void MemoryCache::pruneDeadResources()
{
unsigned capacity = deadCapacity();
if (!m_deadSize || (capacity && m_deadSize <= capacity))
return;
unsigned targetSize = static_cast<unsigned>(capacity * cTargetPrunePercentage); // Cut by a percentage to avoid immediately pruning again.
int size = m_allResources.size();
// See if we have any purged resources we can evict.
for (int i = 0; i < size; i++) {
Resource* current = m_allResources[i].m_tail;
while (current) {
Resource* prev = current->m_prevInAllResourcesList;
if (current->wasPurged()) {
ASSERT(!current->hasClients());
ASSERT(!current->isPreloaded());
evict(current);
}
current = prev;
}
}
if (targetSize && m_deadSize <= targetSize)
return;
bool canShrinkLRULists = true;
for (int i = size - 1; i >= 0; i--) {
// Remove from the tail, since this is the least frequently accessed of the objects.
Resource* current = m_allResources[i].m_tail;
// First flush all the decoded data in this queue.
while (current) {
// Protect 'previous' so it can't get deleted during destroyDecodedData().
ResourcePtr<Resource> previous = current->m_prevInAllResourcesList;
ASSERT(!previous || previous->inCache());
if (!current->hasClients() && !current->isPreloaded() && current->isLoaded()) {
// Destroy our decoded data. This will remove us from
// m_liveDecodedResources, and possibly move us to a different
// LRU list in m_allResources.
current->destroyDecodedData();
if (targetSize && m_deadSize <= targetSize)
return;
}
// Decoded data may reference other resources. Stop iterating if 'previous' somehow got
// kicked out of cache during destroyDecodedData().
if (previous && !previous->inCache())
break;
current = previous.get();
}
// Now evict objects from this queue.
current = m_allResources[i].m_tail;
while (current) {
ResourcePtr<Resource> previous = current->m_prevInAllResourcesList;
ASSERT(!previous || previous->inCache());
if (!current->hasClients() && !current->isPreloaded() && !current->isCacheValidator()) {
evict(current);
if (targetSize && m_deadSize <= targetSize)
return;
}
if (previous && !previous->inCache())
break;
current = previous.get();
}
// Shrink the vector back down so we don't waste time inspecting
// empty LRU lists on future prunes.
if (m_allResources[i].m_head)
canShrinkLRULists = false;
else if (canShrinkLRULists)
m_allResources.resize(i);
}
}
