JUCE/modules/juce_gui_basics/native/accessibility/juce_win32_UIATextProvider.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
{

//==============================================================================
class UIATextProvider  : public UIAProviderBase,
                         public ComBaseClassHelper<ComTypes::ITextProvider2>
{
public:
    using UIAProviderBase::UIAProviderBase;

    //==============================================================================
    JUCE_COMRESULT QueryInterface (REFIID iid, void** result) override
    {
        JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wlanguage-extension-token")

        if (iid == __uuidof (IUnknown) || iid == __uuidof (ComTypes::ITextProvider))
            return castToType<ComTypes::ITextProvider> (result);

        if (iid == __uuidof (ComTypes::ITextProvider2))
            return castToType<ComTypes::ITextProvider2> (result);

        *result = nullptr;
        return E_NOINTERFACE;

        JUCE_END_IGNORE_WARNINGS_GCC_LIKE
    }

    //=============================================================================
    JUCE_COMRESULT get_DocumentRange (ComTypes::ITextRangeProvider** pRetVal) override
    {
        return withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
        {
            *pRetVal = new UIATextRangeProvider (*this, { 0, textInterface.getTotalNumCharacters() });
            return S_OK;
        });
    }

    JUCE_COMRESULT get_SupportedTextSelection (ComTypes::SupportedTextSelection* pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, [&]
        {
            *pRetVal = ComTypes::SupportedTextSelection_Single;
            return S_OK;
        });
    }

    JUCE_COMRESULT GetSelection (SAFEARRAY** pRetVal) override
    {
        return withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
        {
            *pRetVal = SafeArrayCreateVector (VT_UNKNOWN, 0, 1);

            if (pRetVal != nullptr)
            {
                auto selection = textInterface.getSelection();
                auto hasSelection = ! selection.isEmpty();
                auto cursorPos = textInterface.getTextInsertionOffset();

                auto* rangeProvider = new UIATextRangeProvider (*this,
                                                                { hasSelection ? selection.getStart() : cursorPos,
                                                                  hasSelection ? selection.getEnd()   : cursorPos });

                LONG pos = 0;
                auto hr = SafeArrayPutElement (*pRetVal, &pos, static_cast<IUnknown*> (rangeProvider));

                if (FAILED (hr))
                    return E_FAIL;

                rangeProvider->Release();
            }

            return S_OK;
        });
    }

    JUCE_COMRESULT GetVisibleRanges (SAFEARRAY** pRetVal) override
    {
        return withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
        {
            *pRetVal = SafeArrayCreateVector (VT_UNKNOWN, 0, 1);

            if (pRetVal != nullptr)
            {
                auto* rangeProvider = new UIATextRangeProvider (*this, { 0, textInterface.getTotalNumCharacters() });

                LONG pos = 0;
                auto hr = SafeArrayPutElement (*pRetVal, &pos, static_cast<IUnknown*> (rangeProvider));

                if (FAILED (hr))
                    return E_FAIL;

                rangeProvider->Release();
            }

            return S_OK;
        });
    }

    JUCE_COMRESULT RangeFromChild (IRawElementProviderSimple*, ComTypes::ITextRangeProvider** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, []
        {
            return S_OK;
        });
    }

    JUCE_COMRESULT RangeFromPoint (ComTypes::UiaPoint point, ComTypes::ITextRangeProvider** pRetVal) override
    {
        return withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
        {
            auto offset = textInterface.getOffsetAtPoint ({ roundToInt (point.x), roundToInt (point.y) });

            if (offset > 0)
                *pRetVal = new UIATextRangeProvider (*this, { offset, offset });

            return S_OK;
        });
    }

    //==============================================================================
    JUCE_COMRESULT GetCaretRange (BOOL* isActive, ComTypes::ITextRangeProvider** pRetVal) override
    {
        return withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
        {
            *isActive = getHandler().hasFocus (false);

            auto cursorPos = textInterface.getTextInsertionOffset();
            *pRetVal = new UIATextRangeProvider (*this, { cursorPos, cursorPos });

            return S_OK;
        });
    }

    JUCE_COMRESULT RangeFromAnnotation (IRawElementProviderSimple*, ComTypes::ITextRangeProvider** pRetVal) override
    {
        return withCheckedComArgs (pRetVal, *this, []
        {
            return S_OK;
        });
    }

private:
    //==============================================================================
    template <typename Value, typename Callback>
    JUCE_COMRESULT withTextInterface (Value* pRetVal, Callback&& callback) const
    {
        return withCheckedComArgs (pRetVal, *this, [&]() -> HRESULT
        {
            if (auto* textInterface = getHandler().getTextInterface())
                return callback (*textInterface);

            return (HRESULT) UIA_E_NOTSUPPORTED;
        });
    }

    //==============================================================================
    class UIATextRangeProvider  : public UIAProviderBase,
                                  public ComBaseClassHelper<ComTypes::ITextRangeProvider>
    {
    public:
        UIATextRangeProvider (UIATextProvider& textProvider, Range<int> range)
            : UIAProviderBase (textProvider.getHandler().getNativeImplementation()),
              owner (&textProvider),
              selectionRange (range)
        {
        }

        //==============================================================================
        Range<int> getSelectionRange() const noexcept  { return selectionRange; }

        //==============================================================================
        JUCE_COMRESULT AddToSelection() override
        {
            return Select();
        }

        JUCE_COMRESULT Clone (ComTypes::ITextRangeProvider** pRetVal) override
        {
            return withCheckedComArgs (pRetVal, *this, [&]
            {
                *pRetVal = new UIATextRangeProvider (*owner, selectionRange);
                return S_OK;
            });
        }

        JUCE_COMRESULT Compare (ComTypes::ITextRangeProvider* range, BOOL* pRetVal) override
        {
            return withCheckedComArgs (pRetVal, *this, [&]
            {
                *pRetVal = (selectionRange == static_cast<UIATextRangeProvider*> (range)->getSelectionRange());
                return S_OK;
            });
        }

        JUCE_COMRESULT CompareEndpoints (ComTypes::TextPatternRangeEndpoint endpoint,
                                         ComTypes::ITextRangeProvider* targetRange,
                                         ComTypes::TextPatternRangeEndpoint targetEndpoint,
                                         int* pRetVal) override
        {
            if (targetRange == nullptr)
                return E_INVALIDARG;

            return withCheckedComArgs (pRetVal, *this, [&]
            {
                auto offset = (endpoint == ComTypes::TextPatternRangeEndpoint_Start ? selectionRange.getStart()
                                                                                    : selectionRange.getEnd());

                auto otherRange = static_cast<UIATextRangeProvider*> (targetRange)->getSelectionRange();
                auto otherOffset = (targetEndpoint == ComTypes::TextPatternRangeEndpoint_Start ? otherRange.getStart()
                                                                                               : otherRange.getEnd());

                *pRetVal = offset - otherOffset;
                return S_OK;
            });
        }

        JUCE_COMRESULT ExpandToEnclosingUnit (ComTypes::TextUnit unit) override
        {
            if (! isElementValid())
                return (HRESULT) UIA_E_ELEMENTNOTAVAILABLE;

            if (auto* textInterface = owner->getHandler().getTextInterface())
            {
                const auto boundaryType = getBoundaryType (unit);

                const auto start = unit == ComTypes::TextUnit::TextUnit_Character
                                 ? selectionRange.getStart()
                                 : AccessibilityTextHelpers::findTextBoundary (*textInterface,
                                                                               selectionRange.getStart(),
                                                                               boundaryType,
                                                                               AccessibilityTextHelpers::Direction::backwards);

                const auto end = AccessibilityTextHelpers::findTextBoundary (*textInterface,
                                                                             start,
                                                                             boundaryType,
                                                                             AccessibilityTextHelpers::Direction::forwards);

                selectionRange = Range<int> (start, end);

                return S_OK;
            }

            return (HRESULT) UIA_E_NOTSUPPORTED;
        }

        JUCE_COMRESULT FindAttribute (TEXTATTRIBUTEID, VARIANT, BOOL, ComTypes::ITextRangeProvider** pRetVal) override
        {
            return withCheckedComArgs (pRetVal, *this, []
            {
                return S_OK;
            });
        }

        JUCE_COMRESULT FindText (BSTR text, BOOL backward, BOOL ignoreCase,
                                 ComTypes::ITextRangeProvider** pRetVal) override
        {
            return owner->withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
            {
                auto selectionText = textInterface.getText (selectionRange);
                String textToSearchFor (text);

                auto offset = (backward ? (ignoreCase ? selectionText.lastIndexOfIgnoreCase (textToSearchFor) : selectionText.lastIndexOf (textToSearchFor))
                                        : (ignoreCase ? selectionText.indexOfIgnoreCase (textToSearchFor)     : selectionText.indexOf (textToSearchFor)));

                if (offset != -1)
                    *pRetVal = new UIATextRangeProvider (*owner, { offset, offset + textToSearchFor.length() });

                return S_OK;
            });
        }

        JUCE_COMRESULT GetAttributeValue (TEXTATTRIBUTEID attributeId, VARIANT* pRetVal) override
        {
            return owner->withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
            {
                VariantHelpers::clear (pRetVal);

                switch (attributeId)
                {
                    case ComTypes::UIA_IsReadOnlyAttributeId:
                    {
                        VariantHelpers::setBool (textInterface.isReadOnly(), pRetVal);
                        break;
                    }

                    case ComTypes::UIA_CaretPositionAttributeId:
                    {
                        auto cursorPos = textInterface.getTextInsertionOffset();

                        auto caretPos = [&]
                        {
                            if (cursorPos == 0)
                                return ComTypes::CaretPosition_BeginningOfLine;

                            if (cursorPos == textInterface.getTotalNumCharacters())
                                return ComTypes::CaretPosition_EndOfLine;

                            return ComTypes::CaretPosition_Unknown;
                        }();

                        VariantHelpers::setInt (caretPos, pRetVal);
                        break;
                    }
                }

                return S_OK;
            });
        }

        JUCE_COMRESULT GetBoundingRectangles (SAFEARRAY** pRetVal) override
        {
            return owner->withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
            {
                auto rectangleList = textInterface.getTextBounds (selectionRange);
                auto numRectangles = rectangleList.getNumRectangles();

                *pRetVal = SafeArrayCreateVector (VT_R8, 0, 4 * (ULONG) numRectangles);

                if (*pRetVal == nullptr)
                    return E_FAIL;

                if (numRectangles > 0)
                {
                    double* doubleArr = nullptr;

                    if (FAILED (SafeArrayAccessData (*pRetVal, reinterpret_cast<void**> (&doubleArr))))
                    {
                        SafeArrayDestroy (*pRetVal);
                        return E_FAIL;
                    }

                    for (int i = 0; i < numRectangles; ++i)
                    {
                        auto r = Desktop::getInstance().getDisplays().logicalToPhysical (rectangleList.getRectangle (i));

                        doubleArr[i * 4]     = r.getX();
                        doubleArr[i * 4 + 1] = r.getY();
                        doubleArr[i * 4 + 2] = r.getWidth();
                        doubleArr[i * 4 + 3] = r.getHeight();
                    }

                    if (FAILED (SafeArrayUnaccessData (*pRetVal)))
                    {
                        SafeArrayDestroy (*pRetVal);
                        return E_FAIL;
                    }
                }

                return S_OK;
            });
        }

        JUCE_COMRESULT GetChildren (SAFEARRAY** pRetVal) override
        {
            return withCheckedComArgs (pRetVal, *this, [&]
            {
                *pRetVal = SafeArrayCreateVector (VT_UNKNOWN, 0, 0);
                return S_OK;
            });
        }

        JUCE_COMRESULT GetEnclosingElement (IRawElementProviderSimple** pRetVal) override
        {
            JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wlanguage-extension-token")

            return withCheckedComArgs (pRetVal, *this, [&]
            {
                getHandler().getNativeImplementation()->QueryInterface (IID_PPV_ARGS (pRetVal));
                return S_OK;
            });

            JUCE_END_IGNORE_WARNINGS_GCC_LIKE
        }

        JUCE_COMRESULT GetText (int maxLength, BSTR* pRetVal) override
        {
            return owner->withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
            {
                auto text = textInterface.getText (selectionRange);

                if (maxLength >= 0 && text.length() > maxLength)
                    text = text.substring (0, maxLength);

                *pRetVal = SysAllocString ((const OLECHAR*) text.toWideCharPointer());
                return S_OK;
            });
        }

        JUCE_COMRESULT Move (ComTypes::TextUnit unit, int count, int* pRetVal) override
        {
            return owner->withTextInterface (pRetVal, [&] (const AccessibilityTextInterface&)
            {
                if (count > 0)
                {
                    MoveEndpointByUnit (ComTypes::TextPatternRangeEndpoint_End, unit, count, pRetVal);
                    MoveEndpointByUnit (ComTypes::TextPatternRangeEndpoint_Start, unit, count, pRetVal);
                }
                else if (count < 0)
                {
                    MoveEndpointByUnit (ComTypes::TextPatternRangeEndpoint_Start, unit, count, pRetVal);
                    MoveEndpointByUnit (ComTypes::TextPatternRangeEndpoint_End, unit, count, pRetVal);
                }

                return S_OK;
            });
        }

        JUCE_COMRESULT MoveEndpointByRange (ComTypes::TextPatternRangeEndpoint endpoint,
                                            ComTypes::ITextRangeProvider* targetRange,
                                            ComTypes::TextPatternRangeEndpoint targetEndpoint) override
        {
            if (targetRange == nullptr)
                return E_INVALIDARG;

            if (! isElementValid())
                return (HRESULT) UIA_E_ELEMENTNOTAVAILABLE;

            if (owner->getHandler().getTextInterface() != nullptr)
            {
                auto otherRange = static_cast<UIATextRangeProvider*> (targetRange)->getSelectionRange();
                auto targetPoint = (targetEndpoint == ComTypes::TextPatternRangeEndpoint_Start ? otherRange.getStart()
                                                                                               : otherRange.getEnd());

                setEndpointChecked (endpoint, targetPoint);
                return S_OK;
            }

            return (HRESULT) UIA_E_NOTSUPPORTED;
        }

        JUCE_COMRESULT MoveEndpointByUnit (ComTypes::TextPatternRangeEndpoint endpoint,
                                           ComTypes::TextUnit unit,
                                           int count,
                                           int* pRetVal) override
        {
            return owner->withTextInterface (pRetVal, [&] (const AccessibilityTextInterface& textInterface)
            {
                if (count == 0 || textInterface.getTotalNumCharacters() == 0)
                    return S_OK;

                auto endpointToMove = (endpoint == ComTypes::TextPatternRangeEndpoint_Start ? selectionRange.getStart()
                                                                                            : selectionRange.getEnd());

                const auto direction = (count > 0 ? AccessibilityTextHelpers::Direction::forwards
                                                  : AccessibilityTextHelpers::Direction::backwards);

                const auto boundaryType = getBoundaryType (unit);

                // handle case where endpoint is on a boundary
                if (AccessibilityTextHelpers::findTextBoundary (textInterface, endpointToMove, boundaryType, direction) == endpointToMove)
                    endpointToMove += (direction == AccessibilityTextHelpers::Direction::forwards ? 1 : -1);

                int numMoved;
                for (numMoved = 0; numMoved < std::abs (count); ++numMoved)
                {
                    auto nextEndpoint = AccessibilityTextHelpers::findTextBoundary (textInterface,
                                                                                    endpointToMove,
                                                                                    boundaryType,
                                                                                    direction);

                    if (nextEndpoint == endpointToMove)
                        break;

                    endpointToMove = nextEndpoint;
                }

                *pRetVal = numMoved;
                setEndpointChecked (endpoint, endpointToMove);

                return S_OK;
            });
        }

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

            if (auto* textInterface = owner->getHandler().getTextInterface())
            {
                textInterface->setSelection ({});
                return S_OK;
            }

            return (HRESULT) UIA_E_NOTSUPPORTED;
        }

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

            return (HRESULT) UIA_E_NOTSUPPORTED;
        }

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

            if (auto* textInterface = owner->getHandler().getTextInterface())
            {
                textInterface->setSelection ({});
                textInterface->setSelection (selectionRange);

                return S_OK;
            }

            return (HRESULT) UIA_E_NOTSUPPORTED;
        }

    private:
        static AccessibilityTextHelpers::BoundaryType getBoundaryType (ComTypes::TextUnit unit)
        {
            switch (unit)
            {
                case ComTypes::TextUnit_Character:
                    return AccessibilityTextHelpers::BoundaryType::character;

                case ComTypes::TextUnit_Format:
                case ComTypes::TextUnit_Word:
                    return AccessibilityTextHelpers::BoundaryType::word;

                case ComTypes::TextUnit_Line:
                    return AccessibilityTextHelpers::BoundaryType::line;

                case ComTypes::TextUnit_Paragraph:
                case ComTypes::TextUnit_Page:
                case ComTypes::TextUnit_Document:
                    return AccessibilityTextHelpers::BoundaryType::document;
            };

            jassertfalse;
            return AccessibilityTextHelpers::BoundaryType::character;
        }

        void setEndpointChecked (ComTypes::TextPatternRangeEndpoint endpoint, int newEndpoint)
        {
            if (endpoint == ComTypes::TextPatternRangeEndpoint_Start)
            {
                if (selectionRange.getEnd() < newEndpoint)
                    selectionRange.setEnd (newEndpoint);

                selectionRange.setStart (newEndpoint);
            }
            else
            {
                if (selectionRange.getStart() > newEndpoint)
                    selectionRange.setStart (newEndpoint);

                selectionRange.setEnd (newEndpoint);
            }
        }

        ComSmartPtr<UIATextProvider> owner;
        Range<int> selectionRange;

        //==============================================================================
        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UIATextRangeProvider)
    };

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UIATextProvider)
};

} // namespace juce