Early exit on VM String.replaceAll
Change-Id: I2578200444935d221fab7f9fb4d515a9b2e75937
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97145
Commit-Queue: Stephen Adams <sra@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
diff --git a/runtime/lib/string_patch.dart b/runtime/lib/string_patch.dart
index 0fcb35c..e75284a 100644
--- a/runtime/lib/string_patch.dart
+++ b/runtime/lib/string_patch.dart
@@ -628,10 +628,13 @@
String replaceAll(Pattern pattern, String replacement) {
if (pattern == null) throw new ArgumentError.notNull("pattern");
if (replacement == null) throw new ArgumentError.notNull("replacement");
- List matches = [];
- int length = 0;
- int replacementLength = replacement.length;
+
int startIndex = 0;
+ // String fragments that replace the the prefix [this] up to [startIndex].
+ List matches = [];
+ int length = 0; // Length of all fragments.
+ int replacementLength = replacement.length;
+
if (replacementLength == 0) {
for (Match match in pattern.allMatches(this)) {
length += _addReplaceSlice(matches, startIndex, match.start);
@@ -645,6 +648,8 @@
startIndex = match.end;
}
}
+ // No match, or a zero-length match at start with zero-length replacement.
+ if (startIndex == 0 && length == 0) return this;
length += _addReplaceSlice(matches, startIndex, this.length);
bool replacementIsOneByte = replacement._isOneByte;
if (replacementIsOneByte &&
