Improve indexOf for one byte string receiver to work with other string classes.

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 118 matching lines @@
       }
     }
     return true;
   }
 
   bool endsWith(String other) {
     return _substringMatches(this.length - other.length, other);
   }
 
   bool startsWith(Pattern pattern, [int index = 0]) {
-    if (index < 0 || index > this.length) {
+    if ((index < 0) || (index > this.length)) {
       throw new RangeError.range(index, 0, this.length);
     }
     if (pattern is String) {
       return _substringMatches(index, pattern);
     }
     return pattern.matchAsPrefix(this, index) != null;
   }
 
   int indexOf(Pattern pattern, [int start = 0]) {
-    if (start < 0 || start > this.length) {
+    if ((start < 0) || (start > this.length)) {
       throw new RangeError.range(start, 0, this.length);
     }
     if (pattern is String) {
       String other = pattern;
       int maxIndex = this.length - other.length;
       // TODO: Use an efficient string search (e.g. BMH).
       for (int index = start; index <= maxIndex; index++) {
         if (_substringMatches(index, other)) {
           return index;
         }
@@ skipping 409 matching lines @@
       _OneByteString e = strings[i];
       final eLength = e.length;
       for (int s = 0; s < eLength; s++) {
         res._setAt(rIx++, e.codeUnitAt(s));
       }
     }
     return res;
   }
 
   int indexOf(Pattern pattern, [int start = 0]) {
-    final len = this.length;
     // Specialize for single character pattern.
-    // TODO(srdjan): Implement for other string classes.
-    if ((pattern._cid == _OneByteString._classId) &&
-        (pattern.length == 1) &&
-        (start >= 0) && (start < len)) {
-      final patternCu0 = pattern.codeUnitAt(0);
-      for (int i = start; i < len; i++) {
-        if (this.codeUnitAt(i) == patternCu0) {
-          return i;
+    final pCid = pattern._cid;
+    if ((pCid == _OneByteString._classId) ||
+        (pCid == _TwoByteString._classId) ||
+        (pCid == _ExternalOneByteString._classId)) {
+      final len = this.length;
+      if ((pattern.length == 1) && (start >= 0) && (start < len)) {
+        final patternCu0 = pattern.codeUnitAt(0);
+        if (patternCu0 > 0xFF) {
+          return -1;
         }
+        for (int i = start; i < len; i++) {
+          if (this.codeUnitAt(i) == patternCu0) {
+            return i;
+          }
+        }
+        return -1;
       }
-      return -1;
     }
     return super.indexOf(pattern, start);
   }
 
   // Allocates a string of given length, expecting its content to be
   // set using _setAt.
   static _OneByteString _allocate(int length) native "OneByteString_allocate";
 
   // This is internal helper method. Code point value must be a valid
   // Latin1 value (0..0xFF), index must be valid.
   void _setAt(int index, int codePoint) native "OneByteString_setAt";
 }
 
 
 class _TwoByteString extends _StringBase implements String {
+  static final int _classId = "\u{FFFF}"._cid;
+
   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 {
+  static final int _classId = _getCid();
+
   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;
   }
+
+  static int _getCid() native "ExternalOneByteString_getCid";
 }
 
 
 class _ExternalTwoByteString extends _StringBase implements String {
   factory _ExternalTwoByteString._uninstantiable() {
     throw new UnsupportedError(
         "_ExternalTwoByteString can only be allocated by the VM");
   }
 
   bool _isWhitespace(int codePoint) {
@@ skipping 41 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);
 }