src/base/settingsstorage.h

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2016  Vladimir Golovnev <glassez@yandex.ru>
   4  * Copyright (C) 2014  sledgehammer999 <hammered999@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * In addition, as a special exception, the copyright holders give permission to
  21  * link this program with the OpenSSL project's "OpenSSL" library (or with
  22  * modified versions of it that use the same license as the "OpenSSL" library),
  23  * and distribute the linked executables. You must obey the GNU General Public
  24  * License in all respects for all of the code used other than "OpenSSL".  If you
  25  * modify file(s), you may extend this exception to your version of the file(s),
  26  * but you are not obligated to do so. If you do not wish to do so, delete this
  27  * exception statement from your version.
  28  */
  29
  30 #pragma once
  31
  32 #include <type_traits>
  33
  34 #include <QObject>
  35 #include <QReadWriteLock>
  36 #include <QTimer>
  37 #include <QVariantHash>
  38
  39 #include "path.h"
  40 #include "utils/string.h"
  41
  42 template <typename T>
  43 struct IsQFlags : std::false_type {};
  44
  45 template <typename T>
  46 struct IsQFlags<QFlags<T>> : std::true_type {};
  47
  48 class SettingsStorage : public QObject
  49 {
  50     Q_OBJECT
  51     SettingsStorage();
  52     ~SettingsStorage();
  53
  54 public:
  55     static void initInstance();
  56     static void freeInstance();
  57     static SettingsStorage *instance();
  58
  59     template <typename T>
  60     T loadValue(const QString &key, const T &defaultValue = {}) const
  61     {
  62         if constexpr (std::is_enum_v<T>)
  63         {
  64             const auto value = loadValue<QString>(key);
  65             return Utils::String::toEnum(value, defaultValue);
  66         }
  67         else if constexpr (IsQFlags<T>::value)
  68         {
  69             const typename T::Int value = loadValue(key, static_cast<typename T::Int>(defaultValue));
  70             return T {value};
  71         }
  72         else if constexpr (std::is_same_v<T, Path>)
  73         {
  74             const auto value = loadValue<QString>(key, defaultValue.toString());
  75             return Path(value);
  76         }
  77         else if constexpr (std::is_same_v<T, QVariant>)
  78         {
  79             // fast path for loading QVariant
  80             return loadValueImpl(key, defaultValue);
  81         }
  82         else
  83         {
  84             const QVariant value = loadValueImpl(key);
  85             // check if retrieved value is convertible to T
  86             return value.template canConvert<T>() ? value.template value<T>() : defaultValue;
  87         }
  88     }
  89
  90     template <typename T>
  91     void storeValue(const QString &key, const T &value)
  92     {
  93         if constexpr (std::is_enum_v<T>)
  94             storeValueImpl(key, Utils::String::fromEnum(value));
  95         else if constexpr (IsQFlags<T>::value)
  96             storeValueImpl(key, static_cast<typename T::Int>(value));
  97         else if constexpr (std::is_same_v<T, Path>)
  98             storeValueImpl(key, value.toString());
  99         else
 100             storeValueImpl(key, QVariant::fromValue(value));
 101     }
 102
 103     void removeValue(const QString &key);
 104     bool hasKey(const QString &key) const;
 105
 106 public slots:
 107     bool save();
 108
 109 private:
 110     QVariant loadValueImpl(const QString &key, const QVariant &defaultValue = {}) const;
 111     void storeValueImpl(const QString &key, const QVariant &value);
 112
 113     static SettingsStorage *m_instance;
 114
 115     bool m_dirty = false;
 116     QVariantHash m_data;
 117     QTimer m_timer;
 118     mutable QReadWriteLock m_lock;
 119 };