update.inc 39.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10
<?php

/**
 * @file
 * Drupal database update API.
 *
 * This file contains functions to perform database updates for a Drupal
 * installation. It is included and used extensively by update.php.
 */

11
use Drupal\Component\Graph\Graph;
12
use Drupal\Core\Config\FileStorage;
13

14
/**
15
 * Minimum schema version of Drupal 7 required for upgrade to Drupal 8.
16
 *
17
 * Upgrades from Drupal 7 to Drupal 8 require that Drupal 7 be running
18
 * the most recent version, or the upgrade could fail. We can't easily
19
 * check the Drupal 7 version once the update process has begun, so instead
20 21
 * we check the schema version of system.module in the system table.
 */
22
const REQUIRED_D7_SCHEMA_VERSION = '7069';
23

24
/**
25
 * Disable any items in the {system} table that are not core compatible.
26 27 28
 */
function update_fix_compatibility() {
  $incompatible = array();
29 30 31 32
  $result = db_query("SELECT name, type, status FROM {system} WHERE status = 1 AND type IN ('module','theme')");
  foreach ($result as $row) {
    if (update_check_incompatibility($row->name, $row->type)) {
      $incompatible[] = $row->name;
33 34 35
    }
  }
  if (!empty($incompatible)) {
36 37 38 39
    db_update('system')
      ->fields(array('status' => 0))
      ->condition('name', $incompatible, 'IN')
      ->execute();
40 41 42 43 44 45 46 47 48 49 50
  }
}

/**
 * Helper function to test compatibility of a module or theme.
 */
function update_check_incompatibility($name, $type = 'module') {
  static $themes, $modules;

  // Store values of expensive functions for future use.
  if (empty($themes) || empty($modules)) {
51 52 53 54
    // We need to do a full rebuild here to make sure the database reflects any
    // code changes that were made in the filesystem before the update script
    // was initiated.
    $themes = system_rebuild_theme_data();
55
    $modules = system_rebuild_module_data();
56 57 58 59 60 61 62 63 64 65 66
  }

  if ($type == 'module' && isset($modules[$name])) {
    $file = $modules[$name];
  }
  elseif ($type == 'theme' && isset($themes[$name])) {
    $file = $themes[$name];
  }
  if (!isset($file)
      || !isset($file->info['core'])
      || $file->info['core'] != DRUPAL_CORE_COMPATIBILITY
67
      || version_compare(phpversion(), $file->info['php']) < 0) {
68 69 70 71 72 73
    return TRUE;
  }
  return FALSE;
}

/**
74
 * Performs extra steps required to bootstrap when using a Drupal 7 database.
75
 *
76 77
 * Users who still have a Drupal 7 database (and are in the process of
 * updating to Drupal 8) need extra help before a full bootstrap can be
78 79 80 81
 * achieved. This function does the necessary preliminary work that allows
 * the bootstrap to be successful.
 *
 * No access check has been performed when this function is called, so no
82
 * irreversible changes to the database are made here.
83
 */
84
function update_prepare_d8_bootstrap() {
85 86
  // Allow the database system to work even if the registry has not been
  // created yet.
87
  include_once DRUPAL_ROOT . '/core/includes/install.inc';
88
  drupal_bootstrap(DRUPAL_BOOTSTRAP_DATABASE);
89

90 91
  // If the site has not updated to Drupal 8 yet, check to make sure that it is
  // running an up-to-date version of Drupal 7 before proceeding. Note this has
92 93
  // to happen AFTER the database bootstraps because of
  // drupal_get_installed_schema_version().
94
  $system_schema = drupal_get_installed_schema_version('system');
95
  if ($system_schema < 8000) {
96
    $has_required_schema = $system_schema >= REQUIRED_D7_SCHEMA_VERSION;
97
    $requirements = array(
98 99 100
      'drupal 7 version' => array(
        'title' => 'Drupal 7 version',
        'value' => $has_required_schema ? 'You are running a current version of Drupal 7.' : 'You are not running a current version of Drupal 7',
101
        'severity' => $has_required_schema ? REQUIREMENT_OK : REQUIREMENT_ERROR,
102
        'description' => $has_required_schema ? '' : 'Please update your Drupal 7 installation to the most recent version before attempting to upgrade to Drupal 8',
103 104
      ),
    );
105
    if ($has_required_schema) {
106 107 108 109 110 111
      // Bootstrap variables so we can update theme while preparing the update
      // process.
      drupal_bootstrap(DRUPAL_BOOTSTRAP_VARIABLES);
      // Update the dynamic include paths that might be used before running the
      // proper update functions.
      update_prepare_stored_includes();
112 113
      // Update the environment for the language bootstrap if needed.
      update_prepare_d8_language();
114 115 116 117 118 119 120 121 122 123

      // Change language column to langcode in url_alias.
      if (db_table_exists('url_alias') && db_field_exists('url_alias', 'language')) {
        db_drop_index('url_alias', 'alias_language_pid');
        db_drop_index('url_alias', 'source_language_pid');
        $langcode_spec = array(
          'description' => "The language code this alias is for; if 'und', the alias will be used for unknown languages. Each Drupal path can have an alias for each supported language.",
          'type' => 'varchar',
          'length' => 12,
          'not null' => TRUE,
124
          'default' => '',
125 126 127 128 129 130 131 132 133
        );
        $langcode_indexes = array('indexes' =>
          array(
            'alias_langcode_pid' => array('alias', 'langcode', 'pid'),
            'source_langcode_pid' => array('source', 'langcode', 'pid'),
          ),
        );
        db_change_field('url_alias', 'language', 'langcode', $langcode_spec, $langcode_indexes);
      }
134 135 136 137
    }
  }
}

138 139 140 141 142
/**
 * Fix stored include paths to match the "/core" migration.
 */
function update_prepare_stored_includes() {
  // Update language negotiation settings.
143
  foreach (language_types_get_all() as $language_type) {
144
    $negotiation = variable_get("language_negotiation_$language_type", array());
145 146
    foreach ($negotiation as $method_id => &$method) {
      if (isset($method['file']) && $method['file'] == 'includes/locale.inc') {
147
        $method['file'] = 'core/modules/language/language.negotiation.inc';
148 149 150 151 152 153
      }
    }
    variable_set("language_negotiation_$language_type", $negotiation);
  }
}

154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186
/**
 * Prepare Drupal 8 language changes for the bootstrap if needed.
 */
function update_prepare_d8_language() {
  if (db_table_exists('languages')) {
    $languages = db_select('languages', 'l')
      ->fields('l')
      ->execute();
    $plurals = array();
    $javascript = array();
    $prefixes = array();
    $domains = array();
    foreach ($languages as $language) {
      $plurals[$language->language] = array(
        'plurals' => $language->plurals,
        'formula' => $language->formula,
      );
      $javascript[$language->language] = $language->javascript;
      $prefixes[$language->language] = $language->prefix;
      $domains[$language->language] = $language->domain;
    }
    variable_set('locale_translation_plurals', $plurals);
    variable_set('locale_translation_javascript', $javascript);
    variable_set('locale_language_negotiation_url_prefixes', $prefixes);
    variable_set('locale_language_negotiation_url_domains', $domains);

    // Drop now unneeded columns.
    db_drop_field('languages', 'plurals');
    db_drop_field('languages', 'formula');
    db_drop_field('languages', 'javascript');
    db_drop_field('languages', 'prefix');
    db_drop_field('languages', 'domain');
    db_drop_field('languages', 'native');
187 188 189 190
    db_drop_field('languages', 'enabled');

    // Update language count.
    variable_set('language_count', db_query('SELECT COUNT(language) FROM {languages}')->fetchField());
191 192 193 194

    // Rename the languages table to language.
    db_rename_table('languages', 'language');

195 196 197
    // Install/enable the language module. We need to use the update specific
    // version of this function to ensure schema conflicts don't happen due to
    // our updated data.
198 199 200
    $modules = array('language');
    update_module_add_to_system($modules);
    update_module_enable($modules);
201

202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236
    // Rename language column to langcode and set it again as the primary key.
    if (db_field_exists('language', 'language')) {
      db_drop_primary_key('language');
      $langcode_spec = array(
        'type' => 'varchar',
        'length' => 12,
        'not null' => TRUE,
        'default' => '',
        'description' => "Language code, e.g. 'de' or 'en-US'.",
      );
      db_change_field('language', 'language', 'langcode', $langcode_spec, array('primary key' => array('langcode')));
    }

    // Update the 'language_default' system variable, if configured.
    $language_default = variable_get('language_default');
    if (!empty($language_default) && isset($language_default->language)) {
      $language_default->langcode = $language_default->language;
      unset($language_default->language);
      // In D8, the 'language_default' is not anymore an object, but an array,
      // so make sure that the new value that is saved into this variable is an
      // array.
      variable_set('language_default', (array) $language_default);
     }

    // Adds the locked column and saves the special languages.
    if (!db_field_exists('language', 'locked')) {
      $locked_spec = array(
        'type' => 'int',
        'size' => 'tiny',
        'not null' => TRUE,
        'default' => 0,
        'description' => 'A boolean indicating whether the administrator can edit or delete the language.',
      );
      db_add_field('language', 'locked', $locked_spec);

237 238
      $max_language_weight = db_query('SELECT MAX(weight) FROM {language}')->fetchField();
      $languages = language_locked_languages($max_language_weight);
239 240 241 242 243 244 245 246 247 248 249 250
      foreach ($languages as $language) {
        db_insert('language')
          ->fields(array(
            'langcode' => $language->langcode,
            'name' => $language->name,
            'weight' => $language->weight,
            // These languages are locked, default to enabled.
            'locked' => 1,
          ))
          ->execute();
      }
    }
251 252 253 254 255 256 257 258 259

    // Update the 'language_default' system variable with the langcode change.
    $language_default = variable_get('language_default');
    if (!empty($language_default)) {
      if (isset($language_default->language)) {
        $language_default->langcode = $language_default->language;
        unset($language_default->language);
      }
      unset($language_default->enabled);
260 261 262 263
      // In D8, the 'language_default' is not anymore an object, but an array,
      // so make sure that the new value that is saved into this variable is an
      // array.
      variable_set('language_default', (array) $language_default);
264
    }
265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299
  }
}

/**
 * Adds modules to the system table in a Drupal core update.
 *
 * @param $modules
 *   Array of module names.
 */
function update_module_add_to_system($modules = array()) {
  // Insert module data, so we can enable the module. Calling a full module
  // list rebuild so early is costly and complex, so we just have a stop-gap.
  $info_defaults = array(
    'dependencies' => array(),
    'description' => '',
    'package' => 'Other',
    'version' => NULL,
    'php' => DRUPAL_MINIMUM_PHP,
    'files' => array(),
    'bootstrap' => 0,
  );
  foreach ($modules as $module) {
    $module_info = drupal_parse_info_file('core/modules/' . $module . '/' . $module . '.info');
    db_insert('system')
      ->fields(array(
        'filename' => 'core/modules/' . $module . '/' . $module . '.module',
        'name' => $module,
        'type' => 'module',
        'status' => 0,
        'bootstrap' => 0,
        'schema_version' => -1,
        'weight' => 0,
        'info' => serialize($module_info + $info_defaults),
      ))
      ->execute();
300
  }
301 302 303
}

/**
304
 * Perform Drupal 7.x to 8.x updates that are required for update.php
305 306
 * to function properly.
 *
307
 * This function runs when update.php is run the first time for 8.x,
308 309 310 311
 * even before updates are selected or performed. It is important
 * that if updates are not ultimately performed that no changes are
 * made which make it impossible to continue using the prior version.
 */
312
function update_fix_d8_requirements() {
313
  global $conf;
314

315 316 317
  if (drupal_get_installed_schema_version('system') < 8000 && !variable_get('update_d8_requirements', FALSE)) {
    // @todo: Make critical, first-run changes to the database here.
    variable_set('update_d8_requirements', TRUE);
318
  }
319
}
320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341

/**
 * Helper function to install a new module in Drupal 8 via hook_update_N().
 */
function update_module_enable(array $modules) {
  foreach ($modules as $module) {
    // Check for initial schema and install it. The schema version of a newly
    // installed module is always 0. Using 8000 here would be inconsistent
    // since $module_update_8000() may involve a schema change, and we want
    // to install the schema as it was before any updates were added.
    $function = $module . '_schema_0';
    if (function_exists($function)) {
      $schema = $function();
      foreach ($schema as $table => $spec) {
        db_create_table($table, $spec);
      }
    }
    // Change the schema version from SCHEMA_UNINSTALLED to 0, so any module
    // updates since the module's inception are executed in a core upgrade.
    db_update('system')
      ->condition('type', 'module')
      ->condition('name', $module)
342
      ->fields(array('schema_version' => 0, 'status' => 1))
343 344
      ->execute();

345 346 347
    // system_list_reset() is in module.inc but that would only be available
    // once the variable bootstrap is done.
    require_once DRUPAL_ROOT . '/core/includes/module.inc';
348 349 350 351
    system_list_reset();
    //  @todo: figure out what to do about hook_install() and hook_enable().
  }
}
352

353
/**
354
 * Perform one update and store the results for display on finished page.
355
 *
356 357 358 359 360 361 362 363 364 365
 * If an update function completes successfully, it should return a message
 * as a string indicating success, for example:
 * @code
 * return t('New index added successfully.');
 * @endcode
 *
 * Alternatively, it may return nothing. In that case, no message
 * will be displayed at all.
 *
 * If it fails for whatever reason, it should throw an instance of
366 367
 * Drupal\Core\Utility\UpdateException with an appropriate error message, for
 * example:
368
 * @code
369 370
 * use Drupal\Core\Utility\UpdateException;
 * throw new UpdateException(t('Description of what went wrong'));
371 372
 * @endcode
 *
373 374 375 376
 * If an exception is thrown, the current update and all updates that depend on
 * it will be aborted. The schema version will not be updated in this case, and
 * all the aborted updates will continue to appear on update.php as updates
 * that have not yet been run.
377
 *
378 379 380 381 382
 * If an update function needs to be re-run as part of a batch process, it
 * should accept the $sandbox array by reference as its first parameter
 * and set the #finished property to the percentage completed that it is, as a
 * fraction of 1.
 *
383 384 385 386
 * @param $module
 *   The module whose update will be run.
 * @param $number
 *   The update number to run.
387 388 389 390
 * @param $dependency_map
 *   An array whose keys are the names of all update functions that will be
 *   performed during this batch process, and whose values are arrays of other
 *   update functions that each one depends on.
391
 * @param $context
392 393 394
 *   The batch context array.
 *
 * @see update_resolve_dependencies()
395
 */
396 397 398 399 400
function update_do_one($module, $number, $dependency_map, &$context) {
  $function = $module . '_update_' . $number;

  // If this update was aborted in a previous step, or has a dependency that
  // was aborted in a previous step, go no further.
401
  if (!empty($context['results']['#abort']) && array_intersect($context['results']['#abort'], array_merge($dependency_map, array($function)))) {
402 403 404
    return;
  }

405
  $ret = array();
406
  if (function_exists($function)) {
407 408 409 410
    try {
      $ret['results']['query'] = $function($context['sandbox']);
      $ret['results']['success'] = TRUE;
    }
411 412 413
    // @TODO We may want to do different error handling for different
    // exception types, but for now we'll just log the exception and
    // return the message for printing.
414
    catch (Exception $e) {
415 416
      watchdog_exception('update', $e);

417
      require_once DRUPAL_ROOT . '/core/includes/errors.inc';
418
      $variables = _drupal_decode_exception($e);
419 420
      // The exception message is run through check_plain() by _drupal_decode_exception().
      $ret['#abort'] = array('success' => FALSE, 'query' => t('%type: !message in %function (line %line of %file).', $variables));
421
    }
422 423
  }

424 425 426 427 428
  if (isset($context['sandbox']['#finished'])) {
    $context['finished'] = $context['sandbox']['#finished'];
    unset($context['sandbox']['#finished']);
  }

429 430 431 432 433 434 435 436 437
  if (!isset($context['results'][$module])) {
    $context['results'][$module] = array();
  }
  if (!isset($context['results'][$module][$number])) {
    $context['results'][$module][$number] = array();
  }
  $context['results'][$module][$number] = array_merge($context['results'][$module][$number], $ret);

  if (!empty($ret['#abort'])) {
438 439
    // Record this function in the list of updates that were aborted.
    $context['results']['#abort'][] = $function;
440
  }
441

442
  // Record the schema update if it was completed successfully.
443
  if ($context['finished'] == 1 && empty($ret['#abort'])) {
444 445 446 447 448 449
    drupal_set_installed_schema_version($module, $number);
  }

  $context['message'] = 'Updating ' . check_plain($module) . ' module';
}

450 451 452 453
/**
 * Start the database update batch process.
 *
 * @param $start
454 455 456 457 458
 *   An array whose keys contain the names of modules to be updated during the
 *   current batch process, and whose values contain the number of the first
 *   requested update for that module. The actual updates that are run (and the
 *   order they are run in) will depend on the results of passing this data
 *   through the update dependency system.
459 460 461 462 463 464 465
 * @param $redirect
 *   Path to redirect to when the batch has finished processing.
 * @param $url
 *   URL of the batch processing page (should only be used for separate
 *   scripts like update.php).
 * @param $batch
 *   Optional parameters to pass into the batch API.
466 467 468
 * @param $redirect_callback
 *   (optional) Specify a function to be called to redirect to the progressive
 *   processing page.
469 470
 *
 * @see update_resolve_dependencies()
471
 */
472
function update_batch($start, $redirect = NULL, $url = NULL, $batch = array(), $redirect_callback = 'drupal_goto') {
473 474
  // During the update, bring the site offline so that schema changes do not
  // affect visiting users.
475 476 477
  $_SESSION['maintenance_mode'] = variable_get('maintenance_mode', FALSE);
  if ($_SESSION['maintenance_mode'] == FALSE) {
    variable_set('maintenance_mode', TRUE);
478 479
  }

480 481 482 483 484 485 486 487 488 489 490 491 492
  // Resolve any update dependencies to determine the actual updates that will
  // be run and the order they will be run in.
  $updates = update_resolve_dependencies($start);

  // Store the dependencies for each update function in an array which the
  // batch API can pass in to the batch operation each time it is called. (We
  // do not store the entire update dependency array here because it is
  // potentially very large.)
  $dependency_map = array();
  foreach ($updates as $function => $update) {
    $dependency_map[$function] = !empty($update['reverse_paths']) ? array_keys($update['reverse_paths']) : array();
  }

493
  $operations = array();
494 495 496 497 498 499 500 501
  foreach ($updates as $update) {
    if ($update['allowed']) {
      // Set the installed version of each module so updates will start at the
      // correct place. (The updates are already sorted, so we can simply base
      // this on the first one we come across in the above foreach loop.)
      if (isset($start[$update['module']])) {
        drupal_set_installed_schema_version($update['module'], $update['number'] - 1);
        unset($start[$update['module']]);
502
      }
503
      // Add this update function to the batch.
504 505
      $function = $update['module'] . '_update_' . $update['number'];
      $operations[] = array('update_do_one', array($update['module'], $update['number'], $dependency_map[$function]));
506 507 508 509 510 511 512 513
    }
  }
  $batch['operations'] = $operations;
  $batch += array(
    'title' => 'Updating',
    'init_message' => 'Starting updates',
    'error_message' => 'An unrecoverable error has occurred. You can find the error message below. It is advised to copy it to the clipboard for reference.',
    'finished' => 'update_finished',
514
    'file' => 'core/includes/update.inc',
515 516
  );
  batch_set($batch);
517
  batch_process($redirect, $url, $redirect_callback);
518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545
}

/**
 * Finish the update process and store results for eventual display.
 *
 * After the updates run, all caches are flushed. The update results are
 * stored into the session (for example, to be displayed on the update results
 * page in update.php). Additionally, if the site was off-line, now that the
 * update process is completed, the site is set back online.
 *
 * @param $success
 *   Indicate that the batch API tasks were all completed successfully.
 * @param $results
 *   An array of all the results that were updated in update_do_one().
 * @param $operations
 *   A list of all the operations that had not been completed by the batch API.
 *
 * @see update_batch()
 */
function update_finished($success, $results, $operations) {
  // Clear the caches in case the data has been updated.
  drupal_flush_all_caches();

  $_SESSION['update_results'] = $results;
  $_SESSION['update_success'] = $success;
  $_SESSION['updates_remaining'] = $operations;

  // Now that the update is done, we can put the site back online if it was
546 547 548 549
  // previously in maintenance mode.
  if (isset($_SESSION['maintenance_mode']) && $_SESSION['maintenance_mode'] == FALSE) {
    variable_set('maintenance_mode', FALSE);
    unset($_SESSION['maintenance_mode']);
550 551 552
  }
}

553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573
/**
 * Return a list of all the pending database updates.
 *
 * @return
 *   An associative array keyed by module name which contains all information
 *   about database updates that need to be run, and any updates that are not
 *   going to proceed due to missing requirements. The system module will
 *   always be listed first.
 *
 *   The subarray for each module can contain the following keys:
 *   - start: The starting update that is to be processed. If this does not
 *       exist then do not process any updates for this module as there are
 *       other requirements that need to be resolved.
 *   - warning: Any warnings about why this module can not be updated.
 *   - pending: An array of all the pending updates for the module including
 *       the update number and the description from source code comment for
 *       each update function. This array is keyed by the update number.
 */
function update_get_update_list() {
  // Make sure that the system module is first in the list of updates.
  $ret = array('system' => array());
574

575 576
  $modules = drupal_get_installed_schema_version(NULL, FALSE, TRUE);
  foreach ($modules as $module => $schema_version) {
577 578 579 580 581
    // Skip uninstalled and incompatible modules.
    if ($schema_version == SCHEMA_UNINSTALLED || update_check_incompatibility($module)) {
      continue;
    }
    // Otherwise, get the list of updates defined by this module.
582
    $updates = drupal_get_schema_versions($module);
583
    if ($updates !== FALSE) {
584 585 586 587 588 589 590
      // module_invoke returns NULL for nonexisting hooks, so if no updates
      // are removed, it will == 0.
      $last_removed = module_invoke($module, 'update_last_removed');
      if ($schema_version < $last_removed) {
        $ret[$module]['warning'] = '<em>' . $module . '</em> module can not be updated. Its schema version is ' . $schema_version . '. Updates up to and including ' . $last_removed . ' have been removed in this release. In order to update <em>' . $module . '</em> module, you will first <a href="http://drupal.org/upgrade">need to upgrade</a> to the last version in which these updates were available.';
        continue;
      }
591

592 593 594
      $updates = drupal_map_assoc($updates);
      foreach (array_keys($updates) as $update) {
        if ($update > $schema_version) {
595
          // The description for an update comes from its Doxygen.
596
          $func = new ReflectionFunction($module . '_update_' . $update);
597 598 599 600
          $description = str_replace(array("\n", '*', '/'), '', $func->getDocComment());
          $ret[$module]['pending'][$update] = "$update - $description";
          if (!isset($ret[$module]['start'])) {
            $ret[$module]['start'] = $update;
601 602 603 604 605 606 607 608
          }
        }
      }
      if (!isset($ret[$module]['start']) && isset($ret[$module]['pending'])) {
        $ret[$module]['start'] = $schema_version;
      }
    }
  }
609

610 611 612 613 614 615
  if (empty($ret['system'])) {
    unset($ret['system']);
  }
  return $ret;
}

616 617 618 619 620 621 622 623 624 625 626 627
/**
 * Resolves dependencies in a set of module updates, and orders them correctly.
 *
 * This function receives a list of requested module updates and determines an
 * appropriate order to run them in such that all update dependencies are met.
 * Any updates whose dependencies cannot be met are included in the returned
 * array but have the key 'allowed' set to FALSE; the calling function should
 * take responsibility for ensuring that these updates are ultimately not
 * performed.
 *
 * In addition, the returned array also includes detailed information about the
 * dependency chain for each update, as provided by the depth-first search
628
 * algorithm in Drupal\Component\Graph\Graph::searchAndSort().
629 630 631 632 633 634 635 636 637 638 639 640
 *
 * @param $starting_updates
 *   An array whose keys contain the names of modules with updates to be run
 *   and whose values contain the number of the first requested update for that
 *   module.
 *
 * @return
 *   An array whose keys are the names of all update functions within the
 *   provided modules that would need to be run in order to fulfill the
 *   request, arranged in the order in which the update functions should be
 *   run. (This includes the provided starting update for each module and all
 *   subsequent updates that are available.) The values are themselves arrays
641 642 643 644 645
 *   containing all the keys provided by the
 *   Drupal\Component\Graph\Graph::searchAndSort() algorithm, which encode
 *   detailed information about the dependency chain for this update function
 *   (for example: 'paths', 'reverse_paths', 'weight', and 'component'), as well
 *   as the following additional keys:
646 647 648 649 650 651 652 653 654
 *   - 'allowed': A boolean which is TRUE when the update function's
 *     dependencies are met, and FALSE otherwise. Calling functions should
 *     inspect this value before running the update.
 *   - 'missing_dependencies': An array containing the names of any other
 *     update functions that are required by this one but that are unavailable
 *     to be run. This array will be empty when 'allowed' is TRUE.
 *   - 'module': The name of the module that this update function belongs to.
 *   - 'number': The number of this update function within that module.
 *
655
 * @see Drupal\Component\Graph\Graph::searchAndSort()
656 657 658 659 660 661
 */
function update_resolve_dependencies($starting_updates) {
  // Obtain a dependency graph for the requested update functions.
  $update_functions = update_get_update_function_list($starting_updates);
  $graph = update_build_dependency_graph($update_functions);

662 663 664
  // Perform the depth-first search and sort on the results.
  $graph_object = new Graph($graph);
  $graph = $graph_object->searchAndSort();
665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716
  uasort($graph, 'drupal_sort_weight');

  foreach ($graph as $function => &$data) {
    $module = $data['module'];
    $number = $data['number'];
    // If the update function is missing and has not yet been performed, mark
    // it and everything that ultimately depends on it as disallowed.
    if (update_is_missing($module, $number, $update_functions) && !update_already_performed($module, $number)) {
      $data['allowed'] = FALSE;
      foreach (array_keys($data['paths']) as $dependent) {
        $graph[$dependent]['allowed'] = FALSE;
        $graph[$dependent]['missing_dependencies'][] = $function;
      }
    }
    elseif (!isset($data['allowed'])) {
      $data['allowed'] = TRUE;
      $data['missing_dependencies'] = array();
    }
    // Now that we have finished processing this function, remove it from the
    // graph if it was not part of the original list. This ensures that we
    // never try to run any updates that were not specifically requested.
    if (!isset($update_functions[$module][$number])) {
      unset($graph[$function]);
    }
  }

  return $graph;
}

/**
 * Returns an organized list of update functions for a set of modules.
 *
 * @param $starting_updates
 *   An array whose keys contain the names of modules and whose values contain
 *   the number of the first requested update for that module.
 *
 * @return
 *   An array containing all the update functions that should be run for each
 *   module, including the provided starting update and all subsequent updates
 *   that are available. The keys of the array contain the module names, and
 *   each value is an ordered array of update functions, keyed by the update
 *   number.
 *
 * @see update_resolve_dependencies()
 */
function update_get_update_function_list($starting_updates) {
  // Go through each module and find all updates that we need (including the
  // first update that was requested and any updates that run after it).
  $update_functions = array();
  foreach ($starting_updates as $module => $version) {
    $update_functions[$module] = array();
    $updates = drupal_get_schema_versions($module);
717 718 719 720 721 722 723
    if ($updates !== FALSE) {
      $max_version = max($updates);
      if ($version <= $max_version) {
        foreach ($updates as $update) {
          if ($update >= $version) {
            $update_functions[$module][$update] = $module . '_update_' . $update;
          }
724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741
        }
      }
    }
  }
  return $update_functions;
}

/**
 * Constructs a graph which encodes the dependencies between module updates.
 *
 * This function returns an associative array which contains a "directed graph"
 * representation of the dependencies between a provided list of update
 * functions, as well as any outside update functions that they directly depend
 * on but that were not in the provided list. The vertices of the graph
 * represent the update functions themselves, and each edge represents a
 * requirement that the first update function needs to run before the second.
 * For example, consider this graph:
 *
742
 * system_update_8000 ---> system_update_8001 ---> system_update_8002
743
 *
744 745
 * Visually, this indicates that system_update_8000() must run before
 * system_update_8001(), which in turn must run before system_update_8002().
746 747 748 749 750 751 752 753 754 755 756 757 758
 *
 * The function takes into account standard dependencies within each module, as
 * shown above (i.e., the fact that each module's updates must run in numerical
 * order), but also finds any cross-module dependencies that are defined by
 * modules which implement hook_update_dependencies(), and builds them into the
 * graph as well.
 *
 * @param $update_functions
 *   An organized array of update functions, in the format returned by
 *   update_get_update_function_list().
 *
 * @return
 *   A multidimensional array representing the dependency graph, suitable for
759 760 761 762 763 764
 *   passing in to Drupal\Component\Graph\Graph::searchAndSort(), but with extra
 *   information about each update function also included. Each array key
 *   contains the name of an update function, including all update functions
 *   from the provided list as well as any outside update functions which they
 *   directly depend on. Each value is an associative array containing the
 *   following keys:
765
 *   - 'edges': A representation of any other update functions that immediately
766 767
 *     depend on this one. See Drupal\Component\Graph\Graph::searchAndSort() for
 *     more details on the format.
768 769 770
 *   - 'module': The name of the module that this update function belongs to.
 *   - 'number': The number of this update function within that module.
 *
771
 * @see Drupal\Component\Graph\Graph::searchAndSort()
772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797
 * @see update_resolve_dependencies()
 */
function update_build_dependency_graph($update_functions) {
  // Initialize an array that will define a directed graph representing the
  // dependencies between update functions.
  $graph = array();

  // Go through each update function and build an initial list of dependencies.
  foreach ($update_functions as $module => $functions) {
    $previous_function = NULL;
    foreach ($functions as $number => $function) {
      // Add an edge to the directed graph representing the fact that each
      // update function in a given module must run after the update that
      // numerically precedes it.
      if ($previous_function) {
        $graph[$previous_function]['edges'][$function] = TRUE;
      }
      $previous_function = $function;

      // Define the module and update number associated with this function.
      $graph[$function]['module'] = $module;
      $graph[$function]['number'] = $number;
    }
  }

  // Now add any explicit update dependencies declared by modules.
798
  $update_dependencies = update_retrieve_dependencies();
799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849
  foreach ($graph as $function => $data) {
    if (!empty($update_dependencies[$data['module']][$data['number']])) {
      foreach ($update_dependencies[$data['module']][$data['number']] as $module => $number) {
        $dependency = $module . '_update_' . $number;
        $graph[$dependency]['edges'][$function] = TRUE;
        $graph[$dependency]['module'] = $module;
        $graph[$dependency]['number'] = $number;
      }
    }
  }

  return $graph;
}

/**
 * Determines if a module update is missing or unavailable.
 *
 * @param $module
 *   The name of the module.
 * @param $number
 *   The number of the update within that module.
 * @param $update_functions
 *   An organized array of update functions, in the format returned by
 *   update_get_update_function_list(). This should represent all module
 *   updates that are requested to run at the time this function is called.
 *
 * @return
 *   TRUE if the provided module update is not installed or is not in the
 *   provided list of updates to run; FALSE otherwise.
 */
function update_is_missing($module, $number, $update_functions) {
  return !isset($update_functions[$module][$number]) || !function_exists($update_functions[$module][$number]);
}

/**
 * Determines if a module update has already been performed.
 *
 * @param $module
 *   The name of the module.
 * @param $number
 *   The number of the update within that module.
 *
 * @return
 *   TRUE if the database schema indicates that the update has already been
 *   performed; FALSE otherwise.
 */
function update_already_performed($module, $number) {
  return $number <= drupal_get_installed_schema_version($module);
}

/**
850
 * Invoke hook_update_dependencies() in all installed modules.
851
 *
852 853 854 855
 * This function is similar to module_invoke_all(), with the main difference
 * that it does not require that a module be enabled to invoke its hook, only
 * that it be installed. This allows the update system to properly perform
 * updates even on modules that are currently disabled.
856 857
 *
 * @return
858 859
 *   An array of return values obtained by merging the results of the
 *   hook_update_dependencies() implementations in all installed modules.
860 861
 *
 * @see module_invoke_all()
862
 * @see hook_update_dependencies()
863
 */
864
function update_retrieve_dependencies() {
865
  $return = array();
866 867
  // Get a list of installed modules, arranged so that we invoke their hooks in
  // the same order that module_invoke_all() does.
868
  $modules = db_query("SELECT name FROM {system} WHERE type = 'module' AND schema_version <> :schema ORDER BY weight ASC, name ASC", array(':schema' => SCHEMA_UNINSTALLED))->fetchCol();
869
  foreach ($modules as $module) {
870
    $function = $module . '_update_dependencies';
871
    if (function_exists($function)) {
872 873 874 875 876 877 878 879 880
      $result = $function();
      // Each implementation of hook_update_dependencies() returns a
      // multidimensional, associative array containing some keys that
      // represent module names (which are strings) and other keys that
      // represent update function numbers (which are integers). We cannot use
      // array_merge_recursive() to properly merge these results, since it
      // treats strings and integers differently. Therefore, we have to
      // explicitly loop through the expected array structure here and perform
      // the merge manually.
881
      if (isset($result) && is_array($result)) {
882 883 884 885 886 887 888 889 890 891 892
        foreach ($result as $module => $module_data) {
          foreach ($module_data as $update => $update_data) {
            foreach ($update_data as $module_dependency => $update_dependency) {
              // If there are redundant dependencies declared for the same
              // update function (so that it is declared to depend on more than
              // one update from a particular module), record the dependency on
              // the highest numbered update here, since that automatically
              // implies the previous ones. For example, if one module's
              // implementation of hook_update_dependencies() required this
              // ordering:
              //
893
              // system_update_8001 ---> user_update_8000
894 895 896 897
              //
              // but another module's implementation of the hook required this
              // one:
              //
898
              // system_update_8002 ---> user_update_8000
899
              //
900 901
              // we record the second one, since system_update_8001() is always
              // guaranteed to run before system_update_8002() anyway (within
902 903 904 905 906 907 908 909
              // an individual module, updates are always run in numerical
              // order).
              if (!isset($return[$module][$update][$module_dependency]) || $update_dependency > $return[$module][$update][$module_dependency]) {
                $return[$module][$update][$module_dependency] = $update_dependency;
              }
            }
          }
        }
910 911 912 913 914 915 916
      }
    }
  }

  return $return;
}

917 918
/**
 * Updates config with values set on Drupal 7.x
919
 *
920 921 922
 * Provide a generalised method to migrate variables from Drupal 7 to Drupal 8's
 * configuration management system.
 *
923 924 925 926 927
 * @param string $config_name
 *   The configuration object name to retrieve.
 * @param array $variable_map
 *   An associative array that maps old variables names to new configuration
 *   object keys; e.g.:
928
 *   @code
929
 *     array('old_variable' => 'new_config.sub_key')
930
 *   @endcode
931 932
 *   This would migrate the value contained in variable name 'old_variable' into
 *   the data key 'new_config.sub_key' of the configuration object $config_name.
933
 */
934 935 936 937
function update_variables_to_config($config_name, array $variable_map) {
  // Build the new configuration object.
  // This potentially loads an existing configuration object, in case another
  // update function migrated configuration values into $config_name already.
938
  $config = config($config_name);
939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958
  $original_data = $config->get();

  // Extract the module namespace/owner from the configuration object name.
  $module = strtok($config_name, '.');

  // Load and set default configuration values.
  // Throws a FileStorageReadException if there is no default configuration
  // file, which is required to exist.
  $file = new FileStorage($config_name);
  $file->setPath(drupal_get_path('module', $module) . '/config');
  $default_data = $file->read();

  // Merge any possibly existing original data into default values.
  // Only relevant when being called repetitively on the same config object.
  if (!empty($original_data)) {
    $data = drupal_array_merge_deep($default_data, $original_data);
  }
  else {
    $data = $default_data;
  }
959

960 961 962 963 964 965 966 967 968 969 970 971 972 973 974
  // Apply the default values.
  $config->setData($data);

  // Fetch existing variables.
  $variables = db_query('SELECT name, value FROM {variable} WHERE name IN (:variables)', array(':variables' => array_keys($variable_map)))->fetchAllKeyed();

  // Set configuration values according to the provided variable mapping.
  foreach ($variable_map as $variable_name => $config_key) {
    // This function migrates variables regardless of their value, including
    // NULL values. Any possibly required customizations need to be performed
    // manually, either via variable_set() before calling this function or via
    // config() after calling this function.
    if (isset($variables[$variable_name])) {
      $value = unserialize($variables[$variable_name]);
      $config->set($config_key, $value);
975 976
    }
  }
977 978 979 980 981 982

  // Save the configuration object.
  $config->save();

  // Delete the migrated variables.
  db_delete('variable')->condition('name', array_keys($variable_map), 'IN')->execute();
983 984
}

985
/**
986
 * @defgroup update-api-7.x-to-8.x Update versions of API functions
987 988 989 990 991 992 993 994 995
 * @{
 * Functions similar to normal API function but not firing hooks.
 *
 * During update, it is impossible to judge the consequences of firing a hook
 * as it might hit a module not yet updated. So simplified versions of some
 * core APIs are provided.
 */

/**
996
 * @} End of "defgroup update-api-7.x-to-8.x".
997
 */