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 volatile show_early_output_fn_t show_early_output;
  14
  15 static char *path_name(struct name_path *path, const char *name)
  16 {
  17         struct name_path *p;
  18         char *n, *m;
  19         int nlen = strlen(name);
  20         int len = nlen + 1;
  21
  22         for (p = path; p; p = p->up) {
  23                 if (p->elem_len)
  24                         len += p->elem_len + 1;
  25         }
  26         n = xmalloc(len);
  27         m = n + len - (nlen + 1);
  28         strcpy(m, name);
  29         for (p = path; p; p = p->up) {
  30                 if (p->elem_len) {
  31                         m -= p->elem_len + 1;
  32                         memcpy(m, p->elem, p->elem_len);
  33                         m[p->elem_len] = '/';
  34                 }
  35         }
  36         return n;
  37 }
  38
  39 void add_object(struct object *obj,
  40                 struct object_array *p,
  41                 struct name_path *path,
  42                 const char *name)
  43 {
  44         add_object_array(obj, path_name(path, name), p);
  45 }
  46
  47 static void mark_blob_uninteresting(struct blob *blob)
  48 {
  49         if (!blob)
  50                 return;
  51         if (blob->object.flags & UNINTERESTING)
  52                 return;
  53         blob->object.flags |= UNINTERESTING;
  54 }
  55
  56 void mark_tree_uninteresting(struct tree *tree)
  57 {
  58         struct tree_desc desc;
  59         struct name_entry entry;
  60         struct object *obj = &tree->object;
  61
  62         if (!tree)
  63                 return;
  64         if (obj->flags & UNINTERESTING)
  65                 return;
  66         obj->flags |= UNINTERESTING;
  67         if (!has_sha1_file(obj->sha1))
  68                 return;
  69         if (parse_tree(tree) < 0)
  70                 die("bad tree %s", sha1_to_hex(obj->sha1));
  71
  72         init_tree_desc(&desc, tree->buffer, tree->size);
  73         while (tree_entry(&desc, &entry)) {
  74                 switch (object_type(entry.mode)) {
  75                 case OBJ_TREE:
  76                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  77                         break;
  78                 case OBJ_BLOB:
  79                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  80                         break;
  81                 default:
  82                         /* Subproject commit - not in this repository */
  83                         break;
  84                 }
  85         }
  86
  87         /*
  88          * We don't care about the tree any more
  89          * after it has been marked uninteresting.
  90          */
  91         free(tree->buffer);
  92         tree->buffer = NULL;
  93 }
  94
  95 void mark_parents_uninteresting(struct commit *commit)
  96 {
  97         struct commit_list *parents = commit->parents;
  98
  99         while (parents) {
 100                 struct commit *commit = parents->item;
 101                 if (!(commit->object.flags & UNINTERESTING)) {
 102                         commit->object.flags |= UNINTERESTING;
 103
 104                         /*
 105                          * Normally we haven't parsed the parent
 106                          * yet, so we won't have a parent of a parent
 107                          * here. However, it may turn out that we've
 108                          * reached this commit some other way (where it
 109                          * wasn't uninteresting), in which case we need
 110                          * to mark its parents recursively too..
 111                          */
 112                         if (commit->parents)
 113                                 mark_parents_uninteresting(commit);
 114                 }
 115
 116                 /*
 117                  * A missing commit is ok iff its parent is marked
 118                  * uninteresting.
 119                  *
 120                  * We just mark such a thing parsed, so that when
 121                  * it is popped next time around, we won't be trying
 122                  * to parse it and get an error.
 123                  */
 124                 if (!has_sha1_file(commit->object.sha1))
 125                         commit->object.parsed = 1;
 126                 parents = parents->next;
 127         }
 128 }
 129
 130 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 131 {
 132         if (revs->no_walk && (obj->flags & UNINTERESTING))
 133                 die("object ranges do not make sense when not walking revisions");
 134         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 135                         add_reflog_for_walk(revs->reflog_info,
 136                                 (struct commit *)obj, name))
 137                 return;
 138         add_object_array_with_mode(obj, name, &revs->pending, mode);
 139 }
 140
 141 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 142 {
 143         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 144 }
 145
 146 void add_head_to_pending(struct rev_info *revs)
 147 {
 148         unsigned char sha1[20];
 149         struct object *obj;
 150         if (get_sha1("HEAD", sha1))
 151                 return;
 152         obj = parse_object(sha1);
 153         if (!obj)
 154                 return;
 155         add_pending_object(revs, obj, "HEAD");
 156 }
 157
 158 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 159 {
 160         struct object *object;
 161
 162         object = parse_object(sha1);
 163         if (!object)
 164                 die("bad object %s", name);
 165         object->flags |= flags;
 166         return object;
 167 }
 168
 169 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 170 {
 171         unsigned long flags = object->flags;
 172
 173         /*
 174          * Tag object? Look what it points to..
 175          */
 176         while (object->type == OBJ_TAG) {
 177                 struct tag *tag = (struct tag *) object;
 178                 if (revs->tag_objects && !(flags & UNINTERESTING))
 179                         add_pending_object(revs, object, tag->tag);
 180                 if (!tag->tagged)
 181                         die("bad tag");
 182                 object = parse_object(tag->tagged->sha1);
 183                 if (!object)
 184                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 185         }
 186
 187         /*
 188          * Commit object? Just return it, we'll do all the complex
 189          * reachability crud.
 190          */
 191         if (object->type == OBJ_COMMIT) {
 192                 struct commit *commit = (struct commit *)object;
 193                 if (parse_commit(commit) < 0)
 194                         die("unable to parse commit %s", name);
 195                 if (flags & UNINTERESTING) {
 196                         commit->object.flags |= UNINTERESTING;
 197                         mark_parents_uninteresting(commit);
 198                         revs->limited = 1;
 199                 }
 200                 return commit;
 201         }
 202
 203         /*
 204          * Tree object? Either mark it uniniteresting, or add it
 205          * to the list of objects to look at later..
 206          */
 207         if (object->type == OBJ_TREE) {
 208                 struct tree *tree = (struct tree *)object;
 209                 if (!revs->tree_objects)
 210                         return NULL;
 211                 if (flags & UNINTERESTING) {
 212                         mark_tree_uninteresting(tree);
 213                         return NULL;
 214                 }
 215                 add_pending_object(revs, object, "");
 216                 return NULL;
 217         }
 218
 219         /*
 220          * Blob object? You know the drill by now..
 221          */
 222         if (object->type == OBJ_BLOB) {
 223                 struct blob *blob = (struct blob *)object;
 224                 if (!revs->blob_objects)
 225                         return NULL;
 226                 if (flags & UNINTERESTING) {
 227                         mark_blob_uninteresting(blob);
 228                         return NULL;
 229                 }
 230                 add_pending_object(revs, object, "");
 231                 return NULL;
 232         }
 233         die("%s is unknown object", name);
 234 }
 235
 236 static int everybody_uninteresting(struct commit_list *orig)
 237 {
 238         struct commit_list *list = orig;
 239         while (list) {
 240                 struct commit *commit = list->item;
 241                 list = list->next;
 242                 if (commit->object.flags & UNINTERESTING)
 243                         continue;
 244                 return 0;
 245         }
 246         return 1;
 247 }
 248
 249 /*
 250  * The goal is to get REV_TREE_NEW as the result only if the
 251  * diff consists of all '+' (and no other changes), and
 252  * REV_TREE_DIFFERENT otherwise (of course if the trees are
 253  * the same we want REV_TREE_SAME).  That means that once we
 254  * get to REV_TREE_DIFFERENT, we do not have to look any further.
 255  */
 256 static int tree_difference = REV_TREE_SAME;
 257
 258 static void file_add_remove(struct diff_options *options,
 259                     int addremove, unsigned mode,
 260                     const unsigned char *sha1,
 261                     const char *base, const char *path)
 262 {
 263         int diff = REV_TREE_DIFFERENT;
 264
 265         /*
 266          * Is it an add of a new file? It means that the old tree
 267          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 268          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 269          * (and if it already was "REV_TREE_NEW", we'll keep it
 270          * "REV_TREE_NEW" of course).
 271          */
 272         if (addremove == '+') {
 273                 diff = tree_difference;
 274                 if (diff != REV_TREE_SAME)
 275                         return;
 276                 diff = REV_TREE_NEW;
 277         }
 278         tree_difference = diff;
 279         if (tree_difference == REV_TREE_DIFFERENT)
 280                 DIFF_OPT_SET(options, HAS_CHANGES);
 281 }
 282
 283 static void file_change(struct diff_options *options,
 284                  unsigned old_mode, unsigned new_mode,
 285                  const unsigned char *old_sha1,
 286                  const unsigned char *new_sha1,
 287                  const char *base, const char *path)
 288 {
 289         tree_difference = REV_TREE_DIFFERENT;
 290         DIFF_OPT_SET(options, HAS_CHANGES);
 291 }
 292
 293 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 294 {
 295         if (!t1)
 296                 return REV_TREE_NEW;
 297         if (!t2)
 298                 return REV_TREE_DIFFERENT;
 299         tree_difference = REV_TREE_SAME;
 300         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 301         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 302                            &revs->pruning) < 0)
 303                 return REV_TREE_DIFFERENT;
 304         return tree_difference;
 305 }
 306
 307 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 308 {
 309         int retval;
 310         void *tree;
 311         unsigned long size;
 312         struct tree_desc empty, real;
 313
 314         if (!t1)
 315                 return 0;
 316
 317         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 318         if (!tree)
 319                 return 0;
 320         init_tree_desc(&real, tree, size);
 321         init_tree_desc(&empty, "", 0);
 322
 323         tree_difference = REV_TREE_SAME;
 324         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 325         retval = diff_tree(&empty, &real, "", &revs->pruning);
 326         free(tree);
 327
 328         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 329 }
 330
 331 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 332 {
 333         struct commit_list **pp, *parent;
 334         int tree_changed = 0, tree_same = 0;
 335
 336         /*
 337          * If we don't do pruning, everything is interesting
 338          */
 339         if (!revs->prune)
 340                 return;
 341
 342         if (!commit->tree)
 343                 return;
 344
 345         if (!commit->parents) {
 346                 if (rev_same_tree_as_empty(revs, commit->tree))
 347                         commit->object.flags |= TREESAME;
 348                 return;
 349         }
 350
 351         /*
 352          * Normal non-merge commit? If we don't want to make the
 353          * history dense, we consider it always to be a change..
 354          */
 355         if (!revs->dense && !commit->parents->next)
 356                 return;
 357
 358         pp = &commit->parents;
 359         while ((parent = *pp) != NULL) {
 360                 struct commit *p = parent->item;
 361
 362                 if (parse_commit(p) < 0)
 363                         die("cannot simplify commit %s (because of %s)",
 364                             sha1_to_hex(commit->object.sha1),
 365                             sha1_to_hex(p->object.sha1));
 366                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 367                 case REV_TREE_SAME:
 368                         tree_same = 1;
 369                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 370                                 /* Even if a merge with an uninteresting
 371                                  * side branch brought the entire change
 372                                  * we are interested in, we do not want
 373                                  * to lose the other branches of this
 374                                  * merge, so we just keep going.
 375                                  */
 376                                 pp = &parent->next;
 377                                 continue;
 378                         }
 379                         parent->next = NULL;
 380                         commit->parents = parent;
 381                         commit->object.flags |= TREESAME;
 382                         return;
 383
 384                 case REV_TREE_NEW:
 385                         if (revs->remove_empty_trees &&
 386                             rev_same_tree_as_empty(revs, p->tree)) {
 387                                 /* We are adding all the specified
 388                                  * paths from this parent, so the
 389                                  * history beyond this parent is not
 390                                  * interesting.  Remove its parents
 391                                  * (they are grandparents for us).
 392                                  * IOW, we pretend this parent is a
 393                                  * "root" commit.
 394                                  */
 395                                 if (parse_commit(p) < 0)
 396                                         die("cannot simplify commit %s (invalid %s)",
 397                                             sha1_to_hex(commit->object.sha1),
 398                                             sha1_to_hex(p->object.sha1));
 399                                 p->parents = NULL;
 400                         }
 401                 /* fallthrough */
 402                 case REV_TREE_DIFFERENT:
 403                         tree_changed = 1;
 404                         pp = &parent->next;
 405                         continue;
 406                 }
 407                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 408         }
 409         if (tree_changed && !tree_same)
 410                 return;
 411         commit->object.flags |= TREESAME;
 412 }
 413
 414 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 415 {
 416         struct commit_list *parent = commit->parents;
 417         unsigned left_flag;
 418         int add, rest;
 419
 420         if (commit->object.flags & ADDED)
 421                 return 0;
 422         commit->object.flags |= ADDED;
 423
 424         /*
 425          * If the commit is uninteresting, don't try to
 426          * prune parents - we want the maximal uninteresting
 427          * set.
 428          *
 429          * Normally we haven't parsed the parent
 430          * yet, so we won't have a parent of a parent
 431          * here. However, it may turn out that we've
 432          * reached this commit some other way (where it
 433          * wasn't uninteresting), in which case we need
 434          * to mark its parents recursively too..
 435          */
 436         if (commit->object.flags & UNINTERESTING) {
 437                 while (parent) {
 438                         struct commit *p = parent->item;
 439                         parent = parent->next;
 440                         if (parse_commit(p) < 0)
 441                                 return -1;
 442                         p->object.flags |= UNINTERESTING;
 443                         if (p->parents)
 444                                 mark_parents_uninteresting(p);
 445                         if (p->object.flags & SEEN)
 446                                 continue;
 447                         p->object.flags |= SEEN;
 448                         insert_by_date(p, list);
 449                 }
 450                 return 0;
 451         }
 452
 453         /*
 454          * Ok, the commit wasn't uninteresting. Try to
 455          * simplify the commit history and find the parent
 456          * that has no differences in the path set if one exists.
 457          */
 458         try_to_simplify_commit(revs, commit);
 459
 460         if (revs->no_walk)
 461                 return 0;
 462
 463         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 464
 465         rest = !revs->first_parent_only;
 466         for (parent = commit->parents, add = 1; parent; add = rest) {
 467                 struct commit *p = parent->item;
 468
 469                 parent = parent->next;
 470                 if (parse_commit(p) < 0)
 471                         return -1;
 472                 p->object.flags |= left_flag;
 473                 if (p->object.flags & SEEN)
 474                         continue;
 475                 p->object.flags |= SEEN;
 476                 if (add)
 477                         insert_by_date(p, list);
 478         }
 479         return 0;
 480 }
 481
 482 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 483 {
 484         struct commit_list *p;
 485         int left_count = 0, right_count = 0;
 486         int left_first;
 487         struct patch_ids ids;
 488
 489         /* First count the commits on the left and on the right */
 490         for (p = list; p; p = p->next) {
 491                 struct commit *commit = p->item;
 492                 unsigned flags = commit->object.flags;
 493                 if (flags & BOUNDARY)
 494                         ;
 495                 else if (flags & SYMMETRIC_LEFT)
 496                         left_count++;
 497                 else
 498                         right_count++;
 499         }
 500
 501         left_first = left_count < right_count;
 502         init_patch_ids(&ids);
 503         if (revs->diffopt.nr_paths) {
 504                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 505                 ids.diffopts.paths = revs->diffopt.paths;
 506                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 507         }
 508
 509         /* Compute patch-ids for one side */
 510         for (p = list; p; p = p->next) {
 511                 struct commit *commit = p->item;
 512                 unsigned flags = commit->object.flags;
 513
 514                 if (flags & BOUNDARY)
 515                         continue;
 516                 /*
 517                  * If we have fewer left, left_first is set and we omit
 518                  * commits on the right branch in this loop.  If we have
 519                  * fewer right, we skip the left ones.
 520                  */
 521                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 522                         continue;
 523                 commit->util = add_commit_patch_id(commit, &ids);
 524         }
 525
 526         /* Check the other side */
 527         for (p = list; p; p = p->next) {
 528                 struct commit *commit = p->item;
 529                 struct patch_id *id;
 530                 unsigned flags = commit->object.flags;
 531
 532                 if (flags & BOUNDARY)
 533                         continue;
 534                 /*
 535                  * If we have fewer left, left_first is set and we omit
 536                  * commits on the left branch in this loop.
 537                  */
 538                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 539                         continue;
 540
 541                 /*
 542                  * Have we seen the same patch id?
 543                  */
 544                 id = has_commit_patch_id(commit, &ids);
 545                 if (!id)
 546                         continue;
 547                 id->seen = 1;
 548                 commit->object.flags |= SHOWN;
 549         }
 550
 551         /* Now check the original side for seen ones */
 552         for (p = list; p; p = p->next) {
 553                 struct commit *commit = p->item;
 554                 struct patch_id *ent;
 555
 556                 ent = commit->util;
 557                 if (!ent)
 558                         continue;
 559                 if (ent->seen)
 560                         commit->object.flags |= SHOWN;
 561                 commit->util = NULL;
 562         }
 563
 564         free_patch_ids(&ids);
 565 }
 566
 567 /* How many extra uninteresting commits we want to see.. */
 568 #define SLOP 5
 569
 570 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 571 {
 572         /*
 573          * No source list at all? We're definitely done..
 574          */
 575         if (!src)
 576                 return 0;
 577
 578         /*
 579          * Does the destination list contain entries with a date
 580          * before the source list? Definitely _not_ done.
 581          */
 582         if (date < src->item->date)
 583                 return SLOP;
 584
 585         /*
 586          * Does the source list still have interesting commits in
 587          * it? Definitely not done..
 588          */
 589         if (!everybody_uninteresting(src))
 590                 return SLOP;
 591
 592         /* Ok, we're closing in.. */
 593         return slop-1;
 594 }
 595
 596 static int limit_list(struct rev_info *revs)
 597 {
 598         int slop = SLOP;
 599         unsigned long date = ~0ul;
 600         struct commit_list *list = revs->commits;
 601         struct commit_list *newlist = NULL;
 602         struct commit_list **p = &newlist;
 603
 604         while (list) {
 605                 struct commit_list *entry = list;
 606                 struct commit *commit = list->item;
 607                 struct object *obj = &commit->object;
 608                 show_early_output_fn_t show;
 609
 610                 list = list->next;
 611                 free(entry);
 612
 613                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 614                         obj->flags |= UNINTERESTING;
 615                 if (add_parents_to_list(revs, commit, &list) < 0)
 616                         return -1;
 617                 if (obj->flags & UNINTERESTING) {
 618                         mark_parents_uninteresting(commit);
 619                         if (revs->show_all)
 620                                 p = &commit_list_insert(commit, p)->next;
 621                         slop = still_interesting(list, date, slop);
 622                         if (slop)
 623                                 continue;
 624                         /* If showing all, add the whole pending list to the end */
 625                         if (revs->show_all)
 626                                 *p = list;
 627                         break;
 628                 }
 629                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 630                         continue;
 631                 date = commit->date;
 632                 p = &commit_list_insert(commit, p)->next;
 633
 634                 show = show_early_output;
 635                 if (!show)
 636                         continue;
 637
 638                 show(revs, newlist);
 639                 show_early_output = NULL;
 640         }
 641         if (revs->cherry_pick)
 642                 cherry_pick_list(newlist, revs);
 643
 644         revs->commits = newlist;
 645         return 0;
 646 }
 647
 648 struct all_refs_cb {
 649         int all_flags;
 650         int warned_bad_reflog;
 651         struct rev_info *all_revs;
 652         const char *name_for_errormsg;
 653 };
 654
 655 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 656 {
 657         struct all_refs_cb *cb = cb_data;
 658         struct object *object = get_reference(cb->all_revs, path, sha1,
 659                                               cb->all_flags);
 660         add_pending_object(cb->all_revs, object, path);
 661         return 0;
 662 }
 663
 664 static void handle_refs(struct rev_info *revs, unsigned flags,
 665                 int (*for_each)(each_ref_fn, void *))
 666 {
 667         struct all_refs_cb cb;
 668         cb.all_revs = revs;
 669         cb.all_flags = flags;
 670         for_each(handle_one_ref, &cb);
 671 }
 672
 673 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 674 {
 675         struct all_refs_cb *cb = cb_data;
 676         if (!is_null_sha1(sha1)) {
 677                 struct object *o = parse_object(sha1);
 678                 if (o) {
 679                         o->flags |= cb->all_flags;
 680                         add_pending_object(cb->all_revs, o, "");
 681                 }
 682                 else if (!cb->warned_bad_reflog) {
 683                         warning("reflog of '%s' references pruned commits",
 684                                 cb->name_for_errormsg);
 685                         cb->warned_bad_reflog = 1;
 686                 }
 687         }
 688 }
 689
 690 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 691                 const char *email, unsigned long timestamp, int tz,
 692                 const char *message, void *cb_data)
 693 {
 694         handle_one_reflog_commit(osha1, cb_data);
 695         handle_one_reflog_commit(nsha1, cb_data);
 696         return 0;
 697 }
 698
 699 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 700 {
 701         struct all_refs_cb *cb = cb_data;
 702         cb->warned_bad_reflog = 0;
 703         cb->name_for_errormsg = path;
 704         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 705         return 0;
 706 }
 707
 708 static void handle_reflog(struct rev_info *revs, unsigned flags)
 709 {
 710         struct all_refs_cb cb;
 711         cb.all_revs = revs;
 712         cb.all_flags = flags;
 713         for_each_reflog(handle_one_reflog, &cb);
 714 }
 715
 716 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 717 {
 718         unsigned char sha1[20];
 719         struct object *it;
 720         struct commit *commit;
 721         struct commit_list *parents;
 722
 723         if (*arg == '^') {
 724                 flags ^= UNINTERESTING;
 725                 arg++;
 726         }
 727         if (get_sha1(arg, sha1))
 728                 return 0;
 729         while (1) {
 730                 it = get_reference(revs, arg, sha1, 0);
 731                 if (it->type != OBJ_TAG)
 732                         break;
 733                 if (!((struct tag*)it)->tagged)
 734                         return 0;
 735                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 736         }
 737         if (it->type != OBJ_COMMIT)
 738                 return 0;
 739         commit = (struct commit *)it;
 740         for (parents = commit->parents; parents; parents = parents->next) {
 741                 it = &parents->item->object;
 742                 it->flags |= flags;
 743                 add_pending_object(revs, it, arg);
 744         }
 745         return 1;
 746 }
 747
 748 void init_revisions(struct rev_info *revs, const char *prefix)
 749 {
 750         memset(revs, 0, sizeof(*revs));
 751
 752         revs->abbrev = DEFAULT_ABBREV;
 753         revs->ignore_merges = 1;
 754         revs->simplify_history = 1;
 755         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 756         DIFF_OPT_SET(&revs->pruning, QUIET);
 757         revs->pruning.add_remove = file_add_remove;
 758         revs->pruning.change = file_change;
 759         revs->lifo = 1;
 760         revs->dense = 1;
 761         revs->prefix = prefix;
 762         revs->max_age = -1;
 763         revs->min_age = -1;
 764         revs->skip_count = -1;
 765         revs->max_count = -1;
 766
 767         revs->commit_format = CMIT_FMT_DEFAULT;
 768
 769         diff_setup(&revs->diffopt);
 770         if (prefix && !revs->diffopt.prefix) {
 771                 revs->diffopt.prefix = prefix;
 772                 revs->diffopt.prefix_length = strlen(prefix);
 773         }
 774 }
 775
 776 static void add_pending_commit_list(struct rev_info *revs,
 777                                     struct commit_list *commit_list,
 778                                     unsigned int flags)
 779 {
 780         while (commit_list) {
 781                 struct object *object = &commit_list->item->object;
 782                 object->flags |= flags;
 783                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 784                 commit_list = commit_list->next;
 785         }
 786 }
 787
 788 static void prepare_show_merge(struct rev_info *revs)
 789 {
 790         struct commit_list *bases;
 791         struct commit *head, *other;
 792         unsigned char sha1[20];
 793         const char **prune = NULL;
 794         int i, prune_num = 1; /* counting terminating NULL */
 795
 796         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 797                 die("--merge without HEAD?");
 798         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 799                 die("--merge without MERGE_HEAD?");
 800         add_pending_object(revs, &head->object, "HEAD");
 801         add_pending_object(revs, &other->object, "MERGE_HEAD");
 802         bases = get_merge_bases(head, other, 1);
 803         add_pending_commit_list(revs, bases, UNINTERESTING);
 804         free_commit_list(bases);
 805         head->object.flags |= SYMMETRIC_LEFT;
 806
 807         if (!active_nr)
 808                 read_cache();
 809         for (i = 0; i < active_nr; i++) {
 810                 struct cache_entry *ce = active_cache[i];
 811                 if (!ce_stage(ce))
 812                         continue;
 813                 if (ce_path_match(ce, revs->prune_data)) {
 814                         prune_num++;
 815                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 816                         prune[prune_num-2] = ce->name;
 817                         prune[prune_num-1] = NULL;
 818                 }
 819                 while ((i+1 < active_nr) &&
 820                        ce_same_name(ce, active_cache[i+1]))
 821                         i++;
 822         }
 823         revs->prune_data = prune;
 824         revs->limited = 1;
 825 }
 826
 827 int handle_revision_arg(const char *arg, struct rev_info *revs,
 828                         int flags,
 829                         int cant_be_filename)
 830 {
 831         unsigned mode;
 832         char *dotdot;
 833         struct object *object;
 834         unsigned char sha1[20];
 835         int local_flags;
 836
 837         dotdot = strstr(arg, "..");
 838         if (dotdot) {
 839                 unsigned char from_sha1[20];
 840                 const char *next = dotdot + 2;
 841                 const char *this = arg;
 842                 int symmetric = *next == '.';
 843                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 844
 845                 *dotdot = 0;
 846                 next += symmetric;
 847
 848                 if (!*next)
 849                         next = "HEAD";
 850                 if (dotdot == arg)
 851                         this = "HEAD";
 852                 if (!get_sha1(this, from_sha1) &&
 853                     !get_sha1(next, sha1)) {
 854                         struct commit *a, *b;
 855                         struct commit_list *exclude;
 856
 857                         a = lookup_commit_reference(from_sha1);
 858                         b = lookup_commit_reference(sha1);
 859                         if (!a || !b) {
 860                                 die(symmetric ?
 861                                     "Invalid symmetric difference expression %s...%s" :
 862                                     "Invalid revision range %s..%s",
 863                                     arg, next);
 864                         }
 865
 866                         if (!cant_be_filename) {
 867                                 *dotdot = '.';
 868                                 verify_non_filename(revs->prefix, arg);
 869                         }
 870
 871                         if (symmetric) {
 872                                 exclude = get_merge_bases(a, b, 1);
 873                                 add_pending_commit_list(revs, exclude,
 874                                                         flags_exclude);
 875                                 free_commit_list(exclude);
 876                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 877                         } else
 878                                 a->object.flags |= flags_exclude;
 879                         b->object.flags |= flags;
 880                         add_pending_object(revs, &a->object, this);
 881                         add_pending_object(revs, &b->object, next);
 882                         return 0;
 883                 }
 884                 *dotdot = '.';
 885         }
 886         dotdot = strstr(arg, "^@");
 887         if (dotdot && !dotdot[2]) {
 888                 *dotdot = 0;
 889                 if (add_parents_only(revs, arg, flags))
 890                         return 0;
 891                 *dotdot = '^';
 892         }
 893         dotdot = strstr(arg, "^!");
 894         if (dotdot && !dotdot[2]) {
 895                 *dotdot = 0;
 896                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 897                         *dotdot = '^';
 898         }
 899
 900         local_flags = 0;
 901         if (*arg == '^') {
 902                 local_flags = UNINTERESTING;
 903                 arg++;
 904         }
 905         if (get_sha1_with_mode(arg, sha1, &mode))
 906                 return -1;
 907         if (!cant_be_filename)
 908                 verify_non_filename(revs->prefix, arg);
 909         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 910         add_pending_object_with_mode(revs, object, arg, mode);
 911         return 0;
 912 }
 913
 914 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 915 {
 916         if (!revs->grep_filter) {
 917                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 918                 opt->status_only = 1;
 919                 opt->pattern_tail = &(opt->pattern_list);
 920                 opt->regflags = REG_NEWLINE;
 921                 revs->grep_filter = opt;
 922         }
 923         append_grep_pattern(revs->grep_filter, ptn,
 924                             "command line", 0, what);
 925 }
 926
 927 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 928 {
 929         char *pat;
 930         const char *prefix;
 931         int patlen, fldlen;
 932
 933         fldlen = strlen(field);
 934         patlen = strlen(pattern);
 935         pat = xmalloc(patlen + fldlen + 10);
 936         prefix = ".*";
 937         if (*pattern == '^') {
 938                 prefix = "";
 939                 pattern++;
 940         }
 941         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 942         add_grep(revs, pat, GREP_PATTERN_HEAD);
 943 }
 944
 945 static void add_message_grep(struct rev_info *revs, const char *pattern)
 946 {
 947         add_grep(revs, pattern, GREP_PATTERN_BODY);
 948 }
 949
 950 static void add_ignore_packed(struct rev_info *revs, const char *name)
 951 {
 952         int num = ++revs->num_ignore_packed;
 953
 954         revs->ignore_packed = xrealloc(revs->ignore_packed,
 955                                        sizeof(const char **) * (num + 1));
 956         revs->ignore_packed[num-1] = name;
 957         revs->ignore_packed[num] = NULL;
 958 }
 959
 960 /*
 961  * Parse revision information, filling in the "rev_info" structure,
 962  * and removing the used arguments from the argument list.
 963  *
 964  * Returns the number of arguments left that weren't recognized
 965  * (which are also moved to the head of the argument list)
 966  */
 967 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 968 {
 969         int i, flags, seen_dashdash, show_merge;
 970         const char **unrecognized = argv + 1;
 971         int left = 1;
 972         int all_match = 0;
 973         int regflags = 0;
 974         int fixed = 0;
 975
 976         /* First, search for "--" */
 977         seen_dashdash = 0;
 978         for (i = 1; i < argc; i++) {
 979                 const char *arg = argv[i];
 980                 if (strcmp(arg, "--"))
 981                         continue;
 982                 argv[i] = NULL;
 983                 argc = i;
 984                 if (argv[i + 1])
 985                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 986                 seen_dashdash = 1;
 987                 break;
 988         }
 989
 990         flags = show_merge = 0;
 991         for (i = 1; i < argc; i++) {
 992                 const char *arg = argv[i];
 993                 if (*arg == '-') {
 994                         int opts;
 995                         if (!prefixcmp(arg, "--max-count=")) {
 996                                 revs->max_count = atoi(arg + 12);
 997                                 continue;
 998                         }
 999                         if (!prefixcmp(arg, "--skip=")) {
1000                                 revs->skip_count = atoi(arg + 7);
1001                                 continue;
1002                         }
1003                         /* accept -<digit>, like traditional "head" */
1004                         if ((*arg == '-') && isdigit(arg[1])) {
1005                                 revs->max_count = atoi(arg + 1);
1006                                 continue;
1007                         }
1008                         if (!strcmp(arg, "-n")) {
1009                                 if (argc <= i + 1)
1010                                         die("-n requires an argument");
1011                                 revs->max_count = atoi(argv[++i]);
1012                                 continue;
1013                         }
1014                         if (!prefixcmp(arg, "-n")) {
1015                                 revs->max_count = atoi(arg + 2);
1016                                 continue;
1017                         }
1018                         if (!prefixcmp(arg, "--max-age=")) {
1019                                 revs->max_age = atoi(arg + 10);
1020                                 continue;
1021                         }
1022                         if (!prefixcmp(arg, "--since=")) {
1023                                 revs->max_age = approxidate(arg + 8);
1024                                 continue;
1025                         }
1026                         if (!prefixcmp(arg, "--after=")) {
1027                                 revs->max_age = approxidate(arg + 8);
1028                                 continue;
1029                         }
1030                         if (!prefixcmp(arg, "--min-age=")) {
1031                                 revs->min_age = atoi(arg + 10);
1032                                 continue;
1033                         }
1034                         if (!prefixcmp(arg, "--before=")) {
1035                                 revs->min_age = approxidate(arg + 9);
1036                                 continue;
1037                         }
1038                         if (!prefixcmp(arg, "--until=")) {
1039                                 revs->min_age = approxidate(arg + 8);
1040                                 continue;
1041                         }
1042                         if (!strcmp(arg, "--all")) {
1043                                 handle_refs(revs, flags, for_each_ref);
1044                                 continue;
1045                         }
1046                         if (!strcmp(arg, "--branches")) {
1047                                 handle_refs(revs, flags, for_each_branch_ref);
1048                                 continue;
1049                         }
1050                         if (!strcmp(arg, "--tags")) {
1051                                 handle_refs(revs, flags, for_each_tag_ref);
1052                                 continue;
1053                         }
1054                         if (!strcmp(arg, "--remotes")) {
1055                                 handle_refs(revs, flags, for_each_remote_ref);
1056                                 continue;
1057                         }
1058                         if (!strcmp(arg, "--first-parent")) {
1059                                 revs->first_parent_only = 1;
1060                                 continue;
1061                         }
1062                         if (!strcmp(arg, "--reflog")) {
1063                                 handle_reflog(revs, flags);
1064                                 continue;
1065                         }
1066                         if (!strcmp(arg, "-g") ||
1067                                         !strcmp(arg, "--walk-reflogs")) {
1068                                 init_reflog_walk(&revs->reflog_info);
1069                                 continue;
1070                         }
1071                         if (!strcmp(arg, "--not")) {
1072                                 flags ^= UNINTERESTING;
1073                                 continue;
1074                         }
1075                         if (!strcmp(arg, "--default")) {
1076                                 if (++i >= argc)
1077                                         die("bad --default argument");
1078                                 def = argv[i];
1079                                 continue;
1080                         }
1081                         if (!strcmp(arg, "--merge")) {
1082                                 show_merge = 1;
1083                                 continue;
1084                         }
1085                         if (!strcmp(arg, "--topo-order")) {
1086                                 revs->lifo = 1;
1087                                 revs->topo_order = 1;
1088                                 continue;
1089                         }
1090                         if (!strcmp(arg, "--date-order")) {
1091                                 revs->lifo = 0;
1092                                 revs->topo_order = 1;
1093                                 continue;
1094                         }
1095                         if (!prefixcmp(arg, "--early-output")) {
1096                                 int count = 100;
1097                                 switch (arg[14]) {
1098                                 case '=':
1099                                         count = atoi(arg+15);
1100                                         /* Fallthrough */
1101                                 case 0:
1102                                         revs->topo_order = 1;
1103                                         revs->early_output = count;
1104                                         continue;
1105                                 }
1106                         }
1107                         if (!strcmp(arg, "--parents")) {
1108                                 revs->rewrite_parents = 1;
1109                                 revs->print_parents = 1;
1110                                 continue;
1111                         }
1112                         if (!strcmp(arg, "--dense")) {
1113                                 revs->dense = 1;
1114                                 continue;
1115                         }
1116                         if (!strcmp(arg, "--sparse")) {
1117                                 revs->dense = 0;
1118                                 continue;
1119                         }
1120                         if (!strcmp(arg, "--show-all")) {
1121                                 revs->show_all = 1;
1122                                 continue;
1123                         }
1124                         if (!strcmp(arg, "--remove-empty")) {
1125                                 revs->remove_empty_trees = 1;
1126                                 continue;
1127                         }
1128                         if (!strcmp(arg, "--no-merges")) {
1129                                 revs->no_merges = 1;
1130                                 continue;
1131                         }
1132                         if (!strcmp(arg, "--boundary")) {
1133                                 revs->boundary = 1;
1134                                 continue;
1135                         }
1136                         if (!strcmp(arg, "--left-right")) {
1137                                 revs->left_right = 1;
1138                                 continue;
1139                         }
1140                         if (!strcmp(arg, "--cherry-pick")) {
1141                                 revs->cherry_pick = 1;
1142                                 revs->limited = 1;
1143                                 continue;
1144                         }
1145                         if (!strcmp(arg, "--objects")) {
1146                                 revs->tag_objects = 1;
1147                                 revs->tree_objects = 1;
1148                                 revs->blob_objects = 1;
1149                                 continue;
1150                         }
1151                         if (!strcmp(arg, "--objects-edge")) {
1152                                 revs->tag_objects = 1;
1153                                 revs->tree_objects = 1;
1154                                 revs->blob_objects = 1;
1155                                 revs->edge_hint = 1;
1156                                 continue;
1157                         }
1158                         if (!strcmp(arg, "--unpacked")) {
1159                                 revs->unpacked = 1;
1160                                 free(revs->ignore_packed);
1161                                 revs->ignore_packed = NULL;
1162                                 revs->num_ignore_packed = 0;
1163                                 continue;
1164                         }
1165                         if (!prefixcmp(arg, "--unpacked=")) {
1166                                 revs->unpacked = 1;
1167                                 add_ignore_packed(revs, arg+11);
1168                                 continue;
1169                         }
1170                         if (!strcmp(arg, "-r")) {
1171                                 revs->diff = 1;
1172                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1173                                 continue;
1174                         }
1175                         if (!strcmp(arg, "-t")) {
1176                                 revs->diff = 1;
1177                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1178                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1179                                 continue;
1180                         }
1181                         if (!strcmp(arg, "-m")) {
1182                                 revs->ignore_merges = 0;
1183                                 continue;
1184                         }
1185                         if (!strcmp(arg, "-c")) {
1186                                 revs->diff = 1;
1187                                 revs->dense_combined_merges = 0;
1188                                 revs->combine_merges = 1;
1189                                 continue;
1190                         }
1191                         if (!strcmp(arg, "--cc")) {
1192                                 revs->diff = 1;
1193                                 revs->dense_combined_merges = 1;
1194                                 revs->combine_merges = 1;
1195                                 continue;
1196                         }
1197                         if (!strcmp(arg, "-v")) {
1198                                 revs->verbose_header = 1;
1199                                 continue;
1200                         }
1201                         if (!prefixcmp(arg, "--pretty")) {
1202                                 revs->verbose_header = 1;
1203                                 get_commit_format(arg+8, revs);
1204                                 continue;
1205                         }
1206                         if (!strcmp(arg, "--root")) {
1207                                 revs->show_root_diff = 1;
1208                                 continue;
1209                         }
1210                         if (!strcmp(arg, "--no-commit-id")) {
1211                                 revs->no_commit_id = 1;
1212                                 continue;
1213                         }
1214                         if (!strcmp(arg, "--always")) {
1215                                 revs->always_show_header = 1;
1216                                 continue;
1217                         }
1218                         if (!strcmp(arg, "--no-abbrev")) {
1219                                 revs->abbrev = 0;
1220                                 continue;
1221                         }
1222                         if (!strcmp(arg, "--abbrev")) {
1223                                 revs->abbrev = DEFAULT_ABBREV;
1224                                 continue;
1225                         }
1226                         if (!prefixcmp(arg, "--abbrev=")) {
1227                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1228                                 if (revs->abbrev < MINIMUM_ABBREV)
1229                                         revs->abbrev = MINIMUM_ABBREV;
1230                                 else if (revs->abbrev > 40)
1231                                         revs->abbrev = 40;
1232                                 continue;
1233                         }
1234                         if (!strcmp(arg, "--abbrev-commit")) {
1235                                 revs->abbrev_commit = 1;
1236                                 continue;
1237                         }
1238                         if (!strcmp(arg, "--full-diff")) {
1239                                 revs->diff = 1;
1240                                 revs->full_diff = 1;
1241                                 continue;
1242                         }
1243                         if (!strcmp(arg, "--full-history")) {
1244                                 revs->simplify_history = 0;
1245                                 continue;
1246                         }
1247                         if (!strcmp(arg, "--relative-date")) {
1248                                 revs->date_mode = DATE_RELATIVE;
1249                                 continue;
1250                         }
1251                         if (!strncmp(arg, "--date=", 7)) {
1252                                 revs->date_mode = parse_date_format(arg + 7);
1253                                 continue;
1254                         }
1255                         if (!strcmp(arg, "--log-size")) {
1256                                 revs->show_log_size = 1;
1257                                 continue;
1258                         }
1259
1260                         /*
1261                          * Grepping the commit log
1262                          */
1263                         if (!prefixcmp(arg, "--author=")) {
1264                                 add_header_grep(revs, "author", arg+9);
1265                                 continue;
1266                         }
1267                         if (!prefixcmp(arg, "--committer=")) {
1268                                 add_header_grep(revs, "committer", arg+12);
1269                                 continue;
1270                         }
1271                         if (!prefixcmp(arg, "--grep=")) {
1272                                 add_message_grep(revs, arg+7);
1273                                 continue;
1274                         }
1275                         if (!strcmp(arg, "--extended-regexp") ||
1276                             !strcmp(arg, "-E")) {
1277                                 regflags |= REG_EXTENDED;
1278                                 continue;
1279                         }
1280                         if (!strcmp(arg, "--regexp-ignore-case") ||
1281                             !strcmp(arg, "-i")) {
1282                                 regflags |= REG_ICASE;
1283                                 continue;
1284                         }
1285                         if (!strcmp(arg, "--fixed-strings") ||
1286                             !strcmp(arg, "-F")) {
1287                                 fixed = 1;
1288                                 continue;
1289                         }
1290                         if (!strcmp(arg, "--all-match")) {
1291                                 all_match = 1;
1292                                 continue;
1293                         }
1294                         if (!prefixcmp(arg, "--encoding=")) {
1295                                 arg += 11;
1296                                 if (strcmp(arg, "none"))
1297                                         git_log_output_encoding = xstrdup(arg);
1298                                 else
1299                                         git_log_output_encoding = "";
1300                                 continue;
1301                         }
1302                         if (!strcmp(arg, "--reverse")) {
1303                                 revs->reverse ^= 1;
1304                                 continue;
1305                         }
1306                         if (!strcmp(arg, "--no-walk")) {
1307                                 revs->no_walk = 1;
1308                                 continue;
1309                         }
1310                         if (!strcmp(arg, "--do-walk")) {
1311                                 revs->no_walk = 0;
1312                                 continue;
1313                         }
1314
1315                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1316                         if (opts > 0) {
1317                                 i += opts - 1;
1318                                 continue;
1319                         }
1320                         *unrecognized++ = arg;
1321                         left++;
1322                         continue;
1323                 }
1324
1325                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1326                         int j;
1327                         if (seen_dashdash || *arg == '^')
1328                                 die("bad revision '%s'", arg);
1329
1330                         /* If we didn't have a "--":
1331                          * (1) all filenames must exist;
1332                          * (2) all rev-args must not be interpretable
1333                          *     as a valid filename.
1334                          * but the latter we have checked in the main loop.
1335                          */
1336                         for (j = i; j < argc; j++)
1337                                 verify_filename(revs->prefix, argv[j]);
1338
1339                         revs->prune_data = get_pathspec(revs->prefix,
1340                                                         argv + i);
1341                         break;
1342                 }
1343         }
1344
1345         if (revs->grep_filter) {
1346                 revs->grep_filter->regflags |= regflags;
1347                 revs->grep_filter->fixed = fixed;
1348         }
1349
1350         if (show_merge)
1351                 prepare_show_merge(revs);
1352         if (def && !revs->pending.nr) {
1353                 unsigned char sha1[20];
1354                 struct object *object;
1355                 unsigned mode;
1356                 if (get_sha1_with_mode(def, sha1, &mode))
1357                         die("bad default revision '%s'", def);
1358                 object = get_reference(revs, def, sha1, 0);
1359                 add_pending_object_with_mode(revs, object, def, mode);
1360         }
1361
1362         /* Did the user ask for any diff output? Run the diff! */
1363         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1364                 revs->diff = 1;
1365
1366         /* Pickaxe, diff-filter and rename following need diffs */
1367         if (revs->diffopt.pickaxe ||
1368             revs->diffopt.filter ||
1369             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1370                 revs->diff = 1;
1371
1372         if (revs->topo_order)
1373                 revs->limited = 1;
1374
1375         if (revs->prune_data) {
1376                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1377                 /* Can't prune commits with rename following: the paths change.. */
1378                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1379                         revs->prune = 1;
1380                 if (!revs->full_diff)
1381                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1382         }
1383         if (revs->combine_merges) {
1384                 revs->ignore_merges = 0;
1385                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1386                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1387         }
1388         revs->diffopt.abbrev = revs->abbrev;
1389         if (diff_setup_done(&revs->diffopt) < 0)
1390                 die("diff_setup_done failed");
1391
1392         if (revs->grep_filter) {
1393                 revs->grep_filter->all_match = all_match;
1394                 compile_grep_patterns(revs->grep_filter);
1395         }
1396
1397         if (revs->reverse && revs->reflog_info)
1398                 die("cannot combine --reverse with --walk-reflogs");
1399
1400         return left;
1401 }
1402
1403 int prepare_revision_walk(struct rev_info *revs)
1404 {
1405         int nr = revs->pending.nr;
1406         struct object_array_entry *e, *list;
1407
1408         e = list = revs->pending.objects;
1409         revs->pending.nr = 0;
1410         revs->pending.alloc = 0;
1411         revs->pending.objects = NULL;
1412         while (--nr >= 0) {
1413                 struct commit *commit = handle_commit(revs, e->item, e->name);
1414                 if (commit) {
1415                         if (!(commit->object.flags & SEEN)) {
1416                                 commit->object.flags |= SEEN;
1417                                 insert_by_date(commit, &revs->commits);
1418                         }
1419                 }
1420                 e++;
1421         }
1422         free(list);
1423
1424         if (revs->no_walk)
1425                 return 0;
1426         if (revs->limited)
1427                 if (limit_list(revs) < 0)
1428                         return -1;
1429         if (revs->topo_order)
1430                 sort_in_topological_order(&revs->commits, revs->lifo);
1431         return 0;
1432 }
1433
1434 enum rewrite_result {
1435         rewrite_one_ok,
1436         rewrite_one_noparents,
1437         rewrite_one_error,
1438 };
1439
1440 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1441 {
1442         for (;;) {
1443                 struct commit *p = *pp;
1444                 if (!revs->limited)
1445                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1446                                 return rewrite_one_error;
1447                 if (p->parents && p->parents->next)
1448                         return rewrite_one_ok;
1449                 if (p->object.flags & UNINTERESTING)
1450                         return rewrite_one_ok;
1451                 if (!(p->object.flags & TREESAME))
1452                         return rewrite_one_ok;
1453                 if (!p->parents)
1454                         return rewrite_one_noparents;
1455                 *pp = p->parents->item;
1456         }
1457 }
1458
1459 static void remove_duplicate_parents(struct commit *commit)
1460 {
1461         struct commit_list **pp, *p;
1462
1463         /* Examine existing parents while marking ones we have seen... */
1464         pp = &commit->parents;
1465         while ((p = *pp) != NULL) {
1466                 struct commit *parent = p->item;
1467                 if (parent->object.flags & TMP_MARK) {
1468                         *pp = p->next;
1469                         continue;
1470                 }
1471                 parent->object.flags |= TMP_MARK;
1472                 pp = &p->next;
1473         }
1474         /* ... and clear the temporary mark */
1475         for (p = commit->parents; p; p = p->next)
1476                 p->item->object.flags &= ~TMP_MARK;
1477 }
1478
1479 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1480 {
1481         struct commit_list **pp = &commit->parents;
1482         while (*pp) {
1483                 struct commit_list *parent = *pp;
1484                 switch (rewrite_one(revs, &parent->item)) {
1485                 case rewrite_one_ok:
1486                         break;
1487                 case rewrite_one_noparents:
1488                         *pp = parent->next;
1489                         continue;
1490                 case rewrite_one_error:
1491                         return -1;
1492                 }
1493                 pp = &parent->next;
1494         }
1495         remove_duplicate_parents(commit);
1496         return 0;
1497 }
1498
1499 static int commit_match(struct commit *commit, struct rev_info *opt)
1500 {
1501         if (!opt->grep_filter)
1502                 return 1;
1503         return grep_buffer(opt->grep_filter,
1504                            NULL, /* we say nothing, not even filename */
1505                            commit->buffer, strlen(commit->buffer));
1506 }
1507
1508 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1509 {
1510         if (commit->object.flags & SHOWN)
1511                 return commit_ignore;
1512         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1513                 return commit_ignore;
1514         if (revs->show_all)
1515                 return commit_show;
1516         if (commit->object.flags & UNINTERESTING)
1517                 return commit_ignore;
1518         if (revs->min_age != -1 && (commit->date > revs->min_age))
1519                 return commit_ignore;
1520         if (revs->no_merges && commit->parents && commit->parents->next)
1521                 return commit_ignore;
1522         if (!commit_match(commit, revs))
1523                 return commit_ignore;
1524         if (revs->prune && revs->dense) {
1525                 /* Commit without changes? */
1526                 if (commit->object.flags & TREESAME) {
1527                         /* drop merges unless we want parenthood */
1528                         if (!revs->rewrite_parents)
1529                                 return commit_ignore;
1530                         /* non-merge - always ignore it */
1531                         if (!commit->parents || !commit->parents->next)
1532                                 return commit_ignore;
1533                 }
1534                 if (revs->rewrite_parents && rewrite_parents(revs, commit) < 0)
1535                         return commit_error;
1536         }
1537         return commit_show;
1538 }
1539
1540 static struct commit *get_revision_1(struct rev_info *revs)
1541 {
1542         if (!revs->commits)
1543                 return NULL;
1544
1545         do {
1546                 struct commit_list *entry = revs->commits;
1547                 struct commit *commit = entry->item;
1548
1549                 revs->commits = entry->next;
1550                 free(entry);
1551
1552                 if (revs->reflog_info)
1553                         fake_reflog_parent(revs->reflog_info, commit);
1554
1555                 /*
1556                  * If we haven't done the list limiting, we need to look at
1557                  * the parents here. We also need to do the date-based limiting
1558                  * that we'd otherwise have done in limit_list().
1559                  */
1560                 if (!revs->limited) {
1561                         if (revs->max_age != -1 &&
1562                             (commit->date < revs->max_age))
1563                                 continue;
1564                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1565                                 return NULL;
1566                 }
1567
1568                 switch (simplify_commit(revs, commit)) {
1569                 case commit_ignore:
1570                         continue;
1571                 case commit_error:
1572                         return NULL;
1573                 default:
1574                         return commit;
1575                 }
1576         } while (revs->commits);
1577         return NULL;
1578 }
1579
1580 static void gc_boundary(struct object_array *array)
1581 {
1582         unsigned nr = array->nr;
1583         unsigned alloc = array->alloc;
1584         struct object_array_entry *objects = array->objects;
1585
1586         if (alloc <= nr) {
1587                 unsigned i, j;
1588                 for (i = j = 0; i < nr; i++) {
1589                         if (objects[i].item->flags & SHOWN)
1590                                 continue;
1591                         if (i != j)
1592                                 objects[j] = objects[i];
1593                         j++;
1594                 }
1595                 for (i = j; i < nr; i++)
1596                         objects[i].item = NULL;
1597                 array->nr = j;
1598         }
1599 }
1600
1601 struct commit *get_revision(struct rev_info *revs)
1602 {
1603         struct commit *c = NULL;
1604         struct commit_list *l;
1605
1606         if (revs->boundary == 2) {
1607                 unsigned i;
1608                 struct object_array *array = &revs->boundary_commits;
1609                 struct object_array_entry *objects = array->objects;
1610                 for (i = 0; i < array->nr; i++) {
1611                         c = (struct commit *)(objects[i].item);
1612                         if (!c)
1613                                 continue;
1614                         if (!(c->object.flags & CHILD_SHOWN))
1615                                 continue;
1616                         if (!(c->object.flags & SHOWN))
1617                                 break;
1618                 }
1619                 if (array->nr <= i)
1620                         return NULL;
1621
1622                 c->object.flags |= SHOWN | BOUNDARY;
1623                 return c;
1624         }
1625
1626         if (revs->reverse) {
1627                 int limit = -1;
1628
1629                 if (0 <= revs->max_count) {
1630                         limit = revs->max_count;
1631                         if (0 < revs->skip_count)
1632                                 limit += revs->skip_count;
1633                 }
1634                 l = NULL;
1635                 while ((c = get_revision_1(revs))) {
1636                         commit_list_insert(c, &l);
1637                         if ((0 < limit) && !--limit)
1638                                 break;
1639                 }
1640                 revs->commits = l;
1641                 revs->reverse = 0;
1642                 revs->max_count = -1;
1643                 c = NULL;
1644         }
1645
1646         /*
1647          * Now pick up what they want to give us
1648          */
1649         c = get_revision_1(revs);
1650         if (c) {
1651                 while (0 < revs->skip_count) {
1652                         revs->skip_count--;
1653                         c = get_revision_1(revs);
1654                         if (!c)
1655                                 break;
1656                 }
1657         }
1658
1659         /*
1660          * Check the max_count.
1661          */
1662         switch (revs->max_count) {
1663         case -1:
1664                 break;
1665         case 0:
1666                 c = NULL;
1667                 break;
1668         default:
1669                 revs->max_count--;
1670         }
1671
1672         if (c)
1673                 c->object.flags |= SHOWN;
1674
1675         if (!revs->boundary) {
1676                 return c;
1677         }
1678
1679         if (!c) {
1680                 /*
1681                  * get_revision_1() runs out the commits, and
1682                  * we are done computing the boundaries.
1683                  * switch to boundary commits output mode.
1684                  */
1685                 revs->boundary = 2;
1686                 return get_revision(revs);
1687         }
1688
1689         /*
1690          * boundary commits are the commits that are parents of the
1691          * ones we got from get_revision_1() but they themselves are
1692          * not returned from get_revision_1().  Before returning
1693          * 'c', we need to mark its parents that they could be boundaries.
1694          */
1695
1696         for (l = c->parents; l; l = l->next) {
1697                 struct object *p;
1698                 p = &(l->item->object);
1699                 if (p->flags & (CHILD_SHOWN | SHOWN))
1700                         continue;
1701                 p->flags |= CHILD_SHOWN;
1702                 gc_boundary(&revs->boundary_commits);
1703                 add_object_array(p, NULL, &revs->boundary_commits);
1704         }
1705
1706         return c;
1707 }