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<?php
/*
** Zabbix
** Copyright (C) 2001-2023 Zabbix SIA
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** 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 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.
**/
/**
* A parser for function macros like "{?<trigger expression>}".
*/
class CExpressionMacroParser extends CParser {
/**
* @var CExpressionParser
*/
private $expression_parser;
/**
* @var string
*/
private $error = '';
/**
* @var array
*/
private $tokens = [];
/**
* An options array.
*
* Supported options:
* 'usermacros' => false Enable user macros usage in expression.
* 'lldmacros' => false Enable low-level discovery macros usage in expression.
* 'host_macro' => false Allow {HOST.HOST} macro as host name part in the query.
* 'host_macro_n' => false Allow {HOST.HOST} and {HOST.HOST<1-9>} macros as host name part in the query.
* 'empty_host' => false Allow empty hostname in the query string.
*
* @var array
*/
private $options = [
'usermacros' => false,
'lldmacros' => false,
'host_macro' => false,
'host_macro_n' => false,
'empty_host' => false
];
/**
* Set up necessary parsers.
*
* @param array $options
*/
public function __construct(array $options = []) {
$this->options = $options + $this->options;
$this->expression_parser = new CExpressionParser([
'usermacros' => $this->options['usermacros'],
'lldmacros' => $this->options['lldmacros'],
'host_macro' => $this->options['host_macro'],
'host_macro_n' => $this->options['host_macro_n'],
'empty_host' => $this->options['empty_host']
]);
}
/**
* @param string $source
* @param int $pos
*
* @return int
*/
public function parse($source, $pos = 0) {
$this->length = 0;
$this->match = '';
$this->error = '';
$p = $pos;
if (substr($source, $p, 2) !== '{?') {
return CParser::PARSE_FAIL;
}
$p += 2;
switch ($this->expression_parser->parse($source, $p)) {
case CParser::PARSE_SUCCESS_CONT:
$this->error = $this->expression_parser->getError();
break;
case CParser::PARSE_FAIL:
$this->error = $this->expression_parser->getError();
return CParser::PARSE_FAIL;
}
$p += $this->expression_parser->getLength();
while (isset($source[$p]) && strpos(CExpressionParser::WHITESPACES, $source[$p]) !== false) {
$p++;
}
if (!isset($source[$p])) {
$this->error = _('unexpected end of expression macro');
}
if (!isset($source[$p]) || $source[$p] !== '}') {
return CParser::PARSE_FAIL;
}
$p++;
$this->length = $p - $pos;
$this->match = substr($source, $pos, $this->length);
$this->tokens = $this->expression_parser->getResult()->getTokens();
return (isset($source[$p]) ? CParser::PARSE_SUCCESS_CONT : CParser::PARSE_SUCCESS);
}
/**
* Returns the error message if the expression macro is invalid.
*
* @return string
*/
public function getError(): string {
return $this->error;
}
/**
* Returns the expression parser.
*
* @return CExpressionParser
*/
public function getExpressionParser(): CExpressionParser {
return $this->expression_parser;
}
}
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