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-rw-r--r--xdiff/xmerge.c70
1 files changed, 69 insertions, 1 deletions
diff --git a/xdiff/xmerge.c b/xdiff/xmerge.c
index b83b3348cc..82b3573e7a 100644
--- a/xdiff/xmerge.c
+++ b/xdiff/xmerge.c
@@ -248,10 +248,76 @@ static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
return 0;
}
+static int line_contains_alnum(const char *ptr, long size)
+{
+ while (size--)
+ if (isalnum(*(ptr++)))
+ return 1;
+ return 0;
+}
+
+static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
+{
+ for (; chg; chg--, i++)
+ if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
+ xe->xdf2.recs[i]->size))
+ return 1;
+ return 0;
+}
+
+/*
+ * This function merges m and m->next, marking everything between those hunks
+ * as conflicting, too.
+ */
+static void xdl_merge_two_conflicts(xdmerge_t *m)
+{
+ xdmerge_t *next_m = m->next;
+ m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
+ m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
+ m->next = next_m->next;
+ free(next_m);
+}
+
+/*
+ * If there are less than 3 non-conflicting lines between conflicts,
+ * it appears simpler -- because it takes up less (or as many) lines --
+ * if the lines are moved into the conflicts.
+ */
+static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
+ int simplify_if_no_alnum)
+{
+ int result = 0;
+
+ if (!m)
+ return result;
+ for (;;) {
+ xdmerge_t *next_m = m->next;
+ int begin, end;
+
+ if (!next_m)
+ return result;
+
+ begin = m->i1 + m->chg1;
+ end = next_m->i1;
+
+ if (m->mode != 0 || next_m->mode != 0 ||
+ (end - begin > 3 &&
+ (!simplify_if_no_alnum ||
+ lines_contain_alnum(xe1, begin, end - begin)))) {
+ m = next_m;
+ } else {
+ result++;
+ xdl_merge_two_conflicts(m);
+ }
+ }
+}
+
/*
* level == 0: mark all overlapping changes as conflict
* level == 1: mark overlapping changes as conflict only if not identical
* level == 2: analyze non-identical changes for minimal conflict set
+ * level == 3: analyze non-identical changes for minimal conflict set, but
+ * treat hunks not containing any letter or number as conflicting
*
* returns < 0 on error, == 0 for no conflicts, else number of conflicts
*/
@@ -355,7 +421,9 @@ static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1, const char *name1,
if (!changes)
changes = c;
/* refine conflicts */
- if (level > 1 && xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0) {
+ if (level > 1 &&
+ (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
+ xdl_simplify_non_conflicts(xe1, changes, level > 2) < 0)) {
xdl_cleanup_merge(changes);
return -1;
}