TaQLNode.h

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// # TaQLNode.h: Envelope class for a node in the raw TaQL parse tree
// # Copyright (C) 2005
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 of the License, or (at your
// # option) any later version.
// #
// # This library is distributed in the hope that it will be useful, but WITHOUT
// # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef TABLES_TAQLNODE_H
#define TABLES_TAQLNODE_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/tables/TaQL/TaQLNodeRep.h>
#include <casacore/tables/TaQL/TaQLStyle.h>
 
#include <iostream>
#include <mutex>
#include <vector>
#include <memory>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declaration.
class AipsIO;
class TaQLNodeVisitor;
class TaQLMultiNode;
class TaQLConstNodeRep;
class TaQLRegexNodeRep;
class TaQLMultiNodeRep;
class TaQLQueryNodeRep;
 
// <summary>
// Envelope class for a node in the raw TaQL parse tree.
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="" date="" tests="tTaQLNode">
// </reviewed>
 
// <prerequisite>
// # Classes you should understand before using this one.
//   <li> <linkto group=TableGram.h#TableGramFunctions>TableGram</linkto>
//   <li> Note 199 describing
//        <a href="../notes/199.html">
//        TaQL</a>
// </prerequisite>
 
// <synopsis>
// The result of parsing a TaQL command is stored in TaQLNode objects.
// Each part of the command can have its own specialized
// <linkto class=TaQLNodeRep>TaQLNodeRep</linkto> object, which forms
// the letter in the TaQLNode envelope.
// <br>The actual scanning/parsing of the command is done using flex/bison
// as defined in the TableGram files.
// </synopsis>
 
// <motivation>
// The letter-envelope idiom (counted pointer) makes if much easier
// to keep track of memory, especially in the case of exceptions.
// </motivation>
 
class TaQLNode {
 public:
  // Default constructor.
  TaQLNode() {}
 
  // Construct for given letter. It takes over the pointer.
  TaQLNode(TaQLNodeRep* rep) { itsRep.reset(rep); }
 
  // Copy constructor (reference semantics).
  TaQLNode(const TaQLNode& that) { itsRep = that.itsRep; }
 
  // Assignment (reference semantics).
  TaQLNode& operator=(const TaQLNode& that) {
    if (this != &that) {
      itsRep = that.itsRep;
    }
    return *this;
  }
 
  // Get the TaQL style.
  const TaQLStyle& style() const { return itsRep->style(); }
 
  virtual ~TaQLNode() noexcept = default;
 
  // Parse a TaQL command and return the result.
  // An exception is thrown in case of parse errors.
  // The parse tree is deleted by function clearNodeCreated.
  static TaQLNode parse(const String& command);
 
  // Does the envelope contain a letter?
  Bool isValid() const { return Bool(itsRep); }
 
  // Return the type of letter.
  char nodeType() const { return itsRep->nodeType(); }
 
  // Get read access to the letter.
  const TaQLNodeRep* getRep() const { return itsRep.get(); }
 
  // Let the visitor visit the node.
  // If no node, return an empty result.
  TaQLNodeResult visit(TaQLNodeVisitor& visitor) const {
    return (itsRep ? itsRep->visit(visitor) : TaQLNodeResult());
  }
 
  // Print the node (recursively) in the given stream.
  void show(std::ostream& os) const {
    if (itsRep) itsRep->show(os);
  }
 
  // Save and restore the entire parse tree.
  // <group>
  void save(AipsIO& aio) const;
  static TaQLNode restore(AipsIO& aio);
  // </group>
 
 protected:
  std::shared_ptr<TaQLNodeRep> itsRep;
 
 private:
  // Delete all nodes that were created by the parser.
  static void clearNodesCreated();
 
 public:
  // Helper functions for save/restore of tree.
  // <group>
  void saveNode(AipsIO& aio) const;
  static TaQLNode restoreNode(AipsIO& aio);
  static TaQLMultiNode restoreMultiNode(AipsIO& aio);
  // </group>
 
  // The object getting the final tree.
  static TaQLNode theirNode;
  // A list of objects created by the parser and deleted at the end.
  static std::vector<TaQLNode*> theirNodesCreated;
  // Keep the TaQL style to use.
  static TaQLStyle theirStyle;
  // Use a mutex to guard the statics.
  static std::mutex theirMutex;
};
 
// <summary>
// Envelope class for a node containing a constant value.
// </summary>
// <use visibility=local>
// <reviewed reviewer="" date="" tests="tTaQLNode">
// </reviewed>
// <synopsis>
// This is a specialization of the envelope class
// <linkto class=TaQLNode>TaQLNode</linkto> for a node containing
// a constant value.
// </synopsis>
class TaQLConstNode : public TaQLNode {
 public:
  explicit TaQLConstNode(TaQLConstNodeRep* rep);
  void setIsTableName();
  const String& getString() const;
 
 private:
  TaQLConstNodeRep* itsNRep;
};
 
// <summary>
// Envelope class for a node containing a constant regex value.
// </summary>
// <use visibility=local>
// <reviewed reviewer="" date="" tests="tTaQLNode">
// </reviewed>
// <synopsis>
// This is a specialization of the envelope class
// <linkto class=TaQLNode>TaQLNode</linkto> for a node containing
// a constant regex or pattern value.
// </synopsis>
class TaQLRegexNode : public TaQLNode {
 public:
  explicit TaQLRegexNode(TaQLRegexNodeRep* rep);
  const String& getString() const;
  Bool caseInsensitive() const;
  Bool negate() const;
 
 private:
  TaQLRegexNodeRep* itsNRep;
};
 
// <summary>
// Envelope class for a node containing a list of nodes.
// </summary>
// <use visibility=local>
// <reviewed reviewer="" date="" tests="tTaQLNode">
// </reviewed>
// <synopsis>
// This is a specialization of the envelope class
// <linkto class=TaQLNode>TaQLNode</linkto> for a node containing
// a list of nodes.
// </synopsis>
class TaQLMultiNode : public TaQLNode {
 public:
  TaQLMultiNode();
  explicit TaQLMultiNode(Bool isSetOrArray);
  TaQLMultiNode(TaQLMultiNodeRep* rep);
  void add(const TaQLNode& node);
  void add(TaQLNodeRep* noderep);
  void setIsSetOrArray();
  void setPPFix(const String& prefix, const String& postfix);
  void setSeparator(const String& sep);
  void setSeparator(uInt incr, const String& sep);
  const TaQLMultiNodeRep* getMultiRep() const { return itsNRep; }
 
 private:
  TaQLMultiNodeRep* itsNRep;
};
 
// <summary>
// Envelope class for a node containing a selection command.
// </summary>
// <use visibility=local>
// <reviewed reviewer="" date="" tests="tTaQLNode">
// </reviewed>
// <synopsis>
// This is a specialization of the envelope class
// <linkto class=TaQLNode>TaQLNode</linkto> for a node containing
// a selection command.
// </synopsis>
class TaQLQueryNode : public TaQLNode {
 public:
  TaQLQueryNode(TaQLQueryNodeRep* rep);
  void setBrackets();
  void setNoExecute();
  void setFromExecute();
 
 private:
  TaQLQueryNodeRep* itsNRep;
};
 
}  // namespace casacore
 
#endif