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; 1999-2007 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 /**
  17  * This function adds a plugin.
  18  * @param string $name Internal plugin name (ie. delete_move_next)
  19  * @return void
  20  */
  21 function use_plugin ($name) {
  22     if (file_exists(SM_PATH . "plugins/$name/setup.php")) {
  23         include_once(SM_PATH . "plugins/$name/setup.php");
  24
  25         /**
  26           * As of SM 1.5.2, plugin hook registration is statically
  27           * accomplished using the configuration utility (config/conf.pl).
  28           * And this code is deprecated (but let's keep it until
  29           * the new registration system is proven).
  30           *
  31           */
  32         //$function = "squirrelmail_plugin_init_$name";
  33         //if (function_exists($function)) {
  34         //    $function();
  35         //}
  36     }
  37 }
  38
  39 /**
  40  * This function executes a plugin hook.
  41  *
  42  * It includes an arbitrary return value that is managed by
  43  * all plugins on the same hook and returned to the core hook
  44  * location.
  45  *
  46  * The desired format of the return value should be defined
  47  * by the context in which the hook is called.
  48  *
  49  * Note that the master return value for this hook is passed
  50  * to each plugin after the main argument(s) value/array as a
  51  * convenience only - to show what the current return value is
  52  * even though it is liable to be changed by other plugins.
  53  *
  54  * If any plugin on this hook wants to modify the $args
  55  * plugin parameter, it simply has to use call-by-reference
  56  * syntax in the hook function that it has registered for the
  57  * current hook.  Note that this is in addition to (entirely
  58  * independent of) the return value for this hook.
  59  *
  60  * @param string $name Name of hook being executed
  61  * @param mixed  $args A single value or an array of arguments
  62  *                     that are to be passed to all plugins
  63  *                     operating off the hook being called.
  64  *                     Note that this argument is passed by
  65  *                     reference thus it is liable to be
  66  *                     changed after the hook completes.
  67  *
  68  * @return mixed The return value that is managed by the plugins
  69  *               on the current hook.
  70  *
  71  */
  72 function do_hook($name, &$args) {
  73
  74     global $squirrelmail_plugin_hooks, $currentHookName;
  75     $currentHookName = $name;
  76     $ret = NULL;
  77
  78     if (isset($squirrelmail_plugin_hooks[$name])
  79           && is_array($squirrelmail_plugin_hooks[$name])) {
  80         foreach ($squirrelmail_plugin_hooks[$name] as $plugin_name => $function) {
  81             use_plugin($plugin_name);
  82             if (function_exists($function)) {
  83                 $ret = $function($args, $ret);
  84             }
  85         }
  86     }
  87
  88     $currentHookName = '';
  89     return $ret;
  90
  91 }
  92
  93 /**
  94  * This function executes a hook that allows for an arbitrary
  95  * return value from each plugin that will be merged into one
  96  * array (or one string if all return values are strings) and
  97  * returned to the core hook location.
  98  *
  99  * Note that unlike PHP's array_merge function, matching array keys
 100  * will not overwrite each other, instead, values under such keys
 101  * will be concatenated if they are both strings, or merged if they
 102  * are arrays (in the same (non-overwrite) manner recursively).
 103  *
 104  * Plugins returning non-arrays (strings, objects, etc) will have
 105  * their output added to the end of the ultimate return array,
 106  * unless ALL values returned are strings, in which case one string
 107  * with all returned strings concatenated together is returned
 108  * (unless $force_array is TRUE).
 109  *
 110  * If any plugin on this hook wants to modify the $args
 111  * plugin parameter, it simply has to use call-by-reference
 112  * syntax in the hook function that it has registered for the
 113  * current hook.  Note that this is in addition to (entirely
 114  * independent of) the return value for this hook.
 115  *
 116  * @param string  $name Name of hook being executed
 117  * @param mixed   $args A single value or an array of arguments
 118  *                      that are to be passed to all plugins
 119  *                      operating off the hook being called.
 120  *                      Note that this argument is passed by
 121  *                      reference thus it is liable to be
 122  *                      changed after the hook completes.
 123  * @param boolean $force_array When TRUE, guarantees the return
 124  *                             value will ALWAYS be an array,
 125  *                             (simple strings will be forced
 126  *                             into a one-element array).
 127  *                             When FALSE, behavior is as
 128  *                             described above (OPTIONAL;
 129  *                             default behavior is to return
 130  *                             mixed - array or string).
 131  *
 132  * @return mixed the merged return arrays or strings of each
 133  *               plugin on this hook.
 134  *
 135  */
 136 function concat_hook_function($name, &$args, $force_array=FALSE) {
 137
 138     global $squirrelmail_plugin_hooks, $currentHookName;
 139     $currentHookName = $name;
 140     $ret = '';
 141
 142     if (isset($squirrelmail_plugin_hooks[$name])
 143           && is_array($squirrelmail_plugin_hooks[$name])) {
 144         foreach ($squirrelmail_plugin_hooks[$name] as $plugin_name => $function) {
 145             use_plugin($plugin_name);
 146             if (function_exists($function)) {
 147                 $plugin_ret = $function($args);
 148                 if (!empty($plugin_ret)) {
 149                     $ret = sqm_array_merge($ret, $plugin_ret);
 150                 }
 151             }
 152         }
 153     }
 154
 155     if ($force_array && is_string($ret)) {
 156         $ret = array($ret);
 157     }
 158
 159     $currentHookName = '';
 160     return $ret;
 161
 162 }
 163
 164 /**
 165  * This function is used for hooks which are to return true or
 166  * false. If $priority is > 0, any one or more trues will override
 167  * any falses. If $priority < 0, then one or more falses will
 168  * override any trues.
 169  * Priority 0 means majority rules.  Ties will be broken with $tie
 170  *
 171  * If any plugin on this hook wants to modify the $args
 172  * plugin parameter, it simply has to use call-by-reference
 173  * syntax in the hook function that it has registered for the
 174  * current hook.  Note that this is in addition to (entirely
 175  * independent of) the return value for this hook.
 176  *
 177  * @param string  $name     The hook name
 178  * @param mixed   $args     A single value or an array of arguments
 179  *                          that are to be passed to all plugins
 180  *                          operating off the hook being called.
 181  *                          Note that this argument is passed by
 182  *                          reference thus it is liable to be
 183  *                          changed after the hook completes.
 184  * @param int     $priority See explanation above
 185  * @param boolean $tie      See explanation above
 186  *
 187  * @return boolean The result of the function
 188  *
 189  */
 190 function boolean_hook_function($name, &$args, $priority=0, $tie=false) {
 191
 192     global $squirrelmail_plugin_hooks, $currentHookName;
 193     $yea = 0;
 194     $nay = 0;
 195     $ret = $tie;
 196
 197     if (isset($squirrelmail_plugin_hooks[$name]) &&
 198         is_array($squirrelmail_plugin_hooks[$name])) {
 199
 200         /* Loop over the plugins that registered the hook */
 201         $currentHookName = $name;
 202         foreach ($squirrelmail_plugin_hooks[$name] as $plugin_name => $function) {
 203             use_plugin($plugin_name);
 204             if (function_exists($function)) {
 205                 $ret = $function($args);
 206                 if ($ret) {
 207                     $yea++;
 208                 } else {
 209                     $nay++;
 210                 }
 211             }
 212         }
 213         $currentHookName = '';
 214
 215         /* Examine the aftermath and assign the return value appropriately */
 216         if (($priority > 0) && ($yea)) {
 217             $ret = true;
 218         } elseif (($priority < 0) && ($nay)) {
 219             $ret = false;
 220         } elseif ($yea > $nay) {
 221             $ret = true;
 222         } elseif ($nay > $yea) {
 223             $ret = false;
 224         } else {
 225             // There's a tie, no action needed.
 226         }
 227         return $ret;
 228     }
 229     // If the code gets here, there was a problem - no hooks, etc.
 230     return NULL;
 231
 232 }
 233
 234 /**
 235  * Do not use, use checkForJavascript() instead.
 236  *
 237  * This function checks whether the user's USER_AGENT is known to
 238  * be broken. If so, returns true and the plugin is invisible to the
 239  * offending browser.
 240  * *** THIS IS A TEST FOR JAVASCRIPT SUPPORT ***
 241  *
 242  * @return bool whether this browser properly supports JavaScript
 243  * @deprecated use checkForJavascript() since 1.5.1
 244  */
 245 function soupNazi(){
 246     return !checkForJavascript();
 247 }
 248
 249 /**
 250  * Check if plugin is enabled
 251  * @param string $plugin_name plugin name
 252  * @since 1.5.1
 253  * @return boolean
 254  */
 255 function is_plugin_enabled($plugin_name) {
 256   global $plugins;
 257
 258   /**
 259    * check if variable is empty. if var is not set, php empty
 260    * returns true without error notice.
 261    *
 262    * then check if it is an array
 263    */
 264   if (empty($plugins) || ! is_array($plugins))
 265     return false;
 266
 267   if ( in_array($plugin_name,$plugins) ) {
 268     return true;
 269   } else {
 270     return false;
 271   }
 272 }
 273
 274 /**
 275   * Check a plugin's version.
 276   *
 277   * Returns TRUE if the given plugin is installed,
 278   * activated and is at minimum version $a.$b.$c.
 279   * If any one of those conditions fails, FALSE
 280   * will be returned (careful of plugins that are
 281   * sufficiently versioned but are not activated).
 282   *
 283   * By overriding the default value of $force_inclusion,
 284   * this function will attempt to grab versioning
 285   * information from the given plugin even if it
 286   * is not activated (plugin still has to be
 287   * unpackaged and set in place in the plugins
 288   * directory).  Use with care - some plugins
 289   * might break SquirrelMail when this is used.
 290   *
 291   * Note that this function assumes plugin
 292   * versioning is consistently applied in the same
 293   * fashion that SquirrelMail versions are, with the
 294   * exception that an applicable SquirrelMail
 295   * version may be appended to the version number
 296   * (which will be ignored herein).  That is, plugin
 297   * version number schemes are expected in the following
 298   * format:  1.2.3, or 1.2.3-1.4.0.
 299   *
 300   * Any characters after the third number are discarded,
 301   * so formats such as the following will also work,
 302   * although extra information about beta versions can
 303   * possibly confuse the desired results of the version
 304   * check:  1.2.3-beta4, 1.2.3.RC2, and so forth.
 305   *
 306   * @since 1.5.2
 307   *
 308   * @param string plugin_name   name of the plugin to
 309   *                             check; must precisely
 310   *                             match the plugin
 311   *                             directory name
 312   * @param int  a               major version number
 313   * @param int  b               minor version number
 314   * @param int  c               release number
 315   * @param bool force_inclusion try to get version info
 316   *                             for plugins not activated?
 317   *                             (default FALSE)
 318   *
 319   * @return bool
 320   *
 321   */
 322 function check_plugin_version($plugin_name,
 323                               $a = 0, $b = 0, $c = 0,
 324                               $force_inclusion = FALSE)
 325 {
 326
 327    $info_function = $plugin_name . '_info';
 328    $version_function = $plugin_name . '_version';
 329    $plugin_info = array();
 330    $plugin_version = FALSE;
 331
 332
 333    // first attempt to find the plugin info function, wherein
 334    // the plugin version should be available
 335    //
 336    if (function_exists($info_function))
 337       $plugin_info = $info_function();
 338    else if ($force_inclusion
 339     && file_exists(SM_PATH . 'plugins/' . $plugin_name . '/setup.php'))
 340    {
 341       include_once(SM_PATH . 'plugins/' . $plugin_name . '/setup.php');
 342       if (function_exists($info_function))
 343          $plugin_info = $info_function();
 344    }
 345    if (!empty($plugin_info['version']))
 346       $plugin_version = $plugin_info['version'];
 347
 348
 349    // otherwise, look for older version function
 350    //
 351    if (!$plugin_version && function_exists($version_function))
 352          $plugin_version = $version_function();
 353
 354
 355    if (!$plugin_version) return FALSE;
 356
 357
 358    // now massage version number into something we understand
 359    //
 360    $plugin_version = trim(preg_replace(array('/[^0-9.]+.*$/', '/[^0-9.]/'),
 361                                        '', $plugin_version),
 362                           '.');
 363    $plugin_version = explode('.', $plugin_version);
 364    if (!isset($plugin_version[0])) $plugin_version[0] = 0;
 365    if (!isset($plugin_version[1])) $plugin_version[1] = 0;
 366    if (!isset($plugin_version[2])) $plugin_version[2] = 0;
 367 //   sm_print_r($plugin_version);
 368
 369
 370    // now test the version number
 371    //
 372    if ($plugin_version[0] < $a ||
 373       ($plugin_version[0] == $a && $plugin_version[1] < $b) ||
 374       ($plugin_version[0] == $a && $plugin_version[1] == $b && $plugin_version[2] < $c))
 375          return FALSE;
 376
 377
 378    return TRUE;
 379
 380 }
 381