ADataBinding.h

/*
 * AUI Framework - Declarative UI toolkit for modern C++20
 * Copyright (C) 2020-2025 Alex2772 and Contributors
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
#pragma once
 
#include "AUI/Traits/concepts.h"
#include "ALayoutInflater.h"
#include <functional>
#include <type_traits>
#include <AUI/Common/SharedPtr.h>
#include <AUI/Common/ASignal.h>
#include <AUI/Traits/members.h>
#include <AUI/View/AViewContainer.h>
 

template<typename View, typename FieldType>
struct ADataBindingDefault {
public:
   static void setup(const _<View>& view) {}

   static auto property(const _<View>& view) {}

   [[deprecated("ADataBinding is deprecated. Please use Property System to bind values")]]
   static ASignal<FieldType>(View::*getGetter()) {
       return nullptr;
   }

   [[deprecated("ADataBinding is deprecated. Please use Property System to bind values")]]
   static void(View::*getSetter())(const FieldType& v) {
       return nullptr;
   }
};
 
template<aui::derived_from<AViewContainer> Container>
struct ADataBindingDefault<Container, _<AView>> {
   static void setup(const _<AViewContainer>& container) {}
   static auto property(const _<AViewContainer>& container) {
       return ASlotDef {
           container.get(),
           [&container = *container](const _<AView>& viewToInflate) {
               ALayoutInflater::inflate(container, viewToInflate);
           },
       };
   }
};
 
template <typename Model>
class ADataBinding;
 
template<typename Model, typename View, typename ModelField, typename Getter, aui::invocable<View*, const ModelField&> Setter>
class ADataBindingLinker {
private:
   ADataBinding<Model>* mBinder;
   Setter setter;
   std::decay_t<ModelField>(Model::*mField);
   ASignal<std::decay_t<Getter>>(View::*mGetter);
 
public:
   ADataBindingLinker(ADataBinding<Model>* binder, ASignal<std::decay_t<Getter>>(View::*getter), Setter setter,
                      std::decay_t<ModelField>(Model::*field)):
           mBinder(binder), mGetter(getter), setter(std::move(setter)), mField(field) {}
 
   ADataBinding<Model>* getBinder() const {
       return mBinder;
   }
 
   auto getSetterFunc() const {
       return setter;
   }
 
   auto getField() const {
       return mField;
   }
 
   auto getGetter() const {
       return mGetter;
   }
};
template<typename Model, typename Data, typename Projection>
class ADataBindingLinker2 {
private:
   ADataBinding<Model>* mBinder;
   Data(Model::*mField);
   Projection mProjection;
 
public:
   ADataBindingLinker2(ADataBinding<Model>* binder, Data(Model::*field), Projection projection = nullptr) : mBinder(binder), mField(field), mProjection(std::move(projection)) {}
 
   ADataBinding<Model>* getBinder() const {
       return mBinder;
   }
 
   auto getField() const {
       return mField;
   }
 
   Projection getProjection() const {
       return mProjection;
   }
};

template <typename Model>
class [[deprecated("consider using AProperty and signal/slot connections instead")]] ADataBinding: public AObject {
private:
   using Observer = std::function<void(const Model& model, unsigned)>;
   ADeque<Observer> mLinkObservers;
 
   Model* mModel = nullptr;
   bool mOwning = false;
 
   void* mExcept = nullptr;
 
public:
 
   ADataBinding() = default;
   explicit ADataBinding(const Model& m)
   {
       setModel(m);
   }
   explicit ADataBinding(Model* m)
   {
       setModel(m);
   }
 
   virtual ~ADataBinding() {
       if (mOwning) {
           delete mModel;
       }
   }

   template<typename View, typename ModelField, typename SetterArg>
   auto operator()(ModelField(Model::*field), void(View::*setterFunc)(SetterArg)) {
       AUI_ASSERT(setterFunc != nullptr);
       return operator()<View, ModelField>(field, (ASignal<ModelField>(View::*))nullptr, setterFunc);
   }

   template<typename ModelField, typename SetterLambda>
   auto operator()(ModelField(Model::*field), SetterLambda setterLambda) {
       using lambda_args = typename aui::lambda_info<SetterLambda>::args;
       return aui::tuple_visitor<lambda_args>::for_each_all([&]<typename ViewReference, typename DataArgument>() {
           static_assert(std::is_reference_v<ViewReference>, "View is expected to be a reference");
           static_assert(aui::convertible_to<ModelField, DataArgument>, "lambda's argument is expected to be constructible from ModelField");
           using View = std::decay_t<ViewReference>;
           return operator()<View, ModelField>(field, (ASignal<ModelField>(View::*))nullptr, [setterLambda = std::move(setterLambda)](View* view, DataArgument dataArgument) {
               std::invoke(setterLambda, *view, std::forward<DataArgument>(dataArgument));
           });
       });
   }

   template<typename View, typename ModelField, typename GetterRV, aui::invocable<View*, const ModelField&> Setter>
   auto operator()(ModelField(Model::*field),
                   ASignal<GetterRV>(View::*getter),
                   Setter setter = (void(View::*)(const ModelField&))nullptr) {
       return ADataBindingLinker<Model, View, std::decay_t<ModelField>, GetterRV, Setter>(this, getter, std::move(setter), field);
   }

   template<typename Data>
   auto operator()(Data(Model::*field)) {
       return ADataBindingLinker2<Model, Data, std::nullptr_t>(this, field, nullptr);
   }

   template<typename Data, aui::invocable<Data> Projection>
   ADataBindingLinker2<Model, Data, Projection> operator()(Data(Model::*field), Projection projection) {
       return ADataBindingLinker2<Model, Data, Projection>(this, field, std::move(projection));
   }
   const Model& getModel() const noexcept {
       return *mModel;
   }
 
   Model const * operator->() const noexcept {
       return &getModel();
   }
 
   Model& getEditableModel() {
       return *mModel;
   }
   void setModel(const Model& model) {
       if (mOwning) {
           delete mModel;
       }
       mOwning = true;
       mModel = new Model(model);
       notifyUpdate();
   }
 
   void setModel(Model* model) {
       if (mOwning) {
           delete mModel;
       }
       mOwning = false;
       mModel = model;
       notifyUpdate();
   }
 
   const void* getExclusion() const {
       return mExcept;
   }
 
   void notifyUpdate(void* except = nullptr, unsigned field = -1) {
       mExcept = except;
       for (auto& applier : mLinkObservers) {
           applier(*mModel, field);
       }
       emit modelChanged;
   }
 
   template<typename ModelField>
   void notifyUpdate(ModelField(Model::*field)) {
       union converter {
           unsigned i;
           decltype(field) p;
       } c;
       c.p = field;
       notifyUpdate(nullptr, c.i);
   }
 
   template<typename ModelField, aui::convertible_to<ModelField> U>
   void setValue(ModelField(Model::*field), U&& value) {
       mModel->*field = std::move(value);
       notifyUpdate(field);
   }
 
   void addObserver(Observer applier) {
       mLinkObservers << std::move(applier);
       if (mModel) {
           mLinkObservers.last()(*mModel, -1);
       }
   }
 
   template<aui::invocable T>
   void addObserver(T&& applier) {
       addObserver([applier = std::forward<T>(applier)](const Model&, unsigned) {
           applier();
       });
   }
 
   template<typename ModelField, typename FieldObserver>
   void addObserverNoInitialCall(ModelField(Model::*field), FieldObserver&& observer) {
       mLinkObservers << [observer = std::forward<FieldObserver>(observer), field](const Model& model, unsigned index) {
           union converter {
               unsigned i;
               decltype(field) p;
           } c;
           c.p = field;
           if (c.i == index || index == -1) {
               observer(model.*field);
           }
       };
   }
   template<typename ModelField, typename FieldObserver>
   void addObserver(ModelField(Model::*field), FieldObserver&& observer) {
       addObserverNoInitialCall(field, std::forward<FieldObserver>(observer));
       if (mModel) {
           mLinkObservers.last()(*mModel, -1);
       }
   }
 
 
signals:
   emits<> modelChanged;
};
 
template<typename Klass1, typename View, typename Model, typename ModelField, typename GetterRV, typename SetterArg>
_<Klass1> operator&&(const _<Klass1>& modelBinding, const ADataBindingLinker<Model, View, ModelField, GetterRV, SetterArg>& linker) {
   union converter {
       unsigned i;
       decltype(linker.getField()) p;
   };
   if (linker.getGetter()) {
       AObject::connect(modelBinding.get()->*(linker.getGetter()), linker.getBinder(), [modelBinding, linker](const GetterRV& data) {
           AUI_ASSERTX(&linker.getBinder()->getEditableModel(), "please setModel for ADataBinding");
           modelBinding->setSignalsEnabled(false);
           linker.getBinder()->getEditableModel().*(linker.getField()) = data;
           converter c;
           c.p = linker.getField();
           linker.getBinder()->notifyUpdate(modelBinding.get(), c.i);
           modelBinding->setSignalsEnabled(true);
       });
   }
 
   if constexpr (aui::convertible_to<decltype(linker.getSetterFunc()), bool>) {
       if (!bool(linker.getSetterFunc())) {
           return modelBinding;
       }
   }
   linker.getBinder()->addObserver([modelBinding, linker](const Model& model, unsigned field) {
       converter c;
       c.p = linker.getField();
       if (c.i == field || field == -1) {
           if (modelBinding.get() != linker.getBinder()->getExclusion()) {
               std::invoke(linker.getSetterFunc(), modelBinding.get(), model.*(linker.getField()));
           }
       }
   });
 
   return modelBinding;
}
 
 
namespace aui::detail {
   template<typename ForcedClazz, typename Type>
   struct pointer_to_member {
       template<typename... Args>
       static Type(ForcedClazz::*with_args(std::tuple<Args...>))(Args...) {
           return nullptr;
       }
   };
}
 
template<typename View, typename Model, typename Data, typename Projection>
_<View> operator&&(const _<View>& object, const ADataBindingLinker2<Model, Data, Projection>& linker) {
   ADataBindingDefault<View, Data>::setup(object);
 
   constexpr bool is_default_projection = std::is_same_v<Projection, std::nullptr_t>;
   using projection_deduced = std::conditional_t<is_default_projection, aui::identity, Projection>;
   static_assert(std::is_invocable_v<projection_deduced, Data>, "projection is expected to accept Data value from model");
   using data_deduced = std::decay_t<std::invoke_result_t<projection_deduced, Data>>;
 
   using getter = ASignal<Data>(View::*);
   using setter = aui::reflect::member<decltype(ADataBindingDefault<View, data_deduced>::getSetter())>;
 
   using setter_ret = typename setter::return_t;
   using setter_args = typename setter::args;
 
   using my_pointer_to_member = typename aui::detail::pointer_to_member<View, setter_ret>;
 
   using pointer_to_setter = decltype(my_pointer_to_member::with_args(std::declval<setter_args>()));
 
   if constexpr (is_default_projection) {
       getter g = nullptr;
       // getter is optional.
       if constexpr (requires { ADataBindingDefault<View, Data>::getGetter(); }) {
           if constexpr (requires { std::invoke(ADataBindingDefault<View, Data>::getGetter(), *object).changed; }) {
               // AProperty.
               g = (getter) &std::invoke(ADataBindingDefault<View, Data>::getGetter(), *object).changed; // BROKEN -- https://github.com/aui-framework/aui/discussions/442
           } else {
               g = (getter) &std::invoke(ADataBindingDefault<View, Data>::getGetter(), *object); // BROKEN -- https://github.com/aui-framework/aui/discussions/442
           }
       }
       auto s = static_cast<pointer_to_setter>(ADataBindingDefault<View, Data>::getSetter());
 
       AUI_ASSERTX(g != nullptr || s != nullptr, "ADataBindingDefault is not defined for View, Data");
 
       object && (*linker.getBinder())(linker.getField(), g, s);
   } else {
       object && (*linker.getBinder())(linker.getField(), [projection = linker.getProjection()](View& v, const Data& d) {
           auto s = static_cast<pointer_to_setter>(ADataBindingDefault<View, data_deduced>::getSetter());
           std::invoke(s, &v, projection(d));
       });
   }
   return object;
}
 
template<typename View>
struct ADataBindingDefault<View, Visibility> {
public:
   static void setup(const _<View>& view) {}
 
   static auto getSetter() {
       return &AView::setVisibility;
   }
};
 
template <typename Object, APropertyReadable Connectable>
inline const _<Object>& operator&(const _<Object>& object, Connectable&& binding) {
   aui::tuple_visitor<
       typename AAnySignalOrPropertyTraits<std::decay_t<Connectable>>::args>::for_each_all([&]<typename... T>() {
       using Binding = ADataBindingDefault<std::decay_t<Object>, std::decay_t<T>...>;
       static_assert(
           requires { { Binding::property(object) } -> AAnyProperty; } ||
               requires { { Binding::property(object) } -> aui::derived_from<ASlotDefBase>; },
           "ADataBindingDefault is required to have property() function to return any property or slot def; either "
           "define proper ADataBindingDefault specialization or explicitly specify the destination property.");
       static_assert(
           requires { { Binding::setup(object) }; },
           "ADataBindingDefault is required to have setup(const _<Object>&) function; either define proper "
           "ADataBindingDefault specialization or explicitly specify the destination property.");
       Binding::setup(object);
       AObject::connect(binding, Binding::property(object));
   });
   return object;
}
 
template<typename Object, APropertyWritable Connectable>
inline const _<Object>& operator&&(const _<Object>& object, Connectable&& binding) {
   aui::tuple_visitor<typename AAnySignalOrPropertyTraits<std::decay_t<Connectable>>::args>::for_each_all([&]<typename... T>() {
     using Binding = ADataBindingDefault<std::decay_t<Object>, std::decay_t<T>...>;
     static_assert(requires {
         { Binding::property(object) } -> AAnyProperty;
     }, "ADataBindingDefault is required to have property() function to return any property; either define proper "
        "ADataBindingDefault specialization or explicitly specify the destination property.");
     static_assert(
         requires { { Binding::setup(object) }; },
         "ADataBindingDefault is required to have setup(const _<Object>&) function; either define proper "
         "ADataBindingDefault specialization or explicitly specify the destination property.");
     Binding::setup(object);
     AObject::biConnect(binding, Binding::property(object));
   });
   return object;
}
 
template <AAnyProperty Lhs, typename Destination>
struct Binding {
   Lhs sourceProperty;
   Destination destinationPointerToMember;
   explicit Binding(Lhs sourceProperty, Destination destinationPointerToMember)
     : sourceProperty(sourceProperty), destinationPointerToMember(destinationPointerToMember) {}
};
 
template <AAnyProperty Property, typename Destination>
inline decltype(auto) operator>(Property&& sourceProperty, Destination&& rhs) {
   return Binding<Property, Destination>(std::forward<Property>(sourceProperty), std::forward<Destination>(rhs));
}
 
template <typename Object, APropertyReadable Property, typename Destination>
inline const _<Object>& operator&(const _<Object>& object, Binding<Property, Destination>&& binding)
   requires requires {
       { binding.destinationPointerToMember } -> aui::invocable<Object&>;
       { std::invoke(binding.destinationPointerToMember, *object) } -> AAnyProperty;
   }
{
   AObject::connect(binding.sourceProperty, std::invoke(binding.destinationPointerToMember, *object));
   return object;
}
 
template <typename Object, APropertyWritable Property, typename Destination>
inline const _<Object>& operator&&(const _<Object>& object, Binding<Property, Destination>&& binding)
   requires requires {
       { binding.destinationPointerToMember } -> aui::invocable<Object&>;
       { std::invoke(binding.destinationPointerToMember, *object) } -> AAnyProperty;
   }
{
   AObject::biConnect(binding.sourceProperty, std::invoke(binding.destinationPointerToMember, *object));
   return object;
}
 
 
template <typename Object, APropertyReadable Property, typename Destination>
inline const _<Object>& operator&(const _<Object>& object, Binding<Property, Destination>&& binding)
   requires requires {
       { binding.destinationPointerToMember } -> aui::invocable<Object&, decltype(*binding.sourceProperty)>;
   }
{
   AObject::connect(
       binding.sourceProperty, object.get(),
       [object = object.get(), wrapped = std::move(binding.destinationPointerToMember)](
           const std::decay_t<decltype(*binding.sourceProperty)>& i) { std::invoke(wrapped, *object, i); });
   return object;
}
 
template <typename Object, APropertyWritable Property, typename Destination>
inline const _<Object>& operator&&(const _<Object>& object, Binding<Property, Destination>&& binding)
   requires requires {
       { binding.destinationPointerToMember } -> aui::invocable<Object&, decltype(*binding.sourceProperty)>;
   }
{
   AObject::biConnect(
       binding.sourceProperty, object.get(),
       [object = object.get(), wrapped = std::move(binding.destinationPointerToMember)](
           const std::decay_t<decltype(*binding.sourceProperty)>& i) { std::invoke(wrapped, *object, i); });
   return object;
}

© 2025 AUI Framework Contributors. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. All trademarks are property of their respective owners.