functions/plugin.php

   1 <?php
   2
   3 /**
   4  * plugin.php
   5  *
   6  * Copyright (c) 1999-2003 The SquirrelMail Project Team
   7  * Licensed under the GNU GPL. For full terms see the file COPYING.
   8  *
   9  * This file provides the framework for a plugin architecture.
  10  *
  11  * Documentation on how to write plugins might show up some time.
  12  *
  13  * $Id$
  14  * @package squirrelmail
  15  */
  16
  17 /** Everything needs global.. */
  18 require_once(SM_PATH . 'functions/global.php');
  19
  20 global $squirrelmail_plugin_hooks;
  21 $squirrelmail_plugin_hooks = array();
  22
  23 /**
  24  * This function adds a plugin.
  25  * @param string $name Internal plugin name (ie. delete_move_next)
  26  * @return void
  27  */
  28 function use_plugin ($name) {
  29     if (file_exists(SM_PATH . "plugins/$name/setup.php")) {
  30         include_once(SM_PATH . "plugins/$name/setup.php");
  31         $function = "squirrelmail_plugin_init_$name";
  32         if (function_exists($function)) {
  33             $function();
  34         }
  35     }
  36 }
  37
  38 /**
  39  * This function executes a hook.
  40  * @param string $name Name of hook to fire
  41  * @return mixed $data
  42  */
  43 function do_hook ($name) {
  44     global $squirrelmail_plugin_hooks;
  45     $data = func_get_args();
  46     $ret = '';
  47
  48     if (isset($squirrelmail_plugin_hooks[$name])
  49           && is_array($squirrelmail_plugin_hooks[$name])) {
  50         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  51             /* Add something to set correct gettext domain for plugin. */
  52             if (function_exists($function)) {
  53                 $function($data);
  54             }
  55         }
  56     }
  57
  58     /* Variable-length argument lists have a slight problem when */
  59     /* passing values by reference. Pity. This is a workaround.  */
  60     return $data;
  61 }
  62
  63 /* This function executes a hook. */
  64 function do_hook_function($name,$parm=NULL) {
  65     global $squirrelmail_plugin_hooks;
  66     $ret = '';
  67
  68     if (isset($squirrelmail_plugin_hooks[$name])
  69           && is_array($squirrelmail_plugin_hooks[$name])) {
  70         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  71             /* Add something to set correct gettext domain for plugin. */
  72             if (function_exists($function)) {
  73                 $ret = $function($parm);
  74             }
  75         }
  76     }
  77
  78     /* Variable-length argument lists have a slight problem when */
  79     /* passing values by reference. Pity. This is a workaround.  */
  80     return $ret;
  81 }
  82
  83 /* This function executes a hook. */
  84 function concat_hook_function($name,$parm=NULL) {
  85     global $squirrelmail_plugin_hooks;
  86     $ret = '';
  87
  88     if (isset($squirrelmail_plugin_hooks[$name])
  89           && is_array($squirrelmail_plugin_hooks[$name])) {
  90         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  91             /* Concatenate results from hook. */
  92             if (function_exists($function)) {
  93                 $ret .= $function($parm);
  94             }
  95         }
  96     }
  97
  98     /* Variable-length argument lists have a slight problem when */
  99     /* passing values by reference. Pity. This is a workaround.  */
 100     return $ret;
 101 }
 102
 103 /**
 104  * This function is used for hooks which are to return true or
 105  * false. If $priority is > 0, any one or more trues will override
 106  * any falses. If $priority < 0, then one or more falses will
 107  * override any trues.
 108  * Priority 0 means majority rules.  Ties will be broken with $tie */
 109 function boolean_hook_function($name,$parm=NULL,$priority=0,$tie=false) {
 110     global $squirrelmail_plugin_hooks;
 111     $yea = 0;
 112     $nay = 0;
 113     $ret = $tie;
 114
 115     if (isset($squirrelmail_plugin_hooks[$name]) &&
 116         is_array($squirrelmail_plugin_hooks[$name])) {
 117
 118         /* Loop over the plugins that registered the hook */
 119         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 120             if (function_exists($function)) {
 121                 $ret = $function($parm);
 122                 if ($ret) {
 123                     $yea++;
 124                 } else {
 125                     $nay++;
 126                 }
 127             }
 128         }
 129
 130         /* Examine the aftermath and assign the return value appropriately */
 131         if (($priority > 0) && ($yea)) {
 132             $ret = true;
 133         } elseif (($priority < 0) && ($nay)) {
 134             $ret = false;
 135         } elseif ($yea > $nay) {
 136             $ret = true;
 137         } elseif ($nay > $yea) {
 138             $ret = false;
 139         } else {
 140             // There's a tie, no action needed.
 141         }
 142         return $ret;
 143     }
 144     // If the code gets here, there was a problem - no hooks, etc.
 145     return NULL;
 146 }
 147
 148 /**
 149  * This function checks whether the user's USER_AGENT is known to
 150  * be broken. If so, returns true and the plugin is invisible to the
 151  * offending browser.
 152  */
 153 function soupNazi(){
 154
 155     $soup_menu = array('Mozilla/3','Mozilla/2','Mozilla/1', 'Opera 4',
 156                        'Opera/4', 'OmniWeb', 'Lynx');
 157     sqgetGlobalVar('HTTP_USER_AGENT', $user_agent, SQ_SERVER);
 158     foreach($soup_menu as $browser) {
 159         if(stristr($user_agent, $browser)) {
 160             return 1;
 161         }
 162     }
 163     return 0;
 164 }
 165 /*************************************/
 166 /*** MAIN PLUGIN LOADING CODE HERE ***/
 167 /*************************************/
 168
 169 /* On startup, register all plugins configured for use. */
 170 if (isset($plugins) && is_array($plugins)) {
 171     foreach ($plugins as $name) {
 172         use_plugin($name);
 173     }
 174 }
 175
 176 ?>