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@fas.harvard.edu>
9 *   Christian Biesinger <cbiesinger@web.de>
10 *   Randall Jesup <rjesup@wgate.com>
11 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
12 *   Josh Soref <timeless@mac.com>
13 *   Boris Zbarsky <bzbarsky@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
52namespace 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.
57RenderLayerStackingNode::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
72RenderLayerStackingNode::~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.
86static inline bool compareZIndex(RenderLayerStackingNode* first, RenderLayerStackingNode* second)
87{
88    return first->zIndex() < second->zIndex();
89}
90
91RenderLayerCompositor* RenderLayerStackingNode::compositor() const
92{
93    ASSERT(renderer()->view());
94    return renderer()->view()->compositor();
95}
96
97void 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
116void RenderLayerStackingNode::dirtyStackingContextZOrderLists()
117{
118    if (RenderLayerStackingNode* stackingNode = ancestorStackingContextNode())
119        stackingNode->dirtyZOrderLists();
120}
121
122void 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
138void 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
178void 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
200void 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)
221bool 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
235bool 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
243void 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
256void 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
265void 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
278void 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".
297bool RenderLayerStackingNode::shouldBeNormalFlowOnly() const
298{
299    return !isStackingContext() && !renderer()->isPositioned();
300}
301
302void 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
314RenderLayerStackingNode* 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
324RenderLayerModelObject* RenderLayerStackingNode::renderer() const
325{
326    return m_layer->renderer();
327}
328
329} // namespace blink
330