feat: Implement getSeenUsers to iterate over users

This method uses an iterator.
This is lighter on resources and gives more control to the caller

Signed-off-by: Louis Chemineau <louis@chmn.me>

lib/private/User/Manager.php

@@ -819,4 +819,30 @@ class Manager extends PublicEmitter implements IUserManager {
 	public function getDisplayNameCache(): DisplayNameCache {
 		return $this->displayNameCache;
 	}
+
+	/**
+	 * Gets the list of users sorted by lastLogin, from most recent to least recent
+	 *
+	 * @param int $offset from which offset to fetch
+	 * @return \Iterator<IUser> list of user IDs
+	 * @since 30.0.0
+	 */
+	public function getSeenUsers(int $offset = 0): \Iterator {
+		$limit = 1000;
+
+		do {
+			$userIds = $this->getSeenUserIds($limit, $offset);
+			$offset += $limit;
+
+			foreach ($userIds as $userId) {
+				foreach ($this->backends as $backend) {
+					if ($backend->userExists($userId)) {
+						$user = $this->getUserObject($userId, $backend, false);
+						yield $user;
+						break;
+					}
+				}
+			}
+		} while (count($userIds) === $limit);
+	}
 }

lib/public/IUserManager.php

@@ -221,4 +221,15 @@ interface IUserManager {
 	 * @since 30.0.0
 	 */
 	public function getLastLoggedInUsers(?int $limit = null, int $offset = 0, string $search = ''): array;
+
+	/**
+	 * Gets the list of users.
+	 * An iterator is returned allowing the caller to stop the iteration at any time.
+	 * The offset argument allows the caller to continue the iteration at a specific offset.
+	 *
+	 * @param int $offset from which offset to fetch
+	 * @return \Iterator<IUser> list of IUser object
+	 * @since 32.0.0
+	 */
+	public function getSeenUsers(int $offset = 0): \Iterator;
 }