--- /dev/null
+<?php
+
+namespace Drupal\update;
+
+/**
+ * Manages project update information.
+ */
+interface UpdateManagerInterface {
+
+ /**
+ * Project is missing security update(s).
+ */
+ const NOT_SECURE = 1;
+
+ /**
+ * Current release has been unpublished and is no longer available.
+ */
+ const REVOKED = 2;
+
+ /**
+ * Current release is no longer supported by the project maintainer.
+ */
+ const NOT_SUPPORTED = 3;
+
+ /**
+ * Project has a new release available, but it is not a security release.
+ */
+ const NOT_CURRENT = 4;
+
+ /**
+ * Project is up to date.
+ */
+ const CURRENT = 5;
+
+ /**
+ * Fetches an array of installed and enabled projects.
+ *
+ * This is only responsible for generating an array of projects (taking into
+ * account projects that include more than one module or theme). Other
+ * information like the specific version and install type (official release,
+ * dev snapshot, etc) is handled later in update_process_project_info() since
+ * that logic is only required when preparing the status report, not for
+ * fetching the available release data.
+ *
+ * This array is fairly expensive to construct, since it involves a lot of
+ * disk I/O, so we store the results. However, since this is not the data
+ * about available updates fetched from the network, it is acceptable to
+ * invalidate it somewhat quickly. If we keep this data for very long, site
+ * administrators are more likely to see incorrect results if they upgrade to
+ * a newer version of a module or theme but do not visit certain pages that
+ * automatically clear this data.
+ *
+ * @return array
+ * An associative array of currently enabled projects keyed by the
+ * machine-readable project short name. Each project contains:
+ * - name: The machine-readable project short name.
+ * - info: An array with values from the main .info.yml file for this
+ * project.
+ * - name: The human-readable name of the project.
+ * - package: The package that the project is grouped under.
+ * - version: The version of the project.
+ * - project: The Drupal.org project name.
+ * - datestamp: The date stamp of the project's main .info.yml file.
+ * - _info_file_ctime: The maximum file change time for all of the
+ * .info.yml
+ * files included in this project.
+ * - datestamp: The date stamp when the project was released, if known.
+ * - includes: An associative array containing all projects included with
+ * this project, keyed by the machine-readable short name with the
+ * human-readable name as value.
+ * - project_type: The type of project. Allowed values are 'module' and
+ * 'theme'.
+ * - project_status: This indicates if the project is enabled and will
+ * always be TRUE, as the function only returns enabled projects.
+ *
+ * @see update_process_project_info()
+ * @see update_calculate_project_data()
+ * @see \Drupal\update\UpdateManager::projectStorage()
+ */
+ public function getProjects();
+
+ /**
+ * Processes a step in batch for fetching available update data.
+ *
+ * @param array $context
+ * Reference to an array used for Batch API storage.
+ */
+ public function fetchDataBatch(&$context);
+
+ /**
+ * Clears out all the available update data and initiates re-fetching.
+ */
+ public function refreshUpdateData();
+
+ /**
+ * Retrieves update storage data or empties it.
+ *
+ * Two very expensive arrays computed by this module are the list of all
+ * installed modules and themes (and .info.yml data, project associations,
+ * etc), and the current status of the site relative to the currently
+ * available releases. These two arrays are stored and used whenever possible.
+ * The data is cleared whenever the administrator visits the status report,
+ * available updates report, or the module or theme administration pages,
+ * since we should always recompute the most current values on any of those
+ * pages.
+ *
+ * Note: while both of these arrays are expensive to compute (in terms of disk
+ * I/O and some fairly heavy CPU processing), neither of these is the actual
+ * data about available updates that we have to fetch over the network from
+ * updates.drupal.org. That information is stored in the
+ * 'update_available_releases' collection -- it needs to persist longer than 1
+ * hour and never get invalidated just by visiting a page on the site.
+ *
+ * @param string $key
+ * The key of data to return. Valid options are 'update_project_data' and
+ * 'update_project_projects'.
+ *
+ * @return array
+ * The stored value of the $projects array generated by
+ * update_calculate_project_data() or
+ * \Drupal\Update\UpdateManager::getProjects(), or an empty array when the
+ * storage is cleared.
+ * array when the storage is cleared.
+ */
+ public function projectStorage($key);
+
+}