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
 419         if (commit->object.flags & ADDED)
 420                 return 0;
 421         commit->object.flags |= ADDED;
 422
 423         /*
 424          * If the commit is uninteresting, don't try to
 425          * prune parents - we want the maximal uninteresting
 426          * set.
 427          *
 428          * Normally we haven't parsed the parent
 429          * yet, so we won't have a parent of a parent
 430          * here. However, it may turn out that we've
 431          * reached this commit some other way (where it
 432          * wasn't uninteresting), in which case we need
 433          * to mark its parents recursively too..
 434          */
 435         if (commit->object.flags & UNINTERESTING) {
 436                 while (parent) {
 437                         struct commit *p = parent->item;
 438                         parent = parent->next;
 439                         if (parse_commit(p) < 0)
 440                                 return -1;
 441                         p->object.flags |= UNINTERESTING;
 442                         if (p->parents)
 443                                 mark_parents_uninteresting(p);
 444                         if (p->object.flags & SEEN)
 445                                 continue;
 446                         p->object.flags |= SEEN;
 447                         insert_by_date(p, list);
 448                 }
 449                 return 0;
 450         }
 451
 452         /*
 453          * Ok, the commit wasn't uninteresting. Try to
 454          * simplify the commit history and find the parent
 455          * that has no differences in the path set if one exists.
 456          */
 457         try_to_simplify_commit(revs, commit);
 458
 459         if (revs->no_walk)
 460                 return 0;
 461
 462         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 463
 464         for (parent = commit->parents; parent; parent = parent->next) {
 465                 struct commit *p = parent->item;
 466
 467                 if (parse_commit(p) < 0)
 468                         return -1;
 469                 p->object.flags |= left_flag;
 470                 if (!(p->object.flags & SEEN)) {
 471                         p->object.flags |= SEEN;
 472                         insert_by_date(p, list);
 473                 }
 474                 if(revs->first_parent_only)
 475                         break;
 476         }
 477         return 0;
 478 }
 479
 480 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 481 {
 482         struct commit_list *p;
 483         int left_count = 0, right_count = 0;
 484         int left_first;
 485         struct patch_ids ids;
 486
 487         /* First count the commits on the left and on the right */
 488         for (p = list; p; p = p->next) {
 489                 struct commit *commit = p->item;
 490                 unsigned flags = commit->object.flags;
 491                 if (flags & BOUNDARY)
 492                         ;
 493                 else if (flags & SYMMETRIC_LEFT)
 494                         left_count++;
 495                 else
 496                         right_count++;
 497         }
 498
 499         left_first = left_count < right_count;
 500         init_patch_ids(&ids);
 501         if (revs->diffopt.nr_paths) {
 502                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 503                 ids.diffopts.paths = revs->diffopt.paths;
 504                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 505         }
 506
 507         /* Compute patch-ids for one side */
 508         for (p = list; p; p = p->next) {
 509                 struct commit *commit = p->item;
 510                 unsigned flags = commit->object.flags;
 511
 512                 if (flags & BOUNDARY)
 513                         continue;
 514                 /*
 515                  * If we have fewer left, left_first is set and we omit
 516                  * commits on the right branch in this loop.  If we have
 517                  * fewer right, we skip the left ones.
 518                  */
 519                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 520                         continue;
 521                 commit->util = add_commit_patch_id(commit, &ids);
 522         }
 523
 524         /* Check the other side */
 525         for (p = list; p; p = p->next) {
 526                 struct commit *commit = p->item;
 527                 struct patch_id *id;
 528                 unsigned flags = commit->object.flags;
 529
 530                 if (flags & BOUNDARY)
 531                         continue;
 532                 /*
 533                  * If we have fewer left, left_first is set and we omit
 534                  * commits on the left branch in this loop.
 535                  */
 536                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 537                         continue;
 538
 539                 /*
 540                  * Have we seen the same patch id?
 541                  */
 542                 id = has_commit_patch_id(commit, &ids);
 543                 if (!id)
 544                         continue;
 545                 id->seen = 1;
 546                 commit->object.flags |= SHOWN;
 547         }
 548
 549         /* Now check the original side for seen ones */
 550         for (p = list; p; p = p->next) {
 551                 struct commit *commit = p->item;
 552                 struct patch_id *ent;
 553
 554                 ent = commit->util;
 555                 if (!ent)
 556                         continue;
 557                 if (ent->seen)
 558                         commit->object.flags |= SHOWN;
 559                 commit->util = NULL;
 560         }
 561
 562         free_patch_ids(&ids);
 563 }
 564
 565 /* How many extra uninteresting commits we want to see.. */
 566 #define SLOP 5
 567
 568 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 569 {
 570         /*
 571          * No source list at all? We're definitely done..
 572          */
 573         if (!src)
 574                 return 0;
 575
 576         /*
 577          * Does the destination list contain entries with a date
 578          * before the source list? Definitely _not_ done.
 579          */
 580         if (date < src->item->date)
 581                 return SLOP;
 582
 583         /*
 584          * Does the source list still have interesting commits in
 585          * it? Definitely not done..
 586          */
 587         if (!everybody_uninteresting(src))
 588                 return SLOP;
 589
 590         /* Ok, we're closing in.. */
 591         return slop-1;
 592 }
 593
 594 static int limit_list(struct rev_info *revs)
 595 {
 596         int slop = SLOP;
 597         unsigned long date = ~0ul;
 598         struct commit_list *list = revs->commits;
 599         struct commit_list *newlist = NULL;
 600         struct commit_list **p = &newlist;
 601
 602         while (list) {
 603                 struct commit_list *entry = list;
 604                 struct commit *commit = list->item;
 605                 struct object *obj = &commit->object;
 606                 show_early_output_fn_t show;
 607
 608                 list = list->next;
 609                 free(entry);
 610
 611                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 612                         obj->flags |= UNINTERESTING;
 613                 if (add_parents_to_list(revs, commit, &list) < 0)
 614                         return -1;
 615                 if (obj->flags & UNINTERESTING) {
 616                         mark_parents_uninteresting(commit);
 617                         if (revs->show_all)
 618                                 p = &commit_list_insert(commit, p)->next;
 619                         slop = still_interesting(list, date, slop);
 620                         if (slop)
 621                                 continue;
 622                         /* If showing all, add the whole pending list to the end */
 623                         if (revs->show_all)
 624                                 *p = list;
 625                         break;
 626                 }
 627                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 628                         continue;
 629                 date = commit->date;
 630                 p = &commit_list_insert(commit, p)->next;
 631
 632                 show = show_early_output;
 633                 if (!show)
 634                         continue;
 635
 636                 show(revs, newlist);
 637                 show_early_output = NULL;
 638         }
 639         if (revs->cherry_pick)
 640                 cherry_pick_list(newlist, revs);
 641
 642         revs->commits = newlist;
 643         return 0;
 644 }
 645
 646 struct all_refs_cb {
 647         int all_flags;
 648         int warned_bad_reflog;
 649         struct rev_info *all_revs;
 650         const char *name_for_errormsg;
 651 };
 652
 653 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 654 {
 655         struct all_refs_cb *cb = cb_data;
 656         struct object *object = get_reference(cb->all_revs, path, sha1,
 657                                               cb->all_flags);
 658         add_pending_object(cb->all_revs, object, path);
 659         return 0;
 660 }
 661
 662 static void handle_refs(struct rev_info *revs, unsigned flags,
 663                 int (*for_each)(each_ref_fn, void *))
 664 {
 665         struct all_refs_cb cb;
 666         cb.all_revs = revs;
 667         cb.all_flags = flags;
 668         for_each(handle_one_ref, &cb);
 669 }
 670
 671 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 672 {
 673         struct all_refs_cb *cb = cb_data;
 674         if (!is_null_sha1(sha1)) {
 675                 struct object *o = parse_object(sha1);
 676                 if (o) {
 677                         o->flags |= cb->all_flags;
 678                         add_pending_object(cb->all_revs, o, "");
 679                 }
 680                 else if (!cb->warned_bad_reflog) {
 681                         warning("reflog of '%s' references pruned commits",
 682                                 cb->name_for_errormsg);
 683                         cb->warned_bad_reflog = 1;
 684                 }
 685         }
 686 }
 687
 688 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 689                 const char *email, unsigned long timestamp, int tz,
 690                 const char *message, void *cb_data)
 691 {
 692         handle_one_reflog_commit(osha1, cb_data);
 693         handle_one_reflog_commit(nsha1, cb_data);
 694         return 0;
 695 }
 696
 697 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 698 {
 699         struct all_refs_cb *cb = cb_data;
 700         cb->warned_bad_reflog = 0;
 701         cb->name_for_errormsg = path;
 702         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 703         return 0;
 704 }
 705
 706 static void handle_reflog(struct rev_info *revs, unsigned flags)
 707 {
 708         struct all_refs_cb cb;
 709         cb.all_revs = revs;
 710         cb.all_flags = flags;
 711         for_each_reflog(handle_one_reflog, &cb);
 712 }
 713
 714 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 715 {
 716         unsigned char sha1[20];
 717         struct object *it;
 718         struct commit *commit;
 719         struct commit_list *parents;
 720
 721         if (*arg == '^') {
 722                 flags ^= UNINTERESTING;
 723                 arg++;
 724         }
 725         if (get_sha1(arg, sha1))
 726                 return 0;
 727         while (1) {
 728                 it = get_reference(revs, arg, sha1, 0);
 729                 if (it->type != OBJ_TAG)
 730                         break;
 731                 if (!((struct tag*)it)->tagged)
 732                         return 0;
 733                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 734         }
 735         if (it->type != OBJ_COMMIT)
 736                 return 0;
 737         commit = (struct commit *)it;
 738         for (parents = commit->parents; parents; parents = parents->next) {
 739                 it = &parents->item->object;
 740                 it->flags |= flags;
 741                 add_pending_object(revs, it, arg);
 742         }
 743         return 1;
 744 }
 745
 746 void init_revisions(struct rev_info *revs, const char *prefix)
 747 {
 748         memset(revs, 0, sizeof(*revs));
 749
 750         revs->abbrev = DEFAULT_ABBREV;
 751         revs->ignore_merges = 1;
 752         revs->simplify_history = 1;
 753         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 754         DIFF_OPT_SET(&revs->pruning, QUIET);
 755         revs->pruning.add_remove = file_add_remove;
 756         revs->pruning.change = file_change;
 757         revs->lifo = 1;
 758         revs->dense = 1;
 759         revs->prefix = prefix;
 760         revs->max_age = -1;
 761         revs->min_age = -1;
 762         revs->skip_count = -1;
 763         revs->max_count = -1;
 764
 765         revs->commit_format = CMIT_FMT_DEFAULT;
 766
 767         diff_setup(&revs->diffopt);
 768         if (prefix && !revs->diffopt.prefix) {
 769                 revs->diffopt.prefix = prefix;
 770                 revs->diffopt.prefix_length = strlen(prefix);
 771         }
 772 }
 773
 774 static void add_pending_commit_list(struct rev_info *revs,
 775                                     struct commit_list *commit_list,
 776                                     unsigned int flags)
 777 {
 778         while (commit_list) {
 779                 struct object *object = &commit_list->item->object;
 780                 object->flags |= flags;
 781                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 782                 commit_list = commit_list->next;
 783         }
 784 }
 785
 786 static void prepare_show_merge(struct rev_info *revs)
 787 {
 788         struct commit_list *bases;
 789         struct commit *head, *other;
 790         unsigned char sha1[20];
 791         const char **prune = NULL;
 792         int i, prune_num = 1; /* counting terminating NULL */
 793
 794         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 795                 die("--merge without HEAD?");
 796         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 797                 die("--merge without MERGE_HEAD?");
 798         add_pending_object(revs, &head->object, "HEAD");
 799         add_pending_object(revs, &other->object, "MERGE_HEAD");
 800         bases = get_merge_bases(head, other, 1);
 801         add_pending_commit_list(revs, bases, UNINTERESTING);
 802         free_commit_list(bases);
 803         head->object.flags |= SYMMETRIC_LEFT;
 804
 805         if (!active_nr)
 806                 read_cache();
 807         for (i = 0; i < active_nr; i++) {
 808                 struct cache_entry *ce = active_cache[i];
 809                 if (!ce_stage(ce))
 810                         continue;
 811                 if (ce_path_match(ce, revs->prune_data)) {
 812                         prune_num++;
 813                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 814                         prune[prune_num-2] = ce->name;
 815                         prune[prune_num-1] = NULL;
 816                 }
 817                 while ((i+1 < active_nr) &&
 818                        ce_same_name(ce, active_cache[i+1]))
 819                         i++;
 820         }
 821         revs->prune_data = prune;
 822         revs->limited = 1;
 823 }
 824
 825 int handle_revision_arg(const char *arg, struct rev_info *revs,
 826                         int flags,
 827                         int cant_be_filename)
 828 {
 829         unsigned mode;
 830         char *dotdot;
 831         struct object *object;
 832         unsigned char sha1[20];
 833         int local_flags;
 834
 835         dotdot = strstr(arg, "..");
 836         if (dotdot) {
 837                 unsigned char from_sha1[20];
 838                 const char *next = dotdot + 2;
 839                 const char *this = arg;
 840                 int symmetric = *next == '.';
 841                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 842
 843                 *dotdot = 0;
 844                 next += symmetric;
 845
 846                 if (!*next)
 847                         next = "HEAD";
 848                 if (dotdot == arg)
 849                         this = "HEAD";
 850                 if (!get_sha1(this, from_sha1) &&
 851                     !get_sha1(next, sha1)) {
 852                         struct commit *a, *b;
 853                         struct commit_list *exclude;
 854
 855                         a = lookup_commit_reference(from_sha1);
 856                         b = lookup_commit_reference(sha1);
 857                         if (!a || !b) {
 858                                 die(symmetric ?
 859                                     "Invalid symmetric difference expression %s...%s" :
 860                                     "Invalid revision range %s..%s",
 861                                     arg, next);
 862                         }
 863
 864                         if (!cant_be_filename) {
 865                                 *dotdot = '.';
 866                                 verify_non_filename(revs->prefix, arg);
 867                         }
 868
 869                         if (symmetric) {
 870                                 exclude = get_merge_bases(a, b, 1);
 871                                 add_pending_commit_list(revs, exclude,
 872                                                         flags_exclude);
 873                                 free_commit_list(exclude);
 874                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 875                         } else
 876                                 a->object.flags |= flags_exclude;
 877                         b->object.flags |= flags;
 878                         add_pending_object(revs, &a->object, this);
 879                         add_pending_object(revs, &b->object, next);
 880                         return 0;
 881                 }
 882                 *dotdot = '.';
 883         }
 884         dotdot = strstr(arg, "^@");
 885         if (dotdot && !dotdot[2]) {
 886                 *dotdot = 0;
 887                 if (add_parents_only(revs, arg, flags))
 888                         return 0;
 889                 *dotdot = '^';
 890         }
 891         dotdot = strstr(arg, "^!");
 892         if (dotdot && !dotdot[2]) {
 893                 *dotdot = 0;
 894                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 895                         *dotdot = '^';
 896         }
 897
 898         local_flags = 0;
 899         if (*arg == '^') {
 900                 local_flags = UNINTERESTING;
 901                 arg++;
 902         }
 903         if (get_sha1_with_mode(arg, sha1, &mode))
 904                 return -1;
 905         if (!cant_be_filename)
 906                 verify_non_filename(revs->prefix, arg);
 907         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 908         add_pending_object_with_mode(revs, object, arg, mode);
 909         return 0;
 910 }
 911
 912 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 913 {
 914         if (!revs->grep_filter) {
 915                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 916                 opt->status_only = 1;
 917                 opt->pattern_tail = &(opt->pattern_list);
 918                 opt->regflags = REG_NEWLINE;
 919                 revs->grep_filter = opt;
 920         }
 921         append_grep_pattern(revs->grep_filter, ptn,
 922                             "command line", 0, what);
 923 }
 924
 925 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 926 {
 927         char *pat;
 928         const char *prefix;
 929         int patlen, fldlen;
 930
 931         fldlen = strlen(field);
 932         patlen = strlen(pattern);
 933         pat = xmalloc(patlen + fldlen + 10);
 934         prefix = ".*";
 935         if (*pattern == '^') {
 936                 prefix = "";
 937                 pattern++;
 938         }
 939         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 940         add_grep(revs, pat, GREP_PATTERN_HEAD);
 941 }
 942
 943 static void add_message_grep(struct rev_info *revs, const char *pattern)
 944 {
 945         add_grep(revs, pattern, GREP_PATTERN_BODY);
 946 }
 947
 948 static void add_ignore_packed(struct rev_info *revs, const char *name)
 949 {
 950         int num = ++revs->num_ignore_packed;
 951
 952         revs->ignore_packed = xrealloc(revs->ignore_packed,
 953                                        sizeof(const char **) * (num + 1));
 954         revs->ignore_packed[num-1] = name;
 955         revs->ignore_packed[num] = NULL;
 956 }
 957
 958 /*
 959  * Parse revision information, filling in the "rev_info" structure,
 960  * and removing the used arguments from the argument list.
 961  *
 962  * Returns the number of arguments left that weren't recognized
 963  * (which are also moved to the head of the argument list)
 964  */
 965 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 966 {
 967         int i, flags, seen_dashdash, show_merge;
 968         const char **unrecognized = argv + 1;
 969         int left = 1;
 970         int all_match = 0;
 971         int regflags = 0;
 972         int fixed = 0;
 973
 974         /* First, search for "--" */
 975         seen_dashdash = 0;
 976         for (i = 1; i < argc; i++) {
 977                 const char *arg = argv[i];
 978                 if (strcmp(arg, "--"))
 979                         continue;
 980                 argv[i] = NULL;
 981                 argc = i;
 982                 if (argv[i + 1])
 983                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 984                 seen_dashdash = 1;
 985                 break;
 986         }
 987
 988         flags = show_merge = 0;
 989         for (i = 1; i < argc; i++) {
 990                 const char *arg = argv[i];
 991                 if (*arg == '-') {
 992                         int opts;
 993                         if (!prefixcmp(arg, "--max-count=")) {
 994                                 revs->max_count = atoi(arg + 12);
 995                                 continue;
 996                         }
 997                         if (!prefixcmp(arg, "--skip=")) {
 998                                 revs->skip_count = atoi(arg + 7);
 999                                 continue;
1000                         }
1001                         /* accept -<digit>, like traditional "head" */
1002                         if ((*arg == '-') && isdigit(arg[1])) {
1003                                 revs->max_count = atoi(arg + 1);
1004                                 continue;
1005                         }
1006                         if (!strcmp(arg, "-n")) {
1007                                 if (argc <= i + 1)
1008                                         die("-n requires an argument");
1009                                 revs->max_count = atoi(argv[++i]);
1010                                 continue;
1011                         }
1012                         if (!prefixcmp(arg, "-n")) {
1013                                 revs->max_count = atoi(arg + 2);
1014                                 continue;
1015                         }
1016                         if (!prefixcmp(arg, "--max-age=")) {
1017                                 revs->max_age = atoi(arg + 10);
1018                                 continue;
1019                         }
1020                         if (!prefixcmp(arg, "--since=")) {
1021                                 revs->max_age = approxidate(arg + 8);
1022                                 continue;
1023                         }
1024                         if (!prefixcmp(arg, "--after=")) {
1025                                 revs->max_age = approxidate(arg + 8);
1026                                 continue;
1027                         }
1028                         if (!prefixcmp(arg, "--min-age=")) {
1029                                 revs->min_age = atoi(arg + 10);
1030                                 continue;
1031                         }
1032                         if (!prefixcmp(arg, "--before=")) {
1033                                 revs->min_age = approxidate(arg + 9);
1034                                 continue;
1035                         }
1036                         if (!prefixcmp(arg, "--until=")) {
1037                                 revs->min_age = approxidate(arg + 8);
1038                                 continue;
1039                         }
1040                         if (!strcmp(arg, "--all")) {
1041                                 handle_refs(revs, flags, for_each_ref);
1042                                 continue;
1043                         }
1044                         if (!strcmp(arg, "--branches")) {
1045                                 handle_refs(revs, flags, for_each_branch_ref);
1046                                 continue;
1047                         }
1048                         if (!strcmp(arg, "--tags")) {
1049                                 handle_refs(revs, flags, for_each_tag_ref);
1050                                 continue;
1051                         }
1052                         if (!strcmp(arg, "--remotes")) {
1053                                 handle_refs(revs, flags, for_each_remote_ref);
1054                                 continue;
1055                         }
1056                         if (!strcmp(arg, "--first-parent")) {
1057                                 revs->first_parent_only = 1;
1058                                 continue;
1059                         }
1060                         if (!strcmp(arg, "--reflog")) {
1061                                 handle_reflog(revs, flags);
1062                                 continue;
1063                         }
1064                         if (!strcmp(arg, "-g") ||
1065                                         !strcmp(arg, "--walk-reflogs")) {
1066                                 init_reflog_walk(&revs->reflog_info);
1067                                 continue;
1068                         }
1069                         if (!strcmp(arg, "--not")) {
1070                                 flags ^= UNINTERESTING;
1071                                 continue;
1072                         }
1073                         if (!strcmp(arg, "--default")) {
1074                                 if (++i >= argc)
1075                                         die("bad --default argument");
1076                                 def = argv[i];
1077                                 continue;
1078                         }
1079                         if (!strcmp(arg, "--merge")) {
1080                                 show_merge = 1;
1081                                 continue;
1082                         }
1083                         if (!strcmp(arg, "--topo-order")) {
1084                                 revs->lifo = 1;
1085                                 revs->topo_order = 1;
1086                                 continue;
1087                         }
1088                         if (!strcmp(arg, "--date-order")) {
1089                                 revs->lifo = 0;
1090                                 revs->topo_order = 1;
1091                                 continue;
1092                         }
1093                         if (!prefixcmp(arg, "--early-output")) {
1094                                 int count = 100;
1095                                 switch (arg[14]) {
1096                                 case '=':
1097                                         count = atoi(arg+15);
1098                                         /* Fallthrough */
1099                                 case 0:
1100                                         revs->topo_order = 1;
1101                                         revs->early_output = count;
1102                                         continue;
1103                                 }
1104                         }
1105                         if (!strcmp(arg, "--parents")) {
1106                                 revs->parents = 1;
1107                                 continue;
1108                         }
1109                         if (!strcmp(arg, "--dense")) {
1110                                 revs->dense = 1;
1111                                 continue;
1112                         }
1113                         if (!strcmp(arg, "--sparse")) {
1114                                 revs->dense = 0;
1115                                 continue;
1116                         }
1117                         if (!strcmp(arg, "--show-all")) {
1118                                 revs->show_all = 1;
1119                                 continue;
1120                         }
1121                         if (!strcmp(arg, "--remove-empty")) {
1122                                 revs->remove_empty_trees = 1;
1123                                 continue;
1124                         }
1125                         if (!strcmp(arg, "--no-merges")) {
1126                                 revs->no_merges = 1;
1127                                 continue;
1128                         }
1129                         if (!strcmp(arg, "--boundary")) {
1130                                 revs->boundary = 1;
1131                                 continue;
1132                         }
1133                         if (!strcmp(arg, "--left-right")) {
1134                                 revs->left_right = 1;
1135                                 continue;
1136                         }
1137                         if (!strcmp(arg, "--cherry-pick")) {
1138                                 revs->cherry_pick = 1;
1139                                 revs->limited = 1;
1140                                 continue;
1141                         }
1142                         if (!strcmp(arg, "--objects")) {
1143                                 revs->tag_objects = 1;
1144                                 revs->tree_objects = 1;
1145                                 revs->blob_objects = 1;
1146                                 continue;
1147                         }
1148                         if (!strcmp(arg, "--objects-edge")) {
1149                                 revs->tag_objects = 1;
1150                                 revs->tree_objects = 1;
1151                                 revs->blob_objects = 1;
1152                                 revs->edge_hint = 1;
1153                                 continue;
1154                         }
1155                         if (!strcmp(arg, "--unpacked")) {
1156                                 revs->unpacked = 1;
1157                                 free(revs->ignore_packed);
1158                                 revs->ignore_packed = NULL;
1159                                 revs->num_ignore_packed = 0;
1160                                 continue;
1161                         }
1162                         if (!prefixcmp(arg, "--unpacked=")) {
1163                                 revs->unpacked = 1;
1164                                 add_ignore_packed(revs, arg+11);
1165                                 continue;
1166                         }
1167                         if (!strcmp(arg, "-r")) {
1168                                 revs->diff = 1;
1169                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1170                                 continue;
1171                         }
1172                         if (!strcmp(arg, "-t")) {
1173                                 revs->diff = 1;
1174                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1175                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1176                                 continue;
1177                         }
1178                         if (!strcmp(arg, "-m")) {
1179                                 revs->ignore_merges = 0;
1180                                 continue;
1181                         }
1182                         if (!strcmp(arg, "-c")) {
1183                                 revs->diff = 1;
1184                                 revs->dense_combined_merges = 0;
1185                                 revs->combine_merges = 1;
1186                                 continue;
1187                         }
1188                         if (!strcmp(arg, "--cc")) {
1189                                 revs->diff = 1;
1190                                 revs->dense_combined_merges = 1;
1191                                 revs->combine_merges = 1;
1192                                 continue;
1193                         }
1194                         if (!strcmp(arg, "-v")) {
1195                                 revs->verbose_header = 1;
1196                                 continue;
1197                         }
1198                         if (!prefixcmp(arg, "--pretty")) {
1199                                 revs->verbose_header = 1;
1200                                 get_commit_format(arg+8, revs);
1201                                 continue;
1202                         }
1203                         if (!strcmp(arg, "--root")) {
1204                                 revs->show_root_diff = 1;
1205                                 continue;
1206                         }
1207                         if (!strcmp(arg, "--no-commit-id")) {
1208                                 revs->no_commit_id = 1;
1209                                 continue;
1210                         }
1211                         if (!strcmp(arg, "--always")) {
1212                                 revs->always_show_header = 1;
1213                                 continue;
1214                         }
1215                         if (!strcmp(arg, "--no-abbrev")) {
1216                                 revs->abbrev = 0;
1217                                 continue;
1218                         }
1219                         if (!strcmp(arg, "--abbrev")) {
1220                                 revs->abbrev = DEFAULT_ABBREV;
1221                                 continue;
1222                         }
1223                         if (!prefixcmp(arg, "--abbrev=")) {
1224                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1225                                 if (revs->abbrev < MINIMUM_ABBREV)
1226                                         revs->abbrev = MINIMUM_ABBREV;
1227                                 else if (revs->abbrev > 40)
1228                                         revs->abbrev = 40;
1229                                 continue;
1230                         }
1231                         if (!strcmp(arg, "--abbrev-commit")) {
1232                                 revs->abbrev_commit = 1;
1233                                 continue;
1234                         }
1235                         if (!strcmp(arg, "--full-diff")) {
1236                                 revs->diff = 1;
1237                                 revs->full_diff = 1;
1238                                 continue;
1239                         }
1240                         if (!strcmp(arg, "--full-history")) {
1241                                 revs->simplify_history = 0;
1242                                 continue;
1243                         }
1244                         if (!strcmp(arg, "--relative-date")) {
1245                                 revs->date_mode = DATE_RELATIVE;
1246                                 continue;
1247                         }
1248                         if (!strncmp(arg, "--date=", 7)) {
1249                                 revs->date_mode = parse_date_format(arg + 7);
1250                                 continue;
1251                         }
1252                         if (!strcmp(arg, "--log-size")) {
1253                                 revs->show_log_size = 1;
1254                                 continue;
1255                         }
1256
1257                         /*
1258                          * Grepping the commit log
1259                          */
1260                         if (!prefixcmp(arg, "--author=")) {
1261                                 add_header_grep(revs, "author", arg+9);
1262                                 continue;
1263                         }
1264                         if (!prefixcmp(arg, "--committer=")) {
1265                                 add_header_grep(revs, "committer", arg+12);
1266                                 continue;
1267                         }
1268                         if (!prefixcmp(arg, "--grep=")) {
1269                                 add_message_grep(revs, arg+7);
1270                                 continue;
1271                         }
1272                         if (!strcmp(arg, "--extended-regexp") ||
1273                             !strcmp(arg, "-E")) {
1274                                 regflags |= REG_EXTENDED;
1275                                 continue;
1276                         }
1277                         if (!strcmp(arg, "--regexp-ignore-case") ||
1278                             !strcmp(arg, "-i")) {
1279                                 regflags |= REG_ICASE;
1280                                 continue;
1281                         }
1282                         if (!strcmp(arg, "--fixed-strings") ||
1283                             !strcmp(arg, "-F")) {
1284                                 fixed = 1;
1285                                 continue;
1286                         }
1287                         if (!strcmp(arg, "--all-match")) {
1288                                 all_match = 1;
1289                                 continue;
1290                         }
1291                         if (!prefixcmp(arg, "--encoding=")) {
1292                                 arg += 11;
1293                                 if (strcmp(arg, "none"))
1294                                         git_log_output_encoding = xstrdup(arg);
1295                                 else
1296                                         git_log_output_encoding = "";
1297                                 continue;
1298                         }
1299                         if (!strcmp(arg, "--reverse")) {
1300                                 revs->reverse ^= 1;
1301                                 continue;
1302                         }
1303                         if (!strcmp(arg, "--no-walk")) {
1304                                 revs->no_walk = 1;
1305                                 continue;
1306                         }
1307                         if (!strcmp(arg, "--do-walk")) {
1308                                 revs->no_walk = 0;
1309                                 continue;
1310                         }
1311
1312                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1313                         if (opts > 0) {
1314                                 i += opts - 1;
1315                                 continue;
1316                         }
1317                         *unrecognized++ = arg;
1318                         left++;
1319                         continue;
1320                 }
1321
1322                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1323                         int j;
1324                         if (seen_dashdash || *arg == '^')
1325                                 die("bad revision '%s'", arg);
1326
1327                         /* If we didn't have a "--":
1328                          * (1) all filenames must exist;
1329                          * (2) all rev-args must not be interpretable
1330                          *     as a valid filename.
1331                          * but the latter we have checked in the main loop.
1332                          */
1333                         for (j = i; j < argc; j++)
1334                                 verify_filename(revs->prefix, argv[j]);
1335
1336                         revs->prune_data = get_pathspec(revs->prefix,
1337                                                         argv + i);
1338                         break;
1339                 }
1340         }
1341
1342         if (revs->grep_filter) {
1343                 revs->grep_filter->regflags |= regflags;
1344                 revs->grep_filter->fixed = fixed;
1345         }
1346
1347         if (show_merge)
1348                 prepare_show_merge(revs);
1349         if (def && !revs->pending.nr) {
1350                 unsigned char sha1[20];
1351                 struct object *object;
1352                 unsigned mode;
1353                 if (get_sha1_with_mode(def, sha1, &mode))
1354                         die("bad default revision '%s'", def);
1355                 object = get_reference(revs, def, sha1, 0);
1356                 add_pending_object_with_mode(revs, object, def, mode);
1357         }
1358
1359         /* Did the user ask for any diff output? Run the diff! */
1360         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1361                 revs->diff = 1;
1362
1363         /* Pickaxe, diff-filter and rename following need diffs */
1364         if (revs->diffopt.pickaxe ||
1365             revs->diffopt.filter ||
1366             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1367                 revs->diff = 1;
1368
1369         if (revs->topo_order)
1370                 revs->limited = 1;
1371
1372         if (revs->prune_data) {
1373                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1374                 /* Can't prune commits with rename following: the paths change.. */
1375                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1376                         revs->prune = 1;
1377                 if (!revs->full_diff)
1378                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1379         }
1380         if (revs->combine_merges) {
1381                 revs->ignore_merges = 0;
1382                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1383                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1384         }
1385         revs->diffopt.abbrev = revs->abbrev;
1386         if (diff_setup_done(&revs->diffopt) < 0)
1387                 die("diff_setup_done failed");
1388
1389         if (revs->grep_filter) {
1390                 revs->grep_filter->all_match = all_match;
1391                 compile_grep_patterns(revs->grep_filter);
1392         }
1393
1394         if (revs->reverse && revs->reflog_info)
1395                 die("cannot combine --reverse with --walk-reflogs");
1396
1397         return left;
1398 }
1399
1400 int prepare_revision_walk(struct rev_info *revs)
1401 {
1402         int nr = revs->pending.nr;
1403         struct object_array_entry *e, *list;
1404
1405         e = list = revs->pending.objects;
1406         revs->pending.nr = 0;
1407         revs->pending.alloc = 0;
1408         revs->pending.objects = NULL;
1409         while (--nr >= 0) {
1410                 struct commit *commit = handle_commit(revs, e->item, e->name);
1411                 if (commit) {
1412                         if (!(commit->object.flags & SEEN)) {
1413                                 commit->object.flags |= SEEN;
1414                                 insert_by_date(commit, &revs->commits);
1415                         }
1416                 }
1417                 e++;
1418         }
1419         free(list);
1420
1421         if (revs->no_walk)
1422                 return 0;
1423         if (revs->limited)
1424                 if (limit_list(revs) < 0)
1425                         return -1;
1426         if (revs->topo_order)
1427                 sort_in_topological_order(&revs->commits, revs->lifo);
1428         return 0;
1429 }
1430
1431 enum rewrite_result {
1432         rewrite_one_ok,
1433         rewrite_one_noparents,
1434         rewrite_one_error,
1435 };
1436
1437 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1438 {
1439         for (;;) {
1440                 struct commit *p = *pp;
1441                 if (!revs->limited)
1442                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1443                                 return rewrite_one_error;
1444                 if (p->parents && p->parents->next)
1445                         return rewrite_one_ok;
1446                 if (p->object.flags & UNINTERESTING)
1447                         return rewrite_one_ok;
1448                 if (!(p->object.flags & TREESAME))
1449                         return rewrite_one_ok;
1450                 if (!p->parents)
1451                         return rewrite_one_noparents;
1452                 *pp = p->parents->item;
1453         }
1454 }
1455
1456 static void remove_duplicate_parents(struct commit *commit)
1457 {
1458         struct commit_list **pp, *p;
1459
1460         /* Examine existing parents while marking ones we have seen... */
1461         pp = &commit->parents;
1462         while ((p = *pp) != NULL) {
1463                 struct commit *parent = p->item;
1464                 if (parent->object.flags & TMP_MARK) {
1465                         *pp = p->next;
1466                         continue;
1467                 }
1468                 parent->object.flags |= TMP_MARK;
1469                 pp = &p->next;
1470         }
1471         /* ... and clear the temporary mark */
1472         for (p = commit->parents; p; p = p->next)
1473                 p->item->object.flags &= ~TMP_MARK;
1474 }
1475
1476 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1477 {
1478         struct commit_list **pp = &commit->parents;
1479         while (*pp) {
1480                 struct commit_list *parent = *pp;
1481                 switch (rewrite_one(revs, &parent->item)) {
1482                 case rewrite_one_ok:
1483                         break;
1484                 case rewrite_one_noparents:
1485                         *pp = parent->next;
1486                         continue;
1487                 case rewrite_one_error:
1488                         return -1;
1489                 }
1490                 pp = &parent->next;
1491         }
1492         remove_duplicate_parents(commit);
1493         return 0;
1494 }
1495
1496 static int commit_match(struct commit *commit, struct rev_info *opt)
1497 {
1498         if (!opt->grep_filter)
1499                 return 1;
1500         return grep_buffer(opt->grep_filter,
1501                            NULL, /* we say nothing, not even filename */
1502                            commit->buffer, strlen(commit->buffer));
1503 }
1504
1505 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1506 {
1507         if (commit->object.flags & SHOWN)
1508                 return commit_ignore;
1509         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1510                 return commit_ignore;
1511         if (revs->show_all)
1512                 return commit_show;
1513         if (commit->object.flags & UNINTERESTING)
1514                 return commit_ignore;
1515         if (revs->min_age != -1 && (commit->date > revs->min_age))
1516                 return commit_ignore;
1517         if (revs->no_merges && commit->parents && commit->parents->next)
1518                 return commit_ignore;
1519         if (!commit_match(commit, revs))
1520                 return commit_ignore;
1521         if (revs->prune && revs->dense) {
1522                 /* Commit without changes? */
1523                 if (commit->object.flags & TREESAME) {
1524                         /* drop merges unless we want parenthood */
1525                         if (!revs->parents)
1526                                 return commit_ignore;
1527                         /* non-merge - always ignore it */
1528                         if (!commit->parents || !commit->parents->next)
1529                                 return commit_ignore;
1530                 }
1531                 if (revs->parents && rewrite_parents(revs, commit) < 0)
1532                         return commit_error;
1533         }
1534         return commit_show;
1535 }
1536
1537 static struct commit *get_revision_1(struct rev_info *revs)
1538 {
1539         if (!revs->commits)
1540                 return NULL;
1541
1542         do {
1543                 struct commit_list *entry = revs->commits;
1544                 struct commit *commit = entry->item;
1545
1546                 revs->commits = entry->next;
1547                 free(entry);
1548
1549                 if (revs->reflog_info)
1550                         fake_reflog_parent(revs->reflog_info, commit);
1551
1552                 /*
1553                  * If we haven't done the list limiting, we need to look at
1554                  * the parents here. We also need to do the date-based limiting
1555                  * that we'd otherwise have done in limit_list().
1556                  */
1557                 if (!revs->limited) {
1558                         if (revs->max_age != -1 &&
1559                             (commit->date < revs->max_age))
1560                                 continue;
1561                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1562                                 return NULL;
1563                 }
1564
1565                 switch (simplify_commit(revs, commit)) {
1566                 case commit_ignore:
1567                         continue;
1568                 case commit_error:
1569                         return NULL;
1570                 default:
1571                         return commit;
1572                 }
1573         } while (revs->commits);
1574         return NULL;
1575 }
1576
1577 static void gc_boundary(struct object_array *array)
1578 {
1579         unsigned nr = array->nr;
1580         unsigned alloc = array->alloc;
1581         struct object_array_entry *objects = array->objects;
1582
1583         if (alloc <= nr) {
1584                 unsigned i, j;
1585                 for (i = j = 0; i < nr; i++) {
1586                         if (objects[i].item->flags & SHOWN)
1587                                 continue;
1588                         if (i != j)
1589                                 objects[j] = objects[i];
1590                         j++;
1591                 }
1592                 for (i = j; i < nr; i++)
1593                         objects[i].item = NULL;
1594                 array->nr = j;
1595         }
1596 }
1597
1598 struct commit *get_revision(struct rev_info *revs)
1599 {
1600         struct commit *c = NULL;
1601         struct commit_list *l;
1602
1603         if (revs->boundary == 2) {
1604                 unsigned i;
1605                 struct object_array *array = &revs->boundary_commits;
1606                 struct object_array_entry *objects = array->objects;
1607                 for (i = 0; i < array->nr; i++) {
1608                         c = (struct commit *)(objects[i].item);
1609                         if (!c)
1610                                 continue;
1611                         if (!(c->object.flags & CHILD_SHOWN))
1612                                 continue;
1613                         if (!(c->object.flags & SHOWN))
1614                                 break;
1615                 }
1616                 if (array->nr <= i)
1617                         return NULL;
1618
1619                 c->object.flags |= SHOWN | BOUNDARY;
1620                 return c;
1621         }
1622
1623         if (revs->reverse) {
1624                 int limit = -1;
1625
1626                 if (0 <= revs->max_count) {
1627                         limit = revs->max_count;
1628                         if (0 < revs->skip_count)
1629                                 limit += revs->skip_count;
1630                 }
1631                 l = NULL;
1632                 while ((c = get_revision_1(revs))) {
1633                         commit_list_insert(c, &l);
1634                         if ((0 < limit) && !--limit)
1635                                 break;
1636                 }
1637                 revs->commits = l;
1638                 revs->reverse = 0;
1639                 revs->max_count = -1;
1640                 c = NULL;
1641         }
1642
1643         /*
1644          * Now pick up what they want to give us
1645          */
1646         c = get_revision_1(revs);
1647         if (c) {
1648                 while (0 < revs->skip_count) {
1649                         revs->skip_count--;
1650                         c = get_revision_1(revs);
1651                         if (!c)
1652                                 break;
1653                 }
1654         }
1655
1656         /*
1657          * Check the max_count.
1658          */
1659         switch (revs->max_count) {
1660         case -1:
1661                 break;
1662         case 0:
1663                 c = NULL;
1664                 break;
1665         default:
1666                 revs->max_count--;
1667         }
1668
1669         if (c)
1670                 c->object.flags |= SHOWN;
1671
1672         if (!revs->boundary) {
1673                 return c;
1674         }
1675
1676         if (!c) {
1677                 /*
1678                  * get_revision_1() runs out the commits, and
1679                  * we are done computing the boundaries.
1680                  * switch to boundary commits output mode.
1681                  */
1682                 revs->boundary = 2;
1683                 return get_revision(revs);
1684         }
1685
1686         /*
1687          * boundary commits are the commits that are parents of the
1688          * ones we got from get_revision_1() but they themselves are
1689          * not returned from get_revision_1().  Before returning
1690          * 'c', we need to mark its parents that they could be boundaries.
1691          */
1692
1693         for (l = c->parents; l; l = l->next) {
1694                 struct object *p;
1695                 p = &(l->item->object);
1696                 if (p->flags & (CHILD_SHOWN | SHOWN))
1697                         continue;
1698                 p->flags |= CHILD_SHOWN;
1699                 gc_boundary(&revs->boundary_commits);
1700                 add_object_array(p, NULL, &revs->boundary_commits);
1701         }
1702
1703         return c;
1704 }