Allow escaped apostrophe in values (#1639)

* Allow escaped apostrophe in values

* Allow escaped apostrophe in values

* Canonical flag name

* Add translation for escaped apostrophe

Co-authored-by: Milo Yip <miloyip@gmail.com>

doc/dom.md

@@ -119,6 +119,7 @@ Parse flags                   | Meaning
 `kParseNumbersAsStringsFlag`  | Parse numerical type values as strings.
 `kParseTrailingCommasFlag`    | Allow trailing commas at the end of objects and arrays (relaxed JSON syntax).
 `kParseNanAndInfFlag`         | Allow parsing `NaN`, `Inf`, `Infinity`, `-Inf` and `-Infinity` as `double` values (relaxed JSON syntax).
+`kParseEscapedApostropheFlag` | Allow escaped apostrophe `\'` in strings (relaxed JSON syntax).
 
 By using a non-type template parameter, instead of a function parameter, C++ compiler can generate code which is optimized for specified combinations, improving speed, and reducing code size (if only using a single specialization). The downside is the flags needed to be determined in compile-time.
 

doc/dom.zh-cn.md

@@ -119,6 +119,7 @@ GenericDocument& GenericDocument::Parse(const Ch* str);
 `kParseNumbersAsStringsFlag`  | 把数字类型解析成字符串。
 `kParseTrailingCommasFlag`    | 容许在对象和数组结束前含有逗号（放宽的 JSON 语法）。
 `kParseNanAndInfFlag`         | 容许 `NaN`、`Inf`、`Infinity`、`-Inf` 及 `-Infinity` 作为 `double` 值（放宽的 JSON 语法）。
+`kParseEscapedApostropheFlag` | 容许字符串中转义单引号 `\'` （放宽的 JSON 语法）。
 
 由于使用了非类型模板参数，而不是函数参数，C++ 编译器能为个别组合生成代码，以改善性能及减少代码尺寸（当只用单种特化）。缺点是需要在编译期决定标志。
 

include/rapidjson/reader.h

@@ -154,6 +154,7 @@ enum ParseFlag {
     kParseNumbersAsStringsFlag = 64,    //!< Parse all numbers (ints/doubles) as strings.
     kParseTrailingCommasFlag = 128, //!< Allow trailing commas at the end of objects and arrays.
     kParseNanAndInfFlag = 256,      //!< Allow parsing NaN, Inf, Infinity, -Inf and -Infinity as doubles.
+    kParseEscapedApostropheFlag = 512,  //!< Allow escaped apostrophe in strings.
     kParseDefaultFlags = RAPIDJSON_PARSE_DEFAULT_FLAGS  //!< Default parse flags. Can be customized by defining RAPIDJSON_PARSE_DEFAULT_FLAGS
 };
 
@@ -1014,6 +1015,10 @@ private:
                     is.Take();
                     os.Put(static_cast<typename TEncoding::Ch>(escape[static_cast<unsigned char>(e)]));
                 }
+                else if ((parseFlags & kParseEscapedApostropheFlag) && RAPIDJSON_LIKELY(e == '\'')) { // Allow escaped apostrophe
+                    is.Take();
+                    os.Put('\'');
+                }
                 else if (RAPIDJSON_LIKELY(e == 'u')) {    // Unicode
                     is.Take();
                     unsigned codepoint = ParseHex4(is, escapeOffset);

test/unittest/readertest.cpp

@@ -2198,4 +2198,28 @@ TEST(Reader, ParseNanAndInfinity) {
 #undef TEST_NAN_INF
 }
 
+TEST(Reader, EscapedApostrophe) {
+    const char json[] = " { \"foo\": \"bar\\'buzz\" } ";
+
+    BaseReaderHandler<> h;
+
+    {
+        StringStream s(json);
+        Reader reader;
+        ParseResult r = reader.Parse<kParseNoFlags>(s, h);
+        EXPECT_TRUE(reader.HasParseError());
+        EXPECT_EQ(kParseErrorStringEscapeInvalid, r.Code());
+        EXPECT_EQ(14u, r.Offset());
+    }
+
+    {
+        StringStream s(json);
+        Reader reader;
+        ParseResult r = reader.Parse<kParseEscapedApostropheFlag>(s, h);
+        EXPECT_FALSE(reader.HasParseError());
+        EXPECT_EQ(kParseErrorNone, r.Code());
+        EXPECT_EQ(0u, r.Offset());
+    }
+}
+
 RAPIDJSON_DIAG_POP