fetch-pack.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3
   4 static const char fetch_pack_usage[] = "git-fetch-pack [host:]directory [heads]* < mycommitlist";
   5 static const char *exec = "git-upload-pack";
   6
   7 static int get_ack(int fd, unsigned char *result_sha1)
   8 {
   9         static char line[1000];
  10         int len = packet_read_line(fd, line, sizeof(line));
  11
  12         if (!len)
  13                 die("git-fetch-pack: expected ACK/NAK, got EOF");
  14         if (line[len-1] == '\n')
  15                 line[--len] = 0;
  16         if (!strcmp(line, "NAK"))
  17                 return 0;
  18         if (!strncmp(line, "ACK ", 3)) {
  19                 if (!get_sha1_hex(line+4, result_sha1))
  20                         return 1;
  21         }
  22         die("git-fetch_pack: expected ACK/NAK, got '%s'", line);
  23 }
  24
  25 static int find_common(int fd[2], unsigned char *result_sha1)
  26 {
  27         static char line[1000];
  28         int count = 0, flushes = 0;
  29
  30         while (fgets(line, sizeof(line), stdin) != NULL) {
  31                 unsigned char sha1[20];
  32                 if (get_sha1_hex(line, sha1))
  33                         die("git-fetch-pack: expected object name, got crud");
  34                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
  35                 if (!(31 & ++count)) {
  36                         packet_flush(fd[1]);
  37                         flushes++;
  38
  39                         /*
  40                          * We keep one window "ahead" of the other side, and
  41                          * will wait for an ACK only on the next one
  42                          */
  43                         if (count == 32)
  44                                 continue;
  45                         if (get_ack(fd[0], result_sha1))
  46                                 return 0;
  47                         flushes--;
  48                 }
  49         }
  50         flushes++;
  51         packet_flush(fd[1]);
  52         while (flushes) {
  53                 flushes--;
  54                 if (get_ack(fd[0], result_sha1))
  55                         return 0;
  56         }
  57         return -1;
  58 }
  59
  60 static int get_remote_heads(int fd, int nr_match, char **match)
  61 {
  62         for (;;) {
  63                 static char line[1000];
  64                 unsigned char sha1[20];
  65                 char *refname;
  66                 int len;
  67
  68                 len = packet_read_line(fd, line, sizeof(line));
  69                 if (!len)
  70                         break;
  71                 if (line[len-1] == '\n')
  72                         line[--len] = 0;
  73                 if (len < 42 || get_sha1_hex(line, sha1))
  74                         die("git-fetch-pack: protocol error - expected ref descriptor, got '%sä'", line);
  75                 refname = line+41;
  76                 if (nr_match && !path_match(refname, nr_match, match))
  77                         continue;
  78                 printf("%s %s\n", sha1_to_hex(sha1), refname);
  79         }
  80         return 0;
  81 }
  82
  83 static int fetch_pack(int fd[2], int nr_match, char **match)
  84 {
  85         unsigned char sha1[20];
  86
  87         get_remote_heads(fd[0], nr_match, match);
  88         if (find_common(fd, sha1) < 0)
  89                 die("git-fetch-pack: no common commits");
  90         printf("common commit: %s\n", sha1_to_hex(sha1));
  91         return 0;
  92 }
  93
  94 int main(int argc, char **argv)
  95 {
  96         int i, ret, nr_heads;
  97         char *dest = NULL, **heads;
  98         int fd[2];
  99         pid_t pid;
 100
 101         nr_heads = 0;
 102         heads = NULL;
 103         for (i = 1; i < argc; i++) {
 104                 char *arg = argv[i];
 105
 106                 if (*arg == '-') {
 107                         /* Arguments go here */
 108                         usage(fetch_pack_usage);
 109                 }
 110                 dest = arg;
 111                 heads = argv + i + 1;
 112                 nr_heads = argc - i - 1;
 113                 break;
 114         }
 115         if (!dest)
 116                 usage(fetch_pack_usage);
 117         pid = git_connect(fd, dest, exec);
 118         if (pid < 0)
 119                 return 1;
 120         ret = fetch_pack(fd, nr_heads, heads);
 121         close(fd[0]);
 122         close(fd[1]);
 123         finish_connect(pid);
 124         return ret;
 125 }