0567d1d5de8c6f13e186844aed75575cf17e172f
[WebKit-https.git] / Source / WebCore / loader / cache / CachedResource.cpp
1 /*
2     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
3     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
4     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
5     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
6     Copyright (C) 2004-2011, 2014, 2018 Apple Inc. All rights reserved.
7
8     This library is free software; you can redistribute it and/or
9     modify it under the terms of the GNU Library General Public
10     License as published by the Free Software Foundation; either
11     version 2 of the License, or (at your option) any later version.
12
13     This library is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16     Library General Public License for more details.
17
18     You should have received a copy of the GNU Library General Public License
19     along with this library; see the file COPYING.LIB.  If not, write to
20     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21     Boston, MA 02110-1301, USA.
22 */
23
24 #include "config.h"
25 #include "CachedResource.h"
26
27 #include "CachedResourceClient.h"
28 #include "CachedResourceClientWalker.h"
29 #include "CachedResourceHandle.h"
30 #include "CachedResourceLoader.h"
31 #include "CookieJar.h"
32 #include "CrossOriginAccessControl.h"
33 #include "DiagnosticLoggingClient.h"
34 #include "DiagnosticLoggingKeys.h"
35 #include "Document.h"
36 #include "DocumentLoader.h"
37 #include "Frame.h"
38 #include "FrameLoader.h"
39 #include "FrameLoaderClient.h"
40 #include "HTTPHeaderNames.h"
41 #include "InspectorInstrumentation.h"
42 #include "LoaderStrategy.h"
43 #include "Logging.h"
44 #include "MemoryCache.h"
45 #include "PlatformStrategies.h"
46 #include "ProgressTracker.h"
47 #include "ResourceHandle.h"
48 #include "SchemeRegistry.h"
49 #include "SecurityOrigin.h"
50 #include "SubresourceLoader.h"
51 #include <wtf/CompletionHandler.h>
52 #include <wtf/MathExtras.h>
53 #include <wtf/RefCountedLeakCounter.h>
54 #include <wtf/StdLibExtras.h>
55 #include <wtf/URL.h>
56 #include <wtf/Vector.h>
57 #include <wtf/text/CString.h>
58
59 #if USE(QUICK_LOOK)
60 #include "QuickLook.h"
61 #endif
62
63 #define RELEASE_LOG_IF_ALLOWED(fmt, ...) RELEASE_LOG_IF(cachedResourceLoader.isAlwaysOnLoggingAllowed(), Network, "%p - CachedResource::" fmt, this, ##__VA_ARGS__)
64
65 namespace WebCore {
66
67 ResourceLoadPriority CachedResource::defaultPriorityForResourceType(Type type)
68 {
69     switch (type) {
70     case Type::MainResource:
71         return ResourceLoadPriority::VeryHigh;
72     case Type::CSSStyleSheet:
73     case Type::Script:
74         return ResourceLoadPriority::High;
75 #if ENABLE(SVG_FONTS)
76     case Type::SVGFontResource:
77 #endif
78     case Type::MediaResource:
79     case Type::FontResource:
80     case Type::RawResource:
81     case Type::Icon:
82         return ResourceLoadPriority::Medium;
83     case Type::ImageResource:
84         return ResourceLoadPriority::Low;
85 #if ENABLE(XSLT)
86     case Type::XSLStyleSheet:
87         return ResourceLoadPriority::High;
88 #endif
89     case Type::SVGDocumentResource:
90         return ResourceLoadPriority::Low;
91     case Type::Beacon:
92     case Type::Ping:
93         return ResourceLoadPriority::VeryLow;
94     case Type::LinkPrefetch:
95         return ResourceLoadPriority::VeryLow;
96 #if ENABLE(VIDEO_TRACK)
97     case Type::TextTrackResource:
98         return ResourceLoadPriority::Low;
99 #endif
100 #if ENABLE(APPLICATION_MANIFEST)
101     case Type::ApplicationManifest:
102         return ResourceLoadPriority::Low;
103 #endif
104     }
105     ASSERT_NOT_REACHED();
106     return ResourceLoadPriority::Low;
107 }
108
109 static Seconds deadDecodedDataDeletionIntervalForResourceType(CachedResource::Type type)
110 {
111     if (type == CachedResource::Type::Script)
112         return 0_s;
113
114     return MemoryCache::singleton().deadDecodedDataDeletionInterval();
115 }
116
117 DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, cachedResourceLeakCounter, ("CachedResource"));
118
119 CachedResource::CachedResource(CachedResourceRequest&& request, Type type, const PAL::SessionID& sessionID, const CookieJar* cookieJar)
120     : m_options(request.options())
121     , m_resourceRequest(request.releaseResourceRequest())
122     , m_decodedDataDeletionTimer(*this, &CachedResource::destroyDecodedData, deadDecodedDataDeletionIntervalForResourceType(type))
123     , m_sessionID(sessionID)
124     , m_cookieJar(cookieJar)
125     , m_responseTimestamp(WallTime::now())
126     , m_fragmentIdentifierForRequest(request.releaseFragmentIdentifier())
127     , m_origin(request.releaseOrigin())
128     , m_initiatorName(request.initiatorName())
129     , m_loadPriority(defaultPriorityForResourceType(type))
130     , m_type(type)
131     , m_isLinkPreload(request.isLinkPreload())
132     , m_hasUnknownEncoding(request.isLinkPreload())
133     , m_ignoreForRequestCount(request.ignoreForRequestCount())
134 {
135     ASSERT(m_sessionID.isValid());
136
137     setLoadPriority(request.priority());
138 #ifndef NDEBUG
139     cachedResourceLeakCounter.increment();
140 #endif
141
142     // FIXME: We should have a better way of checking for Navigation loads, maybe FetchMode::Options::Navigate.
143     ASSERT(m_origin || m_type == Type::MainResource);
144
145     if (isRequestCrossOrigin(m_origin.get(), m_resourceRequest.url(), m_options))
146         setCrossOrigin();
147 }
148
149 // FIXME: For this constructor, we should probably mandate that the URL has no fragment identifier.
150 CachedResource::CachedResource(const URL& url, Type type, const PAL::SessionID& sessionID, const CookieJar* cookieJar)
151     : m_resourceRequest(url)
152     , m_decodedDataDeletionTimer(*this, &CachedResource::destroyDecodedData, deadDecodedDataDeletionIntervalForResourceType(type))
153     , m_sessionID(sessionID)
154     , m_cookieJar(cookieJar)
155     , m_responseTimestamp(WallTime::now())
156     , m_fragmentIdentifierForRequest(CachedResourceRequest::splitFragmentIdentifierFromRequestURL(m_resourceRequest))
157     , m_status(Cached)
158     , m_type(type)
159 {
160     ASSERT(m_sessionID.isValid());
161 #ifndef NDEBUG
162     cachedResourceLeakCounter.increment();
163 #endif
164 }
165
166 CachedResource::~CachedResource()
167 {
168     ASSERT(!m_resourceToRevalidate); // Should be true because canDelete() checks this.
169     ASSERT(canDelete());
170     ASSERT(!inCache());
171     ASSERT(!m_deleted);
172     ASSERT(url().isNull() || !allowsCaching() || MemoryCache::singleton().resourceForRequest(resourceRequest(), sessionID()) != this);
173
174 #ifndef NDEBUG
175     m_deleted = true;
176     cachedResourceLeakCounter.decrement();
177 #endif
178 }
179
180 void CachedResource::failBeforeStarting()
181 {
182     // FIXME: What if resources in other frames were waiting for this revalidation?
183     LOG(ResourceLoading, "Cannot start loading '%s'", url().string().latin1().data());
184     if (allowsCaching() && m_resourceToRevalidate)
185         MemoryCache::singleton().revalidationFailed(*this);
186     error(CachedResource::LoadError);
187 }
188
189 void CachedResource::load(CachedResourceLoader& cachedResourceLoader)
190 {
191     if (!cachedResourceLoader.frame()) {
192         RELEASE_LOG_IF_ALLOWED("load: No associated frame");
193         failBeforeStarting();
194         return;
195     }
196     Frame& frame = *cachedResourceLoader.frame();
197
198     // Prevent new loads if we are in the PageCache or being added to the PageCache.
199     // We query the top document because new frames may be created in pagehide event handlers
200     // and their pageCacheState will not reflect the fact that they are about to enter page
201     // cache.
202     if (auto* topDocument = frame.mainFrame().document()) {
203         switch (topDocument->pageCacheState()) {
204         case Document::NotInPageCache:
205             break;
206         case Document::AboutToEnterPageCache:
207             // Beacons are allowed to go through in 'pagehide' event handlers.
208             if (shouldUsePingLoad(type()))
209                 break;
210             RELEASE_LOG_IF_ALLOWED("load: About to enter page cache (frame = %p)", &frame);
211             failBeforeStarting();
212             return;
213         case Document::InPageCache:
214             RELEASE_LOG_IF_ALLOWED("load: Already in page cache (frame = %p)", &frame);
215             failBeforeStarting();
216             return;
217         }
218     }
219
220     FrameLoader& frameLoader = frame.loader();
221     if (m_options.securityCheck == SecurityCheckPolicy::DoSecurityCheck && !shouldUsePingLoad(type())) {
222         while (true) {
223             if (frameLoader.state() == FrameStateProvisional)
224                 RELEASE_LOG_IF_ALLOWED("load: Failed security check -- state is provisional (frame = %p)", &frame);
225             else if (!frameLoader.activeDocumentLoader())
226                 RELEASE_LOG_IF_ALLOWED("load: Failed security check -- not active document (frame = %p)", &frame);
227             else if (frameLoader.activeDocumentLoader()->isStopping())
228                 RELEASE_LOG_IF_ALLOWED("load: Failed security check -- active loader is stopping (frame = %p)", &frame);
229             else
230                 break;
231             failBeforeStarting();
232             return;
233         }
234     }
235
236     m_loading = true;
237
238     if (isCacheValidator()) {
239         CachedResource* resourceToRevalidate = m_resourceToRevalidate;
240         ASSERT(resourceToRevalidate->canUseCacheValidator());
241         ASSERT(resourceToRevalidate->isLoaded());
242         const String& lastModified = resourceToRevalidate->response().httpHeaderField(HTTPHeaderName::LastModified);
243         const String& eTag = resourceToRevalidate->response().httpHeaderField(HTTPHeaderName::ETag);
244         if (!lastModified.isEmpty() || !eTag.isEmpty()) {
245             ASSERT(cachedResourceLoader.cachePolicy(type(), url()) != CachePolicyReload);
246             if (cachedResourceLoader.cachePolicy(type(), url()) == CachePolicyRevalidate)
247                 m_resourceRequest.setHTTPHeaderField(HTTPHeaderName::CacheControl, "max-age=0");
248             if (!lastModified.isEmpty())
249                 m_resourceRequest.setHTTPHeaderField(HTTPHeaderName::IfModifiedSince, lastModified);
250             if (!eTag.isEmpty())
251                 m_resourceRequest.setHTTPHeaderField(HTTPHeaderName::IfNoneMatch, eTag);
252         }
253     }
254
255     if (type() == Type::LinkPrefetch)
256         m_resourceRequest.setHTTPHeaderField(HTTPHeaderName::Purpose, "prefetch");
257     m_resourceRequest.setPriority(loadPriority());
258
259     // Navigation algorithm is setting up the request before sending it to CachedResourceLoader?CachedResource.
260     // So no need for extra fields for MainResource.
261     if (type() != Type::MainResource)
262         frameLoader.addExtraFieldsToSubresourceRequest(m_resourceRequest);
263
264
265     // FIXME: It's unfortunate that the cache layer and below get to know anything about fragment identifiers.
266     // We should look into removing the expectation of that knowledge from the platform network stacks.
267     ResourceRequest request(m_resourceRequest);
268     if (!m_fragmentIdentifierForRequest.isNull()) {
269         URL url = request.url();
270         url.setFragmentIdentifier(m_fragmentIdentifierForRequest);
271         request.setURL(url);
272         m_fragmentIdentifierForRequest = String();
273     }
274
275     if (m_options.keepAlive && type() != Type::Ping && !cachedResourceLoader.keepaliveRequestTracker().tryRegisterRequest(*this)) {
276         setResourceError({ errorDomainWebKitInternal, 0, request.url(), "Reached maximum amount of queued data of 64Kb for keepalive requests"_s, ResourceError::Type::AccessControl });
277         failBeforeStarting();
278         return;
279     }
280
281     // FIXME: Deprecate that code path.
282     if (m_options.keepAlive && shouldUsePingLoad(type()) && platformStrategies()->loaderStrategy()->usePingLoad()) {
283         ASSERT(m_originalRequest);
284         CachedResourceHandle<CachedResource> protectedThis(this);
285
286         unsigned long identifier = frame.page()->progress().createUniqueIdentifier();
287         InspectorInstrumentation::willSendRequestOfType(&frame, identifier, frameLoader.activeDocumentLoader(), request, InspectorInstrumentation::LoadType::Beacon);
288
289         platformStrategies()->loaderStrategy()->startPingLoad(frame, request, m_originalRequest->httpHeaderFields(), m_options, m_options.contentSecurityPolicyImposition, [this, protectedThis = WTFMove(protectedThis), protectedFrame = makeRef(frame), identifier] (const ResourceError& error, const ResourceResponse& response) {
290             if (!response.isNull())
291                 InspectorInstrumentation::didReceiveResourceResponse(protectedFrame, identifier, protectedFrame->loader().activeDocumentLoader(), response, nullptr);
292             if (!error.isNull()) {
293                 setResourceError(error);
294                 this->error(LoadError);
295                 InspectorInstrumentation::didFailLoading(protectedFrame.ptr(), protectedFrame->loader().activeDocumentLoader(), identifier, error);
296                 return;
297             }
298             finishLoading(nullptr);
299             NetworkLoadMetrics emptyMetrics;
300             InspectorInstrumentation::didFinishLoading(protectedFrame.ptr(), protectedFrame->loader().activeDocumentLoader(), identifier, emptyMetrics, nullptr);
301         });
302         return;
303     }
304
305     platformStrategies()->loaderStrategy()->loadResource(frame, *this, WTFMove(request), m_options, [this, protectedThis = CachedResourceHandle<CachedResource>(this), frame = makeRef(frame), loggingAllowed = cachedResourceLoader.isAlwaysOnLoggingAllowed()] (RefPtr<SubresourceLoader>&& loader) {
306         m_loader = WTFMove(loader);
307         if (!m_loader) {
308             RELEASE_LOG_IF(loggingAllowed, Network, "%p - CachedResource::load: Unable to create SubresourceLoader (frame = %p)", this, frame.ptr());
309             failBeforeStarting();
310             return;
311         }
312         m_status = Pending;
313     });
314 }
315
316 void CachedResource::loadFrom(const CachedResource& resource)
317 {
318     ASSERT(url() == resource.url());
319     ASSERT(type() == resource.type());
320     ASSERT(resource.status() == Status::Cached);
321
322     if (isCrossOrigin() && m_options.mode == FetchOptions::Mode::Cors) {
323         ASSERT(m_origin);
324         String errorMessage;
325         if (!WebCore::passesAccessControlCheck(resource.response(), m_options.storedCredentialsPolicy, *m_origin, errorMessage)) {
326             setResourceError(ResourceError(String(), 0, url(), errorMessage, ResourceError::Type::AccessControl));
327             return;
328         }
329     }
330
331     setBodyDataFrom(resource);
332     setStatus(Status::Cached);
333     setLoading(false);
334 }
335
336 void CachedResource::setBodyDataFrom(const CachedResource& resource)
337 {
338     m_data = resource.m_data;
339     m_response = resource.m_response;
340     m_response.setTainting(m_responseTainting);
341     setDecodedSize(resource.decodedSize());
342     setEncodedSize(resource.encodedSize());
343 }
344
345 void CachedResource::checkNotify()
346 {
347     if (isLoading() || stillNeedsLoad())
348         return;
349
350     CachedResourceClientWalker<CachedResourceClient> walker(m_clients);
351     while (CachedResourceClient* client = walker.next())
352         client->notifyFinished(*this);
353 }
354
355 void CachedResource::updateBuffer(SharedBuffer&)
356 {
357     ASSERT(dataBufferingPolicy() == DataBufferingPolicy::BufferData);
358 }
359
360 void CachedResource::updateData(const char*, unsigned)
361 {
362     ASSERT(dataBufferingPolicy() == DataBufferingPolicy::DoNotBufferData);
363 }
364
365 void CachedResource::finishLoading(SharedBuffer*)
366 {
367     setLoading(false);
368     checkNotify();
369 }
370
371 void CachedResource::error(CachedResource::Status status)
372 {
373     setStatus(status);
374     ASSERT(errorOccurred());
375     m_data = nullptr;
376
377     setLoading(false);
378     checkNotify();
379 }
380     
381 void CachedResource::cancelLoad()
382 {
383     if (!isLoading() && !stillNeedsLoad())
384         return;
385
386     auto* documentLoader = (m_loader && m_loader->frame()) ? m_loader->frame()->loader().activeDocumentLoader() : nullptr;
387     if (m_options.keepAlive && (!documentLoader || documentLoader->isStopping()))
388         m_error = { };
389     else
390         setStatus(LoadError);
391
392     setLoading(false);
393     checkNotify();
394 }
395
396 void CachedResource::finish()
397 {
398     if (!errorOccurred())
399         m_status = Cached;
400 }
401
402 void CachedResource::setCrossOrigin()
403 {
404     ASSERT(m_options.mode != FetchOptions::Mode::SameOrigin);
405     m_responseTainting = (m_options.mode == FetchOptions::Mode::Cors) ? ResourceResponse::Tainting::Cors : ResourceResponse::Tainting::Opaque;
406 }
407
408 bool CachedResource::isCrossOrigin() const
409 {
410     return m_responseTainting != ResourceResponse::Tainting::Basic;
411 }
412
413 bool CachedResource::isCORSSameOrigin() const
414 {
415     // Following resource types do not use CORS
416     ASSERT(type() != Type::FontResource);
417 #if ENABLE(SVG_FONTS)
418     ASSERT(type() != Type::SVGFontResource);
419 #endif
420 #if ENABLE(XSLT)
421     ASSERT(type() != Type::XSLStyleSheet);
422 #endif
423
424     // https://html.spec.whatwg.org/multipage/infrastructure.html#cors-same-origin
425     return !loadFailedOrCanceled() && m_responseTainting != ResourceResponse::Tainting::Opaque;
426 }
427
428 bool CachedResource::isExpired() const
429 {
430     if (m_response.isNull())
431         return false;
432
433     return computeCurrentAge(m_response, m_responseTimestamp) > freshnessLifetime(m_response);
434 }
435
436 static inline bool shouldCacheSchemeIndefinitely(StringView scheme)
437 {
438 #if PLATFORM(COCOA)
439     if (equalLettersIgnoringASCIICase(scheme, "applewebdata"))
440         return true;
441 #endif
442 #if USE(SOUP)
443     if (equalLettersIgnoringASCIICase(scheme, "resource"))
444         return true;
445 #endif
446     return equalLettersIgnoringASCIICase(scheme, "data");
447 }
448
449 Seconds CachedResource::freshnessLifetime(const ResourceResponse& response) const
450 {
451     if (!response.url().protocolIsInHTTPFamily()) {
452         StringView protocol = response.url().protocol();
453         if (!shouldCacheSchemeIndefinitely(protocol)) {
454             // Don't cache non-HTTP main resources since we can't check for freshness.
455             // FIXME: We should not cache subresources either, but when we tried this
456             // it caused performance and flakiness issues in our test infrastructure.
457             if (m_type == Type::MainResource || SchemeRegistry::shouldAlwaysRevalidateURLScheme(protocol.toStringWithoutCopying()))
458                 return 0_us;
459         }
460
461         return Seconds::infinity();
462     }
463
464     return computeFreshnessLifetimeForHTTPFamily(response, m_responseTimestamp);
465 }
466
467 void CachedResource::redirectReceived(ResourceRequest&& request, const ResourceResponse& response, CompletionHandler<void(ResourceRequest&&)>&& completionHandler)
468 {
469     m_requestedFromNetworkingLayer = true;
470     if (response.isNull())
471         return completionHandler(WTFMove(request));
472
473     updateRedirectChainStatus(m_redirectChainCacheStatus, response);
474     completionHandler(WTFMove(request));
475 }
476
477 void CachedResource::setResponse(const ResourceResponse& response)
478 {
479     ASSERT(m_response.type() == ResourceResponse::Type::Default);
480     m_response = response;
481     m_varyingHeaderValues = collectVaryingRequestHeaders(cookieJar(), m_resourceRequest, m_response, sessionID());
482
483 #if ENABLE(SERVICE_WORKER)
484     if (m_response.source() == ResourceResponse::Source::ServiceWorker) {
485         m_responseTainting = m_response.tainting();
486         return;
487     }
488 #endif
489     m_response.setRedirected(m_redirectChainCacheStatus.status != RedirectChainCacheStatus::Status::NoRedirection);
490     if (m_response.tainting() == ResourceResponse::Tainting::Basic || m_response.tainting() == ResourceResponse::Tainting::Cors)
491         m_response.setTainting(m_responseTainting);
492 }
493
494 void CachedResource::responseReceived(const ResourceResponse& response)
495 {
496     setResponse(response);
497     m_responseTimestamp = WallTime::now();
498     String encoding = response.textEncodingName();
499     if (!encoding.isNull())
500         setEncoding(encoding);
501 }
502
503 void CachedResource::clearLoader()
504 {
505     ASSERT(m_loader);
506     m_identifierForLoadWithoutResourceLoader = m_loader->identifier();
507     m_loader = nullptr;
508     deleteIfPossible();
509 }
510
511 void CachedResource::addClient(CachedResourceClient& client)
512 {
513     if (addClientToSet(client))
514         didAddClient(client);
515 }
516
517 void CachedResource::didAddClient(CachedResourceClient& client)
518 {
519     if (m_decodedDataDeletionTimer.isActive())
520         m_decodedDataDeletionTimer.stop();
521
522     if (m_clientsAwaitingCallback.remove(&client))
523         m_clients.add(&client);
524
525     // FIXME: Make calls to notifyFinished async
526     if (!isLoading() && !stillNeedsLoad())
527         client.notifyFinished(*this);
528 }
529
530 bool CachedResource::addClientToSet(CachedResourceClient& client)
531 {
532     if (m_preloadResult == PreloadResult::PreloadNotReferenced && client.shouldMarkAsReferenced()) {
533         if (isLoaded())
534             m_preloadResult = PreloadResult::PreloadReferencedWhileComplete;
535         else if (m_requestedFromNetworkingLayer)
536             m_preloadResult = PreloadResult::PreloadReferencedWhileLoading;
537         else
538             m_preloadResult = PreloadResult::PreloadReferenced;
539     }
540     if (allowsCaching() && !hasClients() && inCache())
541         MemoryCache::singleton().addToLiveResourcesSize(*this);
542
543     if ((m_type == Type::RawResource || m_type == Type::MainResource) && !m_response.isNull() && !m_proxyResource) {
544         // Certain resources (especially XHRs and main resources) do crazy things if an asynchronous load returns
545         // synchronously (e.g., scripts may not have set all the state they need to handle the load).
546         // Therefore, rather than immediately sending callbacks on a cache hit like other CachedResources,
547         // we schedule the callbacks and ensure we never finish synchronously.
548         ASSERT(!m_clientsAwaitingCallback.contains(&client));
549         m_clientsAwaitingCallback.add(&client, makeUnique<Callback>(*this, client));
550         return false;
551     }
552
553     m_clients.add(&client);
554     return true;
555 }
556
557 void CachedResource::removeClient(CachedResourceClient& client)
558 {
559     auto callback = m_clientsAwaitingCallback.take(&client);
560     if (callback) {
561         ASSERT(!m_clients.contains(&client));
562         callback->cancel();
563         callback = nullptr;
564     } else {
565         ASSERT(m_clients.contains(&client));
566         m_clients.remove(&client);
567         didRemoveClient(client);
568     }
569
570     if (deleteIfPossible()) {
571         // `this` object is dead here.
572         return;
573     }
574
575     if (hasClients())
576         return;
577
578     auto& memoryCache = MemoryCache::singleton();
579     if (allowsCaching() && inCache()) {
580         memoryCache.removeFromLiveResourcesSize(*this);
581         memoryCache.removeFromLiveDecodedResourcesList(*this);
582     }
583     if (!m_switchingClientsToRevalidatedResource)
584         allClientsRemoved();
585     destroyDecodedDataIfNeeded();
586
587     if (!allowsCaching())
588         return;
589
590     if (response().cacheControlContainsNoStore() && url().protocolIs("https")) {
591         // RFC2616 14.9.2:
592         // "no-store: ... MUST make a best-effort attempt to remove the information from volatile storage as promptly as possible"
593         // "... History buffers MAY store such responses as part of their normal operation."
594         // We allow non-secure content to be reused in history, but we do not allow secure content to be reused.
595         memoryCache.remove(*this);
596     }
597     memoryCache.pruneSoon();
598 }
599
600 void CachedResource::allClientsRemoved()
601 {
602     if (isLinkPreload() && m_loader)
603         m_loader->cancelIfNotFinishing();
604 }
605
606 void CachedResource::destroyDecodedDataIfNeeded()
607 {
608     if (!m_decodedSize)
609         return;
610     if (!MemoryCache::singleton().deadDecodedDataDeletionInterval())
611         return;
612     m_decodedDataDeletionTimer.restart();
613 }
614
615 void CachedResource::decodedDataDeletionTimerFired()
616 {
617     destroyDecodedData();
618 }
619
620 bool CachedResource::deleteIfPossible()
621 {
622     if (canDelete()) {
623         LOG(ResourceLoading, "CachedResource %p deleteIfPossible - can delete, in cache %d", this, inCache());
624         if (!inCache()) {
625             InspectorInstrumentation::willDestroyCachedResource(*this);
626             delete this;
627             return true;
628         }
629         if (m_data)
630             m_data->hintMemoryNotNeededSoon();
631     }
632
633     LOG(ResourceLoading, "CachedResource %p deleteIfPossible - can't delete (hasClients %d loader %p preloadCount %u handleCount %u resourceToRevalidate %p proxyResource %p)", this, hasClients(), m_loader.get(), m_preloadCount, m_handleCount, m_resourceToRevalidate, m_proxyResource);
634     return false;
635 }
636
637 void CachedResource::setDecodedSize(unsigned size)
638 {
639     if (size == m_decodedSize)
640         return;
641
642     long long delta = static_cast<long long>(size) - m_decodedSize;
643
644     // The object must be moved to a different queue, since its size has been changed.
645     // Remove before updating m_decodedSize, so we find the resource in the correct LRU list.
646     if (allowsCaching() && inCache())
647         MemoryCache::singleton().removeFromLRUList(*this);
648
649     m_decodedSize = size;
650    
651     if (allowsCaching() && inCache()) {
652         auto& memoryCache = MemoryCache::singleton();
653         // Now insert into the new LRU list.
654         memoryCache.insertInLRUList(*this);
655         
656         // Insert into or remove from the live decoded list if necessary.
657         // When inserting into the LiveDecodedResourcesList it is possible
658         // that the m_lastDecodedAccessTime is still zero or smaller than
659         // the m_lastDecodedAccessTime of the current list head. This is a
660         // violation of the invariant that the list is to be kept sorted
661         // by access time. The weakening of the invariant does not pose
662         // a problem. For more details please see: https://bugs.webkit.org/show_bug.cgi?id=30209
663         bool inLiveDecodedResourcesList = memoryCache.inLiveDecodedResourcesList(*this);
664         if (m_decodedSize && !inLiveDecodedResourcesList && hasClients())
665             memoryCache.insertInLiveDecodedResourcesList(*this);
666         else if (!m_decodedSize && inLiveDecodedResourcesList)
667             memoryCache.removeFromLiveDecodedResourcesList(*this);
668
669         // Update the cache's size totals.
670         memoryCache.adjustSize(hasClients(), delta);
671     }
672 }
673
674 void CachedResource::setEncodedSize(unsigned size)
675 {
676     if (size == m_encodedSize)
677         return;
678
679     long long delta = static_cast<long long>(size) - m_encodedSize;
680
681     // The object must be moved to a different queue, since its size has been changed.
682     // Remove before updating m_encodedSize, so we find the resource in the correct LRU list.
683     if (allowsCaching() && inCache())
684         MemoryCache::singleton().removeFromLRUList(*this);
685
686     m_encodedSize = size;
687
688     if (allowsCaching() && inCache()) {
689         auto& memoryCache = MemoryCache::singleton();
690         memoryCache.insertInLRUList(*this);
691         memoryCache.adjustSize(hasClients(), delta);
692     }
693 }
694
695 void CachedResource::didAccessDecodedData(MonotonicTime timeStamp)
696 {
697     m_lastDecodedAccessTime = timeStamp;
698     
699     if (allowsCaching() && inCache()) {
700         auto& memoryCache = MemoryCache::singleton();
701         if (memoryCache.inLiveDecodedResourcesList(*this)) {
702             memoryCache.removeFromLiveDecodedResourcesList(*this);
703             memoryCache.insertInLiveDecodedResourcesList(*this);
704         }
705         memoryCache.pruneSoon();
706     }
707 }
708     
709 void CachedResource::setResourceToRevalidate(CachedResource* resource) 
710
711     ASSERT(resource);
712     ASSERT(!m_resourceToRevalidate);
713     ASSERT(resource != this);
714     ASSERT(m_handlesToRevalidate.isEmpty());
715     ASSERT(resource->type() == type());
716     ASSERT(!resource->m_proxyResource);
717
718     LOG(ResourceLoading, "CachedResource %p setResourceToRevalidate %p", this, resource);
719
720     resource->m_proxyResource = this;
721     m_resourceToRevalidate = resource;
722 }
723
724 void CachedResource::clearResourceToRevalidate() 
725 {
726     ASSERT(m_resourceToRevalidate);
727     ASSERT(m_resourceToRevalidate->m_proxyResource == this);
728
729     if (m_switchingClientsToRevalidatedResource)
730         return;
731
732     m_resourceToRevalidate->m_proxyResource = nullptr;
733     m_resourceToRevalidate->deleteIfPossible();
734
735     m_handlesToRevalidate.clear();
736     m_resourceToRevalidate = nullptr;
737     deleteIfPossible();
738 }
739     
740 void CachedResource::switchClientsToRevalidatedResource()
741 {
742     ASSERT(m_resourceToRevalidate);
743     ASSERT(m_resourceToRevalidate->inCache());
744     ASSERT(!inCache());
745
746     LOG(ResourceLoading, "CachedResource %p switchClientsToRevalidatedResource %p", this, m_resourceToRevalidate);
747
748     m_switchingClientsToRevalidatedResource = true;
749     for (auto& handle : m_handlesToRevalidate) {
750         handle->m_resource = m_resourceToRevalidate;
751         m_resourceToRevalidate->registerHandle(handle);
752         --m_handleCount;
753     }
754     ASSERT(!m_handleCount);
755     m_handlesToRevalidate.clear();
756
757     Vector<CachedResourceClient*> clientsToMove;
758     for (auto& entry : m_clients) {
759         CachedResourceClient* client = entry.key;
760         unsigned count = entry.value;
761         while (count) {
762             clientsToMove.append(client);
763             --count;
764         }
765     }
766
767     for (auto& client : clientsToMove)
768         removeClient(*client);
769     ASSERT(m_clients.isEmpty());
770
771     for (auto& client : clientsToMove)
772         m_resourceToRevalidate->addClientToSet(*client);
773     for (auto& client : clientsToMove) {
774         // Calling didAddClient may do anything, including trying to cancel revalidation.
775         // Assert that it didn't succeed.
776         ASSERT(m_resourceToRevalidate);
777         // Calling didAddClient for a client may end up removing another client. In that case it won't be in the set anymore.
778         if (m_resourceToRevalidate->m_clients.contains(client))
779             m_resourceToRevalidate->didAddClient(*client);
780     }
781     m_switchingClientsToRevalidatedResource = false;
782 }
783
784 void CachedResource::updateResponseAfterRevalidation(const ResourceResponse& validatingResponse)
785 {
786     m_responseTimestamp = WallTime::now();
787
788     updateResponseHeadersAfterRevalidation(m_response, validatingResponse);
789 }
790
791 void CachedResource::registerHandle(CachedResourceHandleBase* h)
792 {
793     ++m_handleCount;
794     if (m_resourceToRevalidate)
795         m_handlesToRevalidate.add(h);
796 }
797
798 void CachedResource::unregisterHandle(CachedResourceHandleBase* h)
799 {
800     ASSERT(m_handleCount > 0);
801     --m_handleCount;
802
803     if (m_resourceToRevalidate)
804          m_handlesToRevalidate.remove(h);
805
806     if (!m_handleCount)
807         deleteIfPossible();
808 }
809
810 bool CachedResource::canUseCacheValidator() const
811 {
812     if (m_loading || errorOccurred())
813         return false;
814
815     if (m_response.cacheControlContainsNoStore())
816         return false;
817     return m_response.hasCacheValidatorFields();
818 }
819
820 CachedResource::RevalidationDecision CachedResource::makeRevalidationDecision(CachePolicy cachePolicy) const
821 {    
822     switch (cachePolicy) {
823     case CachePolicyHistoryBuffer:
824         return RevalidationDecision::No;
825
826     case CachePolicyReload:
827         return RevalidationDecision::YesDueToCachePolicy;
828
829     case CachePolicyRevalidate:
830         if (m_response.cacheControlContainsImmutable() && m_response.url().protocolIs("https")) {
831             if (isExpired())
832                 return RevalidationDecision::YesDueToExpired;
833             return RevalidationDecision::No;
834         }
835         return RevalidationDecision::YesDueToCachePolicy;
836
837     case CachePolicyVerify:
838         if (m_response.cacheControlContainsNoCache())
839             return RevalidationDecision::YesDueToNoCache;
840         // FIXME: Cache-Control:no-store should prevent storing, not reuse.
841         if (m_response.cacheControlContainsNoStore())
842             return RevalidationDecision::YesDueToNoStore;
843
844         if (isExpired())
845             return RevalidationDecision::YesDueToExpired;
846
847         return RevalidationDecision::No;
848     };
849     ASSERT_NOT_REACHED();
850     return RevalidationDecision::No;
851 }
852
853 bool CachedResource::redirectChainAllowsReuse(ReuseExpiredRedirectionOrNot reuseExpiredRedirection) const
854 {
855     return WebCore::redirectChainAllowsReuse(m_redirectChainCacheStatus, reuseExpiredRedirection);
856 }
857
858 bool CachedResource::varyHeaderValuesMatch(const ResourceRequest& request)
859 {
860     if (m_varyingHeaderValues.isEmpty())
861         return true;
862
863     return verifyVaryingRequestHeaders(cookieJar(), m_varyingHeaderValues, request, sessionID());
864 }
865
866 unsigned CachedResource::overheadSize() const
867 {
868     static const int kAverageClientsHashMapSize = 384;
869     return sizeof(CachedResource) + m_response.memoryUsage() + kAverageClientsHashMapSize + m_resourceRequest.url().string().length() * 2;
870 }
871
872 bool CachedResource::areAllClientsXMLHttpRequests() const
873 {
874     if (type() != Type::RawResource)
875         return false;
876
877     for (auto& client : m_clients) {
878         if (!client.key->isXMLHttpRequest())
879             return false;
880     }
881     return true;
882 }
883
884 void CachedResource::setLoadPriority(const Optional<ResourceLoadPriority>& loadPriority)
885 {
886     if (loadPriority)
887         m_loadPriority = loadPriority.value();
888     else
889         m_loadPriority = defaultPriorityForResourceType(type());
890 }
891
892 inline CachedResource::Callback::Callback(CachedResource& resource, CachedResourceClient& client)
893     : m_resource(resource)
894     , m_client(client)
895     , m_timer(*this, &Callback::timerFired)
896 {
897     m_timer.startOneShot(0_s);
898 }
899
900 inline void CachedResource::Callback::cancel()
901 {
902     if (m_timer.isActive())
903         m_timer.stop();
904 }
905
906 void CachedResource::Callback::timerFired()
907 {
908     m_resource.didAddClient(m_client);
909 }
910
911 #if USE(FOUNDATION) || USE(SOUP)
912
913 void CachedResource::tryReplaceEncodedData(SharedBuffer& newBuffer)
914 {
915     if (!m_data)
916         return;
917     
918     if (!mayTryReplaceEncodedData())
919         return;
920
921     // We have to do the memcmp because we can't tell if the replacement file backed data is for the
922     // same resource or if we made a second request with the same URL which gave us a different
923     // resource. We have seen this happen for cached POST resources.
924     if (m_data->size() != newBuffer.size() || memcmp(m_data->data(), newBuffer.data(), m_data->size()))
925         return;
926
927     m_data->clear();
928     m_data->append(newBuffer);
929     didReplaceSharedBufferContents();
930 }
931
932 #endif
933
934 }