C++ ImageResource::removeClient方法代码示例

void ImageLoader::setImageWithoutConsideringPendingLoadEvent(ImageResource* newImage)
{
    ASSERT(m_failedLoadURL.isEmpty());
    ImageResource* oldImage = m_image.get();
    if (newImage != oldImage) {
        sourceImageChanged();
        m_image = newImage;
        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 (newImage)
            newImage->addClient(this);
        if (oldImage)
            oldImage->removeClient(this);
    }

    if (RenderImageResource* imageResource = renderImageResource())
        imageResource->resetAnimation();
}

void ImageLoader::updateFromElement(UpdateFromElementBehavior updateBehavior)
{
    AtomicString imageSourceURL = m_element->imageSourceURL();
    m_suppressErrorEvents = (updateBehavior == UpdateSizeChanged);

    if (updateBehavior == UpdateIgnorePreviousError)
        clearFailedLoadURL();

    if (!m_failedLoadURL.isEmpty() && imageSourceURL == m_failedLoadURL)
        return;

    // If we have a pending task, we have to clear it -- either we're
    // now loading immediately, or we need to reset the task's state.
    if (m_pendingTask) {
        m_pendingTask->clearLoader();
        m_pendingTask.clear();
    }

    KURL url = imageSourceToKURL(imageSourceURL);
    if (shouldLoadImmediately(url)) {
        doUpdateFromElement(DoNotBypassMainWorldCSP, updateBehavior);
        return;
    }
    // Allow the idiom "img.src=''; img.src='.." to clear down the image before
    // an asynchronous load completes.
    if (imageSourceURL.isEmpty()) {
        ImageResource* image = m_image.get();
        if (image)
            image->removeClient(this);
        m_image = nullptr;
    }

    // Don't load images for inactive documents. We don't want to slow down the
    // raw HTML parsing case by loading images we don't intend to display.
    Document& document = m_element->document();
    if (document.isActive())
        enqueueImageLoadingMicroTask(updateBehavior);
}

void ImageLoader::updateFromElement()
{
    // Don't load images for inactive documents. We don't want to slow down the
    // raw HTML parsing case by loading images we don't intend to display.
    Document& document = m_element->document();
    if (!document.isActive())
        return;

    AtomicString attr = m_element->imageSourceURL();

    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.
    ResourcePtr<ImageResource> newImage = 0;
    if (!attr.isNull() && !stripLeadingAndTrailingHTMLSpaces(attr).isEmpty()) {
        FetchRequest request(ResourceRequest(document.completeURL(sourceURI(attr))), element()->localName());

        AtomicString crossOriginMode = m_element->fastGetAttribute(HTMLNames::crossoriginAttr);
        if (!crossOriginMode.isNull())
            request.setCrossOriginAccessControl(document.securityOrigin(), crossOriginMode);

        if (m_loadManually) {
            bool autoLoadOtherImages = document.fetcher()->autoLoadImages();
            document.fetcher()->setAutoLoadImages(false);
            newImage = new ImageResource(request.resourceRequest());
            newImage->setLoading(true);
            document.fetcher()->m_documentResources.set(newImage->url(), newImage.get());
            document.fetcher()->setAutoLoadImages(autoLoadOtherImages);
        } else {
            newImage = document.fetcher()->fetchImage(request);
        }

        // 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_hasPendingErrorEvent = true;
        errorEventSender().dispatchEventSoon(this);
    }

    ImageResource* oldImage = m_image.get();
    if (newImage != oldImage) {
        sourceImageChanged();

        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 = !m_element->document().isImageDocument() && newImage;
        m_hasPendingLoadEvent = newImage;
        m_imageComplete = !newImage;

        if (newImage) {
            if (!m_element->document().isImageDocument()) {
                if (!m_element->document().hasListenerType(Document::BEFORELOAD_LISTENER))
                    dispatchPendingBeforeLoadEvent();
                else
                    beforeLoadEventSender().dispatchEventSoon(this);
            } else
                updateRenderer();

            // 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);
        } else {
            updateRenderer();
        }

        if (oldImage)
            oldImage->removeClient(this);
    }

    if (RenderImageResource* imageResource = renderImageResource())
        imageResource->resetAnimation();
//.........这里部分代码省略.........

void ImageLoader::doUpdateFromElement(BypassMainWorldBehavior bypassBehavior, UpdateFromElementBehavior updateBehavior)
{
    // FIXME: According to
    // http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content.html#the-img-element:the-img-element-55
    // When "update image" is called due to environment changes and the load fails, onerror should not be called.
    // That is currently not the case.
    //
    // We don't need to call clearLoader here: Either we were called from the
    // task, or our caller updateFromElement cleared the task's loader (and set
    // m_pendingTask to null).
    m_pendingTask.clear();
    // Make sure to only decrement the count when we exit this function
    OwnPtr<IncrementLoadEventDelayCount> loadDelayCounter;
    loadDelayCounter.swap(m_loadDelayCounter);

    Document& document = m_element->document();
    if (!document.isActive())
        return;

    AtomicString imageSourceURL = m_element->imageSourceURL();
    KURL url = imageSourceToKURL(imageSourceURL);
    ResourcePtr<ImageResource> newImage = 0;
    RefPtrWillBeRawPtr<Element> protectElement(m_element.get());
    if (!url.isNull()) {
        // Unlike raw <img>, we block mixed content inside of <picture> or <img srcset>.
        ResourceLoaderOptions resourceLoaderOptions = ResourceFetcher::defaultResourceOptions();
        ResourceRequest resourceRequest(url);
        resourceRequest.setFetchCredentialsMode(WebURLRequest::FetchCredentialsModeSameOrigin);
        if (updateBehavior == UpdateForcedReload) {
            resourceRequest.setCachePolicy(ResourceRequestCachePolicy::ReloadBypassingCache);
            // ImageLoader defers the load of images when in an ImageDocument. Don't defer this load on a forced reload.
            m_loadingImageDocument = false;
        }
        if (isHTMLPictureElement(element()->parentNode()) || !element()->fastGetAttribute(HTMLNames::srcsetAttr).isNull())
            resourceRequest.setRequestContext(WebURLRequest::RequestContextImageSet);
        FetchRequest request(resourceRequest, element()->localName(), resourceLoaderOptions);
        configureRequest(request, bypassBehavior, *m_element, document.clientHintsPreferences());

        // Prevent the immediate creation of a ResourceLoader (and therefore a network
        // request) for ImageDocument loads. In this case, the image contents have already
        // been requested as a main resource and ImageDocumentParser will take care of
        // funneling the main resource bytes into the ImageResource.
        if (m_loadingImageDocument) {
            request.setDefer(FetchRequest::DeferredByClient);
            request.setContentSecurityCheck(DoNotCheckContentSecurityPolicy);
        }

        newImage = ImageResource::fetch(request, document.fetcher());
        if (m_loadingImageDocument && newImage)
            newImage->setLoading(true);

        if (!newImage && !pageIsBeingDismissed(&document)) {
            crossSiteOrCSPViolationOccurred(imageSourceURL);
            dispatchErrorEvent();
        } else {
            clearFailedLoadURL();
        }
    } else {
        if (!imageSourceURL.isNull()) {
            // Fire an error event if the url string is not empty, but the KURL is.
            dispatchErrorEvent();
        }
        noImageResourceToLoad();
    }

    ImageResource* oldImage = m_image.get();
    if (updateBehavior == UpdateSizeChanged && m_element->layoutObject() && m_element->layoutObject()->isImage() && newImage == oldImage) {
        toLayoutImage(m_element->layoutObject())->intrinsicSizeChanged();
    } else {
        if (newImage != oldImage)
            sourceImageChanged();

        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_hasPendingLoadEvent = newImage;
        m_imageComplete = !newImage;

        updateLayoutObject();
        // If newImage exists and is cached, addClient() will result in the load event
        // being queued to fire. Ensure this happens after beforeload is dispatched.
        if (newImage)
            newImage->addClient(this);

        if (oldImage)
            oldImage->removeClient(this);
    }

//.........这里部分代码省略.........

void ImageLoader::doUpdateFromElement(UpdateFromElementBehavior updateBehavior)
{
    // FIXME: According to
    // http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content.html#the-img-element:the-img-element-55
    // When "update image" is called due to environment changes and the load fails, onerror should not be called.
    // That is currently not the case.
    //
    // We don't need to call clearLoader here: Either we were called from the
    // task, or our caller updateFromElement cleared the task's loader (and set
    // m_pendingTask to null).
    m_pendingTask.clear();
    // Make sure to only decrement the count when we exit this function
    OwnPtr<IncrementLoadEventDelayCount> loadDelayCounter;
    loadDelayCounter.swap(m_loadDelayCounter);

    Document& document = m_element->document();
    if (!document.isActive())
        return;

    AtomicString imageSourceURL = m_element->imageSourceURL();
    KURL url = imageSourceToKURL(imageSourceURL);
    ResourcePtr<ImageResource> newImage = 0;
    if (!url.isNull()) {
        // Unlike raw <img>, we block mixed content inside of <picture> or <img srcset>.
        ResourceLoaderOptions resourceLoaderOptions = ResourceFetcher::defaultResourceOptions();
        ResourceRequest resourceRequest(url);
        FetchRequest request(ResourceRequest(url), element()->localName(), resourceLoaderOptions);

        newImage = document.fetcher()->fetchImage(request);

        if (!newImage && !pageIsBeingDismissed(&document))
            crossSiteOrCSPViolationOccured(imageSourceURL);
        else
            clearFailedLoadURL();
    } else if (!imageSourceURL.isNull()) {
        // Fire an error event if the url string is not empty, but the KURL is.
        m_hasPendingErrorEvent = true;
        errorEventSender().dispatchEventSoon(this);
    }

    ImageResource* oldImage = m_image.get();
    if (newImage != oldImage) {
        sourceImageChanged();

        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_hasPendingLoadEvent = newImage;
        m_imageComplete = !newImage;

        updateRenderer();
        // If newImage exists and is cached, addClient() will result in the load event
        // being queued to fire. Ensure this happens after beforeload is dispatched.
        if (newImage)
            newImage->addClient(this);

        if (oldImage)
            oldImage->removeClient(this);
    } else if (updateBehavior == UpdateSizeChanged && m_element->renderer() && m_element->renderer()->isImage()) {
        toRenderImage(m_element->renderer())->intrinsicSizeChanged();
    }

    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();
}