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