fetch-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6
   7 static int keep_pack;
   8 static int quiet;
   9 static int verbose;
  10 static int fetch_all;
  11 static const char fetch_pack_usage[] =
  12 "git-fetch-pack [--all] [-q] [-v] [-k] [--thin] [--exec=upload-pack] [host:]directory <refs>...";
  13 static const char *exec = "git-upload-pack";
  14
  15 #define COMPLETE        (1U << 0)
  16 #define COMMON          (1U << 1)
  17 #define COMMON_REF      (1U << 2)
  18 #define SEEN            (1U << 3)
  19 #define POPPED          (1U << 4)
  20
  21 /*
  22  * After sending this many "have"s if we do not get any new ACK , we
  23  * give up traversing our history.
  24  */
  25 #define MAX_IN_VAIN 256
  26
  27 static struct commit_list *rev_list;
  28 static int non_common_revs, multi_ack, use_thin_pack, use_sideband;
  29
  30 static void rev_list_push(struct commit *commit, int mark)
  31 {
  32         if (!(commit->object.flags & mark)) {
  33                 commit->object.flags |= mark;
  34
  35                 if (!(commit->object.parsed))
  36                         parse_commit(commit);
  37
  38                 insert_by_date(commit, &rev_list);
  39
  40                 if (!(commit->object.flags & COMMON))
  41                         non_common_revs++;
  42         }
  43 }
  44
  45 static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
  46 {
  47         struct object *o = deref_tag(parse_object(sha1), path, 0);
  48
  49         if (o && o->type == OBJ_COMMIT)
  50                 rev_list_push((struct commit *)o, SEEN);
  51
  52         return 0;
  53 }
  54
  55 /*
  56    This function marks a rev and its ancestors as common.
  57    In some cases, it is desirable to mark only the ancestors (for example
  58    when only the server does not yet know that they are common).
  59 */
  60
  61 static void mark_common(struct commit *commit,
  62                 int ancestors_only, int dont_parse)
  63 {
  64         if (commit != NULL && !(commit->object.flags & COMMON)) {
  65                 struct object *o = (struct object *)commit;
  66
  67                 if (!ancestors_only)
  68                         o->flags |= COMMON;
  69
  70                 if (!(o->flags & SEEN))
  71                         rev_list_push(commit, SEEN);
  72                 else {
  73                         struct commit_list *parents;
  74
  75                         if (!ancestors_only && !(o->flags & POPPED))
  76                                 non_common_revs--;
  77                         if (!o->parsed && !dont_parse)
  78                                 parse_commit(commit);
  79
  80                         for (parents = commit->parents;
  81                                         parents;
  82                                         parents = parents->next)
  83                                 mark_common(parents->item, 0, dont_parse);
  84                 }
  85         }
  86 }
  87
  88 /*
  89   Get the next rev to send, ignoring the common.
  90 */
  91
  92 static const unsigned char* get_rev(void)
  93 {
  94         struct commit *commit = NULL;
  95
  96         while (commit == NULL) {
  97                 unsigned int mark;
  98                 struct commit_list* parents;
  99
 100                 if (rev_list == NULL || non_common_revs == 0)
 101                         return NULL;
 102
 103                 commit = rev_list->item;
 104                 if (!(commit->object.parsed))
 105                         parse_commit(commit);
 106                 commit->object.flags |= POPPED;
 107                 if (!(commit->object.flags & COMMON))
 108                         non_common_revs--;
 109
 110                 parents = commit->parents;
 111
 112                 if (commit->object.flags & COMMON) {
 113                         /* do not send "have", and ignore ancestors */
 114                         commit = NULL;
 115                         mark = COMMON | SEEN;
 116                 } else if (commit->object.flags & COMMON_REF)
 117                         /* send "have", and ignore ancestors */
 118                         mark = COMMON | SEEN;
 119                 else
 120                         /* send "have", also for its ancestors */
 121                         mark = SEEN;
 122
 123                 while (parents) {
 124                         if (!(parents->item->object.flags & SEEN))
 125                                 rev_list_push(parents->item, mark);
 126                         if (mark & COMMON)
 127                                 mark_common(parents->item, 1, 0);
 128                         parents = parents->next;
 129                 }
 130
 131                 rev_list = rev_list->next;
 132         }
 133
 134         return commit->object.sha1;
 135 }
 136
 137 static int find_common(int fd[2], unsigned char *result_sha1,
 138                        struct ref *refs)
 139 {
 140         int fetching;
 141         int count = 0, flushes = 0, retval;
 142         const unsigned char *sha1;
 143         unsigned in_vain = 0;
 144         int got_continue = 0;
 145
 146         for_each_ref(rev_list_insert_ref);
 147
 148         fetching = 0;
 149         for ( ; refs ; refs = refs->next) {
 150                 unsigned char *remote = refs->old_sha1;
 151                 struct object *o;
 152
 153                 /*
 154                  * If that object is complete (i.e. it is an ancestor of a
 155                  * local ref), we tell them we have it but do not have to
 156                  * tell them about its ancestors, which they already know
 157                  * about.
 158                  *
 159                  * We use lookup_object here because we are only
 160                  * interested in the case we *know* the object is
 161                  * reachable and we have already scanned it.
 162                  */
 163                 if (((o = lookup_object(remote)) != NULL) &&
 164                                 (o->flags & COMPLETE)) {
 165                         continue;
 166                 }
 167
 168                 if (!fetching)
 169                         packet_write(fd[1], "want %s%s%s%s\n",
 170                                      sha1_to_hex(remote),
 171                                      (multi_ack ? " multi_ack" : ""),
 172                                      (use_sideband ? " side-band" : ""),
 173                                      (use_thin_pack ? " thin-pack" : ""));
 174                 else
 175                         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
 176                 fetching++;
 177         }
 178         packet_flush(fd[1]);
 179         if (!fetching)
 180                 return 1;
 181
 182         flushes = 0;
 183         retval = -1;
 184         while ((sha1 = get_rev())) {
 185                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
 186                 if (verbose)
 187                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 188                 in_vain++;
 189                 if (!(31 & ++count)) {
 190                         int ack;
 191
 192                         packet_flush(fd[1]);
 193                         flushes++;
 194
 195                         /*
 196                          * We keep one window "ahead" of the other side, and
 197                          * will wait for an ACK only on the next one
 198                          */
 199                         if (count == 32)
 200                                 continue;
 201
 202                         do {
 203                                 ack = get_ack(fd[0], result_sha1);
 204                                 if (verbose && ack)
 205                                         fprintf(stderr, "got ack %d %s\n", ack,
 206                                                         sha1_to_hex(result_sha1));
 207                                 if (ack == 1) {
 208                                         flushes = 0;
 209                                         multi_ack = 0;
 210                                         retval = 0;
 211                                         goto done;
 212                                 } else if (ack == 2) {
 213                                         struct commit *commit =
 214                                                 lookup_commit(result_sha1);
 215                                         mark_common(commit, 0, 1);
 216                                         retval = 0;
 217                                         in_vain = 0;
 218                                         got_continue = 1;
 219                                 }
 220                         } while (ack);
 221                         flushes--;
 222                         if (got_continue && MAX_IN_VAIN < in_vain) {
 223                                 if (verbose)
 224                                         fprintf(stderr, "giving up\n");
 225                                 break; /* give up */
 226                         }
 227                 }
 228         }
 229 done:
 230         packet_write(fd[1], "done\n");
 231         if (verbose)
 232                 fprintf(stderr, "done\n");
 233         if (retval != 0) {
 234                 multi_ack = 0;
 235                 flushes++;
 236         }
 237         while (flushes || multi_ack) {
 238                 int ack = get_ack(fd[0], result_sha1);
 239                 if (ack) {
 240                         if (verbose)
 241                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 242                                         sha1_to_hex(result_sha1));
 243                         if (ack == 1)
 244                                 return 0;
 245                         multi_ack = 1;
 246                         continue;
 247                 }
 248                 flushes--;
 249         }
 250         return retval;
 251 }
 252
 253 static struct commit_list *complete;
 254
 255 static int mark_complete(const char *path, const unsigned char *sha1)
 256 {
 257         struct object *o = parse_object(sha1);
 258
 259         while (o && o->type == OBJ_TAG) {
 260                 struct tag *t = (struct tag *) o;
 261                 if (!t->tagged)
 262                         break; /* broken repository */
 263                 o->flags |= COMPLETE;
 264                 o = parse_object(t->tagged->sha1);
 265         }
 266         if (o && o->type == OBJ_COMMIT) {
 267                 struct commit *commit = (struct commit *)o;
 268                 commit->object.flags |= COMPLETE;
 269                 insert_by_date(commit, &complete);
 270         }
 271         return 0;
 272 }
 273
 274 static void mark_recent_complete_commits(unsigned long cutoff)
 275 {
 276         while (complete && cutoff <= complete->item->date) {
 277                 if (verbose)
 278                         fprintf(stderr, "Marking %s as complete\n",
 279                                 sha1_to_hex(complete->item->object.sha1));
 280                 pop_most_recent_commit(&complete, COMPLETE);
 281         }
 282 }
 283
 284 static void filter_refs(struct ref **refs, int nr_match, char **match)
 285 {
 286         struct ref **return_refs;
 287         struct ref *newlist = NULL;
 288         struct ref **newtail = &newlist;
 289         struct ref *ref, *next;
 290         struct ref *fastarray[32];
 291
 292         if (nr_match && !fetch_all) {
 293                 if (ARRAY_SIZE(fastarray) < nr_match)
 294                         return_refs = xcalloc(nr_match, sizeof(struct ref *));
 295                 else {
 296                         return_refs = fastarray;
 297                         memset(return_refs, 0, sizeof(struct ref *) * nr_match);
 298                 }
 299         }
 300         else
 301                 return_refs = NULL;
 302
 303         for (ref = *refs; ref; ref = next) {
 304                 next = ref->next;
 305                 if (!memcmp(ref->name, "refs/", 5) &&
 306                     check_ref_format(ref->name + 5))
 307                         ; /* trash */
 308                 else if (fetch_all) {
 309                         *newtail = ref;
 310                         ref->next = NULL;
 311                         newtail = &ref->next;
 312                         continue;
 313                 }
 314                 else {
 315                         int order = path_match(ref->name, nr_match, match);
 316                         if (order) {
 317                                 return_refs[order-1] = ref;
 318                                 continue; /* we will link it later */
 319                         }
 320                 }
 321                 free(ref);
 322         }
 323
 324         if (!fetch_all) {
 325                 int i;
 326                 for (i = 0; i < nr_match; i++) {
 327                         ref = return_refs[i];
 328                         if (ref) {
 329                                 *newtail = ref;
 330                                 ref->next = NULL;
 331                                 newtail = &ref->next;
 332                         }
 333                 }
 334                 if (return_refs != fastarray)
 335                         free(return_refs);
 336         }
 337         *refs = newlist;
 338 }
 339
 340 static int everything_local(struct ref **refs, int nr_match, char **match)
 341 {
 342         struct ref *ref;
 343         int retval;
 344         unsigned long cutoff = 0;
 345
 346         track_object_refs = 0;
 347         save_commit_buffer = 0;
 348
 349         for (ref = *refs; ref; ref = ref->next) {
 350                 struct object *o;
 351
 352                 o = parse_object(ref->old_sha1);
 353                 if (!o)
 354                         continue;
 355
 356                 /* We already have it -- which may mean that we were
 357                  * in sync with the other side at some time after
 358                  * that (it is OK if we guess wrong here).
 359                  */
 360                 if (o->type == OBJ_COMMIT) {
 361                         struct commit *commit = (struct commit *)o;
 362                         if (!cutoff || cutoff < commit->date)
 363                                 cutoff = commit->date;
 364                 }
 365         }
 366
 367         for_each_ref(mark_complete);
 368         if (cutoff)
 369                 mark_recent_complete_commits(cutoff);
 370
 371         /*
 372          * Mark all complete remote refs as common refs.
 373          * Don't mark them common yet; the server has to be told so first.
 374          */
 375         for (ref = *refs; ref; ref = ref->next) {
 376                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 377                                              NULL, 0);
 378
 379                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 380                         continue;
 381
 382                 if (!(o->flags & SEEN)) {
 383                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 384
 385                         mark_common((struct commit *)o, 1, 1);
 386                 }
 387         }
 388
 389         filter_refs(refs, nr_match, match);
 390
 391         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 392                 const unsigned char *remote = ref->old_sha1;
 393                 unsigned char local[20];
 394                 struct object *o;
 395
 396                 o = lookup_object(remote);
 397                 if (!o || !(o->flags & COMPLETE)) {
 398                         retval = 0;
 399                         if (!verbose)
 400                                 continue;
 401                         fprintf(stderr,
 402                                 "want %s (%s)\n", sha1_to_hex(remote),
 403                                 ref->name);
 404                         continue;
 405                 }
 406
 407                 hashcpy(ref->new_sha1, local);
 408                 if (!verbose)
 409                         continue;
 410                 fprintf(stderr,
 411                         "already have %s (%s)\n", sha1_to_hex(remote),
 412                         ref->name);
 413         }
 414         return retval;
 415 }
 416
 417 static int fetch_pack(int fd[2], int nr_match, char **match)
 418 {
 419         struct ref *ref;
 420         unsigned char sha1[20];
 421         int status;
 422
 423         get_remote_heads(fd[0], &ref, 0, NULL, 0);
 424         if (server_supports("multi_ack")) {
 425                 if (verbose)
 426                         fprintf(stderr, "Server supports multi_ack\n");
 427                 multi_ack = 1;
 428         }
 429         if (server_supports("side-band")) {
 430                 if (verbose)
 431                         fprintf(stderr, "Server supports side-band\n");
 432                 use_sideband = 1;
 433         }
 434         if (!ref) {
 435                 packet_flush(fd[1]);
 436                 die("no matching remote head");
 437         }
 438         if (everything_local(&ref, nr_match, match)) {
 439                 packet_flush(fd[1]);
 440                 goto all_done;
 441         }
 442         if (find_common(fd, sha1, ref) < 0)
 443                 if (!keep_pack)
 444                         /* When cloning, it is not unusual to have
 445                          * no common commit.
 446                          */
 447                         fprintf(stderr, "warning: no common commits\n");
 448
 449         if (keep_pack)
 450                 status = receive_keep_pack(fd, "git-fetch-pack", quiet, use_sideband);
 451         else
 452                 status = receive_unpack_pack(fd, "git-fetch-pack", quiet, use_sideband);
 453
 454         if (status)
 455                 die("git-fetch-pack: fetch failed.");
 456
 457  all_done:
 458         while (ref) {
 459                 printf("%s %s\n",
 460                        sha1_to_hex(ref->old_sha1), ref->name);
 461                 ref = ref->next;
 462         }
 463         return 0;
 464 }
 465
 466 int main(int argc, char **argv)
 467 {
 468         int i, ret, nr_heads;
 469         char *dest = NULL, **heads;
 470         int fd[2];
 471         pid_t pid;
 472
 473         setup_git_directory();
 474
 475         nr_heads = 0;
 476         heads = NULL;
 477         for (i = 1; i < argc; i++) {
 478                 char *arg = argv[i];
 479
 480                 if (*arg == '-') {
 481                         if (!strncmp("--exec=", arg, 7)) {
 482                                 exec = arg + 7;
 483                                 continue;
 484                         }
 485                         if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
 486                                 quiet = 1;
 487                                 continue;
 488                         }
 489                         if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
 490                                 keep_pack = 1;
 491                                 continue;
 492                         }
 493                         if (!strcmp("--thin", arg)) {
 494                                 use_thin_pack = 1;
 495                                 continue;
 496                         }
 497                         if (!strcmp("--all", arg)) {
 498                                 fetch_all = 1;
 499                                 continue;
 500                         }
 501                         if (!strcmp("-v", arg)) {
 502                                 verbose = 1;
 503                                 continue;
 504                         }
 505                         usage(fetch_pack_usage);
 506                 }
 507                 dest = arg;
 508                 heads = argv + i + 1;
 509                 nr_heads = argc - i - 1;
 510                 break;
 511         }
 512         if (!dest)
 513                 usage(fetch_pack_usage);
 514         if (keep_pack)
 515                 use_thin_pack = 0;
 516         pid = git_connect(fd, dest, exec);
 517         if (pid < 0)
 518                 return 1;
 519         ret = fetch_pack(fd, nr_heads, heads);
 520         close(fd[0]);
 521         close(fd[1]);
 522         ret |= finish_connect(pid);
 523
 524         if (!ret && nr_heads) {
 525                 /* If the heads to pull were given, we should have
 526                  * consumed all of them by matching the remote.
 527                  * Otherwise, 'git-fetch remote no-such-ref' would
 528                  * silently succeed without issuing an error.
 529                  */
 530                 for (i = 0; i < nr_heads; i++)
 531                         if (heads[i] && heads[i][0]) {
 532                                 error("no such remote ref %s", heads[i]);
 533                                 ret = 1;
 534                         }
 535         }
 536
 537         return !!ret;
 538 }