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/*
* Copyright (C) 2007, 2014, 2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "BackForwardCache.h"
#include "ApplicationCacheHost.h"
#include "BackForwardController.h"
#include "CachedPage.h"
#include "DOMWindow.h"
#include "DeviceMotionController.h"
#include "DeviceOrientationController.h"
#include "DiagnosticLoggingClient.h"
#include "DiagnosticLoggingKeys.h"
#include "Document.h"
#include "DocumentLoader.h"
#include "FocusController.h"
#include "Frame.h"
#include "FrameLoader.h"
#include "FrameLoaderClient.h"
#include "FrameView.h"
#include "HistoryController.h"
#include "IgnoreOpensDuringUnloadCountIncrementer.h"
#include "Logging.h"
#include "Page.h"
#include "Quirks.h"
#include "ScriptDisallowedScope.h"
#include "Settings.h"
#include "SubframeLoader.h"
#include <pal/Logging.h>
#include <wtf/MemoryPressureHandler.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/SetForScope.h>
#include <wtf/text/CString.h>
#include <wtf/text/StringConcatenate.h>
namespace WebCore {
#define PCLOG(...) LOG(BackForwardCache, "%*s%s", indentLevel*4, "", makeString(__VA_ARGS__).utf8().data())
static inline void logBackForwardCacheFailureDiagnosticMessage(DiagnosticLoggingClient& client, const String& reason)
{
client.logDiagnosticMessage(DiagnosticLoggingKeys::backForwardCacheFailureKey(), reason, ShouldSample::No);
}
static inline void logBackForwardCacheFailureDiagnosticMessage(Page* page, const String& reason)
{
if (!page)
return;
logBackForwardCacheFailureDiagnosticMessage(page->diagnosticLoggingClient(), reason);
}
static bool canCacheFrame(Frame& frame, DiagnosticLoggingClient& diagnosticLoggingClient, unsigned indentLevel)
{
PCLOG("+---");
FrameLoader& frameLoader = frame.loader();
// Prevent page caching if a subframe is still in provisional load stage.
// We only do this check for subframes because the main frame is reused when navigating to a new page.
if (!frame.isMainFrame() && frameLoader.state() == FrameState::Provisional) {
PCLOG(" -Frame is in provisional load stage");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::provisionalLoadKey());
return false;
}
if (frame.isMainFrame() && frameLoader.stateMachine().isDisplayingInitialEmptyDocument()) {
PCLOG(" -MainFrame is displaying initial empty document");
return false;
}
if (!frame.document()) {
PCLOG(" -Frame has no document");
return false;
}
if (frame.document()->shouldPreventEnteringBackForwardCacheForTesting()) {
PCLOG(" -Back/Forward caching is disabled for testing");
return false;
}
if (!frame.document()->frame()) {
PCLOG(" -Document is detached from frame");
ASSERT_NOT_REACHED();
return false;
}
DocumentLoader* documentLoader = frameLoader.documentLoader();
if (!documentLoader) {
PCLOG(" -There is no DocumentLoader object");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::noDocumentLoaderKey());
return false;
}
URL currentURL = documentLoader->url();
URL newURL = frameLoader.provisionalDocumentLoader() ? frameLoader.provisionalDocumentLoader()->url() : URL();
if (!newURL.isEmpty())
PCLOG(" Determining if frame can be cached navigating from (", currentURL.string(), ") to (", newURL.string(), "):");
else
PCLOG(" Determining if subframe with URL (", currentURL.string(), ") can be cached:");
bool isCacheable = true;
if (frame.isMainFrame() && frame.document()->quirks().shouldBypassBackForwardCache()) {
PCLOG(" -Disabled by site-specific quirk");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::siteSpecificQuirkKey());
isCacheable = false;
}
// Do not cache error pages (these can be recognized as pages with substitute data or unreachable URLs).
if (documentLoader->substituteData().isValid() && !documentLoader->substituteData().failingURL().isEmpty()) {
PCLOG(" -Frame is an error page");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::isErrorPageKey());
isCacheable = false;
}
if (frameLoader.subframeLoader().containsPlugins() && !frame.page()->settings().backForwardCacheSupportsPlugins()) {
PCLOG(" -Frame contains plugins");
isCacheable = false;
}
if (frame.isMainFrame() && frame.document() && frame.document()->url().protocolIs("https") && documentLoader->response().cacheControlContainsNoStore()) {
PCLOG(" -Frame is HTTPS, and cache control prohibits storing");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::httpsNoStoreKey());
isCacheable = false;
}
if (frame.isMainFrame() && !frameLoader.history().currentItem()) {
PCLOG(" -Main frame has no current history item");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::noCurrentHistoryItemKey());
isCacheable = false;
}
if (frame.isMainFrame() && frame.view() && !frame.view()->isVisuallyNonEmpty()) {
PCLOG(" -Main frame is visually empty");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::visuallyEmptyKey());
isCacheable = false;
}
if (frameLoader.quickRedirectComing()) {
PCLOG(" -Quick redirect is coming");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::quirkRedirectComingKey());
isCacheable = false;
}
if (documentLoader->isLoading()) {
PCLOG(" -DocumentLoader is still loading");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::isLoadingKey());
isCacheable = false;
}
if (documentLoader->isStopping()) {
PCLOG(" -DocumentLoader is in the middle of stopping");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::documentLoaderStoppingKey());
isCacheable = false;
}
// FIXME: We should investigating caching frames that have an associated
// application cache. <rdar://problem/5917899> tracks that work.
if (!documentLoader->applicationCacheHost().canCacheInBackForwardCache()) {
PCLOG(" -The DocumentLoader uses an application cache");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::applicationCacheKey());
isCacheable = false;
}
if (!frameLoader.client().canCachePage()) {
PCLOG(" -The client says this frame cannot be cached");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::deniedByClientKey());
isCacheable = false;
}
for (Frame* child = frame.tree().firstChild(); child; child = child->tree().nextSibling()) {
if (!canCacheFrame(*child, diagnosticLoggingClient, indentLevel + 1))
isCacheable = false;
}
PCLOG(isCacheable ? " Frame CAN be cached" : " Frame CANNOT be cached");
PCLOG("+---");
return isCacheable;
}
static bool canCachePage(Page& page)
{
RELEASE_ASSERT(!page.isRestoringCachedPage());
unsigned indentLevel = 0;
PCLOG("--------\n Determining if page can be cached:");
DiagnosticLoggingClient& diagnosticLoggingClient = page.diagnosticLoggingClient();
bool isCacheable = canCacheFrame(page.mainFrame(), diagnosticLoggingClient, indentLevel + 1);
if (!page.settings().usesBackForwardCache() || page.isResourceCachingDisabledByWebInspector()) {
PCLOG(" -Page settings says b/f cache disabled");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::isDisabledKey());
isCacheable = false;
}
#if ENABLE(DEVICE_ORIENTATION) && !PLATFORM(IOS_FAMILY)
if (DeviceMotionController::isActiveAt(&page)) {
PCLOG(" -Page is using DeviceMotion");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::deviceMotionKey());
isCacheable = false;
}
if (DeviceOrientationController::isActiveAt(&page)) {
PCLOG(" -Page is using DeviceOrientation");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::deviceOrientationKey());
isCacheable = false;
}
#endif
FrameLoadType loadType = page.mainFrame().loader().loadType();
switch (loadType) {
case FrameLoadType::Reload:
// No point writing to the cache on a reload, since we will just write over it again when we leave that page.
PCLOG(" -Load type is: Reload");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::reloadKey());
isCacheable = false;
break;
case FrameLoadType::Same: // user loads same URL again (but not reload button)
// No point writing to the cache on a same load, since we will just write over it again when we leave that page.
PCLOG(" -Load type is: Same");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::sameLoadKey());
isCacheable = false;
break;
case FrameLoadType::RedirectWithLockedBackForwardList:
// Don't write to the cache if in the middle of a redirect, since we will want to store the final page we end up on.
PCLOG(" -Load type is: RedirectWithLockedBackForwardList");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::redirectKey());
isCacheable = false;
break;
case FrameLoadType::Replace:
// No point writing to the cache on a replace, since we will just write over it again when we leave that page.
PCLOG(" -Load type is: Replace");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::replaceKey());
isCacheable = false;
break;
case FrameLoadType::ReloadFromOrigin: {
// No point writing to the cache on a reload, since we will just write over it again when we leave that page.
PCLOG(" -Load type is: ReloadFromOrigin");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::reloadFromOriginKey());
isCacheable = false;
break;
}
case FrameLoadType::ReloadExpiredOnly: {
// No point writing to the cache on a reload, since we will just write over it again when we leave that page.
PCLOG(" -Load type is: ReloadRevalidatingExpired");
logBackForwardCacheFailureDiagnosticMessage(diagnosticLoggingClient, DiagnosticLoggingKeys::reloadRevalidatingExpiredKey());
isCacheable = false;
break;
}
case FrameLoadType::Standard:
case FrameLoadType::Back:
case FrameLoadType::Forward:
case FrameLoadType::IndexedBackForward: // a multi-item hop in the backforward list
// Cacheable.
break;
}
if (isCacheable)
PCLOG(" Page CAN be cached\n--------");
else
PCLOG(" Page CANNOT be cached\n--------");
diagnosticLoggingClient.logDiagnosticMessageWithResult(DiagnosticLoggingKeys::backForwardCacheKey(), DiagnosticLoggingKeys::canCacheKey(), isCacheable ? DiagnosticLoggingResultPass : DiagnosticLoggingResultFail, ShouldSample::No);
return isCacheable;
}
BackForwardCache& BackForwardCache::singleton()
{
static NeverDestroyed<BackForwardCache> globalBackForwardCache;
return globalBackForwardCache;
}
BackForwardCache::BackForwardCache()
{
static std::once_flag onceFlag;
std::call_once(onceFlag, [] {
PAL::registerNotifyCallback("com.apple.WebKit.showBackForwardCache", [] {
BackForwardCache::singleton().dump();
});
});
}
void BackForwardCache::dump() const
{
WTFLogAlways("Back/Forward Cache:");
for (auto& item : m_items) {
CachedPage& cachedPage = *item->m_cachedPage;
WTFLogAlways(" Page %p, document %p %s", &cachedPage.page(), cachedPage.document(), cachedPage.document() ? cachedPage.document()->url().string().utf8().data() : "");
}
}
bool BackForwardCache::canCache(Page& page) const
{
if (!m_maxSize) {
logBackForwardCacheFailureDiagnosticMessage(&page, DiagnosticLoggingKeys::isDisabledKey());
return false;
}
if (MemoryPressureHandler::singleton().isUnderMemoryPressure()) {
logBackForwardCacheFailureDiagnosticMessage(&page, DiagnosticLoggingKeys::underMemoryPressureKey());
return false;
}
return canCachePage(page);
}
void BackForwardCache::pruneToSizeNow(unsigned size, PruningReason pruningReason)
{
SetForScope<unsigned> change(m_maxSize, size);
prune(pruningReason);
}
void BackForwardCache::setMaxSize(unsigned maxSize)
{
m_maxSize = maxSize;
prune(PruningReason::None);
}
unsigned BackForwardCache::frameCount() const
{
unsigned frameCount = m_items.size();
for (auto& item : m_items) {
ASSERT(item->m_cachedPage);
frameCount += item->m_cachedPage->cachedMainFrame()->descendantFrameCount();
}
return frameCount;
}
void BackForwardCache::markPagesForDeviceOrPageScaleChanged(Page& page)
{
for (auto& item : m_items) {
CachedPage& cachedPage = *item->m_cachedPage;
if (&page.mainFrame() == &cachedPage.cachedMainFrame()->view()->frame())
cachedPage.markForDeviceOrPageScaleChanged();
}
}
void BackForwardCache::markPagesForContentsSizeChanged(Page& page)
{
for (auto& item : m_items) {
CachedPage& cachedPage = *item->m_cachedPage;
if (&page.mainFrame() == &cachedPage.cachedMainFrame()->view()->frame())
cachedPage.markForContentsSizeChanged();
}
}
#if ENABLE(VIDEO)
void BackForwardCache::markPagesForCaptionPreferencesChanged()
{
for (auto& item : m_items) {
ASSERT(item->m_cachedPage);
item->m_cachedPage->markForCaptionPreferencesChanged();
}
}
#endif
static String pruningReasonToDiagnosticLoggingKey(PruningReason pruningReason)
{
switch (pruningReason) {
case PruningReason::MemoryPressure:
return DiagnosticLoggingKeys::prunedDueToMemoryPressureKey();
case PruningReason::ProcessSuspended:
return DiagnosticLoggingKeys::prunedDueToProcessSuspended();
case PruningReason::ReachedMaxSize:
return DiagnosticLoggingKeys::prunedDueToMaxSizeReached();
case PruningReason::None:
break;
}
ASSERT_NOT_REACHED();
return emptyString();
}
static void setBackForwardCacheState(Page& page, Document::BackForwardCacheState BackForwardCacheState)
{
for (Frame* frame = &page.mainFrame(); frame; frame = frame->tree().traverseNext()) {
if (auto* document = frame->document())
document->setBackForwardCacheState(BackForwardCacheState);
}
}
// When entering back/forward cache, tear down the render tree before setting the in-cache flag.
// This maintains the invariant that render trees are never present in the back/forward cache.
// Note that destruction happens bottom-up so that the main frame's tree dies last.
static void destroyRenderTree(Frame& mainFrame)
{
for (Frame* frame = mainFrame.tree().traversePrevious(CanWrap::Yes); frame; frame = frame->tree().traversePrevious(CanWrap::No)) {
if (!frame->document())
continue;
auto& document = *frame->document();
if (document.hasLivingRenderTree())
document.destroyRenderTree();
}
}
static void firePageHideEventRecursively(Frame& frame)
{
auto* document = frame.document();
if (!document)
return;
// stopLoading() will fire the pagehide event in each subframe and the HTML specification states
// that the parent document's ignore-opens-during-unload counter should be incremented while the
// pagehide event is being fired in its subframes:
// https://html.spec.whatwg.org/multipage/browsers.html#unload-a-document
IgnoreOpensDuringUnloadCountIncrementer ignoreOpensDuringUnloadCountIncrementer(document);
frame.loader().stopLoading(UnloadEventPolicy::UnloadAndPageHide);
for (RefPtr<Frame> child = frame.tree().firstChild(); child; child = child->tree().nextSibling())
firePageHideEventRecursively(*child);
}
std::unique_ptr<CachedPage> BackForwardCache::trySuspendPage(Page& page, ForceSuspension forceSuspension)
{
page.mainFrame().loader().stopForBackForwardCache();
if (forceSuspension == ForceSuspension::No && !canCache(page))
return nullptr;
ASSERT_WITH_MESSAGE(!page.isUtilityPage(), "Utility pages such as SVGImage pages should never go into BackForwardCache");
setBackForwardCacheState(page, Document::AboutToEnterBackForwardCache);
// Focus the main frame, defocusing a focused subframe (if we have one). We do this here,
// before the page enters the back/forward cache, while we still can dispatch DOM blur/focus events.
if (CheckedRef focusController { page.focusController() }; focusController->focusedFrame())
focusController->setFocusedFrame(&page.mainFrame());
// Fire the pagehide event in all frames.
firePageHideEventRecursively(page.mainFrame());
destroyRenderTree(page.mainFrame());
// Stop all loads again before checking if we can still cache the page after firing the pagehide
// event, since the page may have started ping loads in its pagehide event handler.
page.mainFrame().loader().stopForBackForwardCache();
// Check that the page is still page-cacheable after firing the pagehide event. The JS event handlers
// could have altered the page in a way that could prevent caching.
if (forceSuspension == ForceSuspension::No && !canCache(page)) {
setBackForwardCacheState(page, Document::NotInBackForwardCache);
return nullptr;
}
setBackForwardCacheState(page, Document::InBackForwardCache);
// Make sure we don't fire any JS events in this scope.
ScriptDisallowedScope::InMainThread scriptDisallowedScope;
return makeUnique<CachedPage>(page);
}
bool BackForwardCache::addIfCacheable(HistoryItem& item, Page* page)
{
if (item.isInBackForwardCache())
return false;
if (!page)
return false;
auto cachedPage = trySuspendPage(*page, ForceSuspension::No);
if (!cachedPage)
return false;
{
// Make sure we don't fire any JS events in this scope.
ScriptDisallowedScope::InMainThread scriptDisallowedScope;
item.setCachedPage(WTFMove(cachedPage));
item.m_pruningReason = PruningReason::None;
m_items.add(&item);
}
prune(PruningReason::ReachedMaxSize);
RELEASE_LOG(BackForwardCache, "BackForwardCache::addIfCacheable item: %s, size: %u / %u", item.identifier().string().utf8().data(), pageCount(), maxSize());
return true;
}
std::unique_ptr<CachedPage> BackForwardCache::suspendPage(Page& page)
{
RELEASE_LOG(BackForwardCache, "BackForwardCache::suspendPage()");
return trySuspendPage(page, ForceSuspension::Yes);
}
std::unique_ptr<CachedPage> BackForwardCache::take(HistoryItem& item, Page* page)
{
if (!item.m_cachedPage) {
if (item.m_pruningReason != PruningReason::None)
logBackForwardCacheFailureDiagnosticMessage(page, pruningReasonToDiagnosticLoggingKey(item.m_pruningReason));
return nullptr;
}
m_items.remove(&item);
std::unique_ptr<CachedPage> cachedPage = item.takeCachedPage();
RELEASE_LOG(BackForwardCache, "BackForwardCache::take item: %s, size: %u / %u", item.identifier().string().utf8().data(), pageCount(), maxSize());
if (cachedPage->hasExpired() || (page && page->isResourceCachingDisabledByWebInspector())) {
LOG(BackForwardCache, "Not restoring page for %s from back/forward cache because cache entry has expired", item.url().string().ascii().data());
logBackForwardCacheFailureDiagnosticMessage(page, DiagnosticLoggingKeys::expiredKey());
return nullptr;
}
return cachedPage;
}
void BackForwardCache::removeAllItemsForPage(Page& page)
{
#if ASSERT_ENABLED
ASSERT_WITH_MESSAGE(!m_isInRemoveAllItemsForPage, "We should not reenter this method");
SetForScope<bool> inRemoveAllItemsForPageScope { m_isInRemoveAllItemsForPage, true };
#endif
for (auto it = m_items.begin(); it != m_items.end();) {
// Increment iterator first so it stays valid after the removal.
auto current = it;
++it;
if (&(*current)->m_cachedPage->page() == &page) {
RELEASE_LOG(BackForwardCache, "BackForwardCache::removeAllItemsForPage removing item: %s, size: %u / %u", (*current)->identifier().string().utf8().data(), pageCount() - 1, maxSize());
(*current)->setCachedPage(nullptr);
m_items.remove(current);
}
}
}
CachedPage* BackForwardCache::get(HistoryItem& item, Page* page)
{
CachedPage* cachedPage = item.m_cachedPage.get();
if (!cachedPage) {
if (item.m_pruningReason != PruningReason::None)
logBackForwardCacheFailureDiagnosticMessage(page, pruningReasonToDiagnosticLoggingKey(item.m_pruningReason));
return nullptr;
}
if (cachedPage->hasExpired() || (page && page->isResourceCachingDisabledByWebInspector())) {
LOG(BackForwardCache, "Not restoring page for %s from back/forward cache because cache entry has expired", item.url().string().ascii().data());
logBackForwardCacheFailureDiagnosticMessage(page, DiagnosticLoggingKeys::expiredKey());
remove(item);
return nullptr;
}
return cachedPage;
}
void BackForwardCache::remove(HistoryItem& item)
{
// Safely ignore attempts to remove items not in the cache.
if (!item.m_cachedPage)
return;
m_items.remove(&item);
item.setCachedPage(nullptr);
RELEASE_LOG(BackForwardCache, "BackForwardCache::remove item: %s, size: %u / %u", item.identifier().string().utf8().data(), pageCount(), maxSize());
}
void BackForwardCache::prune(PruningReason pruningReason)
{
while (pageCount() > maxSize()) {
auto oldestItem = m_items.takeFirst();
oldestItem->setCachedPage(nullptr);
oldestItem->m_pruningReason = pruningReason;
RELEASE_LOG(BackForwardCache, "BackForwardCache::prune removing item: %s, size: %u / %u", oldestItem->identifier().string().utf8().data(), pageCount(), maxSize());
}
}
} // namespace WebCore