visibleposition.cpp

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                    while (InlineBox* prevBox = box->prevLeafChild()) {
                        if (prevBox->bidiLevel() < level)
                            break;
                        box = prevBox;
                    }
                    if (box->bidiLevel() == level)
                        break;
                    level = box->bidiLevel();
                    while (InlineBox* nextBox = box->nextLeafChild()) {
                        if (nextBox->bidiLevel() < level)
                            break;
                        box = nextBox;
                    }
                    if (box->bidiLevel() == level)
                        break;
                    level = box->bidiLevel();
                }
                renderer = box->renderer();
                offset = primaryDirection == LTR ? box->caretMaxOffset() : box->caretMinOffset();
            }
            break;
        }

        p = Position(renderer->node(), offset);

        if (p.isCandidate() && p.downstream() != downstreamStart || p.atStart() || p.atEnd())
            return p;
    }
}

VisiblePosition VisiblePosition::right(bool stayInEditableContent) const
{
    Position pos = rightVisuallyDistinctCandidate();
    if (pos.atStart() || pos.atEnd())
        return VisiblePosition();

    VisiblePosition right = VisiblePosition(pos, DOWNSTREAM);
    ASSERT(right != *this);

    if (!stayInEditableContent)
        return right;

    // FIXME: This may need to do something different from "after".
    return honorEditableBoundaryAtOrAfter(right);
}

VisiblePosition VisiblePosition::honorEditableBoundaryAtOrBefore(const VisiblePosition &pos) const
{
    if (pos.isNull())
        return pos;
    
    Node* highestRoot = highestEditableRoot(deepEquivalent());
    
    // Return empty position if pos is not somewhere inside the editable region containing this position
    if (highestRoot && !pos.deepEquivalent().node()->isDescendantOf(highestRoot))
        return VisiblePosition();
        
    // Return pos itself if the two are from the very same editable region, or both are non-editable
    // FIXME: In the non-editable case, just because the new position is non-editable doesn't mean movement
    // to it is allowed.  VisibleSelection::adjustForEditableContent has this problem too.
    if (highestEditableRoot(pos.deepEquivalent()) == highestRoot)
        return pos;
  
    // Return empty position if this position is non-editable, but pos is editable
    // FIXME: Move to the previous non-editable region.
    if (!highestRoot)
        return VisiblePosition();

    // Return the last position before pos that is in the same editable region as this position
    return lastEditablePositionBeforePositionInRoot(pos.deepEquivalent(), highestRoot);
}

VisiblePosition VisiblePosition::honorEditableBoundaryAtOrAfter(const VisiblePosition &pos) const
{
    if (pos.isNull())
        return pos;
    
    Node* highestRoot = highestEditableRoot(deepEquivalent());
    
    // Return empty position if pos is not somewhere inside the editable region containing this position
    if (highestRoot && !pos.deepEquivalent().node()->isDescendantOf(highestRoot))
        return VisiblePosition();
    
    // Return pos itself if the two are from the very same editable region, or both are non-editable
    // FIXME: In the non-editable case, just because the new position is non-editable doesn't mean movement
    // to it is allowed.  VisibleSelection::adjustForEditableContent has this problem too.
    if (highestEditableRoot(pos.deepEquivalent()) == highestRoot)
        return pos;

    // Return empty position if this position is non-editable, but pos is editable
    // FIXME: Move to the next non-editable region.
    if (!highestRoot)
        return VisiblePosition();

    // Return the next position after pos that is in the same editable region as this position
    return firstEditablePositionAfterPositionInRoot(pos.deepEquivalent(), highestRoot);
}

static Position canonicalizeCandidate(const Position& candidate)
{
    if (candidate.isNull())
        return Position();
    ASSERT(candidate.isCandidate());
    Position upstream = candidate.upstream();
    if (upstream.isCandidate())
        return upstream;
    return candidate;
}

Position VisiblePosition::canonicalPosition(const Position& position)
{
    // FIXME (9535):  Canonicalizing to the leftmost candidate means that if we're at a line wrap, we will 
    // ask renderers to paint downstream carets for other renderers.
    // To fix this, we need to either a) add code to all paintCarets to pass the responsibility off to
    // the appropriate renderer for VisiblePosition's like these, or b) canonicalize to the rightmost candidate
    // unless the affinity is upstream.
    Node* node = position.node();
    if (!node)
        return Position();

    node->document()->updateLayoutIgnorePendingStylesheets();

    Position candidate = position.upstream();
    if (candidate.isCandidate())
        return candidate;
    candidate = position.downstream();
    if (candidate.isCandidate())
        return candidate;

    // When neither upstream or downstream gets us to a candidate (upstream/downstream won't leave 
    // blocks or enter new ones), we search forward and backward until we find one.
    Position next = canonicalizeCandidate(nextCandidate(position));
    Position prev = canonicalizeCandidate(previousCandidate(position));
    Node* nextNode = next.node();
    Node* prevNode = prev.node();

    // The new position must be in the same editable element. Enforce that first.
    // Unless the descent is from a non-editable html element to an editable body.
    if (node->hasTagName(htmlTag) && !node->isContentEditable() && node->document()->body() && node->document()->body()->isContentEditable())
        return next.isNotNull() ? next : prev;

    Node* editingRoot = editableRootForPosition(position);
        
    // If the html element is editable, descending into its body will look like a descent 
    // from non-editable to editable content since rootEditableElement() always stops at the body.
    if (editingRoot && editingRoot->hasTagName(htmlTag) || position.node()->isDocumentNode())
        return next.isNotNull() ? next : prev;
        
    bool prevIsInSameEditableElement = prevNode && editableRootForPosition(prev) == editingRoot;
    bool nextIsInSameEditableElement = nextNode && editableRootForPosition(next) == editingRoot;
    if (prevIsInSameEditableElement && !nextIsInSameEditableElement)
        return prev;

    if (nextIsInSameEditableElement && !prevIsInSameEditableElement)
        return next;

    if (!nextIsInSameEditableElement && !prevIsInSameEditableElement)
        return Position();

    // The new position should be in the same block flow element. Favor that.
    Node *originalBlock = node->enclosingBlockFlowElement();
    bool nextIsOutsideOriginalBlock = !nextNode->isDescendantOf(originalBlock) && nextNode != originalBlock;
    bool prevIsOutsideOriginalBlock = !prevNode->isDescendantOf(originalBlock) && prevNode != originalBlock;
    if (nextIsOutsideOriginalBlock && !prevIsOutsideOriginalBlock)
        return prev;
        
    return next;
}

UChar VisiblePosition::characterAfter() const
{
    // We canonicalize to the first of two equivalent candidates, but the second of the two candidates
    // is the one that will be inside the text node containing the character after this visible position.
    Position pos = m_deepPosition.downstream();
    Node* node = pos.node();
    if (!node || !node->isTextNode())
        return 0;
    Text* textNode = static_cast<Text*>(pos.node());
    int offset = pos.offset();
    if ((unsigned)offset >= textNode->length())
        return 0;
    return textNode->data()[offset];
}

IntRect VisiblePosition::localCaretRect(RenderObject*& renderer) const
{
    Node* node = m_deepPosition.node();
    if (!node) {
        renderer = 0;
        return IntRect();
    }
    
    renderer = node->renderer();
    if (!renderer)
        return IntRect();

    InlineBox* inlineBox;
    int caretOffset;
    getInlineBoxAndOffset(inlineBox, caretOffset);

    if (inlineBox)
        renderer = inlineBox->renderer();

    return renderer->localCaretRect(inlineBox, caretOffset);
}

IntRect VisiblePosition::absoluteCaretBounds() const
{
    RenderObject* renderer;
    IntRect localRect = localCaretRect(renderer);
    if (localRect.isEmpty() || !renderer)
        return IntRect();

    return renderer->localToAbsoluteQuad(FloatRect(localRect)).enclosingBoundingBox();
}

int VisiblePosition::xOffsetForVerticalNavigation() const
{
    RenderObject* renderer;
    IntRect localRect = localCaretRect(renderer);
    if (localRect.isEmpty() || !renderer)
        return 0;

    // This ignores transforms on purpose, for now. Vertical navigation is done
    // without consulting transforms, so that 'up' in transformed text is 'up'
    // relative to the text, not absolute 'up'.
    return renderer->localToAbsolute(localRect.location()).x();
}

void VisiblePosition::debugPosition(const char* msg) const
{
    if (isNull())
        fprintf(stderr, "Position [%s]: null\n", msg);
    else
        fprintf(stderr, "Position [%s]: %s [%p] at %d\n", msg, m_deepPosition.node()->nodeName().utf8().data(), m_deepPosition.node(), m_deepPosition.offset());
}

#ifndef NDEBUG

void VisiblePosition::formatForDebugger(char* buffer, unsigned length) const
{
    m_deepPosition.formatForDebugger(buffer, length);
}

void VisiblePosition::showTreeForThis() const
{
    m_deepPosition.showTreeForThis();
}

#endif

PassRefPtr<Range> makeRange(const VisiblePosition &start, const VisiblePosition &end)
{
    if (start.isNull() || end.isNull())
        return 0;
    
    Position s = rangeCompliantEquivalent(start);
    Position e = rangeCompliantEquivalent(end);
    return Range::create(s.node()->document(), s.node(), s.offset(), e.node(), e.offset());
}

VisiblePosition startVisiblePosition(const Range *r, EAffinity affinity)
{
    int exception = 0;
    return VisiblePosition(r->startContainer(exception), r->startOffset(exception), affinity);
}

VisiblePosition endVisiblePosition(const Range *r, EAffinity affinity)
{
    int exception = 0;
    return VisiblePosition(r->endContainer(exception), r->endOffset(exception), affinity);
}

bool setStart(Range *r, const VisiblePosition &visiblePosition)
{
    if (!r)
        return false;
    Position p = rangeCompliantEquivalent(visiblePosition);
    int code = 0;
    r->setStart(p.node(), p.offset(), code);
    return code == 0;
}

bool setEnd(Range *r, const VisiblePosition &visiblePosition)
{
    if (!r)
        return false;
    Position p = rangeCompliantEquivalent(visiblePosition);
    int code = 0;
    r->setEnd(p.node(), p.offset(), code);
    return code == 0;
}

Node *enclosingBlockFlowElement(const VisiblePosition &visiblePosition)
{
    if (visiblePosition.isNull())
        return NULL;

    return visiblePosition.deepEquivalent().node()->enclosingBlockFlowElement();
}

bool isFirstVisiblePositionInNode(const VisiblePosition &visiblePosition, const Node *node)
{
    if (visiblePosition.isNull())
        return false;
    
    if (!visiblePosition.deepEquivalent().node()->isDescendantOf(node))
        return false;
        
    VisiblePosition previous = visiblePosition.previous();
    return previous.isNull() || !previous.deepEquivalent().node()->isDescendantOf(node);
}

bool isLastVisiblePositionInNode(const VisiblePosition &visiblePosition, const Node *node)
{
    if (visiblePosition.isNull())
        return false;
    
    if (!visiblePosition.deepEquivalent().node()->isDescendantOf(node))
        return false;
                
    VisiblePosition next = visiblePosition.next();
    return next.isNull() || !next.deepEquivalent().node()->isDescendantOf(node);
}

}  // namespace WebCore

#ifndef NDEBUG

void showTree(const WebCore::VisiblePosition* vpos)
{
    if (vpos)
        vpos->showTreeForThis();
}

void showTree(const WebCore::VisiblePosition& vpos)
{
    vpos.showTreeForThis();
}

#endif