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, $currentHookName;
  46     $data = func_get_args();
  47     $ret = '';
  48     $currentHookName = $name;
  49
  50     if (isset($squirrelmail_plugin_hooks[$name])
  51           && is_array($squirrelmail_plugin_hooks[$name])) {
  52         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  53             /* Add something to set correct gettext domain for plugin. */
  54             if (function_exists($function)) {
  55                 $function($data);
  56             }
  57         }
  58     }
  59
  60     $currentHookName = '';
  61
  62     /* Variable-length argument lists have a slight problem when */
  63     /* passing values by reference. Pity. This is a workaround.  */
  64     return $data;
  65 }
  66
  67 /**
  68  * This function executes a hook and allows for parameters to be passed.
  69  *
  70  * @param string name the name of the hook
  71  * @param mixed param the parameters to pass to the hook function
  72  * @return mixed the return value of the hook function
  73  */
  74 function do_hook_function($name,$parm=NULL) {
  75     global $squirrelmail_plugin_hooks, $currentHookName;
  76     $ret = '';
  77     $currentHookName = $name;
  78
  79     if (isset($squirrelmail_plugin_hooks[$name])
  80           && is_array($squirrelmail_plugin_hooks[$name])) {
  81         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  82             /* Add something to set correct gettext domain for plugin. */
  83             if (function_exists($function)) {
  84                 $ret = $function($parm);
  85             }
  86         }
  87     }
  88
  89     $currentHookName = '';
  90
  91     /* Variable-length argument lists have a slight problem when */
  92     /* passing values by reference. Pity. This is a workaround.  */
  93     return $ret;
  94 }
  95
  96 /**
  97  * This function executes a hook, concatenating the results of each
  98  * plugin that has the hook defined.
  99  *
 100  * @param string name the name of the hook
 101  * @param mixed parm optional hook function parameters
 102  * @return string a concatenation of the results of each plugin function
 103  */
 104 function concat_hook_function($name,$parm=NULL) {
 105     global $squirrelmail_plugin_hooks, $currentHookName;
 106     $ret = '';
 107     $currentHookName = $name;
 108
 109     if (isset($squirrelmail_plugin_hooks[$name])
 110           && is_array($squirrelmail_plugin_hooks[$name])) {
 111         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 112             /* Concatenate results from hook. */
 113             if (function_exists($function)) {
 114                 $ret .= $function($parm);
 115             }
 116         }
 117     }
 118
 119     $currentHookName = '';
 120
 121     /* Variable-length argument lists have a slight problem when */
 122     /* passing values by reference. Pity. This is a workaround.  */
 123     return $ret;
 124 }
 125
 126 /**
 127  * This function is used for hooks which are to return true or
 128  * false. If $priority is > 0, any one or more trues will override
 129  * any falses. If $priority < 0, then one or more falses will
 130  * override any trues.
 131  * Priority 0 means majority rules.  Ties will be broken with $tie
 132  *
 133  * @param string name the hook name
 134  * @param mixed parm the parameters for the hook function
 135  * @param int priority
 136  * @param bool tie
 137  * @return bool the result of the function
 138  */
 139 function boolean_hook_function($name,$parm=NULL,$priority=0,$tie=false) {
 140     global $squirrelmail_plugin_hooks, $currentHookName;
 141     $yea = 0;
 142     $nay = 0;
 143     $ret = $tie;
 144
 145     if (isset($squirrelmail_plugin_hooks[$name]) &&
 146         is_array($squirrelmail_plugin_hooks[$name])) {
 147
 148         /* Loop over the plugins that registered the hook */
 149         $currentHookName = $name;
 150         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 151             if (function_exists($function)) {
 152                 $ret = $function($parm);
 153                 if ($ret) {
 154                     $yea++;
 155                 } else {
 156                     $nay++;
 157                 }
 158             }
 159         }
 160         $currentHookName = '';
 161
 162         /* Examine the aftermath and assign the return value appropriately */
 163         if (($priority > 0) && ($yea)) {
 164             $ret = true;
 165         } elseif (($priority < 0) && ($nay)) {
 166             $ret = false;
 167         } elseif ($yea > $nay) {
 168             $ret = true;
 169         } elseif ($nay > $yea) {
 170             $ret = false;
 171         } else {
 172             // There's a tie, no action needed.
 173         }
 174         return $ret;
 175     }
 176     // If the code gets here, there was a problem - no hooks, etc.
 177     return NULL;
 178 }
 179
 180 /**
 181  * This function checks whether the user's USER_AGENT is known to
 182  * be broken. If so, returns true and the plugin is invisible to the
 183  * offending browser.
 184  * *** THIS IS A TEST FOR JAVASCRIPT SUPPORT ***
 185  * FIXME: This function needs to have its name changed!
 186  *
 187  * @return bool whether this browser properly supports JavaScript
 188  */
 189 function soupNazi(){
 190     return !checkForJavascript();
 191 }
 192 /*************************************/
 193 /*** MAIN PLUGIN LOADING CODE HERE ***/
 194 /*************************************/
 195
 196 /* On startup, register all plugins configured for use. */
 197 if (isset($plugins) && is_array($plugins)) {
 198     foreach ($plugins as $name) {
 199         use_plugin($name);
 200     }
 201 }
 202
 203 ?>