Short-circuit Uri._uriEncode for components that don't need encoding.

sdk/lib/core/uri.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.
 
 part of dart.core;
 
 /**
  * A parsed URI, such as a URL.
  *
  * **See also:**
@@ skipping 2242 matching lines @@
 
   /**
    * This is the internal implementation of JavaScript's encodeURI function.
    * It encodes all characters in the string [text] except for those
    * that appear in [canonicalTable], and returns the escaped string.
    */
   static String _uriEncode(List<int> canonicalTable,
                            String text,
                            {Encoding encoding: UTF8,
                             bool spaceToPlus: false}) {
+    if (_noUriEncodingNeeded(canonicalTable, text, encoding)) return text;
+
     byteToHex(byte, buffer) {
       const String hex = '0123456789ABCDEF';
       buffer.writeCharCode(hex.codeUnitAt(byte >> 4));
       buffer.writeCharCode(hex.codeUnitAt(byte & 0x0f));
     }
 
     // Encode the string into bytes then generate an ASCII only string
     // by percent encoding selected bytes.
     StringBuffer result = new StringBuffer();
     var bytes = encoding.encode(text);
     for (int i = 0; i < bytes.length; i++) {
       int byte = bytes[i];
       if (byte < 128 &&
           ((canonicalTable[byte >> 4] & (1 << (byte & 0x0f))) != 0)) {
         result.writeCharCode(byte);
       } else if (spaceToPlus && byte == _SPACE) {
         result.writeCharCode(_PLUS);
       } else {
         result.writeCharCode(_PERCENT);
         byteToHex(byte, result);
       }
     }
     return result.toString();
   }
 
+  static bool _noUriEncodingNeeded(
+      List<int> canonicalTable, String text, Encoding encoding) {
+    if (encoding != UTF8) return false;
+    for (int i = 0; i < text.length; i++) {
+      int code = text.codeUnitAt(i);
+      if (code >= 128) return false;
+      if ((canonicalTable[code >> 4] & (1 << (code & 0x0f))) == 0) return false;
+    }
+    return true;
+  }
+
   /**
    * Convert a byte (2 character hex sequence) in string [s] starting
    * at position [pos] to its ordinal value
    */
   static int _hexCharPairToByte(String s, int pos) {
     int byte = 0;
     for (int i = 0; i < 2; i++) {
       var charCode = s.codeUnitAt(pos + i);
       if (0x30 <= charCode && charCode <= 0x39) {
         byte = byte * 16 + charCode - 0x30;
@@ skipping 306 matching lines @@
       0xafff,   // 0x30 - 0x3f  1111111111110101
                 //              @ABCDEFGHIJKLMNO
       0xffff,   // 0x40 - 0x4f  1111111111111111
                 //              PQRSTUVWXYZ    _
       0x87ff,   // 0x50 - 0x5f  1111111111100001
                 //               abcdefghijklmno
       0xfffe,   // 0x60 - 0x6f  0111111111111111
                 //              pqrstuvwxyz   ~
       0x47ff];  // 0x70 - 0x7f  1111111111100010
 }