/include/PEAR/Exception.php

<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 foldmethod=marker: */
// +----------------------------------------------------------------------+
// | PEAR_Exception                                                       |
// +----------------------------------------------------------------------+
// | Copyright (c) 2004 The PEAR Group                                    |
// +----------------------------------------------------------------------+
// | This source file is subject to version 3.0 of the PHP license,       |
// | that is bundled with this package in the file LICENSE, and is        |
// | available at through the world-wide-web at                           |
// | http://www.php.net/license/3_0.txt.                                  |
// | If you did not receive a copy of the PHP license and are unable to   |
// | obtain it through the world-wide-web, please send a note to          |
// | license@php.net so we can mail you a copy immediately.               |
// +----------------------------------------------------------------------+
// | Authors: Tomas V.V.Cox <cox@idecnet.com>                             |
// |          Hans Lellelid <hans@velum.net>                              |
// |          Bertrand Mansion <bmansion@mamasam.com>                     |
// |          Greg Beaver <cellog@php.net>                                |
// +----------------------------------------------------------------------+
//
// $Id: Exception.php,v 1.4.2.1 2004/10/19 04:13:16 cellog Exp $


/**
 * Base PEAR_Exception Class
 *
 * WARNING: This code should be considered stable, but the API is
 * subject to immediate and drastic change, so API stability is
 * at best alpha
 *
 * 1) Features:
 *
 * - Nestable exceptions (throw new PEAR_Exception($msg, $prev_exception))
 * - Definable triggers, shot when exceptions occur
 * - Pretty and informative error messages
 * - Added more context info available (like class, method or cause)
 * - cause can be a PEAR_Exception or an array of mixed
 *   PEAR_Exceptions/PEAR_ErrorStack warnings
 * - callbacks for specific exception classes and their children
 *
 * 2) Ideas:
 *
 * - Maybe a way to define a 'template' for the output
 *
 * 3) Inherited properties from PHP Exception Class:
 *
 * protected $message
 * protected $code
 * protected $line
 * protected $file
 * private   $trace
 *
 * 4) Inherited methods from PHP Exception Class:
 *
 * __clone
 * __construct
 * getMessage
 * getCode
 * getFile
 * getLine
 * getTraceSafe
 * getTraceSafeAsString
 * __toString
 *
 * 5) Usage example
 *
 * <code>
 *  require_once 'PEAR/Exception.php';
 *
 *  class Test {
 *     function foo() {
 *         throw new PEAR_Exception('Error Message', ERROR_CODE);
 *     }
 *  }
 *
 *  function myLogger($pear_exception) {
 *     echo $pear_exception->getMessage();
 *  }
 *  // each time a exception is thrown the 'myLogger' will be called
 *  // (its use is completely optional)
 *  PEAR_Exception::addObserver('myLogger');
 *  $test = new Test;
 *  try {
 *     $test->foo();
 *  } catch (PEAR_Exception $e) {
 *     print $e;
 *  }
 * </code>
 *
 * @since PHP 5
 * @package PEAR
 * @version $Revision: 1.4.2.1 $
 * @author Tomas V.V.Cox <cox@idecnet.com>
 * @author Hans Lellelid <hans@velum.net>
 * @author Bertrand Mansion <bmansion@mamasam.com>
 *
 */
class PEAR_Exception extends Exception
{
    const OBSERVER_PRINT = -2;
    const OBSERVER_TRIGGER = -4;
    const OBSERVER_DIE = -8;
    protected $cause;
    private static $_observers = array();
    private static $_uniqueid = 0;
    private $_trace;

    /**
     * Supported signatures:
     * PEAR_Exception(string $message);
     * PEAR_Exception(string $message, int $code);
     * PEAR_Exception(string $message, Exception $cause);
     * PEAR_Exception(string $message, Exception $cause, int $code);
     * PEAR_Exception(string $message, array $causes);
     * PEAR_Exception(string $message, array $causes, int $code);
     */
    public function __construct($message, $p2 = null, $p3 = null)
    {
        if (is_int($p2)) {
            $code = $p2;
            $this->cause = null;
        } elseif ($p2 instanceof Exception || is_array($p2)) {
            $code = $p3;
            if (is_array($p2) && isset($p2['message'])) {
                // fix potential problem of passing in a single warning
                $p2 = array($p2);
            }
            $this->cause = $p2;
        } else {
        $code = null;
            $this->cause = null;
        }
        parent::__construct($message, $code);
        $this->signal();
    }

    /**
     * @param mixed $callback  - A valid php callback, see php func is_callable()
     *                         - A PEAR_Exception::OBSERVER_* constant
     *                         - An array(const PEAR_Exception::OBSERVER_*,
     *                           mixed $options)
     * @param string $label    The name of the observer. Use this if you want
     *                         to remove it later with removeObserver()
     */
    public static function addObserver($callback, $label = 'default')
    {
        self::$_observers[$label] = $callback;
    }

    public static function removeObserver($label = 'default')
    {
        unset(self::$_observers[$label]);
    }

    /**
     * @return int unique identifier for an observer
     */
    public static function getUniqueId()
    {
        return self::$_uniqueid++;
    }

    private function signal()
    {
        foreach (self::$_observers as $func) {
            if (is_callable($func)) {
                call_user_func($func, $this);
                continue;
            }
            settype($func, 'array');
            switch ($func[0]) {
                case self::OBSERVER_PRINT :
                    $f = (isset($func[1])) ? $func[1] : '%s';
                    printf($f, $this->getMessage());
                    break;
                case self::OBSERVER_TRIGGER :
                    $f = (isset($func[1])) ? $func[1] : E_USER_NOTICE;
                    trigger_error($this->getMessage(), $f);
                    break;
                case self::OBSERVER_DIE :
                    $f = (isset($func[1])) ? $func[1] : '%s';
                    die(printf($f, $this->getMessage()));
                    break;
                default:
                    trigger_error('invalid observer type', E_USER_WARNING);
            }
        }
    }

    /**
     * Return specific error information that can be used for more detailed
     * error messages or translation.
     *
     * This method may be overridden in child exception classes in order
     * to add functionality not present in PEAR_Exception and is a placeholder
     * to define API
     *
     * The returned array must be an associative array of parameter => value like so:
     * <pre>
     * array('name' => $name, 'context' => array(...))
     * </pre>
     * @return array
     */
    public function getErrorData()
    {
        return array();
    }

    /**
     * Returns the exception that caused this exception to be thrown
     * @access public
     * @return Exception|array The context of the exception
     */
    public function getCause()
    {
        return $this->cause;
    }

    /**
     * Function must be public to call on caused exceptions
     * @param array
     */
    public function getCauseMessage(&$causes)
    {
        $trace = $this->getTraceSafe();
        $causes[] = array('class'   => get_class($this),
                          'message' => $this->message,
                          'file'    => $trace[0]['file'],
                          'line'    => $trace[0]['line']);
        if ($this->cause instanceof PEAR_Exception) {
            $this->cause->getCauseMessage($causes);
        }
        if (is_array($this->cause)) {
            foreach ($this->cause as $cause) {
                if ($cause instanceof PEAR_Exception) {
                    $cause->getCauseMessage($causes);
                } elseif (is_array($cause) && isset($cause['message'])) {
                    // PEAR_ErrorStack warning
                    $causes[] = array(
                        'class' => $cause['package'],
                        'message' => $cause['message'],
                        'file' => isset($cause['context']['file']) ?
                                            $cause['context']['file'] :
                                            'unknown',
                        'line' => isset($cause['context']['line']) ?
                                            $cause['context']['line'] :
                                            'unknown',
                    );
                }
            }
        }
    }

    public function getTraceSafe()
    {   
        if (!isset($this->_trace)) {
            $this->_trace = $this->getTrace();
            if (empty($this->_trace)) {
                $backtrace = debug_backtrace();
                $this->_trace = array($backtrace[count($backtrace)-1]);
            }
        }
        return $this->_trace;
    }

    public function getErrorClass()
    {
        $trace = $this->getTraceSafe();
        return $trace[0]['class'];
    }

    public function getErrorMethod()
    {
        $trace = $this->getTraceSafe();
        return $trace[0]['function'];
    }

    public function __toString()
    {
        if (isset($_SERVER['REQUEST_URI'])) {
            return $this->toHtml();
        }
        return $this->toText();
        }

    public function toHtml()
    {
        $trace = $this->getTraceSafe();
        $causes = array();
        $this->getCauseMessage($causes);
        $html =  '<table border="1" cellspacing="0">' . "\n";
        foreach ($causes as $i => $cause) {
            $html .= '<tr><td colspan="3" bgcolor="#ff9999">'
               . str_repeat('-', $i) . ' <b>' . $cause['class'] . '</b>: '
               . htmlspecialchars($cause['message']) . ' in <b>' . $cause['file'] . '</b> '
               . 'on line <b>' . $cause['line'] . '</b>'
               . "</td></tr>\n";
        }
        $html .= '<tr><td colspan="3" bgcolor="#aaaaaa" align="center"><b>Exception trace</b></td></tr>' . "\n"
               . '<tr><td align="center" bgcolor="#cccccc" width="20"><b>#</b></td>'
               . '<td align="center" bgcolor="#cccccc"><b>Function</b></td>'
               . '<td align="center" bgcolor="#cccccc"><b>Location</b></td></tr>' . "\n";

        foreach ($trace as $k => $v) {
            $html .= '<tr><td align="center">' . $k . '</td>'
                   . '<td>';
            if (!empty($v['class'])) {
                $html .= $v['class'] . $v['type'];
            }
            $html .= $v['function'];
            $args = array();
            if (!empty($v['args'])) {
                foreach ($v['args'] as $arg) {
                    if (is_null($arg)) $args[] = 'null';
                    elseif (is_array($arg)) $args[] = 'Array';
                    elseif (is_object($arg)) $args[] = 'Object('.get_class($arg).')';
                    elseif (is_bool($arg)) $args[] = $arg ? 'true' : 'false';
                    elseif (is_int($arg) || is_double($arg)) $args[] = $arg;
                    else {
                        $arg = (string)$arg;
                        $str = htmlspecialchars(substr($arg, 0, 16));
                        if (strlen($arg) > 16) $str .= '&hellip;';
                        $args[] = "'" . $str . "'";
                    }
                }
            }
            $html .= '(' . implode(', ',$args) . ')'
                   . '</td>'
                   . '<td>' . $v['file'] . ':' . $v['line'] . '</td></tr>' . "\n";
        }
        $html .= '<tr><td align="center">' . ($k+1) . '</td>'
               . '<td>{main}</td>'
               . '<td>&nbsp;</td></tr>' . "\n"
               . '</table>';
        return $html;
    }

    public function toText()
    {
        $causes = array();
        $this->getCauseMessage($causes);
        $causeMsg = '';
        foreach ($causes as $i => $cause) {
            $causeMsg .= str_repeat(' ', $i) . $cause['class'] . ': '
                   . $cause['message'] . ' in ' . $cause['file']
                   . ' on line ' . $cause['line'] . "\n";
        }
        return $causeMsg . $this->getTraceAsString();
    }
}

?>