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<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
* A simple rules engine, that parses and executes the rules in advisory_rules.txt.
* Adjusted to phpMyAdmin.
*
* @package PhpMyAdmin
*/
if (! defined('PHPMYADMIN')) {
exit;
}
/**
* Advisor class
*
* @package PhpMyAdmin
*/
class Advisor
{
var $variables;
var $parseResult;
var $runResult;
/**
* Parses and executes advisor rules
*
* @return array with run and parse results
*/
public function run()
{
// HowTo: A simple Advisory system in 3 easy steps.
// Step 1: Get some variables to evaluate on
$this->variables = array_merge(
$GLOBALS['dbi']->fetchResult('SHOW GLOBAL STATUS', 0, 1),
$GLOBALS['dbi']->fetchResult('SHOW GLOBAL VARIABLES', 0, 1)
);
if (PMA_DRIZZLE) {
$this->variables = array_merge(
$this->variables,
$GLOBALS['dbi']->fetchResult(
"SELECT concat('Com_', variable_name), variable_value "
. "FROM data_dictionary.GLOBAL_STATEMENTS", 0, 1
)
);
}
// Add total memory to variables as well
include_once 'libraries/sysinfo.lib.php';
$sysinfo = PMA_getSysInfo();
$memory = $sysinfo->memory();
$this->variables['system_memory']
= isset($memory['MemTotal']) ? $memory['MemTotal'] : 0;
// Step 2: Read and parse the list of rules
$this->parseResult = $this->parseRulesFile();
// Step 3: Feed the variables to the rules and let them fire. Sets
// $runResult
$this->runRules();
return array(
'parse' => array('errors' => $this->parseResult['errors']),
'run' => $this->runResult
);
}
/**
* Stores current error in run results.
*
* @param string $description description of an error.
* @param Exception $exception exception raised
*
* @return void
*/
public function storeError($description, $exception)
{
$this->runResult['errors'][] = $description
. ' '
. sprintf(
__('PHP threw following error: %s'),
$exception->getMessage()
);
}
/**
* Executes advisor rules
*
* @return boolean
*/
public function runRules()
{
$this->runResult = array(
'fired' => array(),
'notfired' => array(),
'unchecked'=> array(),
'errors' => array()
);
foreach ($this->parseResult['rules'] as $rule) {
$this->variables['value'] = 0;
$precond = true;
if (isset($rule['precondition'])) {
try {
$precond = $this->ruleExprEvaluate($rule['precondition']);
} catch (Exception $e) {
$this->storeError(
sprintf(
__('Failed evaluating precondition for rule \'%s\'.'),
$rule['name']
),
$e
);
continue;
}
}
if (! $precond) {
$this->addRule('unchecked', $rule);
} else {
try {
$value = $this->ruleExprEvaluate($rule['formula']);
} catch(Exception $e) {
$this->storeError(
sprintf(
__('Failed calculating value for rule \'%s\'.'),
$rule['name']
),
$e
);
continue;
}
$this->variables['value'] = $value;
try {
if ($this->ruleExprEvaluate($rule['test'])) {
$this->addRule('fired', $rule);
} else {
$this->addRule('notfired', $rule);
}
} catch(Exception $e) {
$this->storeError(
sprintf(
__('Failed running test for rule \'%s\'.'),
$rule['name']
),
$e
);
}
}
}
return true;
}
/**
* Escapes percent string to be used in format string.
*
* @param string $str string to escape
*
* @return string
*/
public static function escapePercent($str)
{
return preg_replace('/%( |,|\.|$|\(|\)|<|>)/', '%%\1', $str);
}
/**
* Wrapper function for translating.
*
* @param string $str the string
* @param string $param the parameters
*
* @return string
*/
public function translate($str, $param = null)
{
$string = _gettext(Advisor::escapePercent($str));
if (! is_null($param)) {
$params = $this->ruleExprEvaluate('array(' . $param . ')');
} else {
$params = array();
}
return vsprintf($string, $params);
}
/**
* Splits justification to text and formula.
*
* @param array $rule the rule
*
* @return string[]
*/
public static function splitJustification($rule)
{
$jst = preg_split('/\s*\|\s*/', $rule['justification'], 2);
if (count($jst) > 1) {
return array($jst[0], $jst[1]);
}
return array($rule['justification']);
}
/**
* Adds a rule to the result list
*
* @param string $type type of rule
* @param array $rule rule itself
*
* @return void
*/
public function addRule($type, $rule)
{
switch($type) {
case 'notfired':
case 'fired':
$jst = Advisor::splitJustification($rule);
if (count($jst) > 1) {
try {
/* Translate */
$str = $this->translate($jst[0], $jst[1]);
} catch (Exception $e) {
$this->storeError(
sprintf(
__('Failed formatting string for rule \'%s\'.'),
$rule['name']
),
$e
);
return;
}
$rule['justification'] = $str;
} else {
$rule['justification'] = $this->translate($rule['justification']);
}
$rule['id'] = $rule['name'];
$rule['name'] = $this->translate($rule['name']);
$rule['issue'] = $this->translate($rule['issue']);
// Replaces {server_variable} with 'server_variable'
// linking to server_variables.php
$rule['recommendation'] = preg_replace(
'/\{([a-z_0-9]+)\}/Ui',
'<a href="server_variables.php' . PMA_URL_getCommon()
. '&filter=\1">\1</a>',
$this->translate($rule['recommendation'])
);
// Replaces external Links with PMA_linkURL() generated links
$rule['recommendation'] = preg_replace_callback(
'#href=("|\')(https?://[^\1]+)\1#i',
array($this, '_replaceLinkURL'),
$rule['recommendation']
);
break;
}
$this->runResult[$type][] = $rule;
}
/**
* Callback for wrapping links with PMA_linkURL
*
* @param array $matches List of matched elements form preg_replace_callback
*
* @return string Replacement value
*/
private function _replaceLinkURL($matches)
{
return 'href="' . PMA_linkURL($matches[2]) . '" target="_blank"';
}
/**
* Callback for evaluating fired() condition.
*
* @param array $matches List of matched elements form preg_replace_callback
*
* @return string Replacement value
*/
private function _ruleExprEvaluateFired($matches)
{
// No list of fired rules
if (!isset($this->runResult['fired'])) {
return '0';
}
// Did matching rule fire?
foreach ($this->runResult['fired'] as $rule) {
if ($rule['id'] == $matches[2]) {
return '1';
}
}
return '0';
}
/**
* Callback for evaluating variables in expression.
*
* @param array $matches List of matched elements form preg_replace_callback
*
* @return string Replacement value
*/
private function _ruleExprEvaluateVariable($matches)
{
if (! isset($this->variables[$matches[1]])) {
return $matches[1];
}
if (is_numeric($this->variables[$matches[1]])) {
return $this->variables[$matches[1]];
} else {
return '\'' . addslashes($this->variables[$matches[1]]) . '\'';
}
}
/**
* Runs a code expression, replacing variable names with their respective
* values
*
* @param string $expr expression to evaluate
*
* @return integer result of evaluated expression
*
* @throws Exception
*/
public function ruleExprEvaluate($expr)
{
// Evaluate fired() conditions
$expr = preg_replace_callback(
'/fired\s*\(\s*(\'|")(.*)\1\s*\)/Ui',
array($this, '_ruleExprEvaluateFired'),
$expr
);
// Evaluate variables
$expr = preg_replace_callback(
'/\b(\w+)\b/',
array($this, '_ruleExprEvaluateVariable'),
$expr
);
$value = 0;
$err = 0;
// Actually evaluate the code
ob_start();
try {
eval('$value = ' . $expr . ';');
$err = ob_get_contents();
} catch (Exception $e) {
// In normal operation, there is just output in the buffer,
// but when running under phpunit, error in eval raises exception
$err = $e->getMessage();
}
ob_end_clean();
// Error handling
if ($err) {
throw new Exception(
strip_tags($err)
. '<br />Executed code: $value = ' . htmlspecialchars($expr) . ';'
);
}
return $value;
}
/**
* Reads the rule file into an array, throwing errors messages on syntax
* errors.
*
* @return array with parsed data
*/
public static function parseRulesFile()
{
$file = file('libraries/advisory_rules.txt', FILE_IGNORE_NEW_LINES);
$errors = array();
$rules = array();
$lines = array();
$ruleSyntax = array(
'name', 'formula', 'test', 'issue', 'recommendation', 'justification'
);
$numRules = count($ruleSyntax);
$numLines = count($file);
$ruleNo = -1;
$ruleLine = -1;
for ($i = 0; $i < $numLines; $i++) {
$line = $file[$i];
if ($line == "" || $line[0] == '#') {
continue;
}
// Reading new rule
if (substr($line, 0, 4) == 'rule') {
if ($ruleLine > 0) {
$errors[] = sprintf(
__(
'Invalid rule declaration on line %1$s, expected line '
. '%2$s of previous rule.'
),
$i + 1,
$ruleSyntax[$ruleLine++]
);
continue;
}
if (preg_match("/rule\s'(.*)'( \[(.*)\])?$/", $line, $match)) {
$ruleLine = 1;
$ruleNo++;
$rules[$ruleNo] = array('name' => $match[1]);
$lines[$ruleNo] = array('name' => $i + 1);
if (isset($match[3])) {
$rules[$ruleNo]['precondition'] = $match[3];
$lines[$ruleNo]['precondition'] = $i + 1;
}
} else {
$errors[] = sprintf(
__('Invalid rule declaration on line %s.'),
$i + 1
);
}
continue;
} else {
if ($ruleLine == -1) {
$errors[] = sprintf(
__('Unexpected characters on line %s.'),
$i + 1
);
}
}
// Reading rule lines
if ($ruleLine > 0) {
if (!isset($line[0])) {
continue; // Empty lines are ok
}
// Non tabbed lines are not
if ($line[0] != "\t") {
$errors[] = sprintf(
__(
'Unexpected character on line %1$s. Expected tab, but '
. 'found "%2$s".'
),
$i + 1,
$line[0]
);
continue;
}
$rules[$ruleNo][$ruleSyntax[$ruleLine]] = chop(
/*overload*/mb_substr($line, 1)
);
$lines[$ruleNo][$ruleSyntax[$ruleLine]] = $i + 1;
$ruleLine += 1;
}
// Rule complete
if ($ruleLine == $numRules) {
$ruleLine = -1;
}
}
return array('rules' => $rules, 'lines' => $lines, 'errors' => $errors);
}
}
/**
* Formats interval like 10 per hour
*
* @param integer $num number to format
* @param integer $precision required precision
*
* @return string formatted string
*/
function ADVISOR_bytime($num, $precision)
{
if ($num >= 1) { // per second
$per = __('per second');
} elseif ($num * 60 >= 1) { // per minute
$num = $num * 60;
$per = __('per minute');
} elseif ($num * 60 * 60 >= 1 ) { // per hour
$num = $num * 60 * 60;
$per = __('per hour');
} else {
$num = $num * 60 * 60 * 24;
$per = __('per day');
}
$num = round($num, $precision);
if ($num == 0) {
$num = '<' . PMA_Util::pow(10, -$precision);
}
return "$num $per";
}
/**
* Wrapper for PMA_Util::timespanFormat
*
* This function is used when evaluating advisory_rules.txt
*
* @param int $seconds the timespan
*
* @return string the formatted value
*/
function ADVISOR_timespanFormat($seconds)
{
return PMA_Util::timespanFormat($seconds);
}
/**
* Wrapper around PMA_Util::formatByteDown
*
* This function is used when evaluating advisory_rules.txt
*
* @param double $value the value to format
* @param int $limes the sensitiveness
* @param int $comma the number of decimals to retain
*
* @return string the formatted value with unit
*/
function ADVISOR_formatByteDown($value, $limes = 6, $comma = 0)
{
return implode(' ', PMA_Util::formatByteDown($value, $limes, $comma));
}
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