third_party/WebKit/Source/core/dom/LayoutTreeBuilder.cpp

   1 /*
   2  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
   3  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
   4  *           (C) 2001 Dirk Mueller (mueller@kde.org)
   5  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
   6  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
   7  * Copyright (C) 2011 Google Inc. All rights reserved.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Library General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Library General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Library General Public License
  20  * along with this library; see the file COPYING.LIB.  If not, write to
  21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  22  * Boston, MA 02110-1301, USA.
  23  *
  24  */
  25
  26 #include "config.h"
  27 #include "core/dom/LayoutTreeBuilder.h"
  28
  29 #include "core/HTMLNames.h"
  30 #include "core/SVGNames.h"
  31 #include "core/css/resolver/StyleResolver.h"
  32 #include "core/dom/FirstLetterPseudoElement.h"
  33 #include "core/dom/Fullscreen.h"
  34 #include "core/dom/Node.h"
  35 #include "core/dom/PseudoElement.h"
  36 #include "core/dom/Text.h"
  37 #include "core/dom/shadow/InsertionPoint.h"
  38 #include "core/layout/LayoutFullScreen.h"
  39 #include "core/layout/LayoutObject.h"
  40 #include "core/layout/LayoutText.h"
  41 #include "core/layout/LayoutView.h"
  42 #include "core/svg/SVGElement.h"
  43 #include "platform/RuntimeEnabledFeatures.h"
  44
  45 namespace blink {
  46
  47 LayoutTreeBuilderForElement::LayoutTreeBuilderForElement(Element& element, ComputedStyle* style)
  48     : LayoutTreeBuilder(element, nullptr)
  49     , m_style(style)
  50 {
  51     ASSERT(!isActiveInsertionPoint(element));
  52     if (element.isFirstLetterPseudoElement()) {
  53         if (LayoutObject* nextLayoutObject = FirstLetterPseudoElement::firstLetterTextLayoutObject(element))
  54             m_layoutObjectParent = nextLayoutObject->parent();
  55     } else if (ContainerNode* containerNode = LayoutTreeBuilderTraversal::parent(element)) {
  56         m_layoutObjectParent = containerNode->layoutObject();
  57     }
  58 }
  59
  60 LayoutObject* LayoutTreeBuilderForElement::nextLayoutObject() const
  61 {
  62     ASSERT(m_layoutObjectParent);
  63
  64     if (m_node->isInTopLayer())
  65         return LayoutTreeBuilderTraversal::nextInTopLayer(*m_node);
  66
  67     if (m_node->isFirstLetterPseudoElement())
  68         return FirstLetterPseudoElement::firstLetterTextLayoutObject(*m_node);
  69
  70     return LayoutTreeBuilder::nextLayoutObject();
  71 }
  72
  73 LayoutObject* LayoutTreeBuilderForElement::parentLayoutObject() const
  74 {
  75     if (m_layoutObjectParent) {
  76         // FIXME: Guarding this by parentLayoutObject isn't quite right as the spec for
  77         // top layer only talks about display: none ancestors so putting a <dialog> inside an
  78         // <optgroup> seems like it should still work even though this check will prevent it.
  79         if (m_node->isInTopLayer())
  80             return m_node->document().layoutView();
  81     }
  82
  83     return m_layoutObjectParent;
  84 }
  85
  86 bool LayoutTreeBuilderForElement::shouldCreateLayoutObject() const
  87 {
  88     if (!m_layoutObjectParent)
  89         return false;
  90
  91     // FIXME: Should the following be in SVGElement::layoutObjectIsNeeded()?
  92     if (m_node->isSVGElement()) {
  93         // SVG elements only render when inside <svg>, or if the element is an <svg> itself.
  94         if (!isSVGSVGElement(*m_node) && (!m_layoutObjectParent->node() || !m_layoutObjectParent->node()->isSVGElement()))
  95             return false;
  96         if (!toSVGElement(m_node)->isValid())
  97             return false;
  98     }
  99
 100     LayoutObject* parentLayoutObject = this->parentLayoutObject();
 101     if (!parentLayoutObject)
 102         return false;
 103     if (!parentLayoutObject->canHaveChildren())
 104         return false;
 105
 106     return m_node->layoutObjectIsNeeded(style());
 107 }
 108
 109 ComputedStyle& LayoutTreeBuilderForElement::style() const
 110 {
 111     if (!m_style)
 112         m_style = m_node->styleForLayoutObject();
 113     return *m_style;
 114 }
 115
 116 void LayoutTreeBuilderForElement::createLayoutObject()
 117 {
 118     ComputedStyle& style = this->style();
 119
 120     LayoutObject* newLayoutObject = m_node->createLayoutObject(style);
 121     if (!newLayoutObject)
 122         return;
 123
 124     LayoutObject* parentLayoutObject = this->parentLayoutObject();
 125
 126     if (!parentLayoutObject->isChildAllowed(newLayoutObject, style)) {
 127         newLayoutObject->destroy();
 128         return;
 129     }
 130
 131     // Make sure the LayoutObject already knows it is going to be added to a LayoutFlowThread before we set the style
 132     // for the first time. Otherwise code using inLayoutFlowThread() in the styleWillChange and styleDidChange will fail.
 133     newLayoutObject->setIsInsideFlowThread(parentLayoutObject->isInsideFlowThread());
 134
 135     LayoutObject* nextLayoutObject = this->nextLayoutObject();
 136     m_node->setLayoutObject(newLayoutObject);
 137     newLayoutObject->setStyle(&style); // setStyle() can depend on layoutObject() already being set.
 138
 139     if (Fullscreen::isActiveFullScreenElement(*m_node)) {
 140         newLayoutObject = LayoutFullScreen::wrapLayoutObject(newLayoutObject, parentLayoutObject, &m_node->document());
 141         if (!newLayoutObject)
 142             return;
 143     }
 144
 145     // Note: Adding newLayoutObject instead of layoutObject(). layoutObject() may be a child of newLayoutObject.
 146     parentLayoutObject->addChild(newLayoutObject, nextLayoutObject);
 147 }
 148
 149 void LayoutTreeBuilderForText::createLayoutObject()
 150 {
 151     ComputedStyle& style = m_layoutObjectParent->mutableStyleRef();
 152
 153     ASSERT(m_node->textLayoutObjectIsNeeded(style, *m_layoutObjectParent));
 154
 155     LayoutText* newLayoutObject = m_node->createTextLayoutObject(style);
 156     if (!m_layoutObjectParent->isChildAllowed(newLayoutObject, style)) {
 157         newLayoutObject->destroy();
 158         return;
 159     }
 160
 161     // Make sure the LayoutObject already knows it is going to be added to a LayoutFlowThread before we set the style
 162     // for the first time. Otherwise code using inLayoutFlowThread() in the styleWillChange and styleDidChange will fail.
 163     newLayoutObject->setIsInsideFlowThread(m_layoutObjectParent->isInsideFlowThread());
 164
 165     LayoutObject* nextLayoutObject = this->nextLayoutObject();
 166     m_node->setLayoutObject(newLayoutObject);
 167     // Parent takes care of the animations, no need to call setAnimatableStyle.
 168     newLayoutObject->setStyle(&style);
 169     m_layoutObjectParent->addChild(newLayoutObject, nextLayoutObject);
 170 }
 171
 172 }