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 && has_sha1_pack(obj->sha1))
 420                         obj->flags |= UNINTERESTING;
 421                 add_parents_to_list(revs, commit, &list);
 422                 if (obj->flags & UNINTERESTING) {
 423                         mark_parents_uninteresting(commit);
 424                         if (everybody_uninteresting(list))
 425                                 break;
 426                         continue;
 427                 }
 428                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 429                         continue;
 430                 p = &commit_list_insert(commit, p)->next;
 431         }
 432         if (revs->boundary) {
 433                 /* mark the ones that are on the result list first */
 434                 for (list = newlist; list; list = list->next) {
 435                         struct commit *commit = list->item;
 436                         commit->object.flags |= TMP_MARK;
 437                 }
 438                 for (list = newlist; list; list = list->next) {
 439                         struct commit *commit = list->item;
 440                         struct object *obj = &commit->object;
 441                         struct commit_list *parent;
 442                         if (obj->flags & UNINTERESTING)
 443                                 continue;
 444                         for (parent = commit->parents;
 445                              parent;
 446                              parent = parent->next) {
 447                                 struct commit *pcommit = parent->item;
 448                                 if (!(pcommit->object.flags & UNINTERESTING))
 449                                         continue;
 450                                 pcommit->object.flags |= BOUNDARY;
 451                                 if (pcommit->object.flags & TMP_MARK)
 452                                         continue;
 453                                 pcommit->object.flags |= TMP_MARK;
 454                                 p = &commit_list_insert(pcommit, p)->next;
 455                         }
 456                 }
 457                 for (list = newlist; list; list = list->next) {
 458                         struct commit *commit = list->item;
 459                         commit->object.flags &= ~TMP_MARK;
 460                 }
 461         }
 462         revs->commits = newlist;
 463 }
 464
 465 static int all_flags;
 466 static struct rev_info *all_revs;
 467
 468 static int handle_one_ref(const char *path, const unsigned char *sha1)
 469 {
 470         struct object *object = get_reference(all_revs, path, sha1, all_flags);
 471         add_pending_object(all_revs, object, "");
 472         return 0;
 473 }
 474
 475 static void handle_all(struct rev_info *revs, unsigned flags)
 476 {
 477         all_revs = revs;
 478         all_flags = flags;
 479         for_each_ref(handle_one_ref);
 480 }
 481
 482 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 483 {
 484         unsigned char sha1[20];
 485         struct object *it;
 486         struct commit *commit;
 487         struct commit_list *parents;
 488
 489         if (*arg == '^') {
 490                 flags ^= UNINTERESTING;
 491                 arg++;
 492         }
 493         if (get_sha1(arg, sha1))
 494                 return 0;
 495         while (1) {
 496                 it = get_reference(revs, arg, sha1, 0);
 497                 if (it->type != OBJ_TAG)
 498                         break;
 499                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 500         }
 501         if (it->type != OBJ_COMMIT)
 502                 return 0;
 503         commit = (struct commit *)it;
 504         for (parents = commit->parents; parents; parents = parents->next) {
 505                 it = &parents->item->object;
 506                 it->flags |= flags;
 507                 add_pending_object(revs, it, arg);
 508         }
 509         return 1;
 510 }
 511
 512 void init_revisions(struct rev_info *revs, const char *prefix)
 513 {
 514         memset(revs, 0, sizeof(*revs));
 515
 516         revs->abbrev = DEFAULT_ABBREV;
 517         revs->ignore_merges = 1;
 518         revs->simplify_history = 1;
 519         revs->pruning.recursive = 1;
 520         revs->pruning.add_remove = file_add_remove;
 521         revs->pruning.change = file_change;
 522         revs->lifo = 1;
 523         revs->dense = 1;
 524         revs->prefix = prefix;
 525         revs->max_age = -1;
 526         revs->min_age = -1;
 527         revs->max_count = -1;
 528
 529         revs->prune_fn = NULL;
 530         revs->prune_data = NULL;
 531
 532         revs->topo_setter = topo_sort_default_setter;
 533         revs->topo_getter = topo_sort_default_getter;
 534
 535         revs->commit_format = CMIT_FMT_DEFAULT;
 536
 537         diff_setup(&revs->diffopt);
 538 }
 539
 540 static void add_pending_commit_list(struct rev_info *revs,
 541                                     struct commit_list *commit_list,
 542                                     unsigned int flags)
 543 {
 544         while (commit_list) {
 545                 struct object *object = &commit_list->item->object;
 546                 object->flags |= flags;
 547                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 548                 commit_list = commit_list->next;
 549         }
 550 }
 551
 552 static void prepare_show_merge(struct rev_info *revs)
 553 {
 554         struct commit_list *bases;
 555         struct commit *head, *other;
 556         unsigned char sha1[20];
 557         const char **prune = NULL;
 558         int i, prune_num = 1; /* counting terminating NULL */
 559
 560         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 561                 die("--merge without HEAD?");
 562         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 563                 die("--merge without MERGE_HEAD?");
 564         add_pending_object(revs, &head->object, "HEAD");
 565         add_pending_object(revs, &other->object, "MERGE_HEAD");
 566         bases = get_merge_bases(head, other, 1);
 567         while (bases) {
 568                 struct commit *it = bases->item;
 569                 struct commit_list *n = bases->next;
 570                 free(bases);
 571                 bases = n;
 572                 it->object.flags |= UNINTERESTING;
 573                 add_pending_object(revs, &it->object, "(merge-base)");
 574         }
 575
 576         if (!active_nr)
 577                 read_cache();
 578         for (i = 0; i < active_nr; i++) {
 579                 struct cache_entry *ce = active_cache[i];
 580                 if (!ce_stage(ce))
 581                         continue;
 582                 if (ce_path_match(ce, revs->prune_data)) {
 583                         prune_num++;
 584                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 585                         prune[prune_num-2] = ce->name;
 586                         prune[prune_num-1] = NULL;
 587                 }
 588                 while ((i+1 < active_nr) &&
 589                        ce_same_name(ce, active_cache[i+1]))
 590                         i++;
 591         }
 592         revs->prune_data = prune;
 593 }
 594
 595 /*
 596  * Parse revision information, filling in the "rev_info" structure,
 597  * and removing the used arguments from the argument list.
 598  *
 599  * Returns the number of arguments left that weren't recognized
 600  * (which are also moved to the head of the argument list)
 601  */
 602 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 603 {
 604         int i, flags, seen_dashdash, show_merge;
 605         const char **unrecognized = argv + 1;
 606         int left = 1;
 607
 608         /* First, search for "--" */
 609         seen_dashdash = 0;
 610         for (i = 1; i < argc; i++) {
 611                 const char *arg = argv[i];
 612                 if (strcmp(arg, "--"))
 613                         continue;
 614                 argv[i] = NULL;
 615                 argc = i;
 616                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 617                 seen_dashdash = 1;
 618                 break;
 619         }
 620
 621         flags = show_merge = 0;
 622         for (i = 1; i < argc; i++) {
 623                 struct object *object;
 624                 const char *arg = argv[i];
 625                 unsigned char sha1[20];
 626                 char *dotdot;
 627                 int local_flags;
 628
 629                 if (*arg == '-') {
 630                         int opts;
 631                         if (!strncmp(arg, "--max-count=", 12)) {
 632                                 revs->max_count = atoi(arg + 12);
 633                                 continue;
 634                         }
 635                         /* accept -<digit>, like traditional "head" */
 636                         if ((*arg == '-') && isdigit(arg[1])) {
 637                                 revs->max_count = atoi(arg + 1);
 638                                 continue;
 639                         }
 640                         if (!strcmp(arg, "-n")) {
 641                                 if (argc <= i + 1)
 642                                         die("-n requires an argument");
 643                                 revs->max_count = atoi(argv[++i]);
 644                                 continue;
 645                         }
 646                         if (!strncmp(arg,"-n",2)) {
 647                                 revs->max_count = atoi(arg + 2);
 648                                 continue;
 649                         }
 650                         if (!strncmp(arg, "--max-age=", 10)) {
 651                                 revs->max_age = atoi(arg + 10);
 652                                 continue;
 653                         }
 654                         if (!strncmp(arg, "--since=", 8)) {
 655                                 revs->max_age = approxidate(arg + 8);
 656                                 continue;
 657                         }
 658                         if (!strncmp(arg, "--after=", 8)) {
 659                                 revs->max_age = approxidate(arg + 8);
 660                                 continue;
 661                         }
 662                         if (!strncmp(arg, "--min-age=", 10)) {
 663                                 revs->min_age = atoi(arg + 10);
 664                                 continue;
 665                         }
 666                         if (!strncmp(arg, "--before=", 9)) {
 667                                 revs->min_age = approxidate(arg + 9);
 668                                 continue;
 669                         }
 670                         if (!strncmp(arg, "--until=", 8)) {
 671                                 revs->min_age = approxidate(arg + 8);
 672                                 continue;
 673                         }
 674                         if (!strcmp(arg, "--all")) {
 675                                 handle_all(revs, flags);
 676                                 continue;
 677                         }
 678                         if (!strcmp(arg, "--not")) {
 679                                 flags ^= UNINTERESTING;
 680                                 continue;
 681                         }
 682                         if (!strcmp(arg, "--default")) {
 683                                 if (++i >= argc)
 684                                         die("bad --default argument");
 685                                 def = argv[i];
 686                                 continue;
 687                         }
 688                         if (!strcmp(arg, "--merge")) {
 689                                 show_merge = 1;
 690                                 continue;
 691                         }
 692                         if (!strcmp(arg, "--topo-order")) {
 693                                 revs->topo_order = 1;
 694                                 continue;
 695                         }
 696                         if (!strcmp(arg, "--date-order")) {
 697                                 revs->lifo = 0;
 698                                 revs->topo_order = 1;
 699                                 continue;
 700                         }
 701                         if (!strcmp(arg, "--parents")) {
 702                                 revs->parents = 1;
 703                                 continue;
 704                         }
 705                         if (!strcmp(arg, "--dense")) {
 706                                 revs->dense = 1;
 707                                 continue;
 708                         }
 709                         if (!strcmp(arg, "--sparse")) {
 710                                 revs->dense = 0;
 711                                 continue;
 712                         }
 713                         if (!strcmp(arg, "--remove-empty")) {
 714                                 revs->remove_empty_trees = 1;
 715                                 continue;
 716                         }
 717                         if (!strcmp(arg, "--no-merges")) {
 718                                 revs->no_merges = 1;
 719                                 continue;
 720                         }
 721                         if (!strcmp(arg, "--boundary")) {
 722                                 revs->boundary = 1;
 723                                 continue;
 724                         }
 725                         if (!strcmp(arg, "--objects")) {
 726                                 revs->tag_objects = 1;
 727                                 revs->tree_objects = 1;
 728                                 revs->blob_objects = 1;
 729                                 continue;
 730                         }
 731                         if (!strcmp(arg, "--objects-edge")) {
 732                                 revs->tag_objects = 1;
 733                                 revs->tree_objects = 1;
 734                                 revs->blob_objects = 1;
 735                                 revs->edge_hint = 1;
 736                                 continue;
 737                         }
 738                         if (!strcmp(arg, "--unpacked")) {
 739                                 revs->unpacked = 1;
 740                                 continue;
 741                         }
 742                         if (!strcmp(arg, "-r")) {
 743                                 revs->diff = 1;
 744                                 revs->diffopt.recursive = 1;
 745                                 continue;
 746                         }
 747                         if (!strcmp(arg, "-t")) {
 748                                 revs->diff = 1;
 749                                 revs->diffopt.recursive = 1;
 750                                 revs->diffopt.tree_in_recursive = 1;
 751                                 continue;
 752                         }
 753                         if (!strcmp(arg, "-m")) {
 754                                 revs->ignore_merges = 0;
 755                                 continue;
 756                         }
 757                         if (!strcmp(arg, "-c")) {
 758                                 revs->diff = 1;
 759                                 revs->dense_combined_merges = 0;
 760                                 revs->combine_merges = 1;
 761                                 continue;
 762                         }
 763                         if (!strcmp(arg, "--cc")) {
 764                                 revs->diff = 1;
 765                                 revs->dense_combined_merges = 1;
 766                                 revs->combine_merges = 1;
 767                                 continue;
 768                         }
 769                         if (!strcmp(arg, "-v")) {
 770                                 revs->verbose_header = 1;
 771                                 continue;
 772                         }
 773                         if (!strncmp(arg, "--pretty", 8)) {
 774                                 revs->verbose_header = 1;
 775                                 revs->commit_format = get_commit_format(arg+8);
 776                                 continue;
 777                         }
 778                         if (!strcmp(arg, "--root")) {
 779                                 revs->show_root_diff = 1;
 780                                 continue;
 781                         }
 782                         if (!strcmp(arg, "--no-commit-id")) {
 783                                 revs->no_commit_id = 1;
 784                                 continue;
 785                         }
 786                         if (!strcmp(arg, "--always")) {
 787                                 revs->always_show_header = 1;
 788                                 continue;
 789                         }
 790                         if (!strcmp(arg, "--no-abbrev")) {
 791                                 revs->abbrev = 0;
 792                                 continue;
 793                         }
 794                         if (!strcmp(arg, "--abbrev")) {
 795                                 revs->abbrev = DEFAULT_ABBREV;
 796                                 continue;
 797                         }
 798                         if (!strncmp(arg, "--abbrev=", 9)) {
 799                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
 800                                 if (revs->abbrev < MINIMUM_ABBREV)
 801                                         revs->abbrev = MINIMUM_ABBREV;
 802                                 else if (revs->abbrev > 40)
 803                                         revs->abbrev = 40;
 804                                 continue;
 805                         }
 806                         if (!strcmp(arg, "--abbrev-commit")) {
 807                                 revs->abbrev_commit = 1;
 808                                 continue;
 809                         }
 810                         if (!strcmp(arg, "--full-diff")) {
 811                                 revs->diff = 1;
 812                                 revs->full_diff = 1;
 813                                 continue;
 814                         }
 815                         if (!strcmp(arg, "--full-history")) {
 816                                 revs->simplify_history = 0;
 817                                 continue;
 818                         }
 819                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
 820                         if (opts > 0) {
 821                                 revs->diff = 1;
 822                                 i += opts - 1;
 823                                 continue;
 824                         }
 825                         *unrecognized++ = arg;
 826                         left++;
 827                         continue;
 828                 }
 829                 dotdot = strstr(arg, "..");
 830                 if (dotdot) {
 831                         unsigned char from_sha1[20];
 832                         const char *next = dotdot + 2;
 833                         const char *this = arg;
 834                         int symmetric = *next == '.';
 835                         unsigned int flags_exclude = flags ^ UNINTERESTING;
 836
 837                         *dotdot = 0;
 838                         next += symmetric;
 839
 840                         if (!*next)
 841                                 next = "HEAD";
 842                         if (dotdot == arg)
 843                                 this = "HEAD";
 844                         if (!get_sha1(this, from_sha1) &&
 845                             !get_sha1(next, sha1)) {
 846                                 struct commit *a, *b;
 847                                 struct commit_list *exclude;
 848
 849                                 a = lookup_commit_reference(from_sha1);
 850                                 b = lookup_commit_reference(sha1);
 851                                 if (!a || !b) {
 852                                         die(symmetric ?
 853                                             "Invalid symmetric difference expression %s...%s" :
 854                                             "Invalid revision range %s..%s",
 855                                             arg, next);
 856                                 }
 857
 858                                 if (!seen_dashdash) {
 859                                         *dotdot = '.';
 860                                         verify_non_filename(revs->prefix, arg);
 861                                 }
 862
 863                                 if (symmetric) {
 864                                         exclude = get_merge_bases(a, b, 1);
 865                                         add_pending_commit_list(revs, exclude,
 866                                                                 flags_exclude);
 867                                         free_commit_list(exclude);
 868                                         a->object.flags |= flags;
 869                                 } else
 870                                         a->object.flags |= flags_exclude;
 871                                 b->object.flags |= flags;
 872                                 add_pending_object(revs, &a->object, this);
 873                                 add_pending_object(revs, &b->object, next);
 874                                 continue;
 875                         }
 876                         *dotdot = '.';
 877                 }
 878                 dotdot = strstr(arg, "^@");
 879                 if (dotdot && !dotdot[2]) {
 880                         *dotdot = 0;
 881                         if (add_parents_only(revs, arg, flags))
 882                                 continue;
 883                         *dotdot = '^';
 884                 }
 885                 local_flags = 0;
 886                 if (*arg == '^') {
 887                         local_flags = UNINTERESTING;
 888                         arg++;
 889                 }
 890                 if (get_sha1(arg, sha1)) {
 891                         int j;
 892
 893                         if (seen_dashdash || local_flags)
 894                                 die("bad revision '%s'", arg);
 895
 896                         /* If we didn't have a "--":
 897                          * (1) all filenames must exist;
 898                          * (2) all rev-args must not be interpretable
 899                          *     as a valid filename.
 900                          * but the latter we have checked in the main loop.
 901                          */
 902                         for (j = i; j < argc; j++)
 903                                 verify_filename(revs->prefix, argv[j]);
 904
 905                         revs->prune_data = get_pathspec(revs->prefix, argv + i);
 906                         break;
 907                 }
 908                 if (!seen_dashdash)
 909                         verify_non_filename(revs->prefix, arg);
 910                 object = get_reference(revs, arg, sha1, flags ^ local_flags);
 911                 add_pending_object(revs, object, arg);
 912         }
 913         if (show_merge)
 914                 prepare_show_merge(revs);
 915         if (def && !revs->pending.nr) {
 916                 unsigned char sha1[20];
 917                 struct object *object;
 918                 if (get_sha1(def, sha1))
 919                         die("bad default revision '%s'", def);
 920                 object = get_reference(revs, def, sha1, 0);
 921                 add_pending_object(revs, object, def);
 922         }
 923
 924         if (revs->topo_order || revs->unpacked)
 925                 revs->limited = 1;
 926
 927         if (revs->prune_data) {
 928                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
 929                 revs->prune_fn = try_to_simplify_commit;
 930                 if (!revs->full_diff)
 931                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
 932         }
 933         if (revs->combine_merges) {
 934                 revs->ignore_merges = 0;
 935                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
 936                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 937         }
 938         revs->diffopt.abbrev = revs->abbrev;
 939         if (diff_setup_done(&revs->diffopt) < 0)
 940                 die("diff_setup_done failed");
 941
 942         return left;
 943 }
 944
 945 void prepare_revision_walk(struct rev_info *revs)
 946 {
 947         int nr = revs->pending.nr;
 948         struct object_array_entry *list = revs->pending.objects;
 949
 950         revs->pending.nr = 0;
 951         revs->pending.alloc = 0;
 952         revs->pending.objects = NULL;
 953         while (--nr >= 0) {
 954                 struct commit *commit = handle_commit(revs, list->item, list->name);
 955                 if (commit) {
 956                         if (!(commit->object.flags & SEEN)) {
 957                                 commit->object.flags |= SEEN;
 958                                 insert_by_date(commit, &revs->commits);
 959                         }
 960                 }
 961                 list++;
 962         }
 963
 964         if (revs->no_walk)
 965                 return;
 966         if (revs->limited)
 967                 limit_list(revs);
 968         if (revs->topo_order)
 969                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
 970                                              revs->topo_setter,
 971                                              revs->topo_getter);
 972 }
 973
 974 static int rewrite_one(struct rev_info *revs, struct commit **pp)
 975 {
 976         for (;;) {
 977                 struct commit *p = *pp;
 978                 if (!revs->limited)
 979                         add_parents_to_list(revs, p, &revs->commits);
 980                 if (p->parents && p->parents->next)
 981                         return 0;
 982                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
 983                         return 0;
 984                 if (!p->parents)
 985                         return -1;
 986                 *pp = p->parents->item;
 987         }
 988 }
 989
 990 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
 991 {
 992         struct commit_list **pp = &commit->parents;
 993         while (*pp) {
 994                 struct commit_list *parent = *pp;
 995                 if (rewrite_one(revs, &parent->item) < 0) {
 996                         *pp = parent->next;
 997                         continue;
 998                 }
 999                 pp = &parent->next;
1000         }
1001 }
1002
1003 static void mark_boundary_to_show(struct commit *commit)
1004 {
1005         struct commit_list *p = commit->parents;
1006         while (p) {
1007                 commit = p->item;
1008                 p = p->next;
1009                 if (commit->object.flags & BOUNDARY)
1010                         commit->object.flags |= BOUNDARY_SHOW;
1011         }
1012 }
1013
1014 struct commit *get_revision(struct rev_info *revs)
1015 {
1016         struct commit_list *list = revs->commits;
1017
1018         if (!list)
1019                 return NULL;
1020
1021         /* Check the max_count ... */
1022         switch (revs->max_count) {
1023         case -1:
1024                 break;
1025         case 0:
1026                 return NULL;
1027         default:
1028                 revs->max_count--;
1029         }
1030
1031         do {
1032                 struct commit_list *entry = revs->commits;
1033                 struct commit *commit = entry->item;
1034
1035                 revs->commits = entry->next;
1036                 free(entry);
1037
1038                 /*
1039                  * If we haven't done the list limiting, we need to look at
1040                  * the parents here. We also need to do the date-based limiting
1041                  * that we'd otherwise have done in limit_list().
1042                  */
1043                 if (!revs->limited) {
1044                         if ((revs->unpacked &&
1045                              has_sha1_pack(commit->object.sha1)) ||
1046                             (revs->max_age != -1 &&
1047                              (commit->date < revs->max_age)))
1048                                 continue;
1049                         add_parents_to_list(revs, commit, &revs->commits);
1050                 }
1051                 if (commit->object.flags & SHOWN)
1052                         continue;
1053
1054                 /* We want to show boundary commits only when their
1055                  * children are shown.  When path-limiter is in effect,
1056                  * rewrite_parents() drops some commits from getting shown,
1057                  * and there is no point showing boundary parents that
1058                  * are not shown.  After rewrite_parents() rewrites the
1059                  * parents of a commit that is shown, we mark the boundary
1060                  * parents with BOUNDARY_SHOW.
1061                  */
1062                 if (commit->object.flags & BOUNDARY_SHOW) {
1063                         commit->object.flags |= SHOWN;
1064                         return commit;
1065                 }
1066                 if (commit->object.flags & UNINTERESTING)
1067                         continue;
1068                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1069                         continue;
1070                 if (revs->no_merges &&
1071                     commit->parents && commit->parents->next)
1072                         continue;
1073                 if (revs->prune_fn && revs->dense) {
1074                         /* Commit without changes? */
1075                         if (!(commit->object.flags & TREECHANGE)) {
1076                                 /* drop merges unless we want parenthood */
1077                                 if (!revs->parents)
1078                                         continue;
1079                                 /* non-merge - always ignore it */
1080                                 if (!commit->parents || !commit->parents->next)
1081                                         continue;
1082                         }
1083                         if (revs->parents)
1084                                 rewrite_parents(revs, commit);
1085                 }
1086                 if (revs->boundary)
1087                         mark_boundary_to_show(commit);
1088                 commit->object.flags |= SHOWN;
1089                 return commit;
1090         } while (revs->commits);
1091         return NULL;
1092 }