/*
 * Copyright 2005 Frerich Raabe <raabe@kde.org>
 * Copyright (C) 2006 Apple Computer, Inc.
 *
 * 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.
 */

#ifndef XPathValue_h
#define XPathValue_h

#include "core/CoreExport.h"
#include "core/xml/XPathNodeSet.h"
#include "wtf/text/WTFString.h"

namespace blink {

namespace XPath {

struct EvaluationContext;

class ValueData : public GarbageCollectedFinalized<ValueData> {
 public:
  static ValueData* create() { return new ValueData; }
  static ValueData* create(const NodeSet& nodeSet) {
    return new ValueData(nodeSet);
  }
  static ValueData* create(NodeSet* nodeSet) { return new ValueData(nodeSet); }
  static ValueData* create(const String& string) {
    return new ValueData(string);
  }
  DECLARE_TRACE();
  NodeSet& nodeSet() { return *m_nodeSet; }

  String m_string;

 private:
  ValueData() : m_nodeSet(NodeSet::create()) {}
  explicit ValueData(const NodeSet& nodeSet)
      : m_nodeSet(NodeSet::create(nodeSet)) {}
  explicit ValueData(NodeSet* nodeSet) : m_nodeSet(nodeSet) {}
  explicit ValueData(const String& string)
      : m_string(string), m_nodeSet(NodeSet::create()) {}

  Member<NodeSet> m_nodeSet;
};

// Copying Value objects makes their data partially shared, so care has to be
// taken when dealing with copies.
class CORE_EXPORT Value {
  DISALLOW_NEW();

 public:
  enum Type { NodeSetValue, BooleanValue, NumberValue, StringValue };

  Value(unsigned value) : m_type(NumberValue), m_bool(false), m_number(value) {}
  Value(unsigned long value)
      : m_type(NumberValue), m_bool(false), m_number(value) {}
  Value(double value) : m_type(NumberValue), m_bool(false), m_number(value) {}

  Value(const char* value)
      : m_type(StringValue),
        m_bool(false),
        m_number(0),
        m_data(ValueData::create(value)) {}
  Value(const String& value)
      : m_type(StringValue),
        m_bool(false),
        m_number(0),
        m_data(ValueData::create(value)) {}
  Value(const NodeSet& value)
      : m_type(NodeSetValue),
        m_bool(false),
        m_number(0),
        m_data(ValueData::create(value)) {}
  Value(Node* value)
      : m_type(NodeSetValue),
        m_bool(false),
        m_number(0),
        m_data(ValueData::create()) {
    m_data->nodeSet().append(value);
  }
  DECLARE_TRACE();

  // This is needed to safely implement constructing from bool - with normal
  // function overloading, any pointer type would match.
  template <typename T>
  Value(T);

  static const struct AdoptTag {
  } adopt;
  Value(NodeSet* value, const AdoptTag&)
      : m_type(NodeSetValue),
        m_bool(false),
        m_number(0),
        m_data(ValueData::create(value)) {}

  Type getType() const { return m_type; }

  bool isNodeSet() const { return m_type == NodeSetValue; }
  bool isBoolean() const { return m_type == BooleanValue; }
  bool isNumber() const { return m_type == NumberValue; }
  bool isString() const { return m_type == StringValue; }

  // If this is called during XPathExpression::evaluate(), EvaluationContext
  // should be passed.
  const NodeSet& toNodeSet(EvaluationContext*) const;
  NodeSet& modifiableNodeSet(EvaluationContext&);
  bool toBoolean() const;
  double toNumber() const;
  String toString() const;

 private:
  Type m_type;
  bool m_bool;
  double m_number;
  Member<ValueData> m_data;
};

template <>
inline Value::Value(bool value)
    : m_type(BooleanValue), m_bool(value), m_number(0) {}

}  // namespace XPath

}  // namespace blink

#endif  // XPathValue_h
