Andrew's git / gitweb.git / shallow.c
?
shallow.con commit fetch-pack.c: move shallow update code out of fetch_pack() (a796cce)
   1#include "cache.h"
   2#include "commit.h"
   3#include "tag.h"
   4#include "pkt-line.h"
   5#include "remote.h"
   6#include "refs.h"
   7#include "sha1-array.h"
   8#include "diff.h"
   9#include "revision.h"
  10#include "commit-slab.h"
  11
  12static int is_shallow = -1;
  13static struct stat shallow_stat;
  14static char *alternate_shallow_file;
  15
  16void set_alternate_shallow_file(const char *path)
  17{
  18        if (is_shallow != -1)
  19                die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
  20        free(alternate_shallow_file);
  21        alternate_shallow_file = path ? xstrdup(path) : NULL;
  22}
  23
  24int register_shallow(const unsigned char *sha1)
  25{
  26        struct commit_graft *graft =
  27                xmalloc(sizeof(struct commit_graft));
  28        struct commit *commit = lookup_commit(sha1);
  29
  30        hashcpy(graft->sha1, sha1);
  31        graft->nr_parent = -1;
  32        if (commit && commit->object.parsed)
  33                commit->parents = NULL;
  34        return register_commit_graft(graft, 0);
  35}
  36
  37int is_repository_shallow(void)
  38{
  39        FILE *fp;
  40        char buf[1024];
  41        const char *path = alternate_shallow_file;
  42
  43        if (is_shallow >= 0)
  44                return is_shallow;
  45
  46        if (!path)
  47                path = git_path("shallow");
  48        /*
  49         * fetch-pack sets '--shallow-file ""' as an indicator that no
  50         * shallow file should be used. We could just open it and it
  51         * will likely fail. But let's do an explicit check instead.
  52         */
  53        if (!*path ||
  54            stat(path, &shallow_stat) ||
  55            (fp = fopen(path, "r")) == NULL) {
  56                is_shallow = 0;
  57                return is_shallow;
  58        }
  59        is_shallow = 1;
  60
  61        while (fgets(buf, sizeof(buf), fp)) {
  62                unsigned char sha1[20];
  63                if (get_sha1_hex(buf, sha1))
  64                        die("bad shallow line: %s", buf);
  65                register_shallow(sha1);
  66        }
  67        fclose(fp);
  68        return is_shallow;
  69}
  70
  71struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
  72                int shallow_flag, int not_shallow_flag)
  73{
  74        int i = 0, cur_depth = 0;
  75        struct commit_list *result = NULL;
  76        struct object_array stack = OBJECT_ARRAY_INIT;
  77        struct commit *commit = NULL;
  78
  79        while (commit || i < heads->nr || stack.nr) {
  80                struct commit_list *p;
  81                if (!commit) {
  82                        if (i < heads->nr) {
  83                                commit = (struct commit *)
  84                                        deref_tag(heads->objects[i++].item, NULL, 0);
  85                                if (!commit || commit->object.type != OBJ_COMMIT) {
  86                                        commit = NULL;
  87                                        continue;
  88                                }
  89                                if (!commit->util)
  90                                        commit->util = xmalloc(sizeof(int));
  91                                *(int *)commit->util = 0;
  92                                cur_depth = 0;
  93                        } else {
  94                                commit = (struct commit *)
  95                                        stack.objects[--stack.nr].item;
  96                                cur_depth = *(int *)commit->util;
  97                        }
  98                }
  99                if (parse_commit(commit))
 100                        die("invalid commit");
 101                cur_depth++;
 102                if (cur_depth >= depth) {
 103                        commit_list_insert(commit, &result);
 104                        commit->object.flags |= shallow_flag;
 105                        commit = NULL;
 106                        continue;
 107                }
 108                commit->object.flags |= not_shallow_flag;
 109                for (p = commit->parents, commit = NULL; p; p = p->next) {
 110                        if (!p->item->util) {
 111                                int *pointer = xmalloc(sizeof(int));
 112                                p->item->util = pointer;
 113                                *pointer =  cur_depth;
 114                        } else {
 115                                int *pointer = p->item->util;
 116                                if (cur_depth >= *pointer)
 117                                        continue;
 118                                *pointer = cur_depth;
 119                        }
 120                        if (p->next)
 121                                add_object_array(&p->item->object,
 122                                                NULL, &stack);
 123                        else {
 124                                commit = p->item;
 125                                cur_depth = *(int *)commit->util;
 126                        }
 127                }
 128        }
 129
 130        return result;
 131}
 132
 133void check_shallow_file_for_update(void)
 134{
 135        struct stat st;
 136
 137        if (!is_shallow)
 138                return;
 139        else if (is_shallow == -1)
 140                die("BUG: shallow must be initialized by now");
 141
 142        if (stat(git_path("shallow"), &st))
 143                die("shallow file was removed during fetch");
 144        else if (st.st_mtime != shallow_stat.st_mtime
 145#ifdef USE_NSEC
 146                 || ST_MTIME_NSEC(st) != ST_MTIME_NSEC(shallow_stat)
 147#endif
 148                   )
 149                die("shallow file was changed during fetch");
 150}
 151
 152struct write_shallow_data {
 153        struct strbuf *out;
 154        int use_pack_protocol;
 155        int count;
 156};
 157
 158static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 159{
 160        struct write_shallow_data *data = cb_data;
 161        const char *hex = sha1_to_hex(graft->sha1);
 162        if (graft->nr_parent != -1)
 163                return 0;
 164        data->count++;
 165        if (data->use_pack_protocol)
 166                packet_buf_write(data->out, "shallow %s", hex);
 167        else {
 168                strbuf_addstr(data->out, hex);
 169                strbuf_addch(data->out, '\n');
 170        }
 171        return 0;
 172}
 173
 174int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 175                          const struct sha1_array *extra)
 176{
 177        struct write_shallow_data data;
 178        int i;
 179        data.out = out;
 180        data.use_pack_protocol = use_pack_protocol;
 181        data.count = 0;
 182        for_each_commit_graft(write_one_shallow, &data);
 183        if (!extra)
 184                return data.count;
 185        for (i = 0; i < extra->nr; i++) {
 186                strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
 187                strbuf_addch(out, '\n');
 188                data.count++;
 189        }
 190        return data.count;
 191}
 192
 193char *setup_temporary_shallow(const struct sha1_array *extra)
 194{
 195        struct strbuf sb = STRBUF_INIT;
 196        int fd;
 197
 198        if (write_shallow_commits(&sb, 0, extra)) {
 199                struct strbuf path = STRBUF_INIT;
 200                strbuf_addstr(&path, git_path("shallow_XXXXXX"));
 201                fd = xmkstemp(path.buf);
 202                if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 203                        die_errno("failed to write to %s",
 204                                  path.buf);
 205                close(fd);
 206                strbuf_release(&sb);
 207                return strbuf_detach(&path, NULL);
 208        }
 209        /*
 210         * is_repository_shallow() sees empty string as "no shallow
 211         * file".
 212         */
 213        return xstrdup("");
 214}
 215
 216void setup_alternate_shallow(struct lock_file *shallow_lock,
 217                             const char **alternate_shallow_file,
 218                             const struct sha1_array *extra)
 219{
 220        struct strbuf sb = STRBUF_INIT;
 221        int fd;
 222
 223        check_shallow_file_for_update();
 224        fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
 225                                       LOCK_DIE_ON_ERROR);
 226        if (write_shallow_commits(&sb, 0, extra)) {
 227                if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 228                        die_errno("failed to write to %s",
 229                                  shallow_lock->filename);
 230                *alternate_shallow_file = shallow_lock->filename;
 231        } else
 232                /*
 233                 * is_repository_shallow() sees empty string as "no
 234                 * shallow file".
 235                 */
 236                *alternate_shallow_file = "";
 237        strbuf_release(&sb);
 238}
 239
 240static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 241{
 242        int fd = *(int *)cb;
 243        if (graft->nr_parent == -1)
 244                packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
 245        return 0;
 246}
 247
 248void advertise_shallow_grafts(int fd)
 249{
 250        if (!is_repository_shallow())
 251                return;
 252        for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 253}
 254
 255#define TRACE_KEY "GIT_TRACE_SHALLOW"
 256
 257/*
 258 * Step 1, split sender shallow commits into "ours" and "theirs"
 259 * Step 2, clean "ours" based on .git/shallow
 260 */
 261void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
 262{
 263        int i;
 264        trace_printf_key(TRACE_KEY, "shallow: prepare_shallow_info\n");
 265        memset(info, 0, sizeof(*info));
 266        info->shallow = sa;
 267        if (!sa)
 268                return;
 269        info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
 270        info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
 271        for (i = 0; i < sa->nr; i++) {
 272                if (has_sha1_file(sa->sha1[i])) {
 273                        struct commit_graft *graft;
 274                        graft = lookup_commit_graft(sa->sha1[i]);
 275                        if (graft && graft->nr_parent < 0)
 276                                continue;
 277                        info->ours[info->nr_ours++] = i;
 278                } else
 279                        info->theirs[info->nr_theirs++] = i;
 280        }
 281}
 282
 283void clear_shallow_info(struct shallow_info *info)
 284{
 285        free(info->ours);
 286        free(info->theirs);
 287}
 288
 289/* Step 4, remove non-existent ones in "theirs" after getting the pack */
 290
 291void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 292{
 293        unsigned char (*sha1)[20] = info->shallow->sha1;
 294        int i, dst;
 295        trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_theirs_shallow\n");
 296        for (i = dst = 0; i < info->nr_theirs; i++) {
 297                if (i != dst)
 298                        info->theirs[dst] = info->theirs[i];
 299                if (has_sha1_file(sha1[info->theirs[i]]))
 300                        dst++;
 301        }
 302        info->nr_theirs = dst;
 303}
 304
 305/* Step 5, remove non-existent ones in "ours" in the pack */
 306void remove_nonexistent_ours_in_pack(struct shallow_info *info,
 307                                     struct packed_git *p)
 308{
 309        unsigned char (*sha1)[20] = info->shallow->sha1;
 310        int i, dst;
 311        trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_ours_in_pack\n");
 312        for (i = dst = 0; i < info->nr_ours; i++) {
 313                if (i != dst)
 314                        info->ours[dst] = info->ours[i];
 315                if (find_pack_entry_one(sha1[info->ours[i]], p))
 316                        dst++;
 317        }
 318        info->nr_ours = dst;
 319}
 320
 321define_commit_slab(ref_bitmap, uint32_t *);
 322
 323struct paint_info {
 324        struct ref_bitmap ref_bitmap;
 325        unsigned nr_bits;
 326        char **slab;
 327        char *free, *end;
 328        unsigned slab_count;
 329};
 330
 331static uint32_t *paint_alloc(struct paint_info *info)
 332{
 333        unsigned nr = (info->nr_bits + 31) / 32;
 334        unsigned size = nr * sizeof(uint32_t);
 335        void *p;
 336        if (!info->slab_count || info->free + size > info->end) {
 337                info->slab_count++;
 338                info->slab = xrealloc(info->slab,
 339                                      info->slab_count * sizeof(*info->slab));
 340                info->free = xmalloc(COMMIT_SLAB_SIZE);
 341                info->slab[info->slab_count - 1] = info->free;
 342                info->end = info->free + COMMIT_SLAB_SIZE;
 343        }
 344        p = info->free;
 345        info->free += size;
 346        return p;
 347}
 348
 349/*
 350 * Given a commit SHA-1, walk down to parents until either SEEN,
 351 * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 352 * all walked commits.
 353 */
 354static void paint_down(struct paint_info *info, const unsigned char *sha1,
 355                       int id)
 356{
 357        unsigned int i, nr;
 358        struct commit_list *head = NULL;
 359        int bitmap_nr = (info->nr_bits + 31) / 32;
 360        int bitmap_size = bitmap_nr * sizeof(uint32_t);
 361        uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
 362        uint32_t *bitmap = paint_alloc(info);
 363        struct commit *c = lookup_commit_reference_gently(sha1, 1);
 364        if (!c)
 365                return;
 366        memset(bitmap, 0, bitmap_size);
 367        bitmap[id / 32] |= (1 << (id % 32));
 368        commit_list_insert(c, &head);
 369        while (head) {
 370                struct commit_list *p;
 371                struct commit *c = head->item;
 372                uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 373
 374                p = head;
 375                head = head->next;
 376                free(p);
 377
 378                /* XXX check "UNINTERESTING" from pack bitmaps if available */
 379                if (c->object.flags & (SEEN | UNINTERESTING))
 380                        continue;
 381                else
 382                        c->object.flags |= SEEN;
 383
 384                if (*refs == NULL)
 385                        *refs = bitmap;
 386                else {
 387                        memcpy(tmp, *refs, bitmap_size);
 388                        for (i = 0; i < bitmap_nr; i++)
 389                                tmp[i] |= bitmap[i];
 390                        if (memcmp(tmp, *refs, bitmap_size)) {
 391                                *refs = paint_alloc(info);
 392                                memcpy(*refs, tmp, bitmap_size);
 393                        }
 394                }
 395
 396                if (c->object.flags & BOTTOM)
 397                        continue;
 398
 399                if (parse_commit(c))
 400                        die("unable to parse commit %s",
 401                            sha1_to_hex(c->object.sha1));
 402
 403                for (p = c->parents; p; p = p->next) {
 404                        uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
 405                                                          p->item);
 406                        if (p->item->object.flags & SEEN)
 407                                continue;
 408                        if (*p_refs == NULL || *p_refs == *refs)
 409                                *p_refs = *refs;
 410                        commit_list_insert(p->item, &head);
 411                }
 412        }
 413
 414        nr = get_max_object_index();
 415        for (i = 0; i < nr; i++) {
 416                struct object *o = get_indexed_object(i);
 417                if (o && o->type == OBJ_COMMIT)
 418                        o->flags &= ~SEEN;
 419        }
 420
 421        free(tmp);
 422}
 423
 424static int mark_uninteresting(const char *refname,
 425                              const unsigned char *sha1,
 426                              int flags, void *cb_data)
 427{
 428        struct commit *commit = lookup_commit_reference_gently(sha1, 1);
 429        if (!commit)
 430                return 0;
 431        commit->object.flags |= UNINTERESTING;
 432        mark_parents_uninteresting(commit);
 433        return 0;
 434}
 435
 436static void post_assign_shallow(struct shallow_info *info,
 437                                struct ref_bitmap *ref_bitmap,
 438                                int *ref_status);
 439/*
 440 * Step 6(+7), associate shallow commits with new refs
 441 *
 442 * info->ref must be initialized before calling this function.
 443 *
 444 * If used is not NULL, it's an array of info->shallow->nr
 445 * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 446 * m-th shallow commit from info->shallow.
 447 *
 448 * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 449 * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 450 * the ref needs some shallow commits from either info->ours or
 451 * info->theirs.
 452 */
 453void assign_shallow_commits_to_refs(struct shallow_info *info,
 454                                    uint32_t **used, int *ref_status)
 455{
 456        unsigned char (*sha1)[20] = info->shallow->sha1;
 457        struct sha1_array *ref = info->ref;
 458        unsigned int i, nr;
 459        int *shallow, nr_shallow = 0;
 460        struct paint_info pi;
 461
 462        trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
 463        shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
 464        for (i = 0; i < info->nr_ours; i++)
 465                shallow[nr_shallow++] = info->ours[i];
 466        for (i = 0; i < info->nr_theirs; i++)
 467                shallow[nr_shallow++] = info->theirs[i];
 468
 469        /*
 470         * Prepare the commit graph to track what refs can reach what
 471         * (new) shallow commits.
 472         */
 473        nr = get_max_object_index();
 474        for (i = 0; i < nr; i++) {
 475                struct object *o = get_indexed_object(i);
 476                if (!o || o->type != OBJ_COMMIT)
 477                        continue;
 478
 479                o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 480        }
 481
 482        memset(&pi, 0, sizeof(pi));
 483        init_ref_bitmap(&pi.ref_bitmap);
 484        pi.nr_bits = ref->nr;
 485
 486        /*
 487         * "--not --all" to cut short the traversal if new refs
 488         * connect to old refs. If not (e.g. force ref updates) it'll
 489         * have to go down to the current shallow commits.
 490         */
 491        head_ref(mark_uninteresting, NULL);
 492        for_each_ref(mark_uninteresting, NULL);
 493
 494        /* Mark potential bottoms so we won't go out of bound */
 495        for (i = 0; i < nr_shallow; i++) {
 496                struct commit *c = lookup_commit(sha1[shallow[i]]);
 497                c->object.flags |= BOTTOM;
 498        }
 499
 500        for (i = 0; i < ref->nr; i++)
 501                paint_down(&pi, ref->sha1[i], i);
 502
 503        if (used) {
 504                int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
 505                memset(used, 0, sizeof(*used) * info->shallow->nr);
 506                for (i = 0; i < nr_shallow; i++) {
 507                        const struct commit *c = lookup_commit(sha1[shallow[i]]);
 508                        uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 509                        if (*map)
 510                                used[shallow[i]] = xmemdupz(*map, bitmap_size);
 511                }
 512                /*
 513                 * unreachable shallow commits are not removed from
 514                 * "ours" and "theirs". The user is supposed to run
 515                 * step 7 on every ref separately and not trust "ours"
 516                 * and "theirs" any more.
 517                 */
 518        } else
 519                post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 520
 521        clear_ref_bitmap(&pi.ref_bitmap);
 522        for (i = 0; i < pi.slab_count; i++)
 523                free(pi.slab[i]);
 524        free(pi.slab);
 525        free(shallow);
 526}
 527
 528struct commit_array {
 529        struct commit **commits;
 530        int nr, alloc;
 531};
 532
 533static int add_ref(const char *refname,
 534                   const unsigned char *sha1, int flags, void *cb_data)
 535{
 536        struct commit_array *ca = cb_data;
 537        ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 538        ca->commits[ca->nr] = lookup_commit_reference_gently(sha1, 1);
 539        if (ca->commits[ca->nr])
 540                ca->nr++;
 541        return 0;
 542}
 543
 544static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 545{
 546        int i;
 547        if (!ref_status)
 548                return;
 549        for (i = 0; i < nr; i++)
 550                if (bitmap[i / 32] & (1 << (i % 32)))
 551                        ref_status[i]++;
 552}
 553
 554/*
 555 * Step 7, reachability test on "ours" at commit level
 556 */
 557static void post_assign_shallow(struct shallow_info *info,
 558                                struct ref_bitmap *ref_bitmap,
 559                                int *ref_status)
 560{
 561        unsigned char (*sha1)[20] = info->shallow->sha1;
 562        struct commit *c;
 563        uint32_t **bitmap;
 564        int dst, i, j;
 565        int bitmap_nr = (info->ref->nr + 31) / 32;
 566        struct commit_array ca;
 567
 568        trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
 569        if (ref_status)
 570                memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 571
 572        /* Remove unreachable shallow commits from "theirs" */
 573        for (i = dst = 0; i < info->nr_theirs; i++) {
 574                if (i != dst)
 575                        info->theirs[dst] = info->theirs[i];
 576                c = lookup_commit(sha1[info->theirs[i]]);
 577                bitmap = ref_bitmap_at(ref_bitmap, c);
 578                if (!*bitmap)
 579                        continue;
 580                for (j = 0; j < bitmap_nr; j++)
 581                        if (bitmap[0][j]) {
 582                                update_refstatus(ref_status, info->ref->nr, *bitmap);
 583                                dst++;
 584                                break;
 585                        }
 586        }
 587        info->nr_theirs = dst;
 588
 589        memset(&ca, 0, sizeof(ca));
 590        head_ref(add_ref, &ca);
 591        for_each_ref(add_ref, &ca);
 592
 593        /* Remove unreachable shallow commits from "ours" */
 594        for (i = dst = 0; i < info->nr_ours; i++) {
 595                if (i != dst)
 596                        info->ours[dst] = info->ours[i];
 597                c = lookup_commit(sha1[info->ours[i]]);
 598                bitmap = ref_bitmap_at(ref_bitmap, c);
 599                if (!*bitmap)
 600                        continue;
 601                for (j = 0; j < bitmap_nr; j++)
 602                        if (bitmap[0][j] &&
 603                            /* Step 7, reachability test at commit level */
 604                            !in_merge_bases_many(c, ca.nr, ca.commits)) {
 605                                update_refstatus(ref_status, info->ref->nr, *bitmap);
 606                                dst++;
 607                                break;
 608                        }
 609        }
 610        info->nr_ours = dst;
 611
 612        free(ca.commits);
 613}