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 #include <time.h>
   7 #include <sys/wait.h>
   8
   9 static int quiet;
  10 static int verbose;
  11 static const char fetch_pack_usage[] =
  12 "git-fetch-pack [-q] [-v] [--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 static struct commit_list *rev_list = NULL;
  22 static int non_common_revs = 0, multi_ack = 0;
  23
  24 static void rev_list_push(struct commit *commit, int mark)
  25 {
  26         if (!(commit->object.flags & mark)) {
  27                 commit->object.flags |= mark;
  28
  29                 if (!(commit->object.parsed))
  30                         parse_commit(commit);
  31
  32                 insert_by_date(commit, &rev_list);
  33
  34                 if (!(commit->object.flags & COMMON))
  35                         non_common_revs++;
  36         }
  37 }
  38
  39 static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
  40 {
  41         struct object *o = deref_tag(parse_object(sha1), path, 0);
  42
  43         if (o && o->type == commit_type)
  44                 rev_list_push((struct commit *)o, SEEN);
  45
  46         return 0;
  47 }
  48
  49 /*
  50    This function marks a rev and its ancestors as common.
  51    In some cases, it is desirable to mark only the ancestors (for example
  52    when only the server does not yet know that they are common).
  53 */
  54
  55 static void mark_common(struct commit *commit,
  56                 int ancestors_only, int dont_parse)
  57 {
  58         if (commit != NULL && !(commit->object.flags & COMMON)) {
  59                 struct object *o = (struct object *)commit;
  60
  61                 if (!ancestors_only)
  62                         o->flags |= COMMON;
  63
  64                 if (!(o->flags & SEEN))
  65                         rev_list_push(commit, SEEN);
  66                 else {
  67                         struct commit_list *parents;
  68
  69                         if (!ancestors_only && !(o->flags & POPPED))
  70                                 non_common_revs--;
  71                         if (!o->parsed && !dont_parse)
  72                                 parse_commit(commit);
  73
  74                         for (parents = commit->parents;
  75                                         parents;
  76                                         parents = parents->next)
  77                                 mark_common(parents->item, 0, dont_parse);
  78                 }
  79         }
  80 }
  81
  82 /*
  83   Get the next rev to send, ignoring the common.
  84 */
  85
  86 static const unsigned char* get_rev()
  87 {
  88         struct commit *commit = NULL;
  89
  90         while (commit == NULL) {
  91                 unsigned int mark;
  92                 struct commit_list* parents;
  93
  94                 if (rev_list == NULL || non_common_revs == 0)
  95                         return NULL;
  96
  97                 commit = rev_list->item;
  98                 if (!(commit->object.parsed))
  99                         parse_commit(commit);
 100                 commit->object.flags |= POPPED;
 101                 if (!(commit->object.flags & COMMON))
 102                         non_common_revs--;
 103
 104                 parents = commit->parents;
 105
 106                 if (commit->object.flags & COMMON) {
 107                         /* do not send "have", and ignore ancestors */
 108                         commit = NULL;
 109                         mark = COMMON | SEEN;
 110                 } else if (commit->object.flags & COMMON_REF)
 111                         /* send "have", and ignore ancestors */
 112                         mark = COMMON | SEEN;
 113                 else
 114                         /* send "have", also for its ancestors */
 115                         mark = SEEN;
 116
 117                 while (parents) {
 118                         if (!(parents->item->object.flags & SEEN))
 119                                 rev_list_push(parents->item, mark);
 120                         if (mark & COMMON)
 121                                 mark_common(parents->item, 1, 0);
 122                         parents = parents->next;
 123                 }
 124
 125                 rev_list = rev_list->next;
 126         }
 127
 128         return commit->object.sha1;
 129 }
 130
 131 static int find_common(int fd[2], unsigned char *result_sha1,
 132                        struct ref *refs)
 133 {
 134         int fetching;
 135         int count = 0, flushes = 0, retval;
 136         const unsigned char *sha1;
 137
 138         for_each_ref(rev_list_insert_ref);
 139
 140         fetching = 0;
 141         for ( ; refs ; refs = refs->next) {
 142                 unsigned char *remote = refs->old_sha1;
 143                 struct object *o;
 144
 145                 /*
 146                  * If that object is complete (i.e. it is an ancestor of a
 147                  * local ref), we tell them we have it but do not have to
 148                  * tell them about its ancestors, which they already know
 149                  * about.
 150                  *
 151                  * We use lookup_object here because we are only
 152                  * interested in the case we *know* the object is
 153                  * reachable and we have already scanned it.
 154                  */
 155                 if (((o = lookup_object(remote)) != NULL) &&
 156                                 (o->flags & COMPLETE)) {
 157                         continue;
 158                 }
 159
 160                 packet_write(fd[1], "want %s%s\n", sha1_to_hex(remote),
 161                         multi_ack ? " multi_ack" : "");
 162                 fetching++;
 163         }
 164         packet_flush(fd[1]);
 165         if (!fetching)
 166                 return 1;
 167
 168         flushes = 0;
 169         retval = -1;
 170         while ((sha1 = get_rev())) {
 171                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
 172                 if (verbose)
 173                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 174                 if (!(31 & ++count)) {
 175                         int ack;
 176
 177                         packet_flush(fd[1]);
 178                         flushes++;
 179
 180                         /*
 181                          * We keep one window "ahead" of the other side, and
 182                          * will wait for an ACK only on the next one
 183                          */
 184                         if (count == 32)
 185                                 continue;
 186
 187                         do {
 188                                 ack = get_ack(fd[0], result_sha1);
 189                                 if (verbose && ack)
 190                                         fprintf(stderr, "got ack %d %s\n", ack,
 191                                                         sha1_to_hex(result_sha1));
 192                                 if (ack == 1) {
 193                                         flushes = 0;
 194                                         multi_ack = 0;
 195                                         retval = 0;
 196                                         goto done;
 197                                 } else if (ack == 2) {
 198                                         struct commit *commit =
 199                                                 lookup_commit(result_sha1);
 200                                         mark_common(commit, 0, 1);
 201                                         retval = 0;
 202                                 }
 203                         } while (ack);
 204                         flushes--;
 205                 }
 206         }
 207 done:
 208         packet_write(fd[1], "done\n");
 209         if (verbose)
 210                 fprintf(stderr, "done\n");
 211         if (retval != 0) {
 212                 multi_ack = 0;
 213                 flushes++;
 214         }
 215         while (flushes || multi_ack) {
 216                 int ack = get_ack(fd[0], result_sha1);
 217                 if (ack) {
 218                         if (verbose)
 219                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 220                                         sha1_to_hex(result_sha1));
 221                         if (ack == 1)
 222                                 return 0;
 223                         multi_ack = 1;
 224                         continue;
 225                 }
 226                 flushes--;
 227         }
 228         return retval;
 229 }
 230
 231 static struct commit_list *complete = NULL;
 232
 233 static int mark_complete(const char *path, const unsigned char *sha1)
 234 {
 235         struct object *o = parse_object(sha1);
 236
 237         while (o && o->type == tag_type) {
 238                 struct tag *t = (struct tag *) o;
 239                 if (!t->tagged)
 240                         break; /* broken repository */
 241                 o->flags |= COMPLETE;
 242                 o = parse_object(t->tagged->sha1);
 243         }
 244         if (o && o->type == commit_type) {
 245                 struct commit *commit = (struct commit *)o;
 246                 commit->object.flags |= COMPLETE;
 247                 insert_by_date(commit, &complete);
 248         }
 249         return 0;
 250 }
 251
 252 static void mark_recent_complete_commits(unsigned long cutoff)
 253 {
 254         while (complete && cutoff <= complete->item->date) {
 255                 if (verbose)
 256                         fprintf(stderr, "Marking %s as complete\n",
 257                                 sha1_to_hex(complete->item->object.sha1));
 258                 pop_most_recent_commit(&complete, COMPLETE);
 259         }
 260 }
 261
 262 static void filter_refs(struct ref **refs, int nr_match, char **match)
 263 {
 264         struct ref *prev, *current, *next;
 265
 266         if (!nr_match)
 267                 return;
 268
 269         for (prev = NULL, current = *refs; current; current = next) {
 270                 next = current->next;
 271                 if ((!memcmp(current->name, "refs/", 5) &&
 272                                         check_ref_format(current->name + 5)) ||
 273                                 !path_match(current->name, nr_match, match)) {
 274                         if (prev == NULL)
 275                                 *refs = next;
 276                         else
 277                                 prev->next = next;
 278                         free(current);
 279                 } else
 280                         prev = current;
 281         }
 282 }
 283
 284 static int everything_local(struct ref **refs, int nr_match, char **match)
 285 {
 286         struct ref *ref;
 287         int retval;
 288         unsigned long cutoff = 0;
 289
 290         track_object_refs = 0;
 291         save_commit_buffer = 0;
 292
 293         for (ref = *refs; ref; ref = ref->next) {
 294                 struct object *o;
 295
 296                 o = parse_object(ref->old_sha1);
 297                 if (!o)
 298                         continue;
 299
 300                 /* We already have it -- which may mean that we were
 301                  * in sync with the other side at some time after
 302                  * that (it is OK if we guess wrong here).
 303                  */
 304                 if (o->type == commit_type) {
 305                         struct commit *commit = (struct commit *)o;
 306                         if (!cutoff || cutoff < commit->date)
 307                                 cutoff = commit->date;
 308                 }
 309         }
 310
 311         for_each_ref(mark_complete);
 312         if (cutoff)
 313                 mark_recent_complete_commits(cutoff);
 314
 315         /*
 316          * Mark all complete remote refs as common refs.
 317          * Don't mark them common yet; the server has to be told so first.
 318          */
 319         for (ref = *refs; ref; ref = ref->next) {
 320                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 321                                              NULL, 0);
 322
 323                 if (!o || o->type != commit_type || !(o->flags & COMPLETE))
 324                         continue;
 325
 326                 if (!(o->flags & SEEN)) {
 327                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 328
 329                         mark_common((struct commit *)o, 1, 1);
 330                 }
 331         }
 332
 333         filter_refs(refs, nr_match, match);
 334
 335         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 336                 const unsigned char *remote = ref->old_sha1;
 337                 unsigned char local[20];
 338                 struct object *o;
 339
 340                 o = lookup_object(remote);
 341                 if (!o || !(o->flags & COMPLETE)) {
 342                         retval = 0;
 343                         if (!verbose)
 344                                 continue;
 345                         fprintf(stderr,
 346                                 "want %s (%s)\n", sha1_to_hex(remote),
 347                                 ref->name);
 348                         continue;
 349                 }
 350
 351                 memcpy(ref->new_sha1, local, 20);
 352                 if (!verbose)
 353                         continue;
 354                 fprintf(stderr,
 355                         "already have %s (%s)\n", sha1_to_hex(remote),
 356                         ref->name);
 357         }
 358         return retval;
 359 }
 360
 361 static int fetch_pack(int fd[2], int nr_match, char **match)
 362 {
 363         struct ref *ref;
 364         unsigned char sha1[20];
 365         int status;
 366         pid_t pid;
 367
 368         get_remote_heads(fd[0], &ref, 0, NULL, 0);
 369         if (server_supports("multi_ack")) {
 370                 if (verbose)
 371                         fprintf(stderr, "Server supports multi_ack\n");
 372                 multi_ack = 1;
 373         }
 374         if (!ref) {
 375                 packet_flush(fd[1]);
 376                 die("no matching remote head");
 377         }
 378         if (everything_local(&ref, nr_match, match)) {
 379                 packet_flush(fd[1]);
 380                 goto all_done;
 381         }
 382         if (find_common(fd, sha1, ref) < 0)
 383                 fprintf(stderr, "warning: no common commits\n");
 384         pid = fork();
 385         if (pid < 0)
 386                 die("git-fetch-pack: unable to fork off git-unpack-objects");
 387         if (!pid) {
 388                 dup2(fd[0], 0);
 389                 close(fd[0]);
 390                 close(fd[1]);
 391                 execlp("git-unpack-objects", "git-unpack-objects",
 392                        quiet ? "-q" : NULL, NULL);
 393                 die("git-unpack-objects exec failed");
 394         }
 395         close(fd[0]);
 396         close(fd[1]);
 397         while (waitpid(pid, &status, 0) < 0) {
 398                 if (errno != EINTR)
 399                         die("waiting for git-unpack-objects: %s", strerror(errno));
 400         }
 401         if (WIFEXITED(status)) {
 402                 int code = WEXITSTATUS(status);
 403                 if (code)
 404                         die("git-unpack-objects died with error code %d", code);
 405 all_done:
 406                 while (ref) {
 407                         printf("%s %s\n",
 408                                sha1_to_hex(ref->old_sha1), ref->name);
 409                         ref = ref->next;
 410                 }
 411                 return 0;
 412         }
 413         if (WIFSIGNALED(status)) {
 414                 int sig = WTERMSIG(status);
 415                 die("git-unpack-objects died of signal %d", sig);
 416         }
 417         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 418 }
 419
 420 int main(int argc, char **argv)
 421 {
 422         int i, ret, nr_heads;
 423         char *dest = NULL, **heads;
 424         int fd[2];
 425         pid_t pid;
 426
 427         nr_heads = 0;
 428         heads = NULL;
 429         for (i = 1; i < argc; i++) {
 430                 char *arg = argv[i];
 431
 432                 if (*arg == '-') {
 433                         if (!strncmp("--exec=", arg, 7)) {
 434                                 exec = arg + 7;
 435                                 continue;
 436                         }
 437                         if (!strcmp("-q", arg)) {
 438                                 quiet = 1;
 439                                 continue;
 440                         }
 441                         if (!strcmp("-v", arg)) {
 442                                 verbose = 1;
 443                                 continue;
 444                         }
 445                         usage(fetch_pack_usage);
 446                 }
 447                 dest = arg;
 448                 heads = argv + i + 1;
 449                 nr_heads = argc - i - 1;
 450                 break;
 451         }
 452         if (!dest)
 453                 usage(fetch_pack_usage);
 454         pid = git_connect(fd, dest, exec);
 455         if (pid < 0)
 456                 return 1;
 457         ret = fetch_pack(fd, nr_heads, heads);
 458         close(fd[0]);
 459         close(fd[1]);
 460         finish_connect(pid);
 461         return ret;
 462 }