shallow.con commit preparing for 2.10.3 (c3808ca)
   1#include "cache.h"
   2#include "tempfile.h"
   3#include "lockfile.h"
   4#include "commit.h"
   5#include "tag.h"
   6#include "pkt-line.h"
   7#include "remote.h"
   8#include "refs.h"
   9#include "sha1-array.h"
  10#include "diff.h"
  11#include "revision.h"
  12#include "commit-slab.h"
  13
  14static int is_shallow = -1;
  15static struct stat_validity shallow_stat;
  16static char *alternate_shallow_file;
  17
  18void set_alternate_shallow_file(const char *path, int override)
  19{
  20        if (is_shallow != -1)
  21                die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
  22        if (alternate_shallow_file && !override)
  23                return;
  24        free(alternate_shallow_file);
  25        alternate_shallow_file = xstrdup_or_null(path);
  26}
  27
  28int register_shallow(const unsigned char *sha1)
  29{
  30        struct commit_graft *graft =
  31                xmalloc(sizeof(struct commit_graft));
  32        struct commit *commit = lookup_commit(sha1);
  33
  34        hashcpy(graft->oid.hash, sha1);
  35        graft->nr_parent = -1;
  36        if (commit && commit->object.parsed)
  37                commit->parents = NULL;
  38        return register_commit_graft(graft, 0);
  39}
  40
  41int is_repository_shallow(void)
  42{
  43        FILE *fp;
  44        char buf[1024];
  45        const char *path = alternate_shallow_file;
  46
  47        if (is_shallow >= 0)
  48                return is_shallow;
  49
  50        if (!path)
  51                path = git_path_shallow();
  52        /*
  53         * fetch-pack sets '--shallow-file ""' as an indicator that no
  54         * shallow file should be used. We could just open it and it
  55         * will likely fail. But let's do an explicit check instead.
  56         */
  57        if (!*path || (fp = fopen(path, "r")) == NULL) {
  58                stat_validity_clear(&shallow_stat);
  59                is_shallow = 0;
  60                return is_shallow;
  61        }
  62        stat_validity_update(&shallow_stat, fileno(fp));
  63        is_shallow = 1;
  64
  65        while (fgets(buf, sizeof(buf), fp)) {
  66                unsigned char sha1[20];
  67                if (get_sha1_hex(buf, sha1))
  68                        die("bad shallow line: %s", buf);
  69                register_shallow(sha1);
  70        }
  71        fclose(fp);
  72        return is_shallow;
  73}
  74
  75struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
  76                int shallow_flag, int not_shallow_flag)
  77{
  78        int i = 0, cur_depth = 0;
  79        struct commit_list *result = NULL;
  80        struct object_array stack = OBJECT_ARRAY_INIT;
  81        struct commit *commit = NULL;
  82        struct commit_graft *graft;
  83
  84        while (commit || i < heads->nr || stack.nr) {
  85                struct commit_list *p;
  86                if (!commit) {
  87                        if (i < heads->nr) {
  88                                commit = (struct commit *)
  89                                        deref_tag(heads->objects[i++].item, NULL, 0);
  90                                if (!commit || commit->object.type != OBJ_COMMIT) {
  91                                        commit = NULL;
  92                                        continue;
  93                                }
  94                                if (!commit->util)
  95                                        commit->util = xmalloc(sizeof(int));
  96                                *(int *)commit->util = 0;
  97                                cur_depth = 0;
  98                        } else {
  99                                commit = (struct commit *)
 100                                        stack.objects[--stack.nr].item;
 101                                cur_depth = *(int *)commit->util;
 102                        }
 103                }
 104                parse_commit_or_die(commit);
 105                cur_depth++;
 106                if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 107                    (is_repository_shallow() && !commit->parents &&
 108                     (graft = lookup_commit_graft(commit->object.oid.hash)) != NULL &&
 109                     graft->nr_parent < 0)) {
 110                        commit_list_insert(commit, &result);
 111                        commit->object.flags |= shallow_flag;
 112                        commit = NULL;
 113                        continue;
 114                }
 115                commit->object.flags |= not_shallow_flag;
 116                for (p = commit->parents, commit = NULL; p; p = p->next) {
 117                        if (!p->item->util) {
 118                                int *pointer = xmalloc(sizeof(int));
 119                                p->item->util = pointer;
 120                                *pointer =  cur_depth;
 121                        } else {
 122                                int *pointer = p->item->util;
 123                                if (cur_depth >= *pointer)
 124                                        continue;
 125                                *pointer = cur_depth;
 126                        }
 127                        if (p->next)
 128                                add_object_array(&p->item->object,
 129                                                NULL, &stack);
 130                        else {
 131                                commit = p->item;
 132                                cur_depth = *(int *)commit->util;
 133                        }
 134                }
 135        }
 136
 137        return result;
 138}
 139
 140static void check_shallow_file_for_update(void)
 141{
 142        if (is_shallow == -1)
 143                die("BUG: shallow must be initialized by now");
 144
 145        if (!stat_validity_check(&shallow_stat, git_path_shallow()))
 146                die("shallow file has changed since we read it");
 147}
 148
 149#define SEEN_ONLY 1
 150#define VERBOSE   2
 151
 152struct write_shallow_data {
 153        struct strbuf *out;
 154        int use_pack_protocol;
 155        int count;
 156        unsigned flags;
 157};
 158
 159static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 160{
 161        struct write_shallow_data *data = cb_data;
 162        const char *hex = oid_to_hex(&graft->oid);
 163        if (graft->nr_parent != -1)
 164                return 0;
 165        if (data->flags & SEEN_ONLY) {
 166                struct commit *c = lookup_commit(graft->oid.hash);
 167                if (!c || !(c->object.flags & SEEN)) {
 168                        if (data->flags & VERBOSE)
 169                                printf("Removing %s from .git/shallow\n",
 170                                       oid_to_hex(&c->object.oid));
 171                        return 0;
 172                }
 173        }
 174        data->count++;
 175        if (data->use_pack_protocol)
 176                packet_buf_write(data->out, "shallow %s", hex);
 177        else {
 178                strbuf_addstr(data->out, hex);
 179                strbuf_addch(data->out, '\n');
 180        }
 181        return 0;
 182}
 183
 184static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 185                                   const struct sha1_array *extra,
 186                                   unsigned flags)
 187{
 188        struct write_shallow_data data;
 189        int i;
 190        data.out = out;
 191        data.use_pack_protocol = use_pack_protocol;
 192        data.count = 0;
 193        data.flags = flags;
 194        for_each_commit_graft(write_one_shallow, &data);
 195        if (!extra)
 196                return data.count;
 197        for (i = 0; i < extra->nr; i++) {
 198                strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
 199                strbuf_addch(out, '\n');
 200                data.count++;
 201        }
 202        return data.count;
 203}
 204
 205int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 206                          const struct sha1_array *extra)
 207{
 208        return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 209}
 210
 211static struct tempfile temporary_shallow;
 212
 213const char *setup_temporary_shallow(const struct sha1_array *extra)
 214{
 215        struct strbuf sb = STRBUF_INIT;
 216        int fd;
 217
 218        if (write_shallow_commits(&sb, 0, extra)) {
 219                fd = xmks_tempfile(&temporary_shallow, git_path("shallow_XXXXXX"));
 220
 221                if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 222                        die_errno("failed to write to %s",
 223                                  get_tempfile_path(&temporary_shallow));
 224                close_tempfile(&temporary_shallow);
 225                strbuf_release(&sb);
 226                return get_tempfile_path(&temporary_shallow);
 227        }
 228        /*
 229         * is_repository_shallow() sees empty string as "no shallow
 230         * file".
 231         */
 232        return get_tempfile_path(&temporary_shallow);
 233}
 234
 235void setup_alternate_shallow(struct lock_file *shallow_lock,
 236                             const char **alternate_shallow_file,
 237                             const struct sha1_array *extra)
 238{
 239        struct strbuf sb = STRBUF_INIT;
 240        int fd;
 241
 242        fd = hold_lock_file_for_update(shallow_lock, git_path_shallow(),
 243                                       LOCK_DIE_ON_ERROR);
 244        check_shallow_file_for_update();
 245        if (write_shallow_commits(&sb, 0, extra)) {
 246                if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 247                        die_errno("failed to write to %s",
 248                                  get_lock_file_path(shallow_lock));
 249                *alternate_shallow_file = get_lock_file_path(shallow_lock);
 250        } else
 251                /*
 252                 * is_repository_shallow() sees empty string as "no
 253                 * shallow file".
 254                 */
 255                *alternate_shallow_file = "";
 256        strbuf_release(&sb);
 257}
 258
 259static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 260{
 261        int fd = *(int *)cb;
 262        if (graft->nr_parent == -1)
 263                packet_write(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 264        return 0;
 265}
 266
 267void advertise_shallow_grafts(int fd)
 268{
 269        if (!is_repository_shallow())
 270                return;
 271        for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 272}
 273
 274/*
 275 * mark_reachable_objects() should have been run prior to this and all
 276 * reachable commits marked as "SEEN".
 277 */
 278void prune_shallow(int show_only)
 279{
 280        static struct lock_file shallow_lock;
 281        struct strbuf sb = STRBUF_INIT;
 282        int fd;
 283
 284        if (show_only) {
 285                write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
 286                strbuf_release(&sb);
 287                return;
 288        }
 289        fd = hold_lock_file_for_update(&shallow_lock, git_path_shallow(),
 290                                       LOCK_DIE_ON_ERROR);
 291        check_shallow_file_for_update();
 292        if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
 293                if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 294                        die_errno("failed to write to %s",
 295                                  get_lock_file_path(&shallow_lock));
 296                commit_lock_file(&shallow_lock);
 297        } else {
 298                unlink(git_path_shallow());
 299                rollback_lock_file(&shallow_lock);
 300        }
 301        strbuf_release(&sb);
 302}
 303
 304struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 305
 306/*
 307 * Step 1, split sender shallow commits into "ours" and "theirs"
 308 * Step 2, clean "ours" based on .git/shallow
 309 */
 310void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
 311{
 312        int i;
 313        trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 314        memset(info, 0, sizeof(*info));
 315        info->shallow = sa;
 316        if (!sa)
 317                return;
 318        ALLOC_ARRAY(info->ours, sa->nr);
 319        ALLOC_ARRAY(info->theirs, sa->nr);
 320        for (i = 0; i < sa->nr; i++) {
 321                if (has_sha1_file(sa->sha1[i])) {
 322                        struct commit_graft *graft;
 323                        graft = lookup_commit_graft(sa->sha1[i]);
 324                        if (graft && graft->nr_parent < 0)
 325                                continue;
 326                        info->ours[info->nr_ours++] = i;
 327                } else
 328                        info->theirs[info->nr_theirs++] = i;
 329        }
 330}
 331
 332void clear_shallow_info(struct shallow_info *info)
 333{
 334        free(info->ours);
 335        free(info->theirs);
 336}
 337
 338/* Step 4, remove non-existent ones in "theirs" after getting the pack */
 339
 340void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 341{
 342        unsigned char (*sha1)[20] = info->shallow->sha1;
 343        int i, dst;
 344        trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 345        for (i = dst = 0; i < info->nr_theirs; i++) {
 346                if (i != dst)
 347                        info->theirs[dst] = info->theirs[i];
 348                if (has_sha1_file(sha1[info->theirs[i]]))
 349                        dst++;
 350        }
 351        info->nr_theirs = dst;
 352}
 353
 354define_commit_slab(ref_bitmap, uint32_t *);
 355
 356struct paint_info {
 357        struct ref_bitmap ref_bitmap;
 358        unsigned nr_bits;
 359        char **slab;
 360        char *free, *end;
 361        unsigned slab_count;
 362};
 363
 364static uint32_t *paint_alloc(struct paint_info *info)
 365{
 366        unsigned nr = (info->nr_bits + 31) / 32;
 367        unsigned size = nr * sizeof(uint32_t);
 368        void *p;
 369        if (!info->slab_count || info->free + size > info->end) {
 370                info->slab_count++;
 371                REALLOC_ARRAY(info->slab, info->slab_count);
 372                info->free = xmalloc(COMMIT_SLAB_SIZE);
 373                info->slab[info->slab_count - 1] = info->free;
 374                info->end = info->free + COMMIT_SLAB_SIZE;
 375        }
 376        p = info->free;
 377        info->free += size;
 378        return p;
 379}
 380
 381/*
 382 * Given a commit SHA-1, walk down to parents until either SEEN,
 383 * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 384 * all walked commits.
 385 */
 386static void paint_down(struct paint_info *info, const unsigned char *sha1,
 387                       int id)
 388{
 389        unsigned int i, nr;
 390        struct commit_list *head = NULL;
 391        int bitmap_nr = (info->nr_bits + 31) / 32;
 392        size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
 393        uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
 394        uint32_t *bitmap = paint_alloc(info);
 395        struct commit *c = lookup_commit_reference_gently(sha1, 1);
 396        if (!c)
 397                return;
 398        memset(bitmap, 0, bitmap_size);
 399        bitmap[id / 32] |= (1 << (id % 32));
 400        commit_list_insert(c, &head);
 401        while (head) {
 402                struct commit_list *p;
 403                struct commit *c = pop_commit(&head);
 404                uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 405
 406                /* XXX check "UNINTERESTING" from pack bitmaps if available */
 407                if (c->object.flags & (SEEN | UNINTERESTING))
 408                        continue;
 409                else
 410                        c->object.flags |= SEEN;
 411
 412                if (*refs == NULL)
 413                        *refs = bitmap;
 414                else {
 415                        memcpy(tmp, *refs, bitmap_size);
 416                        for (i = 0; i < bitmap_nr; i++)
 417                                tmp[i] |= bitmap[i];
 418                        if (memcmp(tmp, *refs, bitmap_size)) {
 419                                *refs = paint_alloc(info);
 420                                memcpy(*refs, tmp, bitmap_size);
 421                        }
 422                }
 423
 424                if (c->object.flags & BOTTOM)
 425                        continue;
 426
 427                if (parse_commit(c))
 428                        die("unable to parse commit %s",
 429                            oid_to_hex(&c->object.oid));
 430
 431                for (p = c->parents; p; p = p->next) {
 432                        uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
 433                                                          p->item);
 434                        if (p->item->object.flags & SEEN)
 435                                continue;
 436                        if (*p_refs == NULL || *p_refs == *refs)
 437                                *p_refs = *refs;
 438                        commit_list_insert(p->item, &head);
 439                }
 440        }
 441
 442        nr = get_max_object_index();
 443        for (i = 0; i < nr; i++) {
 444                struct object *o = get_indexed_object(i);
 445                if (o && o->type == OBJ_COMMIT)
 446                        o->flags &= ~SEEN;
 447        }
 448
 449        free(tmp);
 450}
 451
 452static int mark_uninteresting(const char *refname, const struct object_id *oid,
 453                              int flags, void *cb_data)
 454{
 455        struct commit *commit = lookup_commit_reference_gently(oid->hash, 1);
 456        if (!commit)
 457                return 0;
 458        commit->object.flags |= UNINTERESTING;
 459        mark_parents_uninteresting(commit);
 460        return 0;
 461}
 462
 463static void post_assign_shallow(struct shallow_info *info,
 464                                struct ref_bitmap *ref_bitmap,
 465                                int *ref_status);
 466/*
 467 * Step 6(+7), associate shallow commits with new refs
 468 *
 469 * info->ref must be initialized before calling this function.
 470 *
 471 * If used is not NULL, it's an array of info->shallow->nr
 472 * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 473 * m-th shallow commit from info->shallow.
 474 *
 475 * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 476 * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 477 * the ref needs some shallow commits from either info->ours or
 478 * info->theirs.
 479 */
 480void assign_shallow_commits_to_refs(struct shallow_info *info,
 481                                    uint32_t **used, int *ref_status)
 482{
 483        unsigned char (*sha1)[20] = info->shallow->sha1;
 484        struct sha1_array *ref = info->ref;
 485        unsigned int i, nr;
 486        int *shallow, nr_shallow = 0;
 487        struct paint_info pi;
 488
 489        trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 490        ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
 491        for (i = 0; i < info->nr_ours; i++)
 492                shallow[nr_shallow++] = info->ours[i];
 493        for (i = 0; i < info->nr_theirs; i++)
 494                shallow[nr_shallow++] = info->theirs[i];
 495
 496        /*
 497         * Prepare the commit graph to track what refs can reach what
 498         * (new) shallow commits.
 499         */
 500        nr = get_max_object_index();
 501        for (i = 0; i < nr; i++) {
 502                struct object *o = get_indexed_object(i);
 503                if (!o || o->type != OBJ_COMMIT)
 504                        continue;
 505
 506                o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 507        }
 508
 509        memset(&pi, 0, sizeof(pi));
 510        init_ref_bitmap(&pi.ref_bitmap);
 511        pi.nr_bits = ref->nr;
 512
 513        /*
 514         * "--not --all" to cut short the traversal if new refs
 515         * connect to old refs. If not (e.g. force ref updates) it'll
 516         * have to go down to the current shallow commits.
 517         */
 518        head_ref(mark_uninteresting, NULL);
 519        for_each_ref(mark_uninteresting, NULL);
 520
 521        /* Mark potential bottoms so we won't go out of bound */
 522        for (i = 0; i < nr_shallow; i++) {
 523                struct commit *c = lookup_commit(sha1[shallow[i]]);
 524                c->object.flags |= BOTTOM;
 525        }
 526
 527        for (i = 0; i < ref->nr; i++)
 528                paint_down(&pi, ref->sha1[i], i);
 529
 530        if (used) {
 531                int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
 532                memset(used, 0, sizeof(*used) * info->shallow->nr);
 533                for (i = 0; i < nr_shallow; i++) {
 534                        const struct commit *c = lookup_commit(sha1[shallow[i]]);
 535                        uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 536                        if (*map)
 537                                used[shallow[i]] = xmemdupz(*map, bitmap_size);
 538                }
 539                /*
 540                 * unreachable shallow commits are not removed from
 541                 * "ours" and "theirs". The user is supposed to run
 542                 * step 7 on every ref separately and not trust "ours"
 543                 * and "theirs" any more.
 544                 */
 545        } else
 546                post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 547
 548        clear_ref_bitmap(&pi.ref_bitmap);
 549        for (i = 0; i < pi.slab_count; i++)
 550                free(pi.slab[i]);
 551        free(pi.slab);
 552        free(shallow);
 553}
 554
 555struct commit_array {
 556        struct commit **commits;
 557        int nr, alloc;
 558};
 559
 560static int add_ref(const char *refname, const struct object_id *oid,
 561                   int flags, void *cb_data)
 562{
 563        struct commit_array *ca = cb_data;
 564        ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 565        ca->commits[ca->nr] = lookup_commit_reference_gently(oid->hash, 1);
 566        if (ca->commits[ca->nr])
 567                ca->nr++;
 568        return 0;
 569}
 570
 571static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 572{
 573        int i;
 574        if (!ref_status)
 575                return;
 576        for (i = 0; i < nr; i++)
 577                if (bitmap[i / 32] & (1 << (i % 32)))
 578                        ref_status[i]++;
 579}
 580
 581/*
 582 * Step 7, reachability test on "ours" at commit level
 583 */
 584static void post_assign_shallow(struct shallow_info *info,
 585                                struct ref_bitmap *ref_bitmap,
 586                                int *ref_status)
 587{
 588        unsigned char (*sha1)[20] = info->shallow->sha1;
 589        struct commit *c;
 590        uint32_t **bitmap;
 591        int dst, i, j;
 592        int bitmap_nr = (info->ref->nr + 31) / 32;
 593        struct commit_array ca;
 594
 595        trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 596        if (ref_status)
 597                memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 598
 599        /* Remove unreachable shallow commits from "theirs" */
 600        for (i = dst = 0; i < info->nr_theirs; i++) {
 601                if (i != dst)
 602                        info->theirs[dst] = info->theirs[i];
 603                c = lookup_commit(sha1[info->theirs[i]]);
 604                bitmap = ref_bitmap_at(ref_bitmap, c);
 605                if (!*bitmap)
 606                        continue;
 607                for (j = 0; j < bitmap_nr; j++)
 608                        if (bitmap[0][j]) {
 609                                update_refstatus(ref_status, info->ref->nr, *bitmap);
 610                                dst++;
 611                                break;
 612                        }
 613        }
 614        info->nr_theirs = dst;
 615
 616        memset(&ca, 0, sizeof(ca));
 617        head_ref(add_ref, &ca);
 618        for_each_ref(add_ref, &ca);
 619
 620        /* Remove unreachable shallow commits from "ours" */
 621        for (i = dst = 0; i < info->nr_ours; i++) {
 622                if (i != dst)
 623                        info->ours[dst] = info->ours[i];
 624                c = lookup_commit(sha1[info->ours[i]]);
 625                bitmap = ref_bitmap_at(ref_bitmap, c);
 626                if (!*bitmap)
 627                        continue;
 628                for (j = 0; j < bitmap_nr; j++)
 629                        if (bitmap[0][j] &&
 630                            /* Step 7, reachability test at commit level */
 631                            !in_merge_bases_many(c, ca.nr, ca.commits)) {
 632                                update_refstatus(ref_status, info->ref->nr, *bitmap);
 633                                dst++;
 634                                break;
 635                        }
 636        }
 637        info->nr_ours = dst;
 638
 639        free(ca.commits);
 640}
 641
 642/* (Delayed) step 7, reachability test at commit level */
 643int delayed_reachability_test(struct shallow_info *si, int c)
 644{
 645        if (si->need_reachability_test[c]) {
 646                struct commit *commit = lookup_commit(si->shallow->sha1[c]);
 647
 648                if (!si->commits) {
 649                        struct commit_array ca;
 650
 651                        memset(&ca, 0, sizeof(ca));
 652                        head_ref(add_ref, &ca);
 653                        for_each_ref(add_ref, &ca);
 654                        si->commits = ca.commits;
 655                        si->nr_commits = ca.nr;
 656                }
 657
 658                si->reachable[c] = in_merge_bases_many(commit,
 659                                                       si->nr_commits,
 660                                                       si->commits);
 661                si->need_reachability_test[c] = 0;
 662        }
 663        return si->reachable[c];
 664}