src/uisupport/widgethelpers.h

   1 /***************************************************************************
   2  *   Copyright (C) 2005-2018 by the Quassel Project                        *
   3  *   devel@quassel-irc.org                                                 *
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  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
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  20
  21 #pragma once
  22
  23 #include <algorithm>
  24 #include <initializer_list>
  25 #include <tuple>
  26 #include <utility>
  27
  28 #include <QAbstractButton>
  29 #include <QComboBox>
  30 #include <QDoubleSpinBox>
  31 #include <QGroupBox>
  32 #include <QLineEdit>
  33 #include <QObject>
  34 #include <QSpinBox>
  35 #include <QTextEdit>
  36
  37 #include "colorbutton.h"
  38 #include "fontselector.h"
  39 #include "funchelpers.h"
  40 #include "util.h"
  41
  42 namespace detail {
  43
  44 /**
  45  * Contains all supported widget changed signals.
  46  */
  47 static const auto supportedWidgetChangedSignals = std::make_tuple(
  48         &ColorButton::colorChanged,
  49         &FontSelector::fontChanged,
  50         &QAbstractButton::toggled,
  51         selectOverload<int>(&QComboBox::currentIndexChanged),
  52         selectOverload<double>(&QDoubleSpinBox::valueChanged),
  53         &QGroupBox::toggled,
  54         &QLineEdit::textChanged,
  55         selectOverload<int>(&QSpinBox::valueChanged),
  56         &QTextEdit::textChanged
  57 );
  58
  59 /**
  60  * Tries to find a changed signal that matches the given widget type, and connects that to the given receiver/slot.
  61  */
  62 template<typename Receiver, typename Slot, std::size_t... Is>
  63 bool tryConnectChangedSignal(const QObject* widget, const Receiver* receiver, Slot slot, std::index_sequence<Is...>)
  64 {
  65     // Tries to cast the given QObject to the given signal's class type, and connects to receiver/slot if successful.
  66     // If *alreadyConnected is true, just returns false to prevent multiple connections.
  67     static const auto tryConnect = [](const QObject* object, auto sig, auto receiver, auto slot, bool* alreadyConnected) {
  68         if (!*alreadyConnected) {
  69             auto widget = qobject_cast<const typename MemberFunction<decltype(sig)>::ClassType*>(object);
  70             if (widget) {
  71                 *alreadyConnected = QObject::connect(widget, sig, receiver, slot);
  72                 return *alreadyConnected;
  73             }
  74         }
  75         return false;
  76     };
  77
  78     // Unpack the tuple and try to connect to each contained signal in order
  79     bool alreadyConnected{false};
  80     auto results = {tryConnect(widget, std::get<Is>(supportedWidgetChangedSignals), receiver, slot, &alreadyConnected)...};
  81     return std::any_of(results.begin(), results.end(), [](bool result) { return result; });
  82 }
  83
  84 }  // namespace detail
  85
  86 /**
  87  * Connects the given widget's changed signal to the given receiver/context and slot.
  88  *
  89  * Changed signals for supported widgets are listed in detail::supportedWidgetChangedSignals.
  90  *
  91  * @note The slot must not take any arguments.
  92  *
  93  * @param widget   Pointer to the widget
  94  * @param receiver Receiver of the signal (or context for the connection)
  95  * @param slot     Receiving slot (or functor, or whatever)
  96  * @returns true if the widget type is supported, false otherwise
  97  */
  98 template<typename Receiver, typename Slot>
  99 bool connectToWidgetChangedSignal(const QObject* widget, const Receiver* receiver, Slot slot)
 100 {
 101     return detail::tryConnectChangedSignal(widget,
 102                                            receiver,
 103                                            slot,
 104                                            std::make_index_sequence<std::tuple_size<decltype(detail::supportedWidgetChangedSignals)>::value>{});
 105 }
 106
 107 /**
 108  * Connects the given widgets' changed signals to the given receiver/context and slot.
 109  *
 110  * Changed signals for supported widgets are listed in detail::supportedWidgetChangedSignals.
 111  *
 112  * @note The slot must not take any arguments.
 113  *
 114  * @param widget   Pointer to the widget
 115  * @param receiver Receiver of the signal (or context for the connection)
 116  * @param slot     Receiving slot (or functor, or whatever)
 117  * @returns true if all given widget types are supported, false otherwise
 118  */
 119 template<typename Container, typename Receiver, typename Slot>
 120 bool connectToWidgetsChangedSignals(const Container& widgets, const Receiver* receiver, Slot slot)
 121 {
 122     bool success = true;
 123     for (auto&& widget : widgets) {
 124         success &= detail::tryConnectChangedSignal(widget,
 125                                                    receiver,
 126                                                    slot,
 127                                                    std::make_index_sequence<
 128                                                        std::tuple_size<decltype(detail::supportedWidgetChangedSignals)>::value>{});
 129     }
 130     return success;
 131 }
 132
 133 /**
 134  * @overload
 135  * Convenience overload that allows brace-initializing the list of widgets.
 136  */
 137 template<typename Receiver, typename Slot>
 138 bool connectToWidgetsChangedSignals(const std::initializer_list<const QObject*>& widgets, const Receiver* receiver, Slot slot)
 139 {
 140     return connectToWidgetsChangedSignals(std::vector<const QObject*>{widgets}, receiver, slot);
 141 }