Merge branch '0.8.x' into invite-enabled

2 files changed, 877 insertions, 0 deletions

diff --git a/extlib/Console/Getopt.php b/extlib/Console/Getopt.php
new file mode 100644
index 000000000..bb9d69ca2
--- /dev/null
+++ b/extlib/Console/Getopt.php
@@ -0,0 +1,290 @@
+<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4: */
+// +----------------------------------------------------------------------+
+// | PHP Version 5                                                        |
+// +----------------------------------------------------------------------+
+// | Copyright (c) 1997-2004 The PHP 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 through the world-wide-web at the following url:           |
+// | 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.               |
+// +----------------------------------------------------------------------+
+// | Author: Andrei Zmievski <andrei@php.net>                             |
+// +----------------------------------------------------------------------+
+//
+// $Id: Getopt.php,v 1.4 2007/06/12 14:58:56 cellog Exp $
+
+require_once 'PEAR.php';
+
+/**
+ * Command-line options parsing class.
+ *
+ * @author Andrei Zmievski <andrei@php.net>
+ *
+ */
+class Console_Getopt {
+    /**
+     * Parses the command-line options.
+     *
+     * The first parameter to this function should be the list of command-line
+     * arguments without the leading reference to the running program.
+     *
+     * The second parameter is a string of allowed short options. Each of the
+     * option letters can be followed by a colon ':' to specify that the option
+     * requires an argument, or a double colon '::' to specify that the option
+     * takes an optional argument.
+     *
+     * The third argument is an optional array of allowed long options. The
+     * leading '--' should not be included in the option name. Options that
+     * require an argument should be followed by '=', and options that take an
+     * option argument should be followed by '=='.
+     *
+     * The return value is an array of two elements: the list of parsed
+     * options and the list of non-option command-line arguments. Each entry in
+     * the list of parsed options is a pair of elements - the first one
+     * specifies the option, and the second one specifies the option argument,
+     * if there was one.
+     *
+     * Long and short options can be mixed.
+     *
+     * Most of the semantics of this function are based on GNU getopt_long().
+     *
+     * @param array  $args           an array of command-line arguments
+     * @param string $short_options  specifies the list of allowed short options
+     * @param array  $long_options   specifies the list of allowed long options
+     *
+     * @return array two-element array containing the list of parsed options and
+     * the non-option arguments
+     *
+     * @access public
+     *
+     */
+    function getopt2($args, $short_options, $long_options = null)
+    {
+        return Console_Getopt::doGetopt(2, $args, $short_options, $long_options);
+    }
+
+    /**
+     * This function expects $args to start with the script name (POSIX-style).
+     * Preserved for backwards compatibility.
+     * @see getopt2()
+     */    
+    function getopt($args, $short_options, $long_options = null)
+    {
+        return Console_Getopt::doGetopt(1, $args, $short_options, $long_options);
+    }
+
+    /**
+     * The actual implementation of the argument parsing code.
+     */
+    function doGetopt($version, $args, $short_options, $long_options = null)
+    {
+        // in case you pass directly readPHPArgv() as the first arg
+        if (PEAR::isError($args)) {
+            return $args;
+        }
+        if (empty($args)) {
+            return array(array(), array());
+        }
+        $opts     = array();
+        $non_opts = array();
+
+        settype($args, 'array');
+
+        if ($long_options) {
+            sort($long_options);
+        }
+
+        /*
+         * Preserve backwards compatibility with callers that relied on
+         * erroneous POSIX fix.
+         */
+        if ($version < 2) {
+            if (isset($args[0]{0}) && $args[0]{0} != '-') {
+                array_shift($args);
+            }
+        }
+
+        reset($args);
+        while (list($i, $arg) = each($args)) {
+
+            /* The special element '--' means explicit end of
+               options. Treat the rest of the arguments as non-options
+               and end the loop. */
+            if ($arg == '--') {
+                $non_opts = array_merge($non_opts, array_slice($args, $i + 1));
+                break;
+            }
+
+            if ($arg{0} != '-' || (strlen($arg) > 1 && $arg{1} == '-' && !$long_options)) {
+                $non_opts = array_merge($non_opts, array_slice($args, $i));
+                break;
+            } elseif (strlen($arg) > 1 && $arg{1} == '-') {
+                $error = Console_Getopt::_parseLongOption(substr($arg, 2), $long_options, $opts, $args);
+                if (PEAR::isError($error))
+                    return $error;
+            } elseif ($arg == '-') {
+                // - is stdin
+                $non_opts = array_merge($non_opts, array_slice($args, $i));
+                break;
+            } else {
+                $error = Console_Getopt::_parseShortOption(substr($arg, 1), $short_options, $opts, $args);
+                if (PEAR::isError($error))
+                    return $error;
+            }
+        }
+
+        return array($opts, $non_opts);
+    }
+
+    /**
+     * @access private
+     *
+     */
+    function _parseShortOption($arg, $short_options, &$opts, &$args)
+    {
+        for ($i = 0; $i < strlen($arg); $i++) {
+            $opt = $arg{$i};
+            $opt_arg = null;
+
+            /* Try to find the short option in the specifier string. */
+            if (($spec = strstr($short_options, $opt)) === false || $arg{$i} == ':')
+            {
+                return PEAR::raiseError("Console_Getopt: unrecognized option -- $opt");
+            }
+
+            if (strlen($spec) > 1 && $spec{1} == ':') {
+                if (strlen($spec) > 2 && $spec{2} == ':') {
+                    if ($i + 1 < strlen($arg)) {
+                        /* Option takes an optional argument. Use the remainder of
+                           the arg string if there is anything left. */
+                        $opts[] = array($opt, substr($arg, $i + 1));
+                        break;
+                    }
+                } else {
+                    /* Option requires an argument. Use the remainder of the arg
+                       string if there is anything left. */
+                    if ($i + 1 < strlen($arg)) {
+                        $opts[] = array($opt,  substr($arg, $i + 1));
+                        break;
+                    } else if (list(, $opt_arg) = each($args)) {
+                        /* Else use the next argument. */;
+                        if (Console_Getopt::_isShortOpt($opt_arg) || Console_Getopt::_isLongOpt($opt_arg)) {
+                            return PEAR::raiseError("Console_Getopt: option requires an argument -- $opt");
+                        }
+                    } else {
+                        return PEAR::raiseError("Console_Getopt: option requires an argument -- $opt");
+                    }
+                }
+            }
+
+            $opts[] = array($opt, $opt_arg);
+        }
+    }
+
+    /**
+     * @access private
+     *
+     */
+    function _isShortOpt($arg)
+    {
+        return strlen($arg) == 2 && $arg[0] == '-' && preg_match('/[a-zA-Z]/', $arg[1]);
+    }
+
+    /**
+     * @access private
+     *
+     */
+    function _isLongOpt($arg)
+    {
+        return strlen($arg) > 2 && $arg[0] == '-' && $arg[1] == '-' &&
+            preg_match('/[a-zA-Z]+$/', substr($arg, 2));
+    }
+
+    /**
+     * @access private
+     *
+     */
+    function _parseLongOption($arg, $long_options, &$opts, &$args)
+    {
+        @list($opt, $opt_arg) = explode('=', $arg, 2);
+        $opt_len = strlen($opt);
+
+        for ($i = 0; $i < count($long_options); $i++) {
+            $long_opt  = $long_options[$i];
+            $opt_start = substr($long_opt, 0, $opt_len);
+            $long_opt_name = str_replace('=', '', $long_opt);
+
+            /* Option doesn't match. Go on to the next one. */
+            if ($long_opt_name != $opt) {
+                continue;
+            }
+
+            $opt_rest  = substr($long_opt, $opt_len);
+
+            /* Check that the options uniquely matches one of the allowed
+               options. */
+            if ($i + 1 < count($long_options)) {
+                $next_option_rest = substr($long_options[$i + 1], $opt_len);
+            } else {
+                $next_option_rest = '';
+            }
+            if ($opt_rest != '' && $opt{0} != '=' &&
+                $i + 1 < count($long_options) &&
+                $opt == substr($long_options[$i+1], 0, $opt_len) &&
+                $next_option_rest != '' &&
+                $next_option_rest{0} != '=') {
+                return PEAR::raiseError("Console_Getopt: option --$opt is ambiguous");
+            }
+
+            if (substr($long_opt, -1) == '=') {
+                if (substr($long_opt, -2) != '==') {
+                    /* Long option requires an argument.
+                       Take the next argument if one wasn't specified. */;
+                    if (!strlen($opt_arg) && !(list(, $opt_arg) = each($args))) {
+                        return PEAR::raiseError("Console_Getopt: option --$opt requires an argument");
+                    }
+                    if (Console_Getopt::_isShortOpt($opt_arg) || Console_Getopt::_isLongOpt($opt_arg)) {
+                        return PEAR::raiseError("Console_Getopt: option requires an argument --$opt");
+                    }
+                }
+            } else if ($opt_arg) {
+                return PEAR::raiseError("Console_Getopt: option --$opt doesn't allow an argument");
+            }
+
+            $opts[] = array('--' . $opt, $opt_arg);
+            return;
+        }
+
+        return PEAR::raiseError("Console_Getopt: unrecognized option --$opt");
+    }
+
+    /**
+    * Safely read the $argv PHP array across different PHP configurations.
+    * Will take care on register_globals and register_argc_argv ini directives
+    *
+    * @access public
+    * @return mixed the $argv PHP array or PEAR error if not registered
+    */
+    function readPHPArgv()
+    {
+        global $argv;
+        if (!is_array($argv)) {
+            if (!@is_array($_SERVER['argv'])) {
+                if (!@is_array($GLOBALS['HTTP_SERVER_VARS']['argv'])) {
+                    return PEAR::raiseError("Console_Getopt: Could not read cmd args (register_argc_argv=Off?)");
+                }
+                return $GLOBALS['HTTP_SERVER_VARS']['argv'];
+            }
+            return $_SERVER['argv'];
+        }
+        return $argv;
+    }
+
+}
+
+?>
diff --git a/extlib/System/Command.php b/extlib/System/Command.php
new file mode 100644
index 000000000..f5c3ec6b9
--- /dev/null
+++ b/extlib/System/Command.php
@@ -0,0 +1,587 @@
+<?php
+// {{{ license
+
+// +----------------------------------------------------------------------+
+// | PHP Version 4.0                                                      |
+// +----------------------------------------------------------------------+
+// | Copyright (c) 1997-2003 The PHP Group                                |
+// +----------------------------------------------------------------------+
+// | This source file is subject to version 2.02 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/2_02.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.               |
+// +----------------------------------------------------------------------+
+// | Author: Anders Johannsen <anders@johannsen.com>                      |
+// | Author: Dan Allen <dan@mojavelinux.com>
+// +----------------------------------------------------------------------+
+
+// $Id: Command.php,v 1.9 2007/04/20 21:08:48 cconstantine Exp $
+
+// }}}
+// {{{ includes
+
+require_once 'PEAR.php';
+require_once 'System.php';
+
+// }}}
+// {{{ constants
+
+define('SYSTEM_COMMAND_OK',                 1);
+define('SYSTEM_COMMAND_ERROR',             -1);
+define('SYSTEM_COMMAND_NO_SHELL',          -2);
+define('SYSTEM_COMMAND_INVALID_SHELL',     -3);
+define('SYSTEM_COMMAND_TMPDIR_ERROR',      -4);
+define('SYSTEM_COMMAND_INVALID_OPERATOR',  -5);
+define('SYSTEM_COMMAND_INVALID_COMMAND',   -6);
+define('SYSTEM_COMMAND_OPERATOR_PLACEMENT',-7);
+define('SYSTEM_COMMAND_COMMAND_PLACEMENT', -8);
+define('SYSTEM_COMMAND_NOHUP_MISSING',     -9);
+define('SYSTEM_COMMAND_NO_OUTPUT',        -10);
+define('SYSTEM_COMMAND_STDERR',           -11);
+define('SYSTEM_COMMAND_NONZERO_EXIT',     -12);
+
+// }}}
+
+// {{{ class System_Command
+
+/**
+ * The System_Command:: class implements an abstraction for various ways 
+ * of executing commands (directly using the backtick operator,
+ * as a background task after the script has terminated using
+ * register_shutdown_function() or as a detached process using nohup).
+ *
+ * @author  Anders Johannsen <anders@johannsen.com>
+ * @author  Dan Allen <dan@mojavelinux.com>
+ * @version $Revision: 1.9 $
+ */
+
+// }}}
+class System_Command {
+    // {{{ properties
+
+    /**
+     * Array of settings used when creating the shell command
+     *
+     * @var array
+     * @access private
+     */
+    var $options = array();
+
+    /**
+     * Array of available shells to use to execute the command
+     *
+     * @var array
+     * @access private
+     */
+    var $shells = array();
+
+    /**
+     * Array of available control operators used between commands
+     *
+     * @var array
+     * @access private
+     */
+    var $controlOperators = array();
+
+    /**
+     * The system command to be executed
+     *
+     * @var string
+     * @access private
+     */
+    var $systemCommand = null;
+
+    /**
+     * Previously added part to the command string
+     *
+     * @var string
+     * @access private
+     */
+    var $previousElement = null;
+
+    /**
+     * Directory for writing stderr output
+     *
+     * @var string
+     * @access private
+     */
+    var $tmpDir = null;
+
+    /**
+     * To allow the pear error object to accumulate when building
+     * the command, we use the command status to keep track when
+     * a pear error is raised
+     *
+     * @var int
+     * @access private
+     */
+    var $commandStatus = 0;
+    
+    /**
+     * Hold initialization PEAR_Error
+     *
+     * @var object
+     * @access private
+     **/
+    var $_initError = null;
+        
+    // }}}
+    // {{{ constructor
+
+    /**
+     * Class constructor
+     * 
+     * Defines all necessary constants and sets defaults
+     * 
+     * @access public
+     */
+    function System_Command($in_shell = null)
+    {
+        // Defining constants
+        $this->options = array(
+            'SEQUENCE'   => true,
+            'SHUTDOWN'   => false,
+            'SHELL'      => $this->which($in_shell),
+            'OUTPUT'     => true,
+            'NOHUP'      => false,
+            'BACKGROUND' => false,
+            'STDERR'     => false
+        );
+
+        // prepare the available control operators
+        $this->controlOperators = array(
+            'PIPE'  => '|',
+            'AND'   => '&&',
+            'OR'    => '||',
+            'GROUP' => ';',
+            'LFIFO' => '<',
+            'RFIFO' => '>',
+        );
+                
+        // List of allowed/available shells
+        $this->shells = array(
+            'sh',
+            'bash',
+            'zsh',
+            'tcsh',
+            'csh',
+            'ash',
+            'sash',
+            'esh',
+            'ksh'
+        );
+                                   
+        // Find the first available shell
+        if (empty($this->options['SHELL'])) {
+            foreach ($this->shells as $shell) {
+                if ($this->options['SHELL'] = $this->which($shell)) {
+                    break;
+                }
+            }
+
+            // see if we still have no shell
+            if (empty($this->options['SHELL'])) {
+            	$this->_initError =& PEAR::raiseError(null, SYSTEM_COMMAND_NO_SHELL, null, E_USER_WARNING, null, 'System_Command_Error', true);
+                return;
+            }
+        }
+
+        // Caputre a temporary directory for capturing stderr from commands
+        $this->tmpDir = System::tmpdir();
+        if (!System::mkDir("-p {$this->tmpDir}")) {
+            $this->_initError =& PEAR::raiseError(null, SYSTEM_COMMAND_TMPDIR_ERROR, null, E_USER_WARNING, null, 'System_Command_Error', true);
+            return;
+        }
+    }
+        
+    // }}}
+    // {{{ setOption()
+
+    /**
+     * Sets the value for an option. Each option should be set to true
+     * or false; except the 'SHELL' option which should be a string
+     * naming a shell. The options are:
+     * 
+     * 'SEQUENCE'   Allow a sequence command or not (right now this is always on);
+     *
+     * 'SHUTDOWN'   Execute commands via a shutdown function;
+     *
+     * 'SHELL'      Path to shell;
+     *
+     * 'OUTPUT'     Output stdout from process;
+     *
+     * 'NOHUP'      Use nohup to detach process;
+     *
+     * 'BACKGROUND' Run as a background process with &;
+     *
+     * 'STDERR'     Output on stderr will raise an error, even if
+     *              the command's exit value is zero. The output from
+     *              stderr can be retrieved using the getDebugInfo()
+     *              method of the Pear_ERROR object returned by
+     *              execute().;
+     *
+     * @param string $in_option is a case-sensitive string,
+     *                          corresponding to the option
+     *                          that should be changed
+     * @param mixed $in_setting is the new value for the option
+     * @access public
+     * @return bool true if succes, else false
+     */
+    function setOption($in_option, $in_setting)
+    {
+    	if ($this->_initError) {
+            return $this->_initError;
+        }
+
+        $option = strtoupper($in_option);
+
+        if (!isset($this->options[$option])) {
+            PEAR::raiseError(null, SYSTEM_COMMAND_ERROR, null, E_USER_NOTICE, null, 'System_Command_Error', true);
+            return false;
+        }
+                
+        switch ($option) {
+            case 'OUTPUT':
+            case 'SHUTDOWN':
+            case 'SEQUENCE':
+            case 'BACKGROUND':
+            case 'STDERR':
+                $this->options[$option] = !empty($in_setting);
+                return true;
+            break;
+                
+            case 'SHELL':
+                if (($shell = $this->which($in_setting)) !== false) {
+                    $this->options[$option] = $shell;
+                    return true;
+                } 
+                else {
+                    PEAR::raiseError(null, SYSTEM_COMMAND_NO_SHELL, null, E_USER_NOTICE, $in_setting, 'System_Command_Error', true);
+                    return false;
+                }
+            break;
+                        
+            case 'NOHUP':
+                if (empty($in_setting)) {
+                    $this->options[$option] = false;
+                } 
+                else if ($location = $this->which('nohup')) {
+                    $this->options[$option] = $location;
+                } 
+                else {
+                    PEAR::raiseError(null, SYSTEM_COMMAND_NOHUP_MISSING, null, E_USER_NOTICE, null, 'System_Command_Error', true);
+                    return false;
+                }
+            break;
+        }
+    }
+    
+    // }}}
+    // {{{ pushCommand()
+
+    /**
+     * Used to push a command onto the running command to be executed
+     *
+     * @param  string $in_command binary to be run
+     * @param  string $in_argument either an option or argument value, to be handled appropriately
+     * @param  string $in_argument
+     * @param  ...
+     *
+     * @access public
+     * @return boolean true on success {or System_Command_Error Exception}
+     */
+    function pushCommand($in_command)
+    {
+    	if ($this->_initError) {
+            return $this->_initError;
+        }
+        
+        if (!is_null($this->previousElement) && !in_array($this->previousElement, $this->controlOperators)) {
+            $this->commandStatus = -1;
+            $error = PEAR::raiseError(null, SYSTEM_COMMAND_COMMAND_PLACEMENT, null, E_USER_WARNING, null, 'System_Command_Error', true);
+        }
+
+        // check for error here
+        $command = escapeshellcmd($this->which($in_command));
+        if ($command === false) {
+            $error = PEAR::raiseError(null, SYSTEM_COMMAND_INVALID_COMMAND, null, E_USER_WARNING, null, 'System_Command_Error', true);
+        }
+
+        $argv = func_get_args();
+        array_shift($argv);
+        foreach($argv as $arg) {
+            if (strpos($arg, '-') === 0) {
+                $command .= ' ' . $arg; 
+            }
+            elseif ($arg != '') {
+                $command .= ' ' . escapeshellarg($arg);
+            }
+        }
+
+        $this->previousElement = $command;
+        $this->systemCommand .= $command;
+
+        return isset($error) ? $error : true;
+    }
+
+    // }}}
+    // {{{ pushOperator()
+
+    /**
+     * Used to push an operator onto the running command to be executed
+     *
+     * @param  string $in_operator Either string reprentation of operator or system character
+     *
+     * @access public
+     * @return boolean true on success {or System_Command_Error Exception}
+     */
+    function pushOperator($in_operator)
+    {
+    	if ($this->_initError) {
+            return $this->_initError;
+        }
+
+        $operator = isset($this->controlOperators[$in_operator]) ? $this->controlOperators[$in_operator] : $in_operator;
+
+        if (is_null($this->previousElement) || in_array($this->previousElement, $this->controlOperators)) {
+            $this->commandStatus = -1;
+            $error = PEAR::raiseError(null, SYSTEM_COMMAND_OPERATOR_PLACEMENT, null, E_USER_WARNING, null, 'System_Command_Error', true);
+        }
+        elseif (!in_array($operator, $this->controlOperators)) {
+            $this->commandStatus = -1;
+            $error = PEAR::raiseError(null, SYSTEM_COMMAND_INVALID_OPERATOR, null, E_USER_WARNING, $operator, 'System_Command_Error', true);
+        }
+
+        $this->previousElement = $operator;
+        $this->systemCommand .= ' ' . $operator . ' ';
+        return isset($error) ? $error : true;
+    }
+
+    // }}}
+    // {{{ execute()
+
+    /**
+     * Executes the code according to given options
+     *
+     * @return bool true if success {or System_Command_Exception}
+     *
+     * @access public
+     */
+    function execute() 
+    {
+    	if ($this->_initError) {
+            return $this->_initError;
+        }
+
+        // if the command is empty or if the last element was a control operator, we can't continue
+        if (is_null($this->previousElement) || $this->commandStatus == -1 || in_array($this->previousElement, $this->controlOperators)) {
+            return PEAR::raiseError(null, SYSTEM_COMMAND_INVALID_COMMAND, null, E_USER_WARNING, $this->systemCommand, 'System_Command_Error', true);
+        }
+
+        // Warning about impossible mix of options
+        if (!empty($this->options['OUTPUT'])) {
+            if (!empty($this->options['SHUTDOWN']) || !empty($this->options['NOHUP'])) {
+                return PEAR::raiseError(null, SYSTEM_COMMAND_NO_OUTPUT, null, E_USER_WARNING, null, 'System_Command_Error', true);
+            }
+        }
+                
+        // if this is not going to stdout, then redirect to /dev/null
+        if (empty($this->options['OUTPUT'])) {
+            $this->systemCommand .= ' >/dev/null';
+        }
+                
+        $suffix = '';
+        // run a command immune to hangups, with output to a non-tty
+        if (!empty($this->options['NOHUP'])) {
+            $this->systemCommand = $this->options['NOHUP'] . $this->systemCommand;
+        }
+        // run a background process (only if not nohup)
+        elseif (!empty($this->options['BACKGROUND'])) {
+            $suffix = ' &';
+        }
+                
+        // Register to be run on shutdown
+        if (!empty($this->options['SHUTDOWN'])) {
+            $line = "system(\"{$this->systemCommand}$suffix\");";
+            $function = create_function('', $line);
+            register_shutdown_function($function);
+            return true;
+        } 
+        else {
+            // send stderr to a file so that we can reap the error message
+            $tmpFile = tempnam($this->tmpDir, 'System_Command-');
+            $this->systemCommand .= ' 2>' . $tmpFile . $suffix;
+            $shellPipe = $this->which('echo') . ' ' . escapeshellarg($this->systemCommand) . ' | ' . $this->options['SHELL'];
+            exec($shellPipe, $result, $returnVal);
+
+            if ($returnVal !== 0) {
+                // command returned nonzero; that's always an error
+                $return = PEAR::raiseError(null, SYSTEM_COMMAND_NONZERO_EXIT, null, E_USER_WARNING, null, 'System_Command_Error', true);
+            }
+            else if (!$this->options['STDERR']) {
+                // caller does not care about stderr; return success
+                $return = implode("\n", $result);
+            }
+            else {
+                // our caller cares about stderr; check stderr output
+                clearstatcache();
+                if (filesize($tmpFile) > 0) {
+                    // the command actually wrote to stderr
+                    $stderr_output = file_get_contents($tmpFile);
+                    $return = PEAR::raiseError(null, SYSTEM_COMMAND_STDERR, null, E_USER_WARNING, $stderr_output, 'System_Command_Error', true);
+                } else {
+                    // total success; return stdout gathered by exec()
+                    $return = implode("\n", $result);
+                }
+            }
+
+            unlink($tmpFile);
+            return $return;
+        }
+    }
+
+    // }}}
+    // {{{ which()
+
+    /**
+     * Functionality similiar to unix 'which'. Searches the path
+     * for the specified program. 
+     *
+     * @param $cmd name of the executable to search for 
+     *
+     * @access private
+     * @return string returns the full path if found, false if not
+     */
+    function which($in_cmd)
+    {
+        // only pass non-empty strings to System::which()
+        if (!is_string($in_cmd) || '' === $in_cmd) {
+            return(false);
+        }
+
+        // explicitly pass false as fallback value
+        return System::which($in_cmd, false);
+    }   
+
+    // }}}
+    // {{{ reset()
+
+    /**
+     * Prepare for a new command to be built
+     *
+     * @access public
+     * @return void
+     */
+    function reset()
+    {
+        $this->previousElement = null;
+        $this->systemCommand = null;
+        $this->commandStatus = 0;
+    }
+
+    // }}}
+    // {{{ errorMessage()
+
+    /**
+     * Return a textual error message for a System_Command error code
+     *
+     * @param integer error code
+     *
+     * @return string error message, or false if the error code was
+     * not recognized
+     */
+    function errorMessage($in_value)
+    {
+        static $errorMessages;
+        if (!isset($errorMessages)) {
+            $errorMessages = array(
+                SYSTEM_COMMAND_OK                     => 'no error',
+                SYSTEM_COMMAND_ERROR                  => 'unknown error',
+                SYSTEM_COMMAND_NO_SHELL               => 'no shell found',
+                SYSTEM_COMMAND_INVALID_SHELL          => 'invalid shell',
+                SYSTEM_COMMAND_TMPDIR_ERROR           => 'could not create temporary directory',
+                SYSTEM_COMMAND_INVALID_OPERATOR       => 'control operator invalid',
+                SYSTEM_COMMAND_INVALID_COMMAND        => 'invalid system command',
+                SYSTEM_COMMAND_OPERATOR_PLACEMENT     => 'invalid placement of control operator',
+                SYSTEM_COMMAND_COMMAND_PLACEMENT      => 'invalid placement of command',
+                SYSTEM_COMMAND_NOHUP_MISSING          => 'nohup not found on system',
+                SYSTEM_COMMAND_NO_OUTPUT              => 'output not allowed',
+                SYSTEM_COMMAND_STDERR                 => 'command wrote to stderr',
+                SYSTEM_COMMAND_NONZERO_EXIT           => 'non-zero exit value from command',
+            );
+        }
+
+        if (System_Command::isError($in_value)) {
+            $in_value = $in_value->getCode();
+        }
+
+        return isset($errorMessages[$in_value]) ? $errorMessages[$in_value] : $errorMessages[SYSTEM_COMMAND_ERROR];
+    }
+
+    // }}}
+    // {{{ isError()
+
+    /**
+     * Tell whether a result code from a System_Command method is an error
+     *
+     * @param int result code
+     *
+     * @return bool whether $in_value is an error
+     *
+     * @access public
+     */
+    function isError($in_value)
+    {
+        return (is_object($in_value) &&
+                (strtolower(get_class($in_value)) == 'system_command_error' ||
+                 is_subclass_of($in_value, 'system_command_error')));
+    }
+    
+    // }}}
+}
+
+// {{{ class System_Command_Error
+
+/**
+ * System_Command_Error constructor.
+ *
+ * @param mixed      System_Command error code, or string with error message.
+ * @param integer    what "error mode" to operate in
+ * @param integer    what error level to use for $mode & PEAR_ERROR_TRIGGER
+ * @param mixed      additional debug info, such as the last query
+ *
+ * @access public
+ *
+ * @see PEAR_Error
+ */
+
+// }}}
+class System_Command_Error extends PEAR_Error
+{
+    // {{{ properties
+
+    /**
+     * Message in front of the error message
+     * @var string $error_message_prefix
+     */
+    var $error_message_prefix = 'System_Command Error: ';
+
+    // }}}
+    // {{{ constructor
+
+    function System_Command_Error($code = SYSTEM_COMMAND_ERROR, $mode = PEAR_ERROR_RETURN,
+              $level = E_USER_NOTICE, $debuginfo = null)
+    {
+        if (is_int($code)) {
+            $this->PEAR_Error(System_Command::errorMessage($code), $code, $mode, $level, $debuginfo);
+        } else {
+            $this->PEAR_Error("Invalid error code: $code", SYSTEM_COMMAND_ERROR, $mode, $level, $debuginfo);
+        }
+    }
+    
+    // }}}
+}
+?>