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/*
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 "Cache.h"
#include "CachedResourceHandle.h"
#include "DocLoader.h"
#include "Frame.h"
#include "FrameLoader.h"
#include "KURL.h"
#include "PurgeableBuffer.h"
#include "Request.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 {
#ifndef NDEBUG
static RefCountedLeakCounter cachedResourceLeakCounter("CachedResource");
#endif
CachedResource::CachedResource(const String& url, Type type)
: m_url(url)
, m_responseTimestamp(currentTime())
, m_lastDecodedAccessTime(0)
, m_sendResourceLoadCallbacks(true)
, m_preloadCount(0)
, m_preloadResult(PreloadNotReferenced)
, m_requestedFromNetworkingLayer(false)
, m_inCache(false)
, m_loading(false)
, m_docLoader(0)
, m_handleCount(0)
, m_resourceToRevalidate(0)
, m_isBeingRevalidated(false)
{
#ifndef NDEBUG
cachedResourceLeakCounter.increment();
#endif
m_type = type;
m_status = Pending;
m_encodedSize = 0;
m_decodedSize = 0;
m_request = 0;
m_accessCount = 0;
m_inLiveDecodedResourcesList = false;
m_nextInAllResourcesList = 0;
m_prevInAllResourcesList = 0;
m_nextInLiveResourcesList = 0;
m_prevInLiveResourcesList = 0;
#ifndef NDEBUG
m_deleted = false;
m_lruIndex = 0;
#endif
m_errorOccurred = false;
}
CachedResource::~CachedResource()
{
ASSERT(!inCache());
ASSERT(!m_deleted);
ASSERT(url().isNull() || cache()->resourceForURL(url()) != this);
#ifndef NDEBUG
m_deleted = true;
cachedResourceLeakCounter.decrement();
#endif
if (m_resourceToRevalidate)
m_resourceToRevalidate->m_isBeingRevalidated = false;
if (m_docLoader)
m_docLoader->removeCachedResource(this);
}
void CachedResource::load(DocLoader* docLoader, bool incremental, bool skipCanLoadCheck, bool sendResourceLoadCallbacks)
{
m_sendResourceLoadCallbacks = sendResourceLoadCallbacks;
cache()->loader()->load(docLoader, this, incremental, skipCanLoadCheck, sendResourceLoadCallbacks);
m_loading = true;
}
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::setRequest(Request* request)
{
if (request && !m_request)
m_status = Pending;
m_request = request;
if (canDelete() && !inCache())
delete this;
}
void CachedResource::addClient(CachedResourceClient *c)
{
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())
cache()->addToLiveResourcesSize(this);
m_clients.add(c);
}
void CachedResource::removeClient(CachedResourceClient *c)
{
ASSERT(m_clients.contains(c));
m_clients.remove(c);
if (canDelete() && !inCache())
delete this;
else if (!hasClients() && inCache()) {
cache()->removeFromLiveResourcesSize(this);
cache()->removeFromLiveDecodedResourcesList(this);
allClientsRemoved();
cache()->prune();
}
}
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())
cache()->removeFromLRUList(this);
m_decodedSize = size;
if (inCache()) {
// Now insert into the new LRU list.
cache()->insertInLRUList(this);
// Insert into or remove from the live decoded list if necessary.
if (m_decodedSize && !m_inLiveDecodedResourcesList && hasClients())
cache()->insertInLiveDecodedResourcesList(this);
else if (!m_decodedSize && m_inLiveDecodedResourcesList)
cache()->removeFromLiveDecodedResourcesList(this);
// Update the cache's size totals.
cache()->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())
cache()->removeFromLRUList(this);
m_encodedSize = size;
if (inCache()) {
// Now insert into the new LRU list.
cache()->insertInLRUList(this);
// Update the cache's size totals.
cache()->adjustSize(hasClients(), delta);
}
}
void CachedResource::didAccessDecodedData(double timeStamp)
{
m_lastDecodedAccessTime = timeStamp;
if (inCache()) {
if (m_inLiveDecodedResourcesList) {
cache()->removeFromLiveDecodedResourcesList(this);
cache()->insertInLiveDecodedResourcesList(this);
}
cache()->prune();
}
}
void CachedResource::setResourceToRevalidate(CachedResource* resource)
{
ASSERT(resource);
ASSERT(!m_resourceToRevalidate);
ASSERT(resource != this);
ASSERT(!resource->m_isBeingRevalidated);
ASSERT(m_handlesToRevalidate.isEmpty());
ASSERT(resource->type() == type());
resource->m_isBeingRevalidated = true;
m_resourceToRevalidate = resource;
}
void CachedResource::clearResourceToRevalidate()
{
ASSERT(m_resourceToRevalidate);
m_resourceToRevalidate->m_isBeingRevalidated = false;
m_resourceToRevalidate->deleteIfPossible();
m_handlesToRevalidate.clear();
m_resourceToRevalidate = 0;
deleteIfPossible();
}
void CachedResource::switchClientsToRevalidatedResource()
{
ASSERT(m_resourceToRevalidate);
ASSERT(m_resourceToRevalidate->inCache());
ASSERT(!inCache());
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->addClient(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);
}
}
bool CachedResource::canUseCacheValidator() const
{
return !m_loading && (!m_response.httpHeaderField("Last-Modified").isEmpty() || !m_response.httpHeaderField("ETag").isEmpty());
}
bool CachedResource::mustRevalidate(CachePolicy cachePolicy) const
{
if (m_loading)
return false;
if (cachePolicy == CachePolicyCache)
return m_response.cacheControlContainsNoCache() || (isExpired() && m_response.cacheControlContainsMustRevalidate());
return isExpired() || m_response.cacheControlContainsNoCache();
}
bool CachedResource::isSafeToMakePurgeable() const
{
return !hasClients() && !m_isBeingRevalidated && !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 othen than this since we don't want two copies.
if (!m_data->hasOneRef())
return false;
// Purgeable buffers are allocated in multiples of the page size (4KB in common CPUs) so it does not make sense for very small buffers.
const size_t purgeableThreshold = 4 * 4096;
if (m_data->size() < purgeableThreshold)
return false;
if (m_data->hasPurgeableBuffer()) {
m_purgeableData.set(m_data->releasePurgeableBuffer());
} else {
m_purgeableData.set(PurgeableBuffer::create(m_data->data(), m_data->size()));
if (!m_purgeableData)
return false;
}
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
*/
}
}
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