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<?php
/**
* Expansion of the PHP execution time limit feature for a function call.
*
* 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.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
/**
* Class to expand PHP execution time for a function call.
* Use this when performing changes that should not be interrupted.
*
* On construction, set_time_limit() is called and set to $seconds.
* If the client aborts the connection, PHP will continue to run.
* 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 $oldIgnoreAbort; // boolean
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->oldIgnoreAbort = ignore_user_abort( true );
$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;
ignore_user_abort( $this->oldIgnoreAbort );
}
}
}
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