visibleselection.cpp

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            VisiblePosition end = endOfLine(VisiblePosition(m_end, m_affinity));
            // If the end of this line is at the end of a paragraph, include the space 
            // after the end of the line in the selection.
            if (isEndOfParagraph(end)) {
                VisiblePosition next = end.next();
                if (next.isNotNull())
                    end = next;
            }
            m_end = end.deepEquivalent();
            break;
        }
        case LineBoundary:
            m_start = startOfLine(VisiblePosition(m_start, m_affinity)).deepEquivalent();
            m_end = endOfLine(VisiblePosition(m_end, m_affinity)).deepEquivalent();
            break;
        case ParagraphGranularity: {
            VisiblePosition pos(m_start, m_affinity);
            if (isStartOfLine(pos) && isEndOfDocument(pos))
                pos = pos.previous();
            m_start = startOfParagraph(pos).deepEquivalent();
            VisiblePosition visibleParagraphEnd = endOfParagraph(VisiblePosition(m_end, m_affinity));
            
            // Include the "paragraph break" (the space from the end of this paragraph to the start
            // of the next one) in the selection.
            VisiblePosition end(visibleParagraphEnd.next());
             
            if (Node* table = isFirstPositionAfterTable(end)) {
                // The paragraph break after the last paragraph in the last cell of a block table ends
                // at the start of the paragraph after the table, not at the position just after the table.
                if (isBlock(table))
                    end = end.next(true);
                // There is no parargraph break after the last paragraph in the last cell of an inline table.
                else
                    end = visibleParagraphEnd;
            }
             
            if (end.isNull())
                end = visibleParagraphEnd;
                
            m_end = end.deepEquivalent();
            break;
        }
        case DocumentBoundary:
            m_start = startOfDocument(VisiblePosition(m_start, m_affinity)).deepEquivalent();
            m_end = endOfDocument(VisiblePosition(m_end, m_affinity)).deepEquivalent();
            break;
        case ParagraphBoundary:
            m_start = startOfParagraph(VisiblePosition(m_start, m_affinity)).deepEquivalent();
            m_end = endOfParagraph(VisiblePosition(m_end, m_affinity)).deepEquivalent();
            break;
        case SentenceBoundary:
            m_start = startOfSentence(VisiblePosition(m_start, m_affinity)).deepEquivalent();
            m_end = endOfSentence(VisiblePosition(m_end, m_affinity)).deepEquivalent();
            break;
    }
    
    // Make sure we do not have a dangling start or end.
    if (m_start.isNull())
        m_start = m_end;
    if (m_end.isNull())
        m_end = m_start;
}

void VisibleSelection::updateSelectionType()
{
    if (m_start.isNull()) {
        ASSERT(m_end.isNull());
        m_selectionType = NoSelection;
    } else if (m_start == m_end || m_start.upstream() == m_end.upstream()) {
        m_selectionType = CaretSelection;
    } else
        m_selectionType = RangeSelection;

    // Affinity only makes sense for a caret
    if (m_selectionType != CaretSelection)
        m_affinity = DOWNSTREAM;
}

void VisibleSelection::validate()
{
    setBaseAndExtentToDeepEquivalents();
    setStartAndEndFromBaseAndExtentRespectingGranularity();
    adjustSelectionToAvoidCrossingEditingBoundaries();
    updateSelectionType();

    if (selectionType() == RangeSelection) {
        // "Constrain" the selection to be the smallest equivalent range of nodes.
        // This is a somewhat arbitrary choice, but experience shows that it is
        // useful to make to make the selection "canonical" (if only for
        // purposes of comparing selections). This is an ideal point of the code
        // to do this operation, since all selection changes that result in a RANGE 
        // come through here before anyone uses it.
        // FIXME: Canonicalizing is good, but haven't we already done it (when we
        // set these two positions to VisiblePosition deepEquivalent()s above)?
        m_start = m_start.downstream();
        m_end = m_end.upstream();
    }
}

// FIXME: This function breaks the invariant of this class.
// But because we use VisibleSelection to store values in editing commands for use when
// undoing the command, we need to be able to create a selection that while currently
// invalid, will be valid once the changes are undone. This is a design problem.
// To fix it we either need to change the invariants of VisibleSelection or create a new
// class for editing to use that can manipulate selections that are not currently valid.
void VisibleSelection::setWithoutValidation(const Position& base, const Position& extent)
{
    ASSERT(!base.isNull());
    ASSERT(!extent.isNull());
    ASSERT(base != extent);
    ASSERT(m_affinity == DOWNSTREAM);
    ASSERT(m_granularity == CharacterGranularity);
    m_base = base;
    m_extent = extent;
    m_baseIsFirst = comparePositions(base, extent) <= 0;
    if (m_baseIsFirst) {
        m_start = base;
        m_end = extent;
    } else {
        m_start = extent;
        m_end = base;
    }
    m_selectionType = RangeSelection;
}

void VisibleSelection::adjustSelectionToAvoidCrossingEditingBoundaries()
{
    if (m_base.isNull() || m_start.isNull() || m_end.isNull())
        return;

    Node* baseRoot = highestEditableRoot(m_base);
    Node* startRoot = highestEditableRoot(m_start);
    Node* endRoot = highestEditableRoot(m_end);
    
    Node* baseEditableAncestor = lowestEditableAncestor(m_base.node());
    
    // The base, start and end are all in the same region.  No adjustment necessary.
    if (baseRoot == startRoot && baseRoot == endRoot)
        return;
    
    // The selection is based in editable content.
    if (baseRoot) {
        // If the start is outside the base's editable root, cap it at the start of that root.
        // If the start is in non-editable content that is inside the base's editable root, put it
        // at the first editable position after start inside the base's editable root.
        if (startRoot != baseRoot) {
            VisiblePosition first = firstEditablePositionAfterPositionInRoot(m_start, baseRoot);
            m_start = first.deepEquivalent();
            if (m_start.isNull()) {
                ASSERT_NOT_REACHED();
                m_start = m_end;
            }
        }
        // If the end is outside the base's editable root, cap it at the end of that root.
        // If the end is in non-editable content that is inside the base's root, put it
        // at the last editable position before the end inside the base's root.
        if (endRoot != baseRoot) {
            VisiblePosition last = lastEditablePositionBeforePositionInRoot(m_end, baseRoot);
            m_end = last.deepEquivalent();
            if (m_end.isNull()) {
                ASSERT_NOT_REACHED();
                m_end = m_start;
            }
        }
    // The selection is based in non-editable content.
    } else {
        // FIXME: Non-editable pieces inside editable content should be atomic, in the same way that editable
        // pieces in non-editable content are atomic.
    
        // The selection ends in editable content or non-editable content inside a different editable ancestor, 
        // move backward until non-editable content inside the same lowest editable ancestor is reached.
        Node* endEditableAncestor = lowestEditableAncestor(m_end.node());
        if (endRoot || endEditableAncestor != baseEditableAncestor) {
            
            Position p = previousVisuallyDistinctCandidate(m_end);
            Node* shadowAncestor = endRoot ? endRoot->shadowAncestorNode() : 0;
            if (p.isNull() && endRoot && (shadowAncestor != endRoot))
                p = Position(shadowAncestor, maxDeepOffset(shadowAncestor));
            while (p.isNotNull() && !(lowestEditableAncestor(p.node()) == baseEditableAncestor && !isEditablePosition(p))) {
                Node* root = editableRootForPosition(p);
                shadowAncestor = root ? root->shadowAncestorNode() : 0;
                p = isAtomicNode(p.node()) ? positionBeforeNode(p.node()) : previousVisuallyDistinctCandidate(p);
                if (p.isNull() && (shadowAncestor != root))
                    p = Position(shadowAncestor, maxDeepOffset(shadowAncestor));
            }
            VisiblePosition previous(p);

            if (previous.isNull()) {
                // The selection crosses an Editing boundary.  This is a
                // programmer error in the editing code.  Happy debugging!
                ASSERT_NOT_REACHED();
                m_base = Position();
                m_extent = Position();
                validate();
                return;
            }
            m_end = previous.deepEquivalent();
        }

        // The selection starts in editable content or non-editable content inside a different editable ancestor, 
        // move forward until non-editable content inside the same lowest editable ancestor is reached.
        Node* startEditableAncestor = lowestEditableAncestor(m_start.node());      
        if (startRoot || startEditableAncestor != baseEditableAncestor) {
            Position p = nextVisuallyDistinctCandidate(m_start);
            Node* shadowAncestor = startRoot ? startRoot->shadowAncestorNode() : 0;
            if (p.isNull() && startRoot && (shadowAncestor != startRoot))
                p = Position(shadowAncestor, 0);
            while (p.isNotNull() && !(lowestEditableAncestor(p.node()) == baseEditableAncestor && !isEditablePosition(p))) {
                Node* root = editableRootForPosition(p);
                shadowAncestor = root ? root->shadowAncestorNode() : 0;
                p = isAtomicNode(p.node()) ? positionAfterNode(p.node()) : nextVisuallyDistinctCandidate(p);
                if (p.isNull() && (shadowAncestor != root))
                    p = Position(shadowAncestor, 0);
            }
            VisiblePosition next(p);
            
            if (next.isNull()) {
                // The selection crosses an Editing boundary.  This is a
                // programmer error in the editing code.  Happy debugging!
                ASSERT_NOT_REACHED();
                m_base = Position();
                m_extent = Position();
                validate();
                return;
            }
            m_start = next.deepEquivalent();
        }
    }
    
    // Correct the extent if necessary.
    if (baseEditableAncestor != lowestEditableAncestor(m_extent.node()))
        m_extent = m_baseIsFirst ? m_end : m_start;
}

bool VisibleSelection::isContentEditable() const
{
    return isEditablePosition(start());
}

bool VisibleSelection::isContentRichlyEditable() const
{
    return isRichlyEditablePosition(start());
}

Element* VisibleSelection::rootEditableElement() const
{
    return editableRootForPosition(start());
}

Node* VisibleSelection::shadowTreeRootNode() const
{
    return start().node() ? start().node()->shadowTreeRootNode() : 0;
}

void VisibleSelection::debugPosition() const
{
    if (!m_start.node())
        return;

    fprintf(stderr, "VisibleSelection =================\n");

    if (m_start == m_end) {
        Position pos = m_start;
        fprintf(stderr, "pos:        %s %p:%d\n", pos.node()->nodeName().utf8().data(), pos.node(), pos.offset());
    } else {
        Position pos = m_start;
        fprintf(stderr, "start:      %s %p:%d\n", pos.node()->nodeName().utf8().data(), pos.node(), pos.offset());
        fprintf(stderr, "-----------------------------------\n");
        pos = m_end;
        fprintf(stderr, "end:        %s %p:%d\n", pos.node()->nodeName().utf8().data(), pos.node(), pos.offset());
        fprintf(stderr, "-----------------------------------\n");
    }

    fprintf(stderr, "================================\n");
}

#ifndef NDEBUG

void VisibleSelection::formatForDebugger(char* buffer, unsigned length) const
{
    String result;
    String s;
    
    if (isNone()) {
        result = "<none>";
    } else {
        const int FormatBufferSize = 1024;
        char s[FormatBufferSize];
        result += "from ";
        start().formatForDebugger(s, FormatBufferSize);
        result += s;
        result += " to ";
        end().formatForDebugger(s, FormatBufferSize);
        result += s;
    }

    strncpy(buffer, result.utf8().data(), length - 1);
}

void VisibleSelection::showTreeForThis() const
{
    if (start().node()) {
        start().node()->showTreeAndMark(start().node(), "S", end().node(), "E");
        fprintf(stderr, "start offset: %d, end offset: %d\n", start().offset(), end().offset());
    }
}

#endif

} // namespace WebCore

#ifndef NDEBUG

void showTree(const WebCore::VisibleSelection& sel)
{
    sel.showTreeForThis();
}

void showTree(const WebCore::VisibleSelection* sel)
{
    if (sel)
        sel->showTreeForThis();
}

#endif