functions/plugin.php

   1 <?php
   2
   3 /**
   4  * plugin.php
   5  *
   6  * This file provides the framework for a plugin architecture.
   7  *
   8  * Documentation on how to write plugins might show up some time.
   9  *
  10  * @copyright &copy; 1999-2006 The SquirrelMail Project Team
  11  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  12  * @version $Id$
  13  * @package squirrelmail
  14  */
  15
  16 /** Everything needs global.. */
  17 require_once(SM_PATH . 'functions/global.php');
  18 require_once(SM_PATH . 'functions/prefs.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, $currentHookName;
  45     $data = func_get_args();
  46     $currentHookName = $name;
  47
  48     if (isset($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     $currentHookName = '';
  59
  60     /* Variable-length argument lists have a slight problem when */
  61     /* passing values by reference. Pity. This is a workaround.  */
  62     return $data;
  63 }
  64
  65 /**
  66  * This function executes a hook and allows for parameters to be passed.
  67  *
  68  * @param string name the name of the hook
  69  * @param mixed param the parameters to pass to the hook function
  70  * @return mixed the return value of the hook function
  71  */
  72 function do_hook_function($name,$parm=NULL) {
  73     global $squirrelmail_plugin_hooks, $currentHookName;
  74     $ret = '';
  75     $currentHookName = $name;
  76
  77     if (isset($squirrelmail_plugin_hooks[$name])
  78           && is_array($squirrelmail_plugin_hooks[$name])) {
  79         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
  80             /* Add something to set correct gettext domain for plugin. */
  81             if (function_exists($function)) {
  82                 $ret = $function($parm);
  83             }
  84         }
  85     }
  86
  87     $currentHookName = '';
  88
  89     /* Variable-length argument lists have a slight problem when */
  90     /* passing values by reference. Pity. This is a workaround.  */
  91     return $ret;
  92 }
  93
  94 /**
  95  * This function executes a hook, concatenating the results of each
  96  * plugin that has the hook defined.
  97  *
  98  * @param string name the name of the hook
  99  * @param mixed parm optional hook function parameters
 100  * @return string a concatenation of the results of each plugin function
 101  */
 102 function concat_hook_function($name,$parm=NULL) {
 103     global $squirrelmail_plugin_hooks, $currentHookName;
 104     $ret = '';
 105     $currentHookName = $name;
 106
 107     if (isset($squirrelmail_plugin_hooks[$name])
 108           && is_array($squirrelmail_plugin_hooks[$name])) {
 109         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 110             /* Concatenate results from hook. */
 111             if (function_exists($function)) {
 112                 $ret .= $function($parm);
 113             }
 114         }
 115     }
 116
 117     $currentHookName = '';
 118
 119     /* Variable-length argument lists have a slight problem when */
 120     /* passing values by reference. Pity. This is a workaround.  */
 121     return $ret;
 122 }
 123
 124 /**
 125  * This function is used for hooks which are to return true or
 126  * false. If $priority is > 0, any one or more trues will override
 127  * any falses. If $priority < 0, then one or more falses will
 128  * override any trues.
 129  * Priority 0 means majority rules.  Ties will be broken with $tie
 130  *
 131  * @param string name the hook name
 132  * @param mixed parm the parameters for the hook function
 133  * @param int priority
 134  * @param bool tie
 135  * @return bool the result of the function
 136  */
 137 function boolean_hook_function($name,$parm=NULL,$priority=0,$tie=false) {
 138     global $squirrelmail_plugin_hooks, $currentHookName;
 139     $yea = 0;
 140     $nay = 0;
 141     $ret = $tie;
 142
 143     if (isset($squirrelmail_plugin_hooks[$name]) &&
 144         is_array($squirrelmail_plugin_hooks[$name])) {
 145
 146         /* Loop over the plugins that registered the hook */
 147         $currentHookName = $name;
 148         foreach ($squirrelmail_plugin_hooks[$name] as $function) {
 149             if (function_exists($function)) {
 150                 $ret = $function($parm);
 151                 if ($ret) {
 152                     $yea++;
 153                 } else {
 154                     $nay++;
 155                 }
 156             }
 157         }
 158         $currentHookName = '';
 159
 160         /* Examine the aftermath and assign the return value appropriately */
 161         if (($priority > 0) && ($yea)) {
 162             $ret = true;
 163         } elseif (($priority < 0) && ($nay)) {
 164             $ret = false;
 165         } elseif ($yea > $nay) {
 166             $ret = true;
 167         } elseif ($nay > $yea) {
 168             $ret = false;
 169         } else {
 170             // There's a tie, no action needed.
 171         }
 172         return $ret;
 173     }
 174     // If the code gets here, there was a problem - no hooks, etc.
 175     return NULL;
 176 }
 177
 178 /**
 179  * This function checks whether the user's USER_AGENT is known to
 180  * be broken. If so, returns true and the plugin is invisible to the
 181  * offending browser.
 182  * *** THIS IS A TEST FOR JAVASCRIPT SUPPORT ***
 183  * FIXME: This function needs to have its name changed!
 184  *
 185  * @return bool whether this browser properly supports JavaScript
 186  * @deprecated use checkForJavascript() since 1.5.1
 187  */
 188 function soupNazi(){
 189     return !checkForJavascript();
 190 }
 191
 192 /**
 193  * Check if plugin is enabled
 194  * @param string $plugin_name plugin name
 195  * @since 1.5.1
 196  * @return boolean
 197  */
 198 function is_plugin_enabled($plugin_name) {
 199   global $plugins;
 200
 201   /**
 202    * check if variable is empty. if var is not set, php empty
 203    * returns true without error notice.
 204    *
 205    * then check if it is an array
 206    */
 207   if (empty($plugins) || ! is_array($plugins))
 208     return false;
 209
 210   if ( in_array($plugin_name,$plugins) ) {
 211     return true;
 212   } else {
 213     return false;
 214   }
 215 }
 216
 217 /*************************************/
 218 /*** MAIN PLUGIN LOADING CODE HERE ***/
 219 /*************************************/
 220
 221 /* On startup, register all plugins configured for use. */
 222 if (isset($plugins) && is_array($plugins)) {
 223     // turn on output buffering in order to prevent output of new lines
 224     ob_start();
 225     foreach ($plugins as $name) {
 226         use_plugin($name);
 227     }
 228     // get output and remove whitespace
 229     $output = trim(ob_get_contents());
 230     ob_end_clean();
 231     // if plugins output more than newlines and spacing, stop script execution.
 232     if (!empty($output)) {
 233         die($output);
 234     }
 235 }
 236
 237 ?>