log.php

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<?php
/**
 * $Header$
 * $Horde: horde/lib/Log.php,v 1.15 2000/06/29 23:39:45 jon Exp $
 *
 * @version $Revision: 3355 $
 * @package Log
 */

define('PEAR_LOG_EMERG',    0);     /** System is unusable */
define('PEAR_LOG_ALERT',    1);     /** Immediate action required */
define('PEAR_LOG_CRIT',     2);     /** Critical conditions */
define('PEAR_LOG_ERR',      3);     /** Error conditions */
define('PEAR_LOG_WARNING',  4);     /** Warning conditions */
define('PEAR_LOG_NOTICE',   5);     /** Normal but significant */
define('PEAR_LOG_INFO',     6);     /** Informational */
define('PEAR_LOG_DEBUG',    7);     /** Debug-level messages */

define('PEAR_LOG_ALL',      bindec('11111111'));  /** All messages */
define('PEAR_LOG_NONE',     bindec('00000000'));  /** No message */

/* Log types for PHP's native error_log() function. */
define('PEAR_LOG_TYPE_SYSTEM',  0); /** Use PHP's system logger */
define('PEAR_LOG_TYPE_MAIL',    1); /** Use PHP's mail() function */
define('PEAR_LOG_TYPE_DEBUG',   2); /** Use PHP's debugging connection */
define('PEAR_LOG_TYPE_FILE',    3); /** Append to a file */

/**
 * The Log:: class implements both an abstraction for various logging
 * mechanisms and the Subject end of a Subject-Observer pattern.
 *
 * @author  Chuck Hagenbuch <[e-mail]>
 * @author  Jon Parise <[e-mail]>
 * @since   Horde 1.3
 * @package Log
 */
class Log
{
    /**
     * Indicates whether or not the log can been opened / connected.
     *
     * @var boolean
     * @access private
     */
    var $_opened = false;

    /**
     * Instance-specific unique identification number.
     *
     * @var integer
     * @access private
     */
    var $_id = 0;

    /**
     * The label that uniquely identifies this set of log messages.
     *
     * @var string
     * @access private
     */
    var $_ident = '';

    /**
     * The default priority to use when logging an event.
     *
     * @var integer
     * @access private
     */
    var $_priority = PEAR_LOG_INFO;

    /**
     * The bitmask of allowed log levels.
     * @var integer
     * @access private
     */
    var $_mask = PEAR_LOG_ALL;

    /**
     * Holds all Log_observer objects that wish to be notified of new messages.
     *
     * @var array
     * @access private
     */
    var $_listeners = array();


    /**
     * Attempts to return a concrete Log instance of type $handler.
     *
     * @param string $handler   The type of concrete Log subclass to return.
     *                          Attempt to dynamically include the code for
     *                          this subclass. Currently, valid values are
     *                          'console', 'syslog', 'sql', 'file', and 'mcal'.
     *
     * @param string $name      The name of the actually log file, table, or
     *                          other specific store to use. Defaults to an
     *                          empty string, with which the subclass will
     *                          attempt to do something intelligent.
     *
     * @param string $ident     The identity reported to the log system.
     *
     * @param array  $conf      A hash containing any additional configuration
     *                          information that a subclass might need.
     *
     * @param int $level        Log messages up to and including this level.
     *
     * @return object Log       The newly created concrete Log instance, or an
     *                          false on an error.
     * @access public
     * @since Log 1.0
     */
    function &factory($handler, $name = '', $ident = '', $conf = array(),
                      $level = PEAR_LOG_DEBUG)
    {
        $handler = strtolower($handler);
        $class = 'Log_' . $handler;
        $classfile = 'Log/' . $handler . '.php';

        /*
         * Attempt to include our version of the named class, but don't treat
         * a failure as fatal.  The caller may have already included their own
         * version of the named class.
         */
        @include_once $classfile;

        /* If the class exists, return a new instance of it. */
        if (class_exists($class)) {
            return new $class($name, $ident, $conf, $level);
        }

        return false;
    }

    /**
     * Attempts to return a reference to a concrete Log instance of type
     * $handler, only creating a new instance if no log instance with the same
     * parameters currently exists.
     *
     * You should use this if there are multiple places you might create a
     * logger, you don't want to create multiple loggers, and you don't want to
     * check for the existance of one each time. The singleton pattern does all
     * the checking work for you.
     *
     * <b>You MUST call this method with the $var = &Log::singleton() syntax.
     * Without the ampersand (&) in front of the method name, you will not get
     * a reference, you will get a copy.</b>
     *
     * @param string $handler   The type of concrete Log subclass to return.
     *                          Attempt to dynamically include the code for
     *                          this subclass. Currently, valid values are
     *                          'console', 'syslog', 'sql', 'file', and 'mcal'.
     *
     * @param string $name      The name of the actually log file, table, or
     *                          other specific store to use.  Defaults to an
     *                          empty string, with which the subclass will
     *                          attempt to do something intelligent.
     *
     * @param string $ident     The identity reported to the log system.
     *
     * @param array $conf       A hash containing any additional configuration
     *                          information that a subclass might need.
     *
     * @param int $level        Log messages up to and including this level.
     *
     * @return object Log       The newly created concrete Log instance, or an
     *                          false on an error.
     * @access public
     * @since Log 1.0
     */
    function &singleton($handler, $name = '', $ident = '', $conf = array(),
                        $level = PEAR_LOG_DEBUG)
    {
        static $instances;
        if (!isset($instances)) $instances = array();

        $signature = serialize(array($handler, $name, $ident, $conf, $level));
        if (!isset($instances[$signature])) {
            $instances[$signature] = &Log::factory($handler, $name, $ident,
                                                   $conf, $level);
        }

        return $instances[$signature];
    }

    /**
     * Abstract implementation of the open() method.
     * @since Log 1.0
     */
    function open()
    {
        return false;
    }

    /**
     * Abstract implementation of the close() method.
     * @since Log 1.0
     */
    function close()
    {
        return false;
    }

    /**
     * Abstract implementation of the flush() method.
     * @since Log 1.8.2
     */
    function flush()
    {
        return false;
    }

    /**
     * Abstract implementation of the log() method.
     * @since Log 1.0
     */
    function log($message, $priority = null)
    {
        return false;
    }

    /**
     * A convenience function for logging a emergency event.  It will log a
     * message at the PEAR_LOG_EMERG log level.
     *
     * @param   mixed   $message    String or object containing the message
     *                              to log.
     *
     * @return  boolean True if the message was successfully logged.
     *
     * @access  public
     * @since   Log 1.7.0
     */
    function emerg($message)
    {
        return $this->log($message, PEAR_LOG_EMERG);
    }

    /**
     * A convenience function for logging an alert event.  It will log a
     * message at the PEAR_LOG_ALERT log level.
     *
     * @param   mixed   $message    String or object containing the message
     *                              to log.
     *
     * @return  boolean True if the message was successfully logged.
     *
     * @access  public
     * @since   Log 1.7.0
     */
    function alert($message)
    {
        return $this->log($message, PEAR_LOG_ALERT);
    }

    /**
     * A convenience function for logging a critical event.  It will log a
     * message at the PEAR_LOG_CRIT log level.
     *
     * @param   mixed   $message    String or object containing the message
     *                              to log.
     *
     * @return  boolean True if the message was successfully logged.
     *
     * @access  public
     * @since   Log 1.7.0
     */
    function crit($message)
    {
        return $this->log($message, PEAR_LOG_CRIT);
    }

    /**
     * A convenience function for logging a error event.  It will log a
     * message at the PEAR_LOG_ERR log level.
     *
     * @param   mixed   $message    String or object containing the message
     *                              to log.
     *
     * @return  boolean True if the message was successfully logged.
     *
     * @access  public
     * @since   Log 1.7.0
     */
    function err($message)
    {
        return $this->log($message, PEAR_LOG_ERR);
    }

    /**
     * A convenience function for logging a warning event.  It will log a
     * message at the PEAR_LOG_WARNING log level.
     *
     * @param   mixed   $message    String or object containing the message
     *                              to log.
     *
     * @return  boolean True if the message was successfully logged.
     *
     * @access  public
     * @since   Log 1.7.0
     */
    function warning($message)
    {
        return $this->log($message, PEAR_LOG_WARNING);
    }

    /**
     * A convenience function for logging a notice event.  It will log a
     * message at the PEAR_LOG_NOTICE log level.
     *
     * @param   mixed   $message    String or object containing the message
     *                              to log.
     *
     * @return  boolean True if the message was successfully logged.
     *
     * @access  public
     * @since   Log 1.7.0
     */
    function notice($message)