JUCE/modules/juce_gui_basics/native/accessibility/juce_win32_UIAGridItemProvider.h

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

   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
{

//==============================================================================
class UIAGridItemProvider  : public UIAProviderBase,
                             public ComBaseClassHelper<ComTypes::IGridItemProvider, ComTypes::ITableItemProvider>
{
public:
    using UIAProviderBase::UIAProviderBase;

    //==============================================================================
    JUCE_COMRESULT get_Row (int* pRetVal) override
    {
        return withTableSpan (pRetVal,
                              &AccessibilityTableInterface::getRowSpan,
                              &AccessibilityTableInterface::Span::begin);
    }

    JUCE_COMRESULT get_Column (int* pRetVal) override
    {
        return withTableSpan (pRetVal,
                              &AccessibilityTableInterface::getColumnSpan,
                              &AccessibilityTableInterface::Span::begin);
    }

    JUCE_COMRESULT get_RowSpan (int* pRetVal) override
    {
        return withTableSpan (pRetVal,
                              &AccessibilityTableInterface::getRowSpan,
                              &AccessibilityTableInterface::Span::num);
    }

    JUCE_COMRESULT get_ColumnSpan (int* pRetVal) override
    {
        return withTableSpan (pRetVal,
                              &AccessibilityTableInterface::getColumnSpan,
                              &AccessibilityTableInterface::Span::num);
    }

    JUCE_COMRESULT get_ContainingGrid (IRawElementProviderSimple** pRetVal) override
    {
        return withTableInterface (pRetVal, [&] (const AccessibilityHandler& tableHandler)
        {
            JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wlanguage-extension-token")
            tableHandler.getNativeImplementation()->QueryInterface (IID_PPV_ARGS (pRetVal));
            JUCE_END_IGNORE_WARNINGS_GCC_LIKE

            return true;
        });
    }

    JUCE_COMRESULT GetRowHeaderItems (SAFEARRAY**) override
    {
        return (HRESULT) UIA_E_NOTSUPPORTED;
    }

    JUCE_COMRESULT GetColumnHeaderItems (SAFEARRAY** pRetVal) override
    {
        return withTableInterface (pRetVal, [&] (const AccessibilityHandler& tableHandler)
        {
            if (auto* tableInterface = tableHandler.getTableInterface())
            {
                if (const auto column = tableInterface->getColumnSpan (getHandler()))
                {
                    if (auto* header = tableInterface->getHeaderHandler())
                    {
                        const auto children = header->getChildren();

                        if (isPositiveAndBelow (column->begin, children.size()))
                        {
                            IRawElementProviderSimple* provider = nullptr;

                            if (auto* child = children[(size_t) column->begin])
                            {
                                JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wlanguage-extension-token")
                                if (child->getNativeImplementation()->QueryInterface (IID_PPV_ARGS (&provider)) == S_OK && provider != nullptr)
                                {
                                    *pRetVal = SafeArrayCreateVector (VT_UNKNOWN, 0, 1);
                                    LONG index = 0;
                                    const auto hr = SafeArrayPutElement (*pRetVal, &index, provider);

                                    return ! FAILED (hr);
                                }
                                JUCE_END_IGNORE_WARNINGS_GCC_LIKE
                            }
                        }
                    }
                }
            }

            return false;
        });
    }
private:
    template <typename Value, typename Callback>
    JUCE_COMRESULT withTableInterface (Value* pRetVal, Callback&& callback) const
    {
        return withCheckedComArgs (pRetVal, *this, [&]() -> HRESULT
        {
            if (auto* handler = getEnclosingHandlerWithInterface (&getHandler(), &AccessibilityHandler::getTableInterface))
                if (handler->getTableInterface() != nullptr && callback (*handler))
                    return S_OK;

            return (HRESULT) UIA_E_NOTSUPPORTED;
        });
    }

    JUCE_COMRESULT withTableSpan (int* pRetVal,
                                  Optional<AccessibilityTableInterface::Span> (AccessibilityTableInterface::* getSpan) (const AccessibilityHandler&) const,
                                  int AccessibilityTableInterface::Span::* spanMember) const
    {
        return withTableInterface (pRetVal, [&] (const AccessibilityHandler& handler)
        {
            if (const auto span = ((handler.getTableInterface())->*getSpan) (getHandler()))
            {
                *pRetVal = (*span).*spanMember;
                return true;
            }

            return false;
        });
    }

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UIAGridItemProvider)
};

} // namespace juce