options/value: add `QObject::connect` wrapper

This is useful not just to save on complexity in call sites, but also
because I plan on using the Verdigris library to remove needless
`valueChanged()` and `setValue()` overloads from each `value<t>`
instance.

Also fix a bug in `options/tie.hpp` where `QComboBox::setCurrentIndex`
was erroneously called as `Qt::DirectConnection`.

5 files changed, 74 insertions, 71 deletions

diff --git a/options/base-value.hpp b/options/base-value.hpp
index eb8c89b7..81da0513 100644
--- a/options/base-value.hpp
+++ b/options/base-value.hpp
@@ -10,6 +10,7 @@
 #include "value-traits.hpp"
 
 #include <utility>
+#include <type_traits>
 
 #include <QObject>
 #include <QString>
@@ -26,21 +27,15 @@ class OTR_OPTIONS_EXPORT value_ : public QObject
 {
     Q_OBJECT
 
-    template<typename t> using cv_qualified = detail::cv_qualified<t>;
-    template<typename t>
-    using signal_sig = void(value_::*)(cv_qualified<t>) const;
+protected:
+    template<typename t> using signal_sig_ = void(value_::*)(detail::cv_qualified<detail::maybe_enum_type_t<t>>) const;
+    template<typename t> using slot_sig_ = void(value_::*)(detail::cv_qualified<detail::maybe_enum_type_t<t>>);
 
 public:
     QString name() const { return self_name; }
     value_(bundle const& b, const QString& name) noexcept;
     ~value_() override;
 
-    template<typename t>
-    static constexpr auto value_changed()
-    {
-        return static_cast<signal_sig<t>>(&value_::valueChanged);
-    }
-
     static const bool TRACE_NOTIFY;
 
 signals:
diff --git a/options/tie.cpp b/options/tie.cpp
index 493ff551..0ac1c5bf 100644
--- a/options/tie.cpp
+++ b/options/tie.cpp
@@ -8,7 +8,6 @@
 
 #include "tie.hpp"
 #include "compat/run-in-thread.hpp"
-#include "compat/macros.hpp"
 
 #include "value-traits.hpp"
 
@@ -20,16 +19,16 @@ void tie_setting(value<int>& v, QComboBox* cb)
 {
     cb->setCurrentIndex(v);
     v = cb->currentIndex();
-    value_::connect(cb, SIGNAL(currentIndexChanged(int)), &v, SLOT(setValue(int)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(int)), cb, SLOT(setCurrentIndex(int)), v.SAFE_CONNTYPE);
+    v.connect_to(cb, &QComboBox::setCurrentIndex);
+    v.connect_from(cb, static_cast<void(QComboBox::*)(int)>(&QComboBox::currentIndexChanged));
 }
 
 void tie_setting(value<QString>& v, QComboBox* cb)
 {
     cb->setCurrentText(v);
     v = cb->currentText();
-    value_::connect(cb, SIGNAL(currentTextChanged(QString)), &v, SLOT(setValue(const QString&)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(const QString&)), cb, SLOT(setCurrentText(const QString&)), v.SAFE_CONNTYPE);
+    v.connect_to(cb, &QComboBox::currentTextChanged);
+    v.connect_from(cb, &QComboBox::setCurrentText);
 }
 
 void tie_setting(value<QVariant>& v, QComboBox* cb)
@@ -57,60 +56,57 @@ void tie_setting(value<QVariant>& v, QComboBox* cb)
     else
         v = {};
 
-    value_::connect(cb, static_cast<void(QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
-                    &v, [cb, &v](int idx) { v = cb->itemData(idx); },
-                    v.DIRECT_CONNTYPE);
-    value_::connect(&v, value_::value_changed<QVariant>(),
-                    cb, [set_idx](const QVariant& var) { set_idx(var); },
-                    v.SAFE_CONNTYPE);
+    v.connect_from(cb, static_cast<void(QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
+                   [cb, &v](int idx) { v = cb->itemData(idx); });
+    v.connect_to(cb, [fn = std::move(set_idx)](const QVariant& var) { fn(var); });
 }
 
 void tie_setting(value<bool>& v, QRadioButton* cb)
 {
     cb->setChecked(v);
-    value_::connect(cb, SIGNAL(toggled(bool)), &v, SLOT(setValue(bool)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(bool)), cb, SLOT(setChecked(bool)), v.SAFE_CONNTYPE);
+    v.connect_to(cb, &QRadioButton::setChecked);
+    v.connect_from(cb, &QRadioButton::toggled);
 }
 
 void tie_setting(value<bool>& v, QCheckBox* cb)
 {
     cb->setChecked(v);
-    value_::connect(cb, SIGNAL(toggled(bool)), &v, SLOT(setValue(bool)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(bool)), cb, SLOT(setChecked(bool)), v.SAFE_CONNTYPE);
+    v.connect_to(cb, &QCheckBox::setChecked);
+    v.connect_from(cb, &QCheckBox::toggled);
 }
 
 void tie_setting(value<double>& v, QDoubleSpinBox* dsb)
 {
     dsb->setValue(v);
-    value_::connect(dsb, SIGNAL(valueChanged(double)), &v, SLOT(setValue(double)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(double)), dsb, SLOT(setValue(double)), v.SAFE_CONNTYPE);
+    v.connect_to(dsb, &QDoubleSpinBox::setValue);
+    v.connect_from(dsb, static_cast<void(QDoubleSpinBox::*)(double)>(&QDoubleSpinBox::valueChanged));
 }
 
 void tie_setting(value<int>& v, QSpinBox* sb)
 {
     sb->setValue(v);
-    value_::connect(sb, SIGNAL(valueChanged(int)), &v, SLOT(setValue(int)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(int)), sb, SLOT(setValue(int)), v.SAFE_CONNTYPE);
+    v.connect_to(sb, &QSpinBox::setValue);
+    v.connect_from(sb, static_cast<void(QSpinBox::*)(int)>(&QSpinBox::valueChanged));
 }
 
 void tie_setting(value<QString>& v, QLineEdit* le)
 {
     le->setText(v);
-    value_::connect(le, SIGNAL(textChanged(QString)), &v, SLOT(setValue(QString)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, value_::value_changed<QString>(), le, &QLineEdit::setText, v.SAFE_CONNTYPE);
+    v.connect_to(le, &QLineEdit::setText);
+    v.connect_from(le, &QLineEdit::textChanged);
 }
 
 void tie_setting(value<QString>& v, QLabel* lb)
 {
     lb->setText(v);
-    value_::connect(&v, value_::value_changed<QString>(), lb, &QLabel::setText, v.SAFE_CONNTYPE);
+    v.connect_to(lb, &QLabel::setText);
 }
 
 void tie_setting(value<int>& v, QTabWidget* t)
 {
     t->setCurrentIndex(v);
-    value_::connect(t, SIGNAL(currentChanged(int)), &v, SLOT(setValue(int)), v.DIRECT_CONNTYPE);
-    value_::connect(&v, SIGNAL(valueChanged(int)), t, SLOT(setCurrentIndex(int)), v.SAFE_CONNTYPE);
+    v.connect_to(t, &QTabWidget::setCurrentIndex);
+    v.connect_from(t, &QTabWidget::currentChanged);
 }
 
 void tie_setting(value<slider_value>& v, QSlider* w)
@@ -123,32 +119,24 @@ void tie_setting(value<slider_value>& v, QSlider* w)
         v = v().update_from_slider(w->value(), q_min, q_max);
     }
 
-    value_::connect(w, &QSlider::valueChanged, &v, [=, &v](int pos)
-    {
-        run_in_thread_sync(w, [&]()
-        {
+    v.connect_from(w, &QSlider::valueChanged, [=, &v](int pos) {
+        run_in_thread_sync(w, [&]() {
             const int q_min = w->minimum();
             const int q_max = w->maximum();
             v = v().update_from_slider(pos, q_min, q_max);
             w->setValue(v().to_slider_pos(q_min, q_max));
         });
-    },
-    v.DIRECT_CONNTYPE);
-
-    value_::connect(&v,
-                    value_::value_changed<slider_value>(),
-                    w,
-                    [=, &v](double) {
-        run_in_thread_sync(w, [=, &v]()
-        {
+    }, v.DIRECT_CONNTYPE);
+
+    v.connect_to(w, [=, &v](double) {
+        run_in_thread_sync(w, [=, &v]() {
             const int q_min = w->minimum();
             const int q_max = w->maximum();
             const int pos = v->to_slider_pos(q_min, q_max);
             v = v->update_from_slider(pos, q_min, q_max);
             w->setValue(pos);
         });
-    },
-    v.DIRECT_CONNTYPE);
+    }, v.DIRECT_CONNTYPE);
 }
 
 } // ns options
diff --git a/options/tie.hpp b/options/tie.hpp
index 46ade075..81567139 100644
--- a/options/tie.hpp
+++ b/options/tie.hpp
@@ -37,13 +37,9 @@ std::enable_if_t<std::is_enum_v<t>> tie_setting(value<t>& v, QComboBox* cb)
     cb->setCurrentIndex(cb->findData(int(static_cast<t>(v))));
     v = static_cast<t>(cb->currentData().toInt());
 
-    value_::connect(cb, static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
-                    &v, [&v, cb](int idx) { v = static_cast<t>(cb->itemData(idx).toInt()); },
-                    v.DIRECT_CONNTYPE);
-
-    value_::connect(&v, value_::value_changed<int>(),
-                    cb, [cb](int x) { cb->setCurrentIndex(cb->findData(x)); },
-                    v.SAFE_CONNTYPE);
+    v.connect_from(cb, static_cast<void(QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
+                   [&v, cb](int idx) { v = static_cast<t>(cb->itemData(idx).toInt()); });
+    v.connect_to(cb, [cb](int x) { cb->setCurrentIndex(cb->findData(x)); });
 }
 
 template<typename t, typename From, typename To>
@@ -52,23 +48,20 @@ void tie_setting(value<t>& v, QComboBox* cb, From&& fn_to_index, To&& fn_to_valu
     cb->setCurrentIndex(fn_to_index(v));
     v = fn_to_value(cb->currentIndex(), cb->currentData());
 
-    value_::connect(cb, static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
-                    &v, [&v, cb, fn_to_value](int idx) { v = fn_to_value(idx, cb->currentData()); },
-                    v.DIRECT_CONNTYPE);
-    value_::connect(&v, value_::value_changed<t>(),
-                    cb, [cb, fn_to_index](detail::cv_qualified<t>& v) { cb->setCurrentIndex(fn_to_index(v)); },
-                    v.DIRECT_CONNTYPE);
+    v.connect_from(cb, static_cast<void(QComboBox::*)(int)>(&QComboBox::currentIndexChanged),
+                   [&v, cb, fn = std::forward<To>(fn_to_value)](int idx) { v = fn(idx, cb->currentData()); });
+    v.connect_to(cb, [cb, fn = std::forward<From>(fn_to_index)](detail::cv_qualified<t> v) { cb->setCurrentIndex(fn(v)); });
 }
 
 template<typename t, typename F>
 void tie_setting(value<t>& v, QLabel* lb, F&& fun)
 {
-    auto closure = [lb, fun](detail::cv_qualified<t> v) { lb->setText(fun(v)); };
+    auto closure = [lb, fn = std::forward<F>(fun)](detail::cv_qualified<t> v) {
+        lb->setText(fn(v));
+    };
 
     closure(v());
-    value_::connect(&v, value_::value_changed<t>(),
-                    lb, closure,
-                    v.SAFE_CONNTYPE);
+    v.connect_to(lb, std::move(closure));
 }
 
 template<typename t, typename F>
@@ -78,10 +71,7 @@ void tie_setting(value<t>& v, QObject* obj, F&& fun)
         abort();
 
     fun(v());
-
-    value_::connect(&v, value_::value_changed<t>(),
-                    obj, fun,
-                    v.DIRECT_CONNTYPE);
+    v.connect_to(obj, std::forward<F>(fun));
 }
 
 OTR_OPTIONS_EXPORT void tie_setting(value<int>& v, QComboBox* cb);
diff --git a/options/value-traits.hpp b/options/value-traits.hpp
index 145cd924..e676f942 100644
--- a/options/value-traits.hpp
+++ b/options/value-traits.hpp
@@ -15,6 +15,17 @@ using cv_qualified =
                        std::remove_cvref_t<t>,
                        std::add_lvalue_reference_t<std::add_const_t<std::remove_cvref_t<t>>>>;
 
+template<typename t, typename = void>
+struct maybe_enum_type {
+    using type = t;
+};
+template<typename t>
+struct maybe_enum_type<t, std::enable_if_t<std::is_enum_v<t>>> {
+    using type = int;
+};
+
+template<typename t> using maybe_enum_type_t = typename maybe_enum_type<t>::type;
+
 template<typename t, typename u = t, typename Enable = void>
 struct default_value_traits
 {
diff --git a/options/value.hpp b/options/value.hpp
index 090a7bdf..4476f8b7 100644
--- a/options/value.hpp
+++ b/options/value.hpp
@@ -27,10 +27,10 @@ namespace options::detail {
     {
         t x;
     public:
-        constexpr t const* operator->() const { return &x; }
         constexpr t* operator->() { return &x; }
         constexpr explicit dereference_wrapper(t&& x) : x(x) {}
     };
+    template<typename t, typename...> /*MSVC workaround*/ static constexpr bool is_enum_v = std::is_enum_v<t>;
 } // ns options::detail
 
 namespace options {
@@ -38,7 +38,7 @@ namespace options {
 template<typename t>
 class value final : public value_
 {
-    static_assert(std::is_same_v<t, remove_cvref_t<t>>);
+    static_assert(std::is_same_v<t, std::remove_cvref_t<t>>);
     mutable QMutex mtx;
     const t def;
     mutable t cached_value;
@@ -86,6 +86,9 @@ class value final : public value_
     }
 
 public:
+    using signal_sig = typename value_::signal_sig_<t>;
+    using slot_sig = typename value_::slot_sig_<t>;
+
     QVariant get_variant() const noexcept override
     {
         if (QVariant ret{b->get_variant(self_name)}; ret.isValid() && !ret.isNull())
@@ -195,6 +198,22 @@ public:
     {
         return static_cast<u>(get());
     }
+
+    template<typename Q, typename F>
+    QMetaObject::Connection
+    connect_to(Q* qobject, F&& writer, Qt::ConnectionType conn = Qt::QueuedConnection) {
+        return QObject::connect(this, static_cast<signal_sig>(&value<t>::valueChanged), qobject, std::forward<F>(writer), conn);
+    }
+    template<typename Q, typename F>
+    QMetaObject::Connection
+    connect_from(Q* qobject, F&& reader, Qt::ConnectionType conn = Qt::DirectConnection) {
+        return QObject::connect(qobject, std::forward<F>(reader), this, static_cast<slot_sig>(&value<t>::setValue), conn);
+    }
+    template<typename Q, typename F, typename G>
+    QMetaObject::Connection
+    connect_from(Q* qobject, F&& reader, G&& fn, Qt::ConnectionType conn = Qt::DirectConnection) {
+        return QObject::connect(qobject, std::forward<F>(reader), this, std::forward<G>(fn), conn);
+    }
 };
 
 #if !defined OTR_OPTIONS_INST_VALUE