Fixing up backslash detection in json escaping and adding more tests.

Author: stgates

Release/src/json/json.cpp

@@ -340,8 +340,8 @@ bool web::json::number::is_int64() const
 
 bool web::json::details::_String::has_escape_chars(const _String &str)
 {
-    static const std::array<::utility::string_t::value_type, 33> escapes =
-        { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, /* 0x00 - 0x1F */ '\"' };
+    static const std::array<::utility::string_t::value_type, 34> escapes =
+        { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, /* 0x00 - 0x1F */ '\"', '\\' };
 
     // Provide the range otherwise find_first_of will think the first null terminator character is the end.
     return str.m_string.find_first_of(escapes.data(), 0, escapes.size()) != utility::string_t::npos;

Release/tests/functional/json/parsing_tests.cpp

@@ -225,7 +225,15 @@ TEST(escaped_unicode_string)
 
 TEST(escaping_control_characters)
 {
+    std::vector<int> chars;
     for (int i = 0; i <= 0x1F; ++i)
+    {
+        chars.push_back(i);
+    }
+    chars.push_back(0x5C); // backslash '\'
+    chars.push_back(0x22); // quotation '"'
+
+    for (int i : chars)
     {
         ::utility::stringstream_t ss;
         ss << U("\"\\u") << std::uppercase << std::setfill(U('0')) << std::setw(4) << std::hex << i << U("\"");
@@ -251,6 +259,14 @@ TEST(escaping_control_characters)
         {
             expectedStr = U("\"\\r\"");
         }
+        else if (i == 0x5C)
+        {
+            expectedStr = U("\"\\\\\"");
+        }
+        else if (i == 0x22)
+        {
+            expectedStr = U("\"\\\"\"");
+        }
 
         // Try constructing a json string value directly.
         ::utility::string_t schar;