C++ saveScrollPositionAndViewStateToItem函数代码示例

PassRefPtr<HistoryItem> HistoryController::createItemTree(Frame* targetFrame, bool clipAtTarget)
{
    RefPtr<HistoryItem> bfItem = createItem();
    saveScrollPositionAndViewStateToItem(m_previousItem.get());

    if (!clipAtTarget || m_frame != targetFrame) {
        // save frame state for items that aren't loading (khtml doesn't save those)
        saveDocumentState();

        // clipAtTarget is false for navigations within the same document, so
        // we should copy the documentSequenceNumber over to the newly create
        // item.  Non-target items are just clones, and they should therefore
        // preserve the same itemSequenceNumber.
        if (m_previousItem) {
            if (m_frame != targetFrame)
                bfItem->setItemSequenceNumber(m_previousItem->itemSequenceNumber());
            bfItem->setDocumentSequenceNumber(m_previousItem->documentSequenceNumber());
        }

        for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling()) {
            // If the child is a frame corresponding to an <object> element that never loaded,
            // we don't want to create a history item, because that causes fallback content
            // to be ignored on reload.
            FrameLoader* childLoader = child->loader();
            if (childLoader->stateMachine()->startedFirstRealLoad() || !child->ownerElement()->isObjectElement())
                bfItem->addChildItem(childLoader->history()->createItemTree(targetFrame, clipAtTarget));
        }
    }
    // FIXME: Eliminate the isTargetItem flag in favor of itemSequenceNumber.
    if (m_frame == targetFrame)
        bfItem->setIsTargetItem(true);
    return bfItem;
}

void HistoryController::recursiveUpdateForCommit()
{
    // The frame that navigated will now have a null provisional item.
    // Ignore it and its children.
    if (!m_provisionalItem)
        return;

    // For each frame that already had the content the item requested (based on
    // (a matching URL and frame tree snapshot), just restore the scroll position.
    // Save form state (works from currentItem, since m_frameLoadComplete is true)
    if (m_currentItem && itemsAreClones(m_currentItem.get(), m_provisionalItem.get())) {
        ASSERT(m_frameLoadComplete);
        saveDocumentState();
        saveScrollPositionAndViewStateToItem(m_currentItem.get());

        if (FrameView* view = m_frame->view())
            view->setWasScrolledByUser(false);

        // Now commit the provisional item
        m_frameLoadComplete = false;
        m_previousItem = m_currentItem;
        m_currentItem = m_provisionalItem;
        m_provisionalItem = 0;

        // Restore form state (works from currentItem)
        restoreDocumentState();

        // Restore the scroll position (we choose to do this rather than going back to the anchor point)
        restoreScrollPositionAndViewState();
    }

    // Iterate over the rest of the tree
    for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling())
        child->loader()->history()->recursiveUpdateForCommit();
}

void HistoryController::updateForBackForwardNavigation()
{
#if !LOG_DISABLED
    if (m_frame->loader()->documentLoader())
        LOG(History, "WebCoreHistory: Updating History for back/forward navigation in frame %s", m_frame->loader()->documentLoader()->title().utf8().data());
#endif

    // Must grab the current scroll position before disturbing it
    saveScrollPositionAndViewStateToItem(m_previousItem.get());
}

void HistoryController::updateForBackForwardNavigation()
{
    LOG(History, "HistoryController %p updateForBackForwardNavigation: Updating History for back/forward navigation in frame %p (main frame %d) %s", this, &m_frame, m_frame.isMainFrame(), m_frame.loader().documentLoader() ? m_frame.loader().documentLoader()->url().string().utf8().data() : "");

    // Must grab the current scroll position before disturbing it
    if (!m_frameLoadComplete)
        saveScrollPositionAndViewStateToItem(m_previousItem.get());

    // When traversing history, we may end up redirecting to a different URL
    // this time (e.g., due to cookies).  See http://webkit.org/b/49654.
    updateCurrentItem();
}

// The general idea here is to traverse the frame tree and the item tree in parallel,
// tracking whether each frame already has the content the item requests.  If there is
// a match (by URL), we just restore scroll position and recurse.  Otherwise we must
// reload that frame, and all its kids.
void HistoryController::recursiveGoToItem(HistoryItem* item, HistoryItem* fromItem, FrameLoadType type)
{
    ASSERT(item);
    ASSERT(fromItem);

    KURL itemURL = item->url();
    KURL currentURL;
    if (m_frame->loader()->documentLoader())
        currentURL = m_frame->loader()->documentLoader()->url();

    // Always reload the target frame of the item we're going to.  This ensures that we will
    // do -some- load for the transition, which means a proper notification will be posted
    // to the app.
    // The exact URL has to match, including fragment.  We want to go through the _load
    // method, even if to do a within-page navigation.
    // The current frame tree and the frame tree snapshot in the item have to match.
    if (!item->isTargetItem() &&
        itemURL == currentURL &&
        ((m_frame->tree()->name().isEmpty() && item->target().isEmpty()) || m_frame->tree()->name() == item->target()) &&
        childFramesMatchItem(item))
    {
        // This content is good, so leave it alone and look for children that need reloading
        // Save form state (works from currentItem, since prevItem is nil)
        ASSERT(!m_previousItem);
        saveDocumentState();
        saveScrollPositionAndViewStateToItem(m_currentItem.get());

        if (FrameView* view = m_frame->view())
            view->setWasScrolledByUser(false);

        m_currentItem = item;
                
        // Restore form state (works from currentItem)
        restoreDocumentState();
        
        // Restore the scroll position (we choose to do this rather than going back to the anchor point)
        restoreScrollPositionAndViewState();
        
        const HistoryItemVector& childItems = item->children();
        
        int size = childItems.size();
        for (int i = 0; i < size; ++i) {
            String childFrameName = childItems[i]->target();
            HistoryItem* fromChildItem = fromItem->childItemWithTarget(childFrameName);
            ASSERT(fromChildItem || fromItem->isTargetItem());
            Frame* childFrame = m_frame->tree()->child(childFrameName);
            ASSERT(childFrame);
            childFrame->loader()->history()->recursiveGoToItem(childItems[i].get(), fromChildItem, type);
        }
    } else {
        m_frame->loader()->loadItem(item, type);
    }
}

void HistoryController::updateForBackForwardNavigation()
{
#if !LOG_DISABLED
    LOG(History, "WebCoreHistory: Updating History for back/forward navigation in frame %s", m_frame->document()->title().utf8().data());
#endif

    saveScrollPositionAndViewStateToItem(m_previousItem.get());

    // When traversing history, we may end up redirecting to a different URL
    // this time (e.g., due to cookies).  See http://webkit.org/b/49654.
    updateCurrentItem();
}

void HistoryController::updateForBackForwardNavigation()
{
#if !LOG_DISABLED
    if (m_frame.loader().documentLoader())
        LOG(History, "WebCoreHistory: Updating History for back/forward navigation in frame %s", m_frame.loader().documentLoader()->title().string().utf8().data());
#endif

    // Must grab the current scroll position before disturbing it
    if (!m_frameLoadComplete)
        saveScrollPositionAndViewStateToItem(m_previousItem.get());

    // When traversing history, we may end up redirecting to a different URL
    // this time (e.g., due to cookies).  See http://webkit.org/b/49654.
    updateCurrentItem();
}

void HistoryController::updateForReload()
{
#if !LOG_DISABLED
    if (m_frame.loader().documentLoader())
        LOG(History, "WebCoreHistory: Updating History for reload in frame %s", m_frame.loader().documentLoader()->title().string().utf8().data());
#endif

    if (m_currentItem) {
        PageCache::singleton().remove(*m_currentItem);
    
        if (m_frame.loader().loadType() == FrameLoadType::Reload || m_frame.loader().loadType() == FrameLoadType::ReloadFromOrigin)
            saveScrollPositionAndViewStateToItem(m_currentItem.get());

        // Rebuild the history item tree when reloading as trying to re-associate everything is too error-prone.
        m_currentItem->clearChildren();
    }

    // When reloading the page, we may end up redirecting to a different URL
    // this time (e.g., due to cookies).  See http://webkit.org/b/4072.
    updateCurrentItem();
}

PassRefPtr<HistoryItem> HistoryController::createItemTree(Frame* targetFrame, bool clipAtTarget)
{
    RefPtr<HistoryItem> bfItem = createItem(m_frame->tree()->parent() ? true : false);
    if (m_previousItem)
        saveScrollPositionAndViewStateToItem(m_previousItem.get());
    if (!(clipAtTarget && m_frame == targetFrame)) {
        // save frame state for items that aren't loading (khtml doesn't save those)
        saveDocumentState();
        for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling()) {
            FrameLoader* childLoader = child->loader();
            bool hasChildLoaded = childLoader->frameHasLoaded();

            // If the child is a frame corresponding to an <object> element that never loaded,
            // we don't want to create a history item, because that causes fallback content
            // to be ignored on reload.
            
            if (!(!hasChildLoaded && childLoader->isHostedByObjectElement()))
                bfItem->addChildItem(childLoader->history()->createItemTree(targetFrame, clipAtTarget));
        }
    }
    if (m_frame == targetFrame)
        bfItem->setIsTargetItem(true);
    return bfItem;
}