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      1 /*
      2  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
      3  *
      4  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
      5  *
      6  * Other contributors:
      7  *   Robert O'Callahan <roc+@cs.cmu.edu>
      8  *   David Baron <dbaron (at) fas.harvard.edu>
      9  *   Christian Biesinger <cbiesinger (at) web.de>
     10  *   Randall Jesup <rjesup (at) wgate.com>
     11  *   Roland Mainz <roland.mainz (at) informatik.med.uni-giessen.de>
     12  *   Josh Soref <timeless (at) mac.com>
     13  *   Boris Zbarsky <bzbarsky (at) mit.edu>
     14  *
     15  * This library is free software; you can redistribute it and/or
     16  * modify it under the terms of the GNU Lesser General Public
     17  * License as published by the Free Software Foundation; either
     18  * version 2.1 of the License, or (at your option) any later version.
     19  *
     20  * This library is distributed in the hope that it will be useful,
     21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     23  * Lesser General Public License for more details.
     24  *
     25  * You should have received a copy of the GNU Lesser General Public
     26  * License along with this library; if not, write to the Free Software
     27  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     28  *
     29  * Alternatively, the contents of this file may be used under the terms
     30  * of either the Mozilla Public License Version 1.1, found at
     31  * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
     32  * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
     33  * (the "GPL"), in which case the provisions of the MPL or the GPL are
     34  * applicable instead of those above.  If you wish to allow use of your
     35  * version of this file only under the terms of one of those two
     36  * licenses (the MPL or the GPL) and not to allow others to use your
     37  * version of this file under the LGPL, indicate your decision by
     38  * deletingthe provisions above and replace them with the notice and
     39  * other provisions required by the MPL or the GPL, as the case may be.
     40  * If you do not delete the provisions above, a recipient may use your
     41  * version of this file under any of the LGPL, the MPL or the GPL.
     42  */
     43 
     44 #include "config.h"
     45 #include "core/rendering/RenderLayerStackingNode.h"
     46 
     47 #include "core/rendering/RenderLayer.h"
     48 #include "core/rendering/RenderView.h"
     49 #include "core/rendering/compositing/RenderLayerCompositor.h"
     50 #include "public/platform/Platform.h"
     51 
     52 namespace blink {
     53 
     54 // FIXME: This should not require RenderLayer. There is currently a cycle where
     55 // in order to determine if we shoulBeNormalFlowOnly() we have to ask the render
     56 // layer about some of its state.
     57 RenderLayerStackingNode::RenderLayerStackingNode(RenderLayer* layer)
     58     : m_layer(layer)
     59     , m_normalFlowListDirty(true)
     60 #if ENABLE(ASSERT)
     61     , m_layerListMutationAllowed(true)
     62     , m_stackingParent(0)
     63 #endif
     64 {
     65     m_isNormalFlowOnly = shouldBeNormalFlowOnly();
     66 
     67     // Non-stacking contexts should have empty z-order lists. As this is already the case,
     68     // there is no need to dirty / recompute these lists.
     69     m_zOrderListsDirty = isStackingContext();
     70 }
     71 
     72 RenderLayerStackingNode::~RenderLayerStackingNode()
     73 {
     74 #if ENABLE(ASSERT)
     75     if (!renderer()->documentBeingDestroyed()) {
     76         ASSERT(!isInStackingParentZOrderLists());
     77         ASSERT(!isInStackingParentNormalFlowList());
     78 
     79         updateStackingParentForZOrderLists(0);
     80         updateStackingParentForNormalFlowList(0);
     81     }
     82 #endif
     83 }
     84 
     85 // Helper for the sorting of layers by z-index.
     86 static inline bool compareZIndex(RenderLayerStackingNode* first, RenderLayerStackingNode* second)
     87 {
     88     return first->zIndex() < second->zIndex();
     89 }
     90 
     91 RenderLayerCompositor* RenderLayerStackingNode::compositor() const
     92 {
     93     ASSERT(renderer()->view());
     94     return renderer()->view()->compositor();
     95 }
     96 
     97 void RenderLayerStackingNode::dirtyZOrderLists()
     98 {
     99     ASSERT(m_layerListMutationAllowed);
    100     ASSERT(isStackingContext());
    101 
    102 #if ENABLE(ASSERT)
    103     updateStackingParentForZOrderLists(0);
    104 #endif
    105 
    106     if (m_posZOrderList)
    107         m_posZOrderList->clear();
    108     if (m_negZOrderList)
    109         m_negZOrderList->clear();
    110     m_zOrderListsDirty = true;
    111 
    112     if (!renderer()->documentBeingDestroyed())
    113         compositor()->setNeedsCompositingUpdate(CompositingUpdateRebuildTree);
    114 }
    115 
    116 void RenderLayerStackingNode::dirtyStackingContextZOrderLists()
    117 {
    118     if (RenderLayerStackingNode* stackingNode = ancestorStackingContextNode())
    119         stackingNode->dirtyZOrderLists();
    120 }
    121 
    122 void RenderLayerStackingNode::dirtyNormalFlowList()
    123 {
    124     ASSERT(m_layerListMutationAllowed);
    125 
    126 #if ENABLE(ASSERT)
    127     updateStackingParentForNormalFlowList(0);
    128 #endif
    129 
    130     if (m_normalFlowList)
    131         m_normalFlowList->clear();
    132     m_normalFlowListDirty = true;
    133 
    134     if (!renderer()->documentBeingDestroyed())
    135         compositor()->setNeedsCompositingUpdate(CompositingUpdateRebuildTree);
    136 }
    137 
    138 void RenderLayerStackingNode::rebuildZOrderLists()
    139 {
    140     ASSERT(m_layerListMutationAllowed);
    141     ASSERT(isDirtyStackingContext());
    142 
    143     for (RenderLayer* child = layer()->firstChild(); child; child = child->nextSibling()) {
    144         if (!layer()->reflectionInfo() || layer()->reflectionInfo()->reflectionLayer() != child)
    145             child->stackingNode()->collectLayers(m_posZOrderList, m_negZOrderList);
    146     }
    147 
    148     // Sort the two lists.
    149     if (m_posZOrderList)
    150         std::stable_sort(m_posZOrderList->begin(), m_posZOrderList->end(), compareZIndex);
    151 
    152     if (m_negZOrderList)
    153         std::stable_sort(m_negZOrderList->begin(), m_negZOrderList->end(), compareZIndex);
    154 
    155     // Append layers for top layer elements after normal layer collection, to ensure they are on top regardless of z-indexes.
    156     // The renderers of top layer elements are children of the view, sorted in top layer stacking order.
    157     if (layer()->isRootLayer()) {
    158         RenderView* view = renderer()->view();
    159         for (RenderObject* child = view->firstChild(); child; child = child->nextSibling()) {
    160             Element* childElement = (child->node() && child->node()->isElementNode()) ? toElement(child->node()) : 0;
    161             if (childElement && childElement->isInTopLayer()) {
    162                 RenderLayer* layer = toRenderLayerModelObject(child)->layer();
    163                 // Create the buffer if it doesn't exist yet.
    164                 if (!m_posZOrderList)
    165                     m_posZOrderList = adoptPtr(new Vector<RenderLayerStackingNode*>);
    166                 m_posZOrderList->append(layer->stackingNode());
    167             }
    168         }
    169     }
    170 
    171 #if ENABLE(ASSERT)
    172     updateStackingParentForZOrderLists(this);
    173 #endif
    174 
    175     m_zOrderListsDirty = false;
    176 }
    177 
    178 void RenderLayerStackingNode::updateNormalFlowList()
    179 {
    180     if (!m_normalFlowListDirty)
    181         return;
    182 
    183     ASSERT(m_layerListMutationAllowed);
    184 
    185     for (RenderLayer* child = layer()->firstChild(); child; child = child->nextSibling()) {
    186         if (child->stackingNode()->isNormalFlowOnly() && (!layer()->reflectionInfo() || layer()->reflectionInfo()->reflectionLayer() != child)) {
    187             if (!m_normalFlowList)
    188                 m_normalFlowList = adoptPtr(new Vector<RenderLayerStackingNode*>);
    189             m_normalFlowList->append(child->stackingNode());
    190         }
    191     }
    192 
    193 #if ENABLE(ASSERT)
    194     updateStackingParentForNormalFlowList(this);
    195 #endif
    196 
    197     m_normalFlowListDirty = false;
    198 }
    199 
    200 void RenderLayerStackingNode::collectLayers(OwnPtr<Vector<RenderLayerStackingNode*> >& posBuffer, OwnPtr<Vector<RenderLayerStackingNode*> >& negBuffer)
    201 {
    202     if (layer()->isInTopLayer())
    203         return;
    204 
    205     if (!isNormalFlowOnly()) {
    206         OwnPtr<Vector<RenderLayerStackingNode*> >& buffer = (zIndex() >= 0) ? posBuffer : negBuffer;
    207         if (!buffer)
    208             buffer = adoptPtr(new Vector<RenderLayerStackingNode*>);
    209         buffer->append(this);
    210     }
    211 
    212     if (!isStackingContext()) {
    213         for (RenderLayer* child = layer()->firstChild(); child; child = child->nextSibling()) {
    214             if (!layer()->reflectionInfo() || layer()->reflectionInfo()->reflectionLayer() != child)
    215                 child->stackingNode()->collectLayers(posBuffer, negBuffer);
    216         }
    217     }
    218 }
    219 
    220 #if ENABLE(ASSERT)
    221 bool RenderLayerStackingNode::isInStackingParentZOrderLists() const
    222 {
    223     if (!m_stackingParent || m_stackingParent->zOrderListsDirty())
    224         return false;
    225 
    226     if (m_stackingParent->posZOrderList() && m_stackingParent->posZOrderList()->find(this) != kNotFound)
    227         return true;
    228 
    229     if (m_stackingParent->negZOrderList() && m_stackingParent->negZOrderList()->find(this) != kNotFound)
    230         return true;
    231 
    232     return false;
    233 }
    234 
    235 bool RenderLayerStackingNode::isInStackingParentNormalFlowList() const
    236 {
    237     if (!m_stackingParent || m_stackingParent->normalFlowListDirty())
    238         return false;
    239 
    240     return (m_stackingParent->normalFlowList() && m_stackingParent->normalFlowList()->find(this) != kNotFound);
    241 }
    242 
    243 void RenderLayerStackingNode::updateStackingParentForZOrderLists(RenderLayerStackingNode* stackingParent)
    244 {
    245     if (m_posZOrderList) {
    246         for (size_t i = 0; i < m_posZOrderList->size(); ++i)
    247             m_posZOrderList->at(i)->setStackingParent(stackingParent);
    248     }
    249 
    250     if (m_negZOrderList) {
    251         for (size_t i = 0; i < m_negZOrderList->size(); ++i)
    252             m_negZOrderList->at(i)->setStackingParent(stackingParent);
    253     }
    254 }
    255 
    256 void RenderLayerStackingNode::updateStackingParentForNormalFlowList(RenderLayerStackingNode* stackingParent)
    257 {
    258     if (m_normalFlowList) {
    259         for (size_t i = 0; i < m_normalFlowList->size(); ++i)
    260             m_normalFlowList->at(i)->setStackingParent(stackingParent);
    261     }
    262 }
    263 #endif
    264 
    265 void RenderLayerStackingNode::updateLayerListsIfNeeded()
    266 {
    267     updateZOrderLists();
    268     updateNormalFlowList();
    269 
    270     if (!layer()->reflectionInfo())
    271         return;
    272 
    273     RenderLayer* reflectionLayer = layer()->reflectionInfo()->reflectionLayer();
    274     reflectionLayer->stackingNode()->updateZOrderLists();
    275     reflectionLayer->stackingNode()->updateNormalFlowList();
    276 }
    277 
    278 void RenderLayerStackingNode::updateStackingNodesAfterStyleChange(const RenderStyle* oldStyle)
    279 {
    280     bool wasStackingContext = oldStyle ? !oldStyle->hasAutoZIndex() : false;
    281     int oldZIndex = oldStyle ? oldStyle->zIndex() : 0;
    282 
    283     bool isStackingContext = this->isStackingContext();
    284     if (isStackingContext == wasStackingContext && oldZIndex == zIndex())
    285         return;
    286 
    287     dirtyStackingContextZOrderLists();
    288 
    289     if (isStackingContext)
    290         dirtyZOrderLists();
    291     else
    292         clearZOrderLists();
    293 }
    294 
    295 // FIXME: Rename shouldBeNormalFlowOnly to something more accurate now that CSS
    296 // 2.1 defines the term "normal flow".
    297 bool RenderLayerStackingNode::shouldBeNormalFlowOnly() const
    298 {
    299     return !isStackingContext() && !renderer()->isPositioned();
    300 }
    301 
    302 void RenderLayerStackingNode::updateIsNormalFlowOnly()
    303 {
    304     bool isNormalFlowOnly = shouldBeNormalFlowOnly();
    305     if (isNormalFlowOnly == this->isNormalFlowOnly())
    306         return;
    307 
    308     m_isNormalFlowOnly = isNormalFlowOnly;
    309     if (RenderLayer* p = layer()->parent())
    310         p->stackingNode()->dirtyNormalFlowList();
    311     dirtyStackingContextZOrderLists();
    312 }
    313 
    314 RenderLayerStackingNode* RenderLayerStackingNode::ancestorStackingContextNode() const
    315 {
    316     for (RenderLayer* ancestor = layer()->parent(); ancestor; ancestor = ancestor->parent()) {
    317         RenderLayerStackingNode* stackingNode = ancestor->stackingNode();
    318         if (stackingNode->isStackingContext())
    319             return stackingNode;
    320     }
    321     return 0;
    322 }
    323 
    324 RenderLayerModelObject* RenderLayerStackingNode::renderer() const
    325 {
    326     return m_layer->renderer();
    327 }
    328 
    329 } // namespace blink
    330