write-tree.c

   1 #include "cache.h"
   2
   3 static int check_valid_sha1(unsigned char *sha1)
   4 {
   5         char *filename = sha1_file_name(sha1);
   6         int ret;
   7
   8         /* If we were anal, we'd check that the sha1 of the contents actually matches */
   9         ret = access(filename, R_OK);
  10         if (ret)
  11                 perror(filename);
  12         return ret;
  13 }
  14
  15 static int prepend_integer(char *buffer, unsigned val, int i)
  16 {
  17         buffer[--i] = '\0';
  18         do {
  19                 buffer[--i] = '0' + (val % 10);
  20                 val /= 10;
  21         } while (val);
  22         return i;
  23 }
  24
  25 #define ORIG_OFFSET (40)        /* Enough space to add the header of "tree <size>\0" */
  26
  27 int main(int argc, char **argv)
  28 {
  29         unsigned long size, offset, val;
  30         int i, entries = read_cache();
  31         char *buffer;
  32
  33         if (entries <= 0) {
  34                 fprintf(stderr, "No file-cache to create a tree of\n");
  35                 exit(1);
  36         }
  37
  38         /* Guess at an initial size */
  39         size = entries * 40 + 400;
  40         buffer = malloc(size);
  41         offset = ORIG_OFFSET;
  42
  43         for (i = 0; i < entries; i++) {
  44                 struct cache_entry *ce = active_cache[i];
  45                 if (check_valid_sha1(ce->sha1) < 0)
  46                         exit(1);
  47                 if (offset + ce->namelen + 60 > size) {
  48                         size = alloc_nr(offset + ce->namelen + 60);
  49                         buffer = realloc(buffer, size);
  50                 }
  51                 offset += sprintf(buffer + offset, "%o %s", ce->st_mode, ce->name);
  52                 buffer[offset++] = 0;
  53                 memcpy(buffer + offset, ce->sha1, 20);
  54                 offset += 20;
  55         }
  56
  57         i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
  58         i -= 5;
  59         memcpy(buffer+i, "tree ", 5);
  60
  61         buffer += i;
  62         offset -= i;
  63
  64         write_sha1_file(buffer, offset);
  65         return 0;
  66 }