void LayoutMultiColumnFlowThread::createAndInsertMultiColumnSet(LayoutBox* insertBefore)
{
LayoutBlockFlow* multicolContainer = multiColumnBlockFlow();
LayoutMultiColumnSet* newSet = LayoutMultiColumnSet::createAnonymous(*this, multicolContainer->styleRef());
multicolContainer->LayoutBlock::addChild(newSet, insertBefore);
invalidateColumnSets();
// We cannot handle immediate column set siblings (and there's no need for it, either).
// There has to be at least one spanner separating them.
ASSERT(!newSet->previousSiblingMultiColumnBox() || !newSet->previousSiblingMultiColumnBox()->isLayoutMultiColumnSet());
ASSERT(!newSet->nextSiblingMultiColumnBox() || !newSet->nextSiblingMultiColumnBox()->isLayoutMultiColumnSet());
}
void LayoutMultiColumnFlowThread::createAndInsertSpannerPlaceholder(LayoutBox* spannerObjectInFlowThread, LayoutObject* insertedBeforeInFlowThread)
{
LayoutBox* insertBeforeColumnBox = nullptr;
LayoutMultiColumnSet* setToSplit = nullptr;
if (insertedBeforeInFlowThread) {
// The spanner is inserted before something. Figure out what this entails. If the
// next object is a spanner too, it means that we can simply insert a new spanner
// placeholder in front of its placeholder.
insertBeforeColumnBox = insertedBeforeInFlowThread->spannerPlaceholder();
if (!insertBeforeColumnBox) {
// The next object isn't a spanner; it's regular column content. Examine what
// comes right before us in the flow thread, then.
LayoutObject* previousLayoutObject = previousInPreOrderSkippingOutOfFlow(this, spannerObjectInFlowThread);
if (!previousLayoutObject || previousLayoutObject == this) {
// The spanner is inserted as the first child of the multicol container,
// which means that we simply insert a new spanner placeholder at the
// beginning.
insertBeforeColumnBox = firstMultiColumnBox();
} else if (LayoutMultiColumnSpannerPlaceholder* previousPlaceholder = containingColumnSpannerPlaceholder(previousLayoutObject)) {
// Before us is another spanner. We belong right after it then.
insertBeforeColumnBox = previousPlaceholder->nextSiblingMultiColumnBox();
} else {
// We're inside regular column content with both feet. Find out which column
// set this is. It needs to be split it into two sets, so that we can insert
// a new spanner placeholder between them.
setToSplit = mapDescendantToColumnSet(previousLayoutObject);
ASSERT(setToSplit == mapDescendantToColumnSet(insertedBeforeInFlowThread));
insertBeforeColumnBox = setToSplit->nextSiblingMultiColumnBox();
// We've found out which set that needs to be split. Now proceed to
// inserting the spanner placeholder, and then insert a second column set.
}
}
ASSERT(setToSplit || insertBeforeColumnBox);
}
LayoutBlockFlow* multicolContainer = multiColumnBlockFlow();
LayoutMultiColumnSpannerPlaceholder* newPlaceholder = LayoutMultiColumnSpannerPlaceholder::createAnonymous(multicolContainer->styleRef(), *spannerObjectInFlowThread);
ASSERT(!insertBeforeColumnBox || insertBeforeColumnBox->parent() == multicolContainer);
multicolContainer->LayoutBlock::addChild(newPlaceholder, insertBeforeColumnBox);
spannerObjectInFlowThread->setSpannerPlaceholder(*newPlaceholder);
if (setToSplit)
createAndInsertMultiColumnSet(insertBeforeColumnBox);
}