porymap/include/lib/orderedjson.h

/* poryjson
 *
 * poryjson is a modified version of json11, which adds support to preserve the key order
 * when dumping json objects, and support to Qt classes
 *
 * json11 is a tiny JSON library for C++11, providing JSON parsing and serialization.
 *
 * The core object provided by the library is json11::Json. A Json object represents any JSON
 * value: null, bool, number (int or double), string (std::string), array (std::vector), or
 * object (std::map).
 *
 * Json objects act like values: they can be assigned, copied, moved, compared for equality or
 * order, etc. There are also helper methods Json::dump, to serialize a Json to a string, and
 * Json::parse (static) to parse a std::string as a Json object.
 *
 * Internally, the various types of Json object are represented by the JsonValue class
 * hierarchy.
 *
 * A note on numbers - JSON specifies the syntax of number formatting but not its semantics,
 * so some JSON implementations distinguish between integers and floating-point numbers, while
 * some don't. In json11, we choose the latter. Because some JSON implementations (namely
 * Javascript itself) treat all numbers as the same type, distinguishing the two leads
 * to JSON that will be *silently* changed by a round-trip through those implementations.
 * Dangerous! To avoid that risk, json11 stores all numbers as double internally, but also
 * provides integer helpers.
 *
 * Fortunately, double-precision IEEE754 ('double') can precisely store any integer in the
 * range +/-2^53, which includes every 'int' on most systems. (Timestamps often use int64
 * or long long to avoid the Y2038K problem; a double storing microseconds since some epoch
 * will be exact for +/- 275 years.)
 */

/* Copyright (c) 2013 Dropbox, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#pragma once
#ifndef ORDERED_JSON_H
#define ORDERED_JSON_H

#include <QString>
#include <QVector>
#include <QPair>
#include <QFile>
#include <QTextStream>

#include <memory>
#include <initializer_list>

#include <QtGlobal>
#include "orderedmap.h"

#ifdef _MSC_VER
#if _MSC_VER <= 1800 // VS 2013
#ifndef noexcept
#define noexcept throw()
#endif

#ifndef snprintf
#define snprintf _snprintf_s
#endif
#endif
#endif

namespace poryjson {

enum JsonParse { STANDARD, COMMENTS };

class JsonValue;

class Json final {
public:
    // Types
    enum Type { NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT };

    // Array and object typedefs
    typedef QVector<Json> array;
    typedef tsl::ordered_map<QString, Json> object;

    // Constructors for the various types of JSON value.
    Json() noexcept; // NUL
    Json(std::nullptr_t) noexcept; // NUL
    Json(double value); // NUMBER
    Json(int value); // NUMBER
    Json(bool value); // BOOL
    Json(const QString& value); // STRING
    Json(QString&& value); // STRING
    Json(const char* value); // STRING
    Json(const array& values); // ARRAY
    Json(array&& values); // ARRAY
    Json(const object& values); // OBJECT
    Json(object&& values); // OBJECT

    // Implicit constructor: anything with a to_json() function.
    template <class T, class = decltype(&T::to_json)> Json(const T& t) : Json(t.to_json()) {
    }

    // Implicit constructor: map-like objects (std::map, std::unordered_map, etc)
    template <class M, typename std::enable_if<std::is_constructible<QString, decltype(std::declval<M>().begin()->first)>::value
                               && std::is_constructible<Json, decltype(std::declval<M>().begin()->second)>::value,
                           int>::type
        = 0>
    Json(const M& m)
        : Json(object(m.begin(), m.end())) {
    }

    // Implicit constructor: vector-like objects (std::list, std::vector, std::set, etc)
    template <class V, typename std::enable_if<std::is_constructible<Json, decltype(*std::declval<V>().begin())>::value, int>::type = 0>
    Json(const V& v)
        : Json(array(v.begin(), v.end())) {
    }

    // This prevents Json(some_pointer) from accidentally producing a bool. Use
    // Json(bool(some_pointer)) if that behavior is desired.
    Json(void*) = delete;

    // Accessors
    Type type() const;

    bool is_null() const {
        return type() == NUL;
    }
    bool is_number() const {
        return type() == NUMBER;
    }
    bool is_bool() const {
        return type() == BOOL;
    }
    bool is_string() const {
        return type() == STRING;
    }
    bool is_array() const {
        return type() == ARRAY;
    }
    bool is_object() const {
        return type() == OBJECT;
    }

    // Return the enclosed value if this is a number, 0 otherwise. Note that poryjson does not
    // distinguish between integer and non-integer numbers - number_value() and int_value()
    // can both be applied to a NUMBER-typed object.
    double number_value() const;
    int int_value() const;

    // Return the enclosed value if this is a boolean, false otherwise.
    bool bool_value() const;
    // Return the enclosed string if this is a string, "" otherwise.
    const QString& string_value() const;
    // Return the enclosed std::vector if this is an array, or an empty vector otherwise.
    const array& array_items() const;
    // Return the enclosed std::map if this is an object, or an empty map otherwise.
    const object& object_items() const;

    // Return a reference to arr[i] if this is an array, Json() otherwise.
    const Json& operator[](int i) const;
    // Return a reference to obj[key] if this is an object, Json() otherwise.
    const Json& operator[](const QString& key) const;

    // Serialize.
    void dump(QString& out, int*) const;
    QString dump(int* indent = nullptr) const {
        QString out;
        if (!indent) {
            int temp = 0;
            indent = &temp;
        }
        dump(out, indent);
        return out;
    }

    // Parse. If parse fails, return Json() and assign an error message to err.
    static Json parse(const QString& in, QString& err, JsonParse strategy = JsonParse::STANDARD);
    static Json parse(const char* in, QString& err, JsonParse strategy = JsonParse::STANDARD) {
        if (in) {
            return parse(QString(in), err, strategy);
        } else {
            err = "null input";
            return nullptr;
        }
    }

    bool operator==(const Json& rhs) const;
    bool operator<(const Json& rhs) const;
    bool operator!=(const Json& rhs) const {
        return !(*this == rhs);
    }
    bool operator<=(const Json& rhs) const {
        return !(rhs < *this);
    }
    bool operator>(const Json& rhs) const {
        return (rhs < *this);
    }
    bool operator>=(const Json& rhs) const {
        return !(*this < rhs);
    }

private:
    std::shared_ptr<JsonValue> m_ptr;
};

class JsonDoc {
public:
    JsonDoc(Json* object) {
        this->m_obj = object;
        this->m_indent = 0;
    };

    void dump(QFile* file) {
        QTextStream fileStream(file);
        fileStream << m_obj->dump(&m_indent);
        fileStream << "\n"; // pad file with newline
    }

private:
    Json* m_obj;
    int m_indent;
};

// Internal class hierarchy - JsonValue objects are not exposed to users of this API.
class JsonValue {
protected:
    friend class Json;
    friend class JsonInt;
    friend class JsonDouble;
    virtual Json::Type type() const = 0;
    virtual bool equals(const JsonValue* other) const = 0;
    virtual bool less(const JsonValue* other) const = 0;
    virtual void dump(QString& out, int* indent) const = 0;
    virtual double number_value() const;
    virtual int int_value() const;
    virtual bool bool_value() const;
    virtual const QString& string_value() const;
    virtual const Json::array& array_items() const;
    virtual const Json& operator[](int i) const;
    virtual const Json::object& object_items() const;
    virtual const Json& operator[](const QString& key) const;
    virtual ~JsonValue() {
    }
};

} // namespace poryjson

#endif // ORDERED_JSON_H