fetch-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include <sys/wait.h>
   5
   6 static int quiet;
   7 static int verbose;
   8 static const char fetch_pack_usage[] =
   9 "git-fetch-pack [-q] [-v] [--exec=upload-pack] [host:]directory <refs>...";
  10 static const char *exec = "git-upload-pack";
  11
  12 static int find_common(int fd[2], unsigned char *result_sha1,
  13                        struct ref *refs)
  14 {
  15         int fetching;
  16         static char line[1000];
  17         int count = 0, flushes = 0, retval;
  18         FILE *revs;
  19
  20         revs = popen("git-rev-list $(git-rev-parse --all)", "r");
  21         if (!revs)
  22                 die("unable to run 'git-rev-list'");
  23
  24         fetching = 0;
  25         for ( ; refs ; refs = refs->next) {
  26                 unsigned char *remote = refs->old_sha1;
  27                 unsigned char *local = refs->new_sha1;
  28
  29                 if (!memcmp(remote, local, 20))
  30                         continue;
  31                 packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
  32                 fetching++;
  33         }
  34         packet_flush(fd[1]);
  35         if (!fetching)
  36                 return 1;
  37         flushes = 1;
  38         retval = -1;
  39         while (fgets(line, sizeof(line), revs) != NULL) {
  40                 unsigned char sha1[20];
  41                 if (get_sha1_hex(line, sha1))
  42                         die("git-fetch-pack: expected object name, got crud");
  43                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
  44                 if (verbose)
  45                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
  46                 if (!(31 & ++count)) {
  47                         packet_flush(fd[1]);
  48                         flushes++;
  49
  50                         /*
  51                          * We keep one window "ahead" of the other side, and
  52                          * will wait for an ACK only on the next one
  53                          */
  54                         if (count == 32)
  55                                 continue;
  56                         if (get_ack(fd[0], result_sha1)) {
  57                                 flushes = 0;
  58                                 retval = 0;
  59                                 if (verbose)
  60                                         fprintf(stderr, "got ack\n");
  61                                 break;
  62                         }
  63                         flushes--;
  64                 }
  65         }
  66         pclose(revs);
  67         packet_write(fd[1], "done\n");
  68         if (verbose)
  69                 fprintf(stderr, "done\n");
  70         while (flushes) {
  71                 flushes--;
  72                 if (get_ack(fd[0], result_sha1)) {
  73                         if (verbose)
  74                                 fprintf(stderr, "got ack\n");
  75                         return 0;
  76                 }
  77         }
  78         return retval;
  79 }
  80
  81 static int everything_local(struct ref *refs)
  82 {
  83         int retval;
  84
  85         for (retval = 1; refs ; refs = refs->next) {
  86                 const unsigned char *remote = refs->old_sha1;
  87                 unsigned char local[20];
  88
  89                 if (read_ref(git_path("%s", refs->name), local) < 0 ||
  90                     memcmp(remote, local, 20)) {
  91                         retval = 0;
  92                         if (!verbose)
  93                                 continue;
  94                         fprintf(stderr,
  95                                 "want %s (%s)\n", sha1_to_hex(remote),
  96                                 refs->name);
  97                         continue;
  98                 }
  99
 100                 memcpy(refs->new_sha1, local, 20);
 101                 if (!verbose)
 102                         continue;
 103                 fprintf(stderr,
 104                         "already have %s (%s)\n", sha1_to_hex(remote),
 105                         refs->name);
 106         }
 107         return retval;
 108 }
 109
 110 static int fetch_pack(int fd[2], int nr_match, char **match)
 111 {
 112         struct ref *ref;
 113         unsigned char sha1[20];
 114         int status;
 115         pid_t pid;
 116
 117         get_remote_heads(fd[0], &ref, nr_match, match, 1);
 118         if (!ref) {
 119                 packet_flush(fd[1]);
 120                 die("no matching remote head");
 121         }
 122         if (everything_local(ref)) {
 123                 packet_flush(fd[1]);
 124                 goto all_done;
 125         }
 126         if (find_common(fd, sha1, ref) < 0)
 127                 fprintf(stderr, "warning: no common commits\n");
 128         pid = fork();
 129         if (pid < 0)
 130                 die("git-fetch-pack: unable to fork off git-unpack-objects");
 131         if (!pid) {
 132                 dup2(fd[0], 0);
 133                 close(fd[0]);
 134                 close(fd[1]);
 135                 execlp("git-unpack-objects", "git-unpack-objects",
 136                        quiet ? "-q" : NULL, NULL);
 137                 die("git-unpack-objects exec failed");
 138         }
 139         close(fd[0]);
 140         close(fd[1]);
 141         while (waitpid(pid, &status, 0) < 0) {
 142                 if (errno != EINTR)
 143                         die("waiting for git-unpack-objects: %s", strerror(errno));
 144         }
 145         if (WIFEXITED(status)) {
 146                 int code = WEXITSTATUS(status);
 147                 if (code)
 148                         die("git-unpack-objects died with error code %d", code);
 149 all_done:
 150                 while (ref) {
 151                         printf("%s %s\n",
 152                                sha1_to_hex(ref->old_sha1), ref->name);
 153                         ref = ref->next;
 154                 }
 155                 return 0;
 156         }
 157         if (WIFSIGNALED(status)) {
 158                 int sig = WTERMSIG(status);
 159                 die("git-unpack-objects died of signal %d", sig);
 160         }
 161         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 162 }
 163
 164 int main(int argc, char **argv)
 165 {
 166         int i, ret, nr_heads;
 167         char *dest = NULL, **heads;
 168         int fd[2];
 169         pid_t pid;
 170
 171         nr_heads = 0;
 172         heads = NULL;
 173         for (i = 1; i < argc; i++) {
 174                 char *arg = argv[i];
 175
 176                 if (*arg == '-') {
 177                         if (!strncmp("--exec=", arg, 7)) {
 178                                 exec = arg + 7;
 179                                 continue;
 180                         }
 181                         if (!strcmp("-q", arg)) {
 182                                 quiet = 1;
 183                                 continue;
 184                         }
 185                         if (!strcmp("-v", arg)) {
 186                                 verbose = 1;
 187                                 continue;
 188                         }
 189                         usage(fetch_pack_usage);
 190                 }
 191                 dest = arg;
 192                 heads = argv + i + 1;
 193                 nr_heads = argc - i - 1;
 194                 break;
 195         }
 196         if (!dest)
 197                 usage(fetch_pack_usage);
 198         pid = git_connect(fd, dest, exec);
 199         if (pid < 0)
 200                 return 1;
 201         ret = fetch_pack(fd, nr_heads, heads);
 202         close(fd[0]);
 203         close(fd[1]);
 204         finish_connect(pid);
 205         return ret;
 206 }