*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/rendering/FlowThreadController.cpp

-/*
- * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above
- *    copyright notice, this list of conditions and the following
- *    disclaimer.
- * 2. Redistributions in binary form must reproduce the above
- *    copyright notice, this list of conditions and the following
- *    disclaimer in the documentation and/or other materials
- *    provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
- * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
- * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
- * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include "config.h"
-
-#include "core/rendering/FlowThreadController.h"
-
-#include "core/dom/NamedFlowCollection.h"
-#include "core/rendering/RenderFlowThread.h"
-#include "core/rendering/RenderNamedFlowThread.h"
-#include "wtf/text/AtomicString.h"
-
-namespace WebCore {
-
-PassOwnPtr<FlowThreadController> FlowThreadController::create(RenderView* view)
-{
-    return adoptPtr(new FlowThreadController(view));
-}
-
-FlowThreadController::FlowThreadController(RenderView* view)
-    : m_view(view)
-    , m_currentRenderFlowThread(0)
-    , m_isRenderNamedFlowThreadOrderDirty(false)
-    , m_flowThreadsWithAutoLogicalHeightRegions(0)
-{
-}
-
-FlowThreadController::~FlowThreadController()
-{
-}
-
-RenderNamedFlowThread* FlowThreadController::ensureRenderFlowThreadWithName(const AtomicString& name)
-{
-    if (!m_renderNamedFlowThreadList)
-        m_renderNamedFlowThreadList = adoptPtr(new RenderNamedFlowThreadList());
-    else {
-        for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-            RenderNamedFlowThread* flowRenderer = *iter;
-            if (flowRenderer->flowThreadName() == name)
-                return flowRenderer;
-        }
-    }
-
-    NamedFlowCollection* namedFlows = m_view->document().namedFlows();
-
-    // Sanity check for the absence of a named flow in the "CREATED" state with the same name.
-    ASSERT(!namedFlows->flowByName(name));
-
-    RenderNamedFlowThread* flowRenderer = RenderNamedFlowThread::createAnonymous(&m_view->document(), namedFlows->ensureFlowWithName(name));
-    flowRenderer->setStyle(RenderFlowThread::createFlowThreadStyle(m_view->style()));
-    m_renderNamedFlowThreadList->add(flowRenderer);
-
-    // Keep the flow renderer as a child of RenderView.
-    m_view->addChild(flowRenderer);
-
-    setIsRenderNamedFlowThreadOrderDirty(true);
-
-    return flowRenderer;
-}
-
-void FlowThreadController::styleDidChange()
-{
-    RenderStyle* viewStyle = m_view->style();
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        flowRenderer->setStyle(RenderFlowThread::createFlowThreadStyle(viewStyle));
-    }
-}
-
-void FlowThreadController::layoutRenderNamedFlowThreads()
-{
-    updateFlowThreadsChainIfNecessary();
-
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        flowRenderer->layoutIfNeeded();
-    }
-}
-
-void FlowThreadController::registerNamedFlowContentNode(Node* contentNode, RenderNamedFlowThread* namedFlow)
-{
-    ASSERT(contentNode && contentNode->isElementNode());
-    ASSERT(namedFlow);
-    ASSERT(!m_mapNamedFlowContentNodes.contains(contentNode));
-    ASSERT(!namedFlow->hasContentNode(contentNode));
-    m_mapNamedFlowContentNodes.add(contentNode, namedFlow);
-    namedFlow->registerNamedFlowContentNode(contentNode);
-}
-
-void FlowThreadController::unregisterNamedFlowContentNode(Node* contentNode)
-{
-    ASSERT(contentNode && contentNode->isElementNode());
-    HashMap<const Node*, RenderNamedFlowThread*>::iterator it = m_mapNamedFlowContentNodes.find(contentNode);
-    ASSERT_WITH_SECURITY_IMPLICATION(it != m_mapNamedFlowContentNodes.end());
-    ASSERT(it->value);
-    ASSERT(it->value->hasContentNode(contentNode));
-    it->value->unregisterNamedFlowContentNode(contentNode);
-    m_mapNamedFlowContentNodes.remove(contentNode);
-}
-
-void FlowThreadController::updateFlowThreadsChainIfNecessary()
-{
-    ASSERT(m_renderNamedFlowThreadList);
-    ASSERT(isAutoLogicalHeightRegionsCountConsistent());
-
-    // Remove the left-over flow threads.
-    RenderNamedFlowThreadList toRemoveList;
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        if (flowRenderer->isMarkedForDestruction())
-            toRemoveList.add(flowRenderer);
-    }
-
-    if (toRemoveList.size() > 0)
-        setIsRenderNamedFlowThreadOrderDirty(true);
-
-    for (RenderNamedFlowThreadList::iterator iter = toRemoveList.begin(); iter != toRemoveList.end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        m_renderNamedFlowThreadList->remove(flowRenderer);
-        flowRenderer->destroy();
-    }
-
-    if (isRenderNamedFlowThreadOrderDirty()) {
-        // Arrange the thread list according to dependencies.
-        RenderNamedFlowThreadList sortedList;
-        for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-            RenderNamedFlowThread* flowRenderer = *iter;
-            if (sortedList.contains(flowRenderer))
-                continue;
-            flowRenderer->pushDependencies(sortedList);
-            sortedList.add(flowRenderer);
-        }
-        m_renderNamedFlowThreadList->swap(sortedList);
-        setIsRenderNamedFlowThreadOrderDirty(false);
-    }
-}
-
-bool FlowThreadController::updateFlowThreadsNeedingLayout()
-{
-    bool needsTwoPassLayout = false;
-
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        ASSERT(!flowRenderer->needsTwoPhasesLayout());
-        flowRenderer->setInConstrainedLayoutPhase(false);
-        if (flowRenderer->needsLayout() && flowRenderer->hasAutoLogicalHeightRegions())
-            needsTwoPassLayout = true;
-    }
-
-    if (needsTwoPassLayout)
-        resetFlowThreadsWithAutoHeightRegions();
-
-    return needsTwoPassLayout;
-}
-
-bool FlowThreadController::updateFlowThreadsNeedingTwoStepLayout()
-{
-    bool needsTwoPassLayout = false;
-
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        if (flowRenderer->needsTwoPhasesLayout()) {
-            needsTwoPassLayout = true;
-            break;
-        }
-    }
-
-    if (needsTwoPassLayout)
-        resetFlowThreadsWithAutoHeightRegions();
-
-    return needsTwoPassLayout;
-}
-
-void FlowThreadController::resetFlowThreadsWithAutoHeightRegions()
-{
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        if (flowRenderer->hasAutoLogicalHeightRegions()) {
-            flowRenderer->markAutoLogicalHeightRegionsForLayout();
-            flowRenderer->invalidateRegions();
-        }
-    }
-}
-
-void FlowThreadController::updateFlowThreadsIntoConstrainedPhase()
-{
-    // Walk the flow chain in reverse order to update the auto-height regions and compute correct sizes for the containing regions. Only after this we can
-    // set the flow in the constrained layout phase.
-    for (RenderNamedFlowThreadList::reverse_iterator iter = m_renderNamedFlowThreadList->rbegin(); iter != m_renderNamedFlowThreadList->rend(); ++iter) {
-        RenderNamedFlowThread* flowRenderer = *iter;
-        ASSERT(!flowRenderer->hasRegions() || flowRenderer->hasValidRegionInfo());
-        flowRenderer->layoutIfNeeded();
-        if (flowRenderer->hasAutoLogicalHeightRegions()) {
-            ASSERT(flowRenderer->needsTwoPhasesLayout());
-            flowRenderer->markAutoLogicalHeightRegionsForLayout();
-        }
-        flowRenderer->setInConstrainedLayoutPhase(true);
-        flowRenderer->clearNeedsTwoPhasesLayout();
-    }
-}
-
-bool FlowThreadController::isContentNodeRegisteredWithAnyNamedFlow(const Node* contentNode) const
-{
-    return m_mapNamedFlowContentNodes.contains(contentNode);
-}
-
-#ifndef NDEBUG
-bool FlowThreadController::isAutoLogicalHeightRegionsCountConsistent() const
-{
-    if (!hasRenderNamedFlowThreads())
-        return !hasFlowThreadsWithAutoLogicalHeightRegions();
-
-    for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
-        if (!(*iter)->isAutoLogicalHeightRegionsCountConsistent())
-            return false;
-    }
-
-    return true;
-}
-#endif
-
-} // namespace WebCore