10.9

1 files changed, 541 insertions, 0 deletions

diff --git a/zen/json.h b/zen/json.h
new file mode 100644
index 00000000..374a3f14
--- /dev/null
+++ b/zen/json.h
@@ -0,0 +1,541 @@
+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#ifndef JSON_H_0187348321748321758934215734
+#define JSON_H_0187348321748321758934215734
+
+#include <zen/string_tools.h>
+
+
+namespace zen
+{
+//https://tools.ietf.org/html/rfc8259
+struct JsonValue
+{
+    enum class Type
+    {
+        null,    //
+        boolean, //primitive types
+        number,  //
+        string,  //
+        object,
+        array,
+    };
+
+    explicit JsonValue() {}
+    explicit JsonValue(Type t) : type(t) {}
+    explicit JsonValue(bool b)                 : type(Type::boolean), primVal(b ? "true" : "false") {}
+    explicit JsonValue(int64_t num)            : type(Type::number),  primVal(numberTo<std::string>(num)) {}
+    explicit JsonValue(double num)             : type(Type::number),  primVal(numberTo<std::string>(num)) {}
+    explicit JsonValue(const std::string& str) : type(Type::string),  primVal(str) {}
+
+    Type type = Type::null;
+    std::string                                       primVal; //for primitive types
+    std::map<std::string, std::unique_ptr<JsonValue>> objectVal; //"[...] most implementations of JSON libraries do not accept duplicate keys [...]" => fine!
+    std::vector<std::unique_ptr<JsonValue>>           arrayVal;
+};
+
+
+std::string serializeJson(const JsonValue& jval,
+                          const std::string& lineBreak = "\r\n",
+                          const std::string& indent    = "    "); //noexcept
+
+
+struct JsonParsingError
+{
+    JsonParsingError(size_t rowNo, size_t colNo) : row(rowNo), col(colNo) {}
+    const size_t row; //beginning with 0
+    const size_t col; //
+};
+JsonValue parseJson(const std::string& stream); //throw JsonParsingError
+
+
+
+//helper functions for JsonValue access:
+inline
+const JsonValue* getChildFromJsonObject(const JsonValue& jvalue, const std::string& name)
+{
+    if (jvalue.type != JsonValue::Type::object)
+        return nullptr;
+
+    auto it = jvalue.objectVal.find(name);
+    if (it == jvalue.objectVal.end())
+        return nullptr;
+
+    return it->second.get();
+}
+
+
+inline
+std::optional<std::string> getPrimitiveFromJsonObject(const JsonValue& jvalue, const std::string& name)
+{
+    if (const JsonValue* childValue = getChildFromJsonObject(jvalue, name))
+        if (childValue->type != JsonValue::Type::object &&
+            childValue->type != JsonValue::Type::array)
+            return childValue->primVal;
+    return std::nullopt;
+}
+
+
+
+
+
+//---------------------- implementation ----------------------
+namespace json_impl
+{
+namespace
+{
+std::string jsonEscape(const std::string& str)
+{
+    std::string output;
+    for (const char c : str)
+    {
+        if      (c == '"')  output += "\\\""; //escaping mandatory
+        else if (c == '\\') output += "\\\\"; //
+
+        else if (c == '\b') output += "\\b"; //
+        else if (c == '\f') output += "\\f"; //
+        else if (c == '\n') output += "\\n"; //prefer compact escaping
+        else if (c == '\r') output += "\\r"; //
+        else if (c == '\t') output += "\\t"; //
+
+        else if (static_cast<unsigned char>(c) < 32)
+        {
+            const auto hexDigits = hexify(c);
+            output += "\\u00";
+            output += hexDigits.first;
+            output += hexDigits.second;
+        }
+        else
+            output += c;
+    }
+    return output;
+}
+
+
+std::string jsonUnescape(const std::string& str)
+{
+    std::string output;
+    std::basic_string<impl::Char16> utf16Buf;
+
+    auto flushUtf16 = [&]
+    {
+        if (!utf16Buf.empty())
+        {
+            impl::UtfDecoder<impl::Char16> decoder(utf16Buf.c_str(), utf16Buf.size());
+            while (std::optional<impl::CodePoint> cp = decoder.getNext())
+                impl::codePointToUtf<char>(*cp, [&](char c) { output += c; });
+            utf16Buf.clear();
+        }
+    };
+    auto writeOut = [&](char c)
+    {
+        flushUtf16();
+        output += c;
+    };
+
+    for (auto it = str.begin(); it != str.end(); ++it)
+    {
+        const char c = *it;
+
+        if (c == '\\')
+        {
+            ++it;
+            if (it == str.end()) //unexpected end!
+            {
+                writeOut(c);
+                break;
+            }
+
+            const char c2 = *it;
+            if (c2 == '"' ||
+                c2 == '\\' ||
+                c2 == '/')
+                writeOut(c2);
+            else if (c2 == 'b') writeOut('\b');
+            else if (c2 == 'f') writeOut('\f');
+            else if (c2 == 'n') writeOut('\n');
+            else if (c2 == 'r') writeOut('\r');
+            else if (c2 == 't') writeOut('\t');
+
+            else if (c2 == 'u' &&
+                     str.end() - it >= 5 &&
+                     isHexDigit(it[1])   &&
+                     isHexDigit(it[2])   &&
+                     isHexDigit(it[3])   &&
+                     isHexDigit(it[4]))
+            {
+                utf16Buf += static_cast<impl::Char16>(static_cast<unsigned char>(unhexify(it[1], it[2])) * 256 +
+                                                      static_cast<unsigned char>(unhexify(it[3], it[4])));
+                it += 4;
+            }
+            else //unknown escape sequence!
+            {
+                writeOut(c);
+                writeOut(c2);
+            }
+        }
+        else
+            writeOut(c);
+    }
+    flushUtf16();
+    return output;
+}
+
+
+void serialize(const JsonValue& jval, std::string& stream,
+               const std::string& lineBreak,
+               const std::string& indent,
+               size_t indentLevel)
+{
+    //unlike our XML serialization the caller is repsonsible for line breaks and indentation of *first* line
+    auto writeIndent = [&](size_t level)
+    {
+        for (size_t i = 0; i < level; ++i)
+            stream += indent;
+    };
+
+    switch (jval.type)
+    {
+        case JsonValue::Type::null:
+            stream += "null";
+            break;
+
+        case JsonValue::Type::boolean:
+        case JsonValue::Type::number:
+            stream += jval.primVal;
+            break;
+
+        case JsonValue::Type::string:
+            stream += '"' + jsonEscape(jval.primVal) + '"';
+            break;
+
+        case JsonValue::Type::object:
+            stream += '{';
+            if (!jval.objectVal.empty())
+            {
+                for (auto it = jval.objectVal.begin(); it != jval.objectVal.end(); ++it)
+                {
+                    const auto& [childName, childValue] = *it;
+
+                    if (it != jval.objectVal.begin())
+                        stream += ',';
+
+                    stream += lineBreak;
+                    writeIndent(indentLevel + 1);
+
+                    stream += '"' + jsonEscape(childName) + "\":";
+
+                    if ((childValue->type == JsonValue::Type::object && !childValue->objectVal.empty()) ||
+                        (childValue->type == JsonValue::Type::array  && !childValue->arrayVal .empty()))
+                    {
+                        stream += lineBreak;
+                        writeIndent(indentLevel + 1);
+                    }
+                    else if (!indent.empty())
+                        stream += ' ';
+
+                    serialize(*childValue, stream, lineBreak, indent, indentLevel + 1);
+                }
+                stream += lineBreak;
+                writeIndent(indentLevel);
+            }
+            stream += '}';
+            break;
+
+        case JsonValue::Type::array:
+            stream += '[';
+            if (!jval.arrayVal.empty())
+            {
+                for (auto it = jval.arrayVal.begin(); it != jval.arrayVal.end(); ++it)
+                {
+                    const auto& childValue = **it;
+
+                    if (it != jval.arrayVal.begin())
+                        stream += ',';
+
+                    stream += lineBreak;
+                    writeIndent(indentLevel + 1);
+
+                    serialize(childValue, stream, lineBreak, indent, indentLevel + 1);
+                }
+                stream += lineBreak;
+                writeIndent(indentLevel);
+            }
+            stream += ']';
+            break;
+    }
+}
+}
+}
+
+
+inline
+std::string serializeJson(const JsonValue& jval,
+                          const std::string& lineBreak,
+                          const std::string& indent) //noexcept
+{
+    std::string output;
+    json_impl::serialize(jval, output, lineBreak, indent, 0);
+    output += lineBreak;
+    return output;
+}
+
+
+namespace json_impl
+{
+struct Token
+{
+    enum class Type
+    {
+        eof,
+        curlyOpen,
+        curlyClose,
+        squareOpen,
+        squareClose,
+        colon,
+        comma,
+        string,  //
+        number,  //primitive types
+        boolean, //
+        null,    //
+    };
+
+    Token(Type t) : type(t) {}
+
+    Type type;
+    std::string primVal; //for primitive types
+};
+
+class Scanner
+{
+public:
+    Scanner(const std::string& stream) : stream_(stream), pos_(stream_.begin())
+    {
+        if (zen::startsWith(stream_, BYTE_ORDER_MARK_UTF8))
+            pos_ += strLength(BYTE_ORDER_MARK_UTF8);
+    }
+
+    Token getNextToken() //throw JsonParsingError
+    {
+        //skip whitespace
+        pos_ = std::find_if(pos_, stream_.end(), std::not_fn(isJsonWhiteSpace));
+
+        if (pos_ == stream_.end())
+            return Token::Type::eof;
+
+        if (*pos_ == '{') return ++pos_, Token::Type::curlyOpen;
+        if (*pos_ == '}') return ++pos_, Token::Type::curlyClose;
+        if (*pos_ == '[') return ++pos_, Token::Type::squareOpen;
+        if (*pos_ == ']') return ++pos_, Token::Type::squareClose;
+        if (*pos_ == ':') return ++pos_, Token::Type::colon;
+        if (*pos_ == ',') return ++pos_, Token::Type::comma;
+        if (startsWith("null")) return pos_ += 4, Token(Token::Type::null);
+
+        if (startsWith("true"))
+        {
+            pos_ += 4;
+            Token tk(Token::Type::boolean);
+            tk.primVal = "true";
+            return tk;
+        }
+        if (startsWith("false"))
+        {
+            pos_ += 5;
+            Token tk(Token::Type::boolean);
+            tk.primVal = "false";
+            return tk;
+        }
+
+        if (*pos_ == '"')
+        {
+            for (auto it = ++pos_; it != stream_.end(); ++it)
+                if (*it == '"')
+                {
+                    Token tk(Token::Type::string);
+                    tk.primVal = jsonUnescape({ pos_, it });
+                    pos_ = ++it;
+                    return tk;
+                }
+                else if (*it == '\\') //skip next char
+                    if (++it == stream_.end())
+                        break;
+
+            throw JsonParsingError(posRow(), posCol());
+        }
+
+        //expect a number:
+        const auto itNumEnd = std::find_if(pos_, stream_.end(), std::not_fn(isJsonNumDigit));
+        if (itNumEnd == pos_)
+            throw JsonParsingError(posRow(), posCol());
+
+        Token tk(Token::Type::number);
+        tk.primVal.assign(pos_, itNumEnd);
+        pos_ = itNumEnd;
+        return tk;
+    }
+
+    size_t posRow() const //current row beginning with 0
+    {
+        const size_t crSum = std::count(stream_.begin(), pos_, '\r'); //carriage returns
+        const size_t nlSum = std::count(stream_.begin(), pos_, '\n'); //new lines
+        assert(crSum == 0 || nlSum == 0 || crSum == nlSum);
+        return std::max(crSum, nlSum); //be compatible with Linux/Mac/Win
+    }
+
+    size_t posCol() const //current col beginning with 0
+    {
+        //seek beginning of line
+        for (auto it = pos_; it != stream_.begin(); )
+        {
+            --it;
+            if (*it == '\r' || *it == '\n')
+                return pos_ - it - 1;
+        }
+        return pos_ - stream_.begin();
+    }
+
+private:
+    Scanner           (const Scanner&) = delete;
+    Scanner& operator=(const Scanner&) = delete;
+
+    static bool isJsonWhiteSpace(char c) { return c == ' ' || c == '\t' || c == '\r' || c == '\n'; }
+    static bool isJsonNumDigit  (char c) { return ('0' <= c && c <= '9') || c == '-' || c == '+' || c == '.' || c == 'e'|| c == 'E'; }
+
+    bool startsWith(const std::string& prefix) const
+    {
+        return zen::startsWith(StringRef<const char>(pos_, stream_.end()), prefix);
+    }
+
+    const std::string stream_;
+    std::string::const_iterator pos_;
+};
+
+
+class JsonParser
+{
+public:
+    JsonParser(const std::string& stream) :
+        scn_(stream),
+        tk_(scn_.getNextToken()) {} //throw JsonParsingError
+
+    JsonValue parse() //throw JsonParsingError
+    {
+        JsonValue jval = parseValue(); //throw JsonParsingError
+        expectToken(Token::Type::eof); //
+        return jval;
+    }
+
+private:
+    JsonParser           (const JsonParser&) = delete;
+    JsonParser& operator=(const JsonParser&) = delete;
+
+    JsonValue parseValue() //throw JsonParsingError
+    {
+        if (token().type == Token::Type::curlyOpen)
+        {
+            nextToken(); //throw JsonParsingError
+
+            JsonValue jval(JsonValue::Type::object);
+
+            if (token().type != Token::Type::curlyClose)
+                for (;;)
+                {
+                    expectToken(Token::Type::string); //throw JsonParsingError
+                    std::string name = token().primVal;
+                    nextToken(); //throw JsonParsingError
+
+                    consumeToken(Token::Type::colon); //throw JsonParsingError
+
+                    JsonValue value = parseValue(); //throw JsonParsingError
+                    jval.objectVal.emplace(std::move(name), std::make_unique<JsonValue>(std::move(value)));
+
+                    if (token().type != Token::Type::comma)
+                        break;
+                    nextToken(); //throw JsonParsingError
+                }
+
+            consumeToken(Token::Type::curlyClose); //throw JsonParsingError
+            return jval;
+        }
+        else if (token().type == Token::Type::squareOpen)
+        {
+            nextToken(); //throw JsonParsingError
+
+            JsonValue jval(JsonValue::Type::array);
+
+            if (token().type != Token::Type::squareClose)
+                for (;;)
+                {
+                    JsonValue value = parseValue();  //throw JsonParsingError
+                    jval.arrayVal.emplace_back(std::make_unique<JsonValue>(std::move(value)));
+
+                    if (token().type != Token::Type::comma)
+                        break;
+                    nextToken(); //throw JsonParsingError
+                }
+
+            consumeToken(Token::Type::squareClose); //throw JsonParsingError
+            return jval;
+        }
+        else if (token().type == Token::Type::string)
+        {
+            JsonValue jval(token().primVal);
+            nextToken(); //throw JsonParsingError
+            return jval;
+        }
+        else if (token().type == Token::Type::number)
+        {
+            JsonValue jval(JsonValue::Type::number);
+            jval.primVal = token().primVal;
+            nextToken(); //throw JsonParsingError
+            return jval;
+        }
+        else if (token().type == Token::Type::boolean)
+        {
+            JsonValue jval(JsonValue::Type::boolean);
+            jval.primVal = token().primVal;
+            nextToken(); //throw JsonParsingError
+            return jval;
+        }
+        else if (token().type == Token::Type::null)
+        {
+            nextToken(); //throw JsonParsingError
+            return JsonValue();
+        }
+        else //unexpected token
+            throw JsonParsingError(scn_.posRow(), scn_.posCol());
+    }
+
+    const Token& token() const { return tk_; }
+
+    void nextToken() { tk_ = scn_.getNextToken(); } //throw JsonParsingError
+
+    void expectToken(Token::Type t) //throw JsonParsingError
+    {
+        if (token().type != t)
+            throw JsonParsingError(scn_.posRow(), scn_.posCol());
+    }
+
+    void consumeToken(Token::Type t) //throw JsonParsingError
+    {
+        expectToken(t); //throw JsonParsingError
+        nextToken();    //
+    }
+
+    Scanner scn_;
+    Token tk_;
+};
+}
+
+inline
+JsonValue parseJson(const std::string& stream) //throw JsonParsingError
+{
+    return json_impl::JsonParser(stream).parse(); //throw JsonParsingError
+}
+}
+
+#endif //JSON_H_0187348321748321758934215734