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                 // each plugin can call additional hooks, so need
  86                 // to make sure the current hook name is accurate
  87                 // again after each plugin has finished
  88                 //
  89                 $currentHookName = $name;
  90             }
  91         }
  92     }
  93
  94     $currentHookName = '';
  95     return $ret;
  96
  97 }
  98
  99 /**
 100  * This function executes a hook that allows for an arbitrary
 101  * return value from each plugin that will be merged into one
 102  * array (or one string if all return values are strings) and
 103  * returned to the core hook location.
 104  *
 105  * Note that unlike PHP's array_merge function, matching array keys
 106  * will not overwrite each other, instead, values under such keys
 107  * will be concatenated if they are both strings, or merged if they
 108  * are arrays (in the same (non-overwrite) manner recursively).
 109  *
 110  * Plugins returning non-arrays (strings, objects, etc) will have
 111  * their output added to the end of the ultimate return array,
 112  * unless ALL values returned are strings, in which case one string
 113  * with all returned strings concatenated together is returned
 114  * (unless $force_array is TRUE).
 115  *
 116  * If any plugin on this hook wants to modify the $args
 117  * plugin parameter, it simply has to use call-by-reference
 118  * syntax in the hook function that it has registered for the
 119  * current hook.  Note that this is in addition to (entirely
 120  * independent of) the return value for this hook.
 121  *
 122  * @param string  $name Name of hook being executed
 123  * @param mixed   $args A single value or an array of arguments
 124  *                      that are to be passed to all plugins
 125  *                      operating off the hook being called.
 126  *                      Note that this argument is passed by
 127  *                      reference thus it is liable to be
 128  *                      changed after the hook completes.
 129  * @param boolean $force_array When TRUE, guarantees the return
 130  *                             value will ALWAYS be an array,
 131  *                             (simple strings will be forced
 132  *                             into a one-element array).
 133  *                             When FALSE, behavior is as
 134  *                             described above (OPTIONAL;
 135  *                             default behavior is to return
 136  *                             mixed - array or string).
 137  *
 138  * @return mixed the merged return arrays or strings of each
 139  *               plugin on this hook.
 140  *
 141  */
 142 function concat_hook_function($name, &$args, $force_array=FALSE) {
 143
 144     global $squirrelmail_plugin_hooks, $currentHookName;
 145     $currentHookName = $name;
 146     $ret = '';
 147
 148     if (isset($squirrelmail_plugin_hooks[$name])
 149           && is_array($squirrelmail_plugin_hooks[$name])) {
 150         foreach ($squirrelmail_plugin_hooks[$name] as $plugin_name => $function) {
 151             use_plugin($plugin_name);
 152             if (function_exists($function)) {
 153                 $plugin_ret = $function($args);
 154                 if (!empty($plugin_ret)) {
 155                     $ret = sqm_array_merge($ret, $plugin_ret);
 156                 }
 157
 158                 // each plugin can call additional hooks, so need
 159                 // to make sure the current hook name is accurate
 160                 // again after each plugin has finished
 161                 //
 162                 $currentHookName = $name;
 163             }
 164         }
 165     }
 166
 167     if ($force_array && is_string($ret)) {
 168         $ret = array($ret);
 169     }
 170
 171     $currentHookName = '';
 172     return $ret;
 173
 174 }
 175
 176 /**
 177  * This function is used for hooks which are to return true or
 178  * false. If $priority is > 0, any one or more trues will override
 179  * any falses. If $priority < 0, then one or more falses will
 180  * override any trues.
 181  * Priority 0 means majority rules.  Ties will be broken with $tie
 182  *
 183  * If any plugin on this hook wants to modify the $args
 184  * plugin parameter, it simply has to use call-by-reference
 185  * syntax in the hook function that it has registered for the
 186  * current hook.  Note that this is in addition to (entirely
 187  * independent of) the return value for this hook.
 188  *
 189  * @param string  $name     The hook name
 190  * @param mixed   $args     A single value or an array of arguments
 191  *                          that are to be passed to all plugins
 192  *                          operating off the hook being called.
 193  *                          Note that this argument is passed by
 194  *                          reference thus it is liable to be
 195  *                          changed after the hook completes.
 196  * @param int     $priority See explanation above
 197  * @param boolean $tie      See explanation above
 198  *
 199  * @return boolean The result of the function
 200  *
 201  */
 202 function boolean_hook_function($name, &$args, $priority=0, $tie=false) {
 203
 204     global $squirrelmail_plugin_hooks, $currentHookName;
 205     $yea = 0;
 206     $nay = 0;
 207     $ret = $tie;
 208
 209     if (isset($squirrelmail_plugin_hooks[$name]) &&
 210         is_array($squirrelmail_plugin_hooks[$name])) {
 211
 212         /* Loop over the plugins that registered the hook */
 213         $currentHookName = $name;
 214         foreach ($squirrelmail_plugin_hooks[$name] as $plugin_name => $function) {
 215             use_plugin($plugin_name);
 216             if (function_exists($function)) {
 217                 $ret = $function($args);
 218                 if ($ret) {
 219                     $yea++;
 220                 } else {
 221                     $nay++;
 222                 }
 223
 224                 // each plugin can call additional hooks, so need
 225                 // to make sure the current hook name is accurate
 226                 // again after each plugin has finished
 227                 //
 228                 $currentHookName = $name;
 229             }
 230         }
 231         $currentHookName = '';
 232
 233         /* Examine the aftermath and assign the return value appropriately */
 234         if (($priority > 0) && ($yea)) {
 235             $ret = true;
 236         } elseif (($priority < 0) && ($nay)) {
 237             $ret = false;
 238         } elseif ($yea > $nay) {
 239             $ret = true;
 240         } elseif ($nay > $yea) {
 241             $ret = false;
 242         } else {
 243             // There's a tie, no action needed.
 244         }
 245         return $ret;
 246     }
 247     // If the code gets here, there was a problem - no hooks, etc.
 248     return NULL;
 249
 250 }
 251
 252 /**
 253  * Do not use, use checkForJavascript() instead.
 254  *
 255  * This function checks whether the user's USER_AGENT is known to
 256  * be broken. If so, returns true and the plugin is invisible to the
 257  * offending browser.
 258  * *** THIS IS A TEST FOR JAVASCRIPT SUPPORT ***
 259  *
 260  * @return bool whether this browser properly supports JavaScript
 261  * @deprecated use checkForJavascript() since 1.5.1
 262  */
 263 function soupNazi(){
 264     return !checkForJavascript();
 265 }
 266
 267 /**
 268  * Check if plugin is enabled
 269  * @param string $plugin_name plugin name
 270  * @since 1.5.1
 271  * @return boolean
 272  */
 273 function is_plugin_enabled($plugin_name) {
 274   global $plugins;
 275
 276   /**
 277    * check if variable is empty. if var is not set, php empty
 278    * returns true without error notice.
 279    *
 280    * then check if it is an array
 281    */
 282   if (empty($plugins) || ! is_array($plugins))
 283     return false;
 284
 285   if ( in_array($plugin_name,$plugins) ) {
 286     return true;
 287   } else {
 288     return false;
 289   }
 290 }
 291
 292 /**
 293   * Get a plugin's version.
 294   *
 295   * Determines and returns a plugin's version.
 296   *
 297   * By default, the desired plugin must be currently
 298   * activated, and if it is not, this function will
 299   * return FALSE.  By overriding the default value
 300   * of $force_inclusion, this function will attempt
 301   * to grab versioning information from the given
 302   * plugin even if it is not activated (plugin still
 303   * has to be unpackaged and set in place in the
 304   * plugins directory).  Use with care - some plugins
 305   * might break SquirrelMail when this is used.
 306   *
 307   * By turning on the $do_parse argument, the version
 308   * string will be parsed by SquirrelMail into a
 309   * SquirrelMail-compatible version string (such as
 310   * "1.2.3") if it is not already.
 311   *
 312   * Note that this assumes plugin versioning is
 313   * consistently applied in the same fashion that
 314   * SquirrelMail versions are, with the exception that
 315   * an applicable SquirrelMail version may be appended
 316   * to the version number (which will be ignored herein).
 317   * That is, plugin version number schemes are expected
 318   * in the following format:  1.2.3, or 1.2.3-1.4.0.
 319   *
 320   * Any characters after the third version number
 321   * indicating things such as beta or release candidate
 322   * versions are discarded, so formats such as the
 323   * following will also work, although extra information
 324   * about beta versions can possibly confuse the desired
 325   * results of the version check:  1.2.3-beta4, 1.2.3.RC2,
 326   * and so forth.
 327   *
 328   * @since 1.5.2
 329   *
 330   * @param string plugin_name   name of the plugin to
 331   *                             check; must precisely
 332   *                             match the plugin
 333   *                             directory name
 334   * @param bool force_inclusion try to get version info
 335   *                             for plugins not activated?
 336   *                             (default FALSE)
 337   * @param bool do_parse        return the plugin version
 338   *                             in SquirrelMail-compatible
 339   *                             format (default FALSE)
 340   *
 341   * @return mixed The plugin version string if found, otherwise,
 342   *               boolean FALSE is returned indicating that no
 343   *               version information could be found for the plugin.
 344   *
 345   */
 346 function get_plugin_version($plugin_name, $force_inclusion = FALSE, $do_parse = FALSE)
 347 {
 348
 349    $info_function = $plugin_name . '_info';
 350    $version_function = $plugin_name . '_version';
 351    $plugin_info = array();
 352    $plugin_version = FALSE;
 353
 354
 355    // first attempt to find the plugin info function, wherein
 356    // the plugin version should be available
 357    //
 358    if (function_exists($info_function))
 359       $plugin_info = $info_function();
 360    else if ($force_inclusion
 361     && file_exists(SM_PATH . 'plugins/' . $plugin_name . '/setup.php'))
 362    {
 363
 364       /* --- Old code, keeping just in case... problem with it is, for example,
 365          if it is used, but later we are checking if the same plugin is
 366          activated (because it SHOULD be), this code having run will possibly
 367          create a false positive.
 368       include_once(SM_PATH . 'plugins/' . $plugin_name . '/setup.php');
 369       if (function_exists($info_function))
 370          $plugin_info = $info_function();
 371       --- */
 372
 373       // so what we need to do is process this plugin without
 374       // it polluting our environment
 375       //
 376       // we *could* just use the above code, which is more of a
 377       // sure thing than some regular expressions, and then test
 378       // the contents of the $plugins array to see if this plugin
 379       // is actually activated, and that might be good enough, but
 380       // for now, we'll use the following approach, because of two
 381       // concerns: other plugins and other templates might force
 382       // the inclusion of a plugin (which SHOULD also add it to
 383       // the $plugins array, but am not 100% sure at this time (FIXME)),
 384       // and because the regexps below should work just fine with
 385       // any resonably formatted plugin setup file.
 386       //
 387       // read the target plugin's setup.php file into a string,
 388       // then use a regular expression to try to find the version...
 389       // this of course can break if plugin authors do funny things
 390       // with their file formatting
 391       //
 392       $setup_file = '';
 393       $file_contents = file(SM_PATH . 'plugins/' . $plugin_name . '/setup.php');
 394       foreach ($file_contents as $line)
 395          $setup_file .= $line;
 396
 397
 398       // this regexp grabs a version number from a standard
 399       // <plugin>_info() function
 400       //
 401       if (preg_match('/[\'"]version[\'"]\s*=>\s*[\'"](.+?)[\'"]/is', $setup_file, $matches))
 402          $plugin_info = array('version' => $matches[1]);
 403
 404
 405       // this regexp grabs a version number from a standard
 406       // (deprecated) <plugin>_version() function
 407       //
 408       else if (preg_match('/function\s+.*?' . $plugin_name . '_version.*?\(.*?\).*?\{.*?return\s+[\'"](.+?)[\'"]/is', $setup_file, $matches))
 409          $plugin_info = array('version' => $matches[1]);
 410
 411    }
 412    if (!empty($plugin_info['version']))
 413       $plugin_version = $plugin_info['version'];
 414
 415
 416    // otherwise, look for older version function
 417    //
 418    if (!$plugin_version && function_exists($version_function))
 419        $plugin_version = $version_function();
 420
 421
 422    if ($plugin_version && $do_parse)
 423    {
 424
 425       // massage version number into something we understand
 426       //
 427       // the first regexp strips everything and anything that follows
 428       // the first occurance of a non-digit (or non decimal point), so
 429       // beware that putting letters in the middle of a version string
 430       // will effectively truncate the version string right there (but
 431       // this also just helps remove the SquirrelMail version part off
 432       // of versions such as "1.2.3-1.4.4")
 433       //
 434       // the second regexp just strips out non-digits/non-decimal points
 435       // (and might be redundant(?))
 436       //
 437       // the regexps are wrapped in a trim that makes sure the version
 438       // does not start or end with a decimal point
 439       //
 440       $plugin_version = trim(preg_replace(array('/[^0-9.]+.*$/', '/[^0-9.]/'),
 441                                           '', $plugin_version),
 442                              '.');
 443
 444    }
 445
 446    return $plugin_version;
 447
 448 }
 449
 450 /**
 451   * Check a plugin's version.
 452   *
 453   * Returns TRUE if the given plugin is installed,
 454   * activated and is at minimum version $a.$b.$c.
 455   * If any one of those conditions fails, FALSE
 456   * will be returned (careful of plugins that are
 457   * sufficiently versioned but are not activated).
 458   *
 459   * By overriding the default value of $force_inclusion,
 460   * this function will attempt to grab versioning
 461   * information from the given plugin even if it
 462   * is not activated (the plugin still has to be
 463   * unpackaged and set in place in the plugins
 464   * directory).  Use with care - some plugins
 465   * might break SquirrelMail when this is used.
 466   *
 467   * Note that this function assumes plugin
 468   * versioning is consistently applied in the same
 469   * fashion that SquirrelMail versions are, with the
 470   * exception that an applicable SquirrelMail
 471   * version may be appended to the version number
 472   * (which will be ignored herein).  That is, plugin
 473   * version number schemes are expected in the following
 474   * format:  1.2.3, or 1.2.3-1.4.0.
 475   *
 476   * Any characters after the third number indicating
 477   * things such as beta or release candidate versions
 478   * are discarded, so formats such as the following
 479   * will also work, although extra information about
 480   * beta versions can possibly confuse the desired results
 481   * of the version check:  1.2.3-beta4, 1.2.3.RC2, and so forth.
 482   *
 483   * @since 1.5.2
 484   *
 485   * @param string plugin_name   Name of the plugin to
 486   *                             check; must precisely
 487   *                             match the plugin
 488   *                             directory name
 489   * @param int  a               Major version number
 490   * @param int  b               Minor version number
 491   * @param int  c               Release number
 492   * @param bool force_inclusion Try to get version info
 493   *                             for plugins not activated?
 494   *                             (default FALSE)
 495   *
 496   * @return bool
 497   *
 498   */
 499 function check_plugin_version($plugin_name,
 500                               $a = 0, $b = 0, $c = 0,
 501                               $force_inclusion = FALSE)
 502 {
 503
 504    $plugin_version = get_plugin_version($plugin_name, $force_inclusion, TRUE);
 505    if (!$plugin_version) return FALSE;
 506
 507
 508    // split the version string into sections delimited by
 509    // decimal points, and make sure we have three sections
 510    //
 511    $plugin_version = explode('.', $plugin_version);
 512    if (!isset($plugin_version[0])) $plugin_version[0] = 0;
 513    if (!isset($plugin_version[1])) $plugin_version[1] = 0;
 514    if (!isset($plugin_version[2])) $plugin_version[2] = 0;
 515 //   sm_print_r($plugin_version);
 516
 517
 518    // now test the version number
 519    //
 520    if ($plugin_version[0] < $a ||
 521       ($plugin_version[0] == $a && $plugin_version[1] < $b) ||
 522       ($plugin_version[0] == $a && $plugin_version[1] == $b && $plugin_version[2] < $c))
 523          return FALSE;
 524
 525
 526    return TRUE;
 527
 528 }
 529
 530 /**
 531   * Get a certain plugin requirement.
 532   *
 533   * Attempts to find the given plugin requirement value
 534   * in the given plugin's informational array, and returns
 535   * it or NULL if it was not found.
 536   *
 537   * Some plugins have different values for the same
 538   * requirement depending on the SquirrelMail version,
 539   * and this function is smart enough to take that into
 540   * account.
 541   *
 542   * By default, the desired plugin must be currently
 543   * activated, and if it is not, this function will
 544   * return NULL.  By overriding the default value
 545   * of $force_inclusion, this function will attempt
 546   * to grab requirement information from the given
 547   * plugin even if it is not activated (plugin still
 548   * has to be unpackaged and set in place in the
 549   * plugins directory).  Use with care - some plugins
 550   * might break SquirrelMail when this is used.
 551   *
 552   * @since 1.5.2
 553   *
 554   * @param string plugin_name   Name of the plugin to
 555   *                             check; must precisely
 556   *                             match the plugin
 557   *                             directory name
 558   * @param string requirement   The desired requirement name
 559   * @param bool force_inclusion Try to get requirement info
 560   *                             for plugins not activated?
 561   *                             (default FALSE)
 562   *
 563   * @return mixed NULL is returned if the plugin could not be
 564   *               found or does not include the given requirement,
 565   *               otherwise the value of the requirement is returned,
 566   *               whatever that may be (varies per requirement type).
 567   *
 568   */
 569 function get_plugin_requirement($plugin_name, $requirement,
 570                                 $force_inclusion = FALSE)
 571 {
 572
 573    $info_function = $plugin_name . '_info';
 574    $plugin_info = array();
 575    $requirement_value = NULL;
 576
 577
 578    // first attempt to find the plugin info function, wherein
 579    // the plugin requirements should be available
 580    //
 581    if (function_exists($info_function))
 582       $plugin_info = $info_function();
 583    else if ($force_inclusion
 584     && file_exists(SM_PATH . 'plugins/' . $plugin_name . '/setup.php'))
 585    {
 586
 587       /* --- Old code, keeping just in case... problem with it is, for example,
 588          if it is used, but later we are checking if the same plugin is
 589          activated (because it SHOULD be), this code having run will possibly
 590          create a false positive.
 591       include_once(SM_PATH . 'plugins/' . $plugin_name . '/setup.php');
 592       if (function_exists($info_function))
 593          $plugin_info = $info_function();
 594       --- */
 595
 596       // so what we need to do is process this plugin without
 597       // it polluting our environment
 598       //
 599       // we *could* just use the above code, which is more of a
 600       // sure thing than a regular expression, and then test
 601       // the contents of the $plugins array to see if this plugin
 602       // is actually activated, and that might be good enough, but
 603       // for now, we'll use the following approach, because of two
 604       // concerns: other plugins and other templates might force
 605       // the inclusion of a plugin (which SHOULD also add it to
 606       // the $plugins array, but am not 100% sure at this time (FIXME)),
 607       // and because the regexp below should work just fine with
 608       // any resonably formatted plugin setup file.
 609       //
 610       // read the target plugin's setup.php file into a string,
 611       // then use a regular expression to try to find the needed
 612       // requirement information...
 613       // this of course can break if plugin authors do funny things
 614       // with their file formatting
 615       //
 616       $setup_file = '';
 617       $file_contents = file(SM_PATH . 'plugins/' . $plugin_name . '/setup.php');
 618       foreach ($file_contents as $line)
 619          $setup_file .= $line;
 620
 621
 622       // this regexp grabs the full plugin info array from a standard
 623       // <plugin>_info() function... determining the end of the info
 624       // array can fail, but if authors end the array with ");\n"
 625       // (without quotes), then it should work well, especially because
 626       // newlines shouldn't be found inside the array after any ");"
 627       // (without quotes)
 628       //
 629       if (preg_match('/function\s+.*?' . $plugin_name . '_info.*?\(.*?\).*?\{.*?(array.+?\)\s*;)\s*' . "\n" . '/is', $setup_file, $matches))
 630          eval('$plugin_info = ' . $matches[1]);
 631
 632    }
 633
 634
 635    // attempt to get the requirement from the "global" scope
 636    // of the plugin information array
 637    //
 638    if (isset($plugin_info[$requirement])
 639     && !is_null($plugin_info[$requirement]))
 640       $requirement_value = $plugin_info[$requirement];
 641
 642
 643    // now, if there is a series of per-version requirements,
 644    // check there too
 645    //
 646    if (!empty($plugin_info['per_version_requirements'])
 647     && is_array($plugin_info['per_version_requirements']))
 648    {
 649
 650       // iterate through requirements, where keys are version
 651       // numbers -- tricky part is knowing the difference between
 652       // more than one version for which the current SM installation
 653       // passes the check_sm_version() test... we want the highest one
 654       //
 655       $requirement_value_override = NULL;
 656       $highest_version_array = array();
 657       foreach ($plugin_info['per_version_requirements'] as $version => $requirement_overrides)
 658       {
 659
 660           $version_array = explode('.', $version);
 661           if (sizeof($version_array) != 3) continue;
 662
 663           $a = $version_array[0];
 664           $b = $version_array[1];
 665           $c = $version_array[2];
 666
 667           if (check_sm_version($a, $b, $c)
 668            && isset($requirement_overrides[$requirement])
 669            && !is_null($requirement_overrides[$requirement]))
 670           {
 671
 672              if (empty($highest_version_array)
 673               || $highest_version_array[0] < $a
 674               || ($highest_version_array[0] == $a
 675               && $highest_version_array[1] < $b)
 676               || ($highest_version_array[0] == $a
 677               && $highest_version_array[1] == $b
 678               && $highest_version_array[2] < $c))
 679              {
 680                 $highest_version_array = $version_array;
 681                 $requirement_value_override = $requirement_overrides[$requirement];
 682              }
 683
 684          }
 685
 686       }
 687
 688       // now grab override if one is available
 689       //
 690       if (!is_null($requirement_value_override))
 691          $requirement_value = $requirement_value_override;
 692
 693    }
 694
 695    return $requirement_value;
 696
 697 }
 698
 699 /**
 700   * Get a plugin's other plugin dependencies.
 701   *
 702   * Determines and returns all the other plugins
 703   * that a given plugin requires, as well as the
 704   * minimum version numbers of the required plugins
 705   * and whether or not they need to be activated.
 706   *
 707   * By default, the desired plugin must be currently
 708   * activated, and if it is not, this function will
 709   * return FALSE.  By overriding the default value
 710   * of $force_inclusion, this function will attempt
 711   * to grab dependency information from the given
 712   * plugin even if it is not activated (plugin still
 713   * has to be unpackaged and set in place in the
 714   * plugins directory).  Use with care - some plugins
 715   * might break SquirrelMail when this is used.
 716   *
 717   * By turning on the $do_parse argument (it is on by
 718   * default), the version string for each required
 719   * plugin will be parsed by SquirrelMail into a
 720   * SquirrelMail-compatible version string (such as
 721   * "1.2.3") if it is not already.  See notes about
 722   * version formatting under the get_plugin_version()
 723   * function documentation.
 724   *
 725   * @since 1.5.2
 726   *
 727   * @param string plugin_name   name of the plugin to
 728   *                             check; must precisely
 729   *                             match the plugin
 730   *                             directory name
 731   * @param bool force_inclusion try to get version info
 732   *                             for plugins not activated?
 733   *                             (default FALSE)
 734   * @param bool do_parse        return the version numbers
 735   *                             for required plugins in
 736   *                             SquirrelMail-compatible
 737   *                             format (default FALSE)
 738   *
 739   * @return mixed Boolean FALSE is returned if the plugin
 740   *               could not be found or does not indicate
 741   *               whether it has other plugin dependencies,
 742   *               otherwise an array is returned where keys
 743   *               are the names of required plugin dependencies,
 744   *               and values are arrays again, where at least
 745   *               the following keys (and corresponding values)
 746   *               will be available: 'version' - value is the
 747   *               minimum version required for that plugin (the
 748   *               format of which might vary per the value of
 749   *               $do_parse), 'activate' - value is boolean:
 750   *               TRUE indicates that the plugin must also be
 751   *               activated, FALSE means that it only needs to
 752   *               be present, but does not need to be activated.
 753   *               Note that the return value might be an empty
 754   *               array, indicating that the plugin has no
 755   *               dependencies.
 756   *
 757   */
 758 function get_plugin_dependencies($plugin_name, $force_inclusion = FALSE,
 759                                  $do_parse = TRUE)
 760 {
 761
 762    $plugin_dependencies = get_plugin_requirement($plugin_name,
 763                                                  'required_plugins',
 764                                                  $force_inclusion);
 765
 766
 767    // not an array of requirements?  wrong format, just return FALSE
 768    //
 769    if (!is_array($plugin_dependencies))
 770       return FALSE;
 771
 772
 773    // make sure everything is in order...
 774    //
 775    if (!empty($plugin_dependencies))
 776    {
 777
 778       $new_plugin_dependencies = array();
 779       foreach ($plugin_dependencies as $plugin_name => $plugin_requirements)
 780       {
 781
 782          // if $plugin_requirements isn't an array, this is old-style,
 783          // where only the version number was given...
 784          //
 785          if (is_string($plugin_requirements))
 786             $plugin_requirements = array('version' => $plugin_requirements,
 787                                          'activate' => FALSE);
 788
 789
 790          // trap badly formatted requirements arrays that don't have
 791          // needed info
 792          //
 793          if (!is_array($plugin_requirements)
 794           || !isset($plugin_requirements['version']))
 795             continue;
 796          if (!isset($plugin_requirements['activate']))
 797             $plugin_requirements['activate'] = FALSE;
 798
 799
 800          // parse version into something we understand?
 801          //
 802          if ($do_parse)
 803          {
 804
 805             // massage version number into something we understand
 806             //
 807             // the first regexp strips everything and anything that follows
 808             // the first occurance of a non-digit (or non decimal point), so
 809             // beware that putting letters in the middle of a version string
 810             // will effectively truncate the version string right there (but
 811             // this also just helps remove the SquirrelMail version part off
 812             // of versions such as "1.2.3-1.4.4")
 813             //
 814             // the second regexp just strips out non-digits/non-decimal points
 815             // (and might be redundant(?))
 816             //
 817             // the regexps are wrapped in a trim that makes sure the version
 818             // does not start or end with a decimal point
 819             //
 820             $plugin_requirements['version']
 821                = trim(preg_replace(array('/[^0-9.]+.*$/', '/[^0-9.]/'),
 822                                    '', $plugin_requirements['version']),
 823                                    '.');
 824
 825          }
 826
 827          $new_plugin_dependencies[$plugin_name] = $plugin_requirements;
 828
 829       }
 830
 831       $plugin_dependencies = $new_plugin_dependencies;
 832
 833    }
 834
 835    return $plugin_dependencies;
 836
 837 }
 838
 839 /**
 840   * Check a plugin's other plugin dependencies.
 841   *
 842   * Determines whether or not all of the given
 843   * plugin's required plugins are installed and
 844   * up to the proper version, and if they are
 845   * activated if required.
 846   *
 847   * By default, the desired plugin must be currently
 848   * activated, and if it is not, this function will
 849   * return FALSE.  By overriding the default value
 850   * of $force_inclusion, this function will attempt
 851   * to grab dependency information from the given
 852   * plugin even if it is not activated (plugin still
 853   * has to be unpackaged and set in place in the
 854   * plugins directory).  Use with care - some plugins
 855   * might break SquirrelMail when this is used.
 856   *
 857   * NOTE that if a plugin does not report whether or
 858   * not it has other plugin dependencies, this function
 859   * will return TRUE, although that is possibly incorrect
 860   * or misleading.
 861   *
 862   * @since 1.5.2
 863   *
 864   * @param string plugin_name   name of the plugin to
 865   *                             check; must precisely
 866   *                             match the plugin
 867   *                             directory name
 868   * @param bool force_inclusion try to get version info
 869   *                             for plugins not activated?
 870   *                             (default FALSE)
 871   *
 872   * @return mixed Boolean TRUE if all of the plugin's
 873   *               required plugins are correctly installed,
 874   *               otherwise an array of the required plugins
 875   *               that are either not installed or not up to
 876   *               the minimum required version.  The array is
 877   *               keyed by plugin name where values are arrays
 878   *               again, where at least the following keys (and
 879   *               corresponding values) will be available:
 880   *               'version' - value is the minimum version
 881   *               required for that plugin (in printable, non-
 882   *               parsed format), 'activate' - value is boolean:
 883   *               TRUE indicates that the plugin must also be
 884   *               activated, FALSE means that it only needs to
 885   *               be present, but does not need to be activated.
 886   *
 887   */
 888 function check_plugin_dependencies($plugin_name, $force_inclusion = FALSE)
 889 {
 890
 891    $dependencies = get_plugin_dependencies($plugin_name, $force_inclusion);
 892    if (!$dependencies) return TRUE;
 893    $missing_or_bad = array();
 894
 895    foreach ($dependencies as $depend_name => $depend_requirements)
 896    {
 897       $version = preg_split('/\./', $depend_requirements['version'], 3);
 898       $version[0] = intval($version[0]);
 899       $version[1] = intval($version[1]);
 900       $version[2] = intval($version[2]);
 901
 902       $force_dependency_inclusion = !$depend_requirements['activate'];
 903
 904       if (!check_plugin_version($depend_name, $version[0], $version[1],
 905                                 $version[2], $force_dependency_inclusion))
 906          $missing_or_bad[$depend_name] = $depend_requirements;
 907    }
 908
 909    if (empty($missing_or_bad)) return TRUE;
 910
 911
 912    // get non-parsed required versions
 913    //
 914    $non_parsed_dependencies = get_plugin_dependencies($plugin_name,
 915                                                       $force_inclusion,
 916                                                       FALSE);
 917    $return_array = array();
 918    foreach ($missing_or_bad as $depend_name => $ignore)
 919       $return_array[$depend_name] = $non_parsed_dependencies[$depend_name];
 920
 921    return $return_array;
 922
 923 }
 924