2016-03-02T18:53:01 LayoutPosition

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

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/editing/LayoutTreeTraversal.h"
+
+#include "core/layout/LayoutObject.h"
+
+namespace blink {
+
+LayoutObject* LayoutTreeTraversal::firstChild(const LayoutObject& layoutObject)
+{
+    return layoutObject.slowFirstChild();
+}
+
+bool LayoutTreeTraversal::hasChildren(const LayoutObject& layoutObject)
+{
+    return firstChild(layoutObject);
+}
+
+LayoutObject* LayoutTreeTraversal::lastChild(const LayoutObject& layoutObject)
+{
+    return layoutObject.slowLastChild();
+}
+
+LayoutObject* LayoutTreeTraversal::nextSibling(const LayoutObject& layoutObject)
+{
+    return layoutObject.nextSibling();
+}
+
+LayoutObject* LayoutTreeTraversal::parent(const LayoutObject& layoutObject)
+{
+    return layoutObject.parent();
+}
+
+LayoutObject* LayoutTreeTraversal::previousSibling(const LayoutObject& layoutObject)
+{
+    return layoutObject.previousSibling();
+}
+
+LayoutObject* LayoutTreeTraversal::next(const LayoutObject& layoutObject)
+{
+    if (LayoutObject* firstChild = LayoutTreeTraversal::firstChild(layoutObject))
+        return firstChild;
+    for (LayoutObject* runner = const_cast<LayoutObject*>(&layoutObject); runner; runner = LayoutTreeTraversal::parent(*runner)) {
+        if (LayoutObject* nextSibling = LayoutTreeTraversal::nextSibling(*runner))
+            return nextSibling;
+    }
+    return nullptr;
+}
+
+LayoutObject* LayoutTreeTraversal::previous(const LayoutObject& layoutObject)
+{
+    if (LayoutObject* previousSibling = LayoutTreeTraversal::previousSibling(layoutObject)) {
+        LayoutObject* result = previousSibling;
+        while (LayoutObject* lastChild = LayoutTreeTraversal::lastChild(*result))
+            result = lastChild;
+        return result;
+    }
+    return LayoutTreeTraversal::parent(layoutObject);
+}
+
+} // namespace blink