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   1  <?php
   2  
   3  // This file is part of Moodle - http://moodle.org/
   4  //
   5  // Moodle is free software: you can redistribute it and/or modify
   6  // it under the terms of the GNU General Public License as published by
   7  // the Free Software Foundation, either version 3 of the License, or
   8  // (at your option) any later version.
   9  //
  10  // Moodle is distributed in the hope that it will be useful,
  11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  // GNU General Public License for more details.
  14  //
  15  // You should have received a copy of the GNU General Public License
  16  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17  
  18  /**
  19   * plagiarismlib.php - Contains core Plagiarism related functions.
  20   *
  21   * @since Moodle 2.0
  22   * @package    moodlecore
  23   * @subpackage plagiarism
  24   * @copyright  2010 Dan Marsden http://danmarsden.com
  25   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26   */
  27  
  28  ///// GENERIC PLAGIARISM FUNCTIONS ////////////////////////////////////////////////////
  29  
  30  if (!defined('MOODLE_INTERNAL')) {
  31      die('Direct access to this script is forbidden.');    ///  It must be included from a Moodle page
  32  }
  33  
  34  /**
  35   * displays the similarity score and provides a link to the full report if allowed.
  36   *
  37   * @param object  $linkarray contains all relevant information for the plugin to generate a link
  38   * @return string - url to allow login/viewing of a similarity report
  39   */
  40  function plagiarism_get_links($linkarray) {
  41      global $CFG;
  42      if (empty($CFG->enableplagiarism)) {
  43          return '';
  44      }
  45      $plagiarismplugins = plagiarism_load_available_plugins();
  46      $output = '';
  47      foreach($plagiarismplugins as $plugin => $dir) {
  48          require_once($dir.'/lib.php');
  49          $plagiarismclass = "plagiarism_plugin_$plugin";
  50          $plagiarismplugin = new $plagiarismclass;
  51          $output .= $plagiarismplugin->get_links($linkarray);
  52      }
  53      return $output;
  54  }
  55  
  56  /**
  57   * returns array of plagiarism details about specified file
  58   *
  59   * @param int $cmid
  60   * @param int $userid
  61   * @param object $file moodle file object
  62   * @return array - sets of details about specified file, one array of details per plagiarism plugin
  63   *  - each set contains at least 'analyzed', 'score', 'reporturl'
  64   */
  65  function plagiarism_get_file_results($cmid, $userid, $file) {
  66      global $CFG;
  67      $allresults = array();
  68      if (empty($CFG->enableplagiarism)) {
  69          return $allresults;
  70      }
  71      $plagiarismplugins = plagiarism_load_available_plugins();
  72      foreach($plagiarismplugins as $plugin => $dir) {
  73          require_once($dir.'/lib.php');
  74          $plagiarismclass = "plagiarism_plugin_$plugin";
  75          $plagiarismplugin = new $plagiarismclass;
  76          $allresults[] = $plagiarismplugin->get_file_results($cmid, $userid, $file);
  77      }
  78      return $allresults;
  79  }
  80  
  81  /**
  82   * saves/updates plagiarism settings from a modules config page - called by course/modedit.php
  83   *
  84   * @param object $data - form data
  85   */
  86  function plagiarism_save_form_elements($data) {
  87      global $CFG;
  88      if (empty($CFG->enableplagiarism)) {
  89          return '';
  90      }
  91      $plagiarismplugins = plagiarism_load_available_plugins();
  92      foreach($plagiarismplugins as $plugin => $dir) {
  93          require_once($dir.'/lib.php');
  94          $plagiarismclass = "plagiarism_plugin_$plugin";
  95          $plagiarismplugin = new $plagiarismclass;
  96          $plagiarismplugin->save_form_elements($data);
  97      }
  98  }
  99  
 100  /**
 101   * adds the list of plagiarism settings to a form - called inside modules that have enabled plagiarism
 102   *
 103   * @param object $mform - Moodle form object
 104   * @param object $context - context object
 105   * @param string $modulename - Name of the module
 106   */
 107  function plagiarism_get_form_elements_module($mform, $context, $modulename = "") {
 108      global $CFG;
 109      if (empty($CFG->enableplagiarism)) {
 110          return '';
 111      }
 112      $plagiarismplugins = plagiarism_load_available_plugins();
 113      foreach($plagiarismplugins as $plugin => $dir) {
 114          require_once($dir.'/lib.php');
 115          $plagiarismclass = "plagiarism_plugin_$plugin";
 116          $plagiarismplugin = new $plagiarismclass;
 117          $plagiarismplugin->get_form_elements_module($mform, $context, $modulename);
 118      }
 119  }
 120  /**
 121   * updates the status of all files within a module
 122   *
 123   * @param object $course - full Course object
 124   * @param object $cm - full cm object
 125   * @return string
 126   */
 127  function plagiarism_update_status($course, $cm) {
 128      global $CFG;
 129      if (empty($CFG->enableplagiarism)) {
 130          return '';
 131      }
 132      $plagiarismplugins = plagiarism_load_available_plugins();
 133      $output = '';
 134      foreach($plagiarismplugins as $plugin => $dir) {
 135          require_once($dir.'/lib.php');
 136          $plagiarismclass = "plagiarism_plugin_$plugin";
 137          $plagiarismplugin = new $plagiarismclass;
 138          $output .= $plagiarismplugin->update_status($course, $cm);
 139      }
 140      return $output;
 141  }
 142  
 143  /**
 144  * Function that prints the student disclosure notifying that the files will be checked for plagiarism
 145  * @param integer $cmid - the cmid of this module
 146  * @return string
 147  */
 148  function plagiarism_print_disclosure($cmid) {
 149      global $CFG;
 150      if (empty($CFG->enableplagiarism)) {
 151          return '';
 152      }
 153      $plagiarismplugins = plagiarism_load_available_plugins();
 154      $output = '';
 155      foreach($plagiarismplugins as $plugin => $dir) {
 156          require_once($dir.'/lib.php');
 157          $plagiarismclass = "plagiarism_plugin_$plugin";
 158          $plagiarismplugin = new $plagiarismclass;
 159          $output .= $plagiarismplugin->print_disclosure($cmid);
 160      }
 161      return $output;
 162  }
 163  /**
 164   * used by admin/cron.php to get similarity scores from submitted files.
 165   *
 166   */
 167  function plagiarism_cron() {
 168      global $CFG;
 169      if (empty($CFG->enableplagiarism)) {
 170          return '';
 171      }
 172      $plagiarismplugins = plagiarism_load_available_plugins();
 173      foreach($plagiarismplugins as $plugin => $dir) {
 174          require_once($dir.'/lib.php');
 175          $plagiarismclass = "plagiarism_plugin_$plugin";
 176          $plagiarismplugin = new $plagiarismclass;
 177          if (method_exists($plagiarismplugin, 'cron')) {
 178              mtrace('Processing cron function for plagiarism_plugin_' . $plugin . '...', '');
 179              cron_trace_time_and_memory();
 180              $plagiarismplugin->cron();
 181          }
 182      }
 183  }
 184  /**
 185   * helper function - also loads lib file of plagiarism plugin
 186   * @return array of available plugins
 187   */
 188  function plagiarism_load_available_plugins() {
 189      global $CFG;
 190      if (empty($CFG->enableplagiarism)) {
 191          return array();
 192      }
 193      $plagiarismplugins = core_component::get_plugin_list('plagiarism');
 194      $availableplugins = array();
 195      foreach($plagiarismplugins as $plugin => $dir) {
 196          //check this plugin is enabled and a lib file exists.
 197          if (get_config('plagiarism', $plugin."_use") && file_exists($dir."/lib.php")) {
 198              require_once($dir.'/lib.php');
 199              $plagiarismclass = "plagiarism_plugin_$plugin";
 200              if (class_exists($plagiarismclass)) {
 201                  $availableplugins[$plugin] = $dir;
 202              }
 203          }
 204      }
 205      return $availableplugins;
 206  }