Improve JSONReader performance by up to 55% by using std::string instead of wstring.

base/json/json_reader_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/json/json_reader.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/string_piece.h"
 #include "base/utf_string_conversions.h"
@@ skipping 439 matching lines @@
   EXPECT_EQ(L"\x7f51\x9875", UTF8ToWide(str_val));
 
   // Test invalid utf8 encoded input
   root.reset(JSONReader().JsonToValue("\"345\xb0\xa1\xb0\xa2\"",
                                       false, false));
   EXPECT_FALSE(root.get());
   root.reset(JSONReader().JsonToValue("\"123\xc0\x81\"",
                                       false, false));
   EXPECT_FALSE(root.get());
 
+  // Test utf16 encoded strings.
+  root.reset(JSONReader().JsonToValue("\"\\u20ac3,14\"", false, false));
+  ASSERT_TRUE(root.get());
+  EXPECT_TRUE(root->IsType(Value::TYPE_STRING));
+  str_val.clear();
+  EXPECT_TRUE(root->GetAsString(&str_val));
+  EXPECT_EQ("\xe2\x82\xac""3,14", str_val);
+
+  root.reset(JSONReader().JsonToValue("\"\\ud83d\\udca9\\ud83d\\udc6c\"",
+                                      false, false));
+  ASSERT_TRUE(root.get());
+  EXPECT_TRUE(root->IsType(Value::TYPE_STRING));
+  str_val.clear();
+  EXPECT_TRUE(root->GetAsString(&str_val));
+  EXPECT_EQ("\xf0\x9f\x92\xa9\xf0\x9f\x91\xac", str_val);
+
+  // Test invalid utf16 strings.
+  const char* cases[] = {
+    "\"\\u123\"",  // Invalid scalar.
+    "\"\\ud83d\"",  // Invalid scalar.
+    "\"\\u$%@!\"",  // Invalid scalar.
+    "\"\\uzz89\"",  // Invalid scalar.
+    "\"\\ud83d\\udca\"",  // Invalid lower surrogate.
+    "\"\\ud83d\\ud83d\"",  // Invalid lower surrogate.
+    "\"\\ud83foo\"",  // No lower surrogate.
+    "\"\\ud83\\foo\""  // No lower surrogate.
+  };
+  for (size_t i = 0; i < arraysize(cases); ++i) {
+    root.reset(JSONReader().JsonToValue(cases[i], false, false));
+    EXPECT_FALSE(root.get()) << cases[i];
+  }
+
   // Test invalid root objects.
   root.reset(JSONReader::Read("null", false));
   EXPECT_FALSE(root.get());
   root.reset(JSONReader::Read("true", false));
   EXPECT_FALSE(root.get());
   root.reset(JSONReader::Read("10", false));
   EXPECT_FALSE(root.get());
   root.reset(JSONReader::Read("\"root\"", false));
   EXPECT_FALSE(root.get());
 }
@@ skipping 88 matching lines @@
 
   root.reset(JSONReader::ReadAndReturnError("[\"xxx\\q\"]", false,
                                             &error_code, &error_message));
   EXPECT_FALSE(root.get());
   EXPECT_EQ(JSONReader::FormatErrorMessage(1, 7, JSONReader::kInvalidEscape),
             error_message);
   EXPECT_EQ(JSONReader::JSON_INVALID_ESCAPE, error_code);
 }
 
 }  // namespace base