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 static int write_tree(struct cache_entry **cachep, int maxentries, const char *base, int baselen, unsigned char *returnsha1)
  33 {
  34         unsigned char subdir_sha1[20];
  35         unsigned long size, offset;
  36         char *buffer;
  37         int i, nr;
  38
  39         /* Guess at some random initial size */
  40         size = 8192;
  41         buffer = malloc(size);
  42         offset = ORIG_OFFSET;
  43
  44         nr = 0;
  45         do {
  46                 struct cache_entry *ce = cachep[nr];
  47                 const char *pathname = ce->name, *filename, *dirname;
  48                 int pathlen = ce->namelen, entrylen;
  49                 unsigned char *sha1;
  50                 unsigned int mode;
  51
  52                 /* Did we hit the end of the directory? Return how many we wrote */
  53                 if (baselen >= pathlen || memcmp(base, pathname, baselen))
  54                         break;
  55
  56                 sha1 = ce->sha1;
  57                 mode = ce->st_mode;
  58
  59                 /* Do we have _further_ subdirectories? */
  60                 filename = pathname + baselen;
  61                 dirname = strchr(filename, '/');
  62                 if (dirname) {
  63                         int subdir_written;
  64
  65                         subdir_written = write_tree(cachep + nr, maxentries - nr, pathname, dirname-pathname+1, subdir_sha1);
  66                         nr += subdir_written;
  67
  68                         /* Now we need to write out the directory entry into this tree.. */
  69                         mode = S_IFDIR;
  70                         pathlen = dirname - pathname;
  71
  72                         /* ..but the directory entry doesn't count towards the total count */
  73                         nr--;
  74                         sha1 = subdir_sha1;
  75                 }
  76
  77                 if (check_valid_sha1(sha1) < 0)
  78                         exit(1);
  79
  80                 entrylen = pathlen - baselen;
  81                 if (offset + entrylen + 100 > size) {
  82                         size = alloc_nr(offset + entrylen + 100);
  83                         buffer = realloc(buffer, size);
  84                 }
  85                 offset += sprintf(buffer + offset, "%o %.*s", mode, entrylen, filename);
  86                 buffer[offset++] = 0;
  87                 memcpy(buffer + offset, sha1, 20);
  88                 offset += 20;
  89                 nr++;
  90         } while (nr < maxentries);
  91
  92         i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
  93         i -= 5;
  94         memcpy(buffer+i, "tree ", 5);
  95
  96         buffer += i;
  97         offset -= i;
  98
  99         write_sha1_file(buffer, offset, returnsha1);
 100         return nr;
 101 }
 102
 103 int main(int argc, char **argv)
 104 {
 105         int entries = read_cache();
 106         unsigned char sha1[20];
 107
 108         if (entries <= 0)
 109                 usage("no cache contents to write");
 110         if (write_tree(active_cache, entries, "", 0, sha1) != entries)
 111                 usage("write-tree: internal error");
 112         printf("%s\n", sha1_to_hex(sha1));
 113         return 0;
 114 }