revision.con commit Documentation: revise top of git man page (23091e9)
   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
  10static 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
  34struct 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
  47static void mark_blob_uninteresting(struct blob *blob)
  48{
  49        if (blob->object.flags & UNINTERESTING)
  50                return;
  51        blob->object.flags |= UNINTERESTING;
  52}
  53
  54void 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
  79void 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
 114static 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
 119static struct commit *get_commit_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
 127        /*
 128         * Tag object? Look what it points to..
 129         */
 130        while (object->type == tag_type) {
 131                struct tag *tag = (struct tag *) object;
 132                object->flags |= flags;
 133                if (revs->tag_objects && !(object->flags & UNINTERESTING))
 134                        add_pending_object(revs, object, tag->tag);
 135                object = parse_object(tag->tagged->sha1);
 136                if (!object)
 137                        die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 138        }
 139
 140        /*
 141         * Commit object? Just return it, we'll do all the complex
 142         * reachability crud.
 143         */
 144        if (object->type == commit_type) {
 145                struct commit *commit = (struct commit *)object;
 146                object->flags |= flags;
 147                if (parse_commit(commit) < 0)
 148                        die("unable to parse commit %s", name);
 149                if (flags & UNINTERESTING) {
 150                        mark_parents_uninteresting(commit);
 151                        revs->limited = 1;
 152                }
 153                return commit;
 154        }
 155
 156        /*
 157         * Tree object? Either mark it uniniteresting, or add it
 158         * to the list of objects to look at later..
 159         */
 160        if (object->type == tree_type) {
 161                struct tree *tree = (struct tree *)object;
 162                if (!revs->tree_objects)
 163                        return NULL;
 164                if (flags & UNINTERESTING) {
 165                        mark_tree_uninteresting(tree);
 166                        return NULL;
 167                }
 168                add_pending_object(revs, object, "");
 169                return NULL;
 170        }
 171
 172        /*
 173         * Blob object? You know the drill by now..
 174         */
 175        if (object->type == blob_type) {
 176                struct blob *blob = (struct blob *)object;
 177                if (!revs->blob_objects)
 178                        return NULL;
 179                if (flags & UNINTERESTING) {
 180                        mark_blob_uninteresting(blob);
 181                        return NULL;
 182                }
 183                add_pending_object(revs, object, "");
 184                return NULL;
 185        }
 186        die("%s is unknown object", name);
 187}
 188
 189static int everybody_uninteresting(struct commit_list *orig)
 190{
 191        struct commit_list *list = orig;
 192        while (list) {
 193                struct commit *commit = list->item;
 194                list = list->next;
 195                if (commit->object.flags & UNINTERESTING)
 196                        continue;
 197                return 0;
 198        }
 199        return 1;
 200}
 201
 202static int tree_difference = REV_TREE_SAME;
 203
 204static void file_add_remove(struct diff_options *options,
 205                    int addremove, unsigned mode,
 206                    const unsigned char *sha1,
 207                    const char *base, const char *path)
 208{
 209        int diff = REV_TREE_DIFFERENT;
 210
 211        /*
 212         * Is it an add of a new file? It means that the old tree
 213         * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 214         * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 215         * (and if it already was "REV_TREE_NEW", we'll keep it
 216         * "REV_TREE_NEW" of course).
 217         */
 218        if (addremove == '+') {
 219                diff = tree_difference;
 220                if (diff != REV_TREE_SAME)
 221                        return;
 222                diff = REV_TREE_NEW;
 223        }
 224        tree_difference = diff;
 225}
 226
 227static void file_change(struct diff_options *options,
 228                 unsigned old_mode, unsigned new_mode,
 229                 const unsigned char *old_sha1,
 230                 const unsigned char *new_sha1,
 231                 const char *base, const char *path)
 232{
 233        tree_difference = REV_TREE_DIFFERENT;
 234}
 235
 236static struct diff_options diff_opt = {
 237        .recursive = 1,
 238        .add_remove = file_add_remove,
 239        .change = file_change,
 240};
 241
 242int rev_compare_tree(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, "", &diff_opt) < 0)
 250                return REV_TREE_DIFFERENT;
 251        return tree_difference;
 252}
 253
 254int rev_same_tree_as_empty(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", &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, "", &diff_opt);
 273        free(tree);
 274
 275        return retval >= 0 && !tree_difference;
 276}
 277
 278static 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(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(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(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
 339static 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        /*
 344         * If the commit is uninteresting, don't try to
 345         * prune parents - we want the maximal uninteresting
 346         * set.
 347         *
 348         * Normally we haven't parsed the parent
 349         * yet, so we won't have a parent of a parent
 350         * here. However, it may turn out that we've
 351         * reached this commit some other way (where it
 352         * wasn't uninteresting), in which case we need
 353         * to mark its parents recursively too..
 354         */
 355        if (commit->object.flags & UNINTERESTING) {
 356                while (parent) {
 357                        struct commit *p = parent->item;
 358                        parent = parent->next;
 359                        parse_commit(p);
 360                        p->object.flags |= UNINTERESTING;
 361                        if (p->parents)
 362                                mark_parents_uninteresting(p);
 363                        if (p->object.flags & SEEN)
 364                                continue;
 365                        p->object.flags |= SEEN;
 366                        insert_by_date(p, list);
 367                }
 368                return;
 369        }
 370
 371        /*
 372         * Ok, the commit wasn't uninteresting. Try to
 373         * simplify the commit history and find the parent
 374         * that has no differences in the path set if one exists.
 375         */
 376        if (revs->prune_fn)
 377                revs->prune_fn(revs, commit);
 378
 379        parent = commit->parents;
 380        while (parent) {
 381                struct commit *p = parent->item;
 382
 383                parent = parent->next;
 384
 385                parse_commit(p);
 386                if (p->object.flags & SEEN)
 387                        continue;
 388                p->object.flags |= SEEN;
 389                insert_by_date(p, list);
 390        }
 391}
 392
 393static void limit_list(struct rev_info *revs)
 394{
 395        struct commit_list *list = revs->commits;
 396        struct commit_list *newlist = NULL;
 397        struct commit_list **p = &newlist;
 398
 399        while (list) {
 400                struct commit_list *entry = list;
 401                struct commit *commit = list->item;
 402                struct object *obj = &commit->object;
 403
 404                list = list->next;
 405                free(entry);
 406
 407                if (revs->max_age != -1 && (commit->date < revs->max_age))
 408                        obj->flags |= UNINTERESTING;
 409                if (revs->unpacked && has_sha1_pack(obj->sha1))
 410                        obj->flags |= UNINTERESTING;
 411                add_parents_to_list(revs, commit, &list);
 412                if (obj->flags & UNINTERESTING) {
 413                        mark_parents_uninteresting(commit);
 414                        if (everybody_uninteresting(list))
 415                                break;
 416                        continue;
 417                }
 418                if (revs->min_age != -1 && (commit->date > revs->min_age))
 419                        continue;
 420                p = &commit_list_insert(commit, p)->next;
 421        }
 422        if (revs->boundary) {
 423                /* mark the ones that are on the result list first */
 424                for (list = newlist; list; list = list->next) {
 425                        struct commit *commit = list->item;
 426                        commit->object.flags |= TMP_MARK;
 427                }
 428                for (list = newlist; list; list = list->next) {
 429                        struct commit *commit = list->item;
 430                        struct object *obj = &commit->object;
 431                        struct commit_list *parent;
 432                        if (obj->flags & UNINTERESTING)
 433                                continue;
 434                        for (parent = commit->parents;
 435                             parent;
 436                             parent = parent->next) {
 437                                struct commit *pcommit = parent->item;
 438                                if (!(pcommit->object.flags & UNINTERESTING))
 439                                        continue;
 440                                pcommit->object.flags |= BOUNDARY;
 441                                if (pcommit->object.flags & TMP_MARK)
 442                                        continue;
 443                                pcommit->object.flags |= TMP_MARK;
 444                                p = &commit_list_insert(pcommit, p)->next;
 445                        }
 446                }
 447                for (list = newlist; list; list = list->next) {
 448                        struct commit *commit = list->item;
 449                        commit->object.flags &= ~TMP_MARK;
 450                }
 451        }
 452        revs->commits = newlist;
 453}
 454
 455static void add_one_commit(struct commit *commit, struct rev_info *revs)
 456{
 457        if (!commit || (commit->object.flags & SEEN))
 458                return;
 459        commit->object.flags |= SEEN;
 460        commit_list_insert(commit, &revs->commits);
 461}
 462
 463static int all_flags;
 464static struct rev_info *all_revs;
 465
 466static int handle_one_ref(const char *path, const unsigned char *sha1)
 467{
 468        struct commit *commit = get_commit_reference(all_revs, path, sha1, all_flags);
 469        add_one_commit(commit, all_revs);
 470        return 0;
 471}
 472
 473static 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
 480void init_revisions(struct rev_info *revs)
 481{
 482        memset(revs, 0, sizeof(*revs));
 483        revs->lifo = 1;
 484        revs->dense = 1;
 485        revs->prefix = setup_git_directory();
 486        revs->max_age = -1;
 487        revs->min_age = -1;
 488        revs->max_count = -1;
 489
 490        revs->prune_fn = NULL;
 491        revs->prune_data = NULL;
 492
 493        revs->topo_setter = topo_sort_default_setter;
 494        revs->topo_getter = topo_sort_default_getter;
 495}
 496
 497/*
 498 * Parse revision information, filling in the "rev_info" structure,
 499 * and removing the used arguments from the argument list.
 500 *
 501 * Returns the number of arguments left that weren't recognized
 502 * (which are also moved to the head of the argument list)
 503 */
 504int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 505{
 506        int i, flags, seen_dashdash;
 507        const char **unrecognized = argv + 1;
 508        int left = 1;
 509
 510        init_revisions(revs);
 511
 512        /* First, search for "--" */
 513        seen_dashdash = 0;
 514        for (i = 1; i < argc; i++) {
 515                const char *arg = argv[i];
 516                if (strcmp(arg, "--"))
 517                        continue;
 518                argv[i] = NULL;
 519                argc = i;
 520                revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 521                seen_dashdash = 1;
 522                break;
 523        }
 524
 525        flags = 0;
 526        for (i = 1; i < argc; i++) {
 527                struct commit *commit;
 528                const char *arg = argv[i];
 529                unsigned char sha1[20];
 530                char *dotdot;
 531                int local_flags;
 532
 533                if (*arg == '-') {
 534                        if (!strncmp(arg, "--max-count=", 12)) {
 535                                revs->max_count = atoi(arg + 12);
 536                                continue;
 537                        }
 538                        /* accept -<digit>, like traditilnal "head" */
 539                        if ((*arg == '-') && isdigit(arg[1])) {
 540                                revs->max_count = atoi(arg + 1);
 541                                continue;
 542                        }
 543                        if (!strcmp(arg, "-n")) {
 544                                if (argc <= i + 1)
 545                                        die("-n requires an argument");
 546                                revs->max_count = atoi(argv[++i]);
 547                                continue;
 548                        }
 549                        if (!strncmp(arg,"-n",2)) {
 550                                revs->max_count = atoi(arg + 2);
 551                                continue;
 552                        }
 553                        if (!strncmp(arg, "--max-age=", 10)) {
 554                                revs->max_age = atoi(arg + 10);
 555                                continue;
 556                        }
 557                        if (!strncmp(arg, "--since=", 8)) {
 558                                revs->max_age = approxidate(arg + 8);
 559                                continue;
 560                        }
 561                        if (!strncmp(arg, "--after=", 8)) {
 562                                revs->max_age = approxidate(arg + 8);
 563                                continue;
 564                        }
 565                        if (!strncmp(arg, "--min-age=", 10)) {
 566                                revs->min_age = atoi(arg + 10);
 567                                continue;
 568                        }
 569                        if (!strncmp(arg, "--before=", 9)) {
 570                                revs->min_age = approxidate(arg + 9);
 571                                continue;
 572                        }
 573                        if (!strncmp(arg, "--until=", 8)) {
 574                                revs->min_age = approxidate(arg + 8);
 575                                continue;
 576                        }
 577                        if (!strcmp(arg, "--all")) {
 578                                handle_all(revs, flags);
 579                                continue;
 580                        }
 581                        if (!strcmp(arg, "--not")) {
 582                                flags ^= UNINTERESTING;
 583                                continue;
 584                        }
 585                        if (!strcmp(arg, "--default")) {
 586                                if (++i >= argc)
 587                                        die("bad --default argument");
 588                                def = argv[i];
 589                                continue;
 590                        }
 591                        if (!strcmp(arg, "--topo-order")) {
 592                                revs->topo_order = 1;
 593                                continue;
 594                        }
 595                        if (!strcmp(arg, "--date-order")) {
 596                                revs->lifo = 0;
 597                                revs->topo_order = 1;
 598                                continue;
 599                        }
 600                        if (!strcmp(arg, "--parents")) {
 601                                revs->parents = 1;
 602                                continue;
 603                        }
 604                        if (!strcmp(arg, "--dense")) {
 605                                revs->dense = 1;
 606                                continue;
 607                        }
 608                        if (!strcmp(arg, "--sparse")) {
 609                                revs->dense = 0;
 610                                continue;
 611                        }
 612                        if (!strcmp(arg, "--remove-empty")) {
 613                                revs->remove_empty_trees = 1;
 614                                continue;
 615                        }
 616                        if (!strcmp(arg, "--no-merges")) {
 617                                revs->no_merges = 1;
 618                                continue;
 619                        }
 620                        if (!strcmp(arg, "--boundary")) {
 621                                revs->boundary = 1;
 622                                continue;
 623                        }
 624                        if (!strcmp(arg, "--objects")) {
 625                                revs->tag_objects = 1;
 626                                revs->tree_objects = 1;
 627                                revs->blob_objects = 1;
 628                                continue;
 629                        }
 630                        if (!strcmp(arg, "--objects-edge")) {
 631                                revs->tag_objects = 1;
 632                                revs->tree_objects = 1;
 633                                revs->blob_objects = 1;
 634                                revs->edge_hint = 1;
 635                                continue;
 636                        }
 637                        if (!strcmp(arg, "--unpacked")) {
 638                                revs->unpacked = 1;
 639                                continue;
 640                        }
 641                        *unrecognized++ = arg;
 642                        left++;
 643                        continue;
 644                }
 645                dotdot = strstr(arg, "..");
 646                if (dotdot) {
 647                        unsigned char from_sha1[20];
 648                        const char *next = dotdot + 2;
 649                        const char *this = arg;
 650                        *dotdot = 0;
 651                        if (!*next)
 652                                next = "HEAD";
 653                        if (dotdot == arg)
 654                                this = "HEAD";
 655                        if (!get_sha1(this, from_sha1) &&
 656                            !get_sha1(next, sha1)) {
 657                                struct commit *exclude;
 658                                struct commit *include;
 659
 660                                exclude = get_commit_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
 661                                include = get_commit_reference(revs, next, sha1, flags);
 662                                if (!exclude || !include)
 663                                        die("Invalid revision range %s..%s", arg, next);
 664                                add_one_commit(exclude, revs);
 665                                add_one_commit(include, revs);
 666                                continue;
 667                        }
 668                        *dotdot = '.';
 669                }
 670                local_flags = 0;
 671                if (*arg == '^') {
 672                        local_flags = UNINTERESTING;
 673                        arg++;
 674                }
 675                if (get_sha1(arg, sha1) < 0) {
 676                        struct stat st;
 677                        int j;
 678
 679                        if (seen_dashdash || local_flags)
 680                                die("bad revision '%s'", arg);
 681
 682                        /* If we didn't have a "--", all filenames must exist */
 683                        for (j = i; j < argc; j++) {
 684                                if (lstat(argv[j], &st) < 0)
 685                                        die("'%s': %s", argv[j], strerror(errno));
 686                        }
 687                        revs->prune_data = get_pathspec(revs->prefix, argv + i);
 688                        break;
 689                }
 690                commit = get_commit_reference(revs, arg, sha1, flags ^ local_flags);
 691                add_one_commit(commit, revs);
 692        }
 693        if (def && !revs->commits) {
 694                unsigned char sha1[20];
 695                struct commit *commit;
 696                if (get_sha1(def, sha1) < 0)
 697                        die("bad default revision '%s'", def);
 698                commit = get_commit_reference(revs, def, sha1, 0);
 699                add_one_commit(commit, revs);
 700        }
 701
 702        if (revs->topo_order || revs->unpacked)
 703                revs->limited = 1;
 704
 705        if (revs->prune_data) {
 706                diff_tree_setup_paths(revs->prune_data);
 707                revs->prune_fn = try_to_simplify_commit;
 708
 709                /*
 710                 * If we fix up parent data, we currently cannot
 711                 * do that on-the-fly.
 712                 */
 713                if (revs->parents)
 714                        revs->limited = 1;
 715        }
 716
 717        return left;
 718}
 719
 720void prepare_revision_walk(struct rev_info *revs)
 721{
 722        sort_by_date(&revs->commits);
 723        if (revs->limited)
 724                limit_list(revs);
 725        if (revs->topo_order)
 726                sort_in_topological_order_fn(&revs->commits, revs->lifo,
 727                                             revs->topo_setter,
 728                                             revs->topo_getter);
 729}
 730
 731static int rewrite_one(struct commit **pp)
 732{
 733        for (;;) {
 734                struct commit *p = *pp;
 735                if (p->object.flags & (TREECHANGE | UNINTERESTING))
 736                        return 0;
 737                if (!p->parents)
 738                        return -1;
 739                *pp = p->parents->item;
 740        }
 741}
 742
 743static void rewrite_parents(struct commit *commit)
 744{
 745        struct commit_list **pp = &commit->parents;
 746        while (*pp) {
 747                struct commit_list *parent = *pp;
 748                if (rewrite_one(&parent->item) < 0) {
 749                        *pp = parent->next;
 750                        continue;
 751                }
 752                pp = &parent->next;
 753        }
 754}
 755
 756struct commit *get_revision(struct rev_info *revs)
 757{
 758        struct commit_list *list = revs->commits;
 759
 760        if (!list)
 761                return NULL;
 762
 763        /* Check the max_count ... */
 764        switch (revs->max_count) {
 765        case -1:
 766                break;
 767        case 0:
 768                return NULL;
 769        default:
 770                revs->max_count--;
 771        }
 772
 773        do {
 774                struct commit *commit = revs->commits->item;
 775
 776                revs->commits = revs->commits->next;
 777
 778                /*
 779                 * If we haven't done the list limiting, we need to look at
 780                 * the parents here. We also need to do the date-based limiting
 781                 * that we'd otherwise have done in limit_list().
 782                 */
 783                if (!revs->limited) {
 784                        if ((revs->unpacked &&
 785                             has_sha1_pack(commit->object.sha1)) ||
 786                            (revs->max_age != -1 &&
 787                             (commit->date < revs->max_age)))
 788                                continue;
 789                        add_parents_to_list(revs, commit, &revs->commits);
 790                }
 791                if (commit->object.flags & SHOWN)
 792                        continue;
 793                if (!(commit->object.flags & BOUNDARY) &&
 794                    (commit->object.flags & UNINTERESTING))
 795                        continue;
 796                if (revs->min_age != -1 && (commit->date > revs->min_age))
 797                        continue;
 798                if (revs->no_merges &&
 799                    commit->parents && commit->parents->next)
 800                        continue;
 801                if (revs->prune_fn && revs->dense) {
 802                        if (!(commit->object.flags & TREECHANGE))
 803                                continue;
 804                        if (revs->parents)
 805                                rewrite_parents(commit);
 806                }
 807                commit->object.flags |= SHOWN;
 808                return commit;
 809        } while (revs->commits);
 810        return NULL;
 811}