Reject high- and low-surrogates in escaped code points.

runtime/vm/scanner.cc

 // 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.
 
 #include "vm/scanner.h"
 
 #include "platform/assert.h"
 #include "vm/flags.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
@@ skipping 455 matching lines @@
       break;
     }
     *value <<= 4;
     *value |= Utils::HexDigitToInt(c0_);
     ReadChar();
   }
   return true;
 }
 
 
-bool Scanner::ScanEscapedCodePoint(uint32_t* code_point) {
+void Scanner::ScanEscapedCodePoint(uint32_t* code_point) {
   ASSERT(c0_ == 'u' || c0_ == 'x');
   bool is_valid;
   if (c0_ == 'x') {
     is_valid = ScanHexDigits(2, code_point);
   } else if (c0_ == 'u' && LookaheadChar(1) != '{') {
     is_valid = ScanHexDigits(4, code_point);
   } else {
     ReadChar();  // Skip left curly bracket.
     is_valid = ScanHexDigits(1, 6, code_point);
     if (is_valid) {
       if (c0_ != '}') {
         ErrorMsg("expected '}' after character code");
-        return false;
-      }
-      if (*code_point > 0x10FFFF) {
-        ErrorMsg("invalid code point");
-        return false;
+        return;
       }
     }
   }
-  return is_valid;
+  if (is_valid &&
+      ((*code_point > 0x10FFFF) ||
+       ((*code_point & 0xFFFFF800) == 0xD800))) {
+    ErrorMsg("invalid code point");
+  }
 }
 
 
 void Scanner::ScanLiteralStringChars(bool is_raw) {
   GrowableArray<uint32_t> string_chars(64);
 
   ASSERT(IsScanningString());
   // We are at the first character of a string literal piece. A string literal
   // can be broken up into multiple pieces by string interpolation.
   while (true) {
@@ skipping 19 matching lines @@
         case 't':
           escape_char = '\t';
           break;
         case 'b':
           escape_char = '\b';
           break;
         case 'v':
           escape_char = '\v';
           break;
         case 'u':
-        case 'x':
-          if (!ScanEscapedCodePoint(&escape_char)) {
-            EndStringLiteral();
-            return;
-          }
+        case 'x': {
+          ScanEscapedCodePoint(&escape_char);
           break;
+        }
         default:
           if ((c0_ == '\0') || ((c0_ == '\n') && !string_is_multiline_)) {
             ErrorMsg("unterminated string literal");
             EndStringLiteral();
             return;
           }
           escape_char = c0_;
           break;
       }
       string_chars.Add(escape_char);
     } else if (c0_ == '$' && !is_raw) {
       // Scanned a string piece.
       ASSERT(string_chars.data() != NULL);
       // Strings are canonicalized: Allocate a symbol.
       current_token_.literal = &String::ZoneHandle(
           String::NewSymbol(string_chars.data(), string_chars.length()));
-      current_token_.kind = Token::kSTRING;
+      // Preserve error tokens.
+      if (current_token_.kind != Token::kERROR) {
+        current_token_.kind = Token::kSTRING;
+      }
       return;
     } else if (c0_ == string_delimiter_) {
       // Check if we are at the end of the string literal.
       if (!string_is_multiline_ ||
           ((LookaheadChar(1) == string_delimiter_) &&
            (LookaheadChar(2) == string_delimiter_))) {
         if (string_is_multiline_) {
           ReadChar();  // Skip two string delimiters.
           ReadChar();
         }
-        Recognize(Token::kSTRING);
-        ASSERT(string_chars.data() != NULL);
-        // Strings are canonicalized: Allocate a symbol.
-        current_token_.literal = &String::ZoneHandle(
-            String::NewSymbol(string_chars.data(), string_chars.length()));
+        // Preserve error tokens.
+        if (current_token_.kind == Token::kERROR) {
+          ReadChar();
+        } else {
+          Recognize(Token::kSTRING);
+          ASSERT(string_chars.data() != NULL);
+          // Strings are canonicalized: Allocate a symbol.
+          current_token_.literal = &String::ZoneHandle(
+              String::NewSymbol(string_chars.data(), string_chars.length()));
+        }
         EndStringLiteral();
         return;
       } else {
         string_chars.Add(string_delimiter_);
       }
     } else {
       string_chars.Add(c0_);
     }
     ReadChar();
   }
@@ skipping 329 matching lines @@
               "%c%"PRIxPTR, kPrivateKeySeparator, key_value);
   const String& result = String::Handle(String::New(private_key));
   return result.raw();
 }
 
 
 void Scanner::InitOnce() {
 }
 
 }  // namespace dart