/* Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de) Copyright (C) 2001 Dirk Mueller (mueller@kde.org) Copyright (C) 2002 Waldo Bastian (bastian@kde.org) Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include "config.h" #include "Cache.h" #include "CachedCSSStyleSheet.h" #include "CachedFont.h" #include "CachedImage.h" #include "CachedScript.h" #include "CachedXSLStyleSheet.h" #include "DocLoader.h" #include "Document.h" #include "FrameLoader.h" #include "FrameLoaderTypes.h" #include "FrameView.h" #include "Image.h" #include "ResourceHandle.h" #include "SecurityOrigin.h" #include <stdio.h> #include <wtf/CurrentTime.h> using namespace std; namespace WebCore { static const int cDefaultCacheCapacity = 8192 * 1024; static const double cMinDelayBeforeLiveDecodedPrune = 1; // Seconds. static const float cTargetPrunePercentage = .95f; // Percentage of capacity toward which we prune, to avoid immediately pruning again. static const double cDefaultDecodedDataDeletionInterval = 0; Cache* cache() { static Cache* staticCache = new Cache; return staticCache; } Cache::Cache() : m_disabled(false) , m_pruneEnabled(true) , m_inPruneDeadResources(false) , m_capacity(cDefaultCacheCapacity) , m_minDeadCapacity(0) , m_maxDeadCapacity(cDefaultCacheCapacity) , m_deadDecodedDataDeletionInterval(cDefaultDecodedDataDeletionInterval) , m_liveSize(0) , m_deadSize(0) { } static CachedResource* createResource(CachedResource::Type type, const KURL& url, const String& charset) { switch (type) { case CachedResource::ImageResource: return new CachedImage(url.string()); case CachedResource::CSSStyleSheet: return new CachedCSSStyleSheet(url.string(), charset); case CachedResource::Script: return new CachedScript(url.string(), charset); case CachedResource::FontResource: return new CachedFont(url.string()); #if ENABLE(XSLT) case CachedResource::XSLStyleSheet: return new CachedXSLStyleSheet(url.string()); #endif #if ENABLE(XBL) case CachedResource::XBLStyleSheet: return new CachedXBLDocument(url.string()); #endif default: break; } return 0; } CachedResource* Cache::requestResource(DocLoader* docLoader, CachedResource::Type type, const KURL& url, const String& charset, bool requestIsPreload) { // FIXME: Do we really need to special-case an empty URL? // Would it be better to just go on with the cache code and let it fail later? if (url.isEmpty()) return 0; // Look up the resource in our map. CachedResource* resource = resourceForURL(url.string()); if (resource && requestIsPreload && !resource->isPreloaded()) return 0; if (SecurityOrigin::restrictAccessToLocal() && !SecurityOrigin::canLoad(url, String(), docLoader->doc())) { Document* doc = docLoader->doc(); if (doc && !requestIsPreload) FrameLoader::reportLocalLoadFailed(doc->frame(), url.string()); return 0; } if (!resource) { // The resource does not exist. Create it. resource = createResource(type, url, charset); ASSERT(resource); // Pretend the resource is in the cache, to prevent it from being deleted during the load() call. // FIXME: CachedResource should just use normal refcounting instead. resource->setInCache(true); resource->load(docLoader); if (resource->errorOccurred()) { // We don't support immediate loads, but we do support immediate failure. // In that case we should to delete the resource now and return 0 because otherwise // it would leak if no ref/deref was ever done on it. resource->setInCache(false); delete resource; return 0; } if (!disabled()) m_resources.set(url.string(), resource); // The size will be added in later once the resource is loaded and calls back to us with the new size. else { // Kick the resource out of the cache, because the cache is disabled. resource->setInCache(false); resource->setDocLoader(docLoader); } } if (resource->type() != type) return 0; if (!disabled()) { // This will move the resource to the front of its LRU list and increase its access count. resourceAccessed(resource); } return resource; } CachedCSSStyleSheet* Cache::requestUserCSSStyleSheet(DocLoader* docLoader, const String& url, const String& charset) { CachedCSSStyleSheet* userSheet; if (CachedResource* existing = resourceForURL(url)) { if (existing->type() != CachedResource::CSSStyleSheet) return 0; userSheet = static_cast<CachedCSSStyleSheet*>(existing); } else { userSheet = new CachedCSSStyleSheet(url, charset); // Pretend the resource is in the cache, to prevent it from being deleted during the load() call. // FIXME: CachedResource should just use normal refcounting instead. userSheet->setInCache(true); // Don't load incrementally, skip load checks, don't send resource load callbacks. userSheet->load(docLoader, false, SkipSecurityCheck, false); if (!disabled()) m_resources.set(url, userSheet); else userSheet->setInCache(false); } if (!disabled()) { // This will move the resource to the front of its LRU list and increase its access count. resourceAccessed(userSheet); } return userSheet; } void Cache::revalidateResource(CachedResource* resource, DocLoader* docLoader) { ASSERT(resource); ASSERT(resource->inCache()); ASSERT(resource == m_resources.get(resource->url())); ASSERT(!disabled()); if (resource->resourceToRevalidate()) return; if (!resource->canUseCacheValidator()) { evict(resource); return; } const String& url = resource->url(); CachedResource* newResource = createResource(resource->type(), KURL(ParsedURLString, url), resource->encoding()); newResource->setResourceToRevalidate(resource); evict(resource); m_resources.set(url, newResource); newResource->setInCache(true); resourceAccessed(newResource); newResource->load(docLoader); } void Cache::revalidationSucceeded(CachedResource* revalidatingResource, const ResourceResponse& response) { CachedResource* resource = revalidatingResource->resourceToRevalidate(); ASSERT(resource); ASSERT(!resource->inCache()); ASSERT(resource->isLoaded()); ASSERT(revalidatingResource->inCache()); evict(revalidatingResource); ASSERT(!m_resources.get(resource->url())); m_resources.set(resource->url(), resource); resource->setInCache(true); resource->updateResponseAfterRevalidation(response); insertInLRUList(resource); int delta = resource->size(); if (resource->decodedSize() && resource->hasClients()) insertInLiveDecodedResourcesList(resource); if (delta) adjustSize(resource->hasClients(), delta); revalidatingResource->switchClientsToRevalidatedResource(); // this deletes the revalidating resource revalidatingResource->clearResourceToRevalidate(); } void Cache::revalidationFailed(CachedResource* revalidatingResource) { ASSERT(revalidatingResource->resourceToRevalidate()); revalidatingResource->clearResourceToRevalidate(); } CachedResource* Cache::resourceForURL(const String& url) { CachedResource* resource = m_resources.get(url); if (resource && !resource->makePurgeable(false)) { ASSERT(!resource->hasClients()); evict(resource); return 0; } return resource; } unsigned Cache::deadCapacity() const { // Dead resource capacity is whatever space is not occupied by live resources, bounded by an independent minimum and maximum. unsigned capacity = m_capacity - min(m_liveSize, m_capacity); // Start with available capacity. capacity = max(capacity, m_minDeadCapacity); // Make sure it's above the minimum. capacity = min(capacity, m_maxDeadCapacity); // Make sure it's below the maximum. return capacity; } unsigned Cache::liveCapacity() const { // Live resource capacity is whatever is left over after calculating dead resource capacity. return m_capacity - deadCapacity(); } void Cache::pruneLiveResources() { if (!m_pruneEnabled) return; unsigned capacity = liveCapacity(); if (capacity && m_liveSize <= capacity) return; unsigned targetSize = static_cast<unsigned>(capacity * cTargetPrunePercentage); // Cut by a percentage to avoid immediately pruning again. double currentTime = FrameView::currentPaintTimeStamp(); if (!currentTime) // In case prune is called directly, outside of a Frame paint. currentTime = WTF::currentTime(); // Destroy any decoded data in live objects that we can. // Start from the tail, since this is the least recently accessed of the objects. // The list might not be sorted by the m_lastDecodedAccessTime. The impact // of this weaker invariant is minor as the below if statement to check the // elapsedTime will evaluate to false as the currentTime will be a lot // greater than the current->m_lastDecodedAccessTime. // For more details see: https://bugs.webkit.org/show_bug.cgi?id=30209 CachedResource* current = m_liveDecodedResources.m_tail; while (current) { CachedResource* prev = current->m_prevInLiveResourcesList; ASSERT(current->hasClients()); if (current->isLoaded() && current->decodedSize()) { // Check to see if the remaining resources are too new to prune. double elapsedTime = currentTime - current->m_lastDecodedAccessTime; if (elapsedTime < cMinDelayBeforeLiveDecodedPrune) return; // 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_liveSize <= targetSize) return; } current = prev; } } void Cache::pruneDeadResources() { if (!m_pruneEnabled) return; unsigned capacity = deadCapacity(); if (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(); if (!m_inPruneDeadResources) { // See if we have any purged resources we can evict. for (int i = 0; i < size; i++) { CachedResource* current = m_allResources[i].m_tail; while (current) { CachedResource* 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; m_inPruneDeadResources = true; for (int i = size - 1; i >= 0; i--) { // Remove from the tail, since this is the least frequently accessed of the objects. CachedResource* current = m_allResources[i].m_tail; // First flush all the decoded data in this queue. while (current) { CachedResource* prev = current->m_prevInAllResourcesList; 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) { m_inPruneDeadResources = false; return; } } current = prev; } // Now evict objects from this queue. current = m_allResources[i].m_tail; while (current) { CachedResource* prev = current->m_prevInAllResourcesList; if (!current->hasClients() && !current->isPreloaded() && !current->isCacheValidator()) { evict(current); // If evict() caused pruneDeadResources() to be re-entered, bail out. This can happen when removing an // SVG CachedImage that has subresources. if (!m_inPruneDeadResources) return; if (targetSize && m_deadSize <= targetSize) { m_inPruneDeadResources = false; return; } } current = prev; } // 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); } m_inPruneDeadResources = false; } void Cache::setCapacities(unsigned minDeadBytes, unsigned maxDeadBytes, unsigned totalBytes) { ASSERT(minDeadBytes <= maxDeadBytes); ASSERT(maxDeadBytes <= totalBytes); m_minDeadCapacity = minDeadBytes; m_maxDeadCapacity = maxDeadBytes; m_capacity = totalBytes; prune(); } void Cache::evict(CachedResource* resource) { // The resource may have already been removed by someone other than our caller, // who needed a fresh copy for a reload. See <http://bugs.webkit.org/show_bug.cgi?id=12479#c6>. if (resource->inCache()) { // Remove from the resource map. m_resources.remove(resource->url()); resource->setInCache(false); // Remove from the appropriate LRU list. removeFromLRUList(resource); removeFromLiveDecodedResourcesList(resource); // Subtract from our size totals. int delta = -static_cast<int>(resource->size()); if (delta) adjustSize(resource->hasClients(), delta); } else ASSERT(m_resources.get(resource->url()) != resource); if (resource->canDelete()) delete resource; } void Cache::addDocLoader(DocLoader* docLoader) { m_docLoaders.add(docLoader); } void Cache::removeDocLoader(DocLoader* docLoader) { m_docLoaders.remove(docLoader); } static inline unsigned fastLog2(unsigned i) { unsigned log2 = 0; if (i & (i - 1)) log2 += 1; if (i >> 16) log2 += 16, i >>= 16; if (i >> 8) log2 += 8, i >>= 8; if (i >> 4) log2 += 4, i >>= 4; if (i >> 2) log2 += 2, i >>= 2; if (i >> 1) log2 += 1; return log2; } Cache::LRUList* Cache::lruListFor(CachedResource* resource) { unsigned accessCount = max(resource->accessCount(), 1U); unsigned queueIndex = fastLog2(resource->size() / accessCount); #ifndef NDEBUG resource->m_lruIndex = queueIndex; #endif if (m_allResources.size() <= queueIndex) m_allResources.grow(queueIndex + 1); return &m_allResources[queueIndex]; } void Cache::removeFromLRUList(CachedResource* resource) { // If we've never been accessed, then we're brand new and not in any list. if (resource->accessCount() == 0) return; #if !ASSERT_DISABLED unsigned oldListIndex = resource->m_lruIndex; #endif LRUList* list = lruListFor(resource); #if !ASSERT_DISABLED // Verify that the list we got is the list we want. ASSERT(resource->m_lruIndex == oldListIndex); // Verify that we are in fact in this list. bool found = false; for (CachedResource* current = list->m_head; current; current = current->m_nextInAllResourcesList) { if (current == resource) { found = true; break; } } ASSERT(found); #endif CachedResource* next = resource->m_nextInAllResourcesList; CachedResource* prev = resource->m_prevInAllResourcesList; if (next == 0 && prev == 0 && list->m_head != resource) return; resource->m_nextInAllResourcesList = 0; resource->m_prevInAllResourcesList = 0; if (next) next->m_prevInAllResourcesList = prev; else if (list->m_tail == resource) list->m_tail = prev; if (prev) prev->m_nextInAllResourcesList = next; else if (list->m_head == resource) list->m_head = next; } void Cache::insertInLRUList(CachedResource* resource) { // Make sure we aren't in some list already. ASSERT(!resource->m_nextInAllResourcesList && !resource->m_prevInAllResourcesList); ASSERT(resource->inCache()); ASSERT(resource->accessCount() > 0); LRUList* list = lruListFor(resource); resource->m_nextInAllResourcesList = list->m_head; if (list->m_head) list->m_head->m_prevInAllResourcesList = resource; list->m_head = resource; if (!resource->m_nextInAllResourcesList) list->m_tail = resource; #ifndef NDEBUG // Verify that we are in now in the list like we should be. list = lruListFor(resource); bool found = false; for (CachedResource* current = list->m_head; current; current = current->m_nextInAllResourcesList) { if (current == resource) { found = true; break; } } ASSERT(found); #endif } void Cache::resourceAccessed(CachedResource* resource) { ASSERT(resource->inCache()); // Need to make sure to remove before we increase the access count, since // the queue will possibly change. removeFromLRUList(resource); // If this is the first time the resource has been accessed, adjust the size of the cache to account for its initial size. if (!resource->accessCount()) adjustSize(resource->hasClients(), resource->size()); // Add to our access count. resource->increaseAccessCount(); // Now insert into the new queue. insertInLRUList(resource); } void Cache::removeFromLiveDecodedResourcesList(CachedResource* resource) { // If we've never been accessed, then we're brand new and not in any list. if (!resource->m_inLiveDecodedResourcesList) return; resource->m_inLiveDecodedResourcesList = false; #ifndef NDEBUG // Verify that we are in fact in this list. bool found = false; for (CachedResource* current = m_liveDecodedResources.m_head; current; current = current->m_nextInLiveResourcesList) { if (current == resource) { found = true; break; } } ASSERT(found); #endif CachedResource* next = resource->m_nextInLiveResourcesList; CachedResource* prev = resource->m_prevInLiveResourcesList; if (next == 0 && prev == 0 && m_liveDecodedResources.m_head != resource) return; resource->m_nextInLiveResourcesList = 0; resource->m_prevInLiveResourcesList = 0; if (next) next->m_prevInLiveResourcesList = prev; else if (m_liveDecodedResources.m_tail == resource) m_liveDecodedResources.m_tail = prev; if (prev) prev->m_nextInLiveResourcesList = next; else if (m_liveDecodedResources.m_head == resource) m_liveDecodedResources.m_head = next; } void Cache::insertInLiveDecodedResourcesList(CachedResource* resource) { // Make sure we aren't in the list already. ASSERT(!resource->m_nextInLiveResourcesList && !resource->m_prevInLiveResourcesList && !resource->m_inLiveDecodedResourcesList); resource->m_inLiveDecodedResourcesList = true; resource->m_nextInLiveResourcesList = m_liveDecodedResources.m_head; if (m_liveDecodedResources.m_head) m_liveDecodedResources.m_head->m_prevInLiveResourcesList = resource; m_liveDecodedResources.m_head = resource; if (!resource->m_nextInLiveResourcesList) m_liveDecodedResources.m_tail = resource; #ifndef NDEBUG // Verify that we are in now in the list like we should be. bool found = false; for (CachedResource* current = m_liveDecodedResources.m_head; current; current = current->m_nextInLiveResourcesList) { if (current == resource) { found = true; break; } } ASSERT(found); #endif } void Cache::addToLiveResourcesSize(CachedResource* resource) { m_liveSize += resource->size(); m_deadSize -= resource->size(); } void Cache::removeFromLiveResourcesSize(CachedResource* resource) { m_liveSize -= resource->size(); m_deadSize += resource->size(); } void Cache::adjustSize(bool live, int delta) { if (live) { ASSERT(delta >= 0 || ((int)m_liveSize + delta >= 0)); m_liveSize += delta; } else { ASSERT(delta >= 0 || ((int)m_deadSize + delta >= 0)); m_deadSize += delta; } } void Cache::TypeStatistic::addResource(CachedResource* o) { bool purged = o->wasPurged(); bool purgeable = o->isPurgeable() && !purged; int pageSize = (o->encodedSize() + o->overheadSize() + 4095) & ~4095; count++; size += purged ? 0 : o->size(); liveSize += o->hasClients() ? o->size() : 0; decodedSize += o->decodedSize(); purgeableSize += purgeable ? pageSize : 0; purgedSize += purged ? pageSize : 0; } Cache::Statistics Cache::getStatistics() { Statistics stats; CachedResourceMap::iterator e = m_resources.end(); for (CachedResourceMap::iterator i = m_resources.begin(); i != e; ++i) { CachedResource* resource = i->second; switch (resource->type()) { case CachedResource::ImageResource: stats.images.addResource(resource); break; case CachedResource::CSSStyleSheet: stats.cssStyleSheets.addResource(resource); break; case CachedResource::Script: stats.scripts.addResource(resource); break; #if ENABLE(XSLT) case CachedResource::XSLStyleSheet: stats.xslStyleSheets.addResource(resource); break; #endif case CachedResource::FontResource: stats.fonts.addResource(resource); break; #if ENABLE(XBL) case CachedResource::XBL: stats.xblDocs.addResource(resource) break; #endif default: break; } } return stats; } void Cache::setDisabled(bool disabled) { m_disabled = disabled; if (!m_disabled) return; for (;;) { CachedResourceMap::iterator i = m_resources.begin(); if (i == m_resources.end()) break; evict(i->second); } } #ifndef NDEBUG void Cache::dumpStats() { Statistics s = getStatistics(); printf("%-11s %-11s %-11s %-11s %-11s %-11s %-11s\n", "", "Count", "Size", "LiveSize", "DecodedSize", "PurgeableSize", "PurgedSize"); printf("%-11s %-11s %-11s %-11s %-11s %-11s %-11s\n", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------"); printf("%-11s %11d %11d %11d %11d %11d %11d\n", "Images", s.images.count, s.images.size, s.images.liveSize, s.images.decodedSize, s.images.purgeableSize, s.images.purgedSize); printf("%-11s %11d %11d %11d %11d %11d %11d\n", "CSS", s.cssStyleSheets.count, s.cssStyleSheets.size, s.cssStyleSheets.liveSize, s.cssStyleSheets.decodedSize, s.cssStyleSheets.purgeableSize, s.cssStyleSheets.purgedSize); #if ENABLE(XSLT) printf("%-11s %11d %11d %11d %11d %11d %11d\n", "XSL", s.xslStyleSheets.count, s.xslStyleSheets.size, s.xslStyleSheets.liveSize, s.xslStyleSheets.decodedSize, s.xslStyleSheets.purgeableSize, s.xslStyleSheets.purgedSize); #endif printf("%-11s %11d %11d %11d %11d %11d %11d\n", "JavaScript", s.scripts.count, s.scripts.size, s.scripts.liveSize, s.scripts.decodedSize, s.scripts.purgeableSize, s.scripts.purgedSize); printf("%-11s %11d %11d %11d %11d %11d %11d\n", "Fonts", s.fonts.count, s.fonts.size, s.fonts.liveSize, s.fonts.decodedSize, s.fonts.purgeableSize, s.fonts.purgedSize); printf("%-11s %-11s %-11s %-11s %-11s %-11s %-11s\n\n", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------"); } void Cache::dumpLRULists(bool includeLive) const { printf("LRU-SP lists in eviction order (Kilobytes decoded, Kilobytes encoded, Access count, Referenced):\n"); int size = m_allResources.size(); for (int i = size - 1; i >= 0; i--) { printf("\n\nList %d: ", i); CachedResource* current = m_allResources[i].m_tail; while (current) { CachedResource* prev = current->m_prevInAllResourcesList; if (includeLive || !current->hasClients()) printf("(%.1fK, %.1fK, %uA, %dR); ", current->decodedSize() / 1024.0f, (current->encodedSize() + current->overheadSize()) / 1024.0f, current->accessCount(), current->hasClients()); current = prev; } } } #endif } // namespace WebCore