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/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* (C) 1999 Antti Koivisto (koivisto@kde.org)
* (C) 2001 Dirk Mueller (mueller@kde.org)
* Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
* rights reserved.
* Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
* (http://www.torchmobile.com/)
* Copyright (C) 2011 Google Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_DOM_LAYOUT_TREE_BUILDER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_DOM_LAYOUT_TREE_BUILDER_H_
#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/dom/node.h"
#include "third_party/blink/renderer/core/dom/text.h"
#include "third_party/blink/renderer/core/layout/layout_inline.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
namespace blink {
class ComputedStyle;
// The LayoutTreeBuilder class uses the DOM tree and CSS style rules as input to
// form a LayoutObject Tree which is then used for layout computations in a
// later stage.
// To construct the LayoutObject tree, the LayoutTreeBuilder does the following:
// 1. Starting at the root of the DOM tree, traverse each visible node.
// Visibility is determined by
// LayoutTreeBuilderFor{Element,Text}::ShouldCreateLayoutObject() functions.
// 2. For each visible node, ensure that the style has been resolved (either by
// getting the ComputedStyle passed on to the LayoutTreeBuilder or by forcing
// style resolution). This is done in LayoutTreeBuilderForElement::Style().
// 3. Emit visible LayoutObjects with content and their computed styles.
// This is dealt with by the
// LayoutTreeBuilderFor{Element,Text}::CreateLayoutObject() functions.
template <typename NodeType>
class LayoutTreeBuilder {
STACK_ALLOCATED();
protected:
LayoutTreeBuilder(NodeType& node,
Node::AttachContext& context,
const ComputedStyle* style)
: node_(node), context_(context), style_(style) {
DCHECK(!node.GetLayoutObject());
DCHECK(node.GetDocument().InStyleRecalc());
DCHECK(node.InActiveDocument());
DCHECK(context.parent);
}
LayoutObject* NextLayoutObject() const {
if (!context_.next_sibling_valid) {
context_.next_sibling =
LayoutTreeBuilderTraversal::NextSiblingLayoutObject(*node_);
context_.next_sibling_valid = true;
}
LayoutObject* next = context_.next_sibling;
// If a text node is wrapped in an anonymous inline for display:contents
// (see CreateInlineWrapperForDisplayContents()), use the wrapper as the
// next layout object. Otherwise we would need to add code to various
// AddChild() implementations to walk up the tree to find the correct
// layout tree parent/siblings.
if (next && next->IsText() && next->Parent()->IsAnonymous() &&
next->Parent()->IsInline()) {
return next->Parent();
}
return next;
}
Member<NodeType> node_;
Node::AttachContext& context_;
const ComputedStyle* style_;
};
class LayoutTreeBuilderForElement : public LayoutTreeBuilder<Element> {
public:
LayoutTreeBuilderForElement(Element&,
Node::AttachContext&,
const ComputedStyle*,
LegacyLayout legacy);
void CreateLayoutObject();
private:
LayoutObject* ParentLayoutObject() const;
LayoutObject* NextLayoutObject() const;
LegacyLayout legacy_;
};
class LayoutTreeBuilderForText : public LayoutTreeBuilder<Text> {
public:
LayoutTreeBuilderForText(Text& text,
Node::AttachContext& context,
const ComputedStyle* style_from_parent)
: LayoutTreeBuilder(text, context, style_from_parent) {}
void CreateLayoutObject();
private:
LayoutObject* CreateInlineWrapperForDisplayContentsIfNeeded();
};
} // namespace blink
#endif
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