/*
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) 2006 Samuel Weinig (sam.weinig@gmail.com)
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 "CachedResource.h"
#include "MemoryCache.h"
#include "CachedMetadata.h"
#include "CachedResourceClient.h"
#include "CachedResourceClientWalker.h"
#include "CachedResourceHandle.h"
#include "CachedResourceLoader.h"
#include "CachedResourceRequest.h"
#include "Frame.h"
#include "FrameLoaderClient.h"
#include "KURL.h"
#include "Logging.h"
#include "PurgeableBuffer.h"
#include "ResourceHandle.h"
#include "SharedBuffer.h"
#include <wtf/CurrentTime.h>
#include <wtf/MathExtras.h>
#include <wtf/RefCountedLeakCounter.h>
#include <wtf/StdLibExtras.h>
#include <wtf/Vector.h>
using namespace WTF;
namespace WebCore {
static ResourceLoadPriority defaultPriorityForResourceType(CachedResource::Type type)
{
switch (type) {
case CachedResource::CSSStyleSheet:
#if ENABLE(XSLT)
case CachedResource::XSLStyleSheet:
#endif
return ResourceLoadPriorityHigh;
case CachedResource::Script:
case CachedResource::FontResource:
return ResourceLoadPriorityMedium;
case CachedResource::ImageResource:
return ResourceLoadPriorityLow;
#if ENABLE(LINK_PREFETCH)
case CachedResource::LinkResource:
return ResourceLoadPriorityVeryLow;
#endif
}
ASSERT_NOT_REACHED();
return ResourceLoadPriorityLow;
}
#ifndef NDEBUG
static RefCountedLeakCounter cachedResourceLeakCounter("CachedResource");
#endif
CachedResource::CachedResource(const String& url, Type type)
: m_url(url)
, m_request(0)
, m_loadPriority(defaultPriorityForResourceType(type))
, m_responseTimestamp(currentTime())
, m_lastDecodedAccessTime(0)
, m_encodedSize(0)
, m_decodedSize(0)
, m_accessCount(0)
, m_handleCount(0)
, m_preloadCount(0)
, m_preloadResult(PreloadNotReferenced)
, m_inLiveDecodedResourcesList(false)
, m_requestedFromNetworkingLayer(false)
, m_sendResourceLoadCallbacks(true)
, m_inCache(false)
, m_loading(false)
, m_type(type)
, m_status(Pending)
#ifndef NDEBUG
, m_deleted(false)
, m_lruIndex(0)
#endif
, m_nextInAllResourcesList(0)
, m_prevInAllResourcesList(0)
, m_nextInLiveResourcesList(0)
, m_prevInLiveResourcesList(0)
, m_owningCachedResourceLoader(0)
, m_resourceToRevalidate(0)
, m_proxyResource(0)
{
#ifndef NDEBUG
cachedResourceLeakCounter.increment();
#endif
}
CachedResource::~CachedResource()
{
ASSERT(!m_resourceToRevalidate); // Should be true because canDelete() checks this.
ASSERT(canDelete());
ASSERT(!inCache());
ASSERT(!m_deleted);
ASSERT(url().isNull() || memoryCache()->resourceForURL(KURL(ParsedURLString, url())) != this);
#ifndef NDEBUG
m_deleted = true;
cachedResourceLeakCounter.decrement();
#endif
if (m_owningCachedResourceLoader)
m_owningCachedResourceLoader->removeCachedResource(this);
}
void CachedResource::load(CachedResourceLoader* cachedResourceLoader, bool incremental, SecurityCheckPolicy securityCheck, bool sendResourceLoadCallbacks)
{
m_sendResourceLoadCallbacks = sendResourceLoadCallbacks;
cachedResourceLoader->load(this, incremental, securityCheck, sendResourceLoadCallbacks);
m_loading = true;
}
void CachedResource::checkNotify()
{
if (isLoading())
return;
CachedResourceClientWalker w(m_clients);
while (CachedResourceClient* c = w.next())
c->notifyFinished(this);
}
void CachedResource::data(PassRefPtr<SharedBuffer>, bool allDataReceived)
{
if (!allDataReceived)
return;
setLoading(false);
checkNotify();
}
void CachedResource::error(CachedResource::Status status)
{
setStatus(status);
ASSERT(errorOccurred());
m_data.clear();
setLoading(false);
checkNotify();
}
void CachedResource::finish()
{
m_status = Cached;
}
bool CachedResource::isExpired() const
{
if (m_response.isNull())
return false;
return currentAge() > freshnessLifetime();
}
double CachedResource::currentAge() const
{
// RFC2616 13.2.3
// No compensation for latency as that is not terribly important in practice
double dateValue = m_response.date();
double apparentAge = isfinite(dateValue) ? max(0., m_responseTimestamp - dateValue) : 0;
double ageValue = m_response.age();
double correctedReceivedAge = isfinite(ageValue) ? max(apparentAge, ageValue) : apparentAge;
double residentTime = currentTime() - m_responseTimestamp;
return correctedReceivedAge + residentTime;
}
double CachedResource::freshnessLifetime() const
{
// Cache non-http resources liberally
if (!m_response.url().protocolInHTTPFamily())
return std::numeric_limits<double>::max();
// RFC2616 13.2.4
double maxAgeValue = m_response.cacheControlMaxAge();
if (isfinite(maxAgeValue))
return maxAgeValue;
double expiresValue = m_response.expires();
double dateValue = m_response.date();
double creationTime = isfinite(dateValue) ? dateValue : m_responseTimestamp;
if (isfinite(expiresValue))
return expiresValue - creationTime;
double lastModifiedValue = m_response.lastModified();
if (isfinite(lastModifiedValue))
return (creationTime - lastModifiedValue) * 0.1;
// If no cache headers are present, the specification leaves the decision to the UA. Other browsers seem to opt for 0.
return 0;
}
void CachedResource::setResponse(const ResourceResponse& response)
{
m_response = response;
m_responseTimestamp = currentTime();
}
void CachedResource::setSerializedCachedMetadata(const char* data, size_t size)
{
// We only expect to receive cached metadata from the platform once.
// If this triggers, it indicates an efficiency problem which is most
// likely unexpected in code designed to improve performance.
ASSERT(!m_cachedMetadata);
m_cachedMetadata = CachedMetadata::deserialize(data, size);
}
void CachedResource::setCachedMetadata(unsigned dataTypeID, const char* data, size_t size)
{
// Currently, only one type of cached metadata per resource is supported.
// If the need arises for multiple types of metadata per resource this could
// be enhanced to store types of metadata in a map.
ASSERT(!m_cachedMetadata);
m_cachedMetadata = CachedMetadata::create(dataTypeID, data, size);
ResourceHandle::cacheMetadata(m_response, m_cachedMetadata->serialize());
}
CachedMetadata* CachedResource::cachedMetadata(unsigned dataTypeID) const
{
if (!m_cachedMetadata || m_cachedMetadata->dataTypeID() != dataTypeID)
return 0;
return m_cachedMetadata.get();
}
void CachedResource::setRequest(CachedResourceRequest* request)
{
if (request && !m_request)
m_status = Pending;
m_request = request;
if (canDelete() && !inCache())
delete this;
}
void CachedResource::addClient(CachedResourceClient* client)
{
addClientToSet(client);
didAddClient(client);
}
void CachedResource::didAddClient(CachedResourceClient* c)
{
if (!isLoading())
c->notifyFinished(this);
}
void CachedResource::addClientToSet(CachedResourceClient* client)
{
ASSERT(!isPurgeable());
if (m_preloadResult == PreloadNotReferenced) {
if (isLoaded())
m_preloadResult = PreloadReferencedWhileComplete;
else if (m_requestedFromNetworkingLayer)
m_preloadResult = PreloadReferencedWhileLoading;
else
m_preloadResult = PreloadReferenced;
}
if (!hasClients() && inCache())
memoryCache()->addToLiveResourcesSize(this);
m_clients.add(client);
}
void CachedResource::removeClient(CachedResourceClient* client)
{
ASSERT(m_clients.contains(client));
m_clients.remove(client);
if (canDelete() && !inCache())
delete this;
else if (!hasClients() && inCache()) {
memoryCache()->removeFromLiveResourcesSize(this);
memoryCache()->removeFromLiveDecodedResourcesList(this);
allClientsRemoved();
if (response().cacheControlContainsNoStore()) {
// RFC2616 14.9.2:
// "no-store: ... MUST make a best-effort attempt to remove the information from volatile storage as promptly as possible"
// "... History buffers MAY store such responses as part of their normal operation."
// We allow non-secure content to be reused in history, but we do not allow secure content to be reused.
if (protocolIs(url(), "https"))
memoryCache()->remove(this);
} else
memoryCache()->prune();
}
// This object may be dead here.
}
void CachedResource::deleteIfPossible()
{
if (canDelete() && !inCache())
delete this;
}
void CachedResource::setDecodedSize(unsigned size)
{
if (size == m_decodedSize)
return;
int delta = size - m_decodedSize;
// The object must now be moved to a different queue, since its size has been changed.
// We have to remove explicitly before updating m_decodedSize, so that we find the correct previous
// queue.
if (inCache())
memoryCache()->removeFromLRUList(this);
m_decodedSize = size;
if (inCache()) {
// Now insert into the new LRU list.
memoryCache()->insertInLRUList(this);
// Insert into or remove from the live decoded list if necessary.
// When inserting into the LiveDecodedResourcesList it is possible
// that the m_lastDecodedAccessTime is still zero or smaller than
// the m_lastDecodedAccessTime of the current list head. This is a
// violation of the invariant that the list is to be kept sorted
// by access time. The weakening of the invariant does not pose
// a problem. For more details please see: https://bugs.webkit.org/show_bug.cgi?id=30209
if (m_decodedSize && !m_inLiveDecodedResourcesList && hasClients())
memoryCache()->insertInLiveDecodedResourcesList(this);
else if (!m_decodedSize && m_inLiveDecodedResourcesList)
memoryCache()->removeFromLiveDecodedResourcesList(this);
// Update the cache's size totals.
memoryCache()->adjustSize(hasClients(), delta);
}
}
void CachedResource::setEncodedSize(unsigned size)
{
if (size == m_encodedSize)
return;
// The size cannot ever shrink (unless it is being nulled out because of an error). If it ever does, assert.
ASSERT(size == 0 || size >= m_encodedSize);
int delta = size - m_encodedSize;
// The object must now be moved to a different queue, since its size has been changed.
// We have to remove explicitly before updating m_encodedSize, so that we find the correct previous
// queue.
if (inCache())
memoryCache()->removeFromLRUList(this);
m_encodedSize = size;
if (inCache()) {
// Now insert into the new LRU list.
memoryCache()->insertInLRUList(this);
// Update the cache's size totals.
memoryCache()->adjustSize(hasClients(), delta);
}
}
void CachedResource::didAccessDecodedData(double timeStamp)
{
m_lastDecodedAccessTime = timeStamp;
if (inCache()) {
if (m_inLiveDecodedResourcesList) {
memoryCache()->removeFromLiveDecodedResourcesList(this);
memoryCache()->insertInLiveDecodedResourcesList(this);
}
memoryCache()->prune();
}
}
void CachedResource::setResourceToRevalidate(CachedResource* resource)
{
ASSERT(resource);
ASSERT(!m_resourceToRevalidate);
ASSERT(resource != this);
ASSERT(m_handlesToRevalidate.isEmpty());
ASSERT(resource->type() == type());
LOG(ResourceLoading, "CachedResource %p setResourceToRevalidate %p", this, resource);
// The following assert should be investigated whenever it occurs. Although it should never fire, it currently does in rare circumstances.
// https://bugs.webkit.org/show_bug.cgi?id=28604.
// So the code needs to be robust to this assert failing thus the "if (m_resourceToRevalidate->m_proxyResource == this)" in CachedResource::clearResourceToRevalidate.
ASSERT(!resource->m_proxyResource);
resource->m_proxyResource = this;
m_resourceToRevalidate = resource;
}
void CachedResource::clearResourceToRevalidate()
{
ASSERT(m_resourceToRevalidate);
// A resource may start revalidation before this method has been called, so check that this resource is still the proxy resource before clearing it out.
if (m_resourceToRevalidate->m_proxyResource == this) {
m_resourceToRevalidate->m_proxyResource = 0;
m_resourceToRevalidate->deleteIfPossible();
}
m_handlesToRevalidate.clear();
m_resourceToRevalidate = 0;
deleteIfPossible();
}
void CachedResource::switchClientsToRevalidatedResource()
{
ASSERT(m_resourceToRevalidate);
ASSERT(m_resourceToRevalidate->inCache());
ASSERT(!inCache());
LOG(ResourceLoading, "CachedResource %p switchClientsToRevalidatedResource %p", this, m_resourceToRevalidate);
HashSet<CachedResourceHandleBase*>::iterator end = m_handlesToRevalidate.end();
for (HashSet<CachedResourceHandleBase*>::iterator it = m_handlesToRevalidate.begin(); it != end; ++it) {
CachedResourceHandleBase* handle = *it;
handle->m_resource = m_resourceToRevalidate;
m_resourceToRevalidate->registerHandle(handle);
--m_handleCount;
}
ASSERT(!m_handleCount);
m_handlesToRevalidate.clear();
Vector<CachedResourceClient*> clientsToMove;
HashCountedSet<CachedResourceClient*>::iterator end2 = m_clients.end();
for (HashCountedSet<CachedResourceClient*>::iterator it = m_clients.begin(); it != end2; ++it) {
CachedResourceClient* client = it->first;
unsigned count = it->second;
while (count) {
clientsToMove.append(client);
--count;
}
}
// Equivalent of calling removeClient() for all clients
m_clients.clear();
unsigned moveCount = clientsToMove.size();
for (unsigned n = 0; n < moveCount; ++n)
m_resourceToRevalidate->addClientToSet(clientsToMove[n]);
for (unsigned n = 0; n < moveCount; ++n) {
// Calling didAddClient for a client may end up removing another client. In that case it won't be in the set anymore.
if (m_resourceToRevalidate->m_clients.contains(clientsToMove[n]))
m_resourceToRevalidate->didAddClient(clientsToMove[n]);
}
}
void CachedResource::updateResponseAfterRevalidation(const ResourceResponse& validatingResponse)
{
m_responseTimestamp = currentTime();
DEFINE_STATIC_LOCAL(const AtomicString, contentHeaderPrefix, ("content-"));
// RFC2616 10.3.5
// Update cached headers from the 304 response
const HTTPHeaderMap& newHeaders = validatingResponse.httpHeaderFields();
HTTPHeaderMap::const_iterator end = newHeaders.end();
for (HTTPHeaderMap::const_iterator it = newHeaders.begin(); it != end; ++it) {
// Don't allow 304 response to update content headers, these can't change but some servers send wrong values.
if (it->first.startsWith(contentHeaderPrefix, false))
continue;
m_response.setHTTPHeaderField(it->first, it->second);
}
}
void CachedResource::registerHandle(CachedResourceHandleBase* h)
{
++m_handleCount;
if (m_resourceToRevalidate)
m_handlesToRevalidate.add(h);
}
void CachedResource::unregisterHandle(CachedResourceHandleBase* h)
{
ASSERT(m_handleCount > 0);
--m_handleCount;
if (m_resourceToRevalidate)
m_handlesToRevalidate.remove(h);
if (!m_handleCount)
deleteIfPossible();
}
bool CachedResource::canUseCacheValidator() const
{
if (m_loading || errorOccurred())
return false;
if (m_response.cacheControlContainsNoStore())
return false;
return m_response.hasCacheValidatorFields();
}
bool CachedResource::mustRevalidateDueToCacheHeaders(CachePolicy cachePolicy) const
{
ASSERT(cachePolicy == CachePolicyRevalidate || cachePolicy == CachePolicyCache || cachePolicy == CachePolicyVerify);
if (cachePolicy == CachePolicyRevalidate)
return true;
if (m_response.cacheControlContainsNoCache() || m_response.cacheControlContainsNoStore()) {
LOG(ResourceLoading, "CachedResource %p mustRevalidate because of m_response.cacheControlContainsNoCache() || m_response.cacheControlContainsNoStore()\n", this);
return true;
}
if (cachePolicy == CachePolicyCache) {
if (m_response.cacheControlContainsMustRevalidate() && isExpired()) {
LOG(ResourceLoading, "CachedResource %p mustRevalidate because of cachePolicy == CachePolicyCache and m_response.cacheControlContainsMustRevalidate() && isExpired()\n", this);
return true;
}
return false;
}
// CachePolicyVerify
if (isExpired()) {
LOG(ResourceLoading, "CachedResource %p mustRevalidate because of isExpired()\n", this);
return true;
}
return false;
}
bool CachedResource::isSafeToMakePurgeable() const
{
return !hasClients() && !m_proxyResource && !m_resourceToRevalidate;
}
bool CachedResource::makePurgeable(bool purgeable)
{
if (purgeable) {
ASSERT(isSafeToMakePurgeable());
if (m_purgeableData) {
ASSERT(!m_data);
return true;
}
if (!m_data)
return false;
// Should not make buffer purgeable if it has refs other than this since we don't want two copies.
if (!m_data->hasOneRef())
return false;
if (m_data->hasPurgeableBuffer()) {
m_purgeableData = m_data->releasePurgeableBuffer();
} else {
m_purgeableData = PurgeableBuffer::create(m_data->data(), m_data->size());
if (!m_purgeableData)
return false;
m_purgeableData->setPurgePriority(purgePriority());
}
m_purgeableData->makePurgeable(true);
m_data.clear();
return true;
}
if (!m_purgeableData)
return true;
ASSERT(!m_data);
ASSERT(!hasClients());
if (!m_purgeableData->makePurgeable(false))
return false;
m_data = SharedBuffer::adoptPurgeableBuffer(m_purgeableData.release());
return true;
}
bool CachedResource::isPurgeable() const
{
return m_purgeableData && m_purgeableData->isPurgeable();
}
bool CachedResource::wasPurged() const
{
return m_purgeableData && m_purgeableData->wasPurged();
}
unsigned CachedResource::overheadSize() const
{
return sizeof(CachedResource) + m_response.memoryUsage() + 576;
/*
576 = 192 + // average size of m_url
384; // average size of m_clients hash map
*/
}
void CachedResource::setLoadPriority(ResourceLoadPriority loadPriority)
{
if (loadPriority == ResourceLoadPriorityUnresolved)
return;
m_loadPriority = loadPriority;
}
}