wiki.techinc.nl/includes/ScopedPHPTimeout.php

58 lines
2.1 KiB
PHP

<?php
/**
* Class to expand PHP execution time for a function call.
* On construction, set_time_limit() is called and set to $seconds.
* When the object goes out of scope, the timer is restarted, with
* the original time limit minus the time the object existed.
*/
class ScopedPHPTimeout {
protected $startTime; // float; seconds
protected $oldTimeout; // integer; seconds
protected static $stackDepth = 0; // integer
protected static $totalCalls = 0; // integer
protected static $totalElapsed = 0; // float; seconds
/* Prevent callers in infinite loops from running forever */
const MAX_TOTAL_CALLS = 1000000;
const MAX_TOTAL_TIME = 300; // seconds
/**
* @param $seconds integer
*/
public function __construct( $seconds ) {
if ( ini_get( 'max_execution_time' ) > 0 ) { // CLI uses 0
if ( self::$totalCalls >= self::MAX_TOTAL_CALLS ) {
trigger_error( "Maximum invocations of " . __CLASS__ . " exceeded." );
} elseif ( self::$totalElapsed >= self::MAX_TOTAL_TIME ) {
trigger_error( "Time limit within invocations of " . __CLASS__ . " exceeded." );
} elseif ( self::$stackDepth > 0 ) { // recursion guard
trigger_error( "Resursive invocation of " . __CLASS__ . " attempted." );
} else {
$this->oldTimeout = ini_set( 'max_execution_time', $seconds );
$this->startTime = microtime( true );
++self::$stackDepth;
++self::$totalCalls; // proof against < 1us scopes
}
}
}
/**
* Restore the original timeout.
* This does not account for the timer value on __construct().
*/
public function __destruct() {
if ( $this->oldTimeout ) {
$elapsed = microtime( true ) - $this->startTime;
// Note: a limit of 0 is treated as "forever"
set_time_limit( max( 1, $this->oldTimeout - (int)$elapsed ) );
// If each scoped timeout is for less than one second, we end up
// restoring the original timeout without any decrease in value.
// Thus web scripts in an infinite loop can run forever unless we
// take some measures to prevent this. Track total time and calls.
self::$totalElapsed += $elapsed;
--self::$stackDepth;
}
}
}