src/third_party/WebKit/Source/core/css/resolver/StyleResolverParentScope.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef StyleResolverParentScope_h
   6 #define StyleResolverParentScope_h
   7
   8 #include "core/css/resolver/StyleResolver.h"
   9 #include "core/dom/Document.h"
  10 #include "core/dom/Element.h"
  11 #include "core/dom/shadow/ShadowRoot.h"
  12
  13 namespace blink {
  14
  15 // Maintains the parent element stack (and bloom filter) inside recalcStyle.
  16 class StyleResolverParentScope FINAL {
  17     STACK_ALLOCATED();
  18 public:
  19     explicit StyleResolverParentScope(Node& parent);
  20     ~StyleResolverParentScope();
  21
  22     static void ensureParentStackIsPushed();
  23
  24 private:
  25     void pushParentIfNeeded();
  26     Node& parent() const { return *m_parent; }
  27
  28     RawPtrWillBeMember<Node> m_parent;
  29     bool m_pushed;
  30     StyleResolverParentScope* m_previous;
  31     StyleResolver& m_resolver;
  32
  33     static StyleResolverParentScope* s_currentScope;
  34 };
  35
  36 inline StyleResolverParentScope::StyleResolverParentScope(Node& parent)
  37     : m_parent(parent)
  38     , m_pushed(false)
  39     , m_previous(s_currentScope)
  40     , m_resolver(*parent.document().styleResolver())
  41 {
  42     ASSERT(parent.document().inStyleRecalc());
  43     ASSERT(parent.isElementNode() || parent.isShadowRoot());
  44     s_currentScope = this;
  45     m_resolver.increaseStyleSharingDepth();
  46 }
  47
  48 inline StyleResolverParentScope::~StyleResolverParentScope()
  49 {
  50     s_currentScope = m_previous;
  51     m_resolver.decreaseStyleSharingDepth();
  52     if (!m_pushed)
  53         return;
  54     if (parent().isElementNode())
  55         m_resolver.popParentElement(toElement(parent()));
  56 }
  57
  58 inline void StyleResolverParentScope::ensureParentStackIsPushed()
  59 {
  60     if (s_currentScope)
  61         s_currentScope->pushParentIfNeeded();
  62 }
  63
  64 inline void StyleResolverParentScope::pushParentIfNeeded()
  65 {
  66     if (m_pushed)
  67         return;
  68     if (m_previous)
  69         m_previous->pushParentIfNeeded();
  70     if (parent().isElementNode())
  71         m_resolver.pushParentElement(toElement(parent()));
  72     m_pushed = true;
  73 }
  74
  75 } // namespace blink
  76
  77 #endif // StyleResolverParentScope_h