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/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* (C) 1999 Antti Koivisto (koivisto@kde.org)
* Copyright (C) 2004-2017 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "ImageLoader.h"
#include "BitmapImage.h"
#include "CachedImage.h"
#include "CachedResourceLoader.h"
#include "CachedResourceRequest.h"
#include "CrossOriginAccessControl.h"
#include "Document.h"
#include "Element.h"
#include "Event.h"
#include "EventNames.h"
#include "EventSender.h"
#include "Frame.h"
#include "FrameLoader.h"
#include "HTMLNames.h"
#include "HTMLObjectElement.h"
#include "HTMLParserIdioms.h"
#include "InspectorInstrumentation.h"
#include "JSDOMPromiseDeferred.h"
#include "LazyLoadImageObserver.h"
#include "Page.h"
#include "RenderImage.h"
#include "RenderSVGImage.h"
#include "RuntimeEnabledFeatures.h"
#include <wtf/NeverDestroyed.h>
#if ENABLE(VIDEO)
#include "RenderVideo.h"
#endif
#if ASSERT_ENABLED
// ImageLoader objects are allocated as members of other objects, so generic pointer check would always fail.
namespace WTF {
template<> struct ValueCheck<WebCore::ImageLoader*> {
typedef WebCore::ImageLoader* TraitType;
static void checkConsistency(const WebCore::ImageLoader* p)
{
if (!p)
return;
ValueCheck<WebCore::Element*>::checkConsistency(&p->element());
}
};
} // namespace WTF
#endif // ASSERT_ENABLED
namespace WebCore {
static ImageEventSender& beforeLoadEventSender()
{
static NeverDestroyed<ImageEventSender> sender(eventNames().beforeloadEvent);
return sender;
}
static ImageEventSender& loadEventSender()
{
static NeverDestroyed<ImageEventSender> sender(eventNames().loadEvent);
return sender;
}
static ImageEventSender& errorEventSender()
{
static NeverDestroyed<ImageEventSender> sender(eventNames().errorEvent);
return sender;
}
static inline bool pageIsBeingDismissed(Document& document)
{
Frame* frame = document.frame();
return frame && frame->loader().pageDismissalEventBeingDispatched() != FrameLoader::PageDismissalType::None;
}
ImageLoader::ImageLoader(Element& element)
: m_element(element)
, m_image(nullptr)
, m_derefElementTimer(*this, &ImageLoader::timerFired)
, m_hasPendingBeforeLoadEvent(false)
, m_hasPendingLoadEvent(false)
, m_hasPendingErrorEvent(false)
, m_imageComplete(true)
, m_loadManually(false)
, m_elementIsProtected(false)
{
}
ImageLoader::~ImageLoader()
{
if (m_image)
m_image->removeClient(*this);
ASSERT(m_hasPendingBeforeLoadEvent || !beforeLoadEventSender().hasPendingEvents(*this));
if (m_hasPendingBeforeLoadEvent)
beforeLoadEventSender().cancelEvent(*this);
ASSERT(m_hasPendingLoadEvent || !loadEventSender().hasPendingEvents(*this));
if (m_hasPendingLoadEvent)
loadEventSender().cancelEvent(*this);
ASSERT(m_hasPendingErrorEvent || !errorEventSender().hasPendingEvents(*this));
if (m_hasPendingErrorEvent)
errorEventSender().cancelEvent(*this);
}
void ImageLoader::clearImage()
{
clearImageWithoutConsideringPendingLoadEvent();
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
}
void ImageLoader::clearImageWithoutConsideringPendingLoadEvent()
{
ASSERT(m_failedLoadURL.isEmpty());
CachedImage* oldImage = m_image.get();
if (oldImage) {
m_image = nullptr;
if (m_hasPendingBeforeLoadEvent) {
beforeLoadEventSender().cancelEvent(*this);
m_hasPendingBeforeLoadEvent = false;
}
if (m_hasPendingLoadEvent) {
loadEventSender().cancelEvent(*this);
m_hasPendingLoadEvent = false;
}
if (m_hasPendingErrorEvent) {
errorEventSender().cancelEvent(*this);
m_hasPendingErrorEvent = false;
}
m_imageComplete = true;
if (oldImage)
oldImage->removeClient(*this);
}
if (RenderImageResource* imageResource = renderImageResource())
imageResource->resetAnimation();
}
void ImageLoader::updateFromElement(RelevantMutation relevantMutation)
{
// If we're not making renderers for the page, then don't load images. We don't want to slow
// down the raw HTML parsing case by loading images we don't intend to display.
Document& document = element().document();
if (!document.hasLivingRenderTree())
return;
AtomString attr = element().imageSourceURL();
// Avoid loading a URL we already failed to load.
if (!m_failedLoadURL.isEmpty() && attr == m_failedLoadURL)
return;
// Do not load any image if the 'src' attribute is missing or if it is
// an empty string.
CachedResourceHandle<CachedImage> newImage = nullptr;
if (!attr.isNull() && !stripLeadingAndTrailingHTMLSpaces(attr).isEmpty()) {
ResourceLoaderOptions options = CachedResourceLoader::defaultCachedResourceOptions();
options.contentSecurityPolicyImposition = element().isInUserAgentShadowTree() ? ContentSecurityPolicyImposition::SkipPolicyCheck : ContentSecurityPolicyImposition::DoPolicyCheck;
options.sameOriginDataURLFlag = SameOriginDataURLFlag::Set;
bool isImageElement = is<HTMLImageElement>(element());
if (isImageElement)
options.referrerPolicy = downcast<HTMLImageElement>(element()).referrerPolicy();
auto crossOriginAttribute = element().attributeWithoutSynchronization(HTMLNames::crossoriginAttr);
// Use url from original request for lazy loads that are no longer in deferred state.
URL imageURL = m_lazyImageLoadState == LazyImageLoadState::LoadImmediately
? m_image->url() : document.completeURL(sourceURI(attr));
ResourceRequest resourceRequest(imageURL);
resourceRequest.setInspectorInitiatorNodeIdentifier(InspectorInstrumentation::identifierForNode(m_element));
auto request = createPotentialAccessControlRequest(WTFMove(resourceRequest), WTFMove(options), document, crossOriginAttribute);
request.setInitiator(element());
if (m_loadManually) {
bool autoLoadOtherImages = document.cachedResourceLoader().autoLoadImages();
document.cachedResourceLoader().setAutoLoadImages(false);
auto* page = m_element.document().page();
newImage = new CachedImage(WTFMove(request), page->sessionID(), &page->cookieJar());
newImage->setStatus(CachedResource::Pending);
newImage->setLoading(true);
document.cachedResourceLoader().m_documentResources.set(newImage->url().string(), newImage.get());
document.cachedResourceLoader().setAutoLoadImages(autoLoadOtherImages);
} else {
if (m_lazyImageLoadState == LazyImageLoadState::None && isImageElement) {
auto& imageElement = downcast<HTMLImageElement>(element());
if (imageElement.isLazyLoadable() && RuntimeEnabledFeatures::sharedFeatures().lazyImageLoadingEnabled()) {
m_lazyImageLoadState = LazyImageLoadState::Deferred;
request.setIgnoreForRequestCount(true);
}
}
auto imageLoading = (m_lazyImageLoadState == LazyImageLoadState::Deferred) ? ImageLoading::DeferredUntilVisible : ImageLoading::Immediate;
newImage = document.cachedResourceLoader().requestImage(WTFMove(request), imageLoading).value_or(nullptr);
}
// If we do not have an image here, it means that a cross-site
// violation occurred, or that the image was blocked via Content
// Security Policy, or the page is being dismissed. Trigger an
// error event if the page is not being dismissed.
if (!newImage && !pageIsBeingDismissed(document)) {
m_failedLoadURL = attr;
m_hasPendingErrorEvent = true;
errorEventSender().dispatchEventSoon(*this);
} else
clearFailedLoadURL();
} else if (!attr.isNull()) {
// Fire an error event if the url is empty.
m_failedLoadURL = attr;
m_hasPendingErrorEvent = true;
errorEventSender().dispatchEventSoon(*this);
}
CachedImage* oldImage = m_image.get();
if (newImage != oldImage || relevantMutation == RelevantMutation::Yes) {
if (m_hasPendingBeforeLoadEvent) {
beforeLoadEventSender().cancelEvent(*this);
m_hasPendingBeforeLoadEvent = false;
}
if (m_hasPendingLoadEvent) {
loadEventSender().cancelEvent(*this);
m_hasPendingLoadEvent = false;
}
// Cancel error events that belong to the previous load, which is now cancelled by changing the src attribute.
// If newImage is null and m_hasPendingErrorEvent is true, we know the error event has been just posted by
// this load and we should not cancel the event.
// FIXME: If both previous load and this one got blocked with an error, we can receive one error event instead of two.
if (m_hasPendingErrorEvent && newImage) {
errorEventSender().cancelEvent(*this);
m_hasPendingErrorEvent = false;
}
m_image = newImage;
m_hasPendingBeforeLoadEvent = !document.isImageDocument() && newImage;
m_hasPendingLoadEvent = newImage;
m_imageComplete = !newImage;
if (newImage) {
if (!document.isImageDocument()) {
if (!document.hasListenerType(Document::BEFORELOAD_LISTENER))
dispatchPendingBeforeLoadEvent();
else
beforeLoadEventSender().dispatchEventSoon(*this);
} else
updateRenderer();
if (m_lazyImageLoadState == LazyImageLoadState::Deferred)
LazyLoadImageObserver::observe(element());
// If newImage is cached, addClient() will result in the load event
// being queued to fire. Ensure this happens after beforeload is
// dispatched.
newImage->addClient(*this);
}
if (oldImage) {
oldImage->removeClient(*this);
updateRenderer();
}
}
if (RenderImageResource* imageResource = renderImageResource())
imageResource->resetAnimation();
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
}
void ImageLoader::updateFromElementIgnoringPreviousError(RelevantMutation relevantMutation)
{
clearFailedLoadURL();
updateFromElement(relevantMutation);
}
static inline void resolvePromises(Vector<RefPtr<DeferredPromise>>& promises)
{
ASSERT(!promises.isEmpty());
auto promisesToBeResolved = std::exchange(promises, { });
for (auto& promise : promisesToBeResolved)
promise->resolve();
}
static inline void rejectPromises(Vector<RefPtr<DeferredPromise>>& promises, const char* message)
{
ASSERT(!promises.isEmpty());
auto promisesToBeRejected = std::exchange(promises, { });
for (auto& promise : promisesToBeRejected)
promise->reject(Exception { EncodingError, message });
}
inline void ImageLoader::resolveDecodePromises()
{
resolvePromises(m_decodingPromises);
}
inline void ImageLoader::rejectDecodePromises(const char* message)
{
rejectPromises(m_decodingPromises, message);
}
void ImageLoader::notifyFinished(CachedResource& resource, const NetworkLoadMetrics&)
{
ASSERT(m_failedLoadURL.isEmpty());
ASSERT_UNUSED(resource, &resource == m_image.get());
if (m_lazyImageLoadState == LazyImageLoadState::Deferred) {
LazyLoadImageObserver::unobserve(element(), element().document());
m_lazyImageLoadState = LazyImageLoadState::FullImage;
}
m_imageComplete = true;
if (!hasPendingBeforeLoadEvent())
updateRenderer();
if (!m_hasPendingLoadEvent)
return;
if (m_image->resourceError().isAccessControl()) {
URL imageURL = m_image->url();
clearImageWithoutConsideringPendingLoadEvent();
m_hasPendingErrorEvent = true;
errorEventSender().dispatchEventSoon(*this);
auto message = makeString("Cannot load image ", imageURL.string(), " due to access control checks.");
element().document().addConsoleMessage(MessageSource::Security, MessageLevel::Error, message);
if (hasPendingDecodePromises())
rejectDecodePromises("Access control error.");
ASSERT(!m_hasPendingLoadEvent);
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
return;
}
if (m_image->wasCanceled()) {
if (hasPendingDecodePromises())
rejectDecodePromises("Loading was canceled.");
m_hasPendingLoadEvent = false;
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
return;
}
if (hasPendingDecodePromises())
decode();
loadEventSender().dispatchEventSoon(*this);
}
RenderImageResource* ImageLoader::renderImageResource()
{
auto* renderer = element().renderer();
if (!renderer)
return nullptr;
// We don't return style generated image because it doesn't belong to the ImageLoader.
// See <https://bugs.webkit.org/show_bug.cgi?id=42840>
if (is<RenderImage>(*renderer) && !downcast<RenderImage>(*renderer).isGeneratedContent())
return &downcast<RenderImage>(*renderer).imageResource();
if (is<RenderSVGImage>(*renderer))
return &downcast<RenderSVGImage>(*renderer).imageResource();
#if ENABLE(VIDEO)
if (is<RenderVideo>(*renderer))
return &downcast<RenderVideo>(*renderer).imageResource();
#endif
return nullptr;
}
void ImageLoader::updateRenderer()
{
RenderImageResource* imageResource = renderImageResource();
if (!imageResource)
return;
// Only update the renderer if it doesn't have an image or if what we have
// is a complete image. This prevents flickering in the case where a dynamic
// change is happening between two images.
CachedImage* cachedImage = imageResource->cachedImage();
if (m_image != cachedImage && (m_imageComplete || !cachedImage))
imageResource->setCachedImage(m_image.get());
}
void ImageLoader::updatedHasPendingEvent()
{
// If an Element that does image loading is removed from the DOM the load/error event for the image is still observable.
// As long as the ImageLoader is actively loading, the Element itself needs to be ref'ed to keep it from being
// destroyed by DOM manipulation or garbage collection.
// If such an Element wishes for the load to stop when removed from the DOM it needs to stop the ImageLoader explicitly.
bool wasProtected = m_elementIsProtected;
m_elementIsProtected = m_hasPendingLoadEvent || m_hasPendingErrorEvent;
if (wasProtected == m_elementIsProtected)
return;
if (m_elementIsProtected) {
if (m_derefElementTimer.isActive())
m_derefElementTimer.stop();
else
m_protectedElement = &element();
} else {
ASSERT(!m_derefElementTimer.isActive());
m_derefElementTimer.startOneShot(0_s);
}
}
void ImageLoader::decode(Ref<DeferredPromise>&& promise)
{
m_decodingPromises.append(WTFMove(promise));
if (!element().document().domWindow()) {
rejectDecodePromises("Inactive document.");
return;
}
AtomString attr = element().imageSourceURL();
if (stripLeadingAndTrailingHTMLSpaces(attr).isEmpty()) {
rejectDecodePromises("Missing source URL.");
return;
}
if (m_imageComplete)
decode();
}
void ImageLoader::decode()
{
ASSERT(hasPendingDecodePromises());
if (!element().document().domWindow()) {
rejectDecodePromises("Inactive document.");
return;
}
if (!m_image || !m_image->image() || m_image->errorOccurred()) {
rejectDecodePromises("Loading error.");
return;
}
Image* image = m_image->image();
if (!is<BitmapImage>(image)) {
resolveDecodePromises();
return;
}
auto& bitmapImage = downcast<BitmapImage>(*image);
bitmapImage.decode([promises = WTFMove(m_decodingPromises)]() mutable {
resolvePromises(promises);
});
}
void ImageLoader::timerFired()
{
m_protectedElement = nullptr;
}
void ImageLoader::dispatchPendingEvent(ImageEventSender* eventSender)
{
ASSERT(eventSender == &beforeLoadEventSender() || eventSender == &loadEventSender() || eventSender == &errorEventSender());
const AtomString& eventType = eventSender->eventType();
if (eventType == eventNames().beforeloadEvent)
dispatchPendingBeforeLoadEvent();
if (eventType == eventNames().loadEvent)
dispatchPendingLoadEvent();
if (eventType == eventNames().errorEvent)
dispatchPendingErrorEvent();
}
void ImageLoader::dispatchPendingBeforeLoadEvent()
{
if (!m_hasPendingBeforeLoadEvent)
return;
if (!m_image)
return;
if (!element().document().hasLivingRenderTree())
return;
m_hasPendingBeforeLoadEvent = false;
Ref<Document> originalDocument = element().document();
if (element().dispatchBeforeLoadEvent(m_image->url().string())) {
bool didEventListenerDisconnectThisElement = !element().isConnected() || &element().document() != originalDocument.ptr();
if (didEventListenerDisconnectThisElement)
return;
updateRenderer();
return;
}
if (m_image) {
m_image->removeClient(*this);
m_image = nullptr;
}
loadEventSender().cancelEvent(*this);
m_hasPendingLoadEvent = false;
if (is<HTMLObjectElement>(element()))
downcast<HTMLObjectElement>(element()).renderFallbackContent();
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
}
void ImageLoader::dispatchPendingLoadEvent()
{
if (!m_hasPendingLoadEvent)
return;
if (!m_image)
return;
m_hasPendingLoadEvent = false;
if (element().document().hasLivingRenderTree())
dispatchLoadEvent();
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
}
void ImageLoader::dispatchPendingErrorEvent()
{
if (!m_hasPendingErrorEvent)
return;
m_hasPendingErrorEvent = false;
if (element().document().hasLivingRenderTree())
element().dispatchEvent(Event::create(eventNames().errorEvent, Event::CanBubble::No, Event::IsCancelable::No));
// Only consider updating the protection ref-count of the Element immediately before returning
// from this function as doing so might result in the destruction of this ImageLoader.
updatedHasPendingEvent();
}
void ImageLoader::dispatchPendingBeforeLoadEvents(Page* page)
{
beforeLoadEventSender().dispatchPendingEvents(page);
}
void ImageLoader::dispatchPendingLoadEvents(Page* page)
{
loadEventSender().dispatchPendingEvents(page);
}
void ImageLoader::dispatchPendingErrorEvents(Page* page)
{
errorEventSender().dispatchPendingEvents(page);
}
void ImageLoader::elementDidMoveToNewDocument(Document& oldDocument)
{
clearFailedLoadURL();
clearImage();
if (isDeferred())
LazyLoadImageObserver::unobserve(element(), oldDocument);
m_lazyImageLoadState = LazyImageLoadState::None;
}
inline void ImageLoader::clearFailedLoadURL()
{
m_failedLoadURL = nullAtom();
}
void ImageLoader::loadDeferredImage()
{
if (m_lazyImageLoadState != LazyImageLoadState::Deferred)
return;
m_lazyImageLoadState = LazyImageLoadState::LoadImmediately;
updateFromElement(RelevantMutation::No);
}
}