C++ FrameLoader::cancelledError方法代码示例

// Cancels the data source's pending loads.  Conceptually, a data source only loads
// one document at a time, but one document may have many related resources. 
// stopLoading will stop all loads initiated by the data source, 
// but not loads initiated by child frames' data sources -- that's the WebFrame's job.
void DocumentLoader::stopLoading()
{
    // In some rare cases, calling FrameLoader::stopLoading could set m_loading to false.
    // (This can happen when there's a single XMLHttpRequest currently loading and stopLoading causes it
    // to stop loading. Because of this, we need to save it so we don't return early.
    bool loading = m_loading;
    
    if (m_committed) {
        // Attempt to stop the frame if the document loader is loading, or if it is done loading but
        // still  parsing. Failure to do so can cause a world leak.
        Document* doc = m_frame->document();
        
        if (loading || doc->parsing())
            m_frame->loader()->stopLoading(UnloadEventPolicyNone);
    }

    // Always cancel multipart loaders
    cancelAll(m_multipartSubresourceLoaders);

    // Appcache uses ResourceHandle directly, DocumentLoader doesn't count these loads.
    m_applicationCacheHost->stopLoadingInFrame(m_frame);

    if (!loading) {
        // If something above restarted loading we might run into mysterious crashes like 
        // https://bugs.webkit.org/show_bug.cgi?id=62764 and <rdar://problem/9328684>
        ASSERT(!m_loading);
        return;
    }

    // We might run in to infinite recursion if we're stopping loading as the result of 
    // detaching from the frame, so break out of that recursion here.
    // See <rdar://problem/9673866> for more details.
    if (m_isStopping)
        return;
    
    RefPtr<Frame> protectFrame(m_frame);
    RefPtr<DocumentLoader> protectLoader(this);

    m_isStopping = true;

    FrameLoader* frameLoader = DocumentLoader::frameLoader();
    
    if (m_mainResourceLoader)
        // Stop the main resource loader and let it send the cancelled message.
        m_mainResourceLoader->cancel();
    else if (!m_subresourceLoaders.isEmpty())
        // The main resource loader already finished loading. Set the cancelled error on the 
        // document and let the subresourceLoaders send individual cancelled messages below.
        setMainDocumentError(frameLoader->cancelledError(m_request));
    else
        // If there are no resource loaders, we need to manufacture a cancelled message.
        // (A back/forward navigation has no resource loaders because its resources are cached.)
        mainReceivedError(frameLoader->cancelledError(m_request), true);
    
    stopLoadingSubresources();
    stopLoadingPlugIns();
    
    m_isStopping = false;
}