Harden a few builtins

src/uri.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
@@ skipping 65 matching lines @@
 function URIHexCharsToCharCode(highChar, lowChar) {
   var highCode = HexValueOf(highChar);
   var lowCode = HexValueOf(lowChar);
   if (highCode == -1 || lowCode == -1) {
     throw new $URIError("URI malformed");
   }
   return (highCode << 4) | lowCode;
 }
 
 
-function URIDecodeOctets(octets, result, index) {
-  if (!IS_STRING(result)) throw new $URIError("Internal error");
+// Users of this macro must ensure that OCTETS is an array and RESULT is a
+// sufficiently long two-byte sequential string.
+// INDEX will be modified as characters are added to RESULT.
+macro URI_DECODE_OCTETS(OCTETS, RESULT, INDEX)

[rossberg, 2014/05/21 14:30:15]

Let's at least add a comment that explains why this was done, and a TODO with
the plan to replace it with a scalable solution.

   var value;
-  var o0 = octets[0];
+  var o0 = OCTETS[0];
   if (o0 < 0x80) {
     value = o0;
   } else if (o0 < 0xc2) {
     throw new $URIError("URI malformed");
   } else {
-    var o1 = octets[1];
+    var o1 = OCTETS[1];
     if (o0 < 0xe0) {
       var a = o0 & 0x1f;
       if ((o1 < 0x80) || (o1 > 0xbf)) {
         throw new $URIError("URI malformed");
       }
       var b = o1 & 0x3f;
       value = (a << 6) + b;
       if (value < 0x80 || value > 0x7ff) {
         throw new $URIError("URI malformed");
       }
     } else {
-      var o2 = octets[2];
+      var o2 = OCTETS[2];
       if (o0 < 0xf0) {
         var a = o0 & 0x0f;
         if ((o1 < 0x80) || (o1 > 0xbf)) {
           throw new $URIError("URI malformed");
         }
         var b = o1 & 0x3f;
         if ((o2 < 0x80) || (o2 > 0xbf)) {
           throw new $URIError("URI malformed");
         }
         var c = o2 & 0x3f;
         value = (a << 12) + (b << 6) + c;
         if ((value < 0x800) || (value > 0xffff)) {
           throw new $URIError("URI malformed");
         }
       } else {
-        var o3 = octets[3];
+        var o3 = OCTETS[3];
         if (o0 < 0xf8) {
           var a = (o0 & 0x07);
           if ((o1 < 0x80) || (o1 > 0xbf)) {
             throw new $URIError("URI malformed");
           }
           var b = (o1 & 0x3f);
           if ((o2 < 0x80) || (o2 > 0xbf)) {
             throw new $URIError("URI malformed");
           }
           var c = (o2 & 0x3f);
           if ((o3 < 0x80) || (o3 > 0xbf)) {
             throw new $URIError("URI malformed");
           }
           var d = (o3 & 0x3f);
           value = (a << 18) + (b << 12) + (c << 6) + d;
           if ((value < 0x10000) || (value > 0x10ffff)) {
             throw new $URIError("URI malformed");
           }
         } else {
           throw new $URIError("URI malformed");
         }
       }
     }
   }
   if (0xD800 <= value && value <= 0xDFFF) {
     throw new $URIError("URI malformed");
   }
   if (value < 0x10000) {
-    if (index < 0 || index >= result.length) {
-      throw new $URIError("Internal error");
-    }
-    %_TwoByteSeqStringSetChar(result, index++, value);
-    return index;
+    %_TwoByteSeqStringSetChar(RESULT, INDEX++, value);
   } else {
-    if (index < 0 || index >= result.length - 1) {
-      throw new $URIError("Internal error");
-    }
-    %_TwoByteSeqStringSetChar(result, index++, (value >> 10) + 0xd7c0);
-    %_TwoByteSeqStringSetChar(result, index++, (value & 0x3ff) + 0xdc00);
-    return index;
+    %_TwoByteSeqStringSetChar(RESULT, INDEX++, (value >> 10) + 0xd7c0);
+    %_TwoByteSeqStringSetChar(RESULT, INDEX++, (value & 0x3ff) + 0xdc00);
   }
-}
+endmacro
 
 
 // ECMA-262, section 15.1.3
 function Encode(uri, unescape) {
   var uriLength = uri.length;
   var array = new InternalArray(uriLength);
   var index = 0;
   for (var k = 0; k < uriLength; k++) {
     var cc1 = uri.charCodeAt(k);
     if (unescape(cc1)) {
@@ skipping 65 matching lines @@
         while (((cc << ++n) & 0x80) != 0) { }
         if (n == 1 || n > 4) throw new $URIError("URI malformed");
         var octets = new $Array(n);
         octets[0] = cc;
         if (k + 3 * (n - 1) >= uriLength) throw new $URIError("URI malformed");
         for (var i = 1; i < n; i++) {
           if (uri.charAt(++k) != '%') throw new $URIError("URI malformed");
           octets[i] = URIHexCharsToCharCode(uri.charCodeAt(++k),
                                             uri.charCodeAt(++k));
         }
-        index = URIDecodeOctets(octets, two_byte, index);
+        URI_DECODE_OCTETS(octets, two_byte, index);
       } else  if (reserved(cc)) {
         %_TwoByteSeqStringSetChar(two_byte, index++, 37);  // '%'.
         %_TwoByteSeqStringSetChar(two_byte, index++, uri.charCodeAt(k - 1));
         %_TwoByteSeqStringSetChar(two_byte, index++, uri.charCodeAt(k));
       } else {
         %_TwoByteSeqStringSetChar(two_byte, index++, cc);
       }
     } else {
       %_TwoByteSeqStringSetChar(two_byte, index++, code);
     }
@@ skipping 172 matching lines @@
     "escape", URIEscapeJS,
     "unescape", URIUnescapeJS,
     "decodeURI", URIDecode,
     "decodeURIComponent", URIDecodeComponent,
     "encodeURI", URIEncode,
     "encodeURIComponent", URIEncodeComponent
   ));
 }
 
 SetUpUri();