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<?php
/*
** Zabbix
** Copyright (C) 2001-2019 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 class for implementing conversions used by the trigger wizard.
*/
class CTextTriggerConstructor {
const EXPRESSION_TYPE_MATCH = 0;
const EXPRESSION_TYPE_NO_MATCH = 1;
/**
* Parser used for parsing trigger expressions.
*
* @var CTriggerExpression
*/
protected $triggerExpression;
/**
* @param CTriggerExpression $triggerExpression trigger expression parser
*/
public function __construct(CTriggerExpression $triggerExpression) {
$this->triggerExpression = $triggerExpression;
}
/**
* Create a trigger expression from the given expression parts.
*
* Most of this function was left unchanged to preserve the current behavior of the constructor.
* Feel free to rewrite and correct it if necessary.
*
* @param string $host host name
* @param string $itemKey item key
* @param array $expressions array of expression parts
* @param string $expressions[]['value'] expression string
* @param int $expressions[]['type'] whether the string should match the expression; supported values:
* self::EXPRESSION_TYPE_MATCH and self::EXPRESSION_TYPE_NO_MATCH
*
* @return bool|string
*/
public function getExpressionFromParts($host, $itemKey, array $expressions) {
$result = '';
$prefix = $host.':'.$itemKey.'.';
if (empty($expressions)) {
error(_('Expression cannot be empty'));
return false;
}
// regexp used to split an expressions into tokens
$ZBX_PREG_EXPESSION_FUNC_FORMAT = '^(['.ZBX_PREG_PRINT.']*) (and|or) (not )?(-)? ?[(]*(([a-zA-Z_.\$]{6,7})(\\((['.ZBX_PREG_PRINT.']+?){0,1}\\)))(['.ZBX_PREG_PRINT.']*)$';
$functions = ['regexp' => 1, 'iregexp' => 1];
$expr_array = [];
$cexpor = 0;
$startpos = -1;
foreach ($expressions as $expression) {
if ($expression['type'] == self::EXPRESSION_TYPE_MATCH) {
if (!empty($result)) {
$result.=' or ';
}
if ($cexpor == 0) {
$startpos = mb_strlen($result);
}
$cexpor++;
$eq_global = '<>0';
}
else {
if (($cexpor > 1) & ($startpos >= 0)) {
$head = mb_substr($result, 0, $startpos);
$tail = mb_substr($result, $startpos);
$result = $head.'('.$tail.')';
}
$cexpor = 0;
$eq_global = '=0';
if (!empty($result)) {
$result.=' and ';
}
}
$expr = ' and '.$expression['value'];
// strip extra spaces around "and" and "or" operators
$expr = preg_replace('/\s+(and|or)\s+/U', ' $1 ', $expr);
$expr_array = [];
$sub_expr_count=0;
$sub_expr = '';
$multi = preg_match('/.+(and|or).+/', $expr);
// split an expression into separate tokens
// start from the first part of the expression, then move to the next one
while (preg_match('/'.$ZBX_PREG_EXPESSION_FUNC_FORMAT.'/i', $expr, $arr)) {
$arr[6] = strtolower($arr[6]);
if (!isset($functions[$arr[6]])) {
error(_('Incorrect function is used').'. ['.$expression['value'].']');
return false;
}
$expr_array[$sub_expr_count]['eq'] = trim($arr[2]);
$expr_array[$sub_expr_count]['not'] = trim($arr[3]);
$expr_array[$sub_expr_count]['minus'] = trim($arr[4]);
$expr_array[$sub_expr_count]['regexp'] = $arr[6].$arr[7];
$sub_expr_count++;
$expr = $arr[1];
}
if (empty($expr_array)) {
error(_('Incorrect trigger expression').'. ['.$expression['value'].']');
return false;
}
$expr_array[$sub_expr_count-1]['eq'] = '';
$sub_eq = '';
if ($multi > 0) {
$sub_eq = $eq_global;
}
foreach ($expr_array as $id => $expr) {
$eq = ($expr['eq'] === '') ? '' : ' '.$expr['eq'].' ';
$not = ($expr['not'] === '') ? '' : $expr['not'].' ';
if ($multi > 0) {
$sub_expr = $eq.'('.$not.$expr['minus'].'{'.$prefix.$expr['regexp'].'})'.$sub_eq.$sub_expr;
}
else {
$sub_expr = $eq.$expr['eq'].$not.$expr['minus'].'{'.$prefix.$expr['regexp'].'}'.$sub_eq.$sub_expr;
}
}
if ($multi > 0) {
$result .= '('.$sub_expr.')';
}
else {
$result .= '(('.$sub_expr.')'.$eq_global.')';
}
}
if (($cexpor > 1) & ($startpos >= 0)) {
$head = mb_substr($result, 0, $startpos);
$tail = mb_substr($result, $startpos);
$result = $head.'('.$tail.')';
}
return $result;
}
/**
* Break a trigger expression generated by the constructor.
*
* To be successfully parsed, each item function macro must be wrapped in additional parentheses, for example,
* (({item.item.regex(param)})=0)
*
* Most of this function was left unchanged to preserve the current behavior of the constructor.
* Feel free to rewrite and correct it if necessary.
*
* @param string $expression trigger expression
*
* @return array an array of expression parts, see self::getExpressionFromParts() for the structure of the part
* array
*/
public function getPartsFromExpression($expression) {
// strip extra parentheses
$expression = preg_replace('/\(\(\((.+?)\)\) and/i', '(($1) and', $expression);
$expression = preg_replace('/\(\(\((.+?)\)\)$/i', '(($1)', $expression);
$parseResult = $this->triggerExpression->parse($expression);
$expressions = [];
$splitTokens = $this->splitTokensByFirstLevel($parseResult->getTokens());
foreach($splitTokens as $key => $tokens) {
$expr = [];
// replace whole function macros with their functions
foreach ($tokens as $token) {
$value = $token['value'];
switch ($token['type']) {
case CTriggerExpressionParserResult::TOKEN_TYPE_FUNCTION_MACRO:
$value = $token['data']['function'];
break;
case CTriggerExpressionParserResult::TOKEN_TYPE_OPERATOR:
if ($token['value'] === 'and' || $token['value'] === 'or' || $token['value'] === 'not') {
$value = ' '.$token['value'].' ';
}
break;
}
$expr[] = $value;
}
$expr = implode($expr);
// trim surrounding parentheses
$expr = preg_replace('/^\((.*)\)$/u', '$1', $expr);
// trim parentheses around item function macros
$value = preg_replace('/\((.*)\)(=|<>)0/U', '$1', $expr);
// trim surrounding parentheses
$value = preg_replace('/^\((.*)\)$/u', '$1', $value);
$expressions[$key]['value'] = trim($value);
$expressions[$key]['type'] = (strpos($expr, '<>0', mb_strlen($expr) - 4) === false)
? self::EXPRESSION_TYPE_NO_MATCH
: self::EXPRESSION_TYPE_MATCH;
}
return $expressions;
}
/**
* Split the trigger expression tokens into separate arrays.
*
* The tokens are split at the first occurrence of the "and" or "or" operators with respect to parentheses.
*
* @param array $tokens an array of tokens from the CTriggerExpressionParserResult
*
* @return array an array of token arrays grouped by expression
*/
protected function splitTokensByFirstLevel(array $tokens) {
$expresions = [];
$currentExpression = [];
$level = 0;
foreach ($tokens as $token) {
switch ($token['type']) {
case CTriggerExpressionParserResult::TOKEN_TYPE_OPERATOR:
// look for an "or" or "and" operator on the top parentheses level
// if such an expression is found, save all of the tokens before it as a separate expression
if ($level == 0 && ($token['value'] === 'or' || $token['value'] === 'and')) {
$expresions[] = $currentExpression;
$currentExpression = [];
// continue to the next token
continue 2;
}
break;
case CTriggerExpressionParserResult::TOKEN_TYPE_OPEN_BRACE:
$level++;
break;
case CTriggerExpressionParserResult::TOKEN_TYPE_CLOSE_BRACE:
$level--;
break;
}
$currentExpression[] = $token;
}
$expresions[] = $currentExpression;
return $expresions;
}
}
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