/**
* @param entry Entry to touch.
* @return {@code True} if new node has been added to queue by this call.
*/
private boolean touch(EvictableEntry<K, V> entry) {
Node<EvictableEntry<K, V>> node = entry.meta();
// Entry has not been enqueued yet.
if (node == null) {
while (true) {
node = queue.offerLastx(entry);
if (entry.putMetaIfAbsent(node) != null) {
// Was concurrently added, need to clear it from queue.
queue.unlinkx(node);
// Queue has not been changed.
return false;
} else if (node.item() != null) {
if (!entry.isCached()) {
// Was concurrently evicted, need to clear it from queue.
queue.unlinkx(node);
return false;
}
memSize.add(entry.size());
return true;
}
// If node was unlinked by concurrent shrink() call, we must repeat the whole cycle.
else if (!entry.removeMeta(node)) return false;
}
} else if (queue.unlinkx(node)) {
// Move node to tail.
Node<EvictableEntry<K, V>> newNode = queue.offerLastx(entry);
if (!entry.replaceMeta(node, newNode))
// Was concurrently added, need to clear it from queue.
queue.unlinkx(newNode);
}
// Entry is already in queue.
return false;
}
