text: /*
   * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
   * Copyright (C) 2006, 2009, 2013 Apple 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
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #pragma once
  
  #include "XPathValue.h"
  
  namespace WebCore {
  namespace XPath {
  
  struct EvaluationContext {
      RefPtr<Node> node;
      unsigned size;
      unsigned position;
      HashMap<String, String> variableBindings;
  
      bool hadTypeConversionError;
  };
  
  class Expression {
      WTF_MAKE_NONCOPYABLE(Expression); WTF_MAKE_FAST_ALLOCATED;
  public:
      static EvaluationContext& evaluationContext();
  
      virtual ~Expression() = default;
  
      virtual Value evaluate() const = 0;
      virtual Value::Type resultType() const = 0;
  
      bool isContextNodeSensitive() const { return m_isContextNodeSensitive; }
      bool isContextPositionSensitive() const { return m_isContextPositionSensitive; }
      bool isContextSizeSensitive() const { return m_isContextSizeSensitive; }
  
  protected:
      Expression();
  
      unsigned subexpressionCount() const { return m_subexpressions.size(); }
      const Expression& subexpression(unsigned i) const { return *m_subexpressions[i]; }
  
      void addSubexpression(std::unique_ptr<Expression> expression)
      {
          m_isContextNodeSensitive |= expression->m_isContextNodeSensitive;
          m_isContextPositionSensitive |= expression->m_isContextPositionSensitive;
          m_isContextSizeSensitive |= expression->m_isContextSizeSensitive;
          m_subexpressions.append(WTFMove(expression));
      }
  
      void setSubexpressions(Vector<std::unique_ptr<Expression>>);
  
      void setIsContextNodeSensitive(bool value) { m_isContextNodeSensitive = value; }
      void setIsContextPositionSensitive(bool value) { m_isContextPositionSensitive = value; }
      void setIsContextSizeSensitive(bool value) { m_isContextSizeSensitive = value; }
  
  private:
      Vector<std::unique_ptr<Expression>> m_subexpressions;
  
      // Evaluation details that can be used for optimization.
      bool m_isContextNodeSensitive;
      bool m_isContextPositionSensitive;
      bool m_isContextSizeSensitive;
  };
  
  } // namespace XPath
  } // namespace WebCore
  