merge-base finds one of the best common ancestors of a pair of commits. In
particular, it finds one of the ones which is fewest commits away from the
further of the heads.
Signed-Off-By: Daniel Barkalow <[EMAIL PROTECTED]>
Index: Makefile
===================================================================
--- 45f926575d2c44072bfcf2317dbf3f0fbb513a4e/Makefile (mode:100644
sha1:346e3850de026485802e41e16a1180be2df85e4a)
+++ 7d806c2d3be8f87d3d4d87e5254500d7fc24476b/Makefile (mode:100644
sha1:0e84e3cd12f836602b420c197e08fabefe975493)
@@ -14,7 +17,7 @@
PROG= update-cache show-diff init-db write-tree read-tree commit-tree \
cat-file fsck-cache checkout-cache diff-tree rev-tree show-files \
- check-files ls-tree
+ check-files ls-tree merge-base
SCRIPT= parent-id tree-id git gitXnormid.sh gitadd.sh gitaddremote.sh \
gitcommit.sh gitdiff-do gitdiff.sh gitlog.sh gitls.sh gitlsobj.sh \
Index: merge-base.c
===================================================================
--- /dev/null (tree:45f926575d2c44072bfcf2317dbf3f0fbb513a4e)
+++ 7d806c2d3be8f87d3d4d87e5254500d7fc24476b/merge-base.c (mode:100644
sha1:ee979c7532cbdf823e9930993b0dd8f97aadb21f)
@@ -0,0 +1,95 @@
+#include <stdlib.h>
+#include "cache.h"
+#include "revision.h"
+
+static struct revision *process_list(struct parent **list_p, int this_mark,
+ int other_mark)
+{
+ struct parent *parent, *temp;
+ struct parent *posn = *list_p;
+ *list_p = NULL;
+ while (posn) {
+ parse_commit_object(posn->parent);
+ if (posn->parent->flags & this_mark) {
+ /*
+ printf("%d already seen %s %x\n",
+ this_mark
+ sha1_to_hex(posn->parent->sha1),
+ posn->parent->flags);
+ */
+ /* do nothing; this indicates that this side
+ * split and reformed, and we only need to
+ * mark it once.
+ */
+ } else if (posn->parent->flags & other_mark) {
+ return posn->parent;
+ } else {
+ /*
+ printf("%d based on %s\n",
+ this_mark,
+ sha1_to_hex(posn->parent->sha1));
+ */
+ posn->parent->flags |= this_mark;
+
+ parent = posn->parent->parent;
+ while (parent) {
+ temp = malloc(sizeof(struct parent));
+ temp->next = *list_p;
+ temp->parent = parent->parent;
+ *list_p = temp;
+ parent = parent->next;
+ }
+ }
+ posn = posn->next;
+ }
+ return NULL;
+}
+
+struct revision *common_ancestor(struct revision *rev1, struct revision *rev2)
+{
+ struct parent *rev1list = malloc(sizeof(struct parent));
+ struct parent *rev2list = malloc(sizeof(struct parent));
+
+ rev1list->parent = rev1;
+ rev1list->next = NULL;
+
+ rev2list->parent = rev2;
+ rev2list->next = NULL;
+
+ while (rev1list || rev2list) {
+ struct revision *ret;
+ ret = process_list(&rev1list, 0x1, 0x2);
+ if (ret) {
+ /* XXXX free lists */
+ return ret;
+ }
+ ret = process_list(&rev2list, 0x2, 0x1);
+ if (ret) {
+ /* XXXX free lists */
+ return ret;
+ }
+ }
+ return NULL;
+}
+
+int main(int argc, char **argv)
+{
+ struct revision *rev1, *rev2, *ret;
+ unsigned char rev1key[20], rev2key[20];
+
+ if (argc != 3 ||
+ get_sha1_hex(argv[1], rev1key) ||
+ get_sha1_hex(argv[2], rev2key)) {
+ usage("merge-base <commit-id> <commit-id>");
+ }
+ rev1 = lookup_rev(rev1key);
+ rev2 = lookup_rev(rev2key);
+ ret = common_ancestor(rev1, rev2);
+ if (ret) {
+ printf("%s\n", sha1_to_hex(ret->sha1));
+ return 0;
+ } else {
+ return 1;
+ }
+
+}
-
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
