Source/core/paint/DeprecatedPaintLayerStackingNode.h - chromium/blink - Git at Google

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
  *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
  *   Josh Soref <timeless@mac.com>
  *   Boris Zbarsky <bzbarsky@mit.edu>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  * Alternatively, the contents of this file may be used under the terms
  * of either the Mozilla Public License Version 1.1, found at
  * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
  * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
  * (the "GPL"), in which case the provisions of the MPL or the GPL are
  * applicable instead of those above.  If you wish to allow use of your
  * version of this file only under the terms of one of those two
  * licenses (the MPL or the GPL) and not to allow others to use your
  * version of this file under the LGPL, indicate your decision by
  * deletingthe provisions above and replace them with the notice and
  * other provisions required by the MPL or the GPL, as the case may be.
  * If you do not delete the provisions above, a recipient may use your
  * version of this file under any of the LGPL, the MPL or the GPL.
  */

 #ifndef DeprecatedPaintLayerStackingNode_h
 #define DeprecatedPaintLayerStackingNode_h

 #include "core/CoreExport.h"
 #include "core/layout/LayoutBoxModelObject.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/Vector.h"

 namespace blink {

 class DeprecatedPaintLayer;
 class DeprecatedPaintLayerCompositor;
 class ComputedStyle;
 class LayoutBoxModelObject;

 // DeprecatedPaintLayerStackingNode represents anything that is a stacking
 // context or treated as a stacking context.
 //
 // Stacking contexts are the basis for the CSS painting algorithm. The paint
 // order is determined by walking stacking contexts (or elements treated like a
 // stacking context like positioned objects or floats) in an order defined by
 // ‘z-index’. This walk is interleaved with content that is not a stacking.
 // context. See CSS 2.1 appendix E for the actual algorithm
 // http://www.w3.org/TR/CSS21/zindex.html
 // See also DeprecatedPaintLayerPainter (in particular paintLayerContents) for
 // our implementation of the walk.
 //
 // Stacking contexts form a subtree over the layout tree. Ideally we would want
 // objects of this class to be a node in this tree but there are potential
 // issues with stale pointers so we rely on DeprecatedPaintLayer's tree
 // structure.
 //
 // This class's purpose is to represent a node in the stacking context tree
 // (aka paint tree). It currently caches the z-order lists for painting and
 // hit-testing.
 //
 // To implement any z-order list iterations, use
 // DeprecatedPaintLayerStackingNodeIterator and
 // DeprecatedPaintLayerStackingNodeReverseIterator.
 //
 // This class is NOT DEPRECATED, DeprecatedPaintLayer is and we match its
 // naming.
 class CORE_EXPORT DeprecatedPaintLayerStackingNode {
     WTF_MAKE_FAST_ALLOCATED(DeprecatedPaintLayerStackingNode);
     WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNode);
 public:
     explicit DeprecatedPaintLayerStackingNode(DeprecatedPaintLayer*);
     ~DeprecatedPaintLayerStackingNode();

     int zIndex() const { return layoutObject()->style()->zIndex(); }

     bool isStackingContext() const { return layoutObject()->style()->isStackingContext(); }

     // Update our normal and z-index lists.
     void updateLayerListsIfNeeded();

     bool zOrderListsDirty() const { return m_zOrderListsDirty; }
     void dirtyZOrderLists();
     void updateZOrderLists();
     void clearZOrderLists();
     void dirtyStackingContextZOrderLists();

     bool hasPositiveZOrderList() const { return posZOrderList() && posZOrderList()->size(); }
     bool hasNegativeZOrderList() const { return negZOrderList() && negZOrderList()->size(); }

     bool isTreatedAsOrStackingContext() const { return m_isTreatedAsOrStackingContext; }
     void updateIsTreatedAsStackingContext();

     void updateStackingNodesAfterStyleChange(const ComputedStyle* oldStyle);

     DeprecatedPaintLayerStackingNode* ancestorStackingContextNode() const;

     DeprecatedPaintLayer* layer() const { return m_layer; }

 #if ENABLE(ASSERT)
     bool layerListMutationAllowed() const { return m_layerListMutationAllowed; }
     void setLayerListMutationAllowed(bool flag) { m_layerListMutationAllowed = flag; }
 #endif

 private:
     friend class DeprecatedPaintLayerStackingNodeIterator;
     friend class DeprecatedPaintLayerStackingNodeReverseIterator;
     friend class LayoutTreeAsText;

     Vector<DeprecatedPaintLayerStackingNode*>* posZOrderList() const
     {
         ASSERT(!m_zOrderListsDirty);
         ASSERT(isStackingContext() || !m_posZOrderList);
         return m_posZOrderList.get();
     }

     Vector<DeprecatedPaintLayerStackingNode*>* negZOrderList() const
     {
         ASSERT(!m_zOrderListsDirty);
         ASSERT(isStackingContext() || !m_negZOrderList);
         return m_negZOrderList.get();
     }

     void rebuildZOrderLists();
     void collectLayers(OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>>& posZOrderList, OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>>& negZOrderList);

 #if ENABLE(ASSERT)
     bool isInStackingParentZOrderLists() const;
     void updateStackingParentForZOrderLists(DeprecatedPaintLayerStackingNode* stackingParent);
     void setStackingParent(DeprecatedPaintLayerStackingNode* stackingParent) { m_stackingParent = stackingParent; }
 #endif

     bool shouldBeTreatedAsOrStackingContext() const { return layoutObject()->style()->isTreatedAsOrStackingContext(); }

     bool isDirtyStackingContext() const { return m_zOrderListsDirty && isStackingContext(); }

     DeprecatedPaintLayerCompositor* compositor() const;
     // We can't return a LayoutBox as LayoutInline can be a stacking context.
     LayoutBoxModelObject* layoutObject() const;

     DeprecatedPaintLayer* m_layer;

     // m_posZOrderList holds a sorted list of all the descendant nodes within
     // that have z-indices of 0 or greater (auto will count as 0).
     // m_negZOrderList holds descendants within our stacking context with
     // negative z-indices.
     OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_posZOrderList;
     OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_negZOrderList;

     // This boolean caches whether the z-order lists above are dirty.
     // It is only ever set for stacking contexts, as no other element can
     // have z-order lists.
     unsigned m_zOrderListsDirty : 1;

     // This attribute caches whether the element was a stacking context or
     // was treated like a stacking context, so that we can do comparison against
     // it during style change (styleDidChange in particular), as we have lost
     // the previous style information.
     unsigned m_isTreatedAsOrStackingContext: 1;

 #if ENABLE(ASSERT)
     unsigned m_layerListMutationAllowed : 1;
     DeprecatedPaintLayerStackingNode* m_stackingParent;
 #endif
 };

 inline void DeprecatedPaintLayerStackingNode::clearZOrderLists()
 {
     ASSERT(!isStackingContext());

 #if ENABLE(ASSERT)
     updateStackingParentForZOrderLists(0);
 #endif

     m_posZOrderList.clear();
     m_negZOrderList.clear();
 }

 inline void DeprecatedPaintLayerStackingNode::updateZOrderLists()
 {
     if (!m_zOrderListsDirty)
         return;

     if (!isStackingContext()) {
         clearZOrderLists();
         m_zOrderListsDirty = false;
         return;
     }

     rebuildZOrderLists();
 }

 #if ENABLE(ASSERT)
 class LayerListMutationDetector {
 public:
     explicit LayerListMutationDetector(DeprecatedPaintLayerStackingNode* stackingNode)
         : m_stackingNode(stackingNode)
         , m_previousMutationAllowedState(stackingNode->layerListMutationAllowed())
     {
         m_stackingNode->setLayerListMutationAllowed(false);
     }

     ~LayerListMutationDetector()
     {
         m_stackingNode->setLayerListMutationAllowed(m_previousMutationAllowedState);
     }

 private:
     DeprecatedPaintLayerStackingNode* m_stackingNode;
     bool m_previousMutationAllowedState;
 };
 #endif

 } // namespace blink

 #endif // DeprecatedPaintLayerStackingNode_h
	/*
	* Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
	* Copyright (C) 2013 Intel Corporation. All rights reserved.
	*
	* Portions are Copyright (C) 1998 Netscape Communications Corporation.
	*
	* Other contributors:
	* Robert O'Callahan <roc+@cs.cmu.edu>
	* David Baron <dbaron@fas.harvard.edu>
	* Christian Biesinger <cbiesinger@web.de>
	* Randall Jesup <rjesup@wgate.com>
	* Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
	* Josh Soref <timeless@mac.com>
	* Boris Zbarsky <bzbarsky@mit.edu>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*
	* Alternatively, the contents of this file may be used under the terms
	* of either the Mozilla Public License Version 1.1, found at
	* http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
	* License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
	* (the "GPL"), in which case the provisions of the MPL or the GPL are
	* applicable instead of those above. If you wish to allow use of your
	* version of this file only under the terms of one of those two
	* licenses (the MPL or the GPL) and not to allow others to use your
	* version of this file under the LGPL, indicate your decision by
	* deletingthe provisions above and replace them with the notice and
	* other provisions required by the MPL or the GPL, as the case may be.
	* If you do not delete the provisions above, a recipient may use your
	* version of this file under any of the LGPL, the MPL or the GPL.
	*/

	#ifndef DeprecatedPaintLayerStackingNode_h
	#define DeprecatedPaintLayerStackingNode_h

	#include "core/CoreExport.h"
	#include "core/layout/LayoutBoxModelObject.h"
	#include "wtf/Noncopyable.h"
	#include "wtf/OwnPtr.h"
	#include "wtf/Vector.h"

	namespace blink {

	class DeprecatedPaintLayer;
	class DeprecatedPaintLayerCompositor;
	class ComputedStyle;
	class LayoutBoxModelObject;

	// DeprecatedPaintLayerStackingNode represents anything that is a stacking
	// context or treated as a stacking context.
	//
	// Stacking contexts are the basis for the CSS painting algorithm. The paint
	// order is determined by walking stacking contexts (or elements treated like a
	// stacking context like positioned objects or floats) in an order defined by
	// ‘z-index’. This walk is interleaved with content that is not a stacking.
	// context. See CSS 2.1 appendix E for the actual algorithm
	// http://www.w3.org/TR/CSS21/zindex.html
	// See also DeprecatedPaintLayerPainter (in particular paintLayerContents) for
	// our implementation of the walk.
	//
	// Stacking contexts form a subtree over the layout tree. Ideally we would want
	// objects of this class to be a node in this tree but there are potential
	// issues with stale pointers so we rely on DeprecatedPaintLayer's tree
	// structure.
	//
	// This class's purpose is to represent a node in the stacking context tree
	// (aka paint tree). It currently caches the z-order lists for painting and
	// hit-testing.
	//
	// To implement any z-order list iterations, use
	// DeprecatedPaintLayerStackingNodeIterator and
	// DeprecatedPaintLayerStackingNodeReverseIterator.
	//
	// This class is NOT DEPRECATED, DeprecatedPaintLayer is and we match its
	// naming.
	class CORE_EXPORT DeprecatedPaintLayerStackingNode {
	WTF_MAKE_FAST_ALLOCATED(DeprecatedPaintLayerStackingNode);
	WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNode);
	public:
	explicit DeprecatedPaintLayerStackingNode(DeprecatedPaintLayer*);
	~DeprecatedPaintLayerStackingNode();

	int zIndex() const { return layoutObject()->style()->zIndex(); }

	bool isStackingContext() const { return layoutObject()->style()->isStackingContext(); }

	// Update our normal and z-index lists.
	void updateLayerListsIfNeeded();

	bool zOrderListsDirty() const { return m_zOrderListsDirty; }
	void dirtyZOrderLists();
	void updateZOrderLists();
	void clearZOrderLists();
	void dirtyStackingContextZOrderLists();

	bool hasPositiveZOrderList() const { return posZOrderList() && posZOrderList()->size(); }
	bool hasNegativeZOrderList() const { return negZOrderList() && negZOrderList()->size(); }

	bool isTreatedAsOrStackingContext() const { return m_isTreatedAsOrStackingContext; }
	void updateIsTreatedAsStackingContext();

	void updateStackingNodesAfterStyleChange(const ComputedStyle* oldStyle);

	DeprecatedPaintLayerStackingNode* ancestorStackingContextNode() const;

	DeprecatedPaintLayer* layer() const { return m_layer; }

	#if ENABLE(ASSERT)
	bool layerListMutationAllowed() const { return m_layerListMutationAllowed; }
	void setLayerListMutationAllowed(bool flag) { m_layerListMutationAllowed = flag; }
	#endif

	private:
	friend class DeprecatedPaintLayerStackingNodeIterator;
	friend class DeprecatedPaintLayerStackingNodeReverseIterator;
	friend class LayoutTreeAsText;

	Vector<DeprecatedPaintLayerStackingNode> posZOrderList() const
	{
	ASSERT(!m_zOrderListsDirty);
	ASSERT(isStackingContext() \|\| !m_posZOrderList);
	return m_posZOrderList.get();
	}

	Vector<DeprecatedPaintLayerStackingNode> negZOrderList() const
	{
	ASSERT(!m_zOrderListsDirty);
	ASSERT(isStackingContext() \|\| !m_negZOrderList);
	return m_negZOrderList.get();
	}

	void rebuildZOrderLists();
	void collectLayers(OwnPtr<Vector<DeprecatedPaintLayerStackingNode>>& posZOrderList, OwnPtr<Vector<DeprecatedPaintLayerStackingNode>>& negZOrderList);

	#if ENABLE(ASSERT)
	bool isInStackingParentZOrderLists() const;
	void updateStackingParentForZOrderLists(DeprecatedPaintLayerStackingNode* stackingParent);
	void setStackingParent(DeprecatedPaintLayerStackingNode* stackingParent) { m_stackingParent = stackingParent; }
	#endif

	bool shouldBeTreatedAsOrStackingContext() const { return layoutObject()->style()->isTreatedAsOrStackingContext(); }

	bool isDirtyStackingContext() const { return m_zOrderListsDirty && isStackingContext(); }

	DeprecatedPaintLayerCompositor* compositor() const;
	// We can't return a LayoutBox as LayoutInline can be a stacking context.
	LayoutBoxModelObject* layoutObject() const;

	DeprecatedPaintLayer* m_layer;

	// m_posZOrderList holds a sorted list of all the descendant nodes within
	// that have z-indices of 0 or greater (auto will count as 0).
	// m_negZOrderList holds descendants within our stacking context with
	// negative z-indices.
	OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_posZOrderList;
	OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_negZOrderList;

	// This boolean caches whether the z-order lists above are dirty.
	// It is only ever set for stacking contexts, as no other element can
	// have z-order lists.
	unsigned m_zOrderListsDirty : 1;

	// This attribute caches whether the element was a stacking context or
	// was treated like a stacking context, so that we can do comparison against
	// it during style change (styleDidChange in particular), as we have lost
	// the previous style information.
	unsigned m_isTreatedAsOrStackingContext: 1;

	#if ENABLE(ASSERT)
	unsigned m_layerListMutationAllowed : 1;
	DeprecatedPaintLayerStackingNode* m_stackingParent;
	#endif
	};

	inline void DeprecatedPaintLayerStackingNode::clearZOrderLists()
	{
	ASSERT(!isStackingContext());

	#if ENABLE(ASSERT)
	updateStackingParentForZOrderLists(0);
	#endif

	m_posZOrderList.clear();
	m_negZOrderList.clear();
	}

	inline void DeprecatedPaintLayerStackingNode::updateZOrderLists()
	{
	if (!m_zOrderListsDirty)
	return;

	if (!isStackingContext()) {
	clearZOrderLists();
	m_zOrderListsDirty = false;
	return;
	}

	rebuildZOrderLists();
	}

	#if ENABLE(ASSERT)
	class LayerListMutationDetector {
	public:
	explicit LayerListMutationDetector(DeprecatedPaintLayerStackingNode* stackingNode)
	: m_stackingNode(stackingNode)
	, m_previousMutationAllowedState(stackingNode->layerListMutationAllowed())
	{
	m_stackingNode->setLayerListMutationAllowed(false);
	}

	~LayerListMutationDetector()
	{
	m_stackingNode->setLayerListMutationAllowed(m_previousMutationAllowedState);
	}

	private:
	DeprecatedPaintLayerStackingNode* m_stackingNode;
	bool m_previousMutationAllowedState;
	};
	#endif

	} // namespace blink

	#endif // DeprecatedPaintLayerStackingNode_h