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
  10 static char *path_name(struct name_path *path, const char *name)
  11 {
  12         struct name_path *p;
  13         char *n, *m;
  14         int nlen = strlen(name);
  15         int len = nlen + 1;
  16
  17         for (p = path; p; p = p->up) {
  18                 if (p->elem_len)
  19                         len += p->elem_len + 1;
  20         }
  21         n = xmalloc(len);
  22         m = n + len - (nlen + 1);
  23         strcpy(m, name);
  24         for (p = path; p; p = p->up) {
  25                 if (p->elem_len) {
  26                         m -= p->elem_len + 1;
  27                         memcpy(m, p->elem, p->elem_len);
  28                         m[p->elem_len] = '/';
  29                 }
  30         }
  31         return n;
  32 }
  33
  34 void add_object(struct object *obj,
  35                 struct object_array *p,
  36                 struct name_path *path,
  37                 const char *name)
  38 {
  39         add_object_array(obj, path_name(path, name), p);
  40 }
  41
  42 static void mark_blob_uninteresting(struct blob *blob)
  43 {
  44         if (blob->object.flags & UNINTERESTING)
  45                 return;
  46         blob->object.flags |= UNINTERESTING;
  47 }
  48
  49 void mark_tree_uninteresting(struct tree *tree)
  50 {
  51         struct tree_desc desc;
  52         struct name_entry entry;
  53         struct object *obj = &tree->object;
  54
  55         if (obj->flags & UNINTERESTING)
  56                 return;
  57         obj->flags |= UNINTERESTING;
  58         if (!has_sha1_file(obj->sha1))
  59                 return;
  60         if (parse_tree(tree) < 0)
  61                 die("bad tree %s", sha1_to_hex(obj->sha1));
  62
  63         desc.buf = tree->buffer;
  64         desc.size = tree->size;
  65         while (tree_entry(&desc, &entry)) {
  66                 if (S_ISDIR(entry.mode))
  67                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  68                 else
  69                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  70         }
  71
  72         /*
  73          * We don't care about the tree any more
  74          * after it has been marked uninteresting.
  75          */
  76         free(tree->buffer);
  77         tree->buffer = NULL;
  78 }
  79
  80 void mark_parents_uninteresting(struct commit *commit)
  81 {
  82         struct commit_list *parents = commit->parents;
  83
  84         while (parents) {
  85                 struct commit *commit = parents->item;
  86                 if (!(commit->object.flags & UNINTERESTING)) {
  87                         commit->object.flags |= UNINTERESTING;
  88
  89                         /*
  90                          * Normally we haven't parsed the parent
  91                          * yet, so we won't have a parent of a parent
  92                          * here. However, it may turn out that we've
  93                          * reached this commit some other way (where it
  94                          * wasn't uninteresting), in which case we need
  95                          * to mark its parents recursively too..
  96                          */
  97                         if (commit->parents)
  98                                 mark_parents_uninteresting(commit);
  99                 }
 100
 101                 /*
 102                  * A missing commit is ok iff its parent is marked
 103                  * uninteresting.
 104                  *
 105                  * We just mark such a thing parsed, so that when
 106                  * it is popped next time around, we won't be trying
 107                  * to parse it and get an error.
 108                  */
 109                 if (!has_sha1_file(commit->object.sha1))
 110                         commit->object.parsed = 1;
 111                 parents = parents->next;
 112         }
 113 }
 114
 115 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 116 {
 117         add_object_array(obj, name, &revs->pending);
 118 }
 119
 120 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 121 {
 122         struct object *object;
 123
 124         object = parse_object(sha1);
 125         if (!object)
 126                 die("bad object %s", name);
 127         object->flags |= flags;
 128         return object;
 129 }
 130
 131 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 132 {
 133         unsigned long flags = object->flags;
 134
 135         /*
 136          * Tag object? Look what it points to..
 137          */
 138         while (object->type == OBJ_TAG) {
 139                 struct tag *tag = (struct tag *) object;
 140                 if (revs->tag_objects && !(flags & UNINTERESTING))
 141                         add_pending_object(revs, object, tag->tag);
 142                 object = parse_object(tag->tagged->sha1);
 143                 if (!object)
 144                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 145         }
 146
 147         /*
 148          * Commit object? Just return it, we'll do all the complex
 149          * reachability crud.
 150          */
 151         if (object->type == OBJ_COMMIT) {
 152                 struct commit *commit = (struct commit *)object;
 153                 if (parse_commit(commit) < 0)
 154                         die("unable to parse commit %s", name);
 155                 if (flags & UNINTERESTING) {
 156                         commit->object.flags |= UNINTERESTING;
 157                         mark_parents_uninteresting(commit);
 158                         revs->limited = 1;
 159                 }
 160                 return commit;
 161         }
 162
 163         /*
 164          * Tree object? Either mark it uniniteresting, or add it
 165          * to the list of objects to look at later..
 166          */
 167         if (object->type == OBJ_TREE) {
 168                 struct tree *tree = (struct tree *)object;
 169                 if (!revs->tree_objects)
 170                         return NULL;
 171                 if (flags & UNINTERESTING) {
 172                         mark_tree_uninteresting(tree);
 173                         return NULL;
 174                 }
 175                 add_pending_object(revs, object, "");
 176                 return NULL;
 177         }
 178
 179         /*
 180          * Blob object? You know the drill by now..
 181          */
 182         if (object->type == OBJ_BLOB) {
 183                 struct blob *blob = (struct blob *)object;
 184                 if (!revs->blob_objects)
 185                         return NULL;
 186                 if (flags & UNINTERESTING) {
 187                         mark_blob_uninteresting(blob);
 188                         return NULL;
 189                 }
 190                 add_pending_object(revs, object, "");
 191                 return NULL;
 192         }
 193         die("%s is unknown object", name);
 194 }
 195
 196 static int everybody_uninteresting(struct commit_list *orig)
 197 {
 198         struct commit_list *list = orig;
 199         while (list) {
 200                 struct commit *commit = list->item;
 201                 list = list->next;
 202                 if (commit->object.flags & UNINTERESTING)
 203                         continue;
 204                 return 0;
 205         }
 206         return 1;
 207 }
 208
 209 static int tree_difference = REV_TREE_SAME;
 210
 211 static void file_add_remove(struct diff_options *options,
 212                     int addremove, unsigned mode,
 213                     const unsigned char *sha1,
 214                     const char *base, const char *path)
 215 {
 216         int diff = REV_TREE_DIFFERENT;
 217
 218         /*
 219          * Is it an add of a new file? It means that the old tree
 220          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 221          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 222          * (and if it already was "REV_TREE_NEW", we'll keep it
 223          * "REV_TREE_NEW" of course).
 224          */
 225         if (addremove == '+') {
 226                 diff = tree_difference;
 227                 if (diff != REV_TREE_SAME)
 228                         return;
 229                 diff = REV_TREE_NEW;
 230         }
 231         tree_difference = diff;
 232 }
 233
 234 static void file_change(struct diff_options *options,
 235                  unsigned old_mode, unsigned new_mode,
 236                  const unsigned char *old_sha1,
 237                  const unsigned char *new_sha1,
 238                  const char *base, const char *path)
 239 {
 240         tree_difference = REV_TREE_DIFFERENT;
 241 }
 242
 243 int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 244 {
 245         if (!t1)
 246                 return REV_TREE_NEW;
 247         if (!t2)
 248                 return REV_TREE_DIFFERENT;
 249         tree_difference = REV_TREE_SAME;
 250         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 251                            &revs->pruning) < 0)
 252                 return REV_TREE_DIFFERENT;
 253         return tree_difference;
 254 }
 255
 256 int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 257 {
 258         int retval;
 259         void *tree;
 260         struct tree_desc empty, real;
 261
 262         if (!t1)
 263                 return 0;
 264
 265         tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
 266         if (!tree)
 267                 return 0;
 268         real.buf = tree;
 269
 270         empty.buf = "";
 271         empty.size = 0;
 272
 273         tree_difference = 0;
 274         retval = diff_tree(&empty, &real, "", &revs->pruning);
 275         free(tree);
 276
 277         return retval >= 0 && !tree_difference;
 278 }
 279
 280 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 281 {
 282         struct commit_list **pp, *parent;
 283         int tree_changed = 0, tree_same = 0;
 284
 285         if (!commit->tree)
 286                 return;
 287
 288         if (!commit->parents) {
 289                 if (!rev_same_tree_as_empty(revs, commit->tree))
 290                         commit->object.flags |= TREECHANGE;
 291                 return;
 292         }
 293
 294         pp = &commit->parents;
 295         while ((parent = *pp) != NULL) {
 296                 struct commit *p = parent->item;
 297
 298                 parse_commit(p);
 299                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 300                 case REV_TREE_SAME:
 301                         tree_same = 1;
 302                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 303                                 /* Even if a merge with an uninteresting
 304                                  * side branch brought the entire change
 305                                  * we are interested in, we do not want
 306                                  * to lose the other branches of this
 307                                  * merge, so we just keep going.
 308                                  */
 309                                 pp = &parent->next;
 310                                 continue;
 311                         }
 312                         parent->next = NULL;
 313                         commit->parents = parent;
 314                         return;
 315
 316                 case REV_TREE_NEW:
 317                         if (revs->remove_empty_trees &&
 318                             rev_same_tree_as_empty(revs, p->tree)) {
 319                                 /* We are adding all the specified
 320                                  * paths from this parent, so the
 321                                  * history beyond this parent is not
 322                                  * interesting.  Remove its parents
 323                                  * (they are grandparents for us).
 324                                  * IOW, we pretend this parent is a
 325                                  * "root" commit.
 326                                  */
 327                                 parse_commit(p);
 328                                 p->parents = NULL;
 329                         }
 330                 /* fallthrough */
 331                 case REV_TREE_DIFFERENT:
 332                         tree_changed = 1;
 333                         pp = &parent->next;
 334                         continue;
 335                 }
 336                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 337         }
 338         if (tree_changed && !tree_same)
 339                 commit->object.flags |= TREECHANGE;
 340 }
 341
 342 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 343 {
 344         struct commit_list *parent = commit->parents;
 345
 346         if (commit->object.flags & ADDED)
 347                 return;
 348         commit->object.flags |= ADDED;
 349
 350         /*
 351          * If the commit is uninteresting, don't try to
 352          * prune parents - we want the maximal uninteresting
 353          * set.
 354          *
 355          * Normally we haven't parsed the parent
 356          * yet, so we won't have a parent of a parent
 357          * here. However, it may turn out that we've
 358          * reached this commit some other way (where it
 359          * wasn't uninteresting), in which case we need
 360          * to mark its parents recursively too..
 361          */
 362         if (commit->object.flags & UNINTERESTING) {
 363                 while (parent) {
 364                         struct commit *p = parent->item;
 365                         parent = parent->next;
 366                         parse_commit(p);
 367                         p->object.flags |= UNINTERESTING;
 368                         if (p->parents)
 369                                 mark_parents_uninteresting(p);
 370                         if (p->object.flags & SEEN)
 371                                 continue;
 372                         p->object.flags |= SEEN;
 373                         insert_by_date(p, list);
 374                 }
 375                 return;
 376         }
 377
 378         /*
 379          * Ok, the commit wasn't uninteresting. Try to
 380          * simplify the commit history and find the parent
 381          * that has no differences in the path set if one exists.
 382          */
 383         if (revs->prune_fn)
 384                 revs->prune_fn(revs, commit);
 385
 386         if (revs->no_walk)
 387                 return;
 388
 389         parent = commit->parents;
 390         while (parent) {
 391                 struct commit *p = parent->item;
 392
 393                 parent = parent->next;
 394
 395                 parse_commit(p);
 396                 if (p->object.flags & SEEN)
 397                         continue;
 398                 p->object.flags |= SEEN;
 399                 insert_by_date(p, list);
 400         }
 401 }
 402
 403 static void limit_list(struct rev_info *revs)
 404 {
 405         struct commit_list *list = revs->commits;
 406         struct commit_list *newlist = NULL;
 407         struct commit_list **p = &newlist;
 408
 409         while (list) {
 410                 struct commit_list *entry = list;
 411                 struct commit *commit = list->item;
 412                 struct object *obj = &commit->object;
 413
 414                 list = list->next;
 415                 free(entry);
 416
 417                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 418                         obj->flags |= UNINTERESTING;
 419                 if (revs->unpacked &&
 420                     has_sha1_pack(obj->sha1, revs->ignore_packed))
 421                         obj->flags |= UNINTERESTING;
 422                 add_parents_to_list(revs, commit, &list);
 423                 if (obj->flags & UNINTERESTING) {
 424                         mark_parents_uninteresting(commit);
 425                         if (everybody_uninteresting(list))
 426                                 break;
 427                         continue;
 428                 }
 429                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 430                         continue;
 431                 p = &commit_list_insert(commit, p)->next;
 432         }
 433         if (revs->boundary) {
 434                 /* mark the ones that are on the result list first */
 435                 for (list = newlist; list; list = list->next) {
 436                         struct commit *commit = list->item;
 437                         commit->object.flags |= TMP_MARK;
 438                 }
 439                 for (list = newlist; list; list = list->next) {
 440                         struct commit *commit = list->item;
 441                         struct object *obj = &commit->object;
 442                         struct commit_list *parent;
 443                         if (obj->flags & UNINTERESTING)
 444                                 continue;
 445                         for (parent = commit->parents;
 446                              parent;
 447                              parent = parent->next) {
 448                                 struct commit *pcommit = parent->item;
 449                                 if (!(pcommit->object.flags & UNINTERESTING))
 450                                         continue;
 451                                 pcommit->object.flags |= BOUNDARY;
 452                                 if (pcommit->object.flags & TMP_MARK)
 453                                         continue;
 454                                 pcommit->object.flags |= TMP_MARK;
 455                                 p = &commit_list_insert(pcommit, p)->next;
 456                         }
 457                 }
 458                 for (list = newlist; list; list = list->next) {
 459                         struct commit *commit = list->item;
 460                         commit->object.flags &= ~TMP_MARK;
 461                 }
 462         }
 463         revs->commits = newlist;
 464 }
 465
 466 static int all_flags;
 467 static struct rev_info *all_revs;
 468
 469 static int handle_one_ref(const char *path, const unsigned char *sha1)
 470 {
 471         struct object *object = get_reference(all_revs, path, sha1, all_flags);
 472         add_pending_object(all_revs, object, "");
 473         return 0;
 474 }
 475
 476 static void handle_all(struct rev_info *revs, unsigned flags)
 477 {
 478         all_revs = revs;
 479         all_flags = flags;
 480         for_each_ref(handle_one_ref);
 481 }
 482
 483 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 484 {
 485         unsigned char sha1[20];
 486         struct object *it;
 487         struct commit *commit;
 488         struct commit_list *parents;
 489
 490         if (*arg == '^') {
 491                 flags ^= UNINTERESTING;
 492                 arg++;
 493         }
 494         if (get_sha1(arg, sha1))
 495                 return 0;
 496         while (1) {
 497                 it = get_reference(revs, arg, sha1, 0);
 498                 if (it->type != OBJ_TAG)
 499                         break;
 500                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 501         }
 502         if (it->type != OBJ_COMMIT)
 503                 return 0;
 504         commit = (struct commit *)it;
 505         for (parents = commit->parents; parents; parents = parents->next) {
 506                 it = &parents->item->object;
 507                 it->flags |= flags;
 508                 add_pending_object(revs, it, arg);
 509         }
 510         return 1;
 511 }
 512
 513 void init_revisions(struct rev_info *revs, const char *prefix)
 514 {
 515         memset(revs, 0, sizeof(*revs));
 516
 517         revs->abbrev = DEFAULT_ABBREV;
 518         revs->ignore_merges = 1;
 519         revs->simplify_history = 1;
 520         revs->pruning.recursive = 1;
 521         revs->pruning.add_remove = file_add_remove;
 522         revs->pruning.change = file_change;
 523         revs->lifo = 1;
 524         revs->dense = 1;
 525         revs->prefix = prefix;
 526         revs->max_age = -1;
 527         revs->min_age = -1;
 528         revs->max_count = -1;
 529
 530         revs->prune_fn = NULL;
 531         revs->prune_data = NULL;
 532
 533         revs->topo_setter = topo_sort_default_setter;
 534         revs->topo_getter = topo_sort_default_getter;
 535
 536         revs->commit_format = CMIT_FMT_DEFAULT;
 537
 538         diff_setup(&revs->diffopt);
 539 }
 540
 541 static void add_pending_commit_list(struct rev_info *revs,
 542                                     struct commit_list *commit_list,
 543                                     unsigned int flags)
 544 {
 545         while (commit_list) {
 546                 struct object *object = &commit_list->item->object;
 547                 object->flags |= flags;
 548                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 549                 commit_list = commit_list->next;
 550         }
 551 }
 552
 553 static void prepare_show_merge(struct rev_info *revs)
 554 {
 555         struct commit_list *bases;
 556         struct commit *head, *other;
 557         unsigned char sha1[20];
 558         const char **prune = NULL;
 559         int i, prune_num = 1; /* counting terminating NULL */
 560
 561         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 562                 die("--merge without HEAD?");
 563         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 564                 die("--merge without MERGE_HEAD?");
 565         add_pending_object(revs, &head->object, "HEAD");
 566         add_pending_object(revs, &other->object, "MERGE_HEAD");
 567         bases = get_merge_bases(head, other, 1);
 568         while (bases) {
 569                 struct commit *it = bases->item;
 570                 struct commit_list *n = bases->next;
 571                 free(bases);
 572                 bases = n;
 573                 it->object.flags |= UNINTERESTING;
 574                 add_pending_object(revs, &it->object, "(merge-base)");
 575         }
 576
 577         if (!active_nr)
 578                 read_cache();
 579         for (i = 0; i < active_nr; i++) {
 580                 struct cache_entry *ce = active_cache[i];
 581                 if (!ce_stage(ce))
 582                         continue;
 583                 if (ce_path_match(ce, revs->prune_data)) {
 584                         prune_num++;
 585                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 586                         prune[prune_num-2] = ce->name;
 587                         prune[prune_num-1] = NULL;
 588                 }
 589                 while ((i+1 < active_nr) &&
 590                        ce_same_name(ce, active_cache[i+1]))
 591                         i++;
 592         }
 593         revs->prune_data = prune;
 594 }
 595
 596 int handle_revision_arg(const char *arg, struct rev_info *revs,
 597                         int flags,
 598                         int cant_be_filename)
 599 {
 600         char *dotdot;
 601         struct object *object;
 602         unsigned char sha1[20];
 603         int local_flags;
 604
 605         dotdot = strstr(arg, "..");
 606         if (dotdot) {
 607                 unsigned char from_sha1[20];
 608                 const char *next = dotdot + 2;
 609                 const char *this = arg;
 610                 int symmetric = *next == '.';
 611                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 612
 613                 *dotdot = 0;
 614                 next += symmetric;
 615
 616                 if (!*next)
 617                         next = "HEAD";
 618                 if (dotdot == arg)
 619                         this = "HEAD";
 620                 if (!get_sha1(this, from_sha1) &&
 621                     !get_sha1(next, sha1)) {
 622                         struct commit *a, *b;
 623                         struct commit_list *exclude;
 624
 625                         a = lookup_commit_reference(from_sha1);
 626                         b = lookup_commit_reference(sha1);
 627                         if (!a || !b) {
 628                                 die(symmetric ?
 629                                     "Invalid symmetric difference expression %s...%s" :
 630                                     "Invalid revision range %s..%s",
 631                                     arg, next);
 632                         }
 633
 634                         if (!cant_be_filename) {
 635                                 *dotdot = '.';
 636                                 verify_non_filename(revs->prefix, arg);
 637                         }
 638
 639                         if (symmetric) {
 640                                 exclude = get_merge_bases(a, b, 1);
 641                                 add_pending_commit_list(revs, exclude,
 642                                                         flags_exclude);
 643                                 free_commit_list(exclude);
 644                                 a->object.flags |= flags;
 645                         } else
 646                                 a->object.flags |= flags_exclude;
 647                         b->object.flags |= flags;
 648                         add_pending_object(revs, &a->object, this);
 649                         add_pending_object(revs, &b->object, next);
 650                         return 0;
 651                 }
 652                 *dotdot = '.';
 653         }
 654         dotdot = strstr(arg, "^@");
 655         if (dotdot && !dotdot[2]) {
 656                 *dotdot = 0;
 657                 if (add_parents_only(revs, arg, flags))
 658                         return 0;
 659                 *dotdot = '^';
 660         }
 661         local_flags = 0;
 662         if (*arg == '^') {
 663                 local_flags = UNINTERESTING;
 664                 arg++;
 665         }
 666         if (get_sha1(arg, sha1))
 667                 return -1;
 668         if (!cant_be_filename)
 669                 verify_non_filename(revs->prefix, arg);
 670         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 671         add_pending_object(revs, object, arg);
 672         return 0;
 673 }
 674
 675 static void add_ignore_packed(struct rev_info *revs, const char *name)
 676 {
 677         int num = ++revs->num_ignore_packed;
 678
 679         revs->ignore_packed = xrealloc(revs->ignore_packed,
 680                                        sizeof(const char **) * (num + 1));
 681         revs->ignore_packed[num-1] = name;
 682         revs->ignore_packed[num] = NULL;
 683 }
 684
 685 /*
 686  * Parse revision information, filling in the "rev_info" structure,
 687  * and removing the used arguments from the argument list.
 688  *
 689  * Returns the number of arguments left that weren't recognized
 690  * (which are also moved to the head of the argument list)
 691  */
 692 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 693 {
 694         int i, flags, seen_dashdash, show_merge;
 695         const char **unrecognized = argv + 1;
 696         int left = 1;
 697
 698         /* First, search for "--" */
 699         seen_dashdash = 0;
 700         for (i = 1; i < argc; i++) {
 701                 const char *arg = argv[i];
 702                 if (strcmp(arg, "--"))
 703                         continue;
 704                 argv[i] = NULL;
 705                 argc = i;
 706                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 707                 seen_dashdash = 1;
 708                 break;
 709         }
 710
 711         flags = show_merge = 0;
 712         for (i = 1; i < argc; i++) {
 713                 const char *arg = argv[i];
 714                 if (*arg == '-') {
 715                         int opts;
 716                         if (!strncmp(arg, "--max-count=", 12)) {
 717                                 revs->max_count = atoi(arg + 12);
 718                                 continue;
 719                         }
 720                         /* accept -<digit>, like traditional "head" */
 721                         if ((*arg == '-') && isdigit(arg[1])) {
 722                                 revs->max_count = atoi(arg + 1);
 723                                 continue;
 724                         }
 725                         if (!strcmp(arg, "-n")) {
 726                                 if (argc <= i + 1)
 727                                         die("-n requires an argument");
 728                                 revs->max_count = atoi(argv[++i]);
 729                                 continue;
 730                         }
 731                         if (!strncmp(arg,"-n",2)) {
 732                                 revs->max_count = atoi(arg + 2);
 733                                 continue;
 734                         }
 735                         if (!strncmp(arg, "--max-age=", 10)) {
 736                                 revs->max_age = atoi(arg + 10);
 737                                 continue;
 738                         }
 739                         if (!strncmp(arg, "--since=", 8)) {
 740                                 revs->max_age = approxidate(arg + 8);
 741                                 continue;
 742                         }
 743                         if (!strncmp(arg, "--after=", 8)) {
 744                                 revs->max_age = approxidate(arg + 8);
 745                                 continue;
 746                         }
 747                         if (!strncmp(arg, "--min-age=", 10)) {
 748                                 revs->min_age = atoi(arg + 10);
 749                                 continue;
 750                         }
 751                         if (!strncmp(arg, "--before=", 9)) {
 752                                 revs->min_age = approxidate(arg + 9);
 753                                 continue;
 754                         }
 755                         if (!strncmp(arg, "--until=", 8)) {
 756                                 revs->min_age = approxidate(arg + 8);
 757                                 continue;
 758                         }
 759                         if (!strcmp(arg, "--all")) {
 760                                 handle_all(revs, flags);
 761                                 continue;
 762                         }
 763                         if (!strcmp(arg, "--not")) {
 764                                 flags ^= UNINTERESTING;
 765                                 continue;
 766                         }
 767                         if (!strcmp(arg, "--default")) {
 768                                 if (++i >= argc)
 769                                         die("bad --default argument");
 770                                 def = argv[i];
 771                                 continue;
 772                         }
 773                         if (!strcmp(arg, "--merge")) {
 774                                 show_merge = 1;
 775                                 continue;
 776                         }
 777                         if (!strcmp(arg, "--topo-order")) {
 778                                 revs->topo_order = 1;
 779                                 continue;
 780                         }
 781                         if (!strcmp(arg, "--date-order")) {
 782                                 revs->lifo = 0;
 783                                 revs->topo_order = 1;
 784                                 continue;
 785                         }
 786                         if (!strcmp(arg, "--parents")) {
 787                                 revs->parents = 1;
 788                                 continue;
 789                         }
 790                         if (!strcmp(arg, "--dense")) {
 791                                 revs->dense = 1;
 792                                 continue;
 793                         }
 794                         if (!strcmp(arg, "--sparse")) {
 795                                 revs->dense = 0;
 796                                 continue;
 797                         }
 798                         if (!strcmp(arg, "--remove-empty")) {
 799                                 revs->remove_empty_trees = 1;
 800                                 continue;
 801                         }
 802                         if (!strcmp(arg, "--no-merges")) {
 803                                 revs->no_merges = 1;
 804                                 continue;
 805                         }
 806                         if (!strcmp(arg, "--boundary")) {
 807                                 revs->boundary = 1;
 808                                 continue;
 809                         }
 810                         if (!strcmp(arg, "--objects")) {
 811                                 revs->tag_objects = 1;
 812                                 revs->tree_objects = 1;
 813                                 revs->blob_objects = 1;
 814                                 continue;
 815                         }
 816                         if (!strcmp(arg, "--objects-edge")) {
 817                                 revs->tag_objects = 1;
 818                                 revs->tree_objects = 1;
 819                                 revs->blob_objects = 1;
 820                                 revs->edge_hint = 1;
 821                                 continue;
 822                         }
 823                         if (!strcmp(arg, "--unpacked")) {
 824                                 revs->unpacked = 1;
 825                                 free(revs->ignore_packed);
 826                                 revs->ignore_packed = NULL;
 827                                 revs->num_ignore_packed = 0;
 828                                 continue;
 829                         }
 830                         if (!strncmp(arg, "--unpacked=", 11)) {
 831                                 revs->unpacked = 1;
 832                                 add_ignore_packed(revs, arg+11);
 833                                 continue;
 834                         }
 835                         if (!strcmp(arg, "-r")) {
 836                                 revs->diff = 1;
 837                                 revs->diffopt.recursive = 1;
 838                                 continue;
 839                         }
 840                         if (!strcmp(arg, "-t")) {
 841                                 revs->diff = 1;
 842                                 revs->diffopt.recursive = 1;
 843                                 revs->diffopt.tree_in_recursive = 1;
 844                                 continue;
 845                         }
 846                         if (!strcmp(arg, "-m")) {
 847                                 revs->ignore_merges = 0;
 848                                 continue;
 849                         }
 850                         if (!strcmp(arg, "-c")) {
 851                                 revs->diff = 1;
 852                                 revs->dense_combined_merges = 0;
 853                                 revs->combine_merges = 1;
 854                                 continue;
 855                         }
 856                         if (!strcmp(arg, "--cc")) {
 857                                 revs->diff = 1;
 858                                 revs->dense_combined_merges = 1;
 859                                 revs->combine_merges = 1;
 860                                 continue;
 861                         }
 862                         if (!strcmp(arg, "-v")) {
 863                                 revs->verbose_header = 1;
 864                                 continue;
 865                         }
 866                         if (!strncmp(arg, "--pretty", 8)) {
 867                                 revs->verbose_header = 1;
 868                                 revs->commit_format = get_commit_format(arg+8);
 869                                 continue;
 870                         }
 871                         if (!strcmp(arg, "--root")) {
 872                                 revs->show_root_diff = 1;
 873                                 continue;
 874                         }
 875                         if (!strcmp(arg, "--no-commit-id")) {
 876                                 revs->no_commit_id = 1;
 877                                 continue;
 878                         }
 879                         if (!strcmp(arg, "--always")) {
 880                                 revs->always_show_header = 1;
 881                                 continue;
 882                         }
 883                         if (!strcmp(arg, "--no-abbrev")) {
 884                                 revs->abbrev = 0;
 885                                 continue;
 886                         }
 887                         if (!strcmp(arg, "--abbrev")) {
 888                                 revs->abbrev = DEFAULT_ABBREV;
 889                                 continue;
 890                         }
 891                         if (!strncmp(arg, "--abbrev=", 9)) {
 892                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
 893                                 if (revs->abbrev < MINIMUM_ABBREV)
 894                                         revs->abbrev = MINIMUM_ABBREV;
 895                                 else if (revs->abbrev > 40)
 896                                         revs->abbrev = 40;
 897                                 continue;
 898                         }
 899                         if (!strcmp(arg, "--abbrev-commit")) {
 900                                 revs->abbrev_commit = 1;
 901                                 continue;
 902                         }
 903                         if (!strcmp(arg, "--full-diff")) {
 904                                 revs->diff = 1;
 905                                 revs->full_diff = 1;
 906                                 continue;
 907                         }
 908                         if (!strcmp(arg, "--full-history")) {
 909                                 revs->simplify_history = 0;
 910                                 continue;
 911                         }
 912                         if (!strcmp(arg, "--relative-date")) {
 913                                 revs->relative_date = 1;
 914                                 continue;
 915                         }
 916                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
 917                         if (opts > 0) {
 918                                 revs->diff = 1;
 919                                 i += opts - 1;
 920                                 continue;
 921                         }
 922                         *unrecognized++ = arg;
 923                         left++;
 924                         continue;
 925                 }
 926
 927                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
 928                         int j;
 929                         if (seen_dashdash || *arg == '^')
 930                                 die("bad revision '%s'", arg);
 931
 932                         /* If we didn't have a "--":
 933                          * (1) all filenames must exist;
 934                          * (2) all rev-args must not be interpretable
 935                          *     as a valid filename.
 936                          * but the latter we have checked in the main loop.
 937                          */
 938                         for (j = i; j < argc; j++)
 939                                 verify_filename(revs->prefix, argv[j]);
 940
 941                         revs->prune_data = get_pathspec(revs->prefix,
 942                                                         argv + i);
 943                         break;
 944                 }
 945         }
 946
 947         if (show_merge)
 948                 prepare_show_merge(revs);
 949         if (def && !revs->pending.nr) {
 950                 unsigned char sha1[20];
 951                 struct object *object;
 952                 if (get_sha1(def, sha1))
 953                         die("bad default revision '%s'", def);
 954                 object = get_reference(revs, def, sha1, 0);
 955                 add_pending_object(revs, object, def);
 956         }
 957
 958         if (revs->topo_order || revs->unpacked)
 959                 revs->limited = 1;
 960
 961         if (revs->prune_data) {
 962                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
 963                 revs->prune_fn = try_to_simplify_commit;
 964                 if (!revs->full_diff)
 965                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
 966         }
 967         if (revs->combine_merges) {
 968                 revs->ignore_merges = 0;
 969                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
 970                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 971         }
 972         revs->diffopt.abbrev = revs->abbrev;
 973         if (diff_setup_done(&revs->diffopt) < 0)
 974                 die("diff_setup_done failed");
 975
 976         return left;
 977 }
 978
 979 void prepare_revision_walk(struct rev_info *revs)
 980 {
 981         int nr = revs->pending.nr;
 982         struct object_array_entry *list = revs->pending.objects;
 983
 984         revs->pending.nr = 0;
 985         revs->pending.alloc = 0;
 986         revs->pending.objects = NULL;
 987         while (--nr >= 0) {
 988                 struct commit *commit = handle_commit(revs, list->item, list->name);
 989                 if (commit) {
 990                         if (!(commit->object.flags & SEEN)) {
 991                                 commit->object.flags |= SEEN;
 992                                 insert_by_date(commit, &revs->commits);
 993                         }
 994                 }
 995                 list++;
 996         }
 997
 998         if (revs->no_walk)
 999                 return;
1000         if (revs->limited)
1001                 limit_list(revs);
1002         if (revs->topo_order)
1003                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
1004                                              revs->topo_setter,
1005                                              revs->topo_getter);
1006 }
1007
1008 static int rewrite_one(struct rev_info *revs, struct commit **pp)
1009 {
1010         for (;;) {
1011                 struct commit *p = *pp;
1012                 if (!revs->limited)
1013                         add_parents_to_list(revs, p, &revs->commits);
1014                 if (p->parents && p->parents->next)
1015                         return 0;
1016                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
1017                         return 0;
1018                 if (!p->parents)
1019                         return -1;
1020                 *pp = p->parents->item;
1021         }
1022 }
1023
1024 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
1025 {
1026         struct commit_list **pp = &commit->parents;
1027         while (*pp) {
1028                 struct commit_list *parent = *pp;
1029                 if (rewrite_one(revs, &parent->item) < 0) {
1030                         *pp = parent->next;
1031                         continue;
1032                 }
1033                 pp = &parent->next;
1034         }
1035 }
1036
1037 static void mark_boundary_to_show(struct commit *commit)
1038 {
1039         struct commit_list *p = commit->parents;
1040         while (p) {
1041                 commit = p->item;
1042                 p = p->next;
1043                 if (commit->object.flags & BOUNDARY)
1044                         commit->object.flags |= BOUNDARY_SHOW;
1045         }
1046 }
1047
1048 struct commit *get_revision(struct rev_info *revs)
1049 {
1050         struct commit_list *list = revs->commits;
1051
1052         if (!list)
1053                 return NULL;
1054
1055         /* Check the max_count ... */
1056         switch (revs->max_count) {
1057         case -1:
1058                 break;
1059         case 0:
1060                 return NULL;
1061         default:
1062                 revs->max_count--;
1063         }
1064
1065         do {
1066                 struct commit_list *entry = revs->commits;
1067                 struct commit *commit = entry->item;
1068
1069                 revs->commits = entry->next;
1070                 free(entry);
1071
1072                 /*
1073                  * If we haven't done the list limiting, we need to look at
1074                  * the parents here. We also need to do the date-based limiting
1075                  * that we'd otherwise have done in limit_list().
1076                  */
1077                 if (!revs->limited) {
1078                         if ((revs->unpacked &&
1079                              has_sha1_pack(commit->object.sha1,
1080                                            revs->ignore_packed)) ||
1081                             (revs->max_age != -1 &&
1082                              (commit->date < revs->max_age)))
1083                                 continue;
1084                         add_parents_to_list(revs, commit, &revs->commits);
1085                 }
1086                 if (commit->object.flags & SHOWN)
1087                         continue;
1088
1089                 /* We want to show boundary commits only when their
1090                  * children are shown.  When path-limiter is in effect,
1091                  * rewrite_parents() drops some commits from getting shown,
1092                  * and there is no point showing boundary parents that
1093                  * are not shown.  After rewrite_parents() rewrites the
1094                  * parents of a commit that is shown, we mark the boundary
1095                  * parents with BOUNDARY_SHOW.
1096                  */
1097                 if (commit->object.flags & BOUNDARY_SHOW) {
1098                         commit->object.flags |= SHOWN;
1099                         return commit;
1100                 }
1101                 if (commit->object.flags & UNINTERESTING)
1102                         continue;
1103                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1104                         continue;
1105                 if (revs->no_merges &&
1106                     commit->parents && commit->parents->next)
1107                         continue;
1108                 if (revs->prune_fn && revs->dense) {
1109                         /* Commit without changes? */
1110                         if (!(commit->object.flags & TREECHANGE)) {
1111                                 /* drop merges unless we want parenthood */
1112                                 if (!revs->parents)
1113                                         continue;
1114                                 /* non-merge - always ignore it */
1115                                 if (!commit->parents || !commit->parents->next)
1116                                         continue;
1117                         }
1118                         if (revs->parents)
1119                                 rewrite_parents(revs, commit);
1120                 }
1121                 if (revs->boundary)
1122                         mark_boundary_to_show(commit);
1123                 commit->object.flags |= SHOWN;
1124                 return commit;
1125         } while (revs->commits);
1126         return NULL;
1127 }