juce_SelectedItemSet.h

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/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.
 
   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy
 
   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
template <class SelectableItemType>
class SelectedItemSet   : public ChangeBroadcaster
{
public:
    //==============================================================================
    using ItemType = SelectableItemType;
    using ItemArray = Array<SelectableItemType>;
    using ParameterType = typename TypeHelpers::ParameterType<SelectableItemType>::type;
 
    //==============================================================================
    SelectedItemSet() = default;

    explicit SelectedItemSet (const ItemArray& items)
        : selectedItems (items)
    {
    }

    SelectedItemSet (const SelectedItemSet& other)
        : ChangeBroadcaster(), selectedItems (other.selectedItems)
    {
    }

    SelectedItemSet& operator= (const SelectedItemSet& other)
    {
        if (selectedItems != other.selectedItems)
        {
            changed();
 
            for (int i = selectedItems.size(); --i >= 0;)
                if (! other.isSelected (selectedItems.getReference (i)))
                    itemDeselected (selectedItems.removeAndReturn (i));
 
            for (auto& i : other.selectedItems)
            {
                if (! isSelected (i))
                {
                    selectedItems.add (i);
                    itemSelected (i);
                }
            }
        }
 
        return *this;
    }
 
    //==============================================================================
    void selectOnly (ParameterType item)
    {
        if (isSelected (item))
        {
            for (int i = selectedItems.size(); --i >= 0;)
            {
                if (selectedItems.getUnchecked(i) != item)
                {
                    deselect (selectedItems.getUnchecked(i));
                    i = jmin (i, selectedItems.size());
                }
            }
        }
        else
        {
            changed();
            deselectAll();
 
            selectedItems.add (item);
            itemSelected (item);
        }
    }

    void addToSelection (ParameterType item)
    {
        if (! isSelected (item))
        {
            changed();
 
            selectedItems.add (item);
            itemSelected (item);
        }
    }

    void addToSelectionBasedOnModifiers (ParameterType item,
                                         ModifierKeys modifiers)
    {
        if (modifiers.isShiftDown())
        {
            addToSelection (item);
        }
        else if (modifiers.isCommandDown())
        {
            if (isSelected (item))
                deselect (item);
            else
                addToSelection (item);
        }
        else
        {
            selectOnly (item);
        }
    }

    bool addToSelectionOnMouseDown (ParameterType item,
                                    ModifierKeys modifiers)
    {
        if (isSelected (item))
            return ! modifiers.isPopupMenu();
 
        addToSelectionBasedOnModifiers (item, modifiers);
        return false;
    }

    void addToSelectionOnMouseUp (ParameterType item,
                                  ModifierKeys modifiers,
                                  const bool wasItemDragged,
                                  const bool resultOfMouseDownSelectMethod)
    {
        if (resultOfMouseDownSelectMethod && ! wasItemDragged)
            addToSelectionBasedOnModifiers (item, modifiers);
    }

    void deselect (ParameterType item)
    {
        const int i = selectedItems.indexOf (item);
 
        if (i >= 0)
        {
            changed();
            itemDeselected (selectedItems.removeAndReturn (i));
        }
    }

    void deselectAll()
    {
        if (selectedItems.size() > 0)
        {
            changed();
 
            for (int i = selectedItems.size(); --i >= 0;)
            {
                itemDeselected (selectedItems.removeAndReturn (i));
                i = jmin (i, selectedItems.size());
            }
        }
    }
 
    //==============================================================================
    int getNumSelected() const noexcept                         { return selectedItems.size(); }

    SelectableItemType getSelectedItem (const int index) const  { return selectedItems [index]; }

    bool isSelected (ParameterType item) const noexcept         { return selectedItems.contains (item); }

    const ItemArray& getItemArray() const noexcept              { return selectedItems; }

    SelectableItemType* begin() noexcept                        { return selectedItems.begin(); }
 
    const SelectableItemType* begin() const noexcept            { return selectedItems.begin(); }

    SelectableItemType* end() noexcept                          { return selectedItems.end(); }

    const SelectableItemType* end() const noexcept              { return selectedItems.end(); }
 
    //==============================================================================
    virtual void itemSelected (SelectableItemType)              {}

    virtual void itemDeselected (SelectableItemType)            {}

    void changed()
    {
        sendChangeMessage();
    }

    void changed (const bool synchronous)
    {
        if (synchronous)
            sendSynchronousChangeMessage();
        else
            sendChangeMessage();
    }
 
private:
    //==============================================================================
    ItemArray selectedItems;
 
    JUCE_LEAK_DETECTOR (SelectedItemSet<SelectableItemType>)
};
 
} // namespace juce