Fix crashing bug due to the fact that external one byte strings cannot be escaped

runtime/vm/object_test.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/assembler.h"
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
@@ skipping 1511 matching lines @@
   EXPECT(concat.Equals("\xC3\xB6\xC3\xB1\xC3\xA9\xC3\xB6\xC3\xB1\xC3\xA9"));
 
   const String& substr = String::Handle(String::SubString(str, 1, 1));
   EXPECT(!substr.IsExternalOneByteString());
   EXPECT(substr.IsOneByteString());
   EXPECT_EQ(1, substr.Length());
   EXPECT(substr.Equals("\xC3\xB1"));
 }
 
 
+TEST_CASE(EscapeSpecialCharactersOneByteString) {
+  uint8_t characters[] =
+      { 'a', '\n', '\f', '\b', '\t', '\v', '\r', '\\', '$', 'z' };
+  intptr_t len = ARRAY_SIZE(characters);
+
+  const String& str =
+      String::Handle(
+          OneByteString::New(characters, len, Heap::kNew));
+  EXPECT(str.IsOneByteString());
+  EXPECT_EQ(str.Length(), len);
+  EXPECT(str.Equals("a\n\f\b\t\v\r\\$z"));
+  const String& escaped_str =
+      String::Handle(String::EscapeSpecialCharacters(str));
+  EXPECT(escaped_str.Equals("a\\n\\f\\b\\t\\v\\r\\\\\\$z"));
+}
+
+
+TEST_CASE(EscapeSpecialCharactersExternalOneByteString) {
+  uint8_t characters[] =
+      { 'a', '\n', '\f', '\b', '\t', '\v', '\r', '\\', '$', 'z' };
+  intptr_t len = ARRAY_SIZE(characters);
+
+  const String& str =
+      String::Handle(
+          ExternalOneByteString::New(characters, len, NULL, NULL, Heap::kNew));
+  EXPECT(!str.IsOneByteString());
+  EXPECT(str.IsExternalOneByteString());
+  EXPECT_EQ(str.Length(), len);
+  EXPECT(str.Equals("a\n\f\b\t\v\r\\$z"));
+  const String& escaped_str =
+      String::Handle(String::EscapeSpecialCharacters(str));
+  EXPECT(escaped_str.Equals("a\\n\\f\\b\\t\\v\\r\\\\\\$z"));
+}
+
+TEST_CASE(EscapeSpecialCharactersTwoByteString) {
+  uint16_t characters[] =
+      { 'a', '\n', '\f', '\b', '\t', '\v', '\r', '\\', '$', 'z' };
+  intptr_t len = ARRAY_SIZE(characters);
+
+  const String& str =
+      String::Handle(TwoByteString::New(characters, len, Heap::kNew));
+  EXPECT(str.IsTwoByteString());
+  EXPECT_EQ(str.Length(), len);
+  EXPECT(str.Equals("a\n\f\b\t\v\r\\$z"));
+  const String& escaped_str =
+      String::Handle(String::EscapeSpecialCharacters(str));
+  EXPECT(escaped_str.Equals("a\\n\\f\\b\\t\\v\\r\\\\\\$z"));
+}
+
+
+TEST_CASE(EscapeSpecialCharactersExternalTwoByteString) {
+  uint16_t characters[] =
+      { 'a', '\n', '\f', '\b', '\t', '\v', '\r', '\\', '$', 'z' };
+  intptr_t len = ARRAY_SIZE(characters);
+
+  const String& str =
+      String::Handle(
+          ExternalTwoByteString::New(characters, len, NULL, NULL, Heap::kNew));
+  EXPECT(str.IsExternalTwoByteString());
+  EXPECT_EQ(str.Length(), len);
+  EXPECT(str.Equals("a\n\f\b\t\v\r\\$z"));
+  const String& escaped_str =
+      String::Handle(String::EscapeSpecialCharacters(str));
+  EXPECT(escaped_str.Equals("a\\n\\f\\b\\t\\v\\r\\\\\\$z"));
+}
+
+
 TEST_CASE(ExternalTwoByteString) {
   uint16_t characters[] = { 0x1E6B, 0x1E85, 0x1E53 };
   intptr_t len = ARRAY_SIZE(characters);
 
   const String& str =
       String::Handle(
           ExternalTwoByteString::New(characters, len, NULL, NULL, Heap::kNew));
   EXPECT(!str.IsTwoByteString());
   EXPECT(str.IsExternalTwoByteString());
   EXPECT_EQ(str.Length(), len);
@@ skipping 1934 matching lines @@
   cls = Object::dynamic_class();
   array = cls.fields();
   EXPECT(!array.IsNull());
   EXPECT(array.IsArray());
   array = cls.functions();
   EXPECT(!array.IsNull());
   EXPECT(array.IsArray());
 }
 
 }  // namespace dart