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