include/util/Parser.hpp

/*
   Copyright (c) 2003, 2021, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program 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 General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#ifndef CPCD_PARSER_HPP
#define CPCD_PARSER_HPP

#include "Vector.hpp"
#include "Properties.hpp"
#include "InputStream.hpp"

class ParserImpl;
template<class T> struct ParserRow;

//#define PARSER_DEBUG
#ifdef PARSER_DEBUG
#include "NdbOut.hpp"
#define DEBUG(x) \
  ndbout_c("%s:%d:%s", __FILE__, __LINE__, x);
#else
#define DEBUG(x)
#endif

/**
 * A generic parser
 */
template<class T>
class Parser {
public:
  /**
   * Status for parser
   */
  enum ParserStatus {
    Ok                     = 0,
    Eof                    = 1,
    NoLine                 = 2,
    EmptyLine              = 3,
    UnknownCommand         = 4,
    UnknownArgument        = 5,
    TypeMismatch           = 6,
    InvalidArgumentFormat  = 7,
    UnknownArgumentType    = 8,
    CommandWithoutFunction = 9,
    ArgumentGivenTwice     = 10,
    ExternalStop           = 11,
    MissingMandatoryArgument = 12
  };

  /**
   * Context for parse
   */
  class Context {
  public:
    Context() { m_mutex= NULL; }
    ParserStatus m_status;
    const ParserRow<T> * m_currentCmd;
    const ParserRow<T> * m_currentArg;
    char * m_currentToken;
    STATIC_CONST(MaxParseBytes = 512);
    char m_tokenBuffer[ MaxParseBytes ];
    NdbMutex *m_mutex;

    Vector<const ParserRow<T> *> m_aliasUsed;
  };

  /**
   * Initialize parser
   */
  Parser(const ParserRow<T> rows[], class InputStream & in);
  ~Parser();

  /**
   * Run parser
   */
  bool run(Context &, T &, volatile bool * stop = 0) const;

  /**
   * Parse only one entry and return Properties object representing
   * the message
   */
  const Properties *parse(Context &, T &);

private:
  ParserImpl * impl;
};

template<class T>
struct ParserRow {
public:
  enum Type { Cmd, Arg, CmdAlias, ArgAlias, End }; // Put new types before end
  enum ArgType { String, Int, Properties };
  enum ArgRequired { Mandatory, Optional };
  enum ArgMinMax { CheckMinMax, IgnoreMinMax };

  const char * name;
  const char * realName;
  Type type;
  ArgType argType;
  ArgRequired argRequired;
  ArgMinMax argMinMax;
  int minVal;
  int maxVal;
  void (T::* function)(typename Parser<T>::Context & ctx,
		       const class Properties& args);
  const char * description;
  void *user_value;
};

/**
 * The void* equivalent implementation
 */
class ParserImpl {
public:
  class Dummy {};
  typedef ParserRow<Dummy> DummyRow;
  typedef Parser<Dummy>::Context Context;


  ParserImpl(const DummyRow rows[], class InputStream & in);
  ~ParserImpl();

  bool run(Context *ctx, const class Properties **, volatile bool *) const ;

  static const DummyRow* matchCommand(Context*, const char*, const DummyRow*);
  static const DummyRow* matchArg(Context*, const char *, const DummyRow *);
  static bool parseArg(Context*, char*, const DummyRow*, Properties*);
  static bool checkMandatory(Context*, const Properties*);
private:
  const DummyRow * const m_rows;
  class InputStream & input;

  void check_parser_rows(const DummyRow* rows) const;
};

template<class T>
inline
Parser<T>::Parser(const ParserRow<T> rows[], class InputStream & in) {
  impl = new ParserImpl((ParserImpl::DummyRow *)rows, in);
}

template<class T>
inline
Parser<T>::~Parser(){
  delete impl;
}

template<class T>
inline
bool
Parser<T>::run(Context & ctx, T & t, volatile bool * stop) const {
  const Properties * p;
  DEBUG("Executing Parser<T>::run");
  if(impl->run((ParserImpl::Context*)&ctx, &p, stop)){
    const ParserRow<T> * cmd = ctx.m_currentCmd; // Cast to correct type
    if(cmd == 0){
      /**
       * Should happen if run returns true
       */
      abort();
    }

    for(unsigned i = 0; i<ctx.m_aliasUsed.size(); i++){
      const ParserRow<T> * alias = ctx.m_aliasUsed[i];
      if(alias->function != 0){
	/**
	 * Report alias usage with callback (if specified by user)
	 */
	DEBUG("Alias usage with callback");
	(t.* alias->function)(ctx, * p);
      }
    }

    if(cmd->function == 0){
      ctx.m_status = CommandWithoutFunction;
      DEBUG("CommandWithoutFunction");
      delete p;
      return false;
    }
    (t.* cmd->function)(ctx, * p); // Call the function
    delete p;
    return true;
  }
  DEBUG("");
  return false;
}

template<class T>
inline
const Properties *
Parser<T>::parse(Context &ctx, T &t) {
  const Properties * p;
  volatile bool stop = false;
  DEBUG("Executing Parser<T>::parse");

  if(impl->run((ParserImpl::Context*)&ctx, &p, &stop)){
    const ParserRow<T> * cmd = ctx.m_currentCmd; // Cast to correct type
    if(cmd == 0){
      /**
       * Should happen if run returns true
       */
      abort();
    }

    for(unsigned i = 0; i<ctx.m_aliasUsed.size(); i++){
      const ParserRow<T> * alias = ctx.m_aliasUsed[i];
      if(alias->function != 0){
	/**
	 * Report alias usage with callback (if specified by user)
	 */
	DEBUG("Alias usage with callback");
	(t.* alias->function)(ctx, * p);
      }
    }

    if(cmd->function == 0){
      DEBUG("CommandWithoutFunction");
      ctx.m_status = CommandWithoutFunction;
      return p;
    }
    return p;
  }
  DEBUG("");
  return NULL;
}

#endif