sneedmc/launcher/Json.h

// Licensed under the Apache-2.0 license. See README.md for details.

#pragma once

#include <QJsonDocument>
#include <QJsonArray>
#include <QJsonObject>
#include <QDateTime>
#include <QUrl>
#include <QDir>
#include <QUuid>
#include <QVariant>
#include <memory>

#include "Exception.h"

namespace Json
{
class JsonException : public ::Exception
{
public:
    JsonException(const QString &message) : Exception(message) {}
};

/// @throw FileSystemException
void write(const QJsonDocument &doc, const QString &filename);
/// @throw FileSystemException
void write(const QJsonObject &object, const QString &filename);
/// @throw FileSystemException
void write(const QJsonArray &array, const QString &filename);

QByteArray toText(const QJsonObject &obj);
QByteArray toText(const QJsonArray &array);

/// @throw JsonException
QJsonDocument requireDocument(const QByteArray &data, const QString &what = "Document");
/// @throw JsonException
QJsonDocument requireDocument(const QString &filename, const QString &what = "Document");
/// @throw JsonException
QJsonObject requireObject(const QJsonDocument &doc, const QString &what = "Document");
/// @throw JsonException
QJsonArray requireArray(const QJsonDocument &doc, const QString &what = "Document");

/////////////////// WRITING ////////////////////

void writeString(QJsonObject & to, const QString &key, const QString &value);
void writeStringList(QJsonObject & to, const QString &key, const QStringList &values);

template<typename T>
QJsonValue toJson(const T &t)
{
    return QJsonValue(t);
}
template<>
QJsonValue toJson<QUrl>(const QUrl &url);
template<>
QJsonValue toJson<QByteArray>(const QByteArray &data);
template<>
QJsonValue toJson<QDateTime>(const QDateTime &datetime);
template<>
QJsonValue toJson<QDir>(const QDir &dir);
template<>
QJsonValue toJson<QUuid>(const QUuid &uuid);
template<>
QJsonValue toJson<QVariant>(const QVariant &variant);

template<typename T>
QJsonArray toJsonArray(const QList<T> &container)
{
    QJsonArray array;
    for (const T item : container)
    {
        array.append(toJson<T>(item));
    }
    return array;
}

////////////////// READING ////////////////////

/// @throw JsonException
template <typename T>
T requireIsType(const QJsonValue &value, const QString &what = "Value");

/// @throw JsonException
template<> double requireIsType<double>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> bool requireIsType<bool>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> int requireIsType<int>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QJsonObject requireIsType<QJsonObject>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QJsonArray requireIsType<QJsonArray>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QJsonValue requireIsType<QJsonValue>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QByteArray requireIsType<QByteArray>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QDateTime requireIsType<QDateTime>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QVariant requireIsType<QVariant>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QString requireIsType<QString>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QUuid requireIsType<QUuid>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QDir requireIsType<QDir>(const QJsonValue &value, const QString &what);
/// @throw JsonException
template<> QUrl requireIsType<QUrl>(const QJsonValue &value, const QString &what);

// the following functions are higher level functions, that make use of the above functions for
// type conversion
template <typename T>
T ensureIsType(const QJsonValue &value, const T default_ = T(), const QString &what = "Value")
{
    if (value.isUndefined() || value.isNull())
    {
        return default_;
    }
    try
    {
        return requireIsType<T>(value, what);
    }
    catch (const JsonException &)
    {
        return default_;
    }
}

/// @throw JsonException
template <typename T>
T requireIsType(const QJsonObject &parent, const QString &key, const QString &what = "__placeholder__")
{
    const QString localWhat = QString(what).replace("__placeholder__", '\'' + key + '\'');
    if (!parent.contains(key))
    {
        throw JsonException(localWhat + "s parent does not contain " + localWhat);
    }
    return requireIsType<T>(parent.value(key), localWhat);
}

template <typename T>
T ensureIsType(const QJsonObject &parent, const QString &key, const T default_ = T(), const QString &what = "__placeholder__")
{
    const QString localWhat = QString(what).replace("__placeholder__", '\'' + key + '\'');
    if (!parent.contains(key))
    {
        return default_;
    }
    return ensureIsType<T>(parent.value(key), default_, localWhat);
}

template <typename T>
QVector<T> requireIsArrayOf(const QJsonDocument &doc)
{
    const QJsonArray array = requireArray(doc);
    QVector<T> out;
    for (const QJsonValue val : array)
    {
        out.append(requireIsType<T>(val, "Document"));
    }
    return out;
}

template <typename T>
QVector<T> ensureIsArrayOf(const QJsonValue &value, const QString &what = "Value")
{
    const QJsonArray array = ensureIsType<QJsonArray>(value, QJsonArray(), what);
    QVector<T> out;
    for (const QJsonValue val : array)
    {
        out.append(requireIsType<T>(val, what));
    }
    return out;
}

template <typename T>
QVector<T> ensureIsArrayOf(const QJsonValue &value, const QVector<T> default_, const QString &what = "Value")
{
    if (value.isUndefined())
    {
        return default_;
    }
    return ensureIsArrayOf<T>(value, what);
}

/// @throw JsonException
template <typename T>
QVector<T> requireIsArrayOf(const QJsonObject &parent, const QString &key, const QString &what = "__placeholder__")
{
    const QString localWhat = QString(what).replace("__placeholder__", '\'' + key + '\'');
    if (!parent.contains(key))
    {
        throw JsonException(localWhat + "s parent does not contain " + localWhat);
    }
    return ensureIsArrayOf<T>(parent.value(key), localWhat);
}

template <typename T>
QVector<T> ensureIsArrayOf(const QJsonObject &parent, const QString &key,
                         const QVector<T> &default_ = QVector<T>(), const QString &what = "__placeholder__")
{
    const QString localWhat = QString(what).replace("__placeholder__", '\'' + key + '\'');
    if (!parent.contains(key))
    {
        return default_;
    }
    return ensureIsArrayOf<T>(parent.value(key), default_, localWhat);
}

// this macro part could be replaced by variadic functions that just pass on their arguments, but that wouldn't work well with IDE helpers
#define JSON_HELPERFUNCTIONS(NAME, TYPE) \
    inline TYPE require##NAME(const QJsonValue &value, const QString &what = "Value") \
    { \
        return requireIsType<TYPE>(value, what); \
    } \
    inline TYPE ensure##NAME(const QJsonValue &value, const TYPE default_ = TYPE(), const QString &what = "Value") \
    { \
        return ensureIsType<TYPE>(value, default_, what); \
    } \
    inline TYPE require##NAME(const QJsonObject &parent, const QString &key, const QString &what = "__placeholder__") \
    { \
        return requireIsType<TYPE>(parent, key, what); \
    } \
    inline TYPE ensure##NAME(const QJsonObject &parent, const QString &key, const TYPE default_ = TYPE(), const QString &what = "__placeholder") \
    { \
        return ensureIsType<TYPE>(parent, key, default_, what); \
    }

JSON_HELPERFUNCTIONS(Array, QJsonArray)
JSON_HELPERFUNCTIONS(Object, QJsonObject)
JSON_HELPERFUNCTIONS(JsonValue, QJsonValue)
JSON_HELPERFUNCTIONS(String, QString)
JSON_HELPERFUNCTIONS(Boolean, bool)
JSON_HELPERFUNCTIONS(Double, double)
JSON_HELPERFUNCTIONS(Integer, int)
JSON_HELPERFUNCTIONS(DateTime, QDateTime)
JSON_HELPERFUNCTIONS(Url, QUrl)
JSON_HELPERFUNCTIONS(ByteArray, QByteArray)
JSON_HELPERFUNCTIONS(Dir, QDir)
JSON_HELPERFUNCTIONS(Uuid, QUuid)
JSON_HELPERFUNCTIONS(Variant, QVariant)

#undef JSON_HELPERFUNCTIONS

}
using JSONValidationError = Json::JsonException;