drupal/core/modules/file/file.install

<?php

/**
 * @file
 * Install, update and uninstall functions for File module.
 */

use Drupal\Core\Entity\Entity\EntityViewDisplay;

/**
 * Implements hook_schema().
 */
function file_schema() {
  $schema['file_usage'] = [
    'description' => 'Track where a file is used.',
    'fields' => [
      'fid' => [
        'description' => 'File ID.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ],
      'module' => [
        'description' => 'The name of the module that is using the file.',
        'type' => 'varchar_ascii',
        'length' => DRUPAL_EXTENSION_NAME_MAX_LENGTH,
        'not null' => TRUE,
        'default' => '',
      ],
      'type' => [
        'description' => 'The name of the object type in which the file is used.',
        'type' => 'varchar_ascii',
        'length' => 64,
        'not null' => TRUE,
        'default' => '',
      ],
      'id' => [
        'description' => 'The primary key of the object using the file.',
        'type' => 'varchar_ascii',
        'length' => 64,
        'not null' => TRUE,
        'default' => 0,
      ],
      'count' => [
        'description' => 'The number of times this file is used by this object.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ],
    ],
    'primary key' => ['fid', 'type', 'id', 'module'],
    'indexes' => [
      'type_id' => ['type', 'id'],
      'fid_count' => ['fid', 'count'],
      'fid_module' => ['fid', 'module'],
    ],
  ];
  return $schema;
}

/**
 * Implements hook_requirements().
 *
 * Display information about getting upload progress bars working.
 */
function file_requirements($phase) {
  $requirements = [];

  // Check the server's ability to indicate upload progress.
  if ($phase == 'runtime') {
    $description = NULL;
    $implementation = file_progress_implementation();
    $server_software = \Drupal::request()->server->get('SERVER_SOFTWARE');

    // Test the web server identity.
    if (preg_match("/Nginx/i", $server_software)) {
      $is_nginx = TRUE;
      $is_apache = FALSE;
      $fastcgi = FALSE;
    }
    elseif (preg_match("/Apache/i", $server_software)) {
      $is_nginx = FALSE;
      $is_apache = TRUE;
      $fastcgi = strpos($server_software, 'mod_fastcgi') !== FALSE || strpos($server_software, 'mod_fcgi') !== FALSE;
    }
    else {
      $is_nginx = FALSE;
      $is_apache = FALSE;
      $fastcgi = FALSE;
    }

    if (!$is_apache && !$is_nginx) {
      $value = t('Not enabled');
      $description = t('Your server is not capable of displaying file upload progress. File upload progress requires an Apache server running PHP with mod_php or Nginx with PHP-FPM.');
    }
    elseif ($fastcgi) {
      $value = t('Not enabled');
      $description = t('Your server is not capable of displaying file upload progress. File upload progress requires PHP be run with mod_php or PHP-FPM and not as FastCGI.');
    }
    elseif (!$implementation) {
      $value = t('Not enabled');
      $description = t('Your server is capable of displaying file upload progress, but does not have the required libraries. It is recommended to install the <a href="http://pecl.php.net/package/uploadprogress">PECL uploadprogress library</a>.');
    }
    elseif ($implementation == 'apc') {
      $value = t('Enabled (<a href="http://php.net/manual/apcu.configuration.php#ini.apcu.rfc1867">APC RFC1867</a>)');
      $description = t('Your server is capable of displaying file upload progress using APC RFC1867. Note that only one upload at a time is supported. It is recommended to use the <a href="http://pecl.php.net/package/uploadprogress">PECL uploadprogress library</a> if possible.');
    }
    elseif ($implementation == 'uploadprogress') {
      $value = t('Enabled (<a href="http://pecl.php.net/package/uploadprogress">PECL uploadprogress</a>)');
    }
    $requirements['file_progress'] = [
      'title' => t('Upload progress'),
      'value' => $value,
      'description' => $description,
    ];
  }

  return $requirements;
}

/**
 * Prevent unused files from being deleted.
 */
function file_update_8300() {
  // Disable deletion of unused permanent files.
  \Drupal::configFactory()->getEditable('file.settings')
    ->set('make_unused_managed_files_temporary', FALSE)
    ->save();

  return t('Files that have no remaining usages are no longer deleted by default.');
}

/**
 * Add 'use_description_as_link_text' setting to file field formatters.
 */
function file_update_8001() {
  $displays = EntityViewDisplay::loadMultiple();
  foreach ($displays as $display) {
    /** @var \Drupal\Core\Entity\Entity\EntityViewDisplay $display */
    $fields_settings = $display->get('content');
    $changed = FALSE;
    foreach ($fields_settings as $field_name => $settings) {
      if (!empty($settings['type'])) {
        switch ($settings['type']) {
          // The file_table formatter never displayed available descriptions
          // before, so we disable this option to ensure backward compatibility.
          case 'file_table':
            $fields_settings[$field_name]['settings']['use_description_as_link_text'] = FALSE;
            $changed = TRUE;
            break;

          // The file_default formatter always displayed available descriptions
          // before, so we enable this option to ensure backward compatibility.
          case 'file_default':
            $fields_settings[$field_name]['settings']['use_description_as_link_text'] = TRUE;
            $changed = TRUE;
            break;
        }
      }
    }
    if ($changed === TRUE) {
      $display->set('content', $fields_settings)->save();
    }
  }
}

/**
 * Set the 'owner' entity key and update the field.
 */
function file_update_8700() {
  $definition_update_manager = \Drupal::entityDefinitionUpdateManager();
  $entity_type = $definition_update_manager->getEntityType('file');
  $keys = $entity_type->getKeys();
  $keys['owner'] = 'uid';
  $entity_type->set('entity_keys', $keys);
  $definition_update_manager->updateEntityType($entity_type);
  $definition_update_manager->updateFieldStorageDefinition($definition_update_manager->getFieldStorageDefinition('uid', 'file'));
}