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
  17 static int find_common(int fd[2], unsigned char *result_sha1,
  18                        struct ref *refs)
  19 {
  20         int fetching;
  21         static char line[1000];
  22         static char rev_command[1024];
  23         int count = 0, flushes = 0, retval, rev_command_len;
  24         FILE *revs;
  25
  26         strcpy(rev_command, "git-rev-list $(git-rev-parse --all)");
  27         rev_command_len = strlen(rev_command);
  28         fetching = 0;
  29         for ( ; refs ; refs = refs->next) {
  30                 unsigned char *remote = refs->old_sha1;
  31                 struct object *o;
  32
  33                 /*
  34                  * If that object is complete (i.e. it is an ancestor of a
  35                  * local ref), we tell them we have it but do not have to
  36                  * tell them about its ancestors, which they already know
  37                  * about.
  38                  *
  39                  * We use lookup_object here because we are only
  40                  * interested in the case we *know* the object is
  41                  * reachable and we have already scanned it.
  42                  */
  43                 if (((o = lookup_object(remote)) != NULL) &&
  44                     (o->flags & COMPLETE)) {
  45                         struct commit_list *p;
  46                         struct commit *commit =
  47                                 (struct commit *) (o = deref_tag(o));
  48                         if (!o)
  49                                 goto repair;
  50                         if (o->type != commit_type)
  51                                 continue;
  52                         p = commit->parents;
  53                         while (p &&
  54                                rev_command_len + 44 < sizeof(rev_command)) {
  55                                 snprintf(rev_command + rev_command_len, 44,
  56                                          " ^%s",
  57                                          sha1_to_hex(p->item->object.sha1));
  58                                 rev_command_len += 43;
  59                                 p = p->next;
  60                         }
  61                         continue;
  62                 }
  63         repair:
  64                 packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
  65                 fetching++;
  66         }
  67         packet_flush(fd[1]);
  68         if (!fetching)
  69                 return 1;
  70
  71         revs = popen(rev_command, "r");
  72         if (!revs)
  73                 die("unable to run 'git-rev-list'");
  74
  75         flushes = 1;
  76         retval = -1;
  77         while (fgets(line, sizeof(line), revs) != NULL) {
  78                 unsigned char sha1[20];
  79                 if (get_sha1_hex(line, sha1))
  80                         die("git-fetch-pack: expected object name, got crud");
  81                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
  82                 if (verbose)
  83                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
  84                 if (!(31 & ++count)) {
  85                         packet_flush(fd[1]);
  86                         flushes++;
  87
  88                         /*
  89                          * We keep one window "ahead" of the other side, and
  90                          * will wait for an ACK only on the next one
  91                          */
  92                         if (count == 32)
  93                                 continue;
  94                         if (get_ack(fd[0], result_sha1)) {
  95                                 flushes = 0;
  96                                 retval = 0;
  97                                 if (verbose)
  98                                         fprintf(stderr, "got ack\n");
  99                                 break;
 100                         }
 101                         flushes--;
 102                 }
 103         }
 104         pclose(revs);
 105         packet_write(fd[1], "done\n");
 106         if (verbose)
 107                 fprintf(stderr, "done\n");
 108         while (flushes) {
 109                 flushes--;
 110                 if (get_ack(fd[0], result_sha1)) {
 111                         if (verbose)
 112                                 fprintf(stderr, "got ack\n");
 113                         return 0;
 114                 }
 115         }
 116         return retval;
 117 }
 118
 119 static struct commit_list *complete = NULL;
 120
 121 static int mark_complete(const char *path, const unsigned char *sha1)
 122 {
 123         struct object *o = parse_object(sha1);
 124
 125         while (o && o->type == tag_type) {
 126                 struct tag *t = (struct tag *) o;
 127                 if (!t->tagged)
 128                         break; /* broken repository */
 129                 o->flags |= COMPLETE;
 130                 o = parse_object(t->tagged->sha1);
 131         }
 132         if (o && o->type == commit_type) {
 133                 struct commit *commit = (struct commit *)o;
 134                 commit->object.flags |= COMPLETE;
 135                 insert_by_date(commit, &complete);
 136         }
 137         return 0;
 138 }
 139
 140 static void mark_recent_complete_commits(unsigned long cutoff)
 141 {
 142         while (complete && cutoff <= complete->item->date) {
 143                 if (verbose)
 144                         fprintf(stderr, "Marking %s as complete\n",
 145                                 sha1_to_hex(complete->item->object.sha1));
 146                 pop_most_recent_commit(&complete, COMPLETE);
 147         }
 148 }
 149
 150 static int everything_local(struct ref *refs)
 151 {
 152         struct ref *ref;
 153         int retval;
 154         unsigned long cutoff = 0;
 155
 156         track_object_refs = 0;
 157         save_commit_buffer = 0;
 158
 159         for (ref = refs; ref; ref = ref->next) {
 160                 struct object *o;
 161
 162                 o = parse_object(ref->old_sha1);
 163                 if (!o)
 164                         continue;
 165
 166                 /* We already have it -- which may mean that we were
 167                  * in sync with the other side at some time after
 168                  * that (it is OK if we guess wrong here).
 169                  */
 170                 if (o->type == commit_type) {
 171                         struct commit *commit = (struct commit *)o;
 172                         if (!cutoff || cutoff < commit->date)
 173                                 cutoff = commit->date;
 174                 }
 175         }
 176
 177         for_each_ref(mark_complete);
 178         if (cutoff)
 179                 mark_recent_complete_commits(cutoff);
 180
 181         for (retval = 1; refs ; refs = refs->next) {
 182                 const unsigned char *remote = refs->old_sha1;
 183                 unsigned char local[20];
 184                 struct object *o;
 185
 186                 o = parse_object(remote);
 187                 if (!o || !(o->flags & COMPLETE)) {
 188                         retval = 0;
 189                         if (!verbose)
 190                                 continue;
 191                         fprintf(stderr,
 192                                 "want %s (%s)\n", sha1_to_hex(remote),
 193                                 refs->name);
 194                         continue;
 195                 }
 196
 197                 memcpy(refs->new_sha1, local, 20);
 198                 if (!verbose)
 199                         continue;
 200                 fprintf(stderr,
 201                         "already have %s (%s)\n", sha1_to_hex(remote),
 202                         refs->name);
 203         }
 204         return retval;
 205 }
 206
 207 static int fetch_pack(int fd[2], int nr_match, char **match)
 208 {
 209         struct ref *ref;
 210         unsigned char sha1[20];
 211         int status;
 212         pid_t pid;
 213
 214         get_remote_heads(fd[0], &ref, nr_match, match, 1);
 215         if (!ref) {
 216                 packet_flush(fd[1]);
 217                 die("no matching remote head");
 218         }
 219         if (everything_local(ref)) {
 220                 packet_flush(fd[1]);
 221                 goto all_done;
 222         }
 223         if (find_common(fd, sha1, ref) < 0)
 224                 fprintf(stderr, "warning: no common commits\n");
 225         pid = fork();
 226         if (pid < 0)
 227                 die("git-fetch-pack: unable to fork off git-unpack-objects");
 228         if (!pid) {
 229                 dup2(fd[0], 0);
 230                 close(fd[0]);
 231                 close(fd[1]);
 232                 execlp("git-unpack-objects", "git-unpack-objects",
 233                        quiet ? "-q" : NULL, NULL);
 234                 die("git-unpack-objects exec failed");
 235         }
 236         close(fd[0]);
 237         close(fd[1]);
 238         while (waitpid(pid, &status, 0) < 0) {
 239                 if (errno != EINTR)
 240                         die("waiting for git-unpack-objects: %s", strerror(errno));
 241         }
 242         if (WIFEXITED(status)) {
 243                 int code = WEXITSTATUS(status);
 244                 if (code)
 245                         die("git-unpack-objects died with error code %d", code);
 246 all_done:
 247                 while (ref) {
 248                         printf("%s %s\n",
 249                                sha1_to_hex(ref->old_sha1), ref->name);
 250                         ref = ref->next;
 251                 }
 252                 return 0;
 253         }
 254         if (WIFSIGNALED(status)) {
 255                 int sig = WTERMSIG(status);
 256                 die("git-unpack-objects died of signal %d", sig);
 257         }
 258         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 259 }
 260
 261 int main(int argc, char **argv)
 262 {
 263         int i, ret, nr_heads;
 264         char *dest = NULL, **heads;
 265         int fd[2];
 266         pid_t pid;
 267
 268         nr_heads = 0;
 269         heads = NULL;
 270         for (i = 1; i < argc; i++) {
 271                 char *arg = argv[i];
 272
 273                 if (*arg == '-') {
 274                         if (!strncmp("--exec=", arg, 7)) {
 275                                 exec = arg + 7;
 276                                 continue;
 277                         }
 278                         if (!strcmp("-q", arg)) {
 279                                 quiet = 1;
 280                                 continue;
 281                         }
 282                         if (!strcmp("-v", arg)) {
 283                                 verbose = 1;
 284                                 continue;
 285                         }
 286                         usage(fetch_pack_usage);
 287                 }
 288                 dest = arg;
 289                 heads = argv + i + 1;
 290                 nr_heads = argc - i - 1;
 291                 break;
 292         }
 293         if (!dest)
 294                 usage(fetch_pack_usage);
 295         pid = git_connect(fd, dest, exec);
 296         if (pid < 0)
 297                 return 1;
 298         ret = fetch_pack(fd, nr_heads, heads);
 299         close(fd[0]);
 300         close(fd[1]);
 301         finish_connect(pid);
 302         return ret;
 303 }