AListModelFilter.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/Model/IListModel.h>
#include <AUI/Model/IMutableListModel.h>
#include <AUI/Common/AVector.h>
 
template<typename T, typename Filter>
class AListModelFilter: public IListModel<T> {
private:
   _<IListModel<T>> mOther;
   Filter mFilter;
   AVector<size_t> mMapping;
 
   void fill() {
       for (size_t i = 0; i < mOther->listSize(); ++i) {
           if (mFilter(mOther->listItemAt(i))) {
               mMapping.push_back(i);
           }
       }
   }
public:
   using value_type = T;
 
   explicit AListModelFilter(const _<IListModel<T>>& other, Filter&& adapter) :
           mOther(other),
           mFilter(std::forward<Filter>(adapter)) {
       fill();
 
       AObject::connect(other->dataChanged, this, [&](const AListModelRange<T>& r){
           AUI_ASSERTX(0, "unimplemented");
       });
       AObject::connect(other->dataInserted, this, [&](const AListModelRange<T>& r){
           AUI_ASSERTX(0, "unimplemented");
       });
       AObject::connect(other->dataRemoved, this, [&](const AListModelRange<T>& r){
           AUI_ASSERTX(0, "unimplemented");
       });
   }
 
 
   ~AListModelFilter() override = default;
 
   size_t listSize() override {
       return mMapping.size();
   }
 
   T listItemAt(const AListModelIndex& index) override {
       return mOther->listItemAt(mMapping[index.getRow()]);
   }

   void invalidate() {
       size_t prevSize = mMapping.size();
       mMapping.clear();
       fill();
 
       size_t currentSize = mMapping.size();
       if (currentSize == prevSize) {
           emit this->dataChanged(this->range(0, currentSize));
       } else if (currentSize > prevSize) {
           emit this->dataChanged(this->range(0, prevSize));
           emit this->dataInserted(this->range(prevSize, currentSize));
       } else {
           emit this->dataChanged(this->range(0, currentSize));
           emit this->dataRemoved(this->range(currentSize, prevSize));
       }
   }

   void lazyInvalidate() {
       auto ranges = this->rangesIncluding([&](size_t i) {
           return !mFilter(listItemAt(i));
       });
       int offset = 0;
       for (const AListModelRange<T>& r : ranges) {
           mMapping.erase(mMapping.begin() + r.getBegin().getRow() - offset, mMapping.begin() + r.getEnd().getRow()) - offset;
           offset += r.getEnd().getRow() - r.getBegin().getRow();
       }
   }
};
 
namespace AModels {
   template <typename Container, typename Filter>
   auto filter(const _<Container>& other, Filter&& filter) -> _<AListModelFilter<typename Container::value_type, Filter>> {
       return aui::ptr::manage(new AListModelFilter<typename Container::value_type, Filter>(other, std::forward<Filter>(filter)));
   }
}
 

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