Diff without asking xdiff for a minimal result

XDF_NEED_MINIMAL turns off the cost limit in xdiff, so a file whose
lines were reordered took time quadratic in its length: 2.1 s for one of
40000 lines, now 38 ms. Git leaves it off by default as well.

1 file changed, 3 insertions, 1 deletion

diff --git a/source/shared.c b/source/shared.cindex 51c92d4..0bd9fe3 100644--- a/source/shared.c+++ b/source/shared.c@@ -435,7 +435,9 @@ int cgit_diff_files(const struct object_id *old_oid, const struct object_id *new 	memset(&diff_params, 0, sizeof(diff_params)); 	memset(&emit_params, 0, sizeof(emit_params)); 	memset(&emit_cb, 0, sizeof(emit_cb));-	diff_params.flags = XDF_NEED_MINIMAL;+	// Without XDF_NEED_MINIMAL, as git diffs by default: on a file whose+	// lines were reordered, a minimal diff costs time quadratic in its+	// length. 	if (ignorews) 		diff_params.flags |= XDF_IGNORE_WHITESPACE; 	emit_params.ctxlen = context > 0 ? context : DEFAULT_DIFF_CONTEXT;
diff --git a/source/shared.c b/source/shared.c
index 51c92d4..0bd9fe3 100644
--- a/source/shared.c
+++ b/source/shared.c
@@ -435,7 +435,9 @@ int cgit_diff_files(const struct object_id *old_oid, const struct object_id *new
 	memset(&diff_params, 0, sizeof(diff_params));
 	memset(&emit_params, 0, sizeof(emit_params));
 	memset(&emit_cb, 0, sizeof(emit_cb));
-	diff_params.flags = XDF_NEED_MINIMAL;
+	// Without XDF_NEED_MINIMAL, as git diffs by default: on a file whose
+	// lines were reordered, a minimal diff costs time quadratic in its
+	// length.
 	if (ignorews)
 		diff_params.flags |= XDF_IGNORE_WHITESPACE;
 	emit_params.ctxlen = context > 0 ? context : DEFAULT_DIFF_CONTEXT;