functions/plugin.php

   1 <?php
   2
   3 /**
   4  * plugin.php
   5  *
   6  * Copyright (c) 1999-2004 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  * @version $Id$
  14  * @package squirrelmail
  15  */
  16
  17 /** Everything needs global.. */
  18 require_once(SM_PATH . 'functions/global.php');
  19 require_once(SM_PATH . 'functions/prefs.php');
  20
  21 global $squirrelmail_plugin_hooks;
  22 $squirrelmail_plugin_hooks = array();
  23
  24 /**
  25  * This function adds a plugin.
  26  * @param string $name Internal plugin name (ie. delete_move_next)
  27  * @return void
  28  */
  29 function use_plugin ($name) {
  30     if (file_exists(SM_PATH . "plugins/$name/setup.php")) {
  31         include_once(SM_PATH . "plugins/$name/setup.php");
  32         $function = "squirrelmail_plugin_init_$name";
  33         if (function_exists($function)) {
  34             $function();
  35         }
  36     }
  37 }
  38
  39 /**
  40  * This function executes a hook.
  41  * @param string $name Name of hook to fire
  42  * @return mixed $data
  43  */
  44 function do_hook ($name) {
  45     global $squirrelmail_plugin_hooks;
  46     $data = func_get_args();
  47     $ret = '';
  48
  49     if (isset($squirrelmail_plugin_hooks[$name])
  50           && is_array($squirrelmail_plugin_hooks[$name])) {
  51         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  52             /* Add something to set correct gettext domain for plugin. */
  53             if (function_exists($function)) {
  54                 $function($data);
  55             }
  56         }
  57     }
  58
  59     /* Variable-length argument lists have a slight problem when */
  60     /* passing values by reference. Pity. This is a workaround.  */
  61     return $data;
  62 }
  63
  64 /**
  65  * This function executes a hook and allows for parameters to be passed.
  66  *
  67  * @param string name the name of the hook
  68  * @param mixed param the parameters to pass to the hook function
  69  * @return mixed the return value of the hook function
  70  */
  71 function do_hook_function($name,$parm=NULL) {
  72     global $squirrelmail_plugin_hooks;
  73     $ret = '';
  74
  75     if (isset($squirrelmail_plugin_hooks[$name])
  76           && is_array($squirrelmail_plugin_hooks[$name])) {
  77         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  78             /* Add something to set correct gettext domain for plugin. */
  79             if (function_exists($function)) {
  80                 $ret = $function($parm);
  81             }
  82         }
  83     }
  84
  85     /* Variable-length argument lists have a slight problem when */
  86     /* passing values by reference. Pity. This is a workaround.  */
  87     return $ret;
  88 }
  89
  90 /**
  91  * This function executes a hook, concatenating the results of each
  92  * plugin that has the hook defined.
  93  *
  94  * @param string name the name of the hook
  95  * @param mixed parm optional hook function parameters
  96  * @return string a concatenation of the results of each plugin function
  97  */
  98 function concat_hook_function($name,$parm=NULL) {
  99     global $squirrelmail_plugin_hooks;
 100     $ret = '';
 101
 102     if (isset($squirrelmail_plugin_hooks[$name])
 103           && is_array($squirrelmail_plugin_hooks[$name])) {
 104         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 105             /* Concatenate results from hook. */
 106             if (function_exists($function)) {
 107                 $ret .= $function($parm);
 108             }
 109         }
 110     }
 111
 112     /* Variable-length argument lists have a slight problem when */
 113     /* passing values by reference. Pity. This is a workaround.  */
 114     return $ret;
 115 }
 116
 117 /**
 118  * This function is used for hooks which are to return true or
 119  * false. If $priority is > 0, any one or more trues will override
 120  * any falses. If $priority < 0, then one or more falses will
 121  * override any trues.
 122  * Priority 0 means majority rules.  Ties will be broken with $tie
 123  *
 124  * @param string name the hook name
 125  * @param mixed parm the parameters for the hook function
 126  * @param int priority
 127  * @param bool tie
 128  * @return bool the result of the function
 129  */
 130 function boolean_hook_function($name,$parm=NULL,$priority=0,$tie=false) {
 131     global $squirrelmail_plugin_hooks;
 132     $yea = 0;
 133     $nay = 0;
 134     $ret = $tie;
 135
 136     if (isset($squirrelmail_plugin_hooks[$name]) &&
 137         is_array($squirrelmail_plugin_hooks[$name])) {
 138
 139         /* Loop over the plugins that registered the hook */
 140         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 141             if (function_exists($function)) {
 142                 $ret = $function($parm);
 143                 if ($ret) {
 144                     $yea++;
 145                 } else {
 146                     $nay++;
 147                 }
 148             }
 149         }
 150
 151         /* Examine the aftermath and assign the return value appropriately */
 152         if (($priority > 0) && ($yea)) {
 153             $ret = true;
 154         } elseif (($priority < 0) && ($nay)) {
 155             $ret = false;
 156         } elseif ($yea > $nay) {
 157             $ret = true;
 158         } elseif ($nay > $yea) {
 159             $ret = false;
 160         } else {
 161             // There's a tie, no action needed.
 162         }
 163         return $ret;
 164     }
 165     // If the code gets here, there was a problem - no hooks, etc.
 166     return NULL;
 167 }
 168
 169 /**
 170  * This function checks whether the user's USER_AGENT is known to
 171  * be broken. If so, returns true and the plugin is invisible to the
 172  * offending browser.
 173  * *** THIS IS A TEST FOR JAVASCRIPT SUPPORT ***
 174  * FIXME: This function needs to have its name changed!
 175  *
 176  * @return bool whether this browser properly supports JavaScript
 177  */
 178 function soupNazi(){
 179     return !checkForJavascript();
 180 }
 181 /*************************************/
 182 /*** MAIN PLUGIN LOADING CODE HERE ***/
 183 /*************************************/
 184
 185 /* On startup, register all plugins configured for use. */
 186 if (isset($plugins) && is_array($plugins)) {
 187     foreach ($plugins as $name) {
 188         use_plugin($name);
 189     }
 190 }
 191
 192 ?>