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 struct object_list **add_object(struct object *obj,
  35                                        struct object_list **p,
  36                                        struct name_path *path,
  37                                        const char *name)
  38 {
  39         struct object_list *entry = xmalloc(sizeof(*entry));
  40         entry->item = obj;
  41         entry->next = *p;
  42         entry->name = path_name(path, name);
  43         *p = entry;
  44         return &entry->next;
  45 }
  46
  47 static void mark_blob_uninteresting(struct blob *blob)
  48 {
  49         if (blob->object.flags & UNINTERESTING)
  50                 return;
  51         blob->object.flags |= UNINTERESTING;
  52 }
  53
  54 void mark_tree_uninteresting(struct tree *tree)
  55 {
  56         struct object *obj = &tree->object;
  57         struct tree_entry_list *entry;
  58
  59         if (obj->flags & UNINTERESTING)
  60                 return;
  61         obj->flags |= UNINTERESTING;
  62         if (!has_sha1_file(obj->sha1))
  63                 return;
  64         if (parse_tree(tree) < 0)
  65                 die("bad tree %s", sha1_to_hex(obj->sha1));
  66         entry = tree->entries;
  67         tree->entries = NULL;
  68         while (entry) {
  69                 struct tree_entry_list *next = entry->next;
  70                 if (entry->directory)
  71                         mark_tree_uninteresting(entry->item.tree);
  72                 else
  73                         mark_blob_uninteresting(entry->item.blob);
  74                 free(entry);
  75                 entry = next;
  76         }
  77 }
  78
  79 void mark_parents_uninteresting(struct commit *commit)
  80 {
  81         struct commit_list *parents = commit->parents;
  82
  83         while (parents) {
  84                 struct commit *commit = parents->item;
  85                 if (!(commit->object.flags & UNINTERESTING)) {
  86                         commit->object.flags |= UNINTERESTING;
  87
  88                         /*
  89                          * Normally we haven't parsed the parent
  90                          * yet, so we won't have a parent of a parent
  91                          * here. However, it may turn out that we've
  92                          * reached this commit some other way (where it
  93                          * wasn't uninteresting), in which case we need
  94                          * to mark its parents recursively too..
  95                          */
  96                         if (commit->parents)
  97                                 mark_parents_uninteresting(commit);
  98                 }
  99
 100                 /*
 101                  * A missing commit is ok iff its parent is marked
 102                  * uninteresting.
 103                  *
 104                  * We just mark such a thing parsed, so that when
 105                  * it is popped next time around, we won't be trying
 106                  * to parse it and get an error.
 107                  */
 108                 if (!has_sha1_file(commit->object.sha1))
 109                         commit->object.parsed = 1;
 110                 parents = parents->next;
 111         }
 112 }
 113
 114 static void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 115 {
 116         add_object(obj, &revs->pending_objects, NULL, name);
 117 }
 118
 119 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 120 {
 121         struct object *object;
 122
 123         object = parse_object(sha1);
 124         if (!object)
 125                 die("bad object %s", name);
 126         object->flags |= flags;
 127         return object;
 128 }
 129
 130 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 131 {
 132         unsigned long flags = object->flags;
 133
 134         /*
 135          * Tag object? Look what it points to..
 136          */
 137         while (object->type == tag_type) {
 138                 struct tag *tag = (struct tag *) object;
 139                 if (revs->tag_objects && !(flags & UNINTERESTING))
 140                         add_pending_object(revs, object, tag->tag);
 141                 object = parse_object(tag->tagged->sha1);
 142                 if (!object)
 143                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 144         }
 145
 146         /*
 147          * Commit object? Just return it, we'll do all the complex
 148          * reachability crud.
 149          */
 150         if (object->type == commit_type) {
 151                 struct commit *commit = (struct commit *)object;
 152                 if (parse_commit(commit) < 0)
 153                         die("unable to parse commit %s", name);
 154                 if (flags & UNINTERESTING) {
 155                         mark_parents_uninteresting(commit);
 156                         revs->limited = 1;
 157                 }
 158                 return commit;
 159         }
 160
 161         /*
 162          * Tree object? Either mark it uniniteresting, or add it
 163          * to the list of objects to look at later..
 164          */
 165         if (object->type == tree_type) {
 166                 struct tree *tree = (struct tree *)object;
 167                 if (!revs->tree_objects)
 168                         return NULL;
 169                 if (flags & UNINTERESTING) {
 170                         mark_tree_uninteresting(tree);
 171                         return NULL;
 172                 }
 173                 add_pending_object(revs, object, "");
 174                 return NULL;
 175         }
 176
 177         /*
 178          * Blob object? You know the drill by now..
 179          */
 180         if (object->type == blob_type) {
 181                 struct blob *blob = (struct blob *)object;
 182                 if (!revs->blob_objects)
 183                         return NULL;
 184                 if (flags & UNINTERESTING) {
 185                         mark_blob_uninteresting(blob);
 186                         return NULL;
 187                 }
 188                 add_pending_object(revs, object, "");
 189                 return NULL;
 190         }
 191         die("%s is unknown object", name);
 192 }
 193
 194 static int everybody_uninteresting(struct commit_list *orig)
 195 {
 196         struct commit_list *list = orig;
 197         while (list) {
 198                 struct commit *commit = list->item;
 199                 list = list->next;
 200                 if (commit->object.flags & UNINTERESTING)
 201                         continue;
 202                 return 0;
 203         }
 204         return 1;
 205 }
 206
 207 static int tree_difference = REV_TREE_SAME;
 208
 209 static void file_add_remove(struct diff_options *options,
 210                     int addremove, unsigned mode,
 211                     const unsigned char *sha1,
 212                     const char *base, const char *path)
 213 {
 214         int diff = REV_TREE_DIFFERENT;
 215
 216         /*
 217          * Is it an add of a new file? It means that the old tree
 218          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 219          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 220          * (and if it already was "REV_TREE_NEW", we'll keep it
 221          * "REV_TREE_NEW" of course).
 222          */
 223         if (addremove == '+') {
 224                 diff = tree_difference;
 225                 if (diff != REV_TREE_SAME)
 226                         return;
 227                 diff = REV_TREE_NEW;
 228         }
 229         tree_difference = diff;
 230 }
 231
 232 static void file_change(struct diff_options *options,
 233                  unsigned old_mode, unsigned new_mode,
 234                  const unsigned char *old_sha1,
 235                  const unsigned char *new_sha1,
 236                  const char *base, const char *path)
 237 {
 238         tree_difference = REV_TREE_DIFFERENT;
 239 }
 240
 241 int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 242 {
 243         if (!t1)
 244                 return REV_TREE_NEW;
 245         if (!t2)
 246                 return REV_TREE_DIFFERENT;
 247         tree_difference = REV_TREE_SAME;
 248         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 249                            &revs->pruning) < 0)
 250                 return REV_TREE_DIFFERENT;
 251         return tree_difference;
 252 }
 253
 254 int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 255 {
 256         int retval;
 257         void *tree;
 258         struct tree_desc empty, real;
 259
 260         if (!t1)
 261                 return 0;
 262
 263         tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
 264         if (!tree)
 265                 return 0;
 266         real.buf = tree;
 267
 268         empty.buf = "";
 269         empty.size = 0;
 270
 271         tree_difference = 0;
 272         retval = diff_tree(&empty, &real, "", &revs->pruning);
 273         free(tree);
 274
 275         return retval >= 0 && !tree_difference;
 276 }
 277
 278 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 279 {
 280         struct commit_list **pp, *parent;
 281         int tree_changed = 0;
 282
 283         if (!commit->tree)
 284                 return;
 285
 286         if (!commit->parents) {
 287                 if (!rev_same_tree_as_empty(revs, commit->tree))
 288                         commit->object.flags |= TREECHANGE;
 289                 return;
 290         }
 291
 292         pp = &commit->parents;
 293         while ((parent = *pp) != NULL) {
 294                 struct commit *p = parent->item;
 295
 296                 parse_commit(p);
 297                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 298                 case REV_TREE_SAME:
 299                         if (p->object.flags & UNINTERESTING) {
 300                                 /* Even if a merge with an uninteresting
 301                                  * side branch brought the entire change
 302                                  * we are interested in, we do not want
 303                                  * to lose the other branches of this
 304                                  * merge, so we just keep going.
 305                                  */
 306                                 pp = &parent->next;
 307                                 continue;
 308                         }
 309                         parent->next = NULL;
 310                         commit->parents = parent;
 311                         return;
 312
 313                 case REV_TREE_NEW:
 314                         if (revs->remove_empty_trees &&
 315                             rev_same_tree_as_empty(revs, p->tree)) {
 316                                 /* We are adding all the specified
 317                                  * paths from this parent, so the
 318                                  * history beyond this parent is not
 319                                  * interesting.  Remove its parents
 320                                  * (they are grandparents for us).
 321                                  * IOW, we pretend this parent is a
 322                                  * "root" commit.
 323                                  */
 324                                 parse_commit(p);
 325                                 p->parents = NULL;
 326                         }
 327                 /* fallthrough */
 328                 case REV_TREE_DIFFERENT:
 329                         tree_changed = 1;
 330                         pp = &parent->next;
 331                         continue;
 332                 }
 333                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 334         }
 335         if (tree_changed)
 336                 commit->object.flags |= TREECHANGE;
 337 }
 338
 339 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 340 {
 341         struct commit_list *parent = commit->parents;
 342
 343         if (commit->object.flags & ADDED)
 344                 return;
 345         commit->object.flags |= ADDED;
 346
 347         /*
 348          * If the commit is uninteresting, don't try to
 349          * prune parents - we want the maximal uninteresting
 350          * set.
 351          *
 352          * Normally we haven't parsed the parent
 353          * yet, so we won't have a parent of a parent
 354          * here. However, it may turn out that we've
 355          * reached this commit some other way (where it
 356          * wasn't uninteresting), in which case we need
 357          * to mark its parents recursively too..
 358          */
 359         if (commit->object.flags & UNINTERESTING) {
 360                 while (parent) {
 361                         struct commit *p = parent->item;
 362                         parent = parent->next;
 363                         parse_commit(p);
 364                         p->object.flags |= UNINTERESTING;
 365                         if (p->parents)
 366                                 mark_parents_uninteresting(p);
 367                         if (p->object.flags & SEEN)
 368                                 continue;
 369                         p->object.flags |= SEEN;
 370                         insert_by_date(p, list);
 371                 }
 372                 return;
 373         }
 374
 375         /*
 376          * Ok, the commit wasn't uninteresting. Try to
 377          * simplify the commit history and find the parent
 378          * that has no differences in the path set if one exists.
 379          */
 380         if (revs->prune_fn)
 381                 revs->prune_fn(revs, commit);
 382
 383         if (revs->no_walk)
 384                 return;
 385
 386         parent = commit->parents;
 387         while (parent) {
 388                 struct commit *p = parent->item;
 389
 390                 parent = parent->next;
 391
 392                 parse_commit(p);
 393                 if (p->object.flags & SEEN)
 394                         continue;
 395                 p->object.flags |= SEEN;
 396                 insert_by_date(p, list);
 397         }
 398 }
 399
 400 static void limit_list(struct rev_info *revs)
 401 {
 402         struct commit_list *list = revs->commits;
 403         struct commit_list *newlist = NULL;
 404         struct commit_list **p = &newlist;
 405
 406         while (list) {
 407                 struct commit_list *entry = list;
 408                 struct commit *commit = list->item;
 409                 struct object *obj = &commit->object;
 410
 411                 list = list->next;
 412                 free(entry);
 413
 414                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 415                         obj->flags |= UNINTERESTING;
 416                 if (revs->unpacked && has_sha1_pack(obj->sha1))
 417                         obj->flags |= UNINTERESTING;
 418                 add_parents_to_list(revs, commit, &list);
 419                 if (obj->flags & UNINTERESTING) {
 420                         mark_parents_uninteresting(commit);
 421                         if (everybody_uninteresting(list))
 422                                 break;
 423                         continue;
 424                 }
 425                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 426                         continue;
 427                 p = &commit_list_insert(commit, p)->next;
 428         }
 429         if (revs->boundary) {
 430                 /* mark the ones that are on the result list first */
 431                 for (list = newlist; list; list = list->next) {
 432                         struct commit *commit = list->item;
 433                         commit->object.flags |= TMP_MARK;
 434                 }
 435                 for (list = newlist; list; list = list->next) {
 436                         struct commit *commit = list->item;
 437                         struct object *obj = &commit->object;
 438                         struct commit_list *parent;
 439                         if (obj->flags & UNINTERESTING)
 440                                 continue;
 441                         for (parent = commit->parents;
 442                              parent;
 443                              parent = parent->next) {
 444                                 struct commit *pcommit = parent->item;
 445                                 if (!(pcommit->object.flags & UNINTERESTING))
 446                                         continue;
 447                                 pcommit->object.flags |= BOUNDARY;
 448                                 if (pcommit->object.flags & TMP_MARK)
 449                                         continue;
 450                                 pcommit->object.flags |= TMP_MARK;
 451                                 p = &commit_list_insert(pcommit, p)->next;
 452                         }
 453                 }
 454                 for (list = newlist; list; list = list->next) {
 455                         struct commit *commit = list->item;
 456                         commit->object.flags &= ~TMP_MARK;
 457                 }
 458         }
 459         revs->commits = newlist;
 460 }
 461
 462 static int all_flags;
 463 static struct rev_info *all_revs;
 464
 465 static int handle_one_ref(const char *path, const unsigned char *sha1)
 466 {
 467         struct object *object = get_reference(all_revs, path, sha1, all_flags);
 468         add_pending_object(all_revs, object, "");
 469         return 0;
 470 }
 471
 472 static void handle_all(struct rev_info *revs, unsigned flags)
 473 {
 474         all_revs = revs;
 475         all_flags = flags;
 476         for_each_ref(handle_one_ref);
 477 }
 478
 479 void init_revisions(struct rev_info *revs)
 480 {
 481         memset(revs, 0, sizeof(*revs));
 482
 483         revs->abbrev = DEFAULT_ABBREV;
 484         revs->ignore_merges = 1;
 485         revs->pruning.recursive = 1;
 486         revs->pruning.add_remove = file_add_remove;
 487         revs->pruning.change = file_change;
 488         revs->lifo = 1;
 489         revs->dense = 1;
 490         revs->prefix = setup_git_directory();
 491         revs->max_age = -1;
 492         revs->min_age = -1;
 493         revs->max_count = -1;
 494
 495         revs->prune_fn = NULL;
 496         revs->prune_data = NULL;
 497
 498         revs->topo_setter = topo_sort_default_setter;
 499         revs->topo_getter = topo_sort_default_getter;
 500
 501         revs->header_prefix = "";
 502         revs->commit_format = CMIT_FMT_DEFAULT;
 503
 504         diff_setup(&revs->diffopt);
 505 }
 506
 507 /*
 508  * Parse revision information, filling in the "rev_info" structure,
 509  * and removing the used arguments from the argument list.
 510  *
 511  * Returns the number of arguments left that weren't recognized
 512  * (which are also moved to the head of the argument list)
 513  */
 514 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 515 {
 516         int i, flags, seen_dashdash;
 517         const char **unrecognized = argv + 1;
 518         int left = 1;
 519
 520         /* First, search for "--" */
 521         seen_dashdash = 0;
 522         for (i = 1; i < argc; i++) {
 523                 const char *arg = argv[i];
 524                 if (strcmp(arg, "--"))
 525                         continue;
 526                 argv[i] = NULL;
 527                 argc = i;
 528                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 529                 seen_dashdash = 1;
 530                 break;
 531         }
 532
 533         flags = 0;
 534         for (i = 1; i < argc; i++) {
 535                 struct object *object;
 536                 const char *arg = argv[i];
 537                 unsigned char sha1[20];
 538                 char *dotdot;
 539                 int local_flags;
 540
 541                 if (*arg == '-') {
 542                         int opts;
 543                         if (!strncmp(arg, "--max-count=", 12)) {
 544                                 revs->max_count = atoi(arg + 12);
 545                                 continue;
 546                         }
 547                         /* accept -<digit>, like traditilnal "head" */
 548                         if ((*arg == '-') && isdigit(arg[1])) {
 549                                 revs->max_count = atoi(arg + 1);
 550                                 continue;
 551                         }
 552                         if (!strcmp(arg, "-n")) {
 553                                 if (argc <= i + 1)
 554                                         die("-n requires an argument");
 555                                 revs->max_count = atoi(argv[++i]);
 556                                 continue;
 557                         }
 558                         if (!strncmp(arg,"-n",2)) {
 559                                 revs->max_count = atoi(arg + 2);
 560                                 continue;
 561                         }
 562                         if (!strncmp(arg, "--max-age=", 10)) {
 563                                 revs->max_age = atoi(arg + 10);
 564                                 continue;
 565                         }
 566                         if (!strncmp(arg, "--since=", 8)) {
 567                                 revs->max_age = approxidate(arg + 8);
 568                                 continue;
 569                         }
 570                         if (!strncmp(arg, "--after=", 8)) {
 571                                 revs->max_age = approxidate(arg + 8);
 572                                 continue;
 573                         }
 574                         if (!strncmp(arg, "--min-age=", 10)) {
 575                                 revs->min_age = atoi(arg + 10);
 576                                 continue;
 577                         }
 578                         if (!strncmp(arg, "--before=", 9)) {
 579                                 revs->min_age = approxidate(arg + 9);
 580                                 continue;
 581                         }
 582                         if (!strncmp(arg, "--until=", 8)) {
 583                                 revs->min_age = approxidate(arg + 8);
 584                                 continue;
 585                         }
 586                         if (!strcmp(arg, "--all")) {
 587                                 handle_all(revs, flags);
 588                                 continue;
 589                         }
 590                         if (!strcmp(arg, "--not")) {
 591                                 flags ^= UNINTERESTING;
 592                                 continue;
 593                         }
 594                         if (!strcmp(arg, "--default")) {
 595                                 if (++i >= argc)
 596                                         die("bad --default argument");
 597                                 def = argv[i];
 598                                 continue;
 599                         }
 600                         if (!strcmp(arg, "--topo-order")) {
 601                                 revs->topo_order = 1;
 602                                 continue;
 603                         }
 604                         if (!strcmp(arg, "--date-order")) {
 605                                 revs->lifo = 0;
 606                                 revs->topo_order = 1;
 607                                 continue;
 608                         }
 609                         if (!strcmp(arg, "--parents")) {
 610                                 revs->parents = 1;
 611                                 continue;
 612                         }
 613                         if (!strcmp(arg, "--dense")) {
 614                                 revs->dense = 1;
 615                                 continue;
 616                         }
 617                         if (!strcmp(arg, "--sparse")) {
 618                                 revs->dense = 0;
 619                                 continue;
 620                         }
 621                         if (!strcmp(arg, "--remove-empty")) {
 622                                 revs->remove_empty_trees = 1;
 623                                 continue;
 624                         }
 625                         if (!strcmp(arg, "--no-merges")) {
 626                                 revs->no_merges = 1;
 627                                 continue;
 628                         }
 629                         if (!strcmp(arg, "--boundary")) {
 630                                 revs->boundary = 1;
 631                                 continue;
 632                         }
 633                         if (!strcmp(arg, "--objects")) {
 634                                 revs->tag_objects = 1;
 635                                 revs->tree_objects = 1;
 636                                 revs->blob_objects = 1;
 637                                 continue;
 638                         }
 639                         if (!strcmp(arg, "--objects-edge")) {
 640                                 revs->tag_objects = 1;
 641                                 revs->tree_objects = 1;
 642                                 revs->blob_objects = 1;
 643                                 revs->edge_hint = 1;
 644                                 continue;
 645                         }
 646                         if (!strcmp(arg, "--unpacked")) {
 647                                 revs->unpacked = 1;
 648                                 continue;
 649                         }
 650                         if (!strcmp(arg, "-r")) {
 651                                 revs->diff = 1;
 652                                 revs->diffopt.recursive = 1;
 653                                 continue;
 654                         }
 655                         if (!strcmp(arg, "-t")) {
 656                                 revs->diff = 1;
 657                                 revs->diffopt.recursive = 1;
 658                                 revs->diffopt.tree_in_recursive = 1;
 659                                 continue;
 660                         }
 661                         if (!strcmp(arg, "-m")) {
 662                                 revs->ignore_merges = 0;
 663                                 continue;
 664                         }
 665                         if (!strcmp(arg, "-c")) {
 666                                 revs->diff = 1;
 667                                 revs->combine_merges = 1;
 668                                 continue;
 669                         }
 670                         if (!strcmp(arg, "--cc")) {
 671                                 revs->diff = 1;
 672                                 revs->dense_combined_merges = 1;
 673                                 revs->combine_merges = 1;
 674                                 continue;
 675                         }
 676                         if (!strcmp(arg, "-v")) {
 677                                 revs->verbose_header = 1;
 678                                 revs->header_prefix = "diff-tree ";
 679                                 continue;
 680                         }
 681                         if (!strncmp(arg, "--pretty", 8)) {
 682                                 revs->verbose_header = 1;
 683                                 revs->header_prefix = "diff-tree ";
 684                                 revs->commit_format = get_commit_format(arg+8);
 685                                 continue;
 686                         }
 687                         if (!strcmp(arg, "--root")) {
 688                                 revs->show_root_diff = 1;
 689                                 continue;
 690                         }
 691                         if (!strcmp(arg, "--no-commit-id")) {
 692                                 revs->no_commit_id = 1;
 693                                 continue;
 694                         }
 695                         if (!strcmp(arg, "--always")) {
 696                                 revs->always_show_header = 1;
 697                                 continue;
 698                         }
 699                         if (!strcmp(arg, "--no-abbrev")) {
 700                                 revs->abbrev = 0;
 701                                 continue;
 702                         }
 703                         if (!strcmp(arg, "--abbrev")) {
 704                                 revs->abbrev = DEFAULT_ABBREV;
 705                                 continue;
 706                         }
 707                         if (!strcmp(arg, "--abbrev-commit")) {
 708                                 revs->abbrev_commit = 1;
 709                                 continue;
 710                         }
 711                         if (!strcmp(arg, "--full-diff")) {
 712                                 revs->diff = 1;
 713                                 revs->full_diff = 1;
 714                                 continue;
 715                         }
 716                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
 717                         if (opts > 0) {
 718                                 revs->diff = 1;
 719                                 i += opts - 1;
 720                                 continue;
 721                         }
 722                         *unrecognized++ = arg;
 723                         left++;
 724                         continue;
 725                 }
 726                 dotdot = strstr(arg, "..");
 727                 if (dotdot) {
 728                         unsigned char from_sha1[20];
 729                         const char *next = dotdot + 2;
 730                         const char *this = arg;
 731                         *dotdot = 0;
 732                         if (!*next)
 733                                 next = "HEAD";
 734                         if (dotdot == arg)
 735                                 this = "HEAD";
 736                         if (!get_sha1(this, from_sha1) &&
 737                             !get_sha1(next, sha1)) {
 738                                 struct object *exclude;
 739                                 struct object *include;
 740
 741                                 exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
 742                                 include = get_reference(revs, next, sha1, flags);
 743                                 if (!exclude || !include)
 744                                         die("Invalid revision range %s..%s", arg, next);
 745                                 add_pending_object(revs, exclude, this);
 746                                 add_pending_object(revs, include, next);
 747                                 continue;
 748                         }
 749                         *dotdot = '.';
 750                 }
 751                 local_flags = 0;
 752                 if (*arg == '^') {
 753                         local_flags = UNINTERESTING;
 754                         arg++;
 755                 }
 756                 if (get_sha1(arg, sha1) < 0) {
 757                         struct stat st;
 758                         int j;
 759
 760                         if (seen_dashdash || local_flags)
 761                                 die("bad revision '%s'", arg);
 762
 763                         /* If we didn't have a "--", all filenames must exist */
 764                         for (j = i; j < argc; j++) {
 765                                 if (lstat(argv[j], &st) < 0)
 766                                         die("'%s': %s", argv[j], strerror(errno));
 767                         }
 768                         revs->prune_data = get_pathspec(revs->prefix, argv + i);
 769                         break;
 770                 }
 771                 object = get_reference(revs, arg, sha1, flags ^ local_flags);
 772                 add_pending_object(revs, object, arg);
 773         }
 774         if (def && !revs->pending_objects) {
 775                 unsigned char sha1[20];
 776                 struct object *object;
 777                 if (get_sha1(def, sha1) < 0)
 778                         die("bad default revision '%s'", def);
 779                 object = get_reference(revs, def, sha1, 0);
 780                 add_pending_object(revs, object, def);
 781         }
 782
 783         if (revs->topo_order || revs->unpacked)
 784                 revs->limited = 1;
 785
 786         if (revs->prune_data) {
 787                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
 788                 revs->prune_fn = try_to_simplify_commit;
 789                 if (!revs->full_diff)
 790                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
 791         }
 792         if (revs->combine_merges) {
 793                 revs->ignore_merges = 0;
 794                 if (revs->dense_combined_merges)
 795                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 796         }
 797         if (revs->diffopt.output_format == DIFF_FORMAT_PATCH)
 798                 revs->diffopt.recursive = 1;
 799         revs->diffopt.abbrev = revs->abbrev;
 800         diff_setup_done(&revs->diffopt);
 801
 802         return left;
 803 }
 804
 805 void prepare_revision_walk(struct rev_info *revs)
 806 {
 807         struct object_list *list;
 808
 809         list = revs->pending_objects;
 810         revs->pending_objects = NULL;
 811         while (list) {
 812                 struct commit *commit = handle_commit(revs, list->item, list->name);
 813                 if (commit) {
 814                         if (!(commit->object.flags & SEEN)) {
 815                                 commit->object.flags |= SEEN;
 816                                 insert_by_date(commit, &revs->commits);
 817                         }
 818                 }
 819                 list = list->next;
 820         }
 821
 822         if (revs->no_walk)
 823                 return;
 824         if (revs->limited)
 825                 limit_list(revs);
 826         if (revs->topo_order)
 827                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
 828                                              revs->topo_setter,
 829                                              revs->topo_getter);
 830 }
 831
 832 static int rewrite_one(struct rev_info *revs, struct commit **pp)
 833 {
 834         for (;;) {
 835                 struct commit *p = *pp;
 836                 if (!revs->limited)
 837                         add_parents_to_list(revs, p, &revs->commits);
 838                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
 839                         return 0;
 840                 if (!p->parents)
 841                         return -1;
 842                 *pp = p->parents->item;
 843         }
 844 }
 845
 846 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
 847 {
 848         struct commit_list **pp = &commit->parents;
 849         while (*pp) {
 850                 struct commit_list *parent = *pp;
 851                 if (rewrite_one(revs, &parent->item) < 0) {
 852                         *pp = parent->next;
 853                         continue;
 854                 }
 855                 pp = &parent->next;
 856         }
 857 }
 858
 859 struct commit *get_revision(struct rev_info *revs)
 860 {
 861         struct commit_list *list = revs->commits;
 862
 863         if (!list)
 864                 return NULL;
 865
 866         /* Check the max_count ... */
 867         switch (revs->max_count) {
 868         case -1:
 869                 break;
 870         case 0:
 871                 return NULL;
 872         default:
 873                 revs->max_count--;
 874         }
 875
 876         do {
 877                 struct commit *commit = revs->commits->item;
 878
 879                 revs->commits = revs->commits->next;
 880
 881                 /*
 882                  * If we haven't done the list limiting, we need to look at
 883                  * the parents here. We also need to do the date-based limiting
 884                  * that we'd otherwise have done in limit_list().
 885                  */
 886                 if (!revs->limited) {
 887                         if ((revs->unpacked &&
 888                              has_sha1_pack(commit->object.sha1)) ||
 889                             (revs->max_age != -1 &&
 890                              (commit->date < revs->max_age)))
 891                                 continue;
 892                         add_parents_to_list(revs, commit, &revs->commits);
 893                 }
 894                 if (commit->object.flags & SHOWN)
 895                         continue;
 896                 if (!(commit->object.flags & BOUNDARY) &&
 897                     (commit->object.flags & UNINTERESTING))
 898                         continue;
 899                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 900                         continue;
 901                 if (revs->no_merges &&
 902                     commit->parents && commit->parents->next)
 903                         continue;
 904                 if (revs->prune_fn && revs->dense) {
 905                         if (!(commit->object.flags & TREECHANGE))
 906                                 continue;
 907                         if (revs->parents)
 908                                 rewrite_parents(revs, commit);
 909                 }
 910                 commit->object.flags |= SHOWN;
 911                 return commit;
 912         } while (revs->commits);
 913         return NULL;
 914 }