static bool findPlaceForCounter(RenderObject* object, const AtomicString& counterName,
bool isReset, CounterNode*& parent, CounterNode*& previousSibling)
{
// Find the appropriate previous sibling for insertion into the parent node
// by searching in render tree order for a child of the counter.
parent = 0;
previousSibling = 0;
RenderObject* resetCandidate = isReset ? object->parent() : previousSiblingOrParent(object);
RenderObject* prevCounterCandidate = object;
CounterNode* candidateCounter = 0;
// When a reset counter is chosen as candidateCounter, we'll
// decide the new node should be a child of the reset node or a
// sibling or the reset node. This flag controls it.
bool createChildForReset = true;
while ((prevCounterCandidate = prevCounterCandidate->previousInPreOrder())) {
CounterNode* c = counter(prevCounterCandidate, counterName, false);
if (prevCounterCandidate == resetCandidate) {
if (!candidateCounter) {
candidateCounter = c;
createChildForReset = true;
}
if (candidateCounter) {
if (createChildForReset && candidateCounter->isReset()) {
parent = candidateCounter;
previousSibling = 0;
} else {
parent = candidateCounter->parent();
previousSibling = candidateCounter;
}
return true;
}
resetCandidate = previousSiblingOrParent(resetCandidate);
} else if (c) {
if (c->isReset()) {
if (c->parent()) {
// The new node may be the next sibling of this reset node.
createChildForReset = false;
candidateCounter = c;
} else {
createChildForReset = true;
candidateCounter = 0;
}
} else if (!candidateCounter) {
createChildForReset = true;
candidateCounter = c;
}
}
}
return false;
}
static bool findPlaceForCounter(RenderObject* counterOwner, const AtomicString& identifier, bool isReset, RefPtr<CounterNode>& parent, RefPtr<CounterNode>& previousSibling)
{
// We cannot stop searching for counters with the same identifier before we also
// check this renderer, because it may affect the positioning in the tree of our counter.
RenderObject* searchEndRenderer = previousSiblingOrParent(counterOwner);
// We check renderers in preOrder from the renderer that our counter is attached to
// towards the begining of the document for counters with the same identifier as the one
// we are trying to find a place for. This is the next renderer to be checked.
RenderObject* currentRenderer = previousInPreOrder(counterOwner);
previousSibling = 0;
RefPtr<CounterNode> previousSiblingProtector = 0;
while (currentRenderer) {
CounterNode* currentCounter = makeCounterNode(currentRenderer, identifier, false);
if (searchEndRenderer == currentRenderer) {
// We may be at the end of our search.
if (currentCounter) {
// We have a suitable counter on the EndSearchRenderer.
if (previousSiblingProtector) { // But we already found another counter that we come after.
if (currentCounter->actsAsReset()) {
// We found a reset counter that is on a renderer that is a sibling of ours or a parent.
if (isReset && areRenderersElementsSiblings(currentRenderer, counterOwner)) {
// We are also a reset counter and the previous reset was on a sibling renderer
// hence we are the next sibling of that counter if that reset is not a root or
// we are a root node if that reset is a root.
parent = currentCounter->parent();
previousSibling = parent ? currentCounter : 0;
return parent;
}
// We are not a reset node or the previous reset must be on an ancestor of our owner renderer
// hence we must be a child of that reset counter.
parent = currentCounter;
// In some cases renders can be reparented (ex. nodes inside a table but not in a column or row).
// In these cases the identified previousSibling will be invalid as its parent is different from
// our identified parent.
if (previousSiblingProtector->parent() != currentCounter)
previousSiblingProtector = 0;
previousSibling = previousSiblingProtector.get();
return true;
}
// CurrentCounter, the counter at the EndSearchRenderer, is not reset.
if (!isReset || !areRenderersElementsSiblings(currentRenderer, counterOwner)) {
// If the node we are placing is not reset or we have found a counter that is attached
// to an ancestor of the placed counter's owner renderer we know we are a sibling of that node.
if (currentCounter->parent() != previousSiblingProtector->parent())
return false;
parent = currentCounter->parent();
previousSibling = previousSiblingProtector.get();
return true;
}
} else {
// We are at the potential end of the search, but we had no previous sibling candidate
// In this case we follow pretty much the same logic as above but no ASSERTs about
// previousSibling, and when we are a sibling of the end counter we must set previousSibling
// to currentCounter.
if (currentCounter->actsAsReset()) {
if (isReset && areRenderersElementsSiblings(currentRenderer, counterOwner)) {
parent = currentCounter->parent();
previousSibling = currentCounter;
return parent;
}
parent = currentCounter;
previousSibling = previousSiblingProtector.get();
return true;
}
if (!isReset || !areRenderersElementsSiblings(currentRenderer, counterOwner)) {
parent = currentCounter->parent();
previousSibling = currentCounter;
return true;
}
previousSiblingProtector = currentCounter;
}
}
// We come here if the previous sibling or parent of our owner renderer had no
// good counter, or we are a reset node and the counter on the previous sibling
// of our owner renderer was not a reset counter.
// Set a new goal for the end of the search.
searchEndRenderer = previousSiblingOrParent(currentRenderer);
} else {
// We are searching descendants of a previous sibling of the renderer that the
// counter being placed is attached to.
if (currentCounter) {
// We found a suitable counter.
if (previousSiblingProtector) {
// Since we had a suitable previous counter before, we should only consider this one as our
// previousSibling if it is a reset counter and hence the current previousSibling is its child.
if (currentCounter->actsAsReset()) {
previousSiblingProtector = currentCounter;
// We are no longer interested in previous siblings of the currentRenderer or their children
// as counters they may have attached cannot be the previous sibling of the counter we are placing.
currentRenderer = parentElement(currentRenderer)->renderer();
continue;
}
} else
previousSiblingProtector = currentCounter;
currentRenderer = previousSiblingOrParent(currentRenderer);
continue;
}
}
// This function is designed so that the same test is not done twice in an iteration, except for this one
// which may be done twice in some cases. Rearranging the decision points though, to accommodate this
// performance improvement would create more code duplication than is worthwhile in my oppinion and may further
// impede the readability of this already complex algorithm.
if (previousSiblingProtector)
currentRenderer = previousSiblingOrParent(currentRenderer);
else
currentRenderer = previousInPreOrder(currentRenderer);
}
return false;
}
