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