Specialize string equality for various string classes. Implement intrinsics for string equal…

runtime/lib/string_patch.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class String {
   /* patch */ factory String.fromCharCodes(Iterable<int> charCodes) {
     return _StringBase.createFromCharCodes(charCodes);
   }
 }
 
@@ skipping 71 matching lines @@
 
   bool operator ==(Object other) {
     if (identical(this, other)) {
       return true;
     }
     if ((other is !String) ||
         (this.length != other.length)) {
       // TODO(5413632): Compare hash codes when both are present.
       return false;
     }
-    return this.compareTo(other) == 0;
+    final len = this.length;
+    for (int i = 0; i < len; i++) {
+      if (this.codeUnitAt(i) != other.codeUnitAt(i)) {
+        return false;
+      }
+    }
+    return true;
   }
 
+
   int compareTo(String other) {
     int thisLength = this.length;
     int otherLength = other.length;
     int len = (thisLength < otherLength) ? thisLength : otherLength;
     for (int i = 0; i < len; i++) {
       int thisCodePoint = this.codeUnitAt(i);
       int otherCodePoint = other.codeUnitAt(i);
       if (thisCodePoint < otherCodePoint) {
         return -1;
       }
@@ skipping 411 matching lines @@
     throw new UnsupportedError(
         "_OneByteString can only be allocated by the VM");
   }
 
   int get hashCode native "String_getHashCode";
 
   bool _isWhitespace(int codePoint) {
     return _StringBase._isOneByteWhitespace(codePoint);
   }
 
+  bool operator ==(Object other) {
+    return super == other;
+  }
+
   String _substringUncheckedNative(int startIndex, int endIndex)
       native "OneByteString_substringUnchecked";
 
   List<String> _splitWithCharCode(int charCode)
       native "OneByteString_splitWithCharCode";
 
   List<String> split(Pattern pattern) {
     if ((pattern._cid == _OneByteString._classId) && (pattern.length == 1)) {
       return _splitWithCharCode(pattern.codeUnitAt(0));
     }
@@ skipping 32 matching lines @@
 
 class _TwoByteString extends _StringBase implements String {
   factory _TwoByteString._uninstantiable() {
     throw new UnsupportedError(
         "_TwoByteString can only be allocated by the VM");
   }
 
   bool _isWhitespace(int codePoint) {
     return _StringBase._isTwoByteWhitespace(codePoint);
   }
+
+  bool operator ==(Object other) {
+    return super == other;
+  }
 }
 
 
 class _ExternalOneByteString extends _StringBase implements String {
   factory _ExternalOneByteString._uninstantiable() {
     throw new UnsupportedError(
         "_ExternalOneByteString can only be allocated by the VM");
   }
 
   bool _isWhitespace(int codePoint) {
     return _StringBase._isOneByteWhitespace(codePoint);
   }
+
+  bool operator ==(Object other) {
+    return super == other;
+  }
 }
 
 
 class _ExternalTwoByteString extends _StringBase implements String {
   factory _ExternalTwoByteString._uninstantiable() {
     throw new UnsupportedError(
         "_ExternalTwoByteString can only be allocated by the VM");
   }
 
   bool _isWhitespace(int codePoint) {
     return _StringBase._isTwoByteWhitespace(codePoint);
   }
+
+  bool operator ==(Object other) {
+    return super == other;
+  }
 }
 
 
 class _StringMatch implements Match {
   const _StringMatch(int this.start,
                      String this.input,
                      String this.pattern);
 
   int get end => start + pattern.length;
   String operator[](int g) => group(g);
@@ skipping 25 matching lines @@
 class _CodeUnits extends Object with ListMixin<int>,
                                      UnmodifiableListMixin<int> {
   /** The string that this is the code units of. */
   String _string;
 
   _CodeUnits(this._string);
 
   int get length => _string.length;
   int operator[](int i) => _string.codeUnitAt(i);
 }