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 const char fetch_pack_usage[] = "git-fetch-pack [-q] [--exec=upload-pack] [host:]directory [heads]* < mycommitlist";
   8 static const char *exec = "git-upload-pack";
   9
  10 static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *remote)
  11 {
  12         static char line[1000];
  13         int count = 0, flushes = 0, retval;
  14         FILE *revs;
  15
  16         revs = popen("git-rev-list $(git-rev-parse --all)", "r");
  17         if (!revs)
  18                 die("unable to run 'git-rev-list'");
  19         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
  20         packet_flush(fd[1]);
  21         flushes = 1;
  22         retval = -1;
  23         while (fgets(line, sizeof(line), revs) != NULL) {
  24                 unsigned char sha1[20];
  25                 if (get_sha1_hex(line, sha1))
  26                         die("git-fetch-pack: expected object name, got crud");
  27                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
  28                 if (!(31 & ++count)) {
  29                         packet_flush(fd[1]);
  30                         flushes++;
  31
  32                         /*
  33                          * We keep one window "ahead" of the other side, and
  34                          * will wait for an ACK only on the next one
  35                          */
  36                         if (count == 32)
  37                                 continue;
  38                         if (get_ack(fd[0], result_sha1)) {
  39                                 flushes = 0;
  40                                 retval = 0;
  41                                 break;
  42                         }
  43                         flushes--;
  44                 }
  45         }
  46         pclose(revs);
  47         packet_write(fd[1], "done\n");
  48         while (flushes) {
  49                 flushes--;
  50                 if (get_ack(fd[0], result_sha1))
  51                         return 0;
  52         }
  53         return retval;
  54 }
  55
  56 /*
  57  * Eventually we'll want to be able to fetch multiple heads.
  58  *
  59  * Right now we'll just require a single match.
  60  */
  61 static int fetch_pack(int fd[2], int nr_match, char **match)
  62 {
  63         struct ref *ref;
  64         unsigned char sha1[20];
  65         int status;
  66         pid_t pid;
  67
  68         get_remote_heads(fd[0], &ref, nr_match, match);
  69         if (!ref) {
  70                 packet_flush(fd[1]);
  71                 die("no matching remote head");
  72         }
  73         if (ref->next) {
  74                 packet_flush(fd[1]);
  75                 die("multiple remote heads");
  76         }
  77         if (find_common(fd, sha1, ref->old_sha1) < 0)
  78                 die("git-fetch-pack: no common commits");
  79         pid = fork();
  80         if (pid < 0)
  81                 die("git-fetch-pack: unable to fork off git-unpack-objects");
  82         if (!pid) {
  83                 dup2(fd[0], 0);
  84                 close(fd[0]);
  85                 close(fd[1]);
  86                 execlp("git-unpack-objects", "git-unpack-objects",
  87                        quiet ? "-q" : NULL, NULL);
  88                 die("git-unpack-objects exec failed");
  89         }
  90         close(fd[0]);
  91         close(fd[1]);
  92         while (waitpid(pid, &status, 0) < 0) {
  93                 if (errno != EINTR)
  94                         die("waiting for git-unpack-objects: %s", strerror(errno));
  95         }
  96         if (WIFEXITED(status)) {
  97                 int code = WEXITSTATUS(status);
  98                 if (code)
  99                         die("git-unpack-objects died with error code %d", code);
 100                 puts(sha1_to_hex(ref->old_sha1));
 101                 return 0;
 102         }
 103         if (WIFSIGNALED(status)) {
 104                 int sig = WTERMSIG(status);
 105                 die("git-unpack-objects died of signal %d", sig);
 106         }
 107         die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
 108 }
 109
 110 int main(int argc, char **argv)
 111 {
 112         int i, ret, nr_heads;
 113         char *dest = NULL, **heads;
 114         int fd[2];
 115         pid_t pid;
 116
 117         nr_heads = 0;
 118         heads = NULL;
 119         for (i = 1; i < argc; i++) {
 120                 char *arg = argv[i];
 121
 122                 if (*arg == '-') {
 123                         if (!strncmp("--exec=", arg, 7)) {
 124                                 exec = arg + 7;
 125                                 continue;
 126                         }
 127                         usage(fetch_pack_usage);
 128                 }
 129                 dest = arg;
 130                 heads = argv + i + 1;
 131                 nr_heads = argc - i - 1;
 132                 break;
 133         }
 134         if (!dest)
 135                 usage(fetch_pack_usage);
 136         pid = git_connect(fd, dest, exec);
 137         if (pid < 0)
 138                 return 1;
 139         ret = fetch_pack(fd, nr_heads, heads);
 140         close(fd[0]);
 141         close(fd[1]);
 142         finish_connect(pid);
 143         return ret;
 144 }