JUCE/modules/juce_gui_basics/native/accessibility/juce_win32_UIASelectionProvider.h

/*
  ==============================================================================

   This file is part of the JUCE 7 technical preview.
   Copyright (c) 2022 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For the technical preview this file cannot be licensed commercially.

   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
{

JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wlanguage-extension-token")

//==============================================================================
class UIASelectionItemProvider  : public UIAProviderBase,
                                  public ComBaseClassHelper<ComTypes::ISelectionItemProvider>
{
public:
    explicit UIASelectionItemProvider (AccessibilityNativeHandle* handle)
        : UIAProviderBase (handle),
          isRadioButton (getHandler().getRole() == AccessibilityRole::radioButton)
    {
    }

    //==============================================================================
    JUCE_COMRESULT AddToSelection() override
    {
        if (! isElementValid())
            return (HRESULT) UIA_E_ELEMENTNOTAVAILABLE;

        const auto& handler = getHandler();

        if (isRadioButton)
        {
            handler.getActions().invoke (AccessibilityActionType::press);
            sendAccessibilityAutomationEvent (handler, ComTypes::UIA_SelectionItem_ElementSelectedEventId);

            return S_OK;
        }

        handler.getActions().invoke (AccessibilityActionType::toggle);
        handler.getActions().invoke (AccessibilityActionType::press);

        return S_OK;
    }

    JUCE_COMRESULT get_IsSelected (BOOL* pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            const auto state = getHandler().getCurrentState();
            *pRetVal = isRadioButton ? state.isChecked() : state.isSelected();
            return S_OK;
        });
    }

    JUCE_COMRESULT get_SelectionContainer (IRawElementProviderSimple** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            if (! isRadioButton)
                if (auto* parent = getHandler().getParent())
                    parent->getNativeImplementation()->QueryInterface (IID_PPV_ARGS (pRetVal));

            return S_OK;
        });
    }

    JUCE_COMRESULT RemoveFromSelection() override
    {
        if (! isElementValid())
            return (HRESULT) UIA_E_ELEMENTNOTAVAILABLE;

        if (! isRadioButton)
        {
            const auto& handler = getHandler();

            if (handler.getCurrentState().isSelected())
                getHandler().getActions().invoke (AccessibilityActionType::toggle);
        }

        return S_OK;
    }

    JUCE_COMRESULT Select() override
    {
        if (! isElementValid())
            return (HRESULT) UIA_E_ELEMENTNOTAVAILABLE;

        AddToSelection();

        if (isElementValid() && ! isRadioButton)
        {
            const auto& handler = getHandler();

            if (auto* parent = handler.getParent())
                for (auto* child : parent->getChildren())
                    if (child != &handler && child->getCurrentState().isSelected())
                        child->getActions().invoke (AccessibilityActionType::toggle);
        }

        return S_OK;
    }

private:
    const bool isRadioButton;

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UIASelectionItemProvider)
};

//==============================================================================
class UIASelectionProvider  : public UIAProviderBase,
                              public ComBaseClassHelper<ComTypes::ISelectionProvider2>
{
public:
    using UIAProviderBase::UIAProviderBase;

    //==============================================================================
    JUCE_COMRESULT QueryInterface (REFIID iid, void** result) override
    {
        if (iid == __uuidof (IUnknown) || iid == __uuidof (ComTypes::ISelectionProvider))
            return castToType<ComTypes::ISelectionProvider> (result);

        if (iid == __uuidof (ComTypes::ISelectionProvider2))
            return castToType<ComTypes::ISelectionProvider2> (result);

        *result = nullptr;
        return E_NOINTERFACE;
    }

    //==============================================================================
    JUCE_COMRESULT get_CanSelectMultiple (BOOL* pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            *pRetVal = isMultiSelectable();
            return S_OK;
        });
    }

    JUCE_COMRESULT get_IsSelectionRequired (BOOL* pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            *pRetVal = getSelectedChildren().size() > 0 && ! isMultiSelectable();
            return S_OK;
        });
    }

    JUCE_COMRESULT GetSelection (SAFEARRAY** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            return addHandlersToArray (getSelectedChildren(), pRetVal);
        });
    }

    //==============================================================================
    JUCE_COMRESULT get_FirstSelectedItem (IRawElementProviderSimple** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            auto selectedChildren = getSelectedChildren();

            if (! selectedChildren.empty())
                selectedChildren.front()->getNativeImplementation()->QueryInterface (IID_PPV_ARGS (pRetVal));

            return S_OK;
        });
    }

    JUCE_COMRESULT get_LastSelectedItem (IRawElementProviderSimple** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            auto selectedChildren = getSelectedChildren();

            if (! selectedChildren.empty())
                selectedChildren.back()->getNativeImplementation()->QueryInterface (IID_PPV_ARGS (pRetVal));

            return S_OK;
        });
    }

    JUCE_COMRESULT get_CurrentSelectedItem (IRawElementProviderSimple** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            get_FirstSelectedItem (pRetVal);
            return S_OK;
        });
    }

    JUCE_COMRESULT get_ItemCount (int* pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            *pRetVal = (int) getSelectedChildren().size();
            return S_OK;
        });
    }

private:
    bool isMultiSelectable() const noexcept
    {
         return getHandler().getCurrentState().isMultiSelectable();
    }

    std::vector<const AccessibilityHandler*> getSelectedChildren() const
    {
        std::vector<const AccessibilityHandler*> selectedHandlers;

        for (auto* child : getHandler().getComponent().getChildren())
            if (auto* handler = child->getAccessibilityHandler())
                if (handler->getCurrentState().isSelected())
                    selectedHandlers.push_back (handler);

        return selectedHandlers;
    }

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UIASelectionProvider)
};

JUCE_END_IGNORE_WARNINGS_GCC_LIKE

} // namespace juce