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   1  <?php
   2  
   3  /**
   4   * @file Batch processing API for processes to run in multiple HTTP requests.
   5   */
   6  
   7  /**
   8   * State-based dispatcher for the batch processing page.
   9   */
  10  function _batch_page() {
  11    $batch =& batch_get();
  12  
  13    // Retrieve the current state of batch from db.
  14    if (isset($_REQUEST['id']) && $data = db_result(db_query("SELECT batch FROM {batch} WHERE bid = %d AND token = '%s'", $_REQUEST['id'], drupal_get_token($_REQUEST['id'])))) {
  15      $batch = unserialize($data);
  16    }
  17    else {
  18      return FALSE;
  19    }
  20  
  21    // Register database update for end of processing.
  22    register_shutdown_function('_batch_shutdown');
  23  
  24    $op = isset($_REQUEST['op']) ? $_REQUEST['op'] : '';
  25    $output = NULL;
  26    switch ($op) {
  27      case 'start':
  28        $output = _batch_start();
  29        break;
  30  
  31      case 'do':
  32        // JS-version AJAX callback.
  33        _batch_do();
  34        break;
  35  
  36      case 'do_nojs':
  37        // Non-JS progress page.
  38        $output = _batch_progress_page_nojs();
  39        break;
  40  
  41      case 'finished':
  42        $output = _batch_finished();
  43        break;
  44    }
  45  
  46    return $output;
  47  }
  48  
  49  /**
  50   * Initiate the batch processing
  51   */
  52  function _batch_start() {
  53    // Choose between the JS and non-JS version.
  54    // JS-enabled users are identified through the 'has_js' cookie set in drupal.js.
  55    // If the user did not visit any JS enabled page during his browser session,
  56    // he gets the non-JS version...
  57    if (isset($_COOKIE['has_js']) && $_COOKIE['has_js']) {
  58      return _batch_progress_page_js();
  59    }
  60    else {
  61      return _batch_progress_page_nojs();
  62    }
  63  }
  64  
  65  /**
  66   * Batch processing page with JavaScript support.
  67   */
  68  function _batch_progress_page_js() {
  69    $batch = batch_get();
  70  
  71    // The first batch set gets to set the page title
  72    // and the initialization and error messages.
  73    $current_set = _batch_current_set();
  74    drupal_set_title($current_set['title']);
  75    drupal_add_js('misc/progress.js', 'core', 'header', FALSE, FALSE);
  76  
  77    $url = url($batch['url'], array('query' => array('id' => $batch['id'])));
  78    $js_setting = array(
  79      'batch' => array(
  80        'errorMessage' => $current_set['error_message'] .'<br/>'. $batch['error_message'],
  81        'initMessage' => $current_set['init_message'],
  82        'uri' => $url,
  83      ),
  84    );
  85    drupal_add_js($js_setting, 'setting');
  86    drupal_add_js('misc/batch.js', 'core', 'header', FALSE, FALSE);
  87  
  88    $output = '<div id="progress"></div>';
  89    return $output;
  90  }
  91  
  92  /**
  93   * Do one pass of execution and inform back the browser about progression
  94   * (used for JavaScript-mode only).
  95   */
  96  function _batch_do() {
  97    // HTTP POST required
  98    if ($_SERVER['REQUEST_METHOD'] != 'POST') {
  99      drupal_set_message(t('HTTP POST is required.'), 'error');
 100      drupal_set_title(t('Error'));
 101      return '';
 102    }
 103  
 104    // Perform actual processing.
 105    list($percentage, $message) = _batch_process();
 106  
 107    drupal_json(array('status' => TRUE, 'percentage' => $percentage, 'message' => $message));
 108  }
 109  
 110  /**
 111   * Batch processing page without JavaScript support.
 112   */
 113  function _batch_progress_page_nojs() {
 114    $batch =& batch_get();
 115    $current_set = _batch_current_set();
 116  
 117    drupal_set_title($current_set['title']);
 118  
 119    $new_op = 'do_nojs';
 120  
 121    if (!isset($batch['running'])) {
 122      // This is the first page so we return some output immediately.
 123      $percentage = 0;
 124      $message = $current_set['init_message'];
 125      $batch['running'] = TRUE;
 126    }
 127    else {
 128      // This is one of the later requests: do some processing first.
 129  
 130      // Error handling: if PHP dies due to a fatal error (e.g. non-existant
 131      // function), it will output whatever is in the output buffer,
 132      // followed by the error message.
 133      ob_start();
 134      $fallback = $current_set['error_message'] .'<br/>'. $batch['error_message'];
 135      drupal_maintenance_theme();
 136      $fallback = theme('maintenance_page', $fallback, FALSE, FALSE);
 137  
 138      // We strip the end of the page using a marker in the template, so any
 139      // additional HTML output by PHP shows up inside the page rather than
 140      // below it. While this causes invalid HTML, the same would be true if
 141      // we didn't, as content is not allowed to appear after </html> anyway.
 142      list($fallback) = explode('<!--partial-->', $fallback);
 143      print $fallback;
 144  
 145      // Perform actual processing.
 146      list($percentage, $message) = _batch_process($batch);
 147      if ($percentage == 100) {
 148        $new_op = 'finished';
 149      }
 150  
 151      // PHP did not die : remove the fallback output.
 152      ob_end_clean();
 153    }
 154  
 155    $url = url($batch['url'], array('query' => array('id' => $batch['id'], 'op' => $new_op)));
 156    drupal_set_html_head('<meta http-equiv="Refresh" content="0; URL='. $url .'">');
 157    $output = theme('progress_bar', $percentage, $message);
 158    return $output;
 159  }
 160  
 161  /**
 162   * Advance batch processing for 1 second (or process the whole batch if it
 163   * was not set for progressive execution - e.g forms submitted by drupal_execute).
 164   */
 165  function _batch_process() {
 166    $batch =& batch_get();
 167    $current_set =& _batch_current_set();
 168    $set_changed = TRUE;
 169  
 170    if ($batch['progressive']) {
 171      timer_start('batch_processing');
 172    }
 173  
 174    while (!$current_set['success']) {
 175      // If this is the first time we iterate this batch set in the current
 176      // request, we check if it requires an additional file for functions
 177      // definitions.
 178      if ($set_changed && isset($current_set['file']) && is_file($current_set['file'])) {
 179        include_once($current_set['file']);
 180      }
 181  
 182      $finished = 1;
 183      $task_message = '';
 184      if ((list($function, $args) = reset($current_set['operations'])) && function_exists($function)) {
 185        // Build the 'context' array, execute the function call,
 186        // and retrieve the user message.
 187        $batch_context = array('sandbox' => &$current_set['sandbox'], 'results' => &$current_set['results'], 'finished' => &$finished, 'message' => &$task_message);
 188        // Process the current operation.
 189        call_user_func_array($function, array_merge($args, array(&$batch_context)));
 190      }
 191  
 192      if ($finished >= 1) {
 193        // Make sure this step isn't counted double when computing $current.
 194        $finished = 0;
 195        // Remove the operation and clear the sandbox.
 196        array_shift($current_set['operations']);
 197        $current_set['sandbox'] = array();
 198      }
 199  
 200      // If the batch set is completed, browse through the remaining sets,
 201      // executing 'control sets' (stored form submit handlers) along the way -
 202      // this might in turn insert new batch sets.
 203      // Stop when we find a set that actually has operations.
 204      $set_changed = FALSE;
 205      $old_set = $current_set;
 206      while (empty($current_set['operations']) && ($current_set['success'] = TRUE) && _batch_next_set()) {
 207        $current_set =& _batch_current_set();
 208        $set_changed = TRUE;
 209      }
 210      // At this point, either $current_set is a 'real' batch set (has operations),
 211      // or all sets have been completed.
 212  
 213      // If we're in progressive mode, stop after 1 second.
 214      if ($batch['progressive'] && timer_read('batch_processing') > 1000) {
 215        break;
 216      }
 217    }
 218  
 219    if ($batch['progressive']) {
 220      // Gather progress information.
 221  
 222      // Reporting 100% progress will cause the whole batch to be considered
 223      // processed. If processing was paused right after moving to a new set,
 224      // we have to use the info from the new (unprocessed) one.
 225      if ($set_changed && isset($current_set['operations'])) {
 226        // Processing will continue with a fresh batch set.
 227        $remaining = count($current_set['operations']);
 228        $total = $current_set['total'];
 229        $progress_message = $current_set['init_message'];
 230        $task_message = '';
 231      }
 232      else {
 233        $remaining = count($old_set['operations']);
 234        $total = $old_set['total'];
 235        $progress_message = $old_set['progress_message'];
 236      }
 237  
 238      $current    = $total - $remaining + $finished;
 239      $percentage = $total ? floor($current / $total * 100) : 100;
 240      $values = array(
 241        '@remaining'  => $remaining,
 242        '@total'      => $total,
 243        '@current'    => floor($current),
 244        '@percentage' => $percentage,
 245        );
 246      $message = strtr($progress_message, $values) .'<br/>';
 247      $message .= $task_message ? $task_message : '&nbsp;';
 248  
 249      return array($percentage, $message);
 250    }
 251    else {
 252      // If we're not in progressive mode, the whole batch has been processed by now.
 253      return _batch_finished();
 254    }
 255  
 256  }
 257  
 258  /**
 259   * Retrieve the batch set being currently processed.
 260   */
 261  function &_batch_current_set() {
 262    $batch =& batch_get();
 263    return $batch['sets'][$batch['current_set']];
 264  }
 265  
 266  /**
 267   * Move execution to the next batch set if any, executing the stored
 268   * form _submit handlers along the way (thus possibly inserting
 269   * additional batch sets).
 270   */
 271  function _batch_next_set() {
 272    $batch =& batch_get();
 273    if (isset($batch['sets'][$batch['current_set'] + 1])) {
 274      $batch['current_set']++;
 275      $current_set =& _batch_current_set();
 276      if (isset($current_set['form_submit']) && ($function = $current_set['form_submit']) && function_exists($function)) {
 277        // We use our stored copies of $form and $form_state, to account for
 278        // possible alteration by the submit handlers.
 279        $function($batch['form'], $batch['form_state']);
 280      }
 281      return TRUE;
 282    }
 283  }
 284  
 285  /**
 286   * End the batch processing:
 287   * Call the 'finished' callbacks to allow custom handling of results,
 288   * and resolve page redirection.
 289   */
 290  function _batch_finished() {
 291    $batch =& batch_get();
 292  
 293    // Execute the 'finished' callbacks for each batch set.
 294    foreach ($batch['sets'] as $key => $batch_set) {
 295      if (isset($batch_set['finished'])) {
 296        // Check if the set requires an additional file for functions definitions.
 297        if (isset($batch_set['file']) && is_file($batch_set['file'])) {
 298          include_once($batch_set['file']);
 299        }
 300        if (function_exists($batch_set['finished'])) {
 301          $batch_set['finished']($batch_set['success'], $batch_set['results'], $batch_set['operations']);
 302        }
 303      }
 304    }
 305  
 306    // Cleanup the batch table and unset the global $batch variable.
 307    if ($batch['progressive']) {
 308      db_query("DELETE FROM {batch} WHERE bid = %d", $batch['id']);
 309    }
 310    $_batch = $batch;
 311    $batch = NULL;
 312  
 313    // Redirect if needed.
 314    if ($_batch['progressive']) {
 315      // Put back the 'destination' that was saved in batch_process().
 316      if (isset($_batch['destination'])) {
 317        $_REQUEST['destination'] = $_batch['destination'];
 318      }
 319  
 320      // Use $_batch['form_state']['redirect'], or $_batch['redirect'],
 321      // or $_batch['source_page'].
 322      if (isset($_batch['form_state']['redirect'])) {
 323        $redirect = $_batch['form_state']['redirect'];
 324      }
 325      elseif (isset($_batch['redirect'])) {
 326        $redirect = $_batch['redirect'];
 327      }
 328      else {
 329        $redirect = $_batch['source_page'];
 330      }
 331  
 332      // Let drupal_redirect_form handle redirection logic.
 333      $form = isset($batch['form']) ? $batch['form'] : array();
 334      if (empty($_batch['form_state']['rebuild']) && empty($_batch['form_state']['storage'])) {
 335        drupal_redirect_form($form, $redirect);
 336      }
 337  
 338      // We get here if $form['#redirect'] was FALSE, or if the form is a
 339      // multi-step form. We save the final $form_state value to be retrieved
 340      // by drupal_get_form, and we redirect to the originating page.
 341      $_SESSION['batch_form_state'] = $_batch['form_state'];
 342      drupal_goto($_batch['source_page']);
 343    }
 344  }
 345  
 346  /**
 347   * Shutdown function: store the batch data for next request,
 348   * or clear the table if the batch is finished.
 349   */
 350  function _batch_shutdown() {
 351    if ($batch = batch_get()) {
 352      db_query("UPDATE {batch} SET batch = '%s' WHERE bid = %d", serialize($batch), $batch['id']);
 353    }
 354  }