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