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 = NULL;
  28 static int non_common_revs = 0, multi_ack = 0, use_thin_pack = 0;
  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 == TYPE_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                 packet_write(fd[1], "want %s%s%s\n", sha1_to_hex(remote),
 169                              (multi_ack ? " multi_ack" : ""),
 170                              (use_thin_pack ? " thin-pack" : ""));
 171                 fetching++;
 172         }
 173         packet_flush(fd[1]);
 174         if (!fetching)
 175                 return 1;
 176
 177         flushes = 0;
 178         retval = -1;
 179         while ((sha1 = get_rev())) {
 180                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
 181                 if (verbose)
 182                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 183                 in_vain++;
 184                 if (!(31 & ++count)) {
 185                         int ack;
 186
 187                         packet_flush(fd[1]);
 188                         flushes++;
 189
 190                         /*
 191                          * We keep one window "ahead" of the other side, and
 192                          * will wait for an ACK only on the next one
 193                          */
 194                         if (count == 32)
 195                                 continue;
 196
 197                         do {
 198                                 ack = get_ack(fd[0], result_sha1);
 199                                 if (verbose && ack)
 200                                         fprintf(stderr, "got ack %d %s\n", ack,
 201                                                         sha1_to_hex(result_sha1));
 202                                 if (ack == 1) {
 203                                         flushes = 0;
 204                                         multi_ack = 0;
 205                                         retval = 0;
 206                                         goto done;
 207                                 } else if (ack == 2) {
 208                                         struct commit *commit =
 209                                                 lookup_commit(result_sha1);
 210                                         mark_common(commit, 0, 1);
 211                                         retval = 0;
 212                                         in_vain = 0;
 213                                         got_continue = 1;
 214                                 }
 215                         } while (ack);
 216                         flushes--;
 217                         if (got_continue && MAX_IN_VAIN < in_vain) {
 218                                 if (verbose)
 219                                         fprintf(stderr, "giving up\n");
 220                                 break; /* give up */
 221                         }
 222                 }
 223         }
 224 done:
 225         packet_write(fd[1], "done\n");
 226         if (verbose)
 227                 fprintf(stderr, "done\n");
 228         if (retval != 0) {
 229                 multi_ack = 0;
 230                 flushes++;
 231         }
 232         while (flushes || multi_ack) {
 233                 int ack = get_ack(fd[0], result_sha1);
 234                 if (ack) {
 235                         if (verbose)
 236                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 237                                         sha1_to_hex(result_sha1));
 238                         if (ack == 1)
 239                                 return 0;
 240                         multi_ack = 1;
 241                         continue;
 242                 }
 243                 flushes--;
 244         }
 245         return retval;
 246 }
 247
 248 static struct commit_list *complete = NULL;
 249
 250 static int mark_complete(const char *path, const unsigned char *sha1)
 251 {
 252         struct object *o = parse_object(sha1);
 253
 254         while (o && o->type == TYPE_TAG) {
 255                 struct tag *t = (struct tag *) o;
 256                 if (!t->tagged)
 257                         break; /* broken repository */
 258                 o->flags |= COMPLETE;
 259                 o = parse_object(t->tagged->sha1);
 260         }
 261         if (o && o->type == TYPE_COMMIT) {
 262                 struct commit *commit = (struct commit *)o;
 263                 commit->object.flags |= COMPLETE;
 264                 insert_by_date(commit, &complete);
 265         }
 266         return 0;
 267 }
 268
 269 static void mark_recent_complete_commits(unsigned long cutoff)
 270 {
 271         while (complete && cutoff <= complete->item->date) {
 272                 if (verbose)
 273                         fprintf(stderr, "Marking %s as complete\n",
 274                                 sha1_to_hex(complete->item->object.sha1));
 275                 pop_most_recent_commit(&complete, COMPLETE);
 276         }
 277 }
 278
 279 static void filter_refs(struct ref **refs, int nr_match, char **match)
 280 {
 281         struct ref **return_refs;
 282         struct ref *newlist = NULL;
 283         struct ref **newtail = &newlist;
 284         struct ref *ref, *next;
 285         struct ref *fastarray[32];
 286
 287         if (nr_match && !fetch_all) {
 288                 if (ARRAY_SIZE(fastarray) < nr_match)
 289                         return_refs = xcalloc(nr_match, sizeof(struct ref *));
 290                 else {
 291                         return_refs = fastarray;
 292                         memset(return_refs, 0, sizeof(struct ref *) * nr_match);
 293                 }
 294         }
 295         else
 296                 return_refs = NULL;
 297
 298         for (ref = *refs; ref; ref = next) {
 299                 next = ref->next;
 300                 if (!memcmp(ref->name, "refs/", 5) &&
 301                     check_ref_format(ref->name + 5))
 302                         ; /* trash */
 303                 else if (fetch_all) {
 304                         *newtail = ref;
 305                         ref->next = NULL;
 306                         newtail = &ref->next;
 307                         continue;
 308                 }
 309                 else {
 310                         int order = path_match(ref->name, nr_match, match);
 311                         if (order) {
 312                                 return_refs[order-1] = ref;
 313                                 continue; /* we will link it later */
 314                         }
 315                 }
 316                 free(ref);
 317         }
 318
 319         if (!fetch_all) {
 320                 int i;
 321                 for (i = 0; i < nr_match; i++) {
 322                         ref = return_refs[i];
 323                         if (ref) {
 324                                 *newtail = ref;
 325                                 ref->next = NULL;
 326                                 newtail = &ref->next;
 327                         }
 328                 }
 329                 if (return_refs != fastarray)
 330                         free(return_refs);
 331         }
 332         *refs = newlist;
 333 }
 334
 335 static int everything_local(struct ref **refs, int nr_match, char **match)
 336 {
 337         struct ref *ref;
 338         int retval;
 339         unsigned long cutoff = 0;
 340
 341         track_object_refs = 0;
 342         save_commit_buffer = 0;
 343
 344         for (ref = *refs; ref; ref = ref->next) {
 345                 struct object *o;
 346
 347                 o = parse_object(ref->old_sha1);
 348                 if (!o)
 349                         continue;
 350
 351                 /* We already have it -- which may mean that we were
 352                  * in sync with the other side at some time after
 353                  * that (it is OK if we guess wrong here).
 354                  */
 355                 if (o->type == TYPE_COMMIT) {
 356                         struct commit *commit = (struct commit *)o;
 357                         if (!cutoff || cutoff < commit->date)
 358                                 cutoff = commit->date;
 359                 }
 360         }
 361
 362         for_each_ref(mark_complete);
 363         if (cutoff)
 364                 mark_recent_complete_commits(cutoff);
 365
 366         /*
 367          * Mark all complete remote refs as common refs.
 368          * Don't mark them common yet; the server has to be told so first.
 369          */
 370         for (ref = *refs; ref; ref = ref->next) {
 371                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 372                                              NULL, 0);
 373
 374                 if (!o || o->type != TYPE_COMMIT || !(o->flags & COMPLETE))
 375                         continue;
 376
 377                 if (!(o->flags & SEEN)) {
 378                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 379
 380                         mark_common((struct commit *)o, 1, 1);
 381                 }
 382         }
 383
 384         filter_refs(refs, nr_match, match);
 385
 386         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 387                 const unsigned char *remote = ref->old_sha1;
 388                 unsigned char local[20];
 389                 struct object *o;
 390
 391                 o = lookup_object(remote);
 392                 if (!o || !(o->flags & COMPLETE)) {
 393                         retval = 0;
 394                         if (!verbose)
 395                                 continue;
 396                         fprintf(stderr,
 397                                 "want %s (%s)\n", sha1_to_hex(remote),
 398                                 ref->name);
 399                         continue;
 400                 }
 401
 402                 memcpy(ref->new_sha1, local, 20);
 403                 if (!verbose)
 404                         continue;
 405                 fprintf(stderr,
 406                         "already have %s (%s)\n", sha1_to_hex(remote),
 407                         ref->name);
 408         }
 409         return retval;
 410 }
 411
 412 static int fetch_pack(int fd[2], int nr_match, char **match)
 413 {
 414         struct ref *ref;
 415         unsigned char sha1[20];
 416         int status;
 417
 418         get_remote_heads(fd[0], &ref, 0, NULL, 0);
 419         if (server_supports("multi_ack")) {
 420                 if (verbose)
 421                         fprintf(stderr, "Server supports multi_ack\n");
 422                 multi_ack = 1;
 423         }
 424         if (!ref) {
 425                 packet_flush(fd[1]);
 426                 die("no matching remote head");
 427         }
 428         if (everything_local(&ref, nr_match, match)) {
 429                 packet_flush(fd[1]);
 430                 goto all_done;
 431         }
 432         if (find_common(fd, sha1, ref) < 0)
 433                 if (!keep_pack)
 434                         /* When cloning, it is not unusual to have
 435                          * no common commit.
 436                          */
 437                         fprintf(stderr, "warning: no common commits\n");
 438
 439         if (keep_pack)
 440                 status = receive_keep_pack(fd, "git-fetch-pack", quiet);
 441         else
 442                 status = receive_unpack_pack(fd, "git-fetch-pack", quiet);
 443
 444         if (status)
 445                 die("git-fetch-pack: fetch failed.");
 446
 447  all_done:
 448         while (ref) {
 449                 printf("%s %s\n",
 450                        sha1_to_hex(ref->old_sha1), ref->name);
 451                 ref = ref->next;
 452         }
 453         return 0;
 454 }
 455
 456 int main(int argc, char **argv)
 457 {
 458         int i, ret, nr_heads;
 459         char *dest = NULL, **heads;
 460         int fd[2];
 461         pid_t pid;
 462
 463         setup_git_directory();
 464
 465         nr_heads = 0;
 466         heads = NULL;
 467         for (i = 1; i < argc; i++) {
 468                 char *arg = argv[i];
 469
 470                 if (*arg == '-') {
 471                         if (!strncmp("--exec=", arg, 7)) {
 472                                 exec = arg + 7;
 473                                 continue;
 474                         }
 475                         if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
 476                                 quiet = 1;
 477                                 continue;
 478                         }
 479                         if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
 480                                 keep_pack = 1;
 481                                 continue;
 482                         }
 483                         if (!strcmp("--thin", arg)) {
 484                                 use_thin_pack = 1;
 485                                 continue;
 486                         }
 487                         if (!strcmp("--all", arg)) {
 488                                 fetch_all = 1;
 489                                 continue;
 490                         }
 491                         if (!strcmp("-v", arg)) {
 492                                 verbose = 1;
 493                                 continue;
 494                         }
 495                         usage(fetch_pack_usage);
 496                 }
 497                 dest = arg;
 498                 heads = argv + i + 1;
 499                 nr_heads = argc - i - 1;
 500                 break;
 501         }
 502         if (!dest)
 503                 usage(fetch_pack_usage);
 504         if (keep_pack)
 505                 use_thin_pack = 0;
 506         pid = git_connect(fd, dest, exec);
 507         if (pid < 0)
 508                 return 1;
 509         ret = fetch_pack(fd, nr_heads, heads);
 510         close(fd[0]);
 511         close(fd[1]);
 512         finish_connect(pid);
 513
 514         if (!ret && nr_heads) {
 515                 /* If the heads to pull were given, we should have
 516                  * consumed all of them by matching the remote.
 517                  * Otherwise, 'git-fetch remote no-such-ref' would
 518                  * silently succeed without issuing an error.
 519                  */
 520                 for (i = 0; i < nr_heads; i++)
 521                         if (heads[i] && heads[i][0]) {
 522                                 error("no such remote ref %s", heads[i]);
 523                                 ret = 1;
 524                         }
 525         }
 526
 527         return ret;
 528 }