Introduce VisiblePosition::isValid

third_party/WebKit/Source/core/editing/VisiblePosition.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Portions Copyright (c) 2011 Motorola Mobility, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 27 matching lines @@
 #include "platform/geometry/FloatQuad.h"
 #include "wtf/text/CString.h"
 #include <ostream> // NOLINT
 
 namespace blink {
 
 using namespace HTMLNames;
 
 template <typename Strategy>
 VisiblePositionTemplate<Strategy>::VisiblePositionTemplate()
+#if DCHECK_IS_ON()
+    : m_domTreeVersion(0)
+    , m_styleVersion(0)
+#endif
 {
 }
 
 template <typename Strategy>
 VisiblePositionTemplate<Strategy>::VisiblePositionTemplate(const PositionWithAffinityTemplate<Strategy>& positionWithAffinity)
     : m_positionWithAffinity(positionWithAffinity)
+#if DCHECK_IS_ON()
+    , m_domTreeVersion(positionWithAffinity.position().document()->domTreeVersion())
+    , m_styleVersion(positionWithAffinity.position().document()->styleVersion())
+#endif
 {
 }
 
 template<typename Strategy>
 VisiblePositionTemplate<Strategy> VisiblePositionTemplate<Strategy>::create(const PositionWithAffinityTemplate<Strategy>& positionWithAffinity)
 {
     if (positionWithAffinity.isNull())
         return VisiblePositionTemplate<Strategy>();
     DCHECK(positionWithAffinity.position().isConnected()) << positionWithAffinity;
 
@@ skipping 143 matching lines @@
 #ifndef NDEBUG
 
 template<typename Strategy>
 void VisiblePositionTemplate<Strategy>::showTreeForThis() const
 {
     deepEquivalent().showTreeForThis();
 }
 
 #endif
 
+template <typename Strategy>
+bool VisiblePositionTemplate<Strategy>::isValid() const
+{
+#if DCHECK_IS_ON()
+    if (isNull())
+        return true;
+    Document& document = *m_positionWithAffinity.position().document();
+    return m_domTreeVersion == document.domTreeVersion() && m_styleVersion == document.styleVersion() && !document.needsLayoutTreeUpdate();
+#else
+    return true;
+#endif
+}
+
 template class CORE_TEMPLATE_EXPORT VisiblePositionTemplate<EditingStrategy>;
 template class CORE_TEMPLATE_EXPORT VisiblePositionTemplate<EditingInFlatTreeStrategy>;
 
 std::ostream& operator<<(std::ostream& ostream, const VisiblePosition& position)
 {
     return ostream << position.deepEquivalent() << '/' << position.affinity();
 }
 
 std::ostream& operator<<(std::ostream& ostream, const VisiblePositionInFlatTree& position)
 {
@@ skipping 12 matching lines @@
     }
     DVLOG(0) << "Cannot showTree for (nil) VisiblePosition.";
 }
 
 void showTree(const blink::VisiblePosition& vpos)
 {
     vpos.showTreeForThis();
 }
 
 #endif