write-tree.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7
   8 static int check_valid_sha1(unsigned char *sha1)
   9 {
  10         char *filename = sha1_file_name(sha1);
  11         int ret;
  12
  13         /* If we were anal, we'd check that the sha1 of the contents actually matches */
  14         ret = access(filename, R_OK);
  15         if (ret)
  16                 perror(filename);
  17         return ret;
  18 }
  19
  20 static int prepend_integer(char *buffer, unsigned val, int i)
  21 {
  22         buffer[--i] = '\0';
  23         do {
  24                 buffer[--i] = '0' + (val % 10);
  25                 val /= 10;
  26         } while (val);
  27         return i;
  28 }
  29
  30 #define ORIG_OFFSET (40)        /* Enough space to add the header of "tree <size>\0" */
  31
  32 int main(int argc, char **argv)
  33 {
  34         unsigned long size, offset, val;
  35         int i, entries = read_cache();
  36         char *buffer;
  37
  38         if (entries <= 0) {
  39                 fprintf(stderr, "No file-cache to create a tree of\n");
  40                 exit(1);
  41         }
  42
  43         /* Guess at an initial size */
  44         size = entries * 40 + 400;
  45         buffer = malloc(size);
  46         offset = ORIG_OFFSET;
  47
  48         for (i = 0; i < entries; i++) {
  49                 struct cache_entry *ce = active_cache[i];
  50                 if (check_valid_sha1(ce->sha1) < 0)
  51                         exit(1);
  52                 if (offset + ce->namelen + 60 > size) {
  53                         size = alloc_nr(offset + ce->namelen + 60);
  54                         buffer = realloc(buffer, size);
  55                 }
  56                 offset += sprintf(buffer + offset, "%o %s", ce->st_mode, ce->name);
  57                 buffer[offset++] = 0;
  58                 memcpy(buffer + offset, ce->sha1, 20);
  59                 offset += 20;
  60         }
  61
  62         i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
  63         i -= 5;
  64         memcpy(buffer+i, "tree ", 5);
  65
  66         buffer += i;
  67         offset -= i;
  68
  69         write_sha1_file(buffer, offset);
  70         return 0;
  71 }