builtin/get-tar-commit-id.c

   1 /*
   2  * Copyright (c) 2005, 2006 Rene Scharfe
   3  */
   4 #include "cache.h"
   5 #include "commit.h"
   6 #include "tar.h"
   7 #include "builtin.h"
   8 #include "quote.h"
   9
  10 static const char builtin_get_tar_commit_id_usage[] =
  11 "git get-tar-commit-id < <tarfile>";
  12
  13 /* ustar header + extended global header content */
  14 #define RECORDSIZE      (512)
  15 #define HEADERSIZE (2 * RECORDSIZE)
  16
  17 int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
  18 {
  19         char buffer[HEADERSIZE];
  20         struct ustar_header *header = (struct ustar_header *)buffer;
  21         char *content = buffer + RECORDSIZE;
  22         ssize_t n;
  23
  24         if (argc != 1)
  25                 usage(builtin_get_tar_commit_id_usage);
  26
  27         n = read_in_full(0, buffer, HEADERSIZE);
  28         if (n < HEADERSIZE)
  29                 die("git get-tar-commit-id: read error");
  30         if (header->typeflag[0] != 'g')
  31                 return 1;
  32         if (memcmp(content, "52 comment=", 11))
  33                 return 1;
  34
  35         n = write_in_full(1, content + 11, 41);
  36         if (n < 41)
  37                 die_errno("git get-tar-commit-id: write error");
  38
  39         return 0;
  40 }