Andrew's git - gitweb.git/blob - 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
  10static const char builtin_get_tar_commit_id_usage[] =
  11"git get-tar-commit-id";
  12
  13/* ustar header + extended global header content */
  14#define RECORDSIZE      (512)
  15#define HEADERSIZE (2 * RECORDSIZE)
  16
  17int 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        const char *comment;
  23        ssize_t n;
  24        long len;
  25        char *end;
  26
  27        if (argc != 1)
  28                usage(builtin_get_tar_commit_id_usage);
  29
  30        n = read_in_full(0, buffer, HEADERSIZE);
  31        if (n < 0)
  32                die_errno("git get-tar-commit-id: read error");
  33        if (n != HEADERSIZE)
  34                die_errno("git get-tar-commit-id: EOF before reading tar header");
  35        if (header->typeflag[0] != 'g')
  36                return 1;
  37
  38        len = strtol(content, &end, 10);
  39        if (errno == ERANGE || end == content || len < 0)
  40                return 1;
  41        if (!skip_prefix(end, " comment=", &comment))
  42                return 1;
  43        len -= comment - content;
  44        if (len < 1 || !(len % 2) ||
  45            hash_algo_by_length((len - 1) / 2) == GIT_HASH_UNKNOWN)
  46                return 1;
  47
  48        if (write_in_full(1, comment, len) < 0)
  49                die_errno("git get-tar-commit-id: write error");
  50
  51        return 0;
  52}