 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 135 {
 136         if (revs->no_walk && (obj->flags & UNINTERESTING))
 137                 revs->no_walk = 0;
 138         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 139                 struct strbuf buf = STRBUF_INIT;
 140                 int len = interpret_branch_name(name, &buf);
 141                 int st;
 142
 143                 if (0 < len && name[len] && buf.len)
 144                         strbuf_addstr(&buf, name + len);
 145                 st = add_reflog_for_walk(revs->reflog_info,
 146                                          (struct commit *)obj,
 147                                          buf.buf[0] ? buf.buf: name);
 148                 strbuf_release(&buf);
 149                 if (st)
 150                         return;
 151         }
 152         add_object_array_with_mode(obj, name, &revs->pending, mode);
 153 }
 154
 155 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 156 {
 157         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 158 }
 159
 160 void add_head_to_pending(struct rev_info *revs)
 161 {
 162         unsigned char sha1[20];
 163         struct object *obj;
 164         if (get_sha1("HEAD", sha1))
 165                 return;
 166         obj = parse_object(sha1);
 167         if (!obj)
 168                 return;
 169         add_pending_object(revs, obj, "HEAD");
 170 }
 171
 172 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 173 {
 174         struct object *object;
 175
 176         object = parse_object(sha1);
 177         if (!object)
 178                 die("bad object %s", name);
 179         object->flags |= flags;
 180         return object;
 181 }
 182
 183 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 184 {
 185         unsigned long flags = object->flags;
 186
 187         /*
 188          * Tag object? Look what it points to..
 189          */
 190         while (object->type == OBJ_TAG) {
 191                 struct tag *tag = (struct tag *) object;
 192                 if (revs->tag_objects && !(flags & UNINTERESTING))
 193                         add_pending_object(revs, object, tag->tag);
 194                 if (!tag->tagged)
 195                         die("bad tag");
 196                 object = parse_object(tag->tagged->sha1);
 197                 if (!object) {
 198                         if (flags & UNINTERESTING)
 199                                 return NULL;
 200                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 201                 }
 202         }
 203
 204         /*
 205          * Commit object? Just return it, we'll do all the complex
 206          * reachability crud.
 207          */
 208         if (object->type == OBJ_COMMIT) {
 209                 struct commit *commit = (struct commit *)object;
 210                 if (parse_commit(commit) < 0)
 211                         die("unable to parse commit %s", name);
 212                 if (flags & UNINTERESTING) {
 213                         commit->object.flags |= UNINTERESTING;
 214                         mark_parents_uninteresting(commit);
 215                         revs->limited = 1;
 216                 }
 217                 if (revs->show_source && !commit->util)
 218                         commit->util = (void *) name;
 219                 return commit;
 220         }
 221
 222         /*
 223          * Tree object? Either mark it uninteresting, or add it
 224          * to the list of objects to look at later..
 225          */
 226         if (object->type == OBJ_TREE) {
 227                 struct tree *tree = (struct tree *)object;
 228                 if (!revs->tree_objects)
 229                         return NULL;
 230                 if (flags & UNINTERESTING) {
 231                         mark_tree_uninteresting(tree);
 232                         return NULL;
 233                 }
 234                 add_pending_object(revs, object, "");
 235                 return NULL;
 236         }
 237
 238         /*
 239          * Blob object? You know the drill by now..
 240          */
 241         if (object->type == OBJ_BLOB) {
 242                 struct blob *blob = (struct blob *)object;
 243                 if (!revs->blob_objects)
 244                         return NULL;
 245                 if (flags & UNINTERESTING) {
 246                         mark_blob_uninteresting(blob);
 247                         return NULL;
 248                 }
 249                 add_pending_object(revs, object, "");
 250                 return NULL;
 251         }
 252         die("%s is unknown object", name);
 253 }
 254
 255 static int everybody_uninteresting(struct commit_list *orig)
 256 {
 257         struct commit_list *list = orig;
 258         while (list) {
 259                 struct commit *commit = list->item;
 260                 list = list->next;
 261                 if (commit->object.flags & UNINTERESTING)
 262                         continue;
 263                 return 0;
 264         }
 265         return 1;
 266 }
 267
 268 /*
 269  * The goal is to get REV_TREE_NEW as the result only if the
 270  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 271  * if the whole diff is removal of old data, and otherwise
 272  * REV_TREE_DIFFERENT (of course if the trees are the same we
 273  * want REV_TREE_SAME).
 274  * That means that once we get to REV_TREE_DIFFERENT, we do not
 275  * have to look any further.
 276  */
 277 static int tree_difference = REV_TREE_SAME;
 278
 279 static void file_add_remove(struct diff_options *options,
 280                     int addremove, unsigned mode,
 281                     const unsigned char *sha1,
 282                     const char *fullpath, unsigned dirty_submodule)
 283 {
 284         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 285
 286         tree_difference |= diff;
 287         if (tree_difference == REV_TREE_DIFFERENT)
 288                 DIFF_OPT_SET(options, HAS_CHANGES);
 289 }
 290
 291 static void file_change(struct diff_options *options,
 292                  unsigned old_mode, unsigned new_mode,
 293                  const unsigned char *old_sha1,
 294                  const unsigned char *new_sha1,
 295                  const char *fullpath,
 296                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 297 {
 298         tree_difference = REV_TREE_DIFFERENT;
 299         DIFF_OPT_SET(options, HAS_CHANGES);
 300 }
 301
 302 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 303 {
 304         struct tree *t1 = parent->tree;
 305         struct tree *t2 = commit->tree;
 306
 307         if (!t1)
 308                 return REV_TREE_NEW;
 309         if (!t2)
 310                 return REV_TREE_OLD;
 311
 312         if (revs->simplify_by_decoration) {
 313                 /*
 314                  * If we are simplifying by decoration, then the commit
 315                  * is worth showing if it has a tag pointing at it.
 316                  */
 317                 if (lookup_decoration(&name_decoration, &commit->object))
 318                         return REV_TREE_DIFFERENT;
 319                 /*
 320                  * A commit that is not pointed by a tag is uninteresting
 321                  * if we are not limited by path.  This means that you will
 322                  * see the usual "commits that touch the paths" plus any
 323                  * tagged commit by specifying both --simplify-by-decoration
 324                  * and pathspec.
 325                  */
 326                 if (!revs->prune_data)
 327                         return REV_TREE_SAME;
 328         }
 329
 330         tree_difference = REV_TREE_SAME;
 331         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 332         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 333                            &revs->pruning) < 0)
 334                 return REV_TREE_DIFFERENT;
 335         return tree_difference;
 336 }
 337
 338 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 339 {
 340         int retval;
 341         void *tree;
 342         unsigned long size;
 343         struct tree_desc empty, real;
 344         struct tree *t1 = commit->tree;
 345
 346         if (!t1)
 347                 return 0;
 348
 349         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 350         if (!tree)
 351                 return 0;
 352         init_tree_desc(&real, tree, size);
 353         init_tree_desc(&empty, "", 0);
 354
 355         tree_difference = REV_TREE_SAME;
 356         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 357         retval = diff_tree(&empty, &real, "", &revs->pruning);
 358         free(tree);
 359
 360         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 361 }
 362
 363 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 364 {
 365         struct commit_list **pp, *parent;
 366         int tree_changed = 0, tree_same = 0;
 367
 368         /*
 369          * If we don't do pruning, everything is interesting
 370          */
 371         if (!revs->prune)
 372                 return;
 373
 374         if (!commit->tree)
 375                 return;
 376
 377         if (!commit->parents) {
 378                 if (rev_same_tree_as_empty(revs, commit))
 379                         commit->object.flags |= TREESAME;
 380                 return;
 381         }
 382
 383         /*
 384          * Normal non-merge commit? If we don't want to make the
 385          * history dense, we consider it always to be a change..
 386          */
 387         if (!revs->dense && !commit->parents->next)
 388                 return;
 389
 390         pp = &commit->parents;
 391         while ((parent = *pp) != NULL) {
 392                 struct commit *p = parent->item;
 393
 394                 if (parse_commit(p) < 0)
 395                         die("cannot simplify commit %s (because of %s)",
 396                             sha1_to_hex(commit->object.sha1),
 397                             sha1_to_hex(p->object.sha1));
 398                 switch (rev_compare_tree(revs, p, commit)) {
 399                 case REV_TREE_SAME:
 400                         tree_same = 1;
 401                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 402                                 /* Even if a merge with an uninteresting
 403                                  * side branch brought the entire change
 404                                  * we are interested in, we do not want
 405                                  * to lose the other branches of this
 406                                  * merge, so we just keep going.
 407                                  */
 408                                 pp = &parent->next;
 409                                 continue;
 410                         }
 411                         parent->next = NULL;
 412                         commit->parents = parent;
 413                         commit->object.flags |= TREESAME;
 414                         return;
 415
 416                 case REV_TREE_NEW:
 417                         if (revs->remove_empty_trees &&
 418                             rev_same_tree_as_empty(revs, p)) {
 419                                 /* We are adding all the specified
 420                                  * paths from this parent, so the
 421                                  * history beyond this parent is not
 422                                  * interesting.  Remove its parents
 423                                  * (they are grandparents for us).
 424                                  * IOW, we pretend this parent is a
 425                                  * "root" commit.
 426                                  */
 427                                 if (parse_commit(p) < 0)
 428                                         die("cannot simplify commit %s (invalid %s)",
 429                                             sha1_to_hex(commit->object.sha1),
 430                                             sha1_to_hex(p->object.sha1));
 431                                 p->parents = NULL;
 432                         }
 433                 /* fallthrough */
 434                 case REV_TREE_OLD:
 435                 case REV_TREE_DIFFERENT:
 436                         tree_changed = 1;
 437                         pp = &parent->next;
 438                         continue;
 439                 }
 440                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 441         }
 442         if (tree_changed && !tree_same)
 443                 return;
 444         commit->object.flags |= TREESAME;
 445 }
 446
 447 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
 448                     struct commit_list *cached_base, struct commit_list **cache)
 449 {
 450         struct commit_list *new_entry;
 451
 452         if (cached_base && p->date < cached_base->item->date)
 453                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
 454         else
 455                 new_entry = commit_list_insert_by_date(p, head);
 456
 457         if (cache && (!*cache || p->date < (*cache)->item->date))
 458                 *cache = new_entry;
 459 }
 460
 461 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 462                     struct commit_list **list, struct commit_list **cache_ptr)
 463 {
 464         struct commit_list *parent = commit->parents;
 465         unsigned left_flag;
 466         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 467
 468         if (commit->object.flags & ADDED)
 469                 return 0;
 470         commit->object.flags |= ADDED;
 471
 472         /*
 473          * If the commit is uninteresting, don't try to
 474          * prune parents - we want the maximal uninteresting
 475          * set.
 476          *
 477          * Normally we haven't parsed the parent
 478          * yet, so we won't have a parent of a parent
 479          * here. However, it may turn out that we've
 480          * reached this commit some other way (where it
 481          * wasn't uninteresting), in which case we need
 482          * to mark its parents recursively too..
 483          */
 484         if (commit->object.flags & UNINTERESTING) {
 485                 while (parent) {
 486                         struct commit *p = parent->item;
 487                         parent = parent->next;
 488                         if (p)
 489                                 p->object.flags |= UNINTERESTING;
 490                         if (parse_commit(p) < 0)
 491                                 continue;
 492                         if (p->parents)
 493                                 mark_parents_uninteresting(p);
 494                         if (p->object.flags & SEEN)
 495                                 continue;
 496                         p->object.flags |= SEEN;
 497                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 498                 }
 499                 return 0;
 500         }
 501
 502         /*
 503          * Ok, the commit wasn't uninteresting. Try to
 504          * simplify the commit history and find the parent
 505          * that has no differences in the path set if one exists.
 506          */
 507         try_to_simplify_commit(revs, commit);
 508
 509         if (revs->no_walk)
 510                 return 0;
 511
 512         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 513
 514         for (parent = commit->parents; parent; parent = parent->next) {
 515                 struct commit *p = parent->item;
 516
 517                 if (parse_commit(p) < 0)
 518                         return -1;
 519                 if (revs->show_source && !p->util)
 520                         p->util = commit->util;
 521                 p->object.flags |= left_flag;
 522                 if (!(p->object.flags & SEEN)) {
 523                         p->object.flags |= SEEN;
 524                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 525                 }
 526                 if (revs->first_parent_only)
 527                         break;
 528         }
 529         return 0;
 530 }
 531
 532 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 533 {
 534         struct commit_list *p;
 535         int left_count = 0, right_count = 0;
 536         int left_first;
 537         struct patch_ids ids;
 538         unsigned cherry_flag;
 539
 540         /* First count the commits on the left and on the right */
 541         for (p = list; p; p = p->next) {
 542                 struct commit *commit = p->item;
 543                 unsigned flags = commit->object.flags;
 544                 if (flags & BOUNDARY)
 545                         ;
 546                 else if (flags & SYMMETRIC_LEFT)
 547                         left_count++;
 548                 else
 549                         right_count++;
 550         }
 551
 552         if (!left_count || !right_count)
 553                 return;
 554
 555         left_first = left_count < right_count;
 556         init_patch_ids(&ids);
 557         if (revs->diffopt.nr_paths) {
 558                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 559                 ids.diffopts.paths = revs->diffopt.paths;
 560                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 561         }
 562
 563         /* Compute patch-ids for one side */
 564         for (p = list; p; p = p->next) {
 565                 struct commit *commit = p->item;
 566                 unsigned flags = commit->object.flags;
 567
 568                 if (flags & BOUNDARY)
 569                         continue;
 570                 /*
 571                  * If we have fewer left, left_first is set and we omit
 572                  * commits on the right branch in this loop.  If we have
 573                  * fewer right, we skip the left ones.
 574                  */
 575                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 576                         continue;
 577                 commit->util = add_commit_patch_id(commit, &ids);
 578         }
 579
 580         /* either cherry_mark or cherry_pick are true */
 581         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
 582
 583         /* Check the other side */
 584         for (p = list; p; p = p->next) {
 585                 struct commit *commit = p->item;
 586                 struct patch_id *id;
 587                 unsigned flags = commit->object.flags;
 588
 589                 if (flags & BOUNDARY)
 590                         continue;
 591                 /*
 592                  * If we have fewer left, left_first is set and we omit
 593                  * commits on the left branch in this loop.
 594                  */
 595                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 596                         continue;
 597
 598                 /*
 599                  * Have we seen the same patch id?
 600                  */
 601                 id = has_commit_patch_id(commit, &ids);
 602                 if (!id)
 603                         continue;
 604                 id->seen = 1;
 605                 commit->object.flags |= cherry_flag;
 606         }
 607
 608         /* Now check the original side for seen ones */
 609         for (p = list; p; p = p->next) {
 610                 struct commit *commit = p->item;
 611                 struct patch_id *ent;
 612
 613                 ent = commit->util;
 614                 if (!ent)
 615                         continue;
 616                 if (ent->seen)
 617                         commit->object.flags |= cherry_flag;
 618                 commit->util = NULL;
 619         }
 620
 621         free_patch_ids(&ids);
 622 }
 623
 624 /* How many extra uninteresting commits we want to see.. */
 625 #define SLOP 5
 626
 627 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 628 {
 629         /*
 630          * No source list at all? We're definitely done..
 631          */
 632         if (!src)
 633                 return 0;
 634
 635         /*
 636          * Does the destination list contain entries with a date
 637          * before the source list? Definitely _not_ done.
 638          */
 639         if (date < src->item->date)
 640                 return SLOP;
 641
 642         /*
 643          * Does the source list still have interesting commits in
 644          * it? Definitely not done..
 645          */
 646         if (!everybody_uninteresting(src))
 647                 return SLOP;
 648
 649         /* Ok, we're closing in.. */
 650         return slop-1;
 651 }
 652
 653 /*
 654  * "rev-list --ancestry-path A..B" computes commits that are ancestors
 655  * of B but not ancestors of A but further limits the result to those
 656  * that are descendants of A.  This takes the list of bottom commits and
 657  * the result of "A..B" without --ancestry-path, and limits the latter
 658  * further to the ones that can reach one of the commits in "bottom".
 659  */
 660 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
 661 {
 662         struct commit_list *p;
 663         struct commit_list *rlist = NULL;
 664         int made_progress;
 665
 666         /*
 667          * Reverse the list so that it will be likely that we would
 668          * process parents before children.
 669          */
 670         for (p = list; p; p = p->next)
 671                 commit_list_insert(p->item, &rlist);
 672
 673         for (p = bottom; p; p = p->next)
 674                 p->item->object.flags |= TMP_MARK;
 675
 676         /*
 677          * Mark the ones that can reach bottom commits in "list",
 678          * in a bottom-up fashion.
 679          */
 680         do {
 681                 made_progress = 0;
 682                 for (p = rlist; p; p = p->next) {
 683                         struct commit *c = p->item;
 684                         struct commit_list *parents;
 685                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
 686                                 continue;
 687                         for (parents = c->parents;
 688                              parents;
 689                              parents = parents->next) {
 690                                 if (!(parents->item->object.flags & TMP_MARK))
 691                                         continue;
 692                                 c->object.flags |= TMP_MARK;
 693                                 made_progress = 1;
 694                                 break;
 695                         }
 696                 }
 697         } while (made_progress);
 698
 699         /*
 700          * NEEDSWORK: decide if we want to remove parents that are
 701          * not marked with TMP_MARK from commit->parents for commits
 702          * in the resulting list.  We may not want to do that, though.
 703          */
 704
 705         /*
 706          * The ones that are not marked with TMP_MARK are uninteresting
 707          */
 708         for (p = list; p; p = p->next) {
 709                 struct commit *c = p->item;
 710                 if (c->object.flags & TMP_MARK)
 711                         continue;
 712                 c->object.flags |= UNINTERESTING;
 713         }
 714
 715         /* We are done with the TMP_MARK */
 716         for (p = list; p; p = p->next)
 717                 p->item->object.flags &= ~TMP_MARK;
 718         for (p = bottom; p; p = p->next)
 719                 p->item->object.flags &= ~TMP_MARK;
 720         free_commit_list(rlist);
 721 }
 722
 723 /*
 724  * Before walking the history, keep the set of "negative" refs the
 725  * caller has asked to exclude.
 726  *
 727  * This is used to compute "rev-list --ancestry-path A..B", as we need
 728  * to filter the result of "A..B" further to the ones that can actually
 729  * reach A.
 730  */
 731 static struct commit_list *collect_bottom_commits(struct commit_list *list)
 732 {
 733         struct commit_list *elem, *bottom = NULL;
 734         for (elem = list; elem; elem = elem->next)
 735                 if (elem->item->object.flags & UNINTERESTING)
 736                         commit_list_insert(elem->item, &bottom);
 737         return bottom;
 738 }
 739
 740 /* Assumes either left_only or right_only is set */
 741 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
 742 {
 743         struct commit_list *p;
 744
 745         for (p = list; p; p = p->next) {
 746                 struct commit *commit = p->item;
 747
 748                 if (revs->right_only) {
 749                         if (commit->object.flags & SYMMETRIC_LEFT)
 750                                 commit->object.flags |= SHOWN;
 751                 } else  /* revs->left_only is set */
 752                         if (!(commit->object.flags & SYMMETRIC_LEFT))
 753                                 commit->object.flags |= SHOWN;
 754         }
 755 }
 756
 757 static int limit_list(struct rev_info *revs)
 758 {
 759         int slop = SLOP;
 760         unsigned long date = ~0ul;
 761         struct commit_list *list = revs->commits;
 762         struct commit_list *newlist = NULL;
 763         struct commit_list **p = &newlist;
 764         struct commit_list *bottom = NULL;
 765
 766         if (revs->ancestry_path) {
 767                 bottom = collect_bottom_commits(list);
 768                 if (!bottom)
 769                         die("--ancestry-path given but there are no bottom commits");
 770         }
 771
 772         while (list) {
 773                 struct commit_list *entry = list;
 774                 struct commit *commit = list->item;
 775                 struct object *obj = &commit->object;
 776                 show_early_output_fn_t show;
 777
 778                 list = list->next;
 779                 free(entry);
 780
 781                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 782                         obj->flags |= UNINTERESTING;
 783                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 784                         return -1;
 785                 if (obj->flags & UNINTERESTING) {
 786                         mark_parents_uninteresting(commit);
 787                         if (revs->show_all)
 788                                 p = &commit_list_insert(commit, p)->next;
 789                         slop = still_interesting(list, date, slop);
 790                         if (slop)
 791                                 continue;
 792                         /* If showing all, add the whole pending list to the end */
 793                         if (revs->show_all)
 794                                 *p = list;
 795                         break;
 796                 }
 797                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 798                         continue;
 799                 date = commit->date;
 800                 p = &commit_list_insert(commit, p)->next;
 801
 802                 show = show_early_output;
 803                 if (!show)
 804                         continue;
 805
 806                 show(revs, newlist);
 807                 show_early_output = NULL;
 808         }
 809         if (revs->cherry_pick || revs->cherry_mark)
 810                 cherry_pick_list(newlist, revs);
 811
 812         if (revs->left_only || revs->right_only)
 813                 limit_left_right(newlist, revs);
 814
 815         if (bottom) {
 816                 limit_to_ancestry(bottom, newlist);
 817                 free_commit_list(bottom);
 818         }
 819
 820         revs->commits = newlist;
 821         return 0;
 822 }
 823
 824 struct all_refs_cb {
 825         int all_flags;
 826         int warned_bad_reflog;
 827         struct rev_info *all_revs;
 828         const char *name_for_errormsg;
 829 };
 830
 831 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 832 {
 833         struct all_refs_cb *cb = cb_data;
 834         struct object *object = get_reference(cb->all_revs, path, sha1,
 835                                               cb->all_flags);
 836         add_pending_object(cb->all_revs, object, path);
 837         return 0;
 838 }
 839
 840 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
 841         unsigned flags)
 842 {
 843         cb->all_revs = revs;
 844         cb->all_flags = flags;
 845 }
 846
 847 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
 848                 int (*for_each)(const char *, each_ref_fn, void *))
 849 {
 850         struct all_refs_cb cb;
 851         init_all_refs_cb(&cb, revs, flags);
 852         for_each(submodule, handle_one_ref, &cb);
 853 }
 854
 855 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 856 {
 857         struct all_refs_cb *cb = cb_data;
 858         if (!is_null_sha1(sha1)) {
 859                 struct object *o = parse_object(sha1);
 860                 if (o) {
 861                         o->flags |= cb->all_flags;
 862                         add_pending_object(cb->all_revs, o, "");
 863                 }
 864                 else if (!cb->warned_bad_reflog) {
 865                         warning("reflog of '%s' references pruned commits",
 866                                 cb->name_for_errormsg);
 867                         cb->warned_bad_reflog = 1;
 868                 }
 869         }
 870 }
 871
 872 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 873                 const char *email, unsigned long timestamp, int tz,
 874                 const char *message, void *cb_data)
 875 {
 876         handle_one_reflog_commit(osha1, cb_data);
 877         handle_one_reflog_commit(nsha1, cb_data);
 878         return 0;
 879 }
 880
 881 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 882 {
 883         struct all_refs_cb *cb = cb_data;
 884         cb->warned_bad_reflog = 0;
 885         cb->name_for_errormsg = path;
 886         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 887         return 0;
 888 }
 889
 890 static void handle_reflog(struct rev_info *revs, unsigned flags)
 891 {
 892         struct all_refs_cb cb;
 893         cb.all_revs = revs;
 894         cb.all_flags = flags;
 895         for_each_reflog(handle_one_reflog, &cb);
 896 }
 897
 898 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 899 {
 900         unsigned char sha1[20];
 901         struct object *it;
 902         struct commit *commit;
 903         struct commit_list *parents;
 904
 905         if (*arg == '^') {
 906                 flags ^= UNINTERESTING;
 907                 arg++;
 908         }
 909         if (get_sha1(arg, sha1))
 910                 return 0;
 911         while (1) {
 912                 it = get_reference(revs, arg, sha1, 0);
 913                 if (it->type != OBJ_TAG)
 914                         break;
 915                 if (!((struct tag*)it)->tagged)
 916                         return 0;
 917                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 918         }
 919         if (it->type != OBJ_COMMIT)
 920                 return 0;
 921         commit = (struct commit *)it;
 922         for (parents = commit->parents; parents; parents = parents->next) {
 923                 it = &parents->item->object;
 924                 it->flags |= flags;
 925                 add_pending_object(revs, it, arg);
 926         }
 927         return 1;
 928 }
 929
 930 void init_revisions(struct rev_info *revs, const char *prefix)
 931 {
 932         memset(revs, 0, sizeof(*revs));
 933
 934         revs->abbrev = DEFAULT_ABBREV;
 935         revs->ignore_merges = 1;
 936         revs->simplify_history = 1;
 937         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 938         DIFF_OPT_SET(&revs->pruning, QUICK);
 939         revs->pruning.add_remove = file_add_remove;
 940         revs->pruning.change = file_change;
 941         revs->lifo = 1;
 942         revs->dense = 1;
 943         revs->prefix = prefix;
 944         revs->max_age = -1;
 945         revs->min_age = -1;
 946         revs->skip_count = -1;
 947         revs->max_count = -1;
 948
 949         revs->commit_format = CMIT_FMT_DEFAULT;
 950
 951         revs->grep_filter.status_only = 1;
 952         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 953         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
 954         revs->grep_filter.regflags = REG_NEWLINE;
 955
 956         diff_setup(&revs->diffopt);
 957         if (prefix && !revs->diffopt.prefix) {
 958                 revs->diffopt.prefix = prefix;
 959                 revs->diffopt.prefix_length = strlen(prefix);
 960         }
 961 }
 962
 963 static void add_pending_commit_list(struct rev_info *revs,
 964                                     struct commit_list *commit_list,
 965                                     unsigned int flags)
 966 {
 967         while (commit_list) {
 968                 struct object *object = &commit_list->item->object;
 969                 object->flags |= flags;
 970                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 971                 commit_list = commit_list->next;
 972         }
 973 }
 974
 975 static void prepare_show_merge(struct rev_info *revs)
 976 {
 977         struct commit_list *bases;
 978         struct commit *head, *other;
 979         unsigned char sha1[20];
 980         const char **prune = NULL;
 981         int i, prune_num = 1; /* counting terminating NULL */
 982
 983         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 984                 die("--merge without HEAD?");
 985         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 986                 die("--merge without MERGE_HEAD?");
 987         add_pending_object(revs, &head->object, "HEAD");
 988         add_pending_object(revs, &other->object, "MERGE_HEAD");
 989         bases = get_merge_bases(head, other, 1);
 990         add_pending_commit_list(revs, bases, UNINTERESTING);
 991         free_commit_list(bases);
 992         head->object.flags |= SYMMETRIC_LEFT;
 993
 994         if (!active_nr)
 995                 read_cache();
 996         for (i = 0; i < active_nr; i++) {
 997                 struct cache_entry *ce = active_cache[i];
 998                 if (!ce_stage(ce))
 999                         continue;
1000                 if (ce_path_match(ce, revs->prune_data)) {
1001                         prune_num++;
1002                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
1003                         prune[prune_num-2] = ce->name;
1004                         prune[prune_num-1] = NULL;
1005                 }
1006                 while ((i+1 < active_nr) &&
1007                        ce_same_name(ce, active_cache[i+1]))
1008                         i++;
1009         }
1010         revs->prune_data = prune;
1011         revs->limited = 1;
1012 }
1013
1014 int handle_revision_arg(const char *arg, struct rev_info *revs,
1015                         int flags,
1016                         int cant_be_filename)
1017 {
1018         unsigned mode;
1019         char *dotdot;
1020         struct object *object;
1021         unsigned char sha1[20];
1022         int local_flags;
1023
1024         dotdot = strstr(arg, "..");
1025         if (dotdot) {
1026                 unsigned char from_sha1[20];
1027                 const char *next = dotdot + 2;
1028                 const char *this = arg;
1029                 int symmetric = *next == '.';
1030                 unsigned int flags_exclude = flags ^ UNINTERESTING;
1031
1032                 *dotdot = 0;
1033                 next += symmetric;
1034
1035                 if (!*next)
1036                         next = "HEAD";
1037                 if (dotdot == arg)
1038                         this = "HEAD";
1039                 if (!get_sha1(this, from_sha1) &&
1040                     !get_sha1(next, sha1)) {
1041                         struct commit *a, *b;
1042                         struct commit_list *exclude;
1043
1044                         a = lookup_commit_reference(from_sha1);
1045                         b = lookup_commit_reference(sha1);
1046                         if (!a || !b) {
1047                                 die(symmetric ?
1048                                     "Invalid symmetric difference expression %s...%s" :
1049                                     "Invalid revision range %s..%s",
1050                                     arg, next);
1051                         }
1052
1053                         if (!cant_be_filename) {
1054                                 *dotdot = '.';
1055                                 verify_non_filename(revs->prefix, arg);
1056                         }
1057
1058                         if (symmetric) {
1059                                 exclude = get_merge_bases(a, b, 1);
1060                                 add_pending_commit_list(revs, exclude,
1061                                                         flags_exclude);
1062                                 free_commit_list(exclude);
1063                                 a->object.flags |= flags | SYMMETRIC_LEFT;
1064                         } else
1065                                 a->object.flags |= flags_exclude;
1066                         b->object.flags |= flags;
1067                         add_pending_object(revs, &a->object, this);
1068                         add_pending_object(revs, &b->object, next);
1069                         return 0;
1070                 }
1071                 *dotdot = '.';
1072         }
1073         dotdot = strstr(arg, "^@");
1074         if (dotdot && !dotdot[2]) {
1075                 *dotdot = 0;
1076                 if (add_parents_only(revs, arg, flags))
1077                         return 0;
1078                 *dotdot = '^';
1079         }
1080         dotdot = strstr(arg, "^!");
1081         if (dotdot && !dotdot[2]) {
1082                 *dotdot = 0;
1083                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
1084                         *dotdot = '^';
1085         }
1086
1087         local_flags = 0;
1088         if (*arg == '^') {
1089                 local_flags = UNINTERESTING;
1090                 arg++;
1091         }
1092         if (get_sha1_with_mode(arg, sha1, &mode))
1093                 return -1;
1094         if (!cant_be_filename)
1095                 verify_non_filename(revs->prefix, arg);
1096         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1097         add_pending_object_with_mode(revs, object, arg, mode);
1098         return 0;
1099 }
1100
1101 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
1102 {
1103         const char **prune = *prune_data;
1104         int prune_nr;
1105         int prune_alloc;
1106
1107         /* count existing ones */
1108         if (!prune)
1109                 prune_nr = 0;
1110         else
1111                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1112                         ;
1113         prune_alloc = prune_nr; /* not really, but we do not know */
1114
1115         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1116                 int len = sb->len;
1117                 if (len && sb->buf[len - 1] == '\n')
1118                         sb->buf[--len] = '\0';
1119                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1120                 prune[prune_nr++] = xstrdup(sb->buf);
1121         }
1122         if (prune) {
1123                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1124                 prune[prune_nr] = NULL;
1125         }
1126         *prune_data = prune;
1127 }
1128
1129 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1130 {
1131         struct strbuf sb;
1132         int seen_dashdash = 0;
1133
1134         strbuf_init(&sb, 1000);
1135         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1136                 int len = sb.len;
1137                 if (len && sb.buf[len - 1] == '\n')
1138                         sb.buf[--len] = '\0';
1139                 if (!len)
1140                         break;
1141                 if (sb.buf[0] == '-') {
1142                         if (len == 2 && sb.buf[1] == '-') {
1143                                 seen_dashdash = 1;
1144                                 break;
1145                         }
1146                         die("options not supported in --stdin mode");
1147                 }
1148                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1149                         die("bad revision '%s'", sb.buf);
1150         }
1151         if (seen_dashdash)
1152                 read_pathspec_from_stdin(revs, &sb, prune);
1153         strbuf_release(&sb);
1154 }
1155
1156 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1157 {
1158         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1159 }
1160
1161 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1162 {
1163         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1164 }
1165
1166 static void add_message_grep(struct rev_info *revs, const char *pattern)
1167 {
1168         add_grep(revs, pattern, GREP_PATTERN_BODY);
1169 }
1170
1171 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1172                                int *unkc, const char **unkv)
1173 {
1174         const char *arg = argv[0];
1175         const char *optarg;
1176         int argcount;
1177
1178         /* pseudo revision arguments */
1179         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1180             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1181             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1182             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1183             !strcmp(arg, "--bisect"))
1184         {
1185                 unkv[(*unkc)++] = arg;
1186                 return 1;
1187         }
1188
1189         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1190                 revs->max_count = atoi(optarg);
1191                 revs->no_walk = 0;
1192                 return argcount;
1193         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1194                 revs->skip_count = atoi(optarg);
1195                 return argcount;
1196         } else if ((*arg == '-') && isdigit(arg[1])) {
1197         /* accept -<digit>, like traditional "head" */
1198                 revs->max_count = atoi(arg + 1);
1199                 revs->no_walk = 0;
1200         } else if (!strcmp(arg, "-n")) {
1201                 if (argc <= 1)
1202                         return error("-n requires an argument");
1203                 revs->max_count = atoi(argv[1]);
1204                 revs->no_walk = 0;
1205                 return 2;
1206         } else if (!prefixcmp(arg, "-n")) {
1207                 revs->max_count = atoi(arg + 2);
1208                 revs->no_walk = 0;
1209         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1210                 revs->max_age = atoi(optarg);
1211                 return argcount;
1212         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1213                 revs->max_age = approxidate(optarg);
1214                 return argcount;
1215         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1216                 revs->max_age = approxidate(optarg);
1217                 return argcount;
1218         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1219                 revs->min_age = atoi(optarg);
1220                 return argcount;
1221         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1222                 revs->min_age = approxidate(optarg);
1223                 return argcount;
1224         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1225                 revs->min_age = approxidate(optarg);
1226                 return argcount;
1227         } else if (!strcmp(arg, "--first-parent")) {
1228                 revs->first_parent_only = 1;
1229         } else if (!strcmp(arg, "--ancestry-path")) {
1230                 revs->ancestry_path = 1;
1231                 revs->simplify_history = 0;
1232                 revs->limited = 1;
1233         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1234                 init_reflog_walk(&revs->reflog_info);
1235         } else if (!strcmp(arg, "--default")) {
1236                 if (argc <= 1)
1237                         return error("bad --default argument");
1238                 revs->def = argv[1];
1239                 return 2;
1240         } else if (!strcmp(arg, "--merge")) {
1241                 revs->show_merge = 1;
1242         } else if (!strcmp(arg, "--topo-order")) {
1243                 revs->lifo = 1;
1244                 revs->topo_order = 1;
1245         } else if (!strcmp(arg, "--simplify-merges")) {
1246                 revs->simplify_merges = 1;
1247                 revs->rewrite_parents = 1;
1248                 revs->simplify_history = 0;
1249                 revs->limited = 1;
1250         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1251                 revs->simplify_merges = 1;
1252                 revs->rewrite_parents = 1;
1253                 revs->simplify_history = 0;
1254                 revs->simplify_by_decoration = 1;
1255                 revs->limited = 1;
1256                 revs->prune = 1;
1257                 load_ref_decorations(DECORATE_SHORT_REFS);
1258         } else if (!strcmp(arg, "--date-order")) {
1259                 revs->lifo = 0;
1260                 revs->topo_order = 1;
1261         } else if (!prefixcmp(arg, "--early-output")) {
1262                 int count = 100;
1263                 switch (arg[14]) {
1264                 case '=':
1265                         count = atoi(arg+15);
1266                         /* Fallthrough */
1267                 case 0:
1268                         revs->topo_order = 1;
1269                        revs->early_output = count;
1270                 }
1271         } else if (!strcmp(arg, "--parents")) {
1272                 revs->rewrite_parents = 1;
1273                 revs->print_parents = 1;
1274         } else if (!strcmp(arg, "--dense")) {
1275                 revs->dense = 1;
1276         } else if (!strcmp(arg, "--sparse")) {
1277                 revs->dense = 0;
1278         } else if (!strcmp(arg, "--show-all")) {
1279                 revs->show_all = 1;
1280         } else if (!strcmp(arg, "--remove-empty")) {
1281                 revs->remove_empty_trees = 1;
1282         } else if (!strcmp(arg, "--merges")) {
1283                 revs->merges_only = 1;
1284         } else if (!strcmp(arg, "--no-merges")) {
1285                 revs->no_merges = 1;
1286         } else if (!strcmp(arg, "--boundary")) {
1287                 revs->boundary = 1;
1288         } else if (!strcmp(arg, "--left-right")) {
1289                 revs->left_right = 1;
1290         } else if (!strcmp(arg, "--left-only")) {
1291                 if (revs->right_only)
1292                         die("--left-only is incompatible with --right-only");
1293                 revs->left_only = 1;
1294         } else if (!strcmp(arg, "--right-only")) {
1295                 if (revs->left_only)
1296                         die("--right-only is incompatible with --left-only");
1297                 revs->right_only = 1;
1298         } else if (!strcmp(arg, "--count")) {
1299                 revs->count = 1;
1300         } else if (!strcmp(arg, "--cherry-mark")) {
1301                 if (revs->cherry_pick)
1302                         die("--cherry-mark is incompatible with --cherry-pick");
1303                 revs->cherry_mark = 1;
1304                 revs->limited = 1; /* needs limit_list() */
1305         } else if (!strcmp(arg, "--cherry-pick")) {
1306                 if (revs->cherry_mark)
1307                         die("--cherry-pick is incompatible with --cherry-mark");
1308                 revs->cherry_pick = 1;
1309                 revs->limited = 1;
1310         } else if (!strcmp(arg, "--objects")) {
1311                 revs->tag_objects = 1;
1312                 revs->tree_objects = 1;
1313                 revs->blob_objects = 1;
1314         } else if (!strcmp(arg, "--objects-edge")) {
1315                 revs->tag_objects = 1;
1316                 revs->tree_objects = 1;
1317                 revs->blob_objects = 1;
1318                 revs->edge_hint = 1;
1319         } else if (!strcmp(arg, "--unpacked")) {
1320                 revs->unpacked = 1;
1321         } else if (!prefixcmp(arg, "--unpacked=")) {
1322                 die("--unpacked=<packfile> no longer supported.");
1323         } else if (!strcmp(arg, "-r")) {
1324                 revs->diff = 1;
1325                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1326         } else if (!strcmp(arg, "-t")) {
1327                 revs->diff = 1;
1328                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1329                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1330         } else if (!strcmp(arg, "-m")) {
1331                 revs->ignore_merges = 0;
1332         } else if (!strcmp(arg, "-c")) {
1333                 revs->diff = 1;
1334                 revs->dense_combined_merges = 0;
1335                 revs->combine_merges = 1;
1336         } else if (!strcmp(arg, "--cc")) {
1337                 revs->diff = 1;
1338                 revs->dense_combined_merges = 1;
1339                 revs->combine_merges = 1;
1340         } else if (!strcmp(arg, "-v")) {
1341                 revs->verbose_header = 1;
1342         } else if (!strcmp(arg, "--pretty")) {
1343                 revs->verbose_header = 1;
1344                 revs->pretty_given = 1;
1345                 get_commit_format(arg+8, revs);
1346         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1347                 /*
1348                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1349                  * not allowed, since the argument is optional.
1350                  */
1351                 revs->verbose_header = 1;
1352                 revs->pretty_given = 1;
1353                 get_commit_format(arg+9, revs);
1354         } else if (!strcmp(arg, "--show-notes")) {
1355                 revs->show_notes = 1;
1356                 revs->show_notes_given = 1;
1357         } else if (!prefixcmp(arg, "--show-notes=")) {
1358                 struct strbuf buf = STRBUF_INIT;
1359                 revs->show_notes = 1;
1360                 revs->show_notes_given = 1;
1361                 if (!revs->notes_opt.extra_notes_refs)
1362                         revs->notes_opt.extra_notes_refs = xcalloc(1, sizeof(struct string_list));
1363                 if (!prefixcmp(arg+13, "refs/"))
1364                         /* happy */;
1365                 else if (!prefixcmp(arg+13, "notes/"))
1366                         strbuf_addstr(&buf, "refs/");
1367                 else
1368                         strbuf_addstr(&buf, "refs/notes/");
1369                 strbuf_addstr(&buf, arg+13);
1370                 string_list_append(revs->notes_opt.extra_notes_refs,
1371                                    strbuf_detach(&buf, NULL));
1372         } else if (!strcmp(arg, "--no-notes")) {
1373                 revs->show_notes = 0;
1374                 revs->show_notes_given = 1;
1375         } else if (!strcmp(arg, "--standard-notes")) {
1376                 revs->show_notes_given = 1;
1377                 revs->notes_opt.suppress_default_notes = 0;
1378         } else if (!strcmp(arg, "--no-standard-notes")) {
1379                 revs->notes_opt.suppress_default_notes = 1;
1380         } else if (!strcmp(arg, "--oneline")) {
1381                 revs->verbose_header = 1;
1382                 get_commit_format("oneline", revs);
1383                 revs->pretty_given = 1;
1384                 revs->abbrev_commit = 1;
1385         } else if (!strcmp(arg, "--graph")) {
1386                 revs->topo_order = 1;
1387                 revs->rewrite_parents = 1;
1388                 revs->graph = graph_init(revs);
1389         } else if (!strcmp(arg, "--root")) {
1390                 revs->show_root_diff = 1;
1391         } else if (!strcmp(arg, "--no-commit-id")) {
1392                 revs->no_commit_id = 1;
1393         } else if (!strcmp(arg, "--always")) {
1394                 revs->always_show_header = 1;
1395         } else if (!strcmp(arg, "--no-abbrev")) {
1396                 revs->abbrev = 0;
1397         } else if (!strcmp(arg, "--abbrev")) {
1398                 revs->abbrev = DEFAULT_ABBREV;
1399         } else if (!prefixcmp(arg, "--abbrev=")) {
1400                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1401                 if (revs->abbrev < MINIMUM_ABBREV)
1402                         revs->abbrev = MINIMUM_ABBREV;
1403                 else if (revs->abbrev > 40)
1404                         revs->abbrev = 40;
1405         } else if (!strcmp(arg, "--abbrev-commit")) {
1406                 revs->abbrev_commit = 1;
1407         } else if (!strcmp(arg, "--full-diff")) {
1408                 revs->diff = 1;
1409                 revs->full_diff = 1;
1410         } else if (!strcmp(arg, "--full-history")) {
1411                 revs->simplify_history = 0;
1412         } else if (!strcmp(arg, "--relative-date")) {
1413                 revs->date_mode = DATE_RELATIVE;
1414                 revs->date_mode_explicit = 1;
1415         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1416                 revs->date_mode = parse_date_format(optarg);
1417                 revs->date_mode_explicit = 1;
1418                 return argcount;
1419         } else if (!strcmp(arg, "--log-size")) {
1420                 revs->show_log_size = 1;
1421         }
1422         /*
1423          * Grepping the commit log
1424          */
1425         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1426                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1427                 return argcount;
1428         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1429                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1430                 return argcount;
1431         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1432                 add_message_grep(revs, optarg);
1433                 return argcount;
1434         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1435                 revs->grep_filter.regflags |= REG_EXTENDED;
1436         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1437                 revs->grep_filter.regflags |= REG_ICASE;
1438         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1439                 revs->grep_filter.fixed = 1;
1440         } else if (!strcmp(arg, "--all-match")) {
1441                 revs->grep_filter.all_match = 1;
1442         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1443                 if (strcmp(optarg, "none"))
1444                         git_log_output_encoding = xstrdup(optarg);
1445                 else
1446                         git_log_output_encoding = "";
1447                 return argcount;
1448         } else if (!strcmp(arg, "--reverse")) {
1449                 revs->reverse ^= 1;
1450         } else if (!strcmp(arg, "--children")) {
1451                 revs->children.name = "children";
1452                 revs->limited = 1;
1453         } else {
1454                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1455                 if (!opts)
1456                         unkv[(*unkc)++] = arg;
1457                 return opts;
1458         }
1459
1460         return 1;
1461 }
1462
1463 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1464                         const struct option *options,
1465                         const char * const usagestr[])
1466 {
1467         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1468                                     &ctx->cpidx, ctx->out);
1469         if (n <= 0) {
1470                 error("unknown option `%s'", ctx->argv[0]);
1471                 usage_with_options(usagestr, options);
1472         }
1473         ctx->argv += n;
1474         ctx->argc -= n;
1475 }
1476
1477 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1478 {
1479         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1480 }
1481
1482 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1483 {
1484         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1485 }
1486
1487 static void append_prune_data(const char ***prune_data, const char **av)
1488 {
1489         const char **prune = *prune_data;
1490         int prune_nr;
1491         int prune_alloc;
1492
1493         if (!prune) {
1494                 *prune_data = av;
1495                 return;
1496         }
1497
1498         /* count existing ones */
1499         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1500                 ;
1501         prune_alloc = prune_nr; /* not really, but we do not know */
1502
1503         while (*av) {
1504                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1505                 prune[prune_nr++] = *av;
1506                 av++;
1507         }
1508         if (prune) {
1509                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1510                 prune[prune_nr] = NULL;
1511         }
1512         *prune_data = prune;
1513 }
1514
1515 /*
1516  * Parse revision information, filling in the "rev_info" structure,
1517  * and removing the used arguments from the argument list.
1518  *
1519  * Returns the number of arguments left that weren't recognized
1520  * (which are also moved to the head of the argument list)
1521  */
1522 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1523 {
1524         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1525         const char **prune_data = NULL;
1526         const char *submodule = NULL;
1527         const char *optarg;
1528         int argcount;
1529
1530         if (opt)
1531                 submodule = opt->submodule;
1532
1533         /* First, search for "--" */
1534         seen_dashdash = 0;
1535         for (i = 1; i < argc; i++) {
1536                 const char *arg = argv[i];
1537                 if (strcmp(arg, "--"))
1538                         continue;
1539                 argv[i] = NULL;
1540                 argc = i;
1541                 if (argv[i + 1])
1542                         prune_data = argv + i + 1;
1543                 seen_dashdash = 1;
1544                 break;
1545         }
1546
1547         /* Second, deal with arguments and options */
1548         flags = 0;
1549         read_from_stdin = 0;
1550         for (left = i = 1; i < argc; i++) {
1551                 const char *arg = argv[i];
1552                 if (*arg == '-') {
1553                         int opts;
1554
1555                         if (!strcmp(arg, "--all")) {
1556                                 handle_refs(submodule, revs, flags, for_each_ref_submodule);
1557                                 handle_refs(submodule, revs, flags, head_ref_submodule);
1558                                 continue;
1559                         }
1560                         if (!strcmp(arg, "--branches")) {
1561                                 handle_refs(submodule, revs, flags, for_each_branch_ref_submodule);
1562                                 continue;
1563                         }
1564                         if (!strcmp(arg, "--bisect")) {
1565                                 handle_refs(submodule, revs, flags, for_each_bad_bisect_ref);
1566                                 handle_refs(submodule, revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1567                                 revs->bisect = 1;
1568                                 continue;
1569                         }
1570                         if (!strcmp(arg, "--tags")) {
1571                                 handle_refs(submodule, revs, flags, for_each_tag_ref_submodule);
1572                                 continue;
1573                         }
1574                         if (!strcmp(arg, "--remotes")) {
1575                                 handle_refs(submodule, revs, flags, for_each_remote_ref_submodule);
1576                                 continue;
1577                         }
1578                         if ((argcount = parse_long_opt("glob", argv + i, &optarg))) {
1579                                 struct all_refs_cb cb;
1580                                 i += argcount - 1;
1581                                 init_all_refs_cb(&cb, revs, flags);
1582                                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1583                                 continue;
1584                         }
1585                         if (!prefixcmp(arg, "--branches=")) {
1586                                 struct all_refs_cb cb;
1587                                 init_all_refs_cb(&cb, revs, flags);
1588                                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1589                                 continue;
1590                         }
1591                         if (!prefixcmp(arg, "--tags=")) {
1592                                 struct all_refs_cb cb;
1593                                 init_all_refs_cb(&cb, revs, flags);
1594                                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1595                                 continue;
1596                         }
1597                         if (!prefixcmp(arg, "--remotes=")) {
1598                                 struct all_refs_cb cb;
1599                                 init_all_refs_cb(&cb, revs, flags);
1600                                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1601                                 continue;
1602                         }
1603                         if (!strcmp(arg, "--reflog")) {
1604                                 handle_reflog(revs, flags);
1605                                 continue;
1606                         }
1607                         if (!strcmp(arg, "--not")) {
1608                                 flags ^= UNINTERESTING;
1609                                 continue;
1610                         }
1611                         if (!strcmp(arg, "--no-walk")) {
1612                                 revs->no_walk = 1;
1613                                 continue;
1614                         }
1615                         if (!strcmp(arg, "--do-walk")) {
1616                                 revs->no_walk = 0;
1617                                 continue;
1618                         }
1619                         if (!strcmp(arg, "--stdin")) {
1620                                 if (revs->disable_stdin) {
1621                                         argv[left++] = arg;
1622                                         continue;
1623                                 }
1624                                 if (read_from_stdin++)
1625                                         die("--stdin given twice?");
1626                                 read_revisions_from_stdin(revs, &prune_data);
1627                                 continue;
1628                         }
1629
1630                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1631                         if (opts > 0) {
1632                                 i += opts - 1;
1633                                 continue;
1634                         }
1635                         if (opts < 0)
1636                                 exit(128);
1637                         continue;
1638                 }
1639
1640                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1641                         int j;
1642                         if (seen_dashdash || *arg == '^')
1643                                 die("bad revision '%s'", arg);
1644
1645                         /* If we didn't have a "--":
1646                          * (1) all filenames must exist;
1647                          * (2) all rev-args must not be interpretable
1648                          *     as a valid filename.
1649                          * but the latter we have checked in the main loop.
1650                          */
1651                         for (j = i; j < argc; j++)
1652                                 verify_filename(revs->prefix, argv[j]);
1653
1654                         append_prune_data(&prune_data, argv + i);
1655                         break;
1656                 }
1657                 else
1658                         got_rev_arg = 1;
1659         }
1660
1661         if (prune_data)
1662                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1663
1664         if (revs->def == NULL)
1665                 revs->def = opt ? opt->def : NULL;
1666         if (opt && opt->tweak)
1667                 opt->tweak(revs, opt);
1668         if (revs->show_merge)
1669                 prepare_show_merge(revs);
1670         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1671                 unsigned char sha1[20];
1672                 struct object *object;
1673                 unsigned mode;
1674                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1675                         die("bad default revision '%s'", revs->def);
1676                 object = get_reference(revs, revs->def, sha1, 0);
1677                 add_pending_object_with_mode(revs, object, revs->def, mode);
1678         }
1679
1680         /* Did the user ask for any diff output? Run the diff! */
1681         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1682                 revs->diff = 1;
1683
1684         /* Pickaxe, diff-filter and rename following need diffs */
1685         if (revs->diffopt.pickaxe ||
1686             revs->diffopt.filter ||
1687             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1688                 revs->diff = 1;
1689
1690         if (revs->topo_order)
1691                 revs->limited = 1;
1692
1693         if (revs->prune_data) {
1694                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1695                 /* Can't prune commits with rename following: the paths change.. */
1696                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1697                         revs->prune = 1;
1698                 if (!revs->full_diff)
1699                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1700         }
1701         if (revs->combine_merges)
1702                 revs->ignore_merges = 0;
1703         revs->diffopt.abbrev = revs->abbrev;
1704         if (diff_setup_done(&revs->diffopt) < 0)
1705                 die("diff_setup_done failed");
1706
1707         compile_grep_patterns(&revs->grep_filter);
1708
1709         if (revs->reverse && revs->reflog_info)
1710                 die("cannot combine --reverse with --walk-reflogs");
1711         if (revs->rewrite_parents && revs->children.name)
1712                 die("cannot combine --parents and --children");
1713
1714         /*
1715          * Limitations on the graph functionality
1716          */
1717         if (revs->reverse && revs->graph)
1718                 die("cannot combine --reverse with --graph");
1719
1720         if (revs->reflog_info && revs->graph)
1721                 die("cannot combine --walk-reflogs with --graph");
1722
1723         return left;
1724 }
1725
1726 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1727 {
1728         struct commit_list *l = xcalloc(1, sizeof(*l));
1729
1730         l->item = child;
1731         l->next = add_decoration(&revs->children, &parent->object, l);
1732 }
1733
1734 static int remove_duplicate_parents(struct commit *commit)
1735 {
1736         struct commit_list **pp, *p;
1737         int surviving_parents;
1738
1739         /* Examine existing parents while marking ones we have seen... */
1740         pp = &commit->parents;
1741         while ((p = *pp) != NULL) {
1742                 struct commit *parent = p->item;
1743                 if (parent->object.flags & TMP_MARK) {
1744                         *pp = p->next;
1745                         continue;
1746                 }
1747                 parent->object.flags |= TMP_MARK;
1748                 pp = &p->next;
1749         }
1750         /* count them while clearing the temporary mark */
1751         surviving_parents = 0;
1752         for (p = commit->parents; p; p = p->next) {
1753                 p->item->object.flags &= ~TMP_MARK;
1754                 surviving_parents++;
1755         }
1756         return surviving_parents;
1757 }
1758
1759 struct merge_simplify_state {
1760         struct commit *simplified;
1761 };
1762
1763 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1764 {
1765         struct merge_simplify_state *st;
1766
1767         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1768         if (!st) {
1769                 st = xcalloc(1, sizeof(*st));
1770                 add_decoration(&revs->merge_simplification, &commit->object, st);
1771         }
1772         return st;
1773 }
1774
1775 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1776 {
1777         struct commit_list *p;
1778         struct merge_simplify_state *st, *pst;
1779         int cnt;
1780
1781         st = locate_simplify_state(revs, commit);
1782
1783         /*
1784          * Have we handled this one?
1785          */
1786         if (st->simplified)
1787                 return tail;
1788
1789         /*
1790          * An UNINTERESTING commit simplifies to itself, so does a
1791          * root commit.  We do not rewrite parents of such commit
1792          * anyway.
1793          */
1794         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1795                 st->simplified = commit;
1796                 return tail;
1797         }
1798
1799         /*
1800          * Do we know what commit all of our parents should be rewritten to?
1801          * Otherwise we are not ready to rewrite this one yet.
1802          */
1803         for (cnt = 0, p = commit->parents; p; p = p->next) {
1804                 pst = locate_simplify_state(revs, p->item);
1805                 if (!pst->simplified) {
1806                         tail = &commit_list_insert(p->item, tail)->next;
1807                         cnt++;
1808                 }
1809         }
1810         if (cnt) {
1811                 tail = &commit_list_insert(commit, tail)->next;
1812                 return tail;
1813         }
1814
1815         /*
1816          * Rewrite our list of parents.
1817          */
1818         for (p = commit->parents; p; p = p->next) {
1819                 pst = locate_simplify_state(revs, p->item);
1820                 p->item = pst->simplified;
1821         }
1822         cnt = remove_duplicate_parents(commit);
1823
1824         /*
1825          * It is possible that we are a merge and one side branch
1826          * does not have any commit that touches the given paths;
1827          * in such a case, the immediate parents will be rewritten
1828          * to different commits.
1829          *
1830          *      o----X          X: the commit we are looking at;
1831          *     /    /           o: a commit that touches the paths;
1832          * ---o----'
1833          *
1834          * Further reduce the parents by removing redundant parents.
1835          */
1836         if (1 < cnt) {
1837                 struct commit_list *h = reduce_heads(commit->parents);
1838                 cnt = commit_list_count(h);
1839                 free_commit_list(commit->parents);
1840                 commit->parents = h;
1841         }
1842
1843         /*
1844          * A commit simplifies to itself if it is a root, if it is
1845          * UNINTERESTING, if it touches the given paths, or if it is a
1846          * merge and its parents simplifies to more than one commits
1847          * (the first two cases are already handled at the beginning of
1848          * this function).
1849          *
1850          * Otherwise, it simplifies to what its sole parent simplifies to.
1851          */
1852         if (!cnt ||
1853             (commit->object.flags & UNINTERESTING) ||
1854             !(commit->object.flags & TREESAME) ||
1855             (1 < cnt))
1856                 st->simplified = commit;
1857         else {
1858                 pst = locate_simplify_state(revs, commit->parents->item);
1859                 st->simplified = pst->simplified;
1860         }
1861         return tail;
1862 }
1863
1864 static void simplify_merges(struct rev_info *revs)
1865 {
1866         struct commit_list *list;
1867         struct commit_list *yet_to_do, **tail;
1868
1869         if (!revs->topo_order)
1870                 sort_in_topological_order(&revs->commits, revs->lifo);
1871         if (!revs->prune)
1872                 return;
1873
1874         /* feed the list reversed */
1875         yet_to_do = NULL;
1876         for (list = revs->commits; list; list = list->next)
1877                 commit_list_insert(list->item, &yet_to_do);
1878         while (yet_to_do) {
1879                 list = yet_to_do;
1880                 yet_to_do = NULL;
1881                 tail = &yet_to_do;
1882                 while (list) {
1883                         struct commit *commit = list->item;
1884                         struct commit_list *next = list->next;
1885                         free(list);
1886                         list = next;
1887                         tail = simplify_one(revs, commit, tail);
1888                 }
1889         }
1890
1891         /* clean up the result, removing the simplified ones */
1892         list = revs->commits;
1893         revs->commits = NULL;
1894         tail = &revs->commits;
1895         while (list) {
1896                 struct commit *commit = list->item;
1897                 struct commit_list *next = list->next;
1898                 struct merge_simplify_state *st;
1899                 free(list);
1900                 list = next;
1901                 st = locate_simplify_state(revs, commit);
1902                 if (st->simplified == commit)
1903                         tail = &commit_list_insert(commit, tail)->next;
1904         }
1905 }
1906
1907 static void set_children(struct rev_info *revs)
1908 {
1909         struct commit_list *l;
1910         for (l = revs->commits; l; l = l->next) {
1911                 struct commit *commit = l->item;
1912                 struct commit_list *p;
1913
1914                 for (p = commit->parents; p; p = p->next)
1915                         add_child(revs, p->item, commit);
1916         }
1917 }
1918
1919 int prepare_revision_walk(struct rev_info *revs)
1920 {
1921         int nr = revs->pending.nr;
1922         struct object_array_entry *e, *list;
1923
1924         e = list = revs->pending.objects;
1925         revs->pending.nr = 0;
1926         revs->pending.alloc = 0;
1927         revs->pending.objects = NULL;
1928         while (--nr >= 0) {
1929                 struct commit *commit = handle_commit(revs, e->item, e->name);
1930                 if (commit) {
1931                         if (!(commit->object.flags & SEEN)) {
1932                                 commit->object.flags |= SEEN;
1933                                 commit_list_insert_by_date(commit, &revs->commits);
1934                         }
1935                 }
1936                 e++;
1937         }
1938         free(list);
1939
1940         if (revs->no_walk)
1941                 return 0;
1942         if (revs->limited)
1943                 if (limit_list(revs) < 0)
1944                         return -1;
1945         if (revs->topo_order)
1946                 sort_in_topological_order(&revs->commits, revs->lifo);
1947         if (revs->simplify_merges)
1948                 simplify_merges(revs);
1949         if (revs->children.name)
1950                 set_children(revs);
1951         return 0;
1952 }
1953
1954 enum rewrite_result {
1955         rewrite_one_ok,
1956         rewrite_one_noparents,
1957         rewrite_one_error
1958 };
1959
1960 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1961 {
1962         struct commit_list *cache = NULL;
1963
1964         for (;;) {
1965                 struct commit *p = *pp;
1966                 if (!revs->limited)
1967                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1968                                 return rewrite_one_error;
1969                 if (p->parents && p->parents->next)
1970                         return rewrite_one_ok;
1971                 if (p->object.flags & UNINTERESTING)
1972                         return rewrite_one_ok;
1973                 if (!(p->object.flags & TREESAME))
1974                         return rewrite_one_ok;
1975                 if (!p->parents)
1976                         return rewrite_one_noparents;
1977                 *pp = p->parents->item;
1978         }
1979 }
1980
1981 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1982 {
1983         struct commit_list **pp = &commit->parents;
1984         while (*pp) {
1985                 struct commit_list *parent = *pp;
1986                 switch (rewrite_one(revs, &parent->item)) {
1987                 case rewrite_one_ok:
1988                         break;
1989                 case rewrite_one_noparents:
1990                         *pp = parent->next;
1991                         continue;
1992                 case rewrite_one_error:
1993                         return -1;
1994                 }
1995                 pp = &parent->next;
1996         }
1997         remove_duplicate_parents(commit);
1998         return 0;
1999 }
2000
2001 static int commit_match(struct commit *commit, struct rev_info *opt)
2002 {
2003         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2004                 return 1;
2005         return grep_buffer(&opt->grep_filter,
2006                            NULL, /* we say nothing, not even filename */
2007                            commit->buffer, strlen(commit->buffer));
2008 }
2009
2010 static inline int want_ancestry(struct rev_info *revs)
2011 {
2012         return (revs->rewrite_parents || revs->children.name);
2013 }
2014
2015 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2016 {
2017         if (commit->object.flags & SHOWN)
2018                 return commit_ignore;
2019         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2020                 return commit_ignore;
2021         if (revs->show_all)
2022                 return commit_show;
2023         if (commit->object.flags & UNINTERESTING)
2024                 return commit_ignore;
2025         if (revs->min_age != -1 && (commit->date > revs->min_age))
2026                 return commit_ignore;
2027         if (revs->no_merges && commit->parents && commit->parents->next)
2028                 return commit_ignore;
2029         if (revs->merges_only && !(commit->parents && commit->parents->next))
2030                 return commit_ignore;
2031         if (!commit_match(commit, revs))
2032                 return commit_ignore;
2033         if (revs->prune && revs->dense) {
2034                 /* Commit without changes? */
2035                 if (commit->object.flags & TREESAME) {
2036                         /* drop merges unless we want parenthood */
2037                         if (!want_ancestry(revs))
2038                                 return commit_ignore;
2039                         /* non-merge - always ignore it */
2040                         if (!commit->parents || !commit->parents->next)
2041                                 return commit_ignore;
2042                 }
2043         }
2044         return commit_show;
2045 }
2046
2047 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2048 {
2049         enum commit_action action = get_commit_action(revs, commit);
2050
2051         if (action == commit_show &&
2052             !revs->show_all &&
2053             revs->prune && revs->dense && want_ancestry(revs)) {
2054                 if (rewrite_parents(revs, commit) < 0)
2055                         return commit_error;
2056         }
2057         return action;
2058 }
2059
2060 static struct commit *get_revision_1(struct rev_info *revs)
2061 {
2062         if (!revs->commits)
2063                 return NULL;
2064
2065         do {
2066                 struct commit_list *entry = revs->commits;
2067                 struct commit *commit = entry->item;
2068
2069                 revs->commits = entry->next;
2070                 free(entry);
2071
2072                 if (revs->reflog_info) {
2073                         fake_reflog_parent(revs->reflog_info, commit);
2074                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2075                 }
2076
2077                 /*
2078                  * If we haven't done the list limiting, we need to look at
2079                  * the parents here. We also need to do the date-based limiting
2080                  * that we'd otherwise have done in limit_list().
2081                  */
2082                 if (!revs->limited) {
2083                         if (revs->max_age != -1 &&
2084                             (commit->date < revs->max_age))
2085                                 continue;
2086                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2087                                 die("Failed to traverse parents of commit %s",
2088                                     sha1_to_hex(commit->object.sha1));
2089                 }
2090
2091                 switch (simplify_commit(revs, commit)) {
2092                 case commit_ignore:
2093                         continue;
2094                 case commit_error:
2095                         die("Failed to simplify parents of commit %s",
2096                             sha1_to_hex(commit->object.sha1));
2097                 default:
2098                         return commit;
2099                 }
2100         } while (revs->commits);
2101         return NULL;
2102 }
2103
2104 static void gc_boundary(struct object_array *array)
2105 {
2106         unsigned nr = array->nr;
2107         unsigned alloc = array->alloc;
2108         struct object_array_entry *objects = array->objects;
2109
2110         if (alloc <= nr) {
2111                 unsigned i, j;
2112                 for (i = j = 0; i < nr; i++) {
2113                         if (objects[i].item->flags & SHOWN)
2114                                 continue;
2115                         if (i != j)
2116                                 objects[j] = objects[i];
2117                         j++;
2118                 }
2119                 for (i = j; i < nr; i++)
2120                         objects[i].item = NULL;
2121                 array->nr = j;
2122         }
2123 }
2124
2125 static void create_boundary_commit_list(struct rev_info *revs)
2126 {
2127         unsigned i;
2128         struct commit *c;
2129         struct object_array *array = &revs->boundary_commits;
2130         struct object_array_entry *objects = array->objects;
2131
2132         /*
2133          * If revs->commits is non-NULL at this point, an error occurred in
2134          * get_revision_1().  Ignore the error and continue printing the
2135          * boundary commits anyway.  (This is what the code has always
2136          * done.)
2137          */
2138         if (revs->commits) {
2139                 free_commit_list(revs->commits);
2140                 revs->commits = NULL;
2141         }
2142
2143         /*
2144          * Put all of the actual boundary commits from revs->boundary_commits
2145          * into revs->commits
2146          */
2147         for (i = 0; i < array->nr; i++) {
2148                 c = (struct commit *)(objects[i].item);
2149                 if (!c)
2150                         continue;
2151                 if (!(c->object.flags & CHILD_SHOWN))
2152                         continue;
2153                 if (c->object.flags & (SHOWN | BOUNDARY))
2154                         continue;
2155                 c->object.flags |= BOUNDARY;
2156                 commit_list_insert(c, &revs->commits);
2157         }
2158
2159         /*
2160          * If revs->topo_order is set, sort the boundary commits
2161          * in topological order
2162          */
2163         sort_in_topological_order(&revs->commits, revs->lifo);
2164 }
2165
2166 static struct commit *get_revision_internal(struct rev_info *revs)
2167 {
2168         struct commit *c = NULL;
2169         struct commit_list *l;
2170
2171         if (revs->boundary == 2) {
2172                 /*
2173                  * All of the normal commits have already been returned,
2174                  * and we are now returning boundary commits.
2175                  * create_boundary_commit_list() has populated
2176                  * revs->commits with the remaining commits to return.
2177                  */
2178                 c = pop_commit(&revs->commits);
2179                 if (c)
2180                         c->object.flags |= SHOWN;
2181                 return c;
2182         }
2183
2184         /*
2185          * Now pick up what they want to give us
2186          */
2187         c = get_revision_1(revs);
2188         if (c) {
2189                 while (0 < revs->skip_count) {
2190                         revs->skip_count--;
2191                         c = get_revision_1(revs);
2192                         if (!c)
2193                                 break;
2194                 }
2195         }
2196
2197         /*
2198          * Check the max_count.
2199          */
2200         switch (revs->max_count) {
2201         case -1:
2202                 break;
2203         case 0:
2204                 c = NULL;
2205                 break;
2206         default:
2207                 revs->max_count--;
2208         }
2209
2210         if (c)
2211                 c->object.flags |= SHOWN;
2212
2213         if (!revs->boundary) {
2214                 return c;
2215         }
2216
2217         if (!c) {
2218                 /*
2219                  * get_revision_1() runs out the commits, and
2220                  * we are done computing the boundaries.
2221                  * switch to boundary commits output mode.
2222                  */
2223                 revs->boundary = 2;
2224
2225                 /*
2226                  * Update revs->commits to contain the list of
2227                  * boundary commits.
2228                  */
2229                 create_boundary_commit_list(revs);
2230
2231                 return get_revision_internal(revs);
2232         }
2233
2234         /*
2235          * boundary commits are the commits that are parents of the
2236          * ones we got from get_revision_1() but they themselves are
2237          * not returned from get_revision_1().  Before returning
2238          * 'c', we need to mark its parents that they could be boundaries.
2239          */
2240
2241         for (l = c->parents; l; l = l->next) {
2242                 struct object *p;
2243                 p = &(l->item->object);
2244                 if (p->flags & (CHILD_SHOWN | SHOWN))
2245                         continue;
2246                 p->flags |= CHILD_SHOWN;
2247                 gc_boundary(&revs->boundary_commits);
2248                 add_object_array(p, NULL, &revs->boundary_commits);
2249         }
2250
2251         return c;
2252 }
2253
2254 struct commit *get_revision(struct rev_info *revs)
2255 {
2256         struct commit *c;
2257         struct commit_list *reversed;
2258
2259         if (revs->reverse) {
2260                 reversed = NULL;
2261                 while ((c = get_revision_internal(revs))) {
2262                         commit_list_insert(c, &reversed);
2263                 }
2264                 revs->commits = reversed;
2265                 revs->reverse = 0;
2266                 revs->reverse_output_stage = 1;
2267         }
2268
2269         if (revs->reverse_output_stage)
2270                 return pop_commit(&revs->commits);
2271
2272         c = get_revision_internal(revs);
2273         if (c && revs->graph)
2274                 graph_update(revs->graph, c);
2275         return c;
2276 }
2277
2278 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
2279 {
2280         if (commit->object.flags & BOUNDARY)
2281                 return "-";
2282         else if (commit->object.flags & UNINTERESTING)
2283                 return "^";
2284         else if (commit->object.flags & PATCHSAME)
2285                 return "=";
2286         else if (!revs || revs->left_right) {
2287                 if (commit->object.flags & SYMMETRIC_LEFT)
2288                         return "<";
2289                 else
2290                         return ">";
2291         } else if (revs->graph)
2292                 return "*";
2293         else if (revs->cherry_mark)
2294                 return "+";
2295         return "";
2296 }