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 | COMMON)
  18 #define SEEN            (1U << 3)
  19 #define POPPED          (1U << 4)
  20
  21 static struct commit_list *rev_list = NULL;
  22 static struct commit_list *rev_list_end = NULL;
  23 static unsigned long non_common_revs = 0;
  24
  25 static void rev_list_append(struct commit *commit, int mark)
  26 {
  27         if (!(commit->object.flags & mark)) {
  28                 commit->object.flags |= mark;
  29
  30                 if (rev_list == NULL) {
  31                         commit_list_insert(commit, &rev_list);
  32                         rev_list_end = rev_list;
  33                 } else {
  34                         commit_list_insert(commit, &(rev_list_end->next));
  35                         rev_list_end = rev_list_end->next;
  36                 }
  37
  38                 if (!(commit->object.flags & COMMON))
  39                         non_common_revs++;
  40         }
  41 }
  42
  43 static int rev_list_append_sha1(const char *path, const unsigned char *sha1)
  44 {
  45         struct object *o = deref_tag(parse_object(sha1));
  46
  47         if (o->type == commit_type)
  48                 rev_list_append((struct commit *)o, SEEN);
  49
  50         return 0;
  51 }
  52
  53 static void mark_common(struct commit *commit)
  54 {
  55         if (commit != NULL && !(commit->object.flags & COMMON)) {
  56                 struct object *o = (struct object *)commit;
  57                 o->flags |= COMMON;
  58                 if (!(o->flags & SEEN))
  59                         rev_list_append(commit, SEEN);
  60                 else {
  61                         struct commit_list *parents;
  62
  63                         if (!(o->flags & POPPED))
  64                                 non_common_revs--;
  65                         if (!o->parsed)
  66                                 parse_commit(commit);
  67                         for (parents = commit->parents;
  68                                         parents;
  69                                         parents = parents->next)
  70                                 mark_common(parents->item);
  71                 }
  72         }
  73 }
  74
  75 /*
  76   Get the next rev to send, ignoring the common.
  77 */
  78
  79 static const unsigned char* get_rev()
  80 {
  81         struct commit *commit = NULL;
  82
  83         while (commit == NULL) {
  84                 unsigned int mark;
  85                 struct commit_list* parents;
  86
  87                 if (rev_list == NULL || non_common_revs == 0)
  88                         return NULL;
  89
  90                 commit = rev_list->item;
  91                 if (!(commit->object.parsed))
  92                         parse_commit(commit);
  93                 commit->object.flags |= POPPED;
  94                 if (!(commit->object.flags & COMMON))
  95                         non_common_revs--;
  96
  97                 parents = commit->parents;
  98
  99                 if (commit->object.flags & COMMON) {
 100                         /* do not send "have", and ignore ancestors */
 101                         commit = NULL;
 102                         mark = COMMON | SEEN;
 103                 } else if (commit->object.flags & COMMON_REF)
 104                         /* send "have", and ignore ancestors */
 105                         mark = COMMON | SEEN;
 106                 else
 107                         /* send "have", also for its ancestors */
 108                         mark = SEEN;
 109
 110                 while (parents) {
 111                         if (mark & COMMON)
 112                                 mark_common(parents->item);
 113                         else
 114                                 rev_list_append(parents->item, mark);
 115                         parents = parents->next;
 116                 }
 117
 118                 rev_list = rev_list->next;
 119         }
 120
 121         return commit->object.sha1;
 122 }
 123
 124 static int find_common(int fd[2], unsigned char *result_sha1,
 125                        struct ref *refs)
 126 {
 127         int fetching;
 128         int count = 0, flushes = 0, multi_ack = 0, retval;
 129         const unsigned char *sha1;
 130
 131         for_each_ref(rev_list_append_sha1);
 132
 133         fetching = 0;
 134         for ( ; refs ; refs = refs->next) {
 135                 unsigned char *remote = refs->old_sha1;
 136                 struct object *o;
 137
 138                 /*
 139                  * If that object is complete (i.e. it is an ancestor of a
 140                  * local ref), we tell them we have it but do not have to
 141                  * tell them about its ancestors, which they already know
 142                  * about.
 143                  *
 144                  * We use lookup_object here because we are only
 145                  * interested in the case we *know* the object is
 146                  * reachable and we have already scanned it.
 147                  */
 148                 if (((o = lookup_object(remote)) != NULL) &&
 149                     (o->flags & COMPLETE)) {
 150                         o = deref_tag(o);
 151
 152                         if (o->type == commit_type)
 153                                 rev_list_append((struct commit *)o,
 154                                                 COMMON_REF | SEEN);
 155
 156                         continue;
 157                 }
 158
 159                 packet_write(fd[1], "want %s multi_ack\n", sha1_to_hex(remote));
 160                 fetching++;
 161         }
 162         packet_flush(fd[1]);
 163         if (!fetching)
 164                 return 1;
 165
 166         flushes = 0;
 167         retval = -1;
 168         while ((sha1 = get_rev())) {
 169                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
 170                 if (verbose)
 171                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 172                 if (!(31 & ++count)) {
 173                         int ack;
 174
 175                         packet_flush(fd[1]);
 176                         flushes++;
 177
 178                         /*
 179                          * We keep one window "ahead" of the other side, and
 180                          * will wait for an ACK only on the next one
 181                          */
 182                         if (count == 32)
 183                                 continue;
 184
 185                         do {
 186                                 ack = get_ack(fd[0], result_sha1);
 187                                 if (verbose && ack)
 188                                         fprintf(stderr, "got ack %d %s\n", ack,
 189                                                         sha1_to_hex(result_sha1));
 190                                 if (ack == 1) {
 191                                         if (!multi_ack)
 192                                                 flushes = 0;
 193                                         retval = 0;
 194                                         goto done;
 195                                 } else if (ack == 2) {
 196                                         multi_ack = 1;
 197                                         mark_common((struct commit *)
 198                                                         lookup_object(result_sha1));
 199                                         retval = 0;
 200                                 }
 201                         } while(ack);
 202                         flushes--;
 203                 }
 204         }
 205 done:
 206         if (multi_ack) {
 207                 packet_flush(fd[1]);
 208                 flushes++;
 209         }
 210         packet_write(fd[1], "done\n");
 211         if (verbose)
 212                 fprintf(stderr, "done\n");
 213         if (retval != 0)
 214                 flushes++;
 215         while (flushes) {
 216                 if (get_ack(fd[0], result_sha1)) {
 217                         if (verbose)
 218                                 fprintf(stderr, "got ack %s\n",
 219                                         sha1_to_hex(result_sha1));
 220                         if (!multi_ack)
 221                                 return 0;
 222                         retval = 0;
 223                         continue;
 224                 }
 225                 flushes--;
 226         }
 227         return retval;
 228 }
 229
 230 static struct commit_list *complete = NULL;
 231
 232 static int mark_complete(const char *path, const unsigned char *sha1)
 233 {
 234         struct object *o = parse_object(sha1);
 235
 236         while (o && o->type == tag_type) {
 237                 struct tag *t = (struct tag *) o;
 238                 if (!t->tagged)
 239                         break; /* broken repository */
 240                 o->flags |= COMPLETE;
 241                 o = parse_object(t->tagged->sha1);
 242         }
 243         if (o && o->type == commit_type) {
 244                 struct commit *commit = (struct commit *)o;
 245                 commit->object.flags |= COMPLETE;
 246                 insert_by_date(commit, &complete);
 247         }
 248         return 0;
 249 }
 250
 251 static void mark_recent_complete_commits(unsigned long cutoff)
 252 {
 253         while (complete && cutoff <= complete->item->date) {
 254                 if (verbose)
 255                         fprintf(stderr, "Marking %s as complete\n",
 256                                 sha1_to_hex(complete->item->object.sha1));
 257                 pop_most_recent_commit(&complete, COMPLETE);
 258         }
 259 }
 260
 261 static int everything_local(struct ref *refs)
 262 {
 263         struct ref *ref;
 264         int retval;
 265         unsigned long cutoff = 0;
 266
 267         track_object_refs = 0;
 268         save_commit_buffer = 0;
 269
 270         for (ref = refs; ref; ref = ref->next) {
 271                 struct object *o;
 272
 273                 o = parse_object(ref->old_sha1);
 274                 if (!o)
 275                         continue;
 276
 277                 /* We already have it -- which may mean that we were
 278                  * in sync with the other side at some time after
 279                  * that (it is OK if we guess wrong here).
 280                  */
 281                 if (o->type == commit_type) {
 282                         struct commit *commit = (struct commit *)o;
 283                         if (!cutoff || cutoff < commit->date)
 284                                 cutoff = commit->date;
 285                 }
 286         }
 287
 288         for_each_ref(mark_complete);
 289         if (cutoff)
 290                 mark_recent_complete_commits(cutoff);
 291
 292         for (retval = 1; refs ; refs = refs->next) {
 293                 const unsigned char *remote = refs->old_sha1;
 294                 unsigned char local[20];
 295                 struct object *o;
 296
 297                 o = parse_object(remote);
 298                 if (!o || !(o->flags & COMPLETE)) {
 299                         retval = 0;
 300                         if (!verbose)
 301                                 continue;
 302                         fprintf(stderr,
 303                                 "want %s (%s)\n", sha1_to_hex(remote),
 304                                 refs->name);
 305                         continue;
 306                 }
 307
 308                 memcpy(refs->new_sha1, local, 20);
 309                 if (!verbose)
 310                         continue;
 311                 fprintf(stderr,
 312                         "already have %s (%s)\n", sha1_to_hex(remote),
 313                         refs->name);
 314         }
 315         return retval;
 316 }
 317
 318 static int fetch_pack(int fd[2], int nr_match, char **match)
 319 {
 320         struct ref *ref;
 321         unsigned char sha1[20];
 322         int status;
 323         pid_t pid;
 324
 325         get_remote_heads(fd[0], &ref, nr_match, match, 1);
 326         if (!ref) {
 327                 packet_flush(fd[1]);
 328                 die("no matching remote head");
 329         }
 330         if (everything_local(ref)) {
 331                 packet_flush(fd[1]);
 332                 goto all_done;
 333         }
 334         if (find_common(fd, sha1, ref) < 0)
 335                 fprintf(stderr, "warning: no common commits\n");
 336         pid = fork();
 337         if (pid < 0)
 338                 die("git-fetch-pack: unable to fork off git-unpack-objects");
 339         if (!pid) {
 340                 dup2(fd[0], 0);
 341                 close(fd[0]);
 342                 close(fd[1]);
 343                 execlp("git-unpack-objects", "git-unpack-objects",
 344                        quiet ? "-q" : NULL, NULL);
 345                 die("git-unpack-objects exec failed");
 346         }
 347         close(fd[0]);
 348         close(fd[1]);
 349         while (waitpid(pid, &status, 0) < 0) {
 350                 if (errno != EINTR)
 351                         die("waiting for git-unpack-objects: %s", strerror(errno));
 352         }
 353         if (WIFEXITED(status)) {
 354                 int code = WEXITSTATUS(status);
 355                 if (code)
 356                         die("git-unpack-objects died with error code %d", code);
 357 all_done:
 358                 while (ref) {
 359                         printf("%s %s\n",
 360                                sha1_to_hex(ref->old_sha1), ref->name);
 361                         ref = ref->next;
 362                 }
 363                 return 0;
 364         }
 365         if (WIFSIGNALED(status)) {
 366                 int sig = WTERMSIG(status);
 367                 die("git-unpack-objects died of signal %d", sig);
 368         }
 369         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 370 }
 371
 372 int main(int argc, char **argv)
 373 {
 374         int i, ret, nr_heads;
 375         char *dest = NULL, **heads;
 376         int fd[2];
 377         pid_t pid;
 378
 379         nr_heads = 0;
 380         heads = NULL;
 381         for (i = 1; i < argc; i++) {
 382                 char *arg = argv[i];
 383
 384                 if (*arg == '-') {
 385                         if (!strncmp("--exec=", arg, 7)) {
 386                                 exec = arg + 7;
 387                                 continue;
 388                         }
 389                         if (!strcmp("-q", arg)) {
 390                                 quiet = 1;
 391                                 continue;
 392                         }
 393                         if (!strcmp("-v", arg)) {
 394                                 verbose = 1;
 395                                 continue;
 396                         }
 397                         usage(fetch_pack_usage);
 398                 }
 399                 dest = arg;
 400                 heads = argv + i + 1;
 401                 nr_heads = argc - i - 1;
 402                 break;
 403         }
 404         if (!dest)
 405                 usage(fetch_pack_usage);
 406         pid = git_connect(fd, dest, exec);
 407         if (pid < 0)
 408                 return 1;
 409         ret = fetch_pack(fd, nr_heads, heads);
 410         close(fd[0]);
 411         close(fd[1]);
 412         finish_connect(pid);
 413         return ret;
 414 }