Add a thin layer around SettingsStorage class

This new layer would be handy for saving GUI widget states as they don't
need the value cached and they store/load rarely.

src/base/bittorrent/session.cpp

@@ -482,7 +482,7 @@ Session::Session(QObject *parent)
         m_storedCategories = map_cast(m_categories);
     }
 
-    m_tags = List::toSet(m_storedTags.value());
+    m_tags = List::toSet(m_storedTags.get());
 
     enqueueRefresh();
     updateSeedingLimitTimer();
@@ -1130,7 +1130,7 @@ void Session::initializeNativeSession()
 void Session::processBannedIPs(lt::ip_filter &filter)
 {
     // First, import current filter
-    for (const QString &ip : asConst(m_bannedIPs.value()))
+    for (const QString &ip : asConst(m_bannedIPs.get()))
     {
         lt::error_code ec;
         const lt::address addr = lt::make_address(ip.toLatin1().constData(), ec);
@@ -3142,7 +3142,7 @@ void Session::setPeerTurnoverInterval(const int val)
 
 int Session::asyncIOThreads() const
 {
-    return qBound(1, m_asyncIOThreads.value(), 1024);
+    return qBound(1, m_asyncIOThreads.get(), 1024);
 }
 
 void Session::setAsyncIOThreads(const int num)
@@ -3156,7 +3156,7 @@ void Session::setAsyncIOThreads(const int num)
 
 int Session::hashingThreads() const
 {
-    return qBound(1, m_hashingThreads.value(), 1024);
+    return qBound(1, m_hashingThreads.get(), 1024);
 }
 
 void Session::setHashingThreads(const int num)
@@ -3184,7 +3184,7 @@ void Session::setFilePoolSize(const int size)
 
 int Session::checkingMemUsage() const
 {
-    return qMax(1, m_checkingMemUsage.value());
+    return qMax(1, m_checkingMemUsage.get());
 }
 
 void Session::setCheckingMemUsage(int size)
@@ -3201,11 +3201,11 @@ void Session::setCheckingMemUsage(int size)
 int Session::diskCacheSize() const
 {
 #ifdef QBT_APP_64BIT
-    return qMin(m_diskCacheSize.value(), 33554431);  // 32768GiB
+    return qMin(m_diskCacheSize.get(), 33554431);  // 32768GiB
 #else
     // When build as 32bit binary, set the maximum at less than 2GB to prevent crashes
     // allocate 1536MiB and leave 512MiB to the rest of program data in RAM
-    return qMin(m_diskCacheSize.value(), 1536);
+    return qMin(m_diskCacheSize.get(), 1536);
 #endif
 }
 
@@ -3737,7 +3737,7 @@ bool Session::isListening() const
 
 MaxRatioAction Session::maxRatioAction() const
 {
-    return static_cast<MaxRatioAction>(m_maxRatioAction.value());
+    return static_cast<MaxRatioAction>(m_maxRatioAction.get());
 }
 
 void Session::setMaxRatioAction(const MaxRatioAction act)

src/base/settingvalue.h

@@ -30,80 +30,110 @@
 
 #include <type_traits>
 
-#include <QMetaEnum>
 #include <QString>
 
 #include "settingsstorage.h"
 #include "utils/string.h"
 
+// This is a thin/handy wrapper over `SettingsStorage`. Use it when store/load value
+// rarely occurs, otherwise use `CachedSettingValue`.
 template <typename T>
-class CachedSettingValue
+class SettingValue
 {
 public:
-    explicit CachedSettingValue(const char *keyName, const T &defaultValue = T())
+    explicit SettingValue(const char *keyName)
-        : m_keyName(QLatin1String(keyName))
+        : m_keyName {QLatin1String {keyName}}
-        , m_value(loadValue(defaultValue))
-    {
-    }
-
-    // The signature of the ProxyFunc should be equivalent to the following:
-    // T proxyFunc(const T &a);
-    template <typename ProxyFunc>
-    explicit CachedSettingValue(const char *keyName, const T &defaultValue
-                                , ProxyFunc &&proxyFunc)
-        : m_keyName(QLatin1String(keyName))
-        , m_value(proxyFunc(loadValue(defaultValue)))
     {
     }
 
-    T value() const
+    T get(const T &defaultValue = {}) const
     {
-        return m_value;
+        return load(defaultValue);
     }
 
     operator T() const
     {
-        return value();
+        return get();
     }
 
-    CachedSettingValue<T> &operator=(const T &newValue)
+    SettingValue<T> &operator=(const T &value)
     {
-        if (m_value == newValue)
+        store(value);
-            return *this;
-
-        m_value = newValue;
-        storeValue(m_value);
         return *this;
     }
 
 private:
-    // regular load/save pair
+    // regular load/store pair
     template <typename U, typename std::enable_if_t<!std::is_enum<U>::value, int> = 0>
-    U loadValue(const U &defaultValue)
+    U load(const U &defaultValue) const
     {
-        return SettingsStorage::instance()->loadValue(m_keyName, defaultValue).template value<T>();
+        return SettingsStorage::instance()->loadValue(m_keyName, defaultValue)
+            .template value<U>();
     }
 
     template <typename U, typename std::enable_if_t<!std::is_enum<U>::value, int> = 0>
-    void storeValue(const U &value)
+    void store(const U &value)
     {
         SettingsStorage::instance()->storeValue(m_keyName, value);
     }
 
-    // load/save pair for an enum
+    // load/store pair for enum type, saves literal value of the enum constant
-    // saves literal value of the enum constant, obtained from QMetaEnum
+    // TODO: merge the load/store functions with `if constexpr` in C++17
     template <typename U, typename std::enable_if_t<std::is_enum<U>::value, int> = 0>
-    U loadValue(const U &defaultValue)
+    U load(const U defaultValue) const
     {
-        return Utils::String::toEnum(SettingsStorage::instance()->loadValue(m_keyName).toString(), defaultValue);
+        return Utils::String::toEnum(load(QString {}), defaultValue);
     }
 
     template <typename U, typename std::enable_if_t<std::is_enum<U>::value, int> = 0>
-    void storeValue(const U &value)
+    void store(const U value)
     {
-        SettingsStorage::instance()->storeValue(m_keyName, Utils::String::fromEnum(value));
+        store(Utils::String::fromEnum(value));
     }
 
     const QString m_keyName;
-    T m_value;
+};
+
+template <typename T>
+class CachedSettingValue
+{
+public:
+    explicit CachedSettingValue(const char *keyName, const T &defaultValue = {})
+        : m_setting {keyName}
+        , m_cache {m_setting.get(defaultValue)}
+    {
+    }
+
+    // The signature of the ProxyFunc should be equivalent to the following:
+    // T proxyFunc(const T &a);
+    template <typename ProxyFunc>
+    explicit CachedSettingValue(const char *keyName, const T &defaultValue, ProxyFunc &&proxyFunc)
+        : m_setting {keyName}
+        , m_cache {proxyFunc(m_setting.get(defaultValue))}
+    {
+    }
+
+    T get() const
+    {
+        return m_cache;
+    }
+
+    operator T() const
+    {
+        return get();
+    }
+
+    CachedSettingValue<T> &operator=(const T &value)
+    {
+        if (m_cache == value)
+            return *this;
+
+        m_setting = value;
+        m_cache = value;
+        return *this;
+    }
+
+private:
+    SettingValue<T> m_setting;
+    T m_cache;
 };

src/base/torrentfileguard.cpp

@@ -73,7 +73,7 @@ void TorrentFileGuard::markAsAddedToSession()
 
 TorrentFileGuard::AutoDeleteMode TorrentFileGuard::autoDeleteMode()
 {
-    return autoDeleteModeSetting();
+    return autoDeleteModeSetting().get(AutoDeleteMode::Never);
 }
 
 void TorrentFileGuard::setAutoDeleteMode(TorrentFileGuard::AutoDeleteMode mode)
@@ -81,8 +81,8 @@ void TorrentFileGuard::setAutoDeleteMode(TorrentFileGuard::AutoDeleteMode mode)
     autoDeleteModeSetting() = mode;
 }
 
-CachedSettingValue<TorrentFileGuard::AutoDeleteMode> &TorrentFileGuard::autoDeleteModeSetting()
+SettingValue<TorrentFileGuard::AutoDeleteMode> &TorrentFileGuard::autoDeleteModeSetting()
 {
-    static CachedSettingValue<AutoDeleteMode> setting("Core/AutoDeleteAddedTorrentFile", AutoDeleteMode::Never);
+    static SettingValue<AutoDeleteMode> setting {"Core/AutoDeleteAddedTorrentFile"};
     return setting;
 }

src/base/torrentfileguard.h

@@ -31,7 +31,7 @@
 #include <QObject>
 #include <QString>
 
-template <typename T> class CachedSettingValue;
+template <typename T> class SettingValue;
 
 /// Utility class to defer file deletion
 class FileGuard
@@ -75,7 +75,7 @@ public:
 
 private:
     TorrentFileGuard(const QString &path, AutoDeleteMode mode);
-    static CachedSettingValue<AutoDeleteMode> &autoDeleteModeSetting();
+    static SettingValue<AutoDeleteMode> &autoDeleteModeSetting();
 
     Q_ENUM(AutoDeleteMode)
     AutoDeleteMode m_mode;

src/gui/addnewtorrentdialog.h

@@ -118,6 +118,6 @@ private:
     std::unique_ptr<TorrentFileGuard> m_torrentGuard;
     BitTorrent::AddTorrentParams m_torrentParams;
 
-    CachedSettingValue<QSize> m_storeDialogSize;
+    SettingValue<QSize> m_storeDialogSize;
-    CachedSettingValue<QByteArray> m_storeSplitterState;
+    SettingValue<QByteArray> m_storeSplitterState;
 };

src/gui/previewselectdialog.cpp

@@ -159,7 +159,7 @@ void PreviewSelectDialog::loadWindowState()
     Utils::Gui::resize(this, m_storeDialogSize);
 
     // Restore TreeView Header state
-    if (!m_storeTreeHeaderState.value().isEmpty())
+    if (!m_storeTreeHeaderState.get().isEmpty())
     {
         m_headerStateInitialized = m_ui->previewList->header()->restoreState(m_storeTreeHeaderState);
     }

src/gui/previewselectdialog.h

@@ -82,6 +82,6 @@ private:
     bool m_headerStateInitialized = false;
 
     // Settings
-    CachedSettingValue<QSize> m_storeDialogSize;
+    SettingValue<QSize> m_storeDialogSize;
-    CachedSettingValue<QByteArray> m_storeTreeHeaderState;
+    SettingValue<QByteArray> m_storeTreeHeaderState;
 };

src/gui/search/searchjobwidget.cpp

@@ -358,7 +358,7 @@ void SearchJobWidget::fillFilterComboBoxes()
     m_ui->filterMode->addItem(tr("Torrent names only"), static_cast<int>(NameFilteringMode::OnlyNames));
     m_ui->filterMode->addItem(tr("Everywhere"), static_cast<int>(NameFilteringMode::Everywhere));
 
-    QVariant selectedMode = static_cast<int>(nameFilteringModeSetting().value());
+    QVariant selectedMode = static_cast<int>(nameFilteringModeSetting().get(NameFilteringMode::OnlyNames));
     int index = m_ui->filterMode->findData(selectedMode);
     m_ui->filterMode->setCurrentIndex((index == -1) ? 0 : index);
 }
@@ -545,9 +545,9 @@ void SearchJobWidget::appendSearchResults(const QVector<SearchResult> &results)
     updateResultsCount();
 }
 
-CachedSettingValue<SearchJobWidget::NameFilteringMode> &SearchJobWidget::nameFilteringModeSetting()
+SettingValue<SearchJobWidget::NameFilteringMode> &SearchJobWidget::nameFilteringModeSetting()
 {
-    static CachedSettingValue<NameFilteringMode> setting("Search/FilteringMode", NameFilteringMode::OnlyNames);
+    static SettingValue<NameFilteringMode> setting {"Search/FilteringMode"};
     return setting;
 }
 

src/gui/search/searchjobwidget.h

@@ -43,7 +43,7 @@ class SearchHandler;
 class SearchSortModel;
 struct SearchResult;
 
-template <typename T> class CachedSettingValue;
+template <typename T> class SettingValue;
 
 namespace Ui
 {
@@ -117,7 +117,7 @@ private:
     void copyField(int column) const;
 
     static QString statusText(Status st);
-    static CachedSettingValue<NameFilteringMode> &nameFilteringModeSetting();
+    static SettingValue<NameFilteringMode> &nameFilteringModeSetting();
 
     Ui::SearchJobWidget *m_ui;
     SearchHandler *m_searchHandler;

src/gui/torrentcreatordialog.cpp

@@ -54,16 +54,16 @@ TorrentCreatorDialog::TorrentCreatorDialog(QWidget *parent, const QString &defau
     , m_storeStartSeeding(SETTINGS_KEY("StartSeeding"))
     , m_storeIgnoreRatio(SETTINGS_KEY("IgnoreRatio"))
 #if (LIBTORRENT_VERSION_NUM >= 20000)
-    , m_storeTorrentFormat(SETTINGS_KEY("TorrentFormat"), 1)
+    , m_storeTorrentFormat(SETTINGS_KEY("TorrentFormat"))
 #else
-    , m_storeOptimizeAlignment(SETTINGS_KEY("OptimizeAlignment"), true)
+    , m_storeOptimizeAlignment(SETTINGS_KEY("OptimizeAlignment"))
-    , m_paddedFileSizeLimit(SETTINGS_KEY("PaddedFileSizeLimit"), -1)
+    , m_paddedFileSizeLimit(SETTINGS_KEY("PaddedFileSizeLimit"))
 #endif
-    , m_storeLastAddPath(SETTINGS_KEY("LastAddPath"), QDir::homePath())
+    , m_storeLastAddPath(SETTINGS_KEY("LastAddPath"))
     , m_storeTrackerList(SETTINGS_KEY("TrackerList"))
     , m_storeWebSeedList(SETTINGS_KEY("WebSeedList"))
     , m_storeComments(SETTINGS_KEY("Comments"))
-    , m_storeLastSavePath(SETTINGS_KEY("LastSavePath"), QDir::homePath())
+    , m_storeLastSavePath(SETTINGS_KEY("LastSavePath"))
     , m_storeSource(SETTINGS_KEY("Source"))
 {
     m_ui->setupUi(this);
@@ -184,7 +184,7 @@ void TorrentCreatorDialog::onCreateButtonClicked()
     input = fi.canonicalFilePath();
 
     // get save path
-    const QString savePath = QString(m_storeLastSavePath) + QLatin1Char('/') + fi.fileName() + QLatin1String(".torrent");
+    const QString savePath = m_storeLastSavePath.get(QDir::homePath()) + QLatin1Char('/') + fi.fileName() + QLatin1String(".torrent");
     QString destination = QFileDialog::getSaveFileName(this, tr("Select where to save the new torrent"), savePath, tr("Torrent Files (*.torrent)"));
     if (destination.isEmpty())
         return;
@@ -324,7 +324,7 @@ void TorrentCreatorDialog::saveSettings()
 
 void TorrentCreatorDialog::loadSettings()
 {
-    m_ui->textInputPath->setText(m_storeLastAddPath);
+    m_ui->textInputPath->setText(m_storeLastAddPath.get(QDir::homePath()));
 
     m_ui->comboPieceSize->setCurrentIndex(m_storePieceSize);
     m_ui->checkPrivate->setChecked(m_storePrivateTorrent);
@@ -332,10 +332,10 @@ void TorrentCreatorDialog::loadSettings()
     m_ui->checkIgnoreShareLimits->setChecked(m_storeIgnoreRatio);
     m_ui->checkIgnoreShareLimits->setEnabled(m_ui->checkStartSeeding->isChecked());
 #if (LIBTORRENT_VERSION_NUM >= 20000)
-    m_ui->comboTorrentFormat->setCurrentIndex(m_storeTorrentFormat);
+    m_ui->comboTorrentFormat->setCurrentIndex(m_storeTorrentFormat.get(1));
 #else
-    m_ui->checkOptimizeAlignment->setChecked(m_storeOptimizeAlignment);
+    m_ui->checkOptimizeAlignment->setChecked(m_storeOptimizeAlignment.get(true));
-    m_ui->spinPaddedFileSizeLimit->setValue(m_paddedFileSizeLimit);
+    m_ui->spinPaddedFileSizeLimit->setValue(m_paddedFileSizeLimit.get(-1));
 #endif
 
     m_ui->trackersList->setPlainText(m_storeTrackerList);

src/gui/torrentcreatordialog.h

@@ -78,21 +78,21 @@ private:
     BitTorrent::TorrentCreatorThread *m_creatorThread;
 
     // settings
-    CachedSettingValue<QSize> m_storeDialogSize;
+    SettingValue<QSize> m_storeDialogSize;
-    CachedSettingValue<int> m_storePieceSize;
+    SettingValue<int> m_storePieceSize;
-    CachedSettingValue<bool> m_storePrivateTorrent;
+    SettingValue<bool> m_storePrivateTorrent;
-    CachedSettingValue<bool> m_storeStartSeeding;
+    SettingValue<bool> m_storeStartSeeding;
-    CachedSettingValue<bool> m_storeIgnoreRatio;
+    SettingValue<bool> m_storeIgnoreRatio;
 #if (LIBTORRENT_VERSION_NUM >= 20000)
-    CachedSettingValue<int> m_storeTorrentFormat;
+    SettingValue<int> m_storeTorrentFormat;
 #else
-    CachedSettingValue<bool> m_storeOptimizeAlignment;
+    SettingValue<bool> m_storeOptimizeAlignment;
-    CachedSettingValue<int> m_paddedFileSizeLimit;
+    SettingValue<int> m_paddedFileSizeLimit;
 #endif
-    CachedSettingValue<QString> m_storeLastAddPath;
+    SettingValue<QString> m_storeLastAddPath;
-    CachedSettingValue<QString> m_storeTrackerList;
+    SettingValue<QString> m_storeTrackerList;
-    CachedSettingValue<QString> m_storeWebSeedList;
+    SettingValue<QString> m_storeWebSeedList;
-    CachedSettingValue<QString> m_storeComments;
+    SettingValue<QString> m_storeComments;
-    CachedSettingValue<QString> m_storeLastSavePath;
+    SettingValue<QString> m_storeLastSavePath;
-    CachedSettingValue<QString> m_storeSource;
+    SettingValue<QString> m_storeSource;
 };

src/gui/trackerentriesdialog.h

@@ -60,5 +60,5 @@ private:
     void loadSettings();
 
     Ui::TrackerEntriesDialog *m_ui;
-    CachedSettingValue<QSize> m_storeDialogSize;
+    SettingValue<QSize> m_storeDialogSize;
 };