merge-base.c

   1 #include "cache.h"
   2 #include "revision.h"
   3
   4 /*
   5  * This is stupid. We could have much better heurstics, I bet.
   6  */
   7 static int better(struct revision *new, struct revision *old)
   8 {
   9         return new->date > old->date;
  10 }
  11
  12 static struct revision *common_parent(struct revision *rev1, struct revision *rev2)
  13 {
  14         int i;
  15         struct revision *best = NULL;
  16
  17         mark_reachable(rev1, 1);
  18         mark_reachable(rev2, 2);
  19         for (i = 0; i < nr_revs ;i++) {
  20                 struct revision *rev = revs[i];
  21                 if ((rev->flags & 3) != 3)
  22                         continue;
  23                 if (!best) {
  24                         best = rev;
  25                         continue;
  26                 }
  27                 if (better(rev, best))
  28                         best = rev;
  29         }
  30         return best;
  31 }
  32
  33 int main(int argc, char **argv)
  34 {
  35         unsigned char rev1[20], rev2[20];
  36         struct revision *common;
  37
  38         if (argc != 3 || get_sha1_hex(argv[1], rev1) || get_sha1_hex(argv[2], rev2))
  39                 usage("merge-base <commit1> <commit2>");
  40
  41         /*
  42          * We will eventually want to include a revision cache file
  43          * that "rev-tree.c" has generated, since this is going to
  44          * otherwise be quite expensive for big trees..
  45          *
  46          * That's some time off, though, and in the meantime we know
  47          * that we have a solution to the eventual expense.
  48          */
  49         parse_commit(rev1);
  50         parse_commit(rev2);
  51
  52         common = common_parent(lookup_rev(rev1), lookup_rev(rev2));
  53         if (!common)
  54                 die("no common parent found");
  55         printf("%s\n", sha1_to_hex(common->sha1));
  56         return 0;
  57 }