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