C++ ApplicationCache::resourceForURL方法代码示例

bool ApplicationCacheHost::shouldLoadResourceFromApplicationCache(const ResourceRequest& originalRequest, ApplicationCacheResource*& resource)
{
    ApplicationCache* cache = applicationCache();
    if (!cache || !cache->isComplete())
        return false;

    ResourceRequest request(originalRequest);
    if (Frame* loaderFrame = m_documentLoader.frame()) {
        if (Document* document = loaderFrame->document())
            document->contentSecurityPolicy()->upgradeInsecureRequestIfNeeded(request, ContentSecurityPolicy::InsecureRequestType::Load);
    }
    
    // If the resource is not to be fetched using the HTTP GET mechanism or equivalent, or if its URL has a different
    // <scheme> component than the application cache's manifest, then fetch the resource normally.
    if (!ApplicationCache::requestIsHTTPOrHTTPSGet(request) || !equalIgnoringASCIICase(request.url().protocol(), cache->manifestResource()->url().protocol()))
        return false;

    // If the resource's URL is an master entry, the manifest, an explicit entry, or a fallback entry
    // in the application cache, then get the resource from the cache (instead of fetching it).
    resource = cache->resourceForURL(request.url());

    // Resources that match fallback namespaces or online whitelist entries are fetched from the network,
    // unless they are also cached.
    if (!resource && (cache->allowsAllNetworkRequests() || cache->urlMatchesFallbackNamespace(request.url()) || cache->isURLInOnlineWhitelist(request.url())))
        return false;

    // Resources that are not present in the manifest will always fail to load (at least, after the
    // cache has been primed the first time), making the testing of offline applications simpler.
    return true;
}

bool DocumentLoader::shouldLoadResourceFromApplicationCache(const ResourceRequest& request, ApplicationCacheResource*& resource)
{
    ApplicationCache* cache = topLevelApplicationCache();    
    if (!cache)
        return false;
    
    // If the resource is not a HTTP/HTTPS GET, then abort
    if (!ApplicationCache::requestIsHTTPOrHTTPSGet(request))
        return false;
    
    if (cache->isURLInOnlineWhitelist(request.url()))
        return false;
    
    resource = cache->resourceForURL(request.url());
    
    // Don't load foreign resources.
    if (resource && (resource->type() & ApplicationCacheResource::Foreign))
        resource = 0;
    
    return true;
}

bool DocumentLoader::shouldLoadResourceFromApplicationCache(const ResourceRequest& request, ApplicationCacheResource*& resource)
{
    ApplicationCache* cache = applicationCache();
    if (!cache)
        return false;

    // If the resource is not a HTTP/HTTPS GET, then abort
    if (!ApplicationCache::requestIsHTTPOrHTTPSGet(request))
        return false;

    // If the resource's URL is an master entry, the manifest, an explicit entry, a fallback entry, or a dynamic entry
    // in the application cache, then get the resource from the cache (instead of fetching it).
    resource = cache->resourceForURL(request.url());

    // Resources that match fallback namespaces or online whitelist entries are fetched from the network,
    // unless they are also cached.
    if (!resource && (cache->urlMatchesFallbackNamespace(request.url()) || cache->isURLInOnlineWhitelist(request.url())))
        return false;

    // Resources that are not present in the manifest will always fail to load (at least, after the
    // cache has been primed the first time), making the testing of offline applications simpler.
    return true;
}

void ApplicationCacheGroup::selectCache(Frame* frame, const KURL& manifestURL)
{
    ASSERT(frame && frame->page());
    
    if (!frame->settings()->offlineWebApplicationCacheEnabled())
        return;
    
    DocumentLoader* documentLoader = frame->loader()->documentLoader();
    ASSERT(!documentLoader->applicationCache());

    if (manifestURL.isNull()) {
        selectCacheWithoutManifestURL(frame);        
        return;
    }
    
    ApplicationCache* mainResourceCache = documentLoader->mainResourceApplicationCache();
    
    if (mainResourceCache) {
        if (manifestURL == mainResourceCache->group()->m_manifestURL) {
            mainResourceCache->group()->associateDocumentLoaderWithCache(documentLoader, mainResourceCache);
            mainResourceCache->group()->update(frame);
        } else {
            // The main resource was loaded from cache, so the cache must have an entry for it. Mark it as foreign.
            ApplicationCacheResource* resource = mainResourceCache->resourceForURL(documentLoader->url());
            bool inStorage = resource->storageID();
            resource->addType(ApplicationCacheResource::Foreign);
            if (inStorage)
                cacheStorage().storeUpdatedType(resource, mainResourceCache);

            // Restart the current navigation from the top of the navigation algorithm, undoing any changes that were made
            // as part of the initial load.
            // The navigation will not result in the same resource being loaded, because "foreign" entries are never picked during navigation.
            frame->loader()->scheduleLocationChange(documentLoader->url(), frame->loader()->referrer(), true);
        }
        
        return;
    }
    
    // The resource was loaded from the network, check if it is a HTTP/HTTPS GET.    
    const ResourceRequest& request = frame->loader()->activeDocumentLoader()->request();

    if (!ApplicationCache::requestIsHTTPOrHTTPSGet(request)) {
        selectCacheWithoutManifestURL(frame);
        return;
    }

    // Check that the resource URL has the same scheme/host/port as the manifest URL.
    if (!protocolHostAndPortAreEqual(manifestURL, request.url())) {
        selectCacheWithoutManifestURL(frame);
        return;
    }
            
    ApplicationCacheGroup* group = cacheStorage().findOrCreateCacheGroup(manifestURL);
            
    if (ApplicationCache* cache = group->newestCache()) {
        ASSERT(cache->manifestResource());
                
        group->associateDocumentLoaderWithCache(frame->loader()->documentLoader(), cache);
              
        if (!frame->loader()->documentLoader()->isLoadingMainResource())
            group->finishedLoadingMainResource(frame->loader()->documentLoader());

        group->update(frame);
    } else {
        bool isUpdating = group->m_cacheBeingUpdated;
                
        if (!isUpdating)
            group->m_cacheBeingUpdated = ApplicationCache::create();
        documentLoader->setCandidateApplicationCacheGroup(group);
        group->m_cacheCandidates.add(documentLoader);

        const KURL& url = frame->loader()->documentLoader()->originalURL();
                
        unsigned type = 0;

        // If the resource has already been downloaded, remove it so that it will be replaced with the implicit resource
        if (isUpdating)
            type = group->m_cacheBeingUpdated->removeResource(url);
               
        // Add the main resource URL as an implicit entry.
        group->addEntry(url, type | ApplicationCacheResource::Implicit);

        if (!frame->loader()->documentLoader()->isLoadingMainResource())
            group->finishedLoadingMainResource(frame->loader()->documentLoader());
                
        if (!isUpdating)
            group->update(frame);                
    }               
}