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 "grep.h"
  10 #include "reflog-walk.h"
  11 #include "patch-ids.h"
  12
  13 static char *path_name(struct name_path *path, const char *name)
  14 {
  15         struct name_path *p;
  16         char *n, *m;
  17         int nlen = strlen(name);
  18         int len = nlen + 1;
  19
  20         for (p = path; p; p = p->up) {
  21                 if (p->elem_len)
  22                         len += p->elem_len + 1;
  23         }
  24         n = xmalloc(len);
  25         m = n + len - (nlen + 1);
  26         strcpy(m, name);
  27         for (p = path; p; p = p->up) {
  28                 if (p->elem_len) {
  29                         m -= p->elem_len + 1;
  30                         memcpy(m, p->elem, p->elem_len);
  31                         m[p->elem_len] = '/';
  32                 }
  33         }
  34         return n;
  35 }
  36
  37 void add_object(struct object *obj,
  38                 struct object_array *p,
  39                 struct name_path *path,
  40                 const char *name)
  41 {
  42         add_object_array(obj, path_name(path, name), p);
  43 }
  44
  45 static void mark_blob_uninteresting(struct blob *blob)
  46 {
  47         if (blob->object.flags & UNINTERESTING)
  48                 return;
  49         blob->object.flags |= UNINTERESTING;
  50 }
  51
  52 void mark_tree_uninteresting(struct tree *tree)
  53 {
  54         struct tree_desc desc;
  55         struct name_entry entry;
  56         struct object *obj = &tree->object;
  57
  58         if (obj->flags & UNINTERESTING)
  59                 return;
  60         obj->flags |= UNINTERESTING;
  61         if (!has_sha1_file(obj->sha1))
  62                 return;
  63         if (parse_tree(tree) < 0)
  64                 die("bad tree %s", sha1_to_hex(obj->sha1));
  65
  66         init_tree_desc(&desc, tree->buffer, tree->size);
  67         while (tree_entry(&desc, &entry)) {
  68                 if (S_ISDIR(entry.mode))
  69                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  70                 else
  71                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  72         }
  73
  74         /*
  75          * We don't care about the tree any more
  76          * after it has been marked uninteresting.
  77          */
  78         free(tree->buffer);
  79         tree->buffer = NULL;
  80 }
  81
  82 void mark_parents_uninteresting(struct commit *commit)
  83 {
  84         struct commit_list *parents = commit->parents;
  85
  86         while (parents) {
  87                 struct commit *commit = parents->item;
  88                 if (!(commit->object.flags & UNINTERESTING)) {
  89                         commit->object.flags |= UNINTERESTING;
  90
  91                         /*
  92                          * Normally we haven't parsed the parent
  93                          * yet, so we won't have a parent of a parent
  94                          * here. However, it may turn out that we've
  95                          * reached this commit some other way (where it
  96                          * wasn't uninteresting), in which case we need
  97                          * to mark its parents recursively too..
  98                          */
  99                         if (commit->parents)
 100                                 mark_parents_uninteresting(commit);
 101                 }
 102
 103                 /*
 104                  * A missing commit is ok iff its parent is marked
 105                  * uninteresting.
 106                  *
 107                  * We just mark such a thing parsed, so that when
 108                  * it is popped next time around, we won't be trying
 109                  * to parse it and get an error.
 110                  */
 111                 if (!has_sha1_file(commit->object.sha1))
 112                         commit->object.parsed = 1;
 113                 parents = parents->next;
 114         }
 115 }
 116
 117 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 118 {
 119         if (revs->no_walk && (obj->flags & UNINTERESTING))
 120                 die("object ranges do not make sense when not walking revisions");
 121         add_object_array_with_mode(obj, name, &revs->pending, mode);
 122         if (revs->reflog_info && obj->type == OBJ_COMMIT)
 123                 add_reflog_for_walk(revs->reflog_info,
 124                                 (struct commit *)obj, name);
 125 }
 126
 127 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 128 {
 129         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 130 }
 131
 132 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 133 {
 134         struct object *object;
 135
 136         object = parse_object(sha1);
 137         if (!object)
 138                 die("bad object %s", name);
 139         object->flags |= flags;
 140         return object;
 141 }
 142
 143 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 144 {
 145         unsigned long flags = object->flags;
 146
 147         /*
 148          * Tag object? Look what it points to..
 149          */
 150         while (object->type == OBJ_TAG) {
 151                 struct tag *tag = (struct tag *) object;
 152                 if (revs->tag_objects && !(flags & UNINTERESTING))
 153                         add_pending_object(revs, object, tag->tag);
 154                 object = parse_object(tag->tagged->sha1);
 155                 if (!object)
 156                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 157         }
 158
 159         /*
 160          * Commit object? Just return it, we'll do all the complex
 161          * reachability crud.
 162          */
 163         if (object->type == OBJ_COMMIT) {
 164                 struct commit *commit = (struct commit *)object;
 165                 if (parse_commit(commit) < 0)
 166                         die("unable to parse commit %s", name);
 167                 if (flags & UNINTERESTING) {
 168                         commit->object.flags |= UNINTERESTING;
 169                         mark_parents_uninteresting(commit);
 170                         revs->limited = 1;
 171                 }
 172                 return commit;
 173         }
 174
 175         /*
 176          * Tree object? Either mark it uniniteresting, or add it
 177          * to the list of objects to look at later..
 178          */
 179         if (object->type == OBJ_TREE) {
 180                 struct tree *tree = (struct tree *)object;
 181                 if (!revs->tree_objects)
 182                         return NULL;
 183                 if (flags & UNINTERESTING) {
 184                         mark_tree_uninteresting(tree);
 185                         return NULL;
 186                 }
 187                 add_pending_object(revs, object, "");
 188                 return NULL;
 189         }
 190
 191         /*
 192          * Blob object? You know the drill by now..
 193          */
 194         if (object->type == OBJ_BLOB) {
 195                 struct blob *blob = (struct blob *)object;
 196                 if (!revs->blob_objects)
 197                         return NULL;
 198                 if (flags & UNINTERESTING) {
 199                         mark_blob_uninteresting(blob);
 200                         return NULL;
 201                 }
 202                 add_pending_object(revs, object, "");
 203                 return NULL;
 204         }
 205         die("%s is unknown object", name);
 206 }
 207
 208 static int everybody_uninteresting(struct commit_list *orig)
 209 {
 210         struct commit_list *list = orig;
 211         while (list) {
 212                 struct commit *commit = list->item;
 213                 list = list->next;
 214                 if (commit->object.flags & UNINTERESTING)
 215                         continue;
 216                 return 0;
 217         }
 218         return 1;
 219 }
 220
 221 /*
 222  * The goal is to get REV_TREE_NEW as the result only if the
 223  * diff consists of all '+' (and no other changes), and
 224  * REV_TREE_DIFFERENT otherwise (of course if the trees are
 225  * the same we want REV_TREE_SAME).  That means that once we
 226  * get to REV_TREE_DIFFERENT, we do not have to look any further.
 227  */
 228 static int tree_difference = REV_TREE_SAME;
 229
 230 static void file_add_remove(struct diff_options *options,
 231                     int addremove, unsigned mode,
 232                     const unsigned char *sha1,
 233                     const char *base, const char *path)
 234 {
 235         int diff = REV_TREE_DIFFERENT;
 236
 237         /*
 238          * Is it an add of a new file? It means that the old tree
 239          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 240          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 241          * (and if it already was "REV_TREE_NEW", we'll keep it
 242          * "REV_TREE_NEW" of course).
 243          */
 244         if (addremove == '+') {
 245                 diff = tree_difference;
 246                 if (diff != REV_TREE_SAME)
 247                         return;
 248                 diff = REV_TREE_NEW;
 249         }
 250         tree_difference = diff;
 251         if (tree_difference == REV_TREE_DIFFERENT)
 252                 options->has_changes = 1;
 253 }
 254
 255 static void file_change(struct diff_options *options,
 256                  unsigned old_mode, unsigned new_mode,
 257                  const unsigned char *old_sha1,
 258                  const unsigned char *new_sha1,
 259                  const char *base, const char *path)
 260 {
 261         tree_difference = REV_TREE_DIFFERENT;
 262         options->has_changes = 1;
 263 }
 264
 265 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 266 {
 267         if (!t1)
 268                 return REV_TREE_NEW;
 269         if (!t2)
 270                 return REV_TREE_DIFFERENT;
 271         tree_difference = REV_TREE_SAME;
 272         revs->pruning.has_changes = 0;
 273         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 274                            &revs->pruning) < 0)
 275                 return REV_TREE_DIFFERENT;
 276         return tree_difference;
 277 }
 278
 279 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 280 {
 281         int retval;
 282         void *tree;
 283         unsigned long size;
 284         struct tree_desc empty, real;
 285
 286         if (!t1)
 287                 return 0;
 288
 289         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 290         if (!tree)
 291                 return 0;
 292         init_tree_desc(&real, tree, size);
 293         init_tree_desc(&empty, "", 0);
 294
 295         tree_difference = REV_TREE_SAME;
 296         revs->pruning.has_changes = 0;
 297         retval = diff_tree(&empty, &real, "", &revs->pruning);
 298         free(tree);
 299
 300         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 301 }
 302
 303 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 304 {
 305         struct commit_list **pp, *parent;
 306         int tree_changed = 0, tree_same = 0;
 307
 308         if (!commit->tree)
 309                 return;
 310
 311         if (!commit->parents) {
 312                 if (!rev_same_tree_as_empty(revs, commit->tree))
 313                         commit->object.flags |= TREECHANGE;
 314                 return;
 315         }
 316
 317         pp = &commit->parents;
 318         while ((parent = *pp) != NULL) {
 319                 struct commit *p = parent->item;
 320
 321                 if (parse_commit(p) < 0)
 322                         die("cannot simplify commit %s (because of %s)",
 323                             sha1_to_hex(commit->object.sha1),
 324                             sha1_to_hex(p->object.sha1));
 325                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 326                 case REV_TREE_SAME:
 327                         tree_same = 1;
 328                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 329                                 /* Even if a merge with an uninteresting
 330                                  * side branch brought the entire change
 331                                  * we are interested in, we do not want
 332                                  * to lose the other branches of this
 333                                  * merge, so we just keep going.
 334                                  */
 335                                 pp = &parent->next;
 336                                 continue;
 337                         }
 338                         parent->next = NULL;
 339                         commit->parents = parent;
 340                         return;
 341
 342                 case REV_TREE_NEW:
 343                         if (revs->remove_empty_trees &&
 344                             rev_same_tree_as_empty(revs, p->tree)) {
 345                                 /* We are adding all the specified
 346                                  * paths from this parent, so the
 347                                  * history beyond this parent is not
 348                                  * interesting.  Remove its parents
 349                                  * (they are grandparents for us).
 350                                  * IOW, we pretend this parent is a
 351                                  * "root" commit.
 352                                  */
 353                                 if (parse_commit(p) < 0)
 354                                         die("cannot simplify commit %s (invalid %s)",
 355                                             sha1_to_hex(commit->object.sha1),
 356                                             sha1_to_hex(p->object.sha1));
 357                                 p->parents = NULL;
 358                         }
 359                 /* fallthrough */
 360                 case REV_TREE_DIFFERENT:
 361                         tree_changed = 1;
 362                         pp = &parent->next;
 363                         continue;
 364                 }
 365                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 366         }
 367         if (tree_changed && !tree_same)
 368                 commit->object.flags |= TREECHANGE;
 369 }
 370
 371 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 372 {
 373         struct commit_list *parent = commit->parents;
 374         unsigned left_flag;
 375         int add, rest;
 376
 377         if (commit->object.flags & ADDED)
 378                 return 0;
 379         commit->object.flags |= ADDED;
 380
 381         /*
 382          * If the commit is uninteresting, don't try to
 383          * prune parents - we want the maximal uninteresting
 384          * set.
 385          *
 386          * Normally we haven't parsed the parent
 387          * yet, so we won't have a parent of a parent
 388          * here. However, it may turn out that we've
 389          * reached this commit some other way (where it
 390          * wasn't uninteresting), in which case we need
 391          * to mark its parents recursively too..
 392          */
 393         if (commit->object.flags & UNINTERESTING) {
 394                 while (parent) {
 395                         struct commit *p = parent->item;
 396                         parent = parent->next;
 397                         if (parse_commit(p) < 0)
 398                                 return -1;
 399                         p->object.flags |= UNINTERESTING;
 400                         if (p->parents)
 401                                 mark_parents_uninteresting(p);
 402                         if (p->object.flags & SEEN)
 403                                 continue;
 404                         p->object.flags |= SEEN;
 405                         insert_by_date(p, list);
 406                 }
 407                 return 0;
 408         }
 409
 410         /*
 411          * Ok, the commit wasn't uninteresting. Try to
 412          * simplify the commit history and find the parent
 413          * that has no differences in the path set if one exists.
 414          */
 415         if (revs->prune_fn)
 416                 revs->prune_fn(revs, commit);
 417
 418         if (revs->no_walk)
 419                 return 0;
 420
 421         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 422
 423         rest = !revs->first_parent_only;
 424         for (parent = commit->parents, add = 1; parent; add = rest) {
 425                 struct commit *p = parent->item;
 426
 427                 parent = parent->next;
 428                 if (parse_commit(p) < 0)
 429                         return -1;
 430                 p->object.flags |= left_flag;
 431                 if (p->object.flags & SEEN)
 432                         continue;
 433                 p->object.flags |= SEEN;
 434                 if (add)
 435                         insert_by_date(p, list);
 436         }
 437         return 0;
 438 }
 439
 440 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 441 {
 442         struct commit_list *p;
 443         int left_count = 0, right_count = 0;
 444         int left_first;
 445         struct patch_ids ids;
 446
 447         /* First count the commits on the left and on the right */
 448         for (p = list; p; p = p->next) {
 449                 struct commit *commit = p->item;
 450                 unsigned flags = commit->object.flags;
 451                 if (flags & BOUNDARY)
 452                         ;
 453                 else if (flags & SYMMETRIC_LEFT)
 454                         left_count++;
 455                 else
 456                         right_count++;
 457         }
 458
 459         left_first = left_count < right_count;
 460         init_patch_ids(&ids);
 461         if (revs->diffopt.nr_paths) {
 462                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 463                 ids.diffopts.paths = revs->diffopt.paths;
 464                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 465         }
 466
 467         /* Compute patch-ids for one side */
 468         for (p = list; p; p = p->next) {
 469                 struct commit *commit = p->item;
 470                 unsigned flags = commit->object.flags;
 471
 472                 if (flags & BOUNDARY)
 473                         continue;
 474                 /*
 475                  * If we have fewer left, left_first is set and we omit
 476                  * commits on the right branch in this loop.  If we have
 477                  * fewer right, we skip the left ones.
 478                  */
 479                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 480                         continue;
 481                 commit->util = add_commit_patch_id(commit, &ids);
 482         }
 483
 484         /* Check the other side */
 485         for (p = list; p; p = p->next) {
 486                 struct commit *commit = p->item;
 487                 struct patch_id *id;
 488                 unsigned flags = commit->object.flags;
 489
 490                 if (flags & BOUNDARY)
 491                         continue;
 492                 /*
 493                  * If we have fewer left, left_first is set and we omit
 494                  * commits on the left branch in this loop.
 495                  */
 496                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 497                         continue;
 498
 499                 /*
 500                  * Have we seen the same patch id?
 501                  */
 502                 id = has_commit_patch_id(commit, &ids);
 503                 if (!id)
 504                         continue;
 505                 id->seen = 1;
 506                 commit->object.flags |= SHOWN;
 507         }
 508
 509         /* Now check the original side for seen ones */
 510         for (p = list; p; p = p->next) {
 511                 struct commit *commit = p->item;
 512                 struct patch_id *ent;
 513
 514                 ent = commit->util;
 515                 if (!ent)
 516                         continue;
 517                 if (ent->seen)
 518                         commit->object.flags |= SHOWN;
 519                 commit->util = NULL;
 520         }
 521
 522         free_patch_ids(&ids);
 523 }
 524
 525 static int limit_list(struct rev_info *revs)
 526 {
 527         struct commit_list *list = revs->commits;
 528         struct commit_list *newlist = NULL;
 529         struct commit_list **p = &newlist;
 530
 531         while (list) {
 532                 struct commit_list *entry = list;
 533                 struct commit *commit = list->item;
 534                 struct object *obj = &commit->object;
 535
 536                 list = list->next;
 537                 free(entry);
 538
 539                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 540                         obj->flags |= UNINTERESTING;
 541                 if (add_parents_to_list(revs, commit, &list) < 0)
 542                         return -1;
 543                 if (obj->flags & UNINTERESTING) {
 544                         mark_parents_uninteresting(commit);
 545                         if (everybody_uninteresting(list))
 546                                 break;
 547                         continue;
 548                 }
 549                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 550                         continue;
 551                 p = &commit_list_insert(commit, p)->next;
 552         }
 553         if (revs->cherry_pick)
 554                 cherry_pick_list(newlist, revs);
 555
 556         revs->commits = newlist;
 557         return 0;
 558 }
 559
 560 struct all_refs_cb {
 561         int all_flags;
 562         int warned_bad_reflog;
 563         struct rev_info *all_revs;
 564         const char *name_for_errormsg;
 565 };
 566
 567 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 568 {
 569         struct all_refs_cb *cb = cb_data;
 570         struct object *object = get_reference(cb->all_revs, path, sha1,
 571                                               cb->all_flags);
 572         add_pending_object(cb->all_revs, object, path);
 573         return 0;
 574 }
 575
 576 static void handle_all(struct rev_info *revs, unsigned flags)
 577 {
 578         struct all_refs_cb cb;
 579         cb.all_revs = revs;
 580         cb.all_flags = flags;
 581         for_each_ref(handle_one_ref, &cb);
 582 }
 583
 584 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 585 {
 586         struct all_refs_cb *cb = cb_data;
 587         if (!is_null_sha1(sha1)) {
 588                 struct object *o = parse_object(sha1);
 589                 if (o) {
 590                         o->flags |= cb->all_flags;
 591                         add_pending_object(cb->all_revs, o, "");
 592                 }
 593                 else if (!cb->warned_bad_reflog) {
 594                         warning("reflog of '%s' references pruned commits",
 595                                 cb->name_for_errormsg);
 596                         cb->warned_bad_reflog = 1;
 597                 }
 598         }
 599 }
 600
 601 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 602                 const char *email, unsigned long timestamp, int tz,
 603                 const char *message, void *cb_data)
 604 {
 605         handle_one_reflog_commit(osha1, cb_data);
 606         handle_one_reflog_commit(nsha1, cb_data);
 607         return 0;
 608 }
 609
 610 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 611 {
 612         struct all_refs_cb *cb = cb_data;
 613         cb->warned_bad_reflog = 0;
 614         cb->name_for_errormsg = path;
 615         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 616         return 0;
 617 }
 618
 619 static void handle_reflog(struct rev_info *revs, unsigned flags)
 620 {
 621         struct all_refs_cb cb;
 622         cb.all_revs = revs;
 623         cb.all_flags = flags;
 624         for_each_reflog(handle_one_reflog, &cb);
 625 }
 626
 627 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 628 {
 629         unsigned char sha1[20];
 630         struct object *it;
 631         struct commit *commit;
 632         struct commit_list *parents;
 633
 634         if (*arg == '^') {
 635                 flags ^= UNINTERESTING;
 636                 arg++;
 637         }
 638         if (get_sha1(arg, sha1))
 639                 return 0;
 640         while (1) {
 641                 it = get_reference(revs, arg, sha1, 0);
 642                 if (it->type != OBJ_TAG)
 643                         break;
 644                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 645         }
 646         if (it->type != OBJ_COMMIT)
 647                 return 0;
 648         commit = (struct commit *)it;
 649         for (parents = commit->parents; parents; parents = parents->next) {
 650                 it = &parents->item->object;
 651                 it->flags |= flags;
 652                 add_pending_object(revs, it, arg);
 653         }
 654         return 1;
 655 }
 656
 657 void init_revisions(struct rev_info *revs, const char *prefix)
 658 {
 659         memset(revs, 0, sizeof(*revs));
 660
 661         revs->abbrev = DEFAULT_ABBREV;
 662         revs->ignore_merges = 1;
 663         revs->simplify_history = 1;
 664         revs->pruning.recursive = 1;
 665         revs->pruning.quiet = 1;
 666         revs->pruning.add_remove = file_add_remove;
 667         revs->pruning.change = file_change;
 668         revs->lifo = 1;
 669         revs->dense = 1;
 670         revs->prefix = prefix;
 671         revs->max_age = -1;
 672         revs->min_age = -1;
 673         revs->skip_count = -1;
 674         revs->max_count = -1;
 675
 676         revs->prune_fn = NULL;
 677         revs->prune_data = NULL;
 678
 679         revs->topo_setter = topo_sort_default_setter;
 680         revs->topo_getter = topo_sort_default_getter;
 681
 682         revs->commit_format = CMIT_FMT_DEFAULT;
 683
 684         diff_setup(&revs->diffopt);
 685 }
 686
 687 static void add_pending_commit_list(struct rev_info *revs,
 688                                     struct commit_list *commit_list,
 689                                     unsigned int flags)
 690 {
 691         while (commit_list) {
 692                 struct object *object = &commit_list->item->object;
 693                 object->flags |= flags;
 694                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 695                 commit_list = commit_list->next;
 696         }
 697 }
 698
 699 static void prepare_show_merge(struct rev_info *revs)
 700 {
 701         struct commit_list *bases;
 702         struct commit *head, *other;
 703         unsigned char sha1[20];
 704         const char **prune = NULL;
 705         int i, prune_num = 1; /* counting terminating NULL */
 706
 707         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 708                 die("--merge without HEAD?");
 709         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 710                 die("--merge without MERGE_HEAD?");
 711         add_pending_object(revs, &head->object, "HEAD");
 712         add_pending_object(revs, &other->object, "MERGE_HEAD");
 713         bases = get_merge_bases(head, other, 1);
 714         while (bases) {
 715                 struct commit *it = bases->item;
 716                 struct commit_list *n = bases->next;
 717                 free(bases);
 718                 bases = n;
 719                 it->object.flags |= UNINTERESTING;
 720                 add_pending_object(revs, &it->object, "(merge-base)");
 721         }
 722
 723         if (!active_nr)
 724                 read_cache();
 725         for (i = 0; i < active_nr; i++) {
 726                 struct cache_entry *ce = active_cache[i];
 727                 if (!ce_stage(ce))
 728                         continue;
 729                 if (ce_path_match(ce, revs->prune_data)) {
 730                         prune_num++;
 731                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 732                         prune[prune_num-2] = ce->name;
 733                         prune[prune_num-1] = NULL;
 734                 }
 735                 while ((i+1 < active_nr) &&
 736                        ce_same_name(ce, active_cache[i+1]))
 737                         i++;
 738         }
 739         revs->prune_data = prune;
 740 }
 741
 742 int handle_revision_arg(const char *arg, struct rev_info *revs,
 743                         int flags,
 744                         int cant_be_filename)
 745 {
 746         unsigned mode;
 747         char *dotdot;
 748         struct object *object;
 749         unsigned char sha1[20];
 750         int local_flags;
 751
 752         dotdot = strstr(arg, "..");
 753         if (dotdot) {
 754                 unsigned char from_sha1[20];
 755                 const char *next = dotdot + 2;
 756                 const char *this = arg;
 757                 int symmetric = *next == '.';
 758                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 759
 760                 *dotdot = 0;
 761                 next += symmetric;
 762
 763                 if (!*next)
 764                         next = "HEAD";
 765                 if (dotdot == arg)
 766                         this = "HEAD";
 767                 if (!get_sha1(this, from_sha1) &&
 768                     !get_sha1(next, sha1)) {
 769                         struct commit *a, *b;
 770                         struct commit_list *exclude;
 771
 772                         a = lookup_commit_reference(from_sha1);
 773                         b = lookup_commit_reference(sha1);
 774                         if (!a || !b) {
 775                                 die(symmetric ?
 776                                     "Invalid symmetric difference expression %s...%s" :
 777                                     "Invalid revision range %s..%s",
 778                                     arg, next);
 779                         }
 780
 781                         if (!cant_be_filename) {
 782                                 *dotdot = '.';
 783                                 verify_non_filename(revs->prefix, arg);
 784                         }
 785
 786                         if (symmetric) {
 787                                 exclude = get_merge_bases(a, b, 1);
 788                                 add_pending_commit_list(revs, exclude,
 789                                                         flags_exclude);
 790                                 free_commit_list(exclude);
 791                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 792                         } else
 793                                 a->object.flags |= flags_exclude;
 794                         b->object.flags |= flags;
 795                         add_pending_object(revs, &a->object, this);
 796                         add_pending_object(revs, &b->object, next);
 797                         return 0;
 798                 }
 799                 *dotdot = '.';
 800         }
 801         dotdot = strstr(arg, "^@");
 802         if (dotdot && !dotdot[2]) {
 803                 *dotdot = 0;
 804                 if (add_parents_only(revs, arg, flags))
 805                         return 0;
 806                 *dotdot = '^';
 807         }
 808         dotdot = strstr(arg, "^!");
 809         if (dotdot && !dotdot[2]) {
 810                 *dotdot = 0;
 811                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 812                         *dotdot = '^';
 813         }
 814
 815         local_flags = 0;
 816         if (*arg == '^') {
 817                 local_flags = UNINTERESTING;
 818                 arg++;
 819         }
 820         if (get_sha1_with_mode(arg, sha1, &mode))
 821                 return -1;
 822         if (!cant_be_filename)
 823                 verify_non_filename(revs->prefix, arg);
 824         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 825         add_pending_object_with_mode(revs, object, arg, mode);
 826         return 0;
 827 }
 828
 829 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 830 {
 831         if (!revs->grep_filter) {
 832                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 833                 opt->status_only = 1;
 834                 opt->pattern_tail = &(opt->pattern_list);
 835                 opt->regflags = REG_NEWLINE;
 836                 revs->grep_filter = opt;
 837         }
 838         append_grep_pattern(revs->grep_filter, ptn,
 839                             "command line", 0, what);
 840 }
 841
 842 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 843 {
 844         char *pat;
 845         const char *prefix;
 846         int patlen, fldlen;
 847
 848         fldlen = strlen(field);
 849         patlen = strlen(pattern);
 850         pat = xmalloc(patlen + fldlen + 10);
 851         prefix = ".*";
 852         if (*pattern == '^') {
 853                 prefix = "";
 854                 pattern++;
 855         }
 856         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 857         add_grep(revs, pat, GREP_PATTERN_HEAD);
 858 }
 859
 860 static void add_message_grep(struct rev_info *revs, const char *pattern)
 861 {
 862         add_grep(revs, pattern, GREP_PATTERN_BODY);
 863 }
 864
 865 static void add_ignore_packed(struct rev_info *revs, const char *name)
 866 {
 867         int num = ++revs->num_ignore_packed;
 868
 869         revs->ignore_packed = xrealloc(revs->ignore_packed,
 870                                        sizeof(const char **) * (num + 1));
 871         revs->ignore_packed[num-1] = name;
 872         revs->ignore_packed[num] = NULL;
 873 }
 874
 875 /*
 876  * Parse revision information, filling in the "rev_info" structure,
 877  * and removing the used arguments from the argument list.
 878  *
 879  * Returns the number of arguments left that weren't recognized
 880  * (which are also moved to the head of the argument list)
 881  */
 882 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 883 {
 884         int i, flags, seen_dashdash, show_merge;
 885         const char **unrecognized = argv + 1;
 886         int left = 1;
 887         int all_match = 0;
 888         int regflags = 0;
 889
 890         /* First, search for "--" */
 891         seen_dashdash = 0;
 892         for (i = 1; i < argc; i++) {
 893                 const char *arg = argv[i];
 894                 if (strcmp(arg, "--"))
 895                         continue;
 896                 argv[i] = NULL;
 897                 argc = i;
 898                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 899                 seen_dashdash = 1;
 900                 break;
 901         }
 902
 903         flags = show_merge = 0;
 904         for (i = 1; i < argc; i++) {
 905                 const char *arg = argv[i];
 906                 if (*arg == '-') {
 907                         int opts;
 908                         if (!prefixcmp(arg, "--max-count=")) {
 909                                 revs->max_count = atoi(arg + 12);
 910                                 continue;
 911                         }
 912                         if (!prefixcmp(arg, "--skip=")) {
 913                                 revs->skip_count = atoi(arg + 7);
 914                                 continue;
 915                         }
 916                         /* accept -<digit>, like traditional "head" */
 917                         if ((*arg == '-') && isdigit(arg[1])) {
 918                                 revs->max_count = atoi(arg + 1);
 919                                 continue;
 920                         }
 921                         if (!strcmp(arg, "-n")) {
 922                                 if (argc <= i + 1)
 923                                         die("-n requires an argument");
 924                                 revs->max_count = atoi(argv[++i]);
 925                                 continue;
 926                         }
 927                         if (!prefixcmp(arg, "-n")) {
 928                                 revs->max_count = atoi(arg + 2);
 929                                 continue;
 930                         }
 931                         if (!prefixcmp(arg, "--max-age=")) {
 932                                 revs->max_age = atoi(arg + 10);
 933                                 continue;
 934                         }
 935                         if (!prefixcmp(arg, "--since=")) {
 936                                 revs->max_age = approxidate(arg + 8);
 937                                 continue;
 938                         }
 939                         if (!prefixcmp(arg, "--after=")) {
 940                                 revs->max_age = approxidate(arg + 8);
 941                                 continue;
 942                         }
 943                         if (!prefixcmp(arg, "--min-age=")) {
 944                                 revs->min_age = atoi(arg + 10);
 945                                 continue;
 946                         }
 947                         if (!prefixcmp(arg, "--before=")) {
 948                                 revs->min_age = approxidate(arg + 9);
 949                                 continue;
 950                         }
 951                         if (!prefixcmp(arg, "--until=")) {
 952                                 revs->min_age = approxidate(arg + 8);
 953                                 continue;
 954                         }
 955                         if (!strcmp(arg, "--all")) {
 956                                 handle_all(revs, flags);
 957                                 continue;
 958                         }
 959                         if (!strcmp(arg, "--first-parent")) {
 960                                 revs->first_parent_only = 1;
 961                                 continue;
 962                         }
 963                         if (!strcmp(arg, "--reflog")) {
 964                                 handle_reflog(revs, flags);
 965                                 continue;
 966                         }
 967                         if (!strcmp(arg, "-g") ||
 968                                         !strcmp(arg, "--walk-reflogs")) {
 969                                 init_reflog_walk(&revs->reflog_info);
 970                                 continue;
 971                         }
 972                         if (!strcmp(arg, "--not")) {
 973                                 flags ^= UNINTERESTING;
 974                                 continue;
 975                         }
 976                         if (!strcmp(arg, "--default")) {
 977                                 if (++i >= argc)
 978                                         die("bad --default argument");
 979                                 def = argv[i];
 980                                 continue;
 981                         }
 982                         if (!strcmp(arg, "--merge")) {
 983                                 show_merge = 1;
 984                                 continue;
 985                         }
 986                         if (!strcmp(arg, "--topo-order")) {
 987                                 revs->topo_order = 1;
 988                                 continue;
 989                         }
 990                         if (!strcmp(arg, "--date-order")) {
 991                                 revs->lifo = 0;
 992                                 revs->topo_order = 1;
 993                                 continue;
 994                         }
 995                         if (!strcmp(arg, "--parents")) {
 996                                 revs->parents = 1;
 997                                 continue;
 998                         }
 999                         if (!strcmp(arg, "--dense")) {
1000                                 revs->dense = 1;
1001                                 continue;
1002                         }
1003                         if (!strcmp(arg, "--sparse")) {
1004                                 revs->dense = 0;
1005                                 continue;
1006                         }
1007                         if (!strcmp(arg, "--remove-empty")) {
1008                                 revs->remove_empty_trees = 1;
1009                                 continue;
1010                         }
1011                         if (!strcmp(arg, "--no-merges")) {
1012                                 revs->no_merges = 1;
1013                                 continue;
1014                         }
1015                         if (!strcmp(arg, "--boundary")) {
1016                                 revs->boundary = 1;
1017                                 continue;
1018                         }
1019                         if (!strcmp(arg, "--left-right")) {
1020                                 revs->left_right = 1;
1021                                 continue;
1022                         }
1023                         if (!strcmp(arg, "--cherry-pick")) {
1024                                 revs->cherry_pick = 1;
1025                                 continue;
1026                         }
1027                         if (!strcmp(arg, "--objects")) {
1028                                 revs->tag_objects = 1;
1029                                 revs->tree_objects = 1;
1030                                 revs->blob_objects = 1;
1031                                 continue;
1032                         }
1033                         if (!strcmp(arg, "--objects-edge")) {
1034                                 revs->tag_objects = 1;
1035                                 revs->tree_objects = 1;
1036                                 revs->blob_objects = 1;
1037                                 revs->edge_hint = 1;
1038                                 continue;
1039                         }
1040                         if (!strcmp(arg, "--unpacked")) {
1041                                 revs->unpacked = 1;
1042                                 free(revs->ignore_packed);
1043                                 revs->ignore_packed = NULL;
1044                                 revs->num_ignore_packed = 0;
1045                                 continue;
1046                         }
1047                         if (!prefixcmp(arg, "--unpacked=")) {
1048                                 revs->unpacked = 1;
1049                                 add_ignore_packed(revs, arg+11);
1050                                 continue;
1051                         }
1052                         if (!strcmp(arg, "-r")) {
1053                                 revs->diff = 1;
1054                                 revs->diffopt.recursive = 1;
1055                                 continue;
1056                         }
1057                         if (!strcmp(arg, "-t")) {
1058                                 revs->diff = 1;
1059                                 revs->diffopt.recursive = 1;
1060                                 revs->diffopt.tree_in_recursive = 1;
1061                                 continue;
1062                         }
1063                         if (!strcmp(arg, "-m")) {
1064                                 revs->ignore_merges = 0;
1065                                 continue;
1066                         }
1067                         if (!strcmp(arg, "-c")) {
1068                                 revs->diff = 1;
1069                                 revs->dense_combined_merges = 0;
1070                                 revs->combine_merges = 1;
1071                                 continue;
1072                         }
1073                         if (!strcmp(arg, "--cc")) {
1074                                 revs->diff = 1;
1075                                 revs->dense_combined_merges = 1;
1076                                 revs->combine_merges = 1;
1077                                 continue;
1078                         }
1079                         if (!strcmp(arg, "-v")) {
1080                                 revs->verbose_header = 1;
1081                                 continue;
1082                         }
1083                         if (!prefixcmp(arg, "--pretty")) {
1084                                 revs->verbose_header = 1;
1085                                 revs->commit_format = get_commit_format(arg+8);
1086                                 continue;
1087                         }
1088                         if (!strcmp(arg, "--root")) {
1089                                 revs->show_root_diff = 1;
1090                                 continue;
1091                         }
1092                         if (!strcmp(arg, "--no-commit-id")) {
1093                                 revs->no_commit_id = 1;
1094                                 continue;
1095                         }
1096                         if (!strcmp(arg, "--always")) {
1097                                 revs->always_show_header = 1;
1098                                 continue;
1099                         }
1100                         if (!strcmp(arg, "--no-abbrev")) {
1101                                 revs->abbrev = 0;
1102                                 continue;
1103                         }
1104                         if (!strcmp(arg, "--abbrev")) {
1105                                 revs->abbrev = DEFAULT_ABBREV;
1106                                 continue;
1107                         }
1108                         if (!prefixcmp(arg, "--abbrev=")) {
1109                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1110                                 if (revs->abbrev < MINIMUM_ABBREV)
1111                                         revs->abbrev = MINIMUM_ABBREV;
1112                                 else if (revs->abbrev > 40)
1113                                         revs->abbrev = 40;
1114                                 continue;
1115                         }
1116                         if (!strcmp(arg, "--abbrev-commit")) {
1117                                 revs->abbrev_commit = 1;
1118                                 continue;
1119                         }
1120                         if (!strcmp(arg, "--full-diff")) {
1121                                 revs->diff = 1;
1122                                 revs->full_diff = 1;
1123                                 continue;
1124                         }
1125                         if (!strcmp(arg, "--full-history")) {
1126                                 revs->simplify_history = 0;
1127                                 continue;
1128                         }
1129                         if (!strcmp(arg, "--relative-date")) {
1130                                 revs->date_mode = DATE_RELATIVE;
1131                                 continue;
1132                         }
1133                         if (!strncmp(arg, "--date=", 7)) {
1134                                 if (!strcmp(arg + 7, "relative"))
1135                                         revs->date_mode = DATE_RELATIVE;
1136                                 else if (!strcmp(arg + 7, "iso8601") ||
1137                                          !strcmp(arg + 7, "iso"))
1138                                         revs->date_mode = DATE_ISO8601;
1139                                 else if (!strcmp(arg + 7, "rfc2822") ||
1140                                          !strcmp(arg + 7, "rfc"))
1141                                         revs->date_mode = DATE_RFC2822;
1142                                 else if (!strcmp(arg + 7, "short"))
1143                                         revs->date_mode = DATE_SHORT;
1144                                 else if (!strcmp(arg + 7, "local"))
1145                                         revs->date_mode = DATE_LOCAL;
1146                                 else if (!strcmp(arg + 7, "default"))
1147                                         revs->date_mode = DATE_NORMAL;
1148                                 else
1149                                         die("unknown date format %s", arg);
1150                                 continue;
1151                         }
1152
1153                         /*
1154                          * Grepping the commit log
1155                          */
1156                         if (!prefixcmp(arg, "--author=")) {
1157                                 add_header_grep(revs, "author", arg+9);
1158                                 continue;
1159                         }
1160                         if (!prefixcmp(arg, "--committer=")) {
1161                                 add_header_grep(revs, "committer", arg+12);
1162                                 continue;
1163                         }
1164                         if (!prefixcmp(arg, "--grep=")) {
1165                                 add_message_grep(revs, arg+7);
1166                                 continue;
1167                         }
1168                         if (!strcmp(arg, "--extended-regexp") ||
1169                             !strcmp(arg, "-E")) {
1170                                 regflags |= REG_EXTENDED;
1171                                 continue;
1172                         }
1173                         if (!strcmp(arg, "--regexp-ignore-case") ||
1174                             !strcmp(arg, "-i")) {
1175                                 regflags |= REG_ICASE;
1176                                 continue;
1177                         }
1178                         if (!strcmp(arg, "--all-match")) {
1179                                 all_match = 1;
1180                                 continue;
1181                         }
1182                         if (!prefixcmp(arg, "--encoding=")) {
1183                                 arg += 11;
1184                                 if (strcmp(arg, "none"))
1185                                         git_log_output_encoding = xstrdup(arg);
1186                                 else
1187                                         git_log_output_encoding = "";
1188                                 continue;
1189                         }
1190                         if (!strcmp(arg, "--reverse")) {
1191                                 revs->reverse ^= 1;
1192                                 continue;
1193                         }
1194
1195                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1196                         if (opts > 0) {
1197                                 if (strcmp(argv[i], "-z"))
1198                                         revs->diff = 1;
1199                                 i += opts - 1;
1200                                 continue;
1201                         }
1202                         *unrecognized++ = arg;
1203                         left++;
1204                         continue;
1205                 }
1206
1207                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1208                         int j;
1209                         if (seen_dashdash || *arg == '^')
1210                                 die("bad revision '%s'", arg);
1211
1212                         /* If we didn't have a "--":
1213                          * (1) all filenames must exist;
1214                          * (2) all rev-args must not be interpretable
1215                          *     as a valid filename.
1216                          * but the latter we have checked in the main loop.
1217                          */
1218                         for (j = i; j < argc; j++)
1219                                 verify_filename(revs->prefix, argv[j]);
1220
1221                         revs->prune_data = get_pathspec(revs->prefix,
1222                                                         argv + i);
1223                         break;
1224                 }
1225         }
1226
1227         if (revs->grep_filter)
1228                 revs->grep_filter->regflags |= regflags;
1229
1230         if (show_merge)
1231                 prepare_show_merge(revs);
1232         if (def && !revs->pending.nr) {
1233                 unsigned char sha1[20];
1234                 struct object *object;
1235                 unsigned mode;
1236                 if (get_sha1_with_mode(def, sha1, &mode))
1237                         die("bad default revision '%s'", def);
1238                 object = get_reference(revs, def, sha1, 0);
1239                 add_pending_object_with_mode(revs, object, def, mode);
1240         }
1241
1242         if (revs->topo_order)
1243                 revs->limited = 1;
1244
1245         if (revs->prune_data) {
1246                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1247                 /* Can't prune commits with rename following: the paths change.. */
1248                 if (!revs->diffopt.follow_renames)
1249                         revs->prune_fn = try_to_simplify_commit;
1250                 if (!revs->full_diff)
1251                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1252         }
1253         if (revs->combine_merges) {
1254                 revs->ignore_merges = 0;
1255                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1256                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1257         }
1258         revs->diffopt.abbrev = revs->abbrev;
1259         if (diff_setup_done(&revs->diffopt) < 0)
1260                 die("diff_setup_done failed");
1261
1262         if (revs->grep_filter) {
1263                 revs->grep_filter->all_match = all_match;
1264                 compile_grep_patterns(revs->grep_filter);
1265         }
1266
1267         return left;
1268 }
1269
1270 int prepare_revision_walk(struct rev_info *revs)
1271 {
1272         int nr = revs->pending.nr;
1273         struct object_array_entry *e, *list;
1274
1275         e = list = revs->pending.objects;
1276         revs->pending.nr = 0;
1277         revs->pending.alloc = 0;
1278         revs->pending.objects = NULL;
1279         while (--nr >= 0) {
1280                 struct commit *commit = handle_commit(revs, e->item, e->name);
1281                 if (commit) {
1282                         if (!(commit->object.flags & SEEN)) {
1283                                 commit->object.flags |= SEEN;
1284                                 insert_by_date(commit, &revs->commits);
1285                         }
1286                 }
1287                 e++;
1288         }
1289         free(list);
1290
1291         if (revs->no_walk)
1292                 return 0;
1293         if (revs->limited)
1294                 if (limit_list(revs) < 0)
1295                         return -1;
1296         if (revs->topo_order)
1297                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
1298                                              revs->topo_setter,
1299                                              revs->topo_getter);
1300         return 0;
1301 }
1302
1303 enum rewrite_result {
1304         rewrite_one_ok,
1305         rewrite_one_noparents,
1306         rewrite_one_error,
1307 };
1308
1309 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1310 {
1311         for (;;) {
1312                 struct commit *p = *pp;
1313                 if (!revs->limited)
1314                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1315                                 return rewrite_one_error;
1316                 if (p->parents && p->parents->next)
1317                         return rewrite_one_ok;
1318                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
1319                         return rewrite_one_ok;
1320                 if (!p->parents)
1321                         return rewrite_one_noparents;
1322                 *pp = p->parents->item;
1323         }
1324 }
1325
1326 static void remove_duplicate_parents(struct commit *commit)
1327 {
1328         struct commit_list **pp, *p;
1329
1330         /* Examine existing parents while marking ones we have seen... */
1331         pp = &commit->parents;
1332         while ((p = *pp) != NULL) {
1333                 struct commit *parent = p->item;
1334                 if (parent->object.flags & TMP_MARK) {
1335                         *pp = p->next;
1336                         continue;
1337                 }
1338                 parent->object.flags |= TMP_MARK;
1339                 pp = &p->next;
1340         }
1341         /* ... and clear the temporary mark */
1342         for (p = commit->parents; p; p = p->next)
1343                 p->item->object.flags &= ~TMP_MARK;
1344 }
1345
1346 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1347 {
1348         struct commit_list **pp = &commit->parents;
1349         while (*pp) {
1350                 struct commit_list *parent = *pp;
1351                 switch (rewrite_one(revs, &parent->item)) {
1352                 case rewrite_one_ok:
1353                         break;
1354                 case rewrite_one_noparents:
1355                         *pp = parent->next;
1356                         continue;
1357                 case rewrite_one_error:
1358                         return -1;
1359                 }
1360                 pp = &parent->next;
1361         }
1362         remove_duplicate_parents(commit);
1363         return 0;
1364 }
1365
1366 static int commit_match(struct commit *commit, struct rev_info *opt)
1367 {
1368         if (!opt->grep_filter)
1369                 return 1;
1370         return grep_buffer(opt->grep_filter,
1371                            NULL, /* we say nothing, not even filename */
1372                            commit->buffer, strlen(commit->buffer));
1373 }
1374
1375 static struct commit *get_revision_1(struct rev_info *revs)
1376 {
1377         if (!revs->commits)
1378                 return NULL;
1379
1380         do {
1381                 struct commit_list *entry = revs->commits;
1382                 struct commit *commit = entry->item;
1383
1384                 revs->commits = entry->next;
1385                 free(entry);
1386
1387                 if (revs->reflog_info)
1388                         fake_reflog_parent(revs->reflog_info, commit);
1389
1390                 /*
1391                  * If we haven't done the list limiting, we need to look at
1392                  * the parents here. We also need to do the date-based limiting
1393                  * that we'd otherwise have done in limit_list().
1394                  */
1395                 if (!revs->limited) {
1396                         if (revs->max_age != -1 &&
1397                             (commit->date < revs->max_age))
1398                                 continue;
1399                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1400                                 return NULL;
1401                 }
1402                 if (commit->object.flags & SHOWN)
1403                         continue;
1404
1405                 if (revs->unpacked && has_sha1_pack(commit->object.sha1,
1406                                                     revs->ignore_packed))
1407                     continue;
1408
1409                 if (commit->object.flags & UNINTERESTING)
1410                         continue;
1411                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1412                         continue;
1413                 if (revs->no_merges &&
1414                     commit->parents && commit->parents->next)
1415                         continue;
1416                 if (!commit_match(commit, revs))
1417                         continue;
1418                 if (revs->prune_fn && revs->dense) {
1419                         /* Commit without changes? */
1420                         if (!(commit->object.flags & TREECHANGE)) {
1421                                 /* drop merges unless we want parenthood */
1422                                 if (!revs->parents)
1423                                         continue;
1424                                 /* non-merge - always ignore it */
1425                                 if (!commit->parents || !commit->parents->next)
1426                                         continue;
1427                         }
1428                         if (revs->parents && rewrite_parents(revs, commit) < 0)
1429                                 return NULL;
1430                 }
1431                 return commit;
1432         } while (revs->commits);
1433         return NULL;
1434 }
1435
1436 static void gc_boundary(struct object_array *array)
1437 {
1438         unsigned nr = array->nr;
1439         unsigned alloc = array->alloc;
1440         struct object_array_entry *objects = array->objects;
1441
1442         if (alloc <= nr) {
1443                 unsigned i, j;
1444                 for (i = j = 0; i < nr; i++) {
1445                         if (objects[i].item->flags & SHOWN)
1446                                 continue;
1447                         if (i != j)
1448                                 objects[j] = objects[i];
1449                         j++;
1450                 }
1451                 for (i = j; i < nr; i++)
1452                         objects[i].item = NULL;
1453                 array->nr = j;
1454         }
1455 }
1456
1457 struct commit *get_revision(struct rev_info *revs)
1458 {
1459         struct commit *c = NULL;
1460         struct commit_list *l;
1461
1462         if (revs->boundary == 2) {
1463                 unsigned i;
1464                 struct object_array *array = &revs->boundary_commits;
1465                 struct object_array_entry *objects = array->objects;
1466                 for (i = 0; i < array->nr; i++) {
1467                         c = (struct commit *)(objects[i].item);
1468                         if (!c)
1469                                 continue;
1470                         if (!(c->object.flags & CHILD_SHOWN))
1471                                 continue;
1472                         if (!(c->object.flags & SHOWN))
1473                                 break;
1474                 }
1475                 if (array->nr <= i)
1476                         return NULL;
1477
1478                 c->object.flags |= SHOWN | BOUNDARY;
1479                 return c;
1480         }
1481
1482         if (revs->reverse) {
1483                 int limit = -1;
1484
1485                 if (0 <= revs->max_count) {
1486                         limit = revs->max_count;
1487                         if (0 < revs->skip_count)
1488                                 limit += revs->skip_count;
1489                 }
1490                 l = NULL;
1491                 while ((c = get_revision_1(revs))) {
1492                         commit_list_insert(c, &l);
1493                         if ((0 < limit) && !--limit)
1494                                 break;
1495                 }
1496                 revs->commits = l;
1497                 revs->reverse = 0;
1498                 revs->max_count = -1;
1499                 c = NULL;
1500         }
1501
1502         /*
1503          * Now pick up what they want to give us
1504          */
1505         c = get_revision_1(revs);
1506         if (c) {
1507                 while (0 < revs->skip_count) {
1508                         revs->skip_count--;
1509                         c = get_revision_1(revs);
1510                         if (!c)
1511                                 break;
1512                 }
1513         }
1514
1515         /*
1516          * Check the max_count.
1517          */
1518         switch (revs->max_count) {
1519         case -1:
1520                 break;
1521         case 0:
1522                 c = NULL;
1523                 break;
1524         default:
1525                 revs->max_count--;
1526         }
1527
1528         if (c)
1529                 c->object.flags |= SHOWN;
1530
1531         if (!revs->boundary) {
1532                 return c;
1533         }
1534
1535         if (!c) {
1536                 /*
1537                  * get_revision_1() runs out the commits, and
1538                  * we are done computing the boundaries.
1539                  * switch to boundary commits output mode.
1540                  */
1541                 revs->boundary = 2;
1542                 return get_revision(revs);
1543         }
1544
1545         /*
1546          * boundary commits are the commits that are parents of the
1547          * ones we got from get_revision_1() but they themselves are
1548          * not returned from get_revision_1().  Before returning
1549          * 'c', we need to mark its parents that they could be boundaries.
1550          */
1551
1552         for (l = c->parents; l; l = l->next) {
1553                 struct object *p;
1554                 p = &(l->item->object);
1555                 if (p->flags & (CHILD_SHOWN | SHOWN))
1556                         continue;
1557                 p->flags |= CHILD_SHOWN;
1558                 gc_boundary(&revs->boundary_commits);
1559                 add_object_array(p, NULL, &revs->boundary_commits);
1560         }
1561
1562         return c;
1563 }