Position previousCandidate(const Position& position)
{
PositionIterator p = position;
while (!p.atStart()) {
p.decrement();
if (p.isCandidate())
return p;
}
return Position();
}
// 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;
}
