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                         commit->object.flags |= UNINTERESTING;
 156                         mark_parents_uninteresting(commit);
 157                         revs->limited = 1;
 158                 }
 159                 return commit;
 160         }
 161
 162         /*
 163          * Tree object? Either mark it uniniteresting, or add it
 164          * to the list of objects to look at later..
 165          */
 166         if (object->type == tree_type) {
 167                 struct tree *tree = (struct tree *)object;
 168                 if (!revs->tree_objects)
 169                         return NULL;
 170                 if (flags & UNINTERESTING) {
 171                         mark_tree_uninteresting(tree);
 172                         return NULL;
 173                 }
 174                 add_pending_object(revs, object, "");
 175                 return NULL;
 176         }
 177
 178         /*
 179          * Blob object? You know the drill by now..
 180          */
 181         if (object->type == blob_type) {
 182                 struct blob *blob = (struct blob *)object;
 183                 if (!revs->blob_objects)
 184                         return NULL;
 185                 if (flags & UNINTERESTING) {
 186                         mark_blob_uninteresting(blob);
 187                         return NULL;
 188                 }
 189                 add_pending_object(revs, object, "");
 190                 return NULL;
 191         }
 192         die("%s is unknown object", name);
 193 }
 194
 195 static int everybody_uninteresting(struct commit_list *orig)
 196 {
 197         struct commit_list *list = orig;
 198         while (list) {
 199                 struct commit *commit = list->item;
 200                 list = list->next;
 201                 if (commit->object.flags & UNINTERESTING)
 202                         continue;
 203                 return 0;
 204         }
 205         return 1;
 206 }
 207
 208 static int tree_difference = REV_TREE_SAME;
 209
 210 static void file_add_remove(struct diff_options *options,
 211                     int addremove, unsigned mode,
 212                     const unsigned char *sha1,
 213                     const char *base, const char *path)
 214 {
 215         int diff = REV_TREE_DIFFERENT;
 216
 217         /*
 218          * Is it an add of a new file? It means that the old tree
 219          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 220          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 221          * (and if it already was "REV_TREE_NEW", we'll keep it
 222          * "REV_TREE_NEW" of course).
 223          */
 224         if (addremove == '+') {
 225                 diff = tree_difference;
 226                 if (diff != REV_TREE_SAME)
 227                         return;
 228                 diff = REV_TREE_NEW;
 229         }
 230         tree_difference = diff;
 231 }
 232
 233 static void file_change(struct diff_options *options,
 234                  unsigned old_mode, unsigned new_mode,
 235                  const unsigned char *old_sha1,
 236                  const unsigned char *new_sha1,
 237                  const char *base, const char *path)
 238 {
 239         tree_difference = REV_TREE_DIFFERENT;
 240 }
 241
 242 int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 243 {
 244         if (!t1)
 245                 return REV_TREE_NEW;
 246         if (!t2)
 247                 return REV_TREE_DIFFERENT;
 248         tree_difference = REV_TREE_SAME;
 249         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 250                            &revs->pruning) < 0)
 251                 return REV_TREE_DIFFERENT;
 252         return tree_difference;
 253 }
 254
 255 int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 256 {
 257         int retval;
 258         void *tree;
 259         struct tree_desc empty, real;
 260
 261         if (!t1)
 262                 return 0;
 263
 264         tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
 265         if (!tree)
 266                 return 0;
 267         real.buf = tree;
 268
 269         empty.buf = "";
 270         empty.size = 0;
 271
 272         tree_difference = 0;
 273         retval = diff_tree(&empty, &real, "", &revs->pruning);
 274         free(tree);
 275
 276         return retval >= 0 && !tree_difference;
 277 }
 278
 279 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 280 {
 281         struct commit_list **pp, *parent;
 282         int tree_changed = 0;
 283
 284         if (!commit->tree)
 285                 return;
 286
 287         if (!commit->parents) {
 288                 if (!rev_same_tree_as_empty(revs, commit->tree))
 289                         commit->object.flags |= TREECHANGE;
 290                 return;
 291         }
 292
 293         pp = &commit->parents;
 294         while ((parent = *pp) != NULL) {
 295                 struct commit *p = parent->item;
 296
 297                 parse_commit(p);
 298                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 299                 case REV_TREE_SAME:
 300                         if (p->object.flags & UNINTERESTING) {
 301                                 /* Even if a merge with an uninteresting
 302                                  * side branch brought the entire change
 303                                  * we are interested in, we do not want
 304                                  * to lose the other branches of this
 305                                  * merge, so we just keep going.
 306                                  */
 307                                 pp = &parent->next;
 308                                 continue;
 309                         }
 310                         parent->next = NULL;
 311                         commit->parents = parent;
 312                         return;
 313
 314                 case REV_TREE_NEW:
 315                         if (revs->remove_empty_trees &&
 316                             rev_same_tree_as_empty(revs, p->tree)) {
 317                                 /* We are adding all the specified
 318                                  * paths from this parent, so the
 319                                  * history beyond this parent is not
 320                                  * interesting.  Remove its parents
 321                                  * (they are grandparents for us).
 322                                  * IOW, we pretend this parent is a
 323                                  * "root" commit.
 324                                  */
 325                                 parse_commit(p);
 326                                 p->parents = NULL;
 327                         }
 328                 /* fallthrough */
 329                 case REV_TREE_DIFFERENT:
 330                         tree_changed = 1;
 331                         pp = &parent->next;
 332                         continue;
 333                 }
 334                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 335         }
 336         if (tree_changed)
 337                 commit->object.flags |= TREECHANGE;
 338 }
 339
 340 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 341 {
 342         struct commit_list *parent = commit->parents;
 343
 344         if (commit->object.flags & ADDED)
 345                 return;
 346         commit->object.flags |= ADDED;
 347
 348         /*
 349          * If the commit is uninteresting, don't try to
 350          * prune parents - we want the maximal uninteresting
 351          * set.
 352          *
 353          * Normally we haven't parsed the parent
 354          * yet, so we won't have a parent of a parent
 355          * here. However, it may turn out that we've
 356          * reached this commit some other way (where it
 357          * wasn't uninteresting), in which case we need
 358          * to mark its parents recursively too..
 359          */
 360         if (commit->object.flags & UNINTERESTING) {
 361                 while (parent) {
 362                         struct commit *p = parent->item;
 363                         parent = parent->next;
 364                         parse_commit(p);
 365                         p->object.flags |= UNINTERESTING;
 366                         if (p->parents)
 367                                 mark_parents_uninteresting(p);
 368                         if (p->object.flags & SEEN)
 369                                 continue;
 370                         p->object.flags |= SEEN;
 371                         insert_by_date(p, list);
 372                 }
 373                 return;
 374         }
 375
 376         /*
 377          * Ok, the commit wasn't uninteresting. Try to
 378          * simplify the commit history and find the parent
 379          * that has no differences in the path set if one exists.
 380          */
 381         if (revs->prune_fn)
 382                 revs->prune_fn(revs, commit);
 383
 384         if (revs->no_walk)
 385                 return;
 386
 387         parent = commit->parents;
 388         while (parent) {
 389                 struct commit *p = parent->item;
 390
 391                 parent = parent->next;
 392
 393                 parse_commit(p);
 394                 if (p->object.flags & SEEN)
 395                         continue;
 396                 p->object.flags |= SEEN;
 397                 insert_by_date(p, list);
 398         }
 399 }
 400
 401 static void limit_list(struct rev_info *revs)
 402 {
 403         struct commit_list *list = revs->commits;
 404         struct commit_list *newlist = NULL;
 405         struct commit_list **p = &newlist;
 406
 407         while (list) {
 408                 struct commit_list *entry = list;
 409                 struct commit *commit = list->item;
 410                 struct object *obj = &commit->object;
 411
 412                 list = list->next;
 413                 free(entry);
 414
 415                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 416                         obj->flags |= UNINTERESTING;
 417                 if (revs->unpacked && has_sha1_pack(obj->sha1))
 418                         obj->flags |= UNINTERESTING;
 419                 add_parents_to_list(revs, commit, &list);
 420                 if (obj->flags & UNINTERESTING) {
 421                         mark_parents_uninteresting(commit);
 422                         if (everybody_uninteresting(list))
 423                                 break;
 424                         continue;
 425                 }
 426                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 427                         continue;
 428                 p = &commit_list_insert(commit, p)->next;
 429         }
 430         if (revs->boundary) {
 431                 /* mark the ones that are on the result list first */
 432                 for (list = newlist; list; list = list->next) {
 433                         struct commit *commit = list->item;
 434                         commit->object.flags |= TMP_MARK;
 435                 }
 436                 for (list = newlist; list; list = list->next) {
 437                         struct commit *commit = list->item;
 438                         struct object *obj = &commit->object;
 439                         struct commit_list *parent;
 440                         if (obj->flags & UNINTERESTING)
 441                                 continue;
 442                         for (parent = commit->parents;
 443                              parent;
 444                              parent = parent->next) {
 445                                 struct commit *pcommit = parent->item;
 446                                 if (!(pcommit->object.flags & UNINTERESTING))
 447                                         continue;
 448                                 pcommit->object.flags |= BOUNDARY;
 449                                 if (pcommit->object.flags & TMP_MARK)
 450                                         continue;
 451                                 pcommit->object.flags |= TMP_MARK;
 452                                 p = &commit_list_insert(pcommit, p)->next;
 453                         }
 454                 }
 455                 for (list = newlist; list; list = list->next) {
 456                         struct commit *commit = list->item;
 457                         commit->object.flags &= ~TMP_MARK;
 458                 }
 459         }
 460         revs->commits = newlist;
 461 }
 462
 463 static int all_flags;
 464 static struct rev_info *all_revs;
 465
 466 static int handle_one_ref(const char *path, const unsigned char *sha1)
 467 {
 468         struct object *object = get_reference(all_revs, path, sha1, all_flags);
 469         add_pending_object(all_revs, object, "");
 470         return 0;
 471 }
 472
 473 static void handle_all(struct rev_info *revs, unsigned flags)
 474 {
 475         all_revs = revs;
 476         all_flags = flags;
 477         for_each_ref(handle_one_ref);
 478 }
 479
 480 void init_revisions(struct rev_info *revs)
 481 {
 482         memset(revs, 0, sizeof(*revs));
 483
 484         revs->abbrev = DEFAULT_ABBREV;
 485         revs->ignore_merges = 1;
 486         revs->pruning.recursive = 1;
 487         revs->pruning.add_remove = file_add_remove;
 488         revs->pruning.change = file_change;
 489         revs->lifo = 1;
 490         revs->dense = 1;
 491         revs->prefix = setup_git_directory();
 492         revs->max_age = -1;
 493         revs->min_age = -1;
 494         revs->max_count = -1;
 495
 496         revs->prune_fn = NULL;
 497         revs->prune_data = NULL;
 498
 499         revs->topo_setter = topo_sort_default_setter;
 500         revs->topo_getter = topo_sort_default_getter;
 501
 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                                 continue;
 679                         }
 680                         if (!strncmp(arg, "--pretty", 8)) {
 681                                 revs->verbose_header = 1;
 682                                 revs->commit_format = get_commit_format(arg+8);
 683                                 continue;
 684                         }
 685                         if (!strcmp(arg, "--root")) {
 686                                 revs->show_root_diff = 1;
 687                                 continue;
 688                         }
 689                         if (!strcmp(arg, "--no-commit-id")) {
 690                                 revs->no_commit_id = 1;
 691                                 continue;
 692                         }
 693                         if (!strcmp(arg, "--always")) {
 694                                 revs->always_show_header = 1;
 695                                 continue;
 696                         }
 697                         if (!strcmp(arg, "--no-abbrev")) {
 698                                 revs->abbrev = 0;
 699                                 continue;
 700                         }
 701                         if (!strcmp(arg, "--abbrev")) {
 702                                 revs->abbrev = DEFAULT_ABBREV;
 703                                 continue;
 704                         }
 705                         if (!strcmp(arg, "--abbrev-commit")) {
 706                                 revs->abbrev_commit = 1;
 707                                 continue;
 708                         }
 709                         if (!strcmp(arg, "--full-diff")) {
 710                                 revs->diff = 1;
 711                                 revs->full_diff = 1;
 712                                 continue;
 713                         }
 714                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
 715                         if (opts > 0) {
 716                                 revs->diff = 1;
 717                                 i += opts - 1;
 718                                 continue;
 719                         }
 720                         *unrecognized++ = arg;
 721                         left++;
 722                         continue;
 723                 }
 724                 dotdot = strstr(arg, "..");
 725                 if (dotdot) {
 726                         unsigned char from_sha1[20];
 727                         const char *next = dotdot + 2;
 728                         const char *this = arg;
 729                         *dotdot = 0;
 730                         if (!*next)
 731                                 next = "HEAD";
 732                         if (dotdot == arg)
 733                                 this = "HEAD";
 734                         if (!get_sha1(this, from_sha1) &&
 735                             !get_sha1(next, sha1)) {
 736                                 struct object *exclude;
 737                                 struct object *include;
 738
 739                                 exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
 740                                 include = get_reference(revs, next, sha1, flags);
 741                                 if (!exclude || !include)
 742                                         die("Invalid revision range %s..%s", arg, next);
 743                                 add_pending_object(revs, exclude, this);
 744                                 add_pending_object(revs, include, next);
 745                                 continue;
 746                         }
 747                         *dotdot = '.';
 748                 }
 749                 local_flags = 0;
 750                 if (*arg == '^') {
 751                         local_flags = UNINTERESTING;
 752                         arg++;
 753                 }
 754                 if (get_sha1(arg, sha1) < 0) {
 755                         int j;
 756
 757                         if (seen_dashdash || local_flags)
 758                                 die("bad revision '%s'", arg);
 759
 760                         /* If we didn't have a "--", all filenames must exist */
 761                         for (j = i; j < argc; j++)
 762                                 verify_filename(revs->prefix, argv[j]);
 763
 764                         revs->prune_data = get_pathspec(revs->prefix, argv + i);
 765                         break;
 766                 }
 767                 object = get_reference(revs, arg, sha1, flags ^ local_flags);
 768                 add_pending_object(revs, object, arg);
 769         }
 770         if (def && !revs->pending_objects) {
 771                 unsigned char sha1[20];
 772                 struct object *object;
 773                 if (get_sha1(def, sha1) < 0)
 774                         die("bad default revision '%s'", def);
 775                 object = get_reference(revs, def, sha1, 0);
 776                 add_pending_object(revs, object, def);
 777         }
 778
 779         if (revs->topo_order || revs->unpacked)
 780                 revs->limited = 1;
 781
 782         if (revs->prune_data) {
 783                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
 784                 revs->prune_fn = try_to_simplify_commit;
 785                 if (!revs->full_diff)
 786                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
 787         }
 788         if (revs->combine_merges) {
 789                 revs->ignore_merges = 0;
 790                 if (revs->dense_combined_merges &&
 791                     (revs->diffopt.output_format != DIFF_FORMAT_DIFFSTAT))
 792                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 793         }
 794         revs->diffopt.abbrev = revs->abbrev;
 795         diff_setup_done(&revs->diffopt);
 796
 797         return left;
 798 }
 799
 800 void prepare_revision_walk(struct rev_info *revs)
 801 {
 802         struct object_list *list;
 803
 804         list = revs->pending_objects;
 805         revs->pending_objects = NULL;
 806         while (list) {
 807                 struct commit *commit = handle_commit(revs, list->item, list->name);
 808                 if (commit) {
 809                         if (!(commit->object.flags & SEEN)) {
 810                                 commit->object.flags |= SEEN;
 811                                 insert_by_date(commit, &revs->commits);
 812                         }
 813                 }
 814                 list = list->next;
 815         }
 816
 817         if (revs->no_walk)
 818                 return;
 819         if (revs->limited)
 820                 limit_list(revs);
 821         if (revs->topo_order)
 822                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
 823                                              revs->topo_setter,
 824                                              revs->topo_getter);
 825 }
 826
 827 static int rewrite_one(struct rev_info *revs, struct commit **pp)
 828 {
 829         for (;;) {
 830                 struct commit *p = *pp;
 831                 if (!revs->limited)
 832                         add_parents_to_list(revs, p, &revs->commits);
 833                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
 834                         return 0;
 835                 if (!p->parents)
 836                         return -1;
 837                 *pp = p->parents->item;
 838         }
 839 }
 840
 841 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
 842 {
 843         struct commit_list **pp = &commit->parents;
 844         while (*pp) {
 845                 struct commit_list *parent = *pp;
 846                 if (rewrite_one(revs, &parent->item) < 0) {
 847                         *pp = parent->next;
 848                         continue;
 849                 }
 850                 pp = &parent->next;
 851         }
 852 }
 853
 854 static void mark_boundary_to_show(struct commit *commit)
 855 {
 856         struct commit_list *p = commit->parents;
 857         while (p) {
 858                 commit = p->item;
 859                 p = p->next;
 860                 if (commit->object.flags & BOUNDARY)
 861                         commit->object.flags |= BOUNDARY_SHOW;
 862         }
 863 }
 864
 865 struct commit *get_revision(struct rev_info *revs)
 866 {
 867         struct commit_list *list = revs->commits;
 868
 869         if (!list)
 870                 return NULL;
 871
 872         /* Check the max_count ... */
 873         switch (revs->max_count) {
 874         case -1:
 875                 break;
 876         case 0:
 877                 return NULL;
 878         default:
 879                 revs->max_count--;
 880         }
 881
 882         do {
 883                 struct commit *commit = revs->commits->item;
 884
 885                 revs->commits = revs->commits->next;
 886
 887                 /*
 888                  * If we haven't done the list limiting, we need to look at
 889                  * the parents here. We also need to do the date-based limiting
 890                  * that we'd otherwise have done in limit_list().
 891                  */
 892                 if (!revs->limited) {
 893                         if ((revs->unpacked &&
 894                              has_sha1_pack(commit->object.sha1)) ||
 895                             (revs->max_age != -1 &&
 896                              (commit->date < revs->max_age)))
 897                                 continue;
 898                         add_parents_to_list(revs, commit, &revs->commits);
 899                 }
 900                 if (commit->object.flags & SHOWN)
 901                         continue;
 902
 903                 /* We want to show boundary commits only when their
 904                  * children are shown.  When path-limiter is in effect,
 905                  * rewrite_parents() drops some commits from getting shown,
 906                  * and there is no point showing boundary parents that
 907                  * are not shown.  After rewrite_parents() rewrites the
 908                  * parents of a commit that is shown, we mark the boundary
 909                  * parents with BOUNDARY_SHOW.
 910                  */
 911                 if (commit->object.flags & BOUNDARY_SHOW) {
 912                         commit->object.flags |= SHOWN;
 913                         return commit;
 914                 }
 915                 if (commit->object.flags & UNINTERESTING)
 916                         continue;
 917                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 918                         continue;
 919                 if (revs->no_merges &&
 920                     commit->parents && commit->parents->next)
 921                         continue;
 922                 if (revs->prune_fn && revs->dense) {
 923                         if (!(commit->object.flags & TREECHANGE))
 924                                 continue;
 925                         if (revs->parents)
 926                                 rewrite_parents(revs, commit);
 927                 }
 928                 if (revs->boundary)
 929                         mark_boundary_to_show(commit);
 930                 commit->object.flags |= SHOWN;
 931                 return commit;
 932         } while (revs->commits);
 933         return NULL;
 934 }