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 == TYPE_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 == TYPE_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 == TYPE_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 == TYPE_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;
 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                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 302                                 /* Even if a merge with an uninteresting
 303                                  * side branch brought the entire change
 304                                  * we are interested in, we do not want
 305                                  * to lose the other branches of this
 306                                  * merge, so we just keep going.
 307                                  */
 308                                 pp = &parent->next;
 309                                 continue;
 310                         }
 311                         parent->next = NULL;
 312                         commit->parents = parent;
 313                         return;
 314
 315                 case REV_TREE_NEW:
 316                         if (revs->remove_empty_trees &&
 317                             rev_same_tree_as_empty(revs, p->tree)) {
 318                                 /* We are adding all the specified
 319                                  * paths from this parent, so the
 320                                  * history beyond this parent is not
 321                                  * interesting.  Remove its parents
 322                                  * (they are grandparents for us).
 323                                  * IOW, we pretend this parent is a
 324                                  * "root" commit.
 325                                  */
 326                                 parse_commit(p);
 327                                 p->parents = NULL;
 328                         }
 329                 /* fallthrough */
 330                 case REV_TREE_DIFFERENT:
 331                         tree_changed = 1;
 332                         pp = &parent->next;
 333                         continue;
 334                 }
 335                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 336         }
 337         if (tree_changed)
 338                 commit->object.flags |= TREECHANGE;
 339 }
 340
 341 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 342 {
 343         struct commit_list *parent = commit->parents;
 344
 345         if (commit->object.flags & ADDED)
 346                 return;
 347         commit->object.flags |= ADDED;
 348
 349         /*
 350          * If the commit is uninteresting, don't try to
 351          * prune parents - we want the maximal uninteresting
 352          * set.
 353          *
 354          * Normally we haven't parsed the parent
 355          * yet, so we won't have a parent of a parent
 356          * here. However, it may turn out that we've
 357          * reached this commit some other way (where it
 358          * wasn't uninteresting), in which case we need
 359          * to mark its parents recursively too..
 360          */
 361         if (commit->object.flags & UNINTERESTING) {
 362                 while (parent) {
 363                         struct commit *p = parent->item;
 364                         parent = parent->next;
 365                         parse_commit(p);
 366                         p->object.flags |= UNINTERESTING;
 367                         if (p->parents)
 368                                 mark_parents_uninteresting(p);
 369                         if (p->object.flags & SEEN)
 370                                 continue;
 371                         p->object.flags |= SEEN;
 372                         insert_by_date(p, list);
 373                 }
 374                 return;
 375         }
 376
 377         /*
 378          * Ok, the commit wasn't uninteresting. Try to
 379          * simplify the commit history and find the parent
 380          * that has no differences in the path set if one exists.
 381          */
 382         if (revs->prune_fn)
 383                 revs->prune_fn(revs, commit);
 384
 385         if (revs->no_walk)
 386                 return;
 387
 388         parent = commit->parents;
 389         while (parent) {
 390                 struct commit *p = parent->item;
 391
 392                 parent = parent->next;
 393
 394                 parse_commit(p);
 395                 if (p->object.flags & SEEN)
 396                         continue;
 397                 p->object.flags |= SEEN;
 398                 insert_by_date(p, list);
 399         }
 400 }
 401
 402 static void limit_list(struct rev_info *revs)
 403 {
 404         struct commit_list *list = revs->commits;
 405         struct commit_list *newlist = NULL;
 406         struct commit_list **p = &newlist;
 407
 408         while (list) {
 409                 struct commit_list *entry = list;
 410                 struct commit *commit = list->item;
 411                 struct object *obj = &commit->object;
 412
 413                 list = list->next;
 414                 free(entry);
 415
 416                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 417                         obj->flags |= UNINTERESTING;
 418                 if (revs->unpacked && has_sha1_pack(obj->sha1))
 419                         obj->flags |= UNINTERESTING;
 420                 add_parents_to_list(revs, commit, &list);
 421                 if (obj->flags & UNINTERESTING) {
 422                         mark_parents_uninteresting(commit);
 423                         if (everybody_uninteresting(list))
 424                                 break;
 425                         continue;
 426                 }
 427                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 428                         continue;
 429                 p = &commit_list_insert(commit, p)->next;
 430         }
 431         if (revs->boundary) {
 432                 /* mark the ones that are on the result list first */
 433                 for (list = newlist; list; list = list->next) {
 434                         struct commit *commit = list->item;
 435                         commit->object.flags |= TMP_MARK;
 436                 }
 437                 for (list = newlist; list; list = list->next) {
 438                         struct commit *commit = list->item;
 439                         struct object *obj = &commit->object;
 440                         struct commit_list *parent;
 441                         if (obj->flags & UNINTERESTING)
 442                                 continue;
 443                         for (parent = commit->parents;
 444                              parent;
 445                              parent = parent->next) {
 446                                 struct commit *pcommit = parent->item;
 447                                 if (!(pcommit->object.flags & UNINTERESTING))
 448                                         continue;
 449                                 pcommit->object.flags |= BOUNDARY;
 450                                 if (pcommit->object.flags & TMP_MARK)
 451                                         continue;
 452                                 pcommit->object.flags |= TMP_MARK;
 453                                 p = &commit_list_insert(pcommit, p)->next;
 454                         }
 455                 }
 456                 for (list = newlist; list; list = list->next) {
 457                         struct commit *commit = list->item;
 458                         commit->object.flags &= ~TMP_MARK;
 459                 }
 460         }
 461         revs->commits = newlist;
 462 }
 463
 464 static int all_flags;
 465 static struct rev_info *all_revs;
 466
 467 static int handle_one_ref(const char *path, const unsigned char *sha1)
 468 {
 469         struct object *object = get_reference(all_revs, path, sha1, all_flags);
 470         add_pending_object(all_revs, object, "");
 471         return 0;
 472 }
 473
 474 static void handle_all(struct rev_info *revs, unsigned flags)
 475 {
 476         all_revs = revs;
 477         all_flags = flags;
 478         for_each_ref(handle_one_ref);
 479 }
 480
 481 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 482 {
 483         unsigned char sha1[20];
 484         struct object *it;
 485         struct commit *commit;
 486         struct commit_list *parents;
 487
 488         if (*arg == '^') {
 489                 flags ^= UNINTERESTING;
 490                 arg++;
 491         }
 492         if (get_sha1(arg, sha1))
 493                 return 0;
 494         while (1) {
 495                 it = get_reference(revs, arg, sha1, 0);
 496                 if (it->type != TYPE_TAG)
 497                         break;
 498                 memcpy(sha1, ((struct tag*)it)->tagged->sha1, 20);
 499         }
 500         if (it->type != TYPE_COMMIT)
 501                 return 0;
 502         commit = (struct commit *)it;
 503         for (parents = commit->parents; parents; parents = parents->next) {
 504                 it = &parents->item->object;
 505                 it->flags |= flags;
 506                 add_pending_object(revs, it, arg);
 507         }
 508         return 1;
 509 }
 510
 511 void init_revisions(struct rev_info *revs)
 512 {
 513         memset(revs, 0, sizeof(*revs));
 514
 515         revs->abbrev = DEFAULT_ABBREV;
 516         revs->ignore_merges = 1;
 517         revs->simplify_history = 1;
 518         revs->pruning.recursive = 1;
 519         revs->pruning.add_remove = file_add_remove;
 520         revs->pruning.change = file_change;
 521         revs->lifo = 1;
 522         revs->dense = 1;
 523         revs->prefix = setup_git_directory();
 524         revs->max_age = -1;
 525         revs->min_age = -1;
 526         revs->max_count = -1;
 527
 528         revs->prune_fn = NULL;
 529         revs->prune_data = NULL;
 530
 531         revs->topo_setter = topo_sort_default_setter;
 532         revs->topo_getter = topo_sort_default_getter;
 533
 534         revs->commit_format = CMIT_FMT_DEFAULT;
 535
 536         diff_setup(&revs->diffopt);
 537 }
 538
 539 /*
 540  * Parse revision information, filling in the "rev_info" structure,
 541  * and removing the used arguments from the argument list.
 542  *
 543  * Returns the number of arguments left that weren't recognized
 544  * (which are also moved to the head of the argument list)
 545  */
 546 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 547 {
 548         int i, flags, seen_dashdash;
 549         const char **unrecognized = argv + 1;
 550         int left = 1;
 551
 552         /* First, search for "--" */
 553         seen_dashdash = 0;
 554         for (i = 1; i < argc; i++) {
 555                 const char *arg = argv[i];
 556                 if (strcmp(arg, "--"))
 557                         continue;
 558                 argv[i] = NULL;
 559                 argc = i;
 560                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 561                 seen_dashdash = 1;
 562                 break;
 563         }
 564
 565         flags = 0;
 566         for (i = 1; i < argc; i++) {
 567                 struct object *object;
 568                 const char *arg = argv[i];
 569                 unsigned char sha1[20];
 570                 char *dotdot;
 571                 int local_flags;
 572
 573                 if (*arg == '-') {
 574                         int opts;
 575                         if (!strncmp(arg, "--max-count=", 12)) {
 576                                 revs->max_count = atoi(arg + 12);
 577                                 continue;
 578                         }
 579                         /* accept -<digit>, like traditional "head" */
 580                         if ((*arg == '-') && isdigit(arg[1])) {
 581                                 revs->max_count = atoi(arg + 1);
 582                                 continue;
 583                         }
 584                         if (!strcmp(arg, "-n")) {
 585                                 if (argc <= i + 1)
 586                                         die("-n requires an argument");
 587                                 revs->max_count = atoi(argv[++i]);
 588                                 continue;
 589                         }
 590                         if (!strncmp(arg,"-n",2)) {
 591                                 revs->max_count = atoi(arg + 2);
 592                                 continue;
 593                         }
 594                         if (!strncmp(arg, "--max-age=", 10)) {
 595                                 revs->max_age = atoi(arg + 10);
 596                                 continue;
 597                         }
 598                         if (!strncmp(arg, "--since=", 8)) {
 599                                 revs->max_age = approxidate(arg + 8);
 600                                 continue;
 601                         }
 602                         if (!strncmp(arg, "--after=", 8)) {
 603                                 revs->max_age = approxidate(arg + 8);
 604                                 continue;
 605                         }
 606                         if (!strncmp(arg, "--min-age=", 10)) {
 607                                 revs->min_age = atoi(arg + 10);
 608                                 continue;
 609                         }
 610                         if (!strncmp(arg, "--before=", 9)) {
 611                                 revs->min_age = approxidate(arg + 9);
 612                                 continue;
 613                         }
 614                         if (!strncmp(arg, "--until=", 8)) {
 615                                 revs->min_age = approxidate(arg + 8);
 616                                 continue;
 617                         }
 618                         if (!strcmp(arg, "--all")) {
 619                                 handle_all(revs, flags);
 620                                 continue;
 621                         }
 622                         if (!strcmp(arg, "--not")) {
 623                                 flags ^= UNINTERESTING;
 624                                 continue;
 625                         }
 626                         if (!strcmp(arg, "--default")) {
 627                                 if (++i >= argc)
 628                                         die("bad --default argument");
 629                                 def = argv[i];
 630                                 continue;
 631                         }
 632                         if (!strcmp(arg, "--topo-order")) {
 633                                 revs->topo_order = 1;
 634                                 continue;
 635                         }
 636                         if (!strcmp(arg, "--date-order")) {
 637                                 revs->lifo = 0;
 638                                 revs->topo_order = 1;
 639                                 continue;
 640                         }
 641                         if (!strcmp(arg, "--parents")) {
 642                                 revs->parents = 1;
 643                                 continue;
 644                         }
 645                         if (!strcmp(arg, "--dense")) {
 646                                 revs->dense = 1;
 647                                 continue;
 648                         }
 649                         if (!strcmp(arg, "--sparse")) {
 650                                 revs->dense = 0;
 651                                 continue;
 652                         }
 653                         if (!strcmp(arg, "--remove-empty")) {
 654                                 revs->remove_empty_trees = 1;
 655                                 continue;
 656                         }
 657                         if (!strcmp(arg, "--no-merges")) {
 658                                 revs->no_merges = 1;
 659                                 continue;
 660                         }
 661                         if (!strcmp(arg, "--boundary")) {
 662                                 revs->boundary = 1;
 663                                 continue;
 664                         }
 665                         if (!strcmp(arg, "--objects")) {
 666                                 revs->tag_objects = 1;
 667                                 revs->tree_objects = 1;
 668                                 revs->blob_objects = 1;
 669                                 continue;
 670                         }
 671                         if (!strcmp(arg, "--objects-edge")) {
 672                                 revs->tag_objects = 1;
 673                                 revs->tree_objects = 1;
 674                                 revs->blob_objects = 1;
 675                                 revs->edge_hint = 1;
 676                                 continue;
 677                         }
 678                         if (!strcmp(arg, "--unpacked")) {
 679                                 revs->unpacked = 1;
 680                                 continue;
 681                         }
 682                         if (!strcmp(arg, "-r")) {
 683                                 revs->diff = 1;
 684                                 revs->diffopt.recursive = 1;
 685                                 continue;
 686                         }
 687                         if (!strcmp(arg, "-t")) {
 688                                 revs->diff = 1;
 689                                 revs->diffopt.recursive = 1;
 690                                 revs->diffopt.tree_in_recursive = 1;
 691                                 continue;
 692                         }
 693                         if (!strcmp(arg, "-m")) {
 694                                 revs->ignore_merges = 0;
 695                                 continue;
 696                         }
 697                         if (!strcmp(arg, "-c")) {
 698                                 revs->diff = 1;
 699                                 revs->dense_combined_merges = 0;
 700                                 revs->combine_merges = 1;
 701                                 continue;
 702                         }
 703                         if (!strcmp(arg, "--cc")) {
 704                                 revs->diff = 1;
 705                                 revs->dense_combined_merges = 1;
 706                                 revs->combine_merges = 1;
 707                                 continue;
 708                         }
 709                         if (!strcmp(arg, "-v")) {
 710                                 revs->verbose_header = 1;
 711                                 continue;
 712                         }
 713                         if (!strncmp(arg, "--pretty", 8)) {
 714                                 revs->verbose_header = 1;
 715                                 revs->commit_format = get_commit_format(arg+8);
 716                                 continue;
 717                         }
 718                         if (!strcmp(arg, "--root")) {
 719                                 revs->show_root_diff = 1;
 720                                 continue;
 721                         }
 722                         if (!strcmp(arg, "--no-commit-id")) {
 723                                 revs->no_commit_id = 1;
 724                                 continue;
 725                         }
 726                         if (!strcmp(arg, "--always")) {
 727                                 revs->always_show_header = 1;
 728                                 continue;
 729                         }
 730                         if (!strcmp(arg, "--no-abbrev")) {
 731                                 revs->abbrev = 0;
 732                                 continue;
 733                         }
 734                         if (!strcmp(arg, "--abbrev")) {
 735                                 revs->abbrev = DEFAULT_ABBREV;
 736                                 continue;
 737                         }
 738                         if (!strncmp(arg, "--abbrev=", 9)) {
 739                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
 740                                 if (revs->abbrev < MINIMUM_ABBREV)
 741                                         revs->abbrev = MINIMUM_ABBREV;
 742                                 else if (revs->abbrev > 40)
 743                                         revs->abbrev = 40;
 744                                 continue;
 745                         }
 746                         if (!strcmp(arg, "--abbrev-commit")) {
 747                                 revs->abbrev_commit = 1;
 748                                 continue;
 749                         }
 750                         if (!strcmp(arg, "--full-diff")) {
 751                                 revs->diff = 1;
 752                                 revs->full_diff = 1;
 753                                 continue;
 754                         }
 755                         if (!strcmp(arg, "--full-history")) {
 756                                 revs->simplify_history = 0;
 757                                 continue;
 758                         }
 759                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
 760                         if (opts > 0) {
 761                                 revs->diff = 1;
 762                                 i += opts - 1;
 763                                 continue;
 764                         }
 765                         *unrecognized++ = arg;
 766                         left++;
 767                         continue;
 768                 }
 769                 dotdot = strstr(arg, "..");
 770                 if (dotdot) {
 771                         unsigned char from_sha1[20];
 772                         const char *next = dotdot + 2;
 773                         const char *this = arg;
 774                         *dotdot = 0;
 775                         if (!*next)
 776                                 next = "HEAD";
 777                         if (dotdot == arg)
 778                                 this = "HEAD";
 779                         if (!get_sha1(this, from_sha1) &&
 780                             !get_sha1(next, sha1)) {
 781                                 struct object *exclude;
 782                                 struct object *include;
 783
 784                                 exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
 785                                 include = get_reference(revs, next, sha1, flags);
 786                                 if (!exclude || !include)
 787                                         die("Invalid revision range %s..%s", arg, next);
 788
 789                                 if (!seen_dashdash) {
 790                                         *dotdot = '.';
 791                                         verify_non_filename(revs->prefix, arg);
 792                                 }
 793                                 add_pending_object(revs, exclude, this);
 794                                 add_pending_object(revs, include, next);
 795                                 continue;
 796                         }
 797                         *dotdot = '.';
 798                 }
 799                 dotdot = strstr(arg, "^@");
 800                 if (dotdot && !dotdot[2]) {
 801                         *dotdot = 0;
 802                         if (add_parents_only(revs, arg, flags))
 803                                 continue;
 804                         *dotdot = '^';
 805                 }
 806                 local_flags = 0;
 807                 if (*arg == '^') {
 808                         local_flags = UNINTERESTING;
 809                         arg++;
 810                 }
 811                 if (get_sha1(arg, sha1)) {
 812                         int j;
 813
 814                         if (seen_dashdash || local_flags)
 815                                 die("bad revision '%s'", arg);
 816
 817                         /* If we didn't have a "--":
 818                          * (1) all filenames must exist;
 819                          * (2) all rev-args must not be interpretable
 820                          *     as a valid filename.
 821                          * but the latter we have checked in the main loop.
 822                          */
 823                         for (j = i; j < argc; j++)
 824                                 verify_filename(revs->prefix, argv[j]);
 825
 826                         revs->prune_data = get_pathspec(revs->prefix, argv + i);
 827                         break;
 828                 }
 829                 if (!seen_dashdash)
 830                         verify_non_filename(revs->prefix, arg);
 831                 object = get_reference(revs, arg, sha1, flags ^ local_flags);
 832                 add_pending_object(revs, object, arg);
 833         }
 834         if (def && !revs->pending.nr) {
 835                 unsigned char sha1[20];
 836                 struct object *object;
 837                 if (get_sha1(def, sha1))
 838                         die("bad default revision '%s'", def);
 839                 object = get_reference(revs, def, sha1, 0);
 840                 add_pending_object(revs, object, def);
 841         }
 842
 843         if (revs->topo_order || revs->unpacked)
 844                 revs->limited = 1;
 845
 846         if (revs->prune_data) {
 847                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
 848                 revs->prune_fn = try_to_simplify_commit;
 849                 if (!revs->full_diff)
 850                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
 851         }
 852         if (revs->combine_merges) {
 853                 revs->ignore_merges = 0;
 854                 if (revs->dense_combined_merges &&
 855                     (revs->diffopt.output_format != DIFF_FORMAT_DIFFSTAT))
 856                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 857         }
 858         revs->diffopt.abbrev = revs->abbrev;
 859         diff_setup_done(&revs->diffopt);
 860
 861         return left;
 862 }
 863
 864 void prepare_revision_walk(struct rev_info *revs)
 865 {
 866         int nr = revs->pending.nr;
 867         struct object_array_entry *list = revs->pending.objects;
 868
 869         revs->pending.nr = 0;
 870         revs->pending.alloc = 0;
 871         revs->pending.objects = NULL;
 872         while (--nr >= 0) {
 873                 struct commit *commit = handle_commit(revs, list->item, list->name);
 874                 if (commit) {
 875                         if (!(commit->object.flags & SEEN)) {
 876                                 commit->object.flags |= SEEN;
 877                                 insert_by_date(commit, &revs->commits);
 878                         }
 879                 }
 880                 list++;
 881         }
 882
 883         if (revs->no_walk)
 884                 return;
 885         if (revs->limited)
 886                 limit_list(revs);
 887         if (revs->topo_order)
 888                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
 889                                              revs->topo_setter,
 890                                              revs->topo_getter);
 891 }
 892
 893 static int rewrite_one(struct rev_info *revs, struct commit **pp)
 894 {
 895         for (;;) {
 896                 struct commit *p = *pp;
 897                 if (!revs->limited)
 898                         add_parents_to_list(revs, p, &revs->commits);
 899                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
 900                         return 0;
 901                 if (!p->parents)
 902                         return -1;
 903                 *pp = p->parents->item;
 904         }
 905 }
 906
 907 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
 908 {
 909         struct commit_list **pp = &commit->parents;
 910         while (*pp) {
 911                 struct commit_list *parent = *pp;
 912                 if (rewrite_one(revs, &parent->item) < 0) {
 913                         *pp = parent->next;
 914                         continue;
 915                 }
 916                 pp = &parent->next;
 917         }
 918 }
 919
 920 static void mark_boundary_to_show(struct commit *commit)
 921 {
 922         struct commit_list *p = commit->parents;
 923         while (p) {
 924                 commit = p->item;
 925                 p = p->next;
 926                 if (commit->object.flags & BOUNDARY)
 927                         commit->object.flags |= BOUNDARY_SHOW;
 928         }
 929 }
 930
 931 struct commit *get_revision(struct rev_info *revs)
 932 {
 933         struct commit_list *list = revs->commits;
 934
 935         if (!list)
 936                 return NULL;
 937
 938         /* Check the max_count ... */
 939         switch (revs->max_count) {
 940         case -1:
 941                 break;
 942         case 0:
 943                 return NULL;
 944         default:
 945                 revs->max_count--;
 946         }
 947
 948         do {
 949                 struct commit_list *entry = revs->commits;
 950                 struct commit *commit = entry->item;
 951
 952                 revs->commits = entry->next;
 953                 free(entry);
 954
 955                 /*
 956                  * If we haven't done the list limiting, we need to look at
 957                  * the parents here. We also need to do the date-based limiting
 958                  * that we'd otherwise have done in limit_list().
 959                  */
 960                 if (!revs->limited) {
 961                         if ((revs->unpacked &&
 962                              has_sha1_pack(commit->object.sha1)) ||
 963                             (revs->max_age != -1 &&
 964                              (commit->date < revs->max_age)))
 965                                 continue;
 966                         add_parents_to_list(revs, commit, &revs->commits);
 967                 }
 968                 if (commit->object.flags & SHOWN)
 969                         continue;
 970
 971                 /* We want to show boundary commits only when their
 972                  * children are shown.  When path-limiter is in effect,
 973                  * rewrite_parents() drops some commits from getting shown,
 974                  * and there is no point showing boundary parents that
 975                  * are not shown.  After rewrite_parents() rewrites the
 976                  * parents of a commit that is shown, we mark the boundary
 977                  * parents with BOUNDARY_SHOW.
 978                  */
 979                 if (commit->object.flags & BOUNDARY_SHOW) {
 980                         commit->object.flags |= SHOWN;
 981                         return commit;
 982                 }
 983                 if (commit->object.flags & UNINTERESTING)
 984                         continue;
 985                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 986                         continue;
 987                 if (revs->no_merges &&
 988                     commit->parents && commit->parents->next)
 989                         continue;
 990                 if (revs->prune_fn && revs->dense) {
 991                         if (!(commit->object.flags & TREECHANGE))
 992                                 continue;
 993                         if (revs->parents)
 994                                 rewrite_parents(revs, commit);
 995                 }
 996                 if (revs->boundary)
 997                         mark_boundary_to_show(commit);
 998                 commit->object.flags |= SHOWN;
 999                 return commit;
1000         } while (revs->commits);
1001         return NULL;
1002 }