<?php

// $Id: batch.inc,v 1.14 2007/12/20 11:57:20 goba Exp $

/**

 * @file Batch processing API for processes to run in multiple HTTP requests.

 */

/**

 * State-based dispatcher for the batch processing page.

 */

function _batch_page() {

  $batch =& batch_get();

  // Retrieve the current state of batch from db.

  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'])))) {

    $batch = unserialize($data);

  }

  else {

    return FALSE;

  }

  // Register database update for end of processing.

  register_shutdown_function('_batch_shutdown');

  $op = isset($_REQUEST['op']) ? $_REQUEST['op'] : '';

  $output = NULL;

  switch ($op) {

    case 'start':

      $output = _batch_start();

      break;

    case 'do':

      // JS-version AJAX callback.

      _batch_do();

      break;

    case 'do_nojs':

      // Non-JS progress page.

      $output = _batch_progress_page_nojs();

      break;

    case 'finished':

      $output = _batch_finished();

      break;

  }

  return $output;

}

/**

 * Initiate the batch processing

 */

function _batch_start() {

  // Choose between the JS and non-JS version.

  // JS-enabled users are identified through the 'has_js' cookie set in drupal.js.

  // If the user did not visit any JS enabled page during his browser session,

  // he gets the non-JS version...

  if (isset($_COOKIE['has_js']) && $_COOKIE['has_js']) {

    return _batch_progress_page_js();

  }

  else {

    return _batch_progress_page_nojs();

  }

}

/**

 * Batch processing page with JavaScript support.

 */

function _batch_progress_page_js() {

  $batch = batch_get();

  // The first batch set gets to set the page title

  // and the initialization and error messages.

  $current_set = _batch_current_set();

  drupal_set_title($current_set['title']);

  drupal_add_js('misc/progress.js', 'core', 'header', FALSE, FALSE);

  $url = url($batch['url'], array('query' => array('id' => $batch['id'])));

  $js_setting = array(

    'batch' => array(

      'errorMessage' => $current_set['error_message'] .'<br/>'. $batch['error_message'],

      'initMessage' => $current_set['init_message'],

      'uri' => $url,

    ),

  );

  drupal_add_js($js_setting, 'setting');

  drupal_add_js('misc/batch.js', 'core', 'header', FALSE, FALSE);

  $output = '<div id="progress"></div>';

  return $output;

}

/**

 * Do one pass of execution and inform back the browser about progression

 * (used for JavaScript-mode only).

 */

function _batch_do() {

  // HTTP POST required

  if ($_SERVER['REQUEST_METHOD'] != 'POST') {

    drupal_set_message(t('HTTP POST is required.'), 'error');

    drupal_set_title(t('Error'));

    return '';

  }

  // Perform actual processing.

  list($percentage, $message) = _batch_process();

  drupal_json(array('status' => TRUE, 'percentage' => $percentage, 'message' => $message));

}

/**

 * Batch processing page without JavaScript support.

 */

function _batch_progress_page_nojs() {

  $batch =& batch_get();

  $current_set = _batch_current_set();

  drupal_set_title($current_set['title']);

  $new_op = 'do_nojs';

  if (!isset($batch['running'])) {

    // This is the first page so we return some output immediately.

    $percentage = 0;

    $message = $current_set['init_message'];

    $batch['running'] = TRUE;

  }

  else {

    // This is one of the later requests: do some processing first.

    // Error handling: if PHP dies due to a fatal error (e.g. non-existant

    // function), it will output whatever is in the output buffer,

    // followed by the error message.

    ob_start();

    $fallback = $current_set['error_message'] .'<br/>'. $batch['error_message'];

    $fallback = theme('maintenance_page', $fallback, FALSE, FALSE);

    // We strip the end of the page using a marker in the template, so any

    // additional HTML output by PHP shows up inside the page rather than

    // below it. While this causes invalid HTML, the same would be true if

    // we didn't, as content is not allowed to appear after </html> anyway.

    list($fallback) = explode('<!--partial-->', $fallback);

    print $fallback;

    // Perform actual processing.

    list($percentage, $message) = _batch_process($batch);

    if ($percentage == 100) {

      $new_op = 'finished';

    }

    // PHP did not die : remove the fallback output.

    ob_end_clean();

  }

  $url = url($batch['url'], array('query' => array('id' => $batch['id'], 'op' => $new_op)));

  drupal_set_html_head('<meta http-equiv="Refresh" content="0; URL='. $url .'">');

  $output = theme('progress_bar', $percentage, $message);

  return $output;

}

/**

 * Advance batch processing for 1 second (or process the whole batch if it

 * was not set for progressive execution - e.g forms submitted by drupal_execute).

 */

function _batch_process() {

  $batch =& batch_get();

  $current_set =& _batch_current_set();

  $set_changed = TRUE;

  if ($batch['progressive']) {

    timer_start('batch_processing');

  }

  while (!$current_set['success']) {

    // If this is the first time we iterate this batch set in the current

    // request, we check if it requires an additional file for functions

    // definitions.

    if ($set_changed && isset($current_set['file']) && is_file($current_set['file'])) {

      include_once($current_set['file']);

    }

    $finished = 1;

    $task_message = '';

    if ((list($function, $args) = reset($current_set['operations'])) && function_exists($function)) {

      // Build the 'context' array, execute the function call,

      // and retrieve the user message.

      $batch_context = array('sandbox' => &$current_set['sandbox'], 'results' => &$current_set['results'], 'finished' => &$finished, 'message' => &$task_message);

      // Process the current operation.

      call_user_func_array($function, array_merge($args, array(&$batch_context)));

    }

    if ($finished == 1) {

      // Make sure this step isn't counted double when computing $current.

      $finished = 0;

      // Remove the operation and clear the sandbox.

      array_shift($current_set['operations']);

      $current_set['sandbox'] = array();

    }

    // If the batch set is completed, browse through the remaining sets,

    // executing 'control sets' (stored form submit handlers) along the way -

    // this might in turn insert new batch sets.

    // Stop when we find a set that actually has operations.

    $set_changed = FALSE;

    $old_set = $current_set;

    while (empty($current_set['operations']) && ($current_set['success'] = TRUE) && _batch_next_set()) {

      $current_set =& _batch_current_set();

      $set_changed = TRUE;

    }

    // At this point, either $current_set is a 'real' batch set (has operations),

    // or all sets have been completed.

    // If we're in progressive mode, stop after 1 second.

    if ($batch['progressive'] && timer_read('batch_processing') > 1000) {

      break;

    }

  }

  if ($batch['progressive']) {

    // Gather progress information.

    // Reporting 100% progress will cause the whole batch to be considered

    // processed. If processing was paused right after moving to a new set,

    // we have to use the info from the new (unprocessed) one.

    if ($set_changed && isset($current_set['operations'])) {

      // Processing will continue with a fresh batch set.

      $remaining = count($current_set['operations']);

      $total = $current_set['total'];

      $progress_message = $current_set['init_message'];

      $task_message = '';

    }

    else {

      $remaining = count($old_set['operations']);

      $total = $old_set['total'];

      $progress_message = $old_set['progress_message'];

    }

    $current    = $total - $remaining + $finished;

    $percentage = $total ? floor($current / $total * 100) : 100;

    $values = array(

      '@remaining'  => $remaining,

      '@total'      => $total,

      '@current'    => floor($current),

      '@percentage' => $percentage,

      );

    $message = strtr($progress_message, $values) .'<br/>';

    $message .= $task_message ? $task_message : '&nbsp';

    return array($percentage, $message);

  }

  else {

    // If we're not in progressive mode, the whole batch has been processed by now.

    return _batch_finished();

  }

}

/**

 * Retrieve the batch set being currently processed.

 */

function &_batch_current_set() {

  $batch =& batch_get();

  return $batch['sets'][$batch['current_set']];

}

/**

 * Move execution to the next batch set if any, executing the stored

 * form _submit handlers along the way (thus possibly inserting

 * additional batch sets).

 */

function _batch_next_set() {

  $batch =& batch_get();

  if (isset($batch['sets'][$batch['current_set'] + 1])) {

    $batch['current_set']++;

    $current_set =& _batch_current_set();

    if (isset($current_set['form_submit']) && ($function = $current_set['form_submit']) && function_exists($function)) {

      // We use our stored copies of $form and $form_state, to account for

      // possible alteration by the submit handlers.

      $function($batch['form'], $batch['form_state']);

    }

    return TRUE;

  }

}

/**

 * End the batch processing:

 * Call the 'finished' callbacks to allow custom handling of results,

 * and resolve page redirection.

 */

function _batch_finished() {

  $batch =& batch_get();

  // Execute the 'finished' callbacks for each batch set.

  foreach ($batch['sets'] as $key => $batch_set) {

    if (isset($batch_set['finished'])) {

      // Check if the set requires an additional file for functions definitions.

      if (isset($batch_set['file']) && is_file($batch_set['file'])) {

        include_once($batch_set['file']);

      }

      if (function_exists($batch_set['finished'])) {

        $batch_set['finished']($batch_set['success'], $batch_set['results'], $batch_set['operations']);

      }

    }

  }

  // Cleanup the batch table and unset the global $batch variable.

  if ($batch['progressive']) {

    db_query("DELETE FROM {batch} WHERE bid = %d", $batch['id']);

  }

  $_batch = $batch;

  $batch = NULL;

  // Redirect if needed.

  if ($_batch['progressive']) {

    // Put back the 'destination' that was saved in batch_process().

    if (isset($_batch['destination'])) {

      $_REQUEST['destination'] = $_batch['destination'];

    }

    // Use $_batch['form_state']['redirect'], or $_batch['redirect'],

    // or $_batch['source_page'].

    if (isset($_batch['form_state']['redirect'])) {

      $redirect = $_batch['form_state']['redirect'];

    }

    elseif (isset($_batch['redirect'])) {

      $redirect = $_batch['redirect'];

    }

    else {

      $redirect = $_batch['source_page'];

    }

    // Let drupal_redirect_form handle redirection logic.

    $form = isset($batch['form']) ? $batch['form'] : array();

    if (empty($_batch['form_state']['rebuild']) && empty($_batch['form_state']['storage'])) {

      drupal_redirect_form($form, $redirect);

    }

    // We get here if $form['#redirect'] was FALSE, or if the form is a

    // multi-step form. We save the final $form_state value to be retrieved

    // by drupal_get_form, and we redirect to the originating page.

    $_SESSION['batch_form_state'] = $_batch['form_state'];

    drupal_goto($_batch['source_page']);

  }

}

/**

 * Shutdown function: store the batch data for next request,

 * or clear the table if the batch is finished.

 */

function _batch_shutdown() {

  if ($batch = batch_get()) {

    db_query("UPDATE {batch} SET batch = '%s' WHERE bid = %d", serialize($batch), $batch['id']);

  }

}