gnu-social/extlib/PEAR.php

<?php
/**
 * PEAR, the PHP Extension and Application Repository
 *
 * PEAR class and PEAR_Error class
 *
 * PHP versions 4 and 5
 *
 * @category   pear
 * @package    PEAR
 * @author     Sterling Hughes <sterling@php.net>
 * @author     Stig Bakken <ssb@php.net>
 * @author     Tomas V.V.Cox <cox@idecnet.com>
 * @author     Greg Beaver <cellog@php.net>
 * @copyright  1997-2010 The Authors
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @link       http://pear.php.net/package/PEAR
 * @since      File available since Release 0.1
 */

/**#@+
 * ERROR constants
 */
define('PEAR_ERROR_RETURN',     1);
define('PEAR_ERROR_PRINT',      2);
define('PEAR_ERROR_TRIGGER',    4);
define('PEAR_ERROR_DIE',        8);
define('PEAR_ERROR_CALLBACK',  16);
/**
 * WARNING: obsolete
 * @deprecated
 */
define('PEAR_ERROR_EXCEPTION', 32);
/**#@-*/

if (substr(PHP_OS, 0, 3) == 'WIN') {
    define('OS_WINDOWS', true);
    define('OS_UNIX',    false);
    define('PEAR_OS',    'Windows');
} else {
    define('OS_WINDOWS', false);
    define('OS_UNIX',    true);
    define('PEAR_OS',    'Unix'); // blatant assumption
}

$GLOBALS['_PEAR_default_error_mode']     = PEAR_ERROR_RETURN;
$GLOBALS['_PEAR_default_error_options']  = E_USER_NOTICE;
$GLOBALS['_PEAR_destructor_object_list'] = array();
$GLOBALS['_PEAR_shutdown_funcs']         = array();
$GLOBALS['_PEAR_error_handler_stack']    = array();

@ini_set('track_errors', true);

/**
 * Base class for other PEAR classes.  Provides rudimentary
 * emulation of destructors.
 *
 * If you want a destructor in your class, inherit PEAR and make a
 * destructor method called _yourclassname (same name as the
 * constructor, but with a "_" prefix).  Also, in your constructor you
 * have to call the PEAR constructor: $this->PEAR();.
 * The destructor method will be called without parameters.  Note that
 * at in some SAPI implementations (such as Apache), any output during
 * the request shutdown (in which destructors are called) seems to be
 * discarded.  If you need to get any debug information from your
 * destructor, use error_log(), syslog() or something similar.
 *
 * IMPORTANT! To use the emulated destructors you need to create the
 * objects by reference: $obj =& new PEAR_child;
 *
 * @category   pear
 * @package    PEAR
 * @author     Stig Bakken <ssb@php.net>
 * @author     Tomas V.V. Cox <cox@idecnet.com>
 * @author     Greg Beaver <cellog@php.net>
 * @copyright  1997-2006 The PHP Group
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @version    Release: @package_version@
 * @link       http://pear.php.net/package/PEAR
 * @see        PEAR_Error
 * @since      Class available since PHP 4.0.2
 * @link        http://pear.php.net/manual/en/core.pear.php#core.pear.pear
 */
class PEAR
{
    function getVersion(){} // This is an ugly patch for a crazy bug
    /**
     * Whether to enable internal debug messages.
     *
     * @var     bool
     * @access  private
     */
    var $_debug = false;

    /**
     * Default error mode for this object.
     *
     * @var     int
     * @access  private
     */
    var $_default_error_mode = null;

    /**
     * Default error options used for this object when error mode
     * is PEAR_ERROR_TRIGGER.
     *
     * @var     int
     * @access  private
     */
    var $_default_error_options = null;

    /**
     * Default error handler (callback) for this object, if error mode is
     * PEAR_ERROR_CALLBACK.
     *
     * @var     string
     * @access  private
     */
    var $_default_error_handler = '';

    /**
     * Which class to use for error objects.
     *
     * @var     string
     * @access  private
     */
    var $_error_class = 'PEAR_Error';

    /**
     * An array of expected errors.
     *
     * @var     array
     * @access  private
     */
    var $_expected_errors = array();

    /**
     * List of methods that can be called both statically and non-statically.
     * @var array
     */
    protected static $bivalentMethods = array(
        'setErrorHandling' => true,
        'raiseError' => true,
        'throwError' => true,
        'pushErrorHandling' => true,
        'popErrorHandling' => true,
    );

    /**
     * Constructor.  Registers this object in
     * $_PEAR_destructor_object_list for destructor emulation if a
     * destructor object exists.
     *
     * @param string $error_class  (optional) which class to use for
     *        error objects, defaults to PEAR_Error.
     * @access public
     * @return void
     */
    function __construct($error_class = null)
    {
        $classname = strtolower(get_class($this));
        if ($this->_debug) {
            print "PEAR constructor called, class=$classname\n";
        }

        if ($error_class !== null) {
            $this->_error_class = $error_class;
        }

        while ($classname && strcasecmp($classname, "pear")) {
            $destructor = "_$classname";
            if (method_exists($this, $destructor)) {
                global $_PEAR_destructor_object_list;
                $_PEAR_destructor_object_list[] = $this;
                if (!isset($GLOBALS['_PEAR_SHUTDOWN_REGISTERED'])) {
                    register_shutdown_function("_PEAR_call_destructors");
                    $GLOBALS['_PEAR_SHUTDOWN_REGISTERED'] = true;
                }
                break;
            } else {
                $classname = get_parent_class($classname);
            }
        }
    }

    /**
     * Only here for backwards compatibility.
     * E.g. Archive_Tar calls $this->PEAR() in its constructor.
     *
     * @param string $error_class Which class to use for error objects,
     *                            defaults to PEAR_Error.
     */
    public function PEAR($error_class = null)
    {
        self::__construct($error_class);
    }

    /**
     * Destructor (the emulated type of...).  Does nothing right now,
     * but is included for forward compatibility, so subclass
     * destructors should always call it.
     *
     * See the note in the class desciption about output from
     * destructors.
     *
     * @access public
     * @return void
     */
    function _PEAR() {
        if ($this->_debug) {
            printf("PEAR destructor called, class=%s\n", strtolower(get_class($this)));
        }
    }

    public function __call($method, $arguments)
    {
        if (!isset(self::$bivalentMethods[$method])) {
            trigger_error(
                'Call to undefined method PEAR::' . $method . '()', E_USER_ERROR
            );
        }
        return call_user_func_array(
            array(get_class(), '_' . $method),
            array_merge(array($this), $arguments)
        );
    }

    public static function __callStatic($method, $arguments)
    {
        if (!isset(self::$bivalentMethods[$method])) {
            trigger_error(
                'Call to undefined method PEAR::' . $method . '()', E_USER_ERROR
            );
        }
        return call_user_func_array(
            array(get_class(), '_' . $method),
            array_merge(array(null), $arguments)
        );
    }

    /**
    * If you have a class that's mostly/entirely static, and you need static
    * properties, you can use this method to simulate them. Eg. in your method(s)
    * do this: $myVar = &PEAR::getStaticProperty('myclass', 'myVar');
    * You MUST use a reference, or they will not persist!
    *
    * @param  string $class  The calling classname, to prevent clashes
    * @param  string $var    The variable to retrieve.
    * @return mixed   A reference to the variable. If not set it will be
    *                 auto initialised to NULL.
    */
    public static function &getStaticProperty($class, $var)
    {
        static $properties;
        if (!isset($properties[$class])) {
            $properties[$class] = array();
        }

        if (!array_key_exists($var, $properties[$class])) {
            $properties[$class][$var] = null;
        }

        return $properties[$class][$var];
    }

    /**
    * Use this function to register a shutdown method for static
    * classes.
    *
    * @param  mixed $func  The function name (or array of class/method) to call
    * @param  mixed $args  The arguments to pass to the function
    *
    * @return void
    */
    public static function registerShutdownFunc($func, $args = array())
    {
        // if we are called statically, there is a potential
        // that no shutdown func is registered.  Bug #6445
        if (!isset($GLOBALS['_PEAR_SHUTDOWN_REGISTERED'])) {
            register_shutdown_function("_PEAR_call_destructors");
            $GLOBALS['_PEAR_SHUTDOWN_REGISTERED'] = true;
        }
        $GLOBALS['_PEAR_shutdown_funcs'][] = array($func, $args);
    }

    /**
     * Tell whether a value is a PEAR error.
     *
     * @param   mixed $data   the value to test
     * @param   int   $code   if $data is an error object, return true
     *                        only if $code is a string and
     *                        $obj->getMessage() == $code or
     *                        $code is an integer and $obj->getCode() == $code
     *
     * @return  bool    true if parameter is an error
     */
    public static function isError($data, $code = null)
    {
        if (!is_a($data, 'PEAR_Error')) {
            return false;
        }

        if (is_null($code)) {
            return true;
        } elseif (is_string($code)) {
            return $data->getMessage() == $code;
        }

        return $data->getCode() == $code;
    }

    /**
     * Sets how errors generated by this object should be handled.
     * Can be invoked both in objects and statically.  If called
     * statically, setErrorHandling sets the default behaviour for all
     * PEAR objects.  If called in an object, setErrorHandling sets
     * the default behaviour for that object.
     *
     * @param object $object
     *        Object the method was called on (non-static mode)
     *
     * @param int $mode
     *        One of PEAR_ERROR_RETURN, PEAR_ERROR_PRINT,
     *        PEAR_ERROR_TRIGGER, PEAR_ERROR_DIE,
     *        PEAR_ERROR_CALLBACK or PEAR_ERROR_EXCEPTION.
     *
     * @param mixed $options
     *        When $mode is PEAR_ERROR_TRIGGER, this is the error level (one
     *        of E_USER_NOTICE, E_USER_WARNING or E_USER_ERROR).
     *
     *        When $mode is PEAR_ERROR_CALLBACK, this parameter is expected
     *        to be the callback function or method.  A callback
     *        function is a string with the name of the function, a
     *        callback method is an array of two elements: the element
     *        at index 0 is the object, and the element at index 1 is
     *        the name of the method to call in the object.
     *
     *        When $mode is PEAR_ERROR_PRINT or PEAR_ERROR_DIE, this is
     *        a printf format string used when printing the error
     *        message.
     *
     * @access public
     * @return void
     * @see PEAR_ERROR_RETURN
     * @see PEAR_ERROR_PRINT
     * @see PEAR_ERROR_TRIGGER
     * @see PEAR_ERROR_DIE
     * @see PEAR_ERROR_CALLBACK
     * @see PEAR_ERROR_EXCEPTION
     *
     * @since PHP 4.0.5
     */
    protected static function _setErrorHandling(
        $object, $mode = null, $options = null
    ) {
        if ($object !== null) {
            $setmode     = &$object->_default_error_mode;
            $setoptions  = &$object->_default_error_options;
        } else {
            $setmode     = &$GLOBALS['_PEAR_default_error_mode'];
            $setoptions  = &$GLOBALS['_PEAR_default_error_options'];
        }

        switch ($mode) {
            case PEAR_ERROR_EXCEPTION:
            case PEAR_ERROR_RETURN:
            case PEAR_ERROR_PRINT:
            case PEAR_ERROR_TRIGGER:
            case PEAR_ERROR_DIE:
            case null:
                $setmode = $mode;
                $setoptions = $options;
                break;

            case PEAR_ERROR_CALLBACK:
                $setmode = $mode;
                // class/object method callback
                if (is_callable($options)) {
                    $setoptions = $options;
                } else {
                    trigger_error("invalid error callback", E_USER_WARNING);
                }
                break;

            default:
                trigger_error("invalid error mode", E_USER_WARNING);
                break;
        }
    }

    /**
     * This method is used to tell which errors you expect to get.
     * Expected errors are always returned with error mode
     * PEAR_ERROR_RETURN.  Expected error codes are stored in a stack,
     * and this method pushes a new element onto it.  The list of
     * expected errors are in effect until they are popped off the
     * stack with the popExpect() method.
     *
     * Note that this method can not be called statically
     *
     * @param mixed $code a single error code or an array of error codes to expect
     *
     * @return int     the new depth of the "expected errors" stack
     * @access public
     */
    function expectError($code = '*')
    {
        if (is_array($code)) {
            array_push($this->_expected_errors, $code);
        } else {
            array_push($this->_expected_errors, array($code));
        }
        return count($this->_expected_errors);
    }

    /**
     * This method pops one element off the expected error codes
     * stack.
     *
     * @return array   the list of error codes that were popped
     */
    function popExpect()
    {
        return array_pop($this->_expected_errors);
    }

    /**
     * This method checks unsets an error code if available
     *
     * @param mixed error code
     * @return bool true if the error code was unset, false otherwise
     * @access private
     * @since PHP 4.3.0
     */
    function _checkDelExpect($error_code)
    {
        $deleted = false;
        foreach ($this->_expected_errors as $key => $error_array) {
            if (in_array($error_code, $error_array)) {
                unset($this->_expected_errors[$key][array_search($error_code, $error_array)]);
                $deleted = true;
            }

            // clean up empty arrays
            if (0 == count($this->_expected_errors[$key])) {
                unset($this->_expected_errors[$key]);
            }
        }

        return $deleted;
    }

    /**
     * This method deletes all occurrences of the specified element from
     * the expected error codes stack.
     *
     * @param  mixed $error_code error code that should be deleted
     * @return mixed list of error codes that were deleted or error
     * @access public
     * @since PHP 4.3.0
     */
    function delExpect($error_code)
    {
        $deleted = false;
        if ((is_array($error_code) && (0 != count($error_code)))) {
            // $error_code is a non-empty array here; we walk through it trying
            // to unset all values
            foreach ($error_code as $key => $error) {
                $deleted =  $this->_checkDelExpect($error) ? true : false;
            }

            return $deleted ? true : PEAR::raiseError("The expected error you submitted does not exist"); // IMPROVE ME
        } elseif (!empty($error_code)) {
            // $error_code comes alone, trying to unset it
            if ($this->_checkDelExpect($error_code)) {
                return true;
            }

            return PEAR::raiseError("The expected error you submitted does not exist"); // IMPROVE ME
        }

        // $error_code is empty
        return PEAR::raiseError("The expected error you submitted is empty"); // IMPROVE ME
    }

    /**
     * This method is a wrapper that returns an instance of the
     * configured error class with this object's default error
     * handling applied.  If the $mode and $options parameters are not
     * specified, the object's defaults are used.
     *
     * @param mixed $message a text error message or a PEAR error object
     *
     * @param int $code      a numeric error code (it is up to your class
     *                  to define these if you want to use codes)
     *
     * @param int $mode      One of PEAR_ERROR_RETURN, PEAR_ERROR_PRINT,
     *                  PEAR_ERROR_TRIGGER, PEAR_ERROR_DIE,
     *                  PEAR_ERROR_CALLBACK, PEAR_ERROR_EXCEPTION.
     *
     * @param mixed $options If $mode is PEAR_ERROR_TRIGGER, this parameter
     *                  specifies the PHP-internal error level (one of
     *                  E_USER_NOTICE, E_USER_WARNING or E_USER_ERROR).
     *                  If $mode is PEAR_ERROR_CALLBACK, this
     *                  parameter specifies the callback function or
     *                  method.  In other error modes this parameter
     *                  is ignored.
     *
     * @param string $userinfo If you need to pass along for example debug
     *                  information, this parameter is meant for that.
     *
     * @param string $error_class The returned error object will be
     *                  instantiated from this class, if specified.
     *
     * @param bool $skipmsg If true, raiseError will only pass error codes,
     *                  the error message parameter will be dropped.
     *
     * @return object   a PEAR error object
     * @see PEAR::setErrorHandling
     * @since PHP 4.0.5
     */
    protected static function _raiseError($object,
                         $message = null,
                         $code = null,
                         $mode = null,
                         $options = null,
                         $userinfo = null,
                         $error_class = null,
                         $skipmsg = false)
    {
        // The error is yet a PEAR error object
        if (is_object($message)) {
            $code        = $message->getCode();
            $userinfo    = $message->getUserInfo();
            $error_class = $message->getType();
            $message->error_message_prefix = '';
            $message     = $message->getMessage();
        }

        if (
            $object !== null &&
            isset($object->_expected_errors) &&
            count($object->_expected_errors) > 0 &&
            count($exp = end($object->_expected_errors))
        ) {
            if ($exp[0] === "*" ||
                (is_int(reset($exp)) && in_array($code, $exp)) ||
                (is_string(reset($exp)) && in_array($message, $exp))
            ) {
                $mode = PEAR_ERROR_RETURN;
            }
        }

        // No mode given, try global ones
        if ($mode === null) {
            // Class error handler
            if ($object !== null && isset($object->_default_error_mode)) {
                $mode    = $object->_default_error_mode;
                $options = $object->_default_error_options;
            // Global error handler
            } elseif (isset($GLOBALS['_PEAR_default_error_mode'])) {
                $mode    = $GLOBALS['_PEAR_default_error_mode'];
                $options = $GLOBALS['_PEAR_default_error_options'];
            }
        }

        if ($error_class !== null) {
            $ec = $error_class;
        } elseif ($object !== null && isset($object->_error_class)) {
            $ec = $object->_error_class;
        } else {
            $ec = 'PEAR_Error';
        }

        if ($skipmsg) {
            $a = new $ec($code, $mode, $options, $userinfo);
        } else {
            $a = new $ec($message, $code, $mode, $options, $userinfo);
        }

        return $a;
    }

    /**
     * Simpler form of raiseError with fewer options.  In most cases
     * message, code and userinfo are enough.
     *
     * @param mixed $message a text error message or a PEAR error object
     *
     * @param int $code      a numeric error code (it is up to your class
     *                  to define these if you want to use codes)
     *
     * @param string $userinfo If you need to pass along for example debug
     *                  information, this parameter is meant for that.
     *
     * @return object   a PEAR error object
     * @see PEAR::raiseError
     */
    protected static function _throwError($object, $message = null, $code = null, $userinfo = null)
    {
        if ($object !== null) {
            $a = $object->raiseError($message, $code, null, null, $userinfo);
            return $a;
        }

        $a = PEAR::raiseError($message, $code, null, null, $userinfo);
        return $a;
    }

    public static function staticPushErrorHandling($mode, $options = null)
    {
        $stack       = &$GLOBALS['_PEAR_error_handler_stack'];
        $def_mode    = &$GLOBALS['_PEAR_default_error_mode'];
        $def_options = &$GLOBALS['_PEAR_default_error_options'];
        $stack[] = array($def_mode, $def_options);
        switch ($mode) {
            case PEAR_ERROR_EXCEPTION:
            case PEAR_ERROR_RETURN:
            case PEAR_ERROR_PRINT:
            case PEAR_ERROR_TRIGGER:
            case PEAR_ERROR_DIE:
            case null:
                $def_mode = $mode;
                $def_options = $options;
                break;

            case PEAR_ERROR_CALLBACK:
                $def_mode = $mode;
                // class/object method callback
                if (is_callable($options)) {
                    $def_options = $options;
                } else {
                    trigger_error("invalid error callback", E_USER_WARNING);
                }
                break;

            default:
                trigger_error("invalid error mode", E_USER_WARNING);
                break;
        }
        $stack[] = array($mode, $options);
        return true;
    }

    public static function staticPopErrorHandling()
    {
        $stack = &$GLOBALS['_PEAR_error_handler_stack'];
        $setmode     = &$GLOBALS['_PEAR_default_error_mode'];
        $setoptions  = &$GLOBALS['_PEAR_default_error_options'];
        array_pop($stack);
        list($mode, $options) = $stack[sizeof($stack) - 1];
        array_pop($stack);
        switch ($mode) {
            case PEAR_ERROR_EXCEPTION:
            case PEAR_ERROR_RETURN:
            case PEAR_ERROR_PRINT:
            case PEAR_ERROR_TRIGGER:
            case PEAR_ERROR_DIE:
            case null:
                $setmode = $mode;
                $setoptions = $options;
                break;

            case PEAR_ERROR_CALLBACK:
                $setmode = $mode;
                // class/object method callback
                if (is_callable($options)) {
                    $setoptions = $options;
                } else {
                    trigger_error("invalid error callback", E_USER_WARNING);
                }
                break;

            default:
                trigger_error("invalid error mode", E_USER_WARNING);
                break;
        }
        return true;
    }

    /**
     * Push a new error handler on top of the error handler options stack. With this
     * you can easily override the actual error handler for some code and restore
     * it later with popErrorHandling.
     *
     * @param mixed $mode (same as setErrorHandling)
     * @param mixed $options (same as setErrorHandling)
     *
     * @return bool Always true
     *
     * @see PEAR::setErrorHandling
     */
    protected static function _pushErrorHandling($object, $mode, $options = null)
    {
        $stack = &$GLOBALS['_PEAR_error_handler_stack'];
        if ($object !== null) {
            $def_mode    = &$object->_default_error_mode;
            $def_options = &$object->_default_error_options;
        } else {
            $def_mode    = &$GLOBALS['_PEAR_default_error_mode'];
            $def_options = &$GLOBALS['_PEAR_default_error_options'];
        }
        $stack[] = array($def_mode, $def_options);

        if ($object !== null) {
            $object->setErrorHandling($mode, $options);
        } else {
            PEAR::setErrorHandling($mode, $options);
        }
        $stack[] = array($mode, $options);
        return true;
    }

    /**
    * Pop the last error handler used
    *
    * @return bool Always true
    *
    * @see PEAR::pushErrorHandling
    */
    protected static function _popErrorHandling($object)
    {
        $stack = &$GLOBALS['_PEAR_error_handler_stack'];
        array_pop($stack);
        list($mode, $options) = $stack[sizeof($stack) - 1];
        array_pop($stack);
        if ($object !== null) {
            $object->setErrorHandling($mode, $options);
        } else {
            PEAR::setErrorHandling($mode, $options);
        }
        return true;
    }

    /**
    * OS independent PHP extension load. Remember to take care
    * on the correct extension name for case sensitive OSes.
    *
    * @param string $ext The extension name
    * @return bool Success or not on the dl() call
    */
    public static function loadExtension($ext)
    {
        if (extension_loaded($ext)) {
            return true;
        }

        // if either returns true dl() will produce a FATAL error, stop that
        if (
            function_exists('dl') === false ||
            ini_get('enable_dl') != 1
        ) {
            return false;
        }

        if (OS_WINDOWS) {
            $suffix = '.dll';
        } elseif (PHP_OS == 'HP-UX') {
            $suffix = '.sl';
        } elseif (PHP_OS == 'AIX') {
            $suffix = '.a';
        } elseif (PHP_OS == 'OSX') {
            $suffix = '.bundle';
        } else {
            $suffix = '.so';
        }

        return @dl('php_'.$ext.$suffix) || @dl($ext.$suffix);
    }
}

function _PEAR_call_destructors()
{
    global $_PEAR_destructor_object_list;
    if (is_array($_PEAR_destructor_object_list) &&
        sizeof($_PEAR_destructor_object_list))
    {
        reset($_PEAR_destructor_object_list);

        $destructLifoExists = PEAR::getStaticProperty('PEAR', 'destructlifo');

        if ($destructLifoExists) {
            $_PEAR_destructor_object_list = array_reverse($_PEAR_destructor_object_list);
        }

        foreach ($_PEAR_destructor_object_list as $k => $objref) {
            $classname = get_class($objref);
            while ($classname) {
                $destructor = "_$classname";
                if (method_exists($objref, $destructor)) {
                    $objref->$destructor();
                    break;
                } else {
                    $classname = get_parent_class($classname);
                }
            }
        }
        // Empty the object list to ensure that destructors are
        // not called more than once.
        $_PEAR_destructor_object_list = array();
    }

    // Now call the shutdown functions
    if (
        isset($GLOBALS['_PEAR_shutdown_funcs']) &&
        is_array($GLOBALS['_PEAR_shutdown_funcs']) &&
        !empty($GLOBALS['_PEAR_shutdown_funcs'])
    ) {
        foreach ($GLOBALS['_PEAR_shutdown_funcs'] as $value) {
            call_user_func_array($value[0], $value[1]);
        }
    }
}

/**
 * Standard PEAR error class for PHP 4
 *
 * This class is supserseded by {@link PEAR_Exception} in PHP 5
 *
 * @category   pear
 * @package    PEAR
 * @author     Stig Bakken <ssb@php.net>
 * @author     Tomas V.V. Cox <cox@idecnet.com>
 * @author     Gregory Beaver <cellog@php.net>
 * @copyright  1997-2006 The PHP Group
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @version    Release: @package_version@
 * @link       http://pear.php.net/manual/en/core.pear.pear-error.php
 * @see        PEAR::raiseError(), PEAR::throwError()
 * @since      Class available since PHP 4.0.2
 */
class PEAR_Error
{
    var $error_message_prefix = '';
    var $mode                 = PEAR_ERROR_RETURN;
    var $level                = E_USER_NOTICE;
    var $code                 = -1;
    var $message              = '';
    var $userinfo             = '';
    var $backtrace            = null;

    /**
     * PEAR_Error constructor
     *
     * @param string $message  message
     *
     * @param int $code     (optional) error code
     *
     * @param int $mode     (optional) error mode, one of: PEAR_ERROR_RETURN,
     * PEAR_ERROR_PRINT, PEAR_ERROR_DIE, PEAR_ERROR_TRIGGER,
     * PEAR_ERROR_CALLBACK or PEAR_ERROR_EXCEPTION
     *
     * @param mixed $options   (optional) error level, _OR_ in the case of
     * PEAR_ERROR_CALLBACK, the callback function or object/method
     * tuple.
     *
     * @param string $userinfo (optional) additional user/debug info
     *
     * @access public
     *
     */
    function __construct($message = 'unknown error', $code = null,
                        $mode = null, $options = null, $userinfo = null)
    {
        if ($mode === null) {
            $mode = PEAR_ERROR_RETURN;
        }
        $this->message   = $message;
        $this->code      = $code;
        $this->mode      = $mode;
        $this->userinfo  = $userinfo;

        $skiptrace = PEAR::getStaticProperty('PEAR_Error', 'skiptrace');

        if (!$skiptrace) {
            $this->backtrace = debug_backtrace();
            if (isset($this->backtrace[0]) && isset($this->backtrace[0]['object'])) {
                unset($this->backtrace[0]['object']);
            }
        }

        if ($mode & PEAR_ERROR_CALLBACK) {
            $this->level = E_USER_NOTICE;
            $this->callback = $options;
        } else {
            if ($options === null) {
                $options = E_USER_NOTICE;
            }

            $this->level = $options;
            $this->callback = null;
        }

        if ($this->mode & PEAR_ERROR_PRINT) {
            if (is_null($options) || is_int($options)) {
                $format = "%s";
            } else {
                $format = $options;
            }

            printf($format, $this->getMessage());
        }

        if ($this->mode & PEAR_ERROR_TRIGGER) {
            trigger_error($this->getMessage(), $this->level);
        }

        if ($this->mode & PEAR_ERROR_DIE) {
            $msg = $this->getMessage();
            if (is_null($options) || is_int($options)) {
                $format = "%s";
                if (substr($msg, -1) != "\n") {
                    $msg .= "\n";
                }
            } else {
                $format = $options;
            }
            printf($format, $msg);
            exit($code);
        }

        if ($this->mode & PEAR_ERROR_CALLBACK && is_callable($this->callback)) {
            call_user_func($this->callback, $this);
        }

        if ($this->mode & PEAR_ERROR_EXCEPTION) {
            trigger_error("PEAR_ERROR_EXCEPTION is obsolete, use class PEAR_Exception for exceptions", E_USER_WARNING);
            eval('$e = new Exception($this->message, $this->code);throw($e);');
        }
    }

    /**
     * Only here for backwards compatibility.
     *
     * Class "Cache_Error" still uses it, among others.
     *
     * @param string $message  Message
     * @param int    $code     Error code
     * @param int    $mode     Error mode
     * @param mixed  $options  See __construct()
     * @param string $userinfo Additional user/debug info
     */
    public function PEAR_Error(
        $message = 'unknown error', $code = null, $mode = null,
        $options = null, $userinfo = null
    ) {
        self::__construct($message, $code, $mode, $options, $userinfo);
    }

    /**
     * Get the error mode from an error object.
     *
     * @return int error mode
     * @access public
     */
    function getMode()
    {
        return $this->mode;
    }

    /**
     * Get the callback function/method from an error object.
     *
     * @return mixed callback function or object/method array
     * @access public
     */
    function getCallback()
    {
        return $this->callback;
    }

    /**
     * Get the error message from an error object.
     *
     * @return  string  full error message
     * @access public
     */
    function getMessage()
    {
        return ($this->error_message_prefix . $this->message);
    }

    /**
     * Get error code from an error object
     *
     * @return int error code
     * @access public
     */
     function getCode()
     {
        return $this->code;
     }

    /**
     * Get the name of this error/exception.
     *
     * @return string error/exception name (type)
     * @access public
     */
    function getType()
    {
        return get_class($this);
    }

    /**
     * Get additional user-supplied information.
     *
     * @return string user-supplied information
     * @access public
     */
    function getUserInfo()
    {
        return $this->userinfo;
    }

    /**
     * Get additional debug information supplied by the application.
     *
     * @return string debug information
     * @access public
     */
    function getDebugInfo()
    {
        return $this->getUserInfo();
    }

    /**
     * Get the call backtrace from where the error was generated.
     * Supported with PHP 4.3.0 or newer.
     *
     * @param int $frame (optional) what frame to fetch
     * @return array Backtrace, or NULL if not available.
     * @access public
     */
    function getBacktrace($frame = null)
    {
        if (defined('PEAR_IGNORE_BACKTRACE')) {
            return null;
        }
        if ($frame === null) {
            return $this->backtrace;
        }
        return $this->backtrace[$frame];
    }

    function addUserInfo($info)
    {
        if (empty($this->userinfo)) {
            $this->userinfo = $info;
        } else {
            $this->userinfo .= " ** $info";
        }
    }

    function __toString()
    {
        return $this->getMessage();
    }

    /**
     * Make a string representation of this object.
     *
     * @return string a string with an object summary
     * @access public
     */
    function toString()
    {
        $modes = array();
        $levels = array(E_USER_NOTICE  => 'notice',
                        E_USER_WARNING => 'warning',
                        E_USER_ERROR   => 'error');
        if ($this->mode & PEAR_ERROR_CALLBACK) {
            if (is_array($this->callback)) {
                $callback = (is_object($this->callback[0]) ?
                    strtolower(get_class($this->callback[0])) :
                    $this->callback[0]) . '::' .
                    $this->callback[1];
            } else {
                $callback = $this->callback;
            }
            return sprintf('[%s: message="%s" code=%d mode=callback '.
                           'callback=%s prefix="%s" info="%s"]',
                           strtolower(get_class($this)), $this->message, $this->code,
                           $callback, $this->error_message_prefix,
                           $this->userinfo);
        }
        if ($this->mode & PEAR_ERROR_PRINT) {
            $modes[] = 'print';
        }
        if ($this->mode & PEAR_ERROR_TRIGGER) {
            $modes[] = 'trigger';
        }
        if ($this->mode & PEAR_ERROR_DIE) {
            $modes[] = 'die';
        }
        if ($this->mode & PEAR_ERROR_RETURN) {
            $modes[] = 'return';
        }
        return sprintf('[%s: message="%s" code=%d mode=%s level=%s '.
                       'prefix="%s" info="%s"]',
                       strtolower(get_class($this)), $this->message, $this->code,
                       implode("|", $modes), $levels[$this->level],
                       $this->error_message_prefix,
                       $this->userinfo);
    }
}

/*
 * Local Variables:
 * mode: php
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 */