C++ RenderObject::caretMaxOffset方法代码示例

Position Position::upstream(EStayInBlock stayInBlock) const
{
    Position start = equivalentDeepPosition();
    NodeImpl *startNode = start.node();
    if (!startNode)
        return Position();

    NodeImpl *block = startNode->enclosingBlockFlowOrTableElement();
    Position lastVisible;
    
    PositionIterator it(start);
    for (; !it.atStart(); it.previous()) {
        NodeImpl *currentNode = it.current().node();

        if (stayInBlock) {
            NodeImpl *currentBlock = currentNode->enclosingBlockFlowOrTableElement();
            if (block != currentBlock)
                return it.next();
        }

        RenderObject *renderer = currentNode->renderer();
        if (!renderer)
            continue;

        if (renderer->style()->visibility() != VISIBLE)
            continue;

        lastVisible = it.current();

        if (renderer->isReplaced() || renderer->isBR()) {
            if (it.current().offset() >= renderer->caretMaxOffset())
                return Position(currentNode, renderer->caretMaxOffset());
            else
                continue;
        }

        if (renderer->isText() && static_cast<RenderText *>(renderer)->firstTextBox()) {
            if (currentNode != startNode)
                return Position(currentNode, renderer->caretMaxOffset());

            if (it.current().offset() < 0)
                continue;
            uint textOffset = it.current().offset();

            RenderText *textRenderer = static_cast<RenderText *>(renderer);
            for (InlineTextBox *box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {
                if (textOffset > box->start() && textOffset <= box->start() + box->len())
                    return it.current();
                else if (box != textRenderer->lastTextBox() && 
                         !box->nextOnLine() && 
                         textOffset == box->start() + box->len() + 1)
                    return it.current();
            }
        }
    }
    
    return lastVisible.isNotNull() ? lastVisible : *this;
}

VisiblePosition endOfParagraph(const VisiblePosition &c)
{    
    if (c.isNull())
        return VisiblePosition();

    Position p = c.deepEquivalent();
    Node* startNode = p.node();

    if (isRenderedAsNonInlineTableImageOrHR(startNode))
        return lastDeepEditingPositionForNode(startNode);
    
    Node* startBlock = enclosingBlock(startNode);
    Node *stayInsideBlock = startBlock;
    
    Node *node = startNode;
    int offset = p.deprecatedEditingOffset();

    Node *n = startNode;
    while (n) {
        if (n->isContentEditable() != startNode->isContentEditable())
            break;
        RenderObject *r = n->renderer();
        if (!r) {
            n = n->traverseNextNode(stayInsideBlock);
            continue;
        }
        RenderStyle *style = r->style();
        if (style->visibility() != VISIBLE) {
            n = n->traverseNextNode(stayInsideBlock);
            continue;
        }
        
        if (r->isBR() || isBlock(n))
            break;
            
        // FIXME: We avoid returning a position where the renderer can't accept the caret.
        // We should probably do this in other cases such as startOfParagraph.
        if (r->isText() && r->caretMaxRenderedOffset() > 0) {
            int length = toRenderText(r)->textLength();
            if (style->preserveNewline()) {
                const UChar* chars = toRenderText(r)->characters();
                int o = n == startNode ? offset : 0;
                for (int i = o; i < length; ++i)
                    if (chars[i] == '\n')
                        return VisiblePosition(n, i, DOWNSTREAM);
            }
            node = n;
            offset = r->caretMaxOffset();
            n = n->traverseNextNode(stayInsideBlock);
        } else if (editingIgnoresContent(n) || isTableElement(n)) {
            node = n;
            offset = lastOffsetForEditing(n);
            n = n->traverseNextSibling(stayInsideBlock);
        } else
            n = n->traverseNextNode(stayInsideBlock);
    }

    return VisiblePosition(node, offset, DOWNSTREAM);
}

bool Position::inRenderedContent() const
{
    if (isNull())
        return false;
        
    RenderObject *renderer = node()->renderer();
    if (!renderer)
        return false;
    
    if (renderer->style()->visibility() != VISIBLE)
        return false;

    // FIXME: This check returns false for a <br> at the end of a line!
    if (renderer->isBR() && static_cast<RenderText *>(renderer)->firstTextBox()) {
        return offset() == 0;
    }
    else if (renderer->isText()) {
        RenderText *textRenderer = static_cast<RenderText *>(renderer);
        for (InlineTextBox *box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {
            if (offset() >= box->m_start && offset() <= box->m_start + box->m_len) {
                return true;
            }
            else if (offset() < box->m_start) {
                // The offset we're looking for is before this node
                // this means the offset must be in content that is
                // not rendered. Return false.
                return false;
            }
        }
    }
    else if (offset() >= renderer->caretMinOffset() && offset() <= renderer->caretMaxOffset()) {
        // return true for replaced elements, for inline flows if they have a line box
        // and for blocks if they are empty
        if (renderer->isReplaced() ||
            (renderer->isInlineFlow() && static_cast<RenderFlow *>(renderer)->firstLineBox()) ||
            (renderer->isBlockFlow() && !renderer->firstChild() && renderer->height()))
            return true;
    }
    
    return false;
}

// p.upstream() returns the start of the range of positions that map to the same VisiblePosition as P.
Position Position::upstream() const
{
    Node* startNode = node();
    if (!startNode)
        return Position();
    
    // iterate backward from there, looking for a qualified position
    Node* block = enclosingBlock(startNode);
    PositionIterator lastVisible = *this;
    PositionIterator currentPos = lastVisible;
    Node* originalRoot = node()->rootEditableElement();
    for (; !currentPos.atStart(); currentPos.decrement()) {
        Node* currentNode = currentPos.node();
        
        if (currentNode->rootEditableElement() != originalRoot)
            break;

        // Don't enter a new enclosing block flow or table element.  There is code below that
        // terminates early if we're about to leave an enclosing block flow or table element.
        if (block != enclosingBlock(currentNode))
            return lastVisible;

        // skip position in unrendered or invisible node
        RenderObject* renderer = currentNode->renderer();
        if (!renderer || renderer->style()->visibility() != VISIBLE)
            continue;
                 
        // track last visible streamer position
        if (isStreamer(currentPos))
            lastVisible = currentPos;
        
        // Don't leave a block flow or table element.  We could rely on code above to terminate and 
        // return lastVisible on the next iteration, but we terminate early.
        if (currentNode == enclosingBlock(currentNode) && currentPos.atStartOfNode())
            return lastVisible;
            
        // Return position after brs, tables, and nodes which have content that can be ignored.
        if (editingIgnoresContent(currentNode) || renderer->isBR() || isTableElement(currentNode)) {
            if (currentPos.atEndOfNode())
                return Position(currentNode, maxDeepOffset(currentNode));
            continue;
        }

        // return current position if it is in rendered text
        if (renderer->isText() && static_cast<RenderText*>(renderer)->firstTextBox()) {
            if (currentNode != startNode) {
                // This assertion fires in layout tests in the case-transform.html test because
                // of a mix-up between offsets in the text in the DOM tree with text in the
                // render tree which can have a different length due to case transformation.
                // Until we resolve that, disable this so we can run the layout tests!
                //ASSERT(currentOffset >= renderer->caretMaxOffset());
                return Position(currentNode, renderer->caretMaxOffset());
            }

            unsigned textOffset = currentPos.offsetInLeafNode();
            RenderText* textRenderer = static_cast<RenderText*>(renderer);
            for (InlineTextBox* box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {
                if (textOffset > box->start() && textOffset <= box->start() + box->len())
                    return currentPos;
                    
                if (box != textRenderer->lastTextBox() && 
                    !box->nextOnLine() && 
                    textOffset == box->start() + box->len() + 1)
                    return currentPos;
            }
        }
    }

    return lastVisible;
}