/*
 * Copyright (c) 2001, DecisionSoft Limited All rights reserved.
 * Please see LICENSE.TXT for more information.
 */

#ifndef _DATAITEMIMPL_HPP
#define _DATAITEMIMPL_HPP

class Sequence;
class DynamicContext;
class Numeric;

#include <pathan/dataItem/DataItem.hpp>

/** class which is used as base for all the different data types */
class PATHAN_EXPORT DataItemImpl : public DataItem
{
public:
  DataItemImpl(XPath2MemoryManager* memMgr);
  virtual ~DataItemImpl();

  DataItem::whichType getType(void) const;
	
  ///returns the predicate list to be applied to each node we select
  const VectorOfDataItems& getPredicates(void) const;
  //these can create a step if there are none!!
  virtual void addPredicates(const VectorOfDataItems &steps);

  /** Returns true if this DataItem has no predicates, and is an instance of
      DataItemSequence or DataItemLiteral */
  virtual bool isConstant() const;
  /** Returns true if this DataItem has no predicates, and is an instance of
      DataItemSequence or DataItemLiteral. If the literal value of this DataItem
      is a single DateOrTimeType, then hasTimezone() on it must return true,
      otherwise this method will return false. */
  virtual bool isConstantAndHasTimezone(StaticContext* context) const;

  ///calls collapseTreeInternal and then checks predicates
  virtual Sequence collapseTree(DynamicContext* context, int flags=0) const;

  //collapase the compiled expression based on context
  virtual Sequence collapseTreeInternal(DynamicContext* context, int flags=0) const = 0;

  void checkPredicates(Sequence &s, DynamicContext *context) const;
  virtual Sequence checkPredicate(const Sequence &s, const DataItem *predicate, DynamicContext *context) const;
  bool checkPredicate(const DataItem* predicate, DynamicContext* context) const;
  const Numeric *getConstantNumericPredicate(const DataItem *predicate, StaticContext *context) const;

  /** Calls staticResolution on the DataItems, then if isConstant() is true for
      all of them, and constantFold is true, returns the result of the
      constantFold() method, otherwise returns the result of the resolvePredicates()
      method. */
  DataItem *resolveDataItems(VectorOfDataItems &dis, StaticContext *context, StaticResolutionContext *src, bool constantFold);
  /** Calls staticResolution on the DataItems, then if isConstantAndHasTimezone() is true for
      all of them, and constantFold is true, returns the result of the
      constantFold() method, otherwise returns the result of the resolvePredicates()
      method. */
  DataItem *resolveDataItemsForDateOrTime(VectorOfDataItems &dis, StaticContext *context, StaticResolutionContext *src, bool constantFold);
  /** Calls staticResolution on the DataItem, then if isConstant() is true for
      it, and constantFold is true, returns the result of the
      constantFold() method, otherwise returns the result of the resolvePredicates()
      method. */
  DataItem *resolveDataItem(DataItem *&di, StaticContext *context, StaticResolutionContext *src, bool constantFold);
  /** Calls staticResolution on the predicates of this DataItem, constant folding
      if possible */
  DataItem *resolvePredicates(StaticContext *context, StaticResolutionContext *src);
  virtual DataItemImpl *resolvePredicate(VectorOfDataItems::reverse_iterator it, VectorOfDataItems &newPreds, StaticContext *context, StaticResolutionContext *src);
  /** Performs constant folding on this DataItem, transfering any predicates to
      the returned DataItem */
  DataItem *constantFold(StaticContext *context, StaticResolutionContext *src) const;

protected:
  void setType(DataItem::whichType t);
  XPath2MemoryManager* getMemoryManager(void) const;

  VectorOfDataItems _predList;

private:
  whichType _type;
  XPath2MemoryManager* _memMgr;
};

#endif