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         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 122                         add_reflog_for_walk(revs->reflog_info,
 123                                 (struct commit *)obj, name))
 124                 return;
 125         add_object_array_with_mode(obj, name, &revs->pending, mode);
 126 }
 127
 128 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 129 {
 130         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 131 }
 132
 133 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 134 {
 135         struct object *object;
 136
 137         object = parse_object(sha1);
 138         if (!object)
 139                 die("bad object %s", name);
 140         object->flags |= flags;
 141         return object;
 142 }
 143
 144 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 145 {
 146         unsigned long flags = object->flags;
 147
 148         /*
 149          * Tag object? Look what it points to..
 150          */
 151         while (object->type == OBJ_TAG) {
 152                 struct tag *tag = (struct tag *) object;
 153                 if (revs->tag_objects && !(flags & UNINTERESTING))
 154                         add_pending_object(revs, object, tag->tag);
 155                 object = parse_object(tag->tagged->sha1);
 156                 if (!object)
 157                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 158         }
 159
 160         /*
 161          * Commit object? Just return it, we'll do all the complex
 162          * reachability crud.
 163          */
 164         if (object->type == OBJ_COMMIT) {
 165                 struct commit *commit = (struct commit *)object;
 166                 if (parse_commit(commit) < 0)
 167                         die("unable to parse commit %s", name);
 168                 if (flags & UNINTERESTING) {
 169                         commit->object.flags |= UNINTERESTING;
 170                         mark_parents_uninteresting(commit);
 171                         revs->limited = 1;
 172                 }
 173                 return commit;
 174         }
 175
 176         /*
 177          * Tree object? Either mark it uniniteresting, or add it
 178          * to the list of objects to look at later..
 179          */
 180         if (object->type == OBJ_TREE) {
 181                 struct tree *tree = (struct tree *)object;
 182                 if (!revs->tree_objects)
 183                         return NULL;
 184                 if (flags & UNINTERESTING) {
 185                         mark_tree_uninteresting(tree);
 186                         return NULL;
 187                 }
 188                 add_pending_object(revs, object, "");
 189                 return NULL;
 190         }
 191
 192         /*
 193          * Blob object? You know the drill by now..
 194          */
 195         if (object->type == OBJ_BLOB) {
 196                 struct blob *blob = (struct blob *)object;
 197                 if (!revs->blob_objects)
 198                         return NULL;
 199                 if (flags & UNINTERESTING) {
 200                         mark_blob_uninteresting(blob);
 201                         return NULL;
 202                 }
 203                 add_pending_object(revs, object, "");
 204                 return NULL;
 205         }
 206         die("%s is unknown object", name);
 207 }
 208
 209 static int everybody_uninteresting(struct commit_list *orig)
 210 {
 211         struct commit_list *list = orig;
 212         while (list) {
 213                 struct commit *commit = list->item;
 214                 list = list->next;
 215                 if (commit->object.flags & UNINTERESTING)
 216                         continue;
 217                 return 0;
 218         }
 219         return 1;
 220 }
 221
 222 /*
 223  * The goal is to get REV_TREE_NEW as the result only if the
 224  * diff consists of all '+' (and no other changes), and
 225  * REV_TREE_DIFFERENT otherwise (of course if the trees are
 226  * the same we want REV_TREE_SAME).  That means that once we
 227  * get to REV_TREE_DIFFERENT, we do not have to look any further.
 228  */
 229 static int tree_difference = REV_TREE_SAME;
 230
 231 static void file_add_remove(struct diff_options *options,
 232                     int addremove, unsigned mode,
 233                     const unsigned char *sha1,
 234                     const char *base, const char *path)
 235 {
 236         int diff = REV_TREE_DIFFERENT;
 237
 238         /*
 239          * Is it an add of a new file? It means that the old tree
 240          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 241          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 242          * (and if it already was "REV_TREE_NEW", we'll keep it
 243          * "REV_TREE_NEW" of course).
 244          */
 245         if (addremove == '+') {
 246                 diff = tree_difference;
 247                 if (diff != REV_TREE_SAME)
 248                         return;
 249                 diff = REV_TREE_NEW;
 250         }
 251         tree_difference = diff;
 252         if (tree_difference == REV_TREE_DIFFERENT)
 253                 options->has_changes = 1;
 254 }
 255
 256 static void file_change(struct diff_options *options,
 257                  unsigned old_mode, unsigned new_mode,
 258                  const unsigned char *old_sha1,
 259                  const unsigned char *new_sha1,
 260                  const char *base, const char *path)
 261 {
 262         tree_difference = REV_TREE_DIFFERENT;
 263         options->has_changes = 1;
 264 }
 265
 266 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 267 {
 268         if (!t1)
 269                 return REV_TREE_NEW;
 270         if (!t2)
 271                 return REV_TREE_DIFFERENT;
 272         tree_difference = REV_TREE_SAME;
 273         revs->pruning.has_changes = 0;
 274         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 275                            &revs->pruning) < 0)
 276                 return REV_TREE_DIFFERENT;
 277         return tree_difference;
 278 }
 279
 280 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 281 {
 282         int retval;
 283         void *tree;
 284         unsigned long size;
 285         struct tree_desc empty, real;
 286
 287         if (!t1)
 288                 return 0;
 289
 290         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 291         if (!tree)
 292                 return 0;
 293         init_tree_desc(&real, tree, size);
 294         init_tree_desc(&empty, "", 0);
 295
 296         tree_difference = REV_TREE_SAME;
 297         revs->pruning.has_changes = 0;
 298         retval = diff_tree(&empty, &real, "", &revs->pruning);
 299         free(tree);
 300
 301         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 302 }
 303
 304 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 305 {
 306         struct commit_list **pp, *parent;
 307         int tree_changed = 0, tree_same = 0;
 308
 309         if (!commit->tree)
 310                 return;
 311
 312         if (!commit->parents) {
 313                 if (!rev_same_tree_as_empty(revs, commit->tree))
 314                         commit->object.flags |= TREECHANGE;
 315                 return;
 316         }
 317
 318         pp = &commit->parents;
 319         while ((parent = *pp) != NULL) {
 320                 struct commit *p = parent->item;
 321
 322                 if (parse_commit(p) < 0)
 323                         die("cannot simplify commit %s (because of %s)",
 324                             sha1_to_hex(commit->object.sha1),
 325                             sha1_to_hex(p->object.sha1));
 326                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 327                 case REV_TREE_SAME:
 328                         tree_same = 1;
 329                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 330                                 /* Even if a merge with an uninteresting
 331                                  * side branch brought the entire change
 332                                  * we are interested in, we do not want
 333                                  * to lose the other branches of this
 334                                  * merge, so we just keep going.
 335                                  */
 336                                 pp = &parent->next;
 337                                 continue;
 338                         }
 339                         parent->next = NULL;
 340                         commit->parents = parent;
 341                         return;
 342
 343                 case REV_TREE_NEW:
 344                         if (revs->remove_empty_trees &&
 345                             rev_same_tree_as_empty(revs, p->tree)) {
 346                                 /* We are adding all the specified
 347                                  * paths from this parent, so the
 348                                  * history beyond this parent is not
 349                                  * interesting.  Remove its parents
 350                                  * (they are grandparents for us).
 351                                  * IOW, we pretend this parent is a
 352                                  * "root" commit.
 353                                  */
 354                                 if (parse_commit(p) < 0)
 355                                         die("cannot simplify commit %s (invalid %s)",
 356                                             sha1_to_hex(commit->object.sha1),
 357                                             sha1_to_hex(p->object.sha1));
 358                                 p->parents = NULL;
 359                         }
 360                 /* fallthrough */
 361                 case REV_TREE_DIFFERENT:
 362                         tree_changed = 1;
 363                         pp = &parent->next;
 364                         continue;
 365                 }
 366                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 367         }
 368         if (tree_changed && !tree_same)
 369                 commit->object.flags |= TREECHANGE;
 370 }
 371
 372 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 373 {
 374         struct commit_list *parent = commit->parents;
 375         unsigned left_flag;
 376         int add, rest;
 377
 378         if (commit->object.flags & ADDED)
 379                 return 0;
 380         commit->object.flags |= ADDED;
 381
 382         /*
 383          * If the commit is uninteresting, don't try to
 384          * prune parents - we want the maximal uninteresting
 385          * set.
 386          *
 387          * Normally we haven't parsed the parent
 388          * yet, so we won't have a parent of a parent
 389          * here. However, it may turn out that we've
 390          * reached this commit some other way (where it
 391          * wasn't uninteresting), in which case we need
 392          * to mark its parents recursively too..
 393          */
 394         if (commit->object.flags & UNINTERESTING) {
 395                 while (parent) {
 396                         struct commit *p = parent->item;
 397                         parent = parent->next;
 398                         if (parse_commit(p) < 0)
 399                                 return -1;
 400                         p->object.flags |= UNINTERESTING;
 401                         if (p->parents)
 402                                 mark_parents_uninteresting(p);
 403                         if (p->object.flags & SEEN)
 404                                 continue;
 405                         p->object.flags |= SEEN;
 406                         insert_by_date(p, list);
 407                 }
 408                 return 0;
 409         }
 410
 411         /*
 412          * Ok, the commit wasn't uninteresting. Try to
 413          * simplify the commit history and find the parent
 414          * that has no differences in the path set if one exists.
 415          */
 416         if (revs->prune_fn)
 417                 revs->prune_fn(revs, commit);
 418
 419         if (revs->no_walk)
 420                 return 0;
 421
 422         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 423
 424         rest = !revs->first_parent_only;
 425         for (parent = commit->parents, add = 1; parent; add = rest) {
 426                 struct commit *p = parent->item;
 427
 428                 parent = parent->next;
 429                 if (parse_commit(p) < 0)
 430                         return -1;
 431                 p->object.flags |= left_flag;
 432                 if (p->object.flags & SEEN)
 433                         continue;
 434                 p->object.flags |= SEEN;
 435                 if (add)
 436                         insert_by_date(p, list);
 437         }
 438         return 0;
 439 }
 440
 441 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 442 {
 443         struct commit_list *p;
 444         int left_count = 0, right_count = 0;
 445         int left_first;
 446         struct patch_ids ids;
 447
 448         /* First count the commits on the left and on the right */
 449         for (p = list; p; p = p->next) {
 450                 struct commit *commit = p->item;
 451                 unsigned flags = commit->object.flags;
 452                 if (flags & BOUNDARY)
 453                         ;
 454                 else if (flags & SYMMETRIC_LEFT)
 455                         left_count++;
 456                 else
 457                         right_count++;
 458         }
 459
 460         left_first = left_count < right_count;
 461         init_patch_ids(&ids);
 462         if (revs->diffopt.nr_paths) {
 463                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 464                 ids.diffopts.paths = revs->diffopt.paths;
 465                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 466         }
 467
 468         /* Compute patch-ids for one side */
 469         for (p = list; p; p = p->next) {
 470                 struct commit *commit = p->item;
 471                 unsigned flags = commit->object.flags;
 472
 473                 if (flags & BOUNDARY)
 474                         continue;
 475                 /*
 476                  * If we have fewer left, left_first is set and we omit
 477                  * commits on the right branch in this loop.  If we have
 478                  * fewer right, we skip the left ones.
 479                  */
 480                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 481                         continue;
 482                 commit->util = add_commit_patch_id(commit, &ids);
 483         }
 484
 485         /* Check the other side */
 486         for (p = list; p; p = p->next) {
 487                 struct commit *commit = p->item;
 488                 struct patch_id *id;
 489                 unsigned flags = commit->object.flags;
 490
 491                 if (flags & BOUNDARY)
 492                         continue;
 493                 /*
 494                  * If we have fewer left, left_first is set and we omit
 495                  * commits on the left branch in this loop.
 496                  */
 497                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 498                         continue;
 499
 500                 /*
 501                  * Have we seen the same patch id?
 502                  */
 503                 id = has_commit_patch_id(commit, &ids);
 504                 if (!id)
 505                         continue;
 506                 id->seen = 1;
 507                 commit->object.flags |= SHOWN;
 508         }
 509
 510         /* Now check the original side for seen ones */
 511         for (p = list; p; p = p->next) {
 512                 struct commit *commit = p->item;
 513                 struct patch_id *ent;
 514
 515                 ent = commit->util;
 516                 if (!ent)
 517                         continue;
 518                 if (ent->seen)
 519                         commit->object.flags |= SHOWN;
 520                 commit->util = NULL;
 521         }
 522
 523         free_patch_ids(&ids);
 524 }
 525
 526 static int limit_list(struct rev_info *revs)
 527 {
 528         struct commit_list *list = revs->commits;
 529         struct commit_list *newlist = NULL;
 530         struct commit_list **p = &newlist;
 531
 532         while (list) {
 533                 struct commit_list *entry = list;
 534                 struct commit *commit = list->item;
 535                 struct object *obj = &commit->object;
 536
 537                 list = list->next;
 538                 free(entry);
 539
 540                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 541                         obj->flags |= UNINTERESTING;
 542                 if (add_parents_to_list(revs, commit, &list) < 0)
 543                         return -1;
 544                 if (obj->flags & UNINTERESTING) {
 545                         mark_parents_uninteresting(commit);
 546                         if (everybody_uninteresting(list))
 547                                 break;
 548                         continue;
 549                 }
 550                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 551                         continue;
 552                 p = &commit_list_insert(commit, p)->next;
 553         }
 554         if (revs->cherry_pick)
 555                 cherry_pick_list(newlist, revs);
 556
 557         revs->commits = newlist;
 558         return 0;
 559 }
 560
 561 struct all_refs_cb {
 562         int all_flags;
 563         int warned_bad_reflog;
 564         struct rev_info *all_revs;
 565         const char *name_for_errormsg;
 566 };
 567
 568 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 569 {
 570         struct all_refs_cb *cb = cb_data;
 571         struct object *object = get_reference(cb->all_revs, path, sha1,
 572                                               cb->all_flags);
 573         add_pending_object(cb->all_revs, object, path);
 574         return 0;
 575 }
 576
 577 static void handle_all(struct rev_info *revs, unsigned flags)
 578 {
 579         struct all_refs_cb cb;
 580         cb.all_revs = revs;
 581         cb.all_flags = flags;
 582         for_each_ref(handle_one_ref, &cb);
 583 }
 584
 585 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 586 {
 587         struct all_refs_cb *cb = cb_data;
 588         if (!is_null_sha1(sha1)) {
 589                 struct object *o = parse_object(sha1);
 590                 if (o) {
 591                         o->flags |= cb->all_flags;
 592                         add_pending_object(cb->all_revs, o, "");
 593                 }
 594                 else if (!cb->warned_bad_reflog) {
 595                         warning("reflog of '%s' references pruned commits",
 596                                 cb->name_for_errormsg);
 597                         cb->warned_bad_reflog = 1;
 598                 }
 599         }
 600 }
 601
 602 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 603                 const char *email, unsigned long timestamp, int tz,
 604                 const char *message, void *cb_data)
 605 {
 606         handle_one_reflog_commit(osha1, cb_data);
 607         handle_one_reflog_commit(nsha1, cb_data);
 608         return 0;
 609 }
 610
 611 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 612 {
 613         struct all_refs_cb *cb = cb_data;
 614         cb->warned_bad_reflog = 0;
 615         cb->name_for_errormsg = path;
 616         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 617         return 0;
 618 }
 619
 620 static void handle_reflog(struct rev_info *revs, unsigned flags)
 621 {
 622         struct all_refs_cb cb;
 623         cb.all_revs = revs;
 624         cb.all_flags = flags;
 625         for_each_reflog(handle_one_reflog, &cb);
 626 }
 627
 628 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 629 {
 630         unsigned char sha1[20];
 631         struct object *it;
 632         struct commit *commit;
 633         struct commit_list *parents;
 634
 635         if (*arg == '^') {
 636                 flags ^= UNINTERESTING;
 637                 arg++;
 638         }
 639         if (get_sha1(arg, sha1))
 640                 return 0;
 641         while (1) {
 642                 it = get_reference(revs, arg, sha1, 0);
 643                 if (it->type != OBJ_TAG)
 644                         break;
 645                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 646         }
 647         if (it->type != OBJ_COMMIT)
 648                 return 0;
 649         commit = (struct commit *)it;
 650         for (parents = commit->parents; parents; parents = parents->next) {
 651                 it = &parents->item->object;
 652                 it->flags |= flags;
 653                 add_pending_object(revs, it, arg);
 654         }
 655         return 1;
 656 }
 657
 658 void init_revisions(struct rev_info *revs, const char *prefix)
 659 {
 660         memset(revs, 0, sizeof(*revs));
 661
 662         revs->abbrev = DEFAULT_ABBREV;
 663         revs->ignore_merges = 1;
 664         revs->simplify_history = 1;
 665         revs->pruning.recursive = 1;
 666         revs->pruning.quiet = 1;
 667         revs->pruning.add_remove = file_add_remove;
 668         revs->pruning.change = file_change;
 669         revs->lifo = 1;
 670         revs->dense = 1;
 671         revs->prefix = prefix;
 672         revs->max_age = -1;
 673         revs->min_age = -1;
 674         revs->skip_count = -1;
 675         revs->max_count = -1;
 676
 677         revs->prune_fn = NULL;
 678         revs->prune_data = NULL;
 679
 680         revs->topo_setter = topo_sort_default_setter;
 681         revs->topo_getter = topo_sort_default_getter;
 682
 683         revs->commit_format = CMIT_FMT_DEFAULT;
 684
 685         diff_setup(&revs->diffopt);
 686 }
 687
 688 static void add_pending_commit_list(struct rev_info *revs,
 689                                     struct commit_list *commit_list,
 690                                     unsigned int flags)
 691 {
 692         while (commit_list) {
 693                 struct object *object = &commit_list->item->object;
 694                 object->flags |= flags;
 695                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 696                 commit_list = commit_list->next;
 697         }
 698 }
 699
 700 static void prepare_show_merge(struct rev_info *revs)
 701 {
 702         struct commit_list *bases;
 703         struct commit *head, *other;
 704         unsigned char sha1[20];
 705         const char **prune = NULL;
 706         int i, prune_num = 1; /* counting terminating NULL */
 707
 708         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 709                 die("--merge without HEAD?");
 710         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 711                 die("--merge without MERGE_HEAD?");
 712         add_pending_object(revs, &head->object, "HEAD");
 713         add_pending_object(revs, &other->object, "MERGE_HEAD");
 714         bases = get_merge_bases(head, other, 1);
 715         while (bases) {
 716                 struct commit *it = bases->item;
 717                 struct commit_list *n = bases->next;
 718                 free(bases);
 719                 bases = n;
 720                 it->object.flags |= UNINTERESTING;
 721                 add_pending_object(revs, &it->object, "(merge-base)");
 722         }
 723
 724         if (!active_nr)
 725                 read_cache();
 726         for (i = 0; i < active_nr; i++) {
 727                 struct cache_entry *ce = active_cache[i];
 728                 if (!ce_stage(ce))
 729                         continue;
 730                 if (ce_path_match(ce, revs->prune_data)) {
 731                         prune_num++;
 732                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 733                         prune[prune_num-2] = ce->name;
 734                         prune[prune_num-1] = NULL;
 735                 }
 736                 while ((i+1 < active_nr) &&
 737                        ce_same_name(ce, active_cache[i+1]))
 738                         i++;
 739         }
 740         revs->prune_data = prune;
 741 }
 742
 743 int handle_revision_arg(const char *arg, struct rev_info *revs,
 744                         int flags,
 745                         int cant_be_filename)
 746 {
 747         unsigned mode;
 748         char *dotdot;
 749         struct object *object;
 750         unsigned char sha1[20];
 751         int local_flags;
 752
 753         dotdot = strstr(arg, "..");
 754         if (dotdot) {
 755                 unsigned char from_sha1[20];
 756                 const char *next = dotdot + 2;
 757                 const char *this = arg;
 758                 int symmetric = *next == '.';
 759                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 760
 761                 *dotdot = 0;
 762                 next += symmetric;
 763
 764                 if (!*next)
 765                         next = "HEAD";
 766                 if (dotdot == arg)
 767                         this = "HEAD";
 768                 if (!get_sha1(this, from_sha1) &&
 769                     !get_sha1(next, sha1)) {
 770                         struct commit *a, *b;
 771                         struct commit_list *exclude;
 772
 773                         a = lookup_commit_reference(from_sha1);
 774                         b = lookup_commit_reference(sha1);
 775                         if (!a || !b) {
 776                                 die(symmetric ?
 777                                     "Invalid symmetric difference expression %s...%s" :
 778                                     "Invalid revision range %s..%s",
 779                                     arg, next);
 780                         }
 781
 782                         if (!cant_be_filename) {
 783                                 *dotdot = '.';
 784                                 verify_non_filename(revs->prefix, arg);
 785                         }
 786
 787                         if (symmetric) {
 788                                 exclude = get_merge_bases(a, b, 1);
 789                                 add_pending_commit_list(revs, exclude,
 790                                                         flags_exclude);
 791                                 free_commit_list(exclude);
 792                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 793                         } else
 794                                 a->object.flags |= flags_exclude;
 795                         b->object.flags |= flags;
 796                         add_pending_object(revs, &a->object, this);
 797                         add_pending_object(revs, &b->object, next);
 798                         return 0;
 799                 }
 800                 *dotdot = '.';
 801         }
 802         dotdot = strstr(arg, "^@");
 803         if (dotdot && !dotdot[2]) {
 804                 *dotdot = 0;
 805                 if (add_parents_only(revs, arg, flags))
 806                         return 0;
 807                 *dotdot = '^';
 808         }
 809         dotdot = strstr(arg, "^!");
 810         if (dotdot && !dotdot[2]) {
 811                 *dotdot = 0;
 812                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 813                         *dotdot = '^';
 814         }
 815
 816         local_flags = 0;
 817         if (*arg == '^') {
 818                 local_flags = UNINTERESTING;
 819                 arg++;
 820         }
 821         if (get_sha1_with_mode(arg, sha1, &mode))
 822                 return -1;
 823         if (!cant_be_filename)
 824                 verify_non_filename(revs->prefix, arg);
 825         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 826         add_pending_object_with_mode(revs, object, arg, mode);
 827         return 0;
 828 }
 829
 830 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 831 {
 832         if (!revs->grep_filter) {
 833                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 834                 opt->status_only = 1;
 835                 opt->pattern_tail = &(opt->pattern_list);
 836                 opt->regflags = REG_NEWLINE;
 837                 revs->grep_filter = opt;
 838         }
 839         append_grep_pattern(revs->grep_filter, ptn,
 840                             "command line", 0, what);
 841 }
 842
 843 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 844 {
 845         char *pat;
 846         const char *prefix;
 847         int patlen, fldlen;
 848
 849         fldlen = strlen(field);
 850         patlen = strlen(pattern);
 851         pat = xmalloc(patlen + fldlen + 10);
 852         prefix = ".*";
 853         if (*pattern == '^') {
 854                 prefix = "";
 855                 pattern++;
 856         }
 857         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 858         add_grep(revs, pat, GREP_PATTERN_HEAD);
 859 }
 860
 861 static void add_message_grep(struct rev_info *revs, const char *pattern)
 862 {
 863         add_grep(revs, pattern, GREP_PATTERN_BODY);
 864 }
 865
 866 static void add_ignore_packed(struct rev_info *revs, const char *name)
 867 {
 868         int num = ++revs->num_ignore_packed;
 869
 870         revs->ignore_packed = xrealloc(revs->ignore_packed,
 871                                        sizeof(const char **) * (num + 1));
 872         revs->ignore_packed[num-1] = name;
 873         revs->ignore_packed[num] = NULL;
 874 }
 875
 876 /*
 877  * Parse revision information, filling in the "rev_info" structure,
 878  * and removing the used arguments from the argument list.
 879  *
 880  * Returns the number of arguments left that weren't recognized
 881  * (which are also moved to the head of the argument list)
 882  */
 883 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 884 {
 885         int i, flags, seen_dashdash, show_merge;
 886         const char **unrecognized = argv + 1;
 887         int left = 1;
 888         int all_match = 0;
 889         int regflags = 0;
 890
 891         /* First, search for "--" */
 892         seen_dashdash = 0;
 893         for (i = 1; i < argc; i++) {
 894                 const char *arg = argv[i];
 895                 if (strcmp(arg, "--"))
 896                         continue;
 897                 argv[i] = NULL;
 898                 argc = i;
 899                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 900                 seen_dashdash = 1;
 901                 break;
 902         }
 903
 904         flags = show_merge = 0;
 905         for (i = 1; i < argc; i++) {
 906                 const char *arg = argv[i];
 907                 if (*arg == '-') {
 908                         int opts;
 909                         if (!prefixcmp(arg, "--max-count=")) {
 910                                 revs->max_count = atoi(arg + 12);
 911                                 continue;
 912                         }
 913                         if (!prefixcmp(arg, "--skip=")) {
 914                                 revs->skip_count = atoi(arg + 7);
 915                                 continue;
 916                         }
 917                         /* accept -<digit>, like traditional "head" */
 918                         if ((*arg == '-') && isdigit(arg[1])) {
 919                                 revs->max_count = atoi(arg + 1);
 920                                 continue;
 921                         }
 922                         if (!strcmp(arg, "-n")) {
 923                                 if (argc <= i + 1)
 924                                         die("-n requires an argument");
 925                                 revs->max_count = atoi(argv[++i]);
 926                                 continue;
 927                         }
 928                         if (!prefixcmp(arg, "-n")) {
 929                                 revs->max_count = atoi(arg + 2);
 930                                 continue;
 931                         }
 932                         if (!prefixcmp(arg, "--max-age=")) {
 933                                 revs->max_age = atoi(arg + 10);
 934                                 continue;
 935                         }
 936                         if (!prefixcmp(arg, "--since=")) {
 937                                 revs->max_age = approxidate(arg + 8);
 938                                 continue;
 939                         }
 940                         if (!prefixcmp(arg, "--after=")) {
 941                                 revs->max_age = approxidate(arg + 8);
 942                                 continue;
 943                         }
 944                         if (!prefixcmp(arg, "--min-age=")) {
 945                                 revs->min_age = atoi(arg + 10);
 946                                 continue;
 947                         }
 948                         if (!prefixcmp(arg, "--before=")) {
 949                                 revs->min_age = approxidate(arg + 9);
 950                                 continue;
 951                         }
 952                         if (!prefixcmp(arg, "--until=")) {
 953                                 revs->min_age = approxidate(arg + 8);
 954                                 continue;
 955                         }
 956                         if (!strcmp(arg, "--all")) {
 957                                 handle_all(revs, flags);
 958                                 continue;
 959                         }
 960                         if (!strcmp(arg, "--first-parent")) {
 961                                 revs->first_parent_only = 1;
 962                                 continue;
 963                         }
 964                         if (!strcmp(arg, "--reflog")) {
 965                                 handle_reflog(revs, flags);
 966                                 continue;
 967                         }
 968                         if (!strcmp(arg, "-g") ||
 969                                         !strcmp(arg, "--walk-reflogs")) {
 970                                 init_reflog_walk(&revs->reflog_info);
 971                                 continue;
 972                         }
 973                         if (!strcmp(arg, "--not")) {
 974                                 flags ^= UNINTERESTING;
 975                                 continue;
 976                         }
 977                         if (!strcmp(arg, "--default")) {
 978                                 if (++i >= argc)
 979                                         die("bad --default argument");
 980                                 def = argv[i];
 981                                 continue;
 982                         }
 983                         if (!strcmp(arg, "--merge")) {
 984                                 show_merge = 1;
 985                                 continue;
 986                         }
 987                         if (!strcmp(arg, "--topo-order")) {
 988                                 revs->topo_order = 1;
 989                                 continue;
 990                         }
 991                         if (!strcmp(arg, "--date-order")) {
 992                                 revs->lifo = 0;
 993                                 revs->topo_order = 1;
 994                                 continue;
 995                         }
 996                         if (!strcmp(arg, "--parents")) {
 997                                 revs->parents = 1;
 998                                 continue;
 999                         }
1000                         if (!strcmp(arg, "--dense")) {
1001                                 revs->dense = 1;
1002                                 continue;
1003                         }
1004                         if (!strcmp(arg, "--sparse")) {
1005                                 revs->dense = 0;
1006                                 continue;
1007                         }
1008                         if (!strcmp(arg, "--remove-empty")) {
1009                                 revs->remove_empty_trees = 1;
1010                                 continue;
1011                         }
1012                         if (!strcmp(arg, "--no-merges")) {
1013                                 revs->no_merges = 1;
1014                                 continue;
1015                         }
1016                         if (!strcmp(arg, "--boundary")) {
1017                                 revs->boundary = 1;
1018                                 continue;
1019                         }
1020                         if (!strcmp(arg, "--left-right")) {
1021                                 revs->left_right = 1;
1022                                 continue;
1023                         }
1024                         if (!strcmp(arg, "--cherry-pick")) {
1025                                 revs->cherry_pick = 1;
1026                                 continue;
1027                         }
1028                         if (!strcmp(arg, "--objects")) {
1029                                 revs->tag_objects = 1;
1030                                 revs->tree_objects = 1;
1031                                 revs->blob_objects = 1;
1032                                 continue;
1033                         }
1034                         if (!strcmp(arg, "--objects-edge")) {
1035                                 revs->tag_objects = 1;
1036                                 revs->tree_objects = 1;
1037                                 revs->blob_objects = 1;
1038                                 revs->edge_hint = 1;
1039                                 continue;
1040                         }
1041                         if (!strcmp(arg, "--unpacked")) {
1042                                 revs->unpacked = 1;
1043                                 free(revs->ignore_packed);
1044                                 revs->ignore_packed = NULL;
1045                                 revs->num_ignore_packed = 0;
1046                                 continue;
1047                         }
1048                         if (!prefixcmp(arg, "--unpacked=")) {
1049                                 revs->unpacked = 1;
1050                                 add_ignore_packed(revs, arg+11);
1051                                 continue;
1052                         }
1053                         if (!strcmp(arg, "-r")) {
1054                                 revs->diff = 1;
1055                                 revs->diffopt.recursive = 1;
1056                                 continue;
1057                         }
1058                         if (!strcmp(arg, "-t")) {
1059                                 revs->diff = 1;
1060                                 revs->diffopt.recursive = 1;
1061                                 revs->diffopt.tree_in_recursive = 1;
1062                                 continue;
1063                         }
1064                         if (!strcmp(arg, "-m")) {
1065                                 revs->ignore_merges = 0;
1066                                 continue;
1067                         }
1068                         if (!strcmp(arg, "-c")) {
1069                                 revs->diff = 1;
1070                                 revs->dense_combined_merges = 0;
1071                                 revs->combine_merges = 1;
1072                                 continue;
1073                         }
1074                         if (!strcmp(arg, "--cc")) {
1075                                 revs->diff = 1;
1076                                 revs->dense_combined_merges = 1;
1077                                 revs->combine_merges = 1;
1078                                 continue;
1079                         }
1080                         if (!strcmp(arg, "-v")) {
1081                                 revs->verbose_header = 1;
1082                                 continue;
1083                         }
1084                         if (!prefixcmp(arg, "--pretty")) {
1085                                 revs->verbose_header = 1;
1086                                 revs->commit_format = get_commit_format(arg+8);
1087                                 continue;
1088                         }
1089                         if (!strcmp(arg, "--root")) {
1090                                 revs->show_root_diff = 1;
1091                                 continue;
1092                         }
1093                         if (!strcmp(arg, "--no-commit-id")) {
1094                                 revs->no_commit_id = 1;
1095                                 continue;
1096                         }
1097                         if (!strcmp(arg, "--always")) {
1098                                 revs->always_show_header = 1;
1099                                 continue;
1100                         }
1101                         if (!strcmp(arg, "--no-abbrev")) {
1102                                 revs->abbrev = 0;
1103                                 continue;
1104                         }
1105                         if (!strcmp(arg, "--abbrev")) {
1106                                 revs->abbrev = DEFAULT_ABBREV;
1107                                 continue;
1108                         }
1109                         if (!prefixcmp(arg, "--abbrev=")) {
1110                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1111                                 if (revs->abbrev < MINIMUM_ABBREV)
1112                                         revs->abbrev = MINIMUM_ABBREV;
1113                                 else if (revs->abbrev > 40)
1114                                         revs->abbrev = 40;
1115                                 continue;
1116                         }
1117                         if (!strcmp(arg, "--abbrev-commit")) {
1118                                 revs->abbrev_commit = 1;
1119                                 continue;
1120                         }
1121                         if (!strcmp(arg, "--full-diff")) {
1122                                 revs->diff = 1;
1123                                 revs->full_diff = 1;
1124                                 continue;
1125                         }
1126                         if (!strcmp(arg, "--full-history")) {
1127                                 revs->simplify_history = 0;
1128                                 continue;
1129                         }
1130                         if (!strcmp(arg, "--relative-date")) {
1131                                 revs->date_mode = DATE_RELATIVE;
1132                                 continue;
1133                         }
1134                         if (!strncmp(arg, "--date=", 7)) {
1135                                 if (!strcmp(arg + 7, "relative"))
1136                                         revs->date_mode = DATE_RELATIVE;
1137                                 else if (!strcmp(arg + 7, "iso8601") ||
1138                                          !strcmp(arg + 7, "iso"))
1139                                         revs->date_mode = DATE_ISO8601;
1140                                 else if (!strcmp(arg + 7, "rfc2822") ||
1141                                          !strcmp(arg + 7, "rfc"))
1142                                         revs->date_mode = DATE_RFC2822;
1143                                 else if (!strcmp(arg + 7, "short"))
1144                                         revs->date_mode = DATE_SHORT;
1145                                 else if (!strcmp(arg + 7, "local"))
1146                                         revs->date_mode = DATE_LOCAL;
1147                                 else if (!strcmp(arg + 7, "default"))
1148                                         revs->date_mode = DATE_NORMAL;
1149                                 else
1150                                         die("unknown date format %s", arg);
1151                                 continue;
1152                         }
1153
1154                         /*
1155                          * Grepping the commit log
1156                          */
1157                         if (!prefixcmp(arg, "--author=")) {
1158                                 add_header_grep(revs, "author", arg+9);
1159                                 continue;
1160                         }
1161                         if (!prefixcmp(arg, "--committer=")) {
1162                                 add_header_grep(revs, "committer", arg+12);
1163                                 continue;
1164                         }
1165                         if (!prefixcmp(arg, "--grep=")) {
1166                                 add_message_grep(revs, arg+7);
1167                                 continue;
1168                         }
1169                         if (!strcmp(arg, "--extended-regexp") ||
1170                             !strcmp(arg, "-E")) {
1171                                 regflags |= REG_EXTENDED;
1172                                 continue;
1173                         }
1174                         if (!strcmp(arg, "--regexp-ignore-case") ||
1175                             !strcmp(arg, "-i")) {
1176                                 regflags |= REG_ICASE;
1177                                 continue;
1178                         }
1179                         if (!strcmp(arg, "--all-match")) {
1180                                 all_match = 1;
1181                                 continue;
1182                         }
1183                         if (!prefixcmp(arg, "--encoding=")) {
1184                                 arg += 11;
1185                                 if (strcmp(arg, "none"))
1186                                         git_log_output_encoding = xstrdup(arg);
1187                                 else
1188                                         git_log_output_encoding = "";
1189                                 continue;
1190                         }
1191                         if (!strcmp(arg, "--reverse")) {
1192                                 revs->reverse ^= 1;
1193                                 continue;
1194                         }
1195                         if (!strcmp(arg, "--no-walk")) {
1196                                 revs->no_walk = 1;
1197                                 continue;
1198                         }
1199                         if (!strcmp(arg, "--do-walk")) {
1200                                 revs->no_walk = 0;
1201                                 continue;
1202                         }
1203
1204                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1205                         if (opts > 0) {
1206                                 if (strcmp(argv[i], "-z"))
1207                                         revs->diff = 1;
1208                                 i += opts - 1;
1209                                 continue;
1210                         }
1211                         *unrecognized++ = arg;
1212                         left++;
1213                         continue;
1214                 }
1215
1216                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1217                         int j;
1218                         if (seen_dashdash || *arg == '^')
1219                                 die("bad revision '%s'", arg);
1220
1221                         /* If we didn't have a "--":
1222                          * (1) all filenames must exist;
1223                          * (2) all rev-args must not be interpretable
1224                          *     as a valid filename.
1225                          * but the latter we have checked in the main loop.
1226                          */
1227                         for (j = i; j < argc; j++)
1228                                 verify_filename(revs->prefix, argv[j]);
1229
1230                         revs->prune_data = get_pathspec(revs->prefix,
1231                                                         argv + i);
1232                         break;
1233                 }
1234         }
1235
1236         if (revs->grep_filter)
1237                 revs->grep_filter->regflags |= regflags;
1238
1239         if (show_merge)
1240                 prepare_show_merge(revs);
1241         if (def && !revs->pending.nr) {
1242                 unsigned char sha1[20];
1243                 struct object *object;
1244                 unsigned mode;
1245                 if (get_sha1_with_mode(def, sha1, &mode))
1246                         die("bad default revision '%s'", def);
1247                 object = get_reference(revs, def, sha1, 0);
1248                 add_pending_object_with_mode(revs, object, def, mode);
1249         }
1250
1251         if (revs->topo_order)
1252                 revs->limited = 1;
1253
1254         if (revs->prune_data) {
1255                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1256                 /* Can't prune commits with rename following: the paths change.. */
1257                 if (!revs->diffopt.follow_renames)
1258                         revs->prune_fn = try_to_simplify_commit;
1259                 if (!revs->full_diff)
1260                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1261         }
1262         if (revs->combine_merges) {
1263                 revs->ignore_merges = 0;
1264                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1265                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1266         }
1267         revs->diffopt.abbrev = revs->abbrev;
1268         if (diff_setup_done(&revs->diffopt) < 0)
1269                 die("diff_setup_done failed");
1270
1271         if (revs->grep_filter) {
1272                 revs->grep_filter->all_match = all_match;
1273                 compile_grep_patterns(revs->grep_filter);
1274         }
1275
1276         return left;
1277 }
1278
1279 int prepare_revision_walk(struct rev_info *revs)
1280 {
1281         int nr = revs->pending.nr;
1282         struct object_array_entry *e, *list;
1283
1284         e = list = revs->pending.objects;
1285         revs->pending.nr = 0;
1286         revs->pending.alloc = 0;
1287         revs->pending.objects = NULL;
1288         while (--nr >= 0) {
1289                 struct commit *commit = handle_commit(revs, e->item, e->name);
1290                 if (commit) {
1291                         if (!(commit->object.flags & SEEN)) {
1292                                 commit->object.flags |= SEEN;
1293                                 insert_by_date(commit, &revs->commits);
1294                         }
1295                 }
1296                 e++;
1297         }
1298         free(list);
1299
1300         if (revs->no_walk)
1301                 return 0;
1302         if (revs->limited)
1303                 if (limit_list(revs) < 0)
1304                         return -1;
1305         if (revs->topo_order)
1306                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
1307                                              revs->topo_setter,
1308                                              revs->topo_getter);
1309         return 0;
1310 }
1311
1312 enum rewrite_result {
1313         rewrite_one_ok,
1314         rewrite_one_noparents,
1315         rewrite_one_error,
1316 };
1317
1318 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1319 {
1320         for (;;) {
1321                 struct commit *p = *pp;
1322                 if (!revs->limited)
1323                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1324                                 return rewrite_one_error;
1325                 if (p->parents && p->parents->next)
1326                         return rewrite_one_ok;
1327                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
1328                         return rewrite_one_ok;
1329                 if (!p->parents)
1330                         return rewrite_one_noparents;
1331                 *pp = p->parents->item;
1332         }
1333 }
1334
1335 static void remove_duplicate_parents(struct commit *commit)
1336 {
1337         struct commit_list **pp, *p;
1338
1339         /* Examine existing parents while marking ones we have seen... */
1340         pp = &commit->parents;
1341         while ((p = *pp) != NULL) {
1342                 struct commit *parent = p->item;
1343                 if (parent->object.flags & TMP_MARK) {
1344                         *pp = p->next;
1345                         continue;
1346                 }
1347                 parent->object.flags |= TMP_MARK;
1348                 pp = &p->next;
1349         }
1350         /* ... and clear the temporary mark */
1351         for (p = commit->parents; p; p = p->next)
1352                 p->item->object.flags &= ~TMP_MARK;
1353 }
1354
1355 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1356 {
1357         struct commit_list **pp = &commit->parents;
1358         while (*pp) {
1359                 struct commit_list *parent = *pp;
1360                 switch (rewrite_one(revs, &parent->item)) {
1361                 case rewrite_one_ok:
1362                         break;
1363                 case rewrite_one_noparents:
1364                         *pp = parent->next;
1365                         continue;
1366                 case rewrite_one_error:
1367                         return -1;
1368                 }
1369                 pp = &parent->next;
1370         }
1371         remove_duplicate_parents(commit);
1372         return 0;
1373 }
1374
1375 static int commit_match(struct commit *commit, struct rev_info *opt)
1376 {
1377         if (!opt->grep_filter)
1378                 return 1;
1379         return grep_buffer(opt->grep_filter,
1380                            NULL, /* we say nothing, not even filename */
1381                            commit->buffer, strlen(commit->buffer));
1382 }
1383
1384 static struct commit *get_revision_1(struct rev_info *revs)
1385 {
1386         if (!revs->commits)
1387                 return NULL;
1388
1389         do {
1390                 struct commit_list *entry = revs->commits;
1391                 struct commit *commit = entry->item;
1392
1393                 revs->commits = entry->next;
1394                 free(entry);
1395
1396                 if (revs->reflog_info)
1397                         fake_reflog_parent(revs->reflog_info, commit);
1398
1399                 /*
1400                  * If we haven't done the list limiting, we need to look at
1401                  * the parents here. We also need to do the date-based limiting
1402                  * that we'd otherwise have done in limit_list().
1403                  */
1404                 if (!revs->limited) {
1405                         if (revs->max_age != -1 &&
1406                             (commit->date < revs->max_age))
1407                                 continue;
1408                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1409                                 return NULL;
1410                 }
1411                 if (commit->object.flags & SHOWN)
1412                         continue;
1413
1414                 if (revs->unpacked && has_sha1_pack(commit->object.sha1,
1415                                                     revs->ignore_packed))
1416                     continue;
1417
1418                 if (commit->object.flags & UNINTERESTING)
1419                         continue;
1420                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1421                         continue;
1422                 if (revs->no_merges &&
1423                     commit->parents && commit->parents->next)
1424                         continue;
1425                 if (!commit_match(commit, revs))
1426                         continue;
1427                 if (revs->prune_fn && revs->dense) {
1428                         /* Commit without changes? */
1429                         if (!(commit->object.flags & TREECHANGE)) {
1430                                 /* drop merges unless we want parenthood */
1431                                 if (!revs->parents)
1432                                         continue;
1433                                 /* non-merge - always ignore it */
1434                                 if (!commit->parents || !commit->parents->next)
1435                                         continue;
1436                         }
1437                         if (revs->parents && rewrite_parents(revs, commit) < 0)
1438                                 return NULL;
1439                 }
1440                 return commit;
1441         } while (revs->commits);
1442         return NULL;
1443 }
1444
1445 static void gc_boundary(struct object_array *array)
1446 {
1447         unsigned nr = array->nr;
1448         unsigned alloc = array->alloc;
1449         struct object_array_entry *objects = array->objects;
1450
1451         if (alloc <= nr) {
1452                 unsigned i, j;
1453                 for (i = j = 0; i < nr; i++) {
1454                         if (objects[i].item->flags & SHOWN)
1455                                 continue;
1456                         if (i != j)
1457                                 objects[j] = objects[i];
1458                         j++;
1459                 }
1460                 for (i = j; i < nr; i++)
1461                         objects[i].item = NULL;
1462                 array->nr = j;
1463         }
1464 }
1465
1466 struct commit *get_revision(struct rev_info *revs)
1467 {
1468         struct commit *c = NULL;
1469         struct commit_list *l;
1470
1471         if (revs->boundary == 2) {
1472                 unsigned i;
1473                 struct object_array *array = &revs->boundary_commits;
1474                 struct object_array_entry *objects = array->objects;
1475                 for (i = 0; i < array->nr; i++) {
1476                         c = (struct commit *)(objects[i].item);
1477                         if (!c)
1478                                 continue;
1479                         if (!(c->object.flags & CHILD_SHOWN))
1480                                 continue;
1481                         if (!(c->object.flags & SHOWN))
1482                                 break;
1483                 }
1484                 if (array->nr <= i)
1485                         return NULL;
1486
1487                 c->object.flags |= SHOWN | BOUNDARY;
1488                 return c;
1489         }
1490
1491         if (revs->reverse) {
1492                 int limit = -1;
1493
1494                 if (0 <= revs->max_count) {
1495                         limit = revs->max_count;
1496                         if (0 < revs->skip_count)
1497                                 limit += revs->skip_count;
1498                 }
1499                 l = NULL;
1500                 while ((c = get_revision_1(revs))) {
1501                         commit_list_insert(c, &l);
1502                         if ((0 < limit) && !--limit)
1503                                 break;
1504                 }
1505                 revs->commits = l;
1506                 revs->reverse = 0;
1507                 revs->max_count = -1;
1508                 c = NULL;
1509         }
1510
1511         /*
1512          * Now pick up what they want to give us
1513          */
1514         c = get_revision_1(revs);
1515         if (c) {
1516                 while (0 < revs->skip_count) {
1517                         revs->skip_count--;
1518                         c = get_revision_1(revs);
1519                         if (!c)
1520                                 break;
1521                 }
1522         }
1523
1524         /*
1525          * Check the max_count.
1526          */
1527         switch (revs->max_count) {
1528         case -1:
1529                 break;
1530         case 0:
1531                 c = NULL;
1532                 break;
1533         default:
1534                 revs->max_count--;
1535         }
1536
1537         if (c)
1538                 c->object.flags |= SHOWN;
1539
1540         if (!revs->boundary) {
1541                 return c;
1542         }
1543
1544         if (!c) {
1545                 /*
1546                  * get_revision_1() runs out the commits, and
1547                  * we are done computing the boundaries.
1548                  * switch to boundary commits output mode.
1549                  */
1550                 revs->boundary = 2;
1551                 return get_revision(revs);
1552         }
1553
1554         /*
1555          * boundary commits are the commits that are parents of the
1556          * ones we got from get_revision_1() but they themselves are
1557          * not returned from get_revision_1().  Before returning
1558          * 'c', we need to mark its parents that they could be boundaries.
1559          */
1560
1561         for (l = c->parents; l; l = l->next) {
1562                 struct object *p;
1563                 p = &(l->item->object);
1564                 if (p->flags & (CHILD_SHOWN | SHOWN))
1565                         continue;
1566                 p->flags |= CHILD_SHOWN;
1567                 gc_boundary(&revs->boundary_commits);
1568                 add_object_array(p, NULL, &revs->boundary_commits);
1569         }
1570
1571         return c;
1572 }