From: Junio C Hamano <gitster@xxxxxxxxx>
This introduces a new function get_merge_bases_many() which is a natural
extension of two commit merge base computation. It is given one commit
(one) and a set of other commits (twos), and computes the merge base of
one and a merge across other commits.
This is mostly useful to figure out the common ancestor when iterating
over heads during an octopus merge. When making an octopus between
commits A, B, C and D, we first merge tree of A and B, and then try to
merge C with it. If we were making pairwise merge, we would be recording
the tree resulting from the merge between A and B as a commit, say M, and
then the next round we will be computing the merge base between M and C.
o---C...*
/ .
o---B...M
/ .
o---o---A
But during an octopus merge, we actually do not create a commit M. In
order to figure out that the common ancestor to use for this merge,
instead of computing the merge base between C and M, we can call
merge_bases_many() with one set to C and twos containing A and B.
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
commit.c | 56 ++++++++++++++++++++++++++++++++++++++------------------
1 files changed, 38 insertions(+), 18 deletions(-)
diff --git a/commit.c b/commit.c
index 6052ca3..cafed26 100644
--- a/commit.c
+++ b/commit.c
@@ -533,26 +533,34 @@ static struct commit *interesting(struct commit_list *list)
return NULL;
}
-static struct commit_list *merge_bases(struct commit *one, struct commit *two)
+static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
{
struct commit_list *list = NULL;
struct commit_list *result = NULL;
+ int i;
- if (one == two)
- /* We do not mark this even with RESULT so we do not
- * have to clean it up.
- */
- return commit_list_insert(one, &result);
+ for (i = 0; i < n; i++) {
+ if (one == twos[i])
+ /*
+ * We do not mark this even with RESULT so we do not
+ * have to clean it up.
+ */
+ return commit_list_insert(one, &result);
+ }
if (parse_commit(one))
return NULL;
- if (parse_commit(two))
- return NULL;
+ for (i = 0; i < n; i++) {
+ if (parse_commit(twos[i]))
+ return NULL;
+ }
one->object.flags |= PARENT1;
- two->object.flags |= PARENT2;
insert_by_date(one, &list);
- insert_by_date(two, &list);
+ for (i = 0; i < n; i++) {
+ twos[i]->object.flags |= PARENT2;
+ insert_by_date(twos[i], &list);
+ }
while (interesting(list)) {
struct commit *commit;
@@ -627,21 +635,26 @@ struct commit_list *get_octopus_merge_bases(struct commit_list *in)
return ret;
}
-struct commit_list *get_merge_bases(struct commit *one,
- struct commit *two, int cleanup)
+struct commit_list *get_merge_bases_many(struct commit *one,
+ int n,
+ struct commit **twos,
+ int cleanup)
{
struct commit_list *list;
struct commit **rslt;
struct commit_list *result;
int cnt, i, j;
- result = merge_bases(one, two);
- if (one == two)
- return result;
+ result = merge_bases_many(one, n, twos);
+ for (i = 0; i < n; i++) {
+ if (one == twos[i])
+ return result;
+ }
if (!result || !result->next) {
if (cleanup) {
clear_commit_marks(one, all_flags);
- clear_commit_marks(two, all_flags);
+ for (i = 0; i < n; i++)
+ clear_commit_marks(twos[i], all_flags);
}
return result;
}
@@ -659,12 +672,13 @@ struct commit_list *get_merge_bases(struct commit *one,
free_commit_list(result);
clear_commit_marks(one, all_flags);
- clear_commit_marks(two, all_flags);
+ for (i = 0; i < n; i++)
+ clear_commit_marks(twos[i], all_flags);
for (i = 0; i < cnt - 1; i++) {
for (j = i+1; j < cnt; j++) {
if (!rslt[i] || !rslt[j])
continue;
- result = merge_bases(rslt[i], rslt[j]);
+ result = merge_bases_many(rslt[i], 1, &rslt[j]);
clear_commit_marks(rslt[i], all_flags);
clear_commit_marks(rslt[j], all_flags);
for (list = result; list; list = list->next) {
@@ -686,6 +700,12 @@ struct commit_list *get_merge_bases(struct commit *one,
return result;
}
+struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
+ int cleanup)
+{
+ return get_merge_bases_many(one, 1, &two, cleanup);
+}
+
int in_merge_bases(struct commit *commit, struct commit **reference, int num)
{
struct commit_list *bases, *b;
--
1.5.6
--
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