/atk4/lib/Logger.php

<?php // vim:ts=4:sw=4:et:fdm=marker
/*
 * Undocumented
 *
 * @link http://agiletoolkit.org/
*//*
==ATK4===================================================
   This file is part of Agile Toolkit 4
    http://agiletoolkit.org/

   (c) 2008-2013 Agile Toolkit Limited <info@agiletoolkit.org>
   Distributed under Affero General Public License v3 and
   commercial license.

   See LICENSE or LICENSE_COM for more information
 =====================================================ATK4=*/
class Logger extends AbstractController {
    /**
     * Logger class is implemented a more sophisticated and usable error handling.
     *
     * Normally all error messages are sent through the API class by using one of two
     * ways:
     *
     * 1. throwing exception, which is caught by Api class (unless you catch it yourself)
     * 2. calling $this->fatal() which would throw exception for you (useful when calling
     *  from PHP4 compatible components)
     *
     * additionally there are way to pass info and warnings by calling:
     *
     * $this->warning();
     * $this->info();
     * $this->debug();
     *
     * Debug information will reach logs only if debug mode is set.
     *
     * ==[ Controling debug info ]===================================================
     *
     * AModules3 support two ways to set debug mode. Global and Local.
     *
     * Global mode is set by setting $api->debug to true. Local mode is set by setting
     * particular object's $this->debug to true.
     *
     * In local mode only debug info generated by particular object will be sent
     * through
     *
     * This class does not manage debug modes, which is a task for Api and all other
     * objects.
     *
     * $config['debug']=true; // turns on global debug mode.
     *
     *
     * ==[ Severity ]================================================================
     *
     * AModules3 have 4 severity types: debug, info, warning and fatal.
     *
     * Expected exceptions might be reported as warnings and uncaught exceptions
     * are fatal. Forms have their own validation and errors on the form is
     * completely separate system.
     *
     * Sample fatal errors:
     *  - unable to execute query
     *  - method not found
     *  - mandatory data is not specified
     * fatal errors will automatically terminate application execution.
     *
     * Warnings messages:
     *  - duplicate child added to the object with same name
     *  - method is called without specifying important argument
     *
     * Sample info messages:
     *  - user tried to access restricted page
     *  - monthly log rotation routine finished successfuly
     *  - user information is automatically converted (from format used in previous version)
     *  Info messages are passed as strings without extended information.
     *
     * Debug messages
     *  - called some function which might contain errors or being debuged
     *  - user logged in or logged out
     *  - when debuging, even more messages might be sent as debug()
     *  WARNING: please keep debug information to the minimum. Debug information is
     *  accompanied with extended information. Debug information is always saved into
     *  logs or is available on the screen.
     *
     * AModules3 core tries not to produce any debug or info messages to keep files
     * clean. Even if it does, those calls might eventually be cleaned out.
     *
     *
     * ==[ Configuring logger ]======================================================
    * Logger uses 2 output destinations, and 3 ways to restrict output information.
        *
        * Output destination: stdout (webpage), logs
        * Restrict options: 'full', 'light', null
        *
        * stdout is different for ApiCLI and ApiWeb classes. Web output might contact
        * tags or even some AJAX elements. Logs and ApiCLI uses the same output
        * format.
        *
        * Web output for info, warning and debug messages relies on templates
        * but fatal messages are template independent.
        *
        * ==[ Output restriction ]======================================================
        * null: this option will surpress all output. When used with logs, you won't
        * even need an empty directory. Web output will be clean of any messages.
        *
        * If fatal error occurs, if 'null' is used with web output, you will see
        * message (public_error_message), instead of the actual error.
        *
        *
        * light: only message is outputed. Even if debug mode is on, backtraces and
        * additional information is stripped off. This method is best if you are using
        * application for intranet and know uses or if you are doing beta testing.
        * This output won't contain any sensitive information such as table names, field
        * names, actual data)
        *
        * when used with logs, each message takes one line.
        *
        * full: this will output all the information available including:
        *  error message
        *  line/file/function where error message occured (guessed)
        *  additional information (such as last_query and error_message from DBlite)
        *  complete backtrace.
        *
        * when used with logs, each message takes several lines.
        *
        * ==[ Activation ]==================================================================
        * To start using this class in your applicaion you should:
            *
                *  $api->add('Logger');
    *
        * If you do not activate Logger, output will be similar to:
        * web_output='full';
    * log_output=null;
    *
        * ==[ Extending ]====================================================================
        *
        * You can extend this class to add additional features. Please notify me if you think
        * something essential is missing out
        *
        * romans@adevel.com
        *
        * Debug functions were contributed my mvs@adevel.com
        */

        // AModules3 compatibility
        public $owner;
    public $api;

    // Configuration;
    public $web_output='full';      // $config['logger']['web_output']
    public $log_output=null;        // $config['logger']['log_output']

    public $public_error_message=null;
    // This message will be outputed to user in case of
    // fatal error. When running in production mode, you
    // shouldn't show any debug info to user, but log them
    // instead

    public $log_dir;                // Directory where logs are created. It should be
    // used solely by AModules3. If not set, then
    // /var/log/atk4/<realm> will be used.
    //
    // You can change in $config['logger']['log_dir']

    protected $log_error_file;        // File we are currently logging errors to
    protected $log_debug_file;        // File we are currently logging errors to
    protected $log_info_file;         // File we are currently logging errors to
    public $details=array();


    private $html_stdout=false;

    private $header_sent=0;

    private $debug_log='';          // Will be outputed at the end of the page
    private $debug_added=false;     // no debug messages added yet


    function init(){
        parent::init();
        $this->debug_log=session_id()?$this->recall('debug_log',''):'';
        if(session_id())$this->forget('debug_log');
        $this->debug_log.="[<font color=red>Debug log from ".date("d.m.Y H:m:s")." to ".$_SERVER['QUERY_STRING']."</font>] - debug started<br>\n";
        $this->debug_added=false;

        register_shutdown_function(array($this,'showDebugInfo'));


        $this->log_output=$this->api->getConfig('logger/log_output',null);
        $this->web_output=$this->api->getConfig('logger/web_output','full');

        if(!$this->web_output){
            $this->public_error_message=$this->api
                ->getConfig('debug_public_error_message',
                        'We are currently having some technical difficulties. '.
                        'Please retry later.');
        }
        
        $this->log_dir=$this->api->getConfig('logger/log_dir',
            "/var/log/atk4/".$this->api->name);

        if($this->log_output){
            $this->openLogFile('error');
            $this->openLogFile('debug');
            $this->openLogFile('info');
            if(rand(1,50)==1)$this->cleanupLogDirectory();
        }

        if($this->log_output=='full'||$this->web_output=='full'){
            // Full logging will require some preparations
            $this->gatherDetails();
        }

        if($this->api instanceof ApiWeb){
            $this->html_stdout=true;
        }


        $this->api->addHook('caught-exception',array($this,'caughtException'));
        $this->api->addHook('output-fatal',array($this,'outputFatal'));
        $this->api->addHook('output-warning',array($this,'outputWarning'));
        $this->api->addHook('output-info',array($this,'outputInfo'));
        $this->api->addHook('output-debug',array($this,'outputDebug'));

        $this->api->debug('Logger is initialized');
    }
    function showDebugInfo(){
        if(!$this->debug_added)return;
        if(@$this->api->not_html){
            // We may not output anything, because this will screw up. Save debug output to session
            if(session_id())$this->memorize('debug_log',$this->debug_log);
        }else{
            echo $this->debug_log;
        }
    }
    function gatherDetails(){
        // Get IP address
        if (isset($_SERVER['REMOTE_ADDR'])) {
            //FIXME: generates warning - array_shift wants variable
            //$this->details['IP Address']=(isset($_SERVER["HTTP_X_FORWARDED_FOR"]) ? array_shift(explode(',', $_SERVER["HTTP_X_FORWARDED_FOR"])) : $_SERVER["REMOTE_ADDR"]);
        }

        if (isset($_SERVER['QUERY_STRING'])) {
            $this->details['Query String']=$_SERVER['QUERY_STRING'];
        }
        if (isset($_SERVER['REDIRECT_SCRIPT_URI'])) {
            $this->details['Original Query']=$_SERVER['REDIRECT_SCRIPT_URI'];
        }
        if (isset($_SERVER['HTTP_REFERER'])) {
            $this->details['Referer']=$_SERVER['HTTP_REFERER'];
        }
        if (isset($_SERVER['HTTP_USER_AGENT'])) {
            $this->details['Version']=$_SERVER['HTTP_USER_AGENT'];
        }
        if (isset($_SERVER['SERVER_PORT'])) {
            $this->details['Port']=$_SERVER['SERVER_PORT'];
        }
    }

    function findFrame($function_name,$shift=0){
        $backtrace=debug_backtrace();
        while($bt=array_shift($backtrace)){
            if($bt['function']==$function_name){
                while($shift--)$bt=array_shift($backtrace);
                return $bt;
            }
        }
        return array();
    }
    public $recskip=array();
    function showRenderTree($e,$obj){
        if(in_array($obj->name,$this->recskip)){
            echo '..recursion('.$obj.')';
            return;
        };
        $this->recskip[]=$obj;
        if($e->owner==$obj || $e->owner->owner == $obj || $e->owner->owner->owner == $obj){
            echo '<font color="red">'.$obj->__toString()."</font>";
        }else echo $obj->__toString();
        if($obj->elements){
            echo '<ul>';
            foreach($obj->elements as $name=>$object){
                echo '<li>'.$name.': ';
                $this->showRenderTree($e,$object);
                echo '</li>';
            }
            echo '</ul>';
        }
    }
    function logCaughtException($e){
        if(!$this->log_output)return;
        if(method_exists($e,'getMyTrace'))$trace=$e->getMyTrace();
        else $trace=$e->getTrace();

        $frame=$e->my_backtrace[$e->shift];
        $this->logLine($this->txtLine(get_class($e).": ".$e->getMessage(),$frame),2,'error',$trace);
        if(method_exists($e,'getAdditionalMessage'))
            $this->logLine($e->getAdditionalMessage(),2,'error');

        if($e->more_info){
            $this->logLine("Additional information:\n".
            $this->print_r(
                $e->more_info,'','','* ',"\n",' '),2,'error');
        }
    }
    function caughtException($caller,$e){
        $this->logCaughtException($e);
        if(!$this->web_output){
            echo $this->public_error_message;
            exit;
        }
        if($_GET[$this->name.'_debug']=='rendertree'){
            echo '<h2>Object Tree</h2>';
            try{
                $this->showRenderTree($e,$this->api);
            }catch(Exception $e){
                echo '<h1>Exception while trying to render tree:</h1>';
                //unset($_GET[$htis->name.'_debug']);
                //$this->api->caughtException($e);
            }
        }

        echo "<h2>Application Error: ". htmlspecialchars($e->getMessage()) ."</h2>\n";
        echo '<p><font color=red>' . get_class($e) . ', code: '.$e->getCode().'</font></p>';
        if($e->more_info){
            echo '<p>Additional information:';
            echo $this->print_r($e->more_info,'<ul>','</ul>','<li>','</li>',' ');
            echo '</p>';
        }
        if($e->actions){
            echo '<p>Possible Actions: <ul>';
            foreach($e->actions as $key=>$val){
                echo '<li><a href="'.$this->api->url(null,$val).'">'.$key.'</a></li>';
            }
            echo '</ul></p>';
        }
        if(method_exists($e,'getMyFile'))echo '<p><font color=blue>' . $e->getMyFile() . ':' . $e->getMyLine() . '</font></p>';

        if(method_exists($e,'getMyTrace'))echo $this->backtrace(3,$e->getMyTrace());
        else echo $this->backtrace($e->shift,$e->getTrace());

        echo "<p>Note: To hide this information from your users, add \$config['logger']['web_output']=false to your config.php file. Refer to documentation on 'Logger' for alternative logging options</p>";

        exit;
    }
    function print_r($key,$gs,$ge,$ls,$le,$ind=' '){
        $o='';
        if(strlen($ind)>3)return;
        if(is_array($key)){
            $o=$gs;
            foreach($key as $a=>$b){
                $o.= $ind.$ls.$a.': '.$this->print_r($b,$gs,$ge,$ls,$le,$ind.' ').$le;
            }
            $o.=$ge;

        }else{
            $o.=$gs?htmlspecialchars($key):$key;
        }
        return $o;
    }
    function outputWarning($caller,$msg,$shift=0){
        // first, let's see if we should log this
        $frame=$this->findFrame('warning',$shift);
        if($this->log_output){
            $this->logLine($this->txtLine("warning: $msg",$frame),'warning','error');
        }
        if(!$this->web_output){
            return true;
        }else{
            echo $this->html_stdout?
                $this->htmlLine("$msg",$frame,'warning'):
                $this->txtLine("$msg",$frame,'warning');
            return true;
        }
    }
    function outputDebug($caller,$msg,$shift=0){
        // first, let's see if we should log this
        $frame=$this->findFrame('debug');
        if($this->log_output){
            $this->logLine($this->txtLine("info: $msg",$frame),'fatal','debug');
        }
        if(!$this->web_output){
            return true;
        }else{
            $this->debug_added=true;
            $this->debug_log.=$this->html_stdout?
                $this->htmlLine("$msg",$frame,'debug'):
                $this->txtLine("$msg",$frame,'debug');
            return true;
        }
    }
    function outputInfo($caller,$msg,$shift=0,$nohtml=false){
        if($this->log_output){
            $this->logLine($this->txtLine("info: $msg"),null,'info');
        }
        if($this->web_output && !$nohtml){
            echo $this->html_stdout?
                $this->htmlLine("$msg",null,'info'):
                $this->txtLine("$msg",null,'info');
        }
        return true;
    }
    function outputFatal($caller,$msg,$shift=0){
        // first, let's see if we should log this
        $frame=$this->findFrame('fatal');
        if($this->log_output){
            $this->logLine($this->txtLine("fatal: $msg",$frame),'fatal','error');
        }
        if(!$this->web_output){
            echo $this->public_error_message;
        }else{
            if($this->html_stdout){
                echo "<h2>Fatal error</h2>\n";
            }
            echo $this->html_stdout?
                $this->htmlLine("$msg",$frame,'fatal'):
                $this->txtLine("$msg",$frame,'fatal');

            if($this->html_stdout){
                echo $this->backtrace('fatal');
            }else{
                echo "Stack trace:\n";
                echo $this->txtBacktrace('fatal');
            }

        }
        exit;
    }
    function htmlLine($msg,$frame=array(),$prefix=null){
        if(!$frame){
            return "<font style='font-family: verdana;  font-size:10px'><font color=blue>warning: </font> <font color=red><b>$msg</b></font></font><br>";
        }else{
            $errfile=dirname($frame['file']).'/<b>'.basename($frame['file']).'</b>';
            return "<font style='font-family: verdana;  font-size:10px'><font color=blue>$errfile:".$frame['line']."</font> <font color=red>".($prefix?"$prefix: ":"")."<b>$msg</b></font></font><br>";
        }
    }
    function txtLine($msg,$frame=array(),$prefix=null){
        if(!$frame){
            return "$prefix: $msg\n";
        }else{
            return basename($frame['file'])." on line ".$frame['line'].', path: '.dirname($frame['file'])."\n\n".
                ($prefix?"$prefix: ":"")."$msg\n\n";
        }
    }
    function logLine($msg,$shiftfunc=null,$severity='info',$trace=null){
        $log_file='log_'.$severity.'_file';
        if(!isset($this->$log_file))$this->openLogFile($severity);
        if($this->log_output==='full' && $severity=='error'){
            if(!$this->header_sent++){
                fputs($this->$log_file,"\n\n".
                        "============================================================\n".
                        "$msg".
                        "------------------------------------------------------------\n".
                        "Date: ".date("d-M-Y H:i:s")."\n");
                foreach($this->details as $key=>$val){
                    fputs($this->$log_file,"$key: $val\n");
                }
                fputs($this->$log_file,
                        "------------------------------------------------------------\n".
                        " Stack trace\n".
                        $this->txtBacktrace($shiftfunc,$trace).
                        "\n"
                     );
            }else{
                fputs($this->$log_file,$msg);
            }
        }elseif($this->log_output){
            fputs($this->$log_file,"[".date("d-M-Y H:i:s")."] $msg");
        }else{
            return;
        }
        fflush($this->$log_file);
    }
    function logVar($var,$msg="",$shiftfunc=null,$severity='debug'){
        //creating an $msg from variable
        $msg.="(".gettype($var)."):";
        if(is_array($var)||is_object($var))$msg .= print_r($var, true);
        else$msg .= $var;
        $this->logLine($msg."\n", $shiftfunc,$severity);
    }
    function logException($e){
        // logs exception from the catch statement
        // contains code from Logger::caughtException(), as this code won't launch
        // if exception is caught
        $frame=$e->my_backtrace[$e->shift-1];
        $this->logLine($this->txtLine(get_class($e).": (".$e->getCode().") ".$e->getMessage(),$frame),2,'error');
        return $this;
    }
    function openLogFile($severity='error'){
        if(!is_dir($this->log_dir)){
            // Directory is not writable, let's first try to create it
            if(!mkdir($this->log_dir,0750)){
                throw new BaseException("Unable to create $this->log_dir for log output");
            }
        }

        $filename='am3_'.$severity.'_log';
        $full_filename=$this->log_dir.DIRECTORY_SEPARATOR.$filename;
        if(!is_writable($full_filename) && !is_writable($this->log_dir))throw new BaseException("Log file is not writable and seems I won't be able to create it: $full_filename");
        if(is_link($full_filename))throw new BaseException("Log file is a symlink. Are you trying to make me overwrite somethingn?");


        ini_set($severity.'_log',$full_filename);

        //$full_filename=tempnam($this->log_dir,$filename);
        $new_file = (file_exists($full_filename))?false:true;
        $log_file="log_$severity"."_file";
        $this->$log_file=fopen($full_filename,"a");
        if(!$this->$log_file)throw new IOException("Cannot open $severity log file");
        if ($new_file) chmod($full_filename,0777); //
    }
    function writeLogMessage(){
    }
    function backtrace($sh=null,$backtrace=null){
        $output = "<div >\n";
        // TODO: allow extending backtrace option, so that 
        $output .= "<b>Stack trace:</b><br /><table style='border: 1px solid black; padding: 3px; text-align: left; font-family: verdana; font-size: 10px' width=100% cellspacing=0 cellpadding=0 border=0>\n";
        $output .= "<tr><th align='right'>File</th><th>&nbsp;</th><th>Object Name</th><th>Stack Trace</th></tr>";
        if(!isset($backtrace)) $backtrace=debug_backtrace();

        $n=0;
        foreach($backtrace as $bt){
            $n++;
            $args = '';
            if(!isset($bt['args']))continue;
            foreach($bt['args'] as $a){
                if(!empty($args)){
                    $args .= ', ';
                }
                switch (gettype($a)) {
                    case 'integer':
                    case 'double':
                        $args .= $a;
                        break;
                    case 'string':
                        $a = htmlspecialchars(substr($a, 0, 128)).((strlen($a) > 128) ? '...' : '');
                        $args .= "\"$a\"";
                        break;
                    case 'array':
                        $args .= "Array(".count($a).")";
                        break;
                    case 'object':
                        $args .= "Object(".get_class($a).")";
                        break;
                    case 'resource':
                        $args .= "Resource(".strstr($a, '#').")";
                        break;
                    case 'boolean':
                        $args .= $a ? 'True' : 'False';
                        break;
                    case 'NULL':
                        $args .= 'Null';
                        break;
                    default:
                        $args .= 'Unknown';
                }
            }

            if(($sh==null && strpos($bt['file'],'/atk4/lib/')===false) || (!is_int($sh) && $bt['function']==$sh)){
                $sh=$n;
            }

            $output .= "<tr><td valign=top align=right><font color=".($sh==$n?'red':'blue').">".htmlspecialchars(dirname($bt['file']))."/".
                "<b>".htmlspecialchars(basename($bt['file']))."</b></font></td>";
            $output .= "<td valign=top nowrap><font color=".($sh==$n?'red':'blue').">:{$bt['line']}</font>&nbsp;</td>";
            $name=(!isset($bt['object']->name))?get_class($bt['object']):$bt['object']->name;
            if($bt['object'])$output .= "<td>".$name."</td>";else $output.="<td></td>";
            $output .= "<td valign=top><font color=".($sh==$n?'red':'green').">".get_class($bt['object'])."{$bt['type']}<b>{$bt['function']}</b>($args)</font></td></tr>\n";
        }
        $output .= "</table></div>\n";
        return $output;
    }
    function cleanupLogDirectory(){
        // we should try to take care of our own log file cleanup
    }
    function txtBacktrace($sh=null,$backtrace=null){
        if(!isset($backtrace)) $backtrace=debug_backtrace();
        $output='';
        $n=0;
        foreach($backtrace as $bt){
            $n++;
            $args = '';
            if(!isset($bt['args']))$bt['args']=array();
            foreach($bt['args'] as $a){
                if(!empty($args)){
                    $args .= ', ';
                }
                switch (gettype($a)) {
                    case 'integer':
                    case 'double':
                        $args .= $a;
                        break;
                    case 'string':
                        $a = (substr($a, 0, 128)).((strlen($a) > 128) ? '...' : '');
                        $args .= "\"$a\"";
                        break;
                    case 'array':
                        $args .= "Array(".count($a).")";
                        break;
                    case 'object':
                        $args .= "Object(".get_class($a).")";
                        break;
                    case 'resource':
                        $args .= "Resource(".strstr($a, '#').")";
                        break;
                    case 'boolean':
                        $args .= $a ? 'True' : 'False';
                        break;
                    case 'NULL':
                        $args .= 'Null';
                        break;
                    default:
                        $args .= 'Unknown';
                }
            }

            if($sh){
                if(is_int($sh)){
                    if($sh>0){
                        $sh--;
                        continue;
                    }
                }elseif($bt['function']!=$sh){
                    $sh=null;
                    continue;
                }
            }

            $output .= $bt['file'].":".$bt['line']." ";
            $output .= "{$bt['class']}{$bt['type']}{$bt['function']}($args)\n";
        }
        return $output;
    }

    /*
    // Debug functions
    var $filename;

    var $err_message;

    var $_current_ip;

    var $_prev_exec_time;
     */

    function Debug($filename) {
        if (is_null($filename))
            $filename = dirname(__FILE__).DIRECTORY_SEPARATOR.'debug.log';

        $this->filename = $filename;

        if (isset($_SERVER['REMOTE_ADDR'])) {
            $this->_current_ip = (isset($_SERVER["HTTP_X_FORWARDED_FOR"]) ? array_shift(explode(',', $_SERVER["HTTP_X_FORWARDED_FOR"])) : $_SERVER["REMOTE_ADDR"]);
        }
    }

    function _sec2time($sec) {
        $res = '';
        if ($sec<0) {
            $sec = -$sec;
            $res = '-'.$res;
        }

        if ($sec!=floor($sec)) {
            $msec = round(($sec - floor($sec))*1000);

            $msec = '.'.str_pad($msec,3,'0', STR_PAD_LEFT);
            $sec = floor($sec);
        }

        $hours = floor($sec/3600);
        $min = floor(($sec - $hours*3600)/60);
        $sec  = $sec - $hours*3600 - $min*60;

        if ($hours > 0)
            $res .= str_pad($hours,2,'0', STR_PAD_LEFT).':';

        if (($hours > 0) or ($min > 0))
            $res .= str_pad($min,2,'0', STR_PAD_LEFT).':';

        $res .= str_pad($sec,2,'0', STR_PAD_LEFT).$msec;

        return $res;
    }

    function _microtime_float() {
        list($usec, $sec) = explode(" ", microtime());
        return ((float)$usec + (float)$sec);
    }

    // print
    function p($message, $file = null, $line = null) {
        $res = true;

        $time_diff_str = '';
        if (!empty($this->_prev_exec_time)) {
            $time_diff = $this->_microtime_float() - $this->_prev_exec_time;
            if ($time_diff < 1) $time_diff_str =  $this->_sec2time($time_diff);
        }

        $details = ((empty($this->_current_ip))?'':$this->_current_ip.' - ').
            ((!empty($file))?basename($file).' (line '.$line.')':'');

        if (!empty($details)) $details = ' ***** '.$details.' *****';

        $message = '['.date('d-M-Y H:i:s') . '] '.$time_diff_str.$details.
            "\n\n". $message . "\n\n";

        $new_file = (file_exists($this->filename))?false:true;
        $fh = @fopen($this->filename,'a');

        if (($fh !== false) and (is_resource($fh))) {
            @flock($fh, LOCK_EX);

            if (!@fwrite($fh, $message)) {
                $this->err_message = "Cannot write to file ($this->filename)";
                error_log($this->err_message.' in '.__FILE__.' on line '.__LINE__,0);
                $res = false;
            }
            @flock($fh, LOCK_UN);
            @fclose($fh);

            if ($new_file) chmod($this->filename,0777);
        }
        else {
            $this->err_message = 'Cannot open file ('.$this->filename.')'.
                ' in '.__FILE__.' on line '.__LINE__.' for save message: '."\n".$message;
            error_log($this->err_message,0);
            $res = false;
        }

        $this->_prev_exec_time = $this->_microtime_float();

        return $res;
    }
}