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-rw-r--r--combine-diff.c39
1 files changed, 37 insertions, 2 deletions
diff --git a/combine-diff.c b/combine-diff.c
index 243f96775a..0cc18feb60 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -523,6 +523,30 @@ static void dump_sline(struct sline *sline, int cnt, int num_parent)
}
}
+static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
+ int i, int j)
+{
+ /* We have already examined parent j and we know parent i
+ * and parent j are the same, so reuse the combined result
+ * of parent j for parent i.
+ */
+ unsigned long lno, imask, jmask;
+ imask = (1UL<<i);
+ jmask = (1UL<<j);
+
+ for (lno = 0; lno < cnt; lno++) {
+ struct lline *ll = sline->lost_head;
+ while (ll) {
+ if (ll->parent_map & jmask)
+ ll->parent_map |= imask;
+ ll = ll->next;
+ }
+ if (!(sline->flag & jmask))
+ sline->flag &= ~imask;
+ sline++;
+ }
+}
+
int show_combined_diff(struct combine_diff_path *elem, int num_parent,
int dense, const char *header, int show_empty)
{
@@ -596,8 +620,19 @@ int show_combined_diff(struct combine_diff_path *elem, int num_parent,
sline[cnt-1].flag = (1UL<<num_parent) - 1;
}
- for (i = 0; i < num_parent; i++)
- combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
+ for (i = 0; i < num_parent; i++) {
+ int j;
+ for (j = 0; j < i; j++) {
+ if (!memcmp(elem->parent_sha1[i],
+ elem->parent_sha1[j], 20)) {
+ reuse_combine_diff(sline, cnt, i, j);
+ break;
+ }
+ }
+ if (i <= j)
+ combine_diff(elem->parent_sha1[i], ourtmp, sline,
+ cnt, i);
+ }
show_hunks = make_hunks(sline, cnt, num_parent, dense);