diff core/lib/Drupal/Core/Session/AccountSwitcher.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Session/AccountSwitcher.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,91 @@
+<?php
+
+namespace Drupal\Core\Session;
+
+/**
+ * An implementation of AccountSwitcherInterface.
+ *
+ * This allows for safe switching of user accounts by ensuring that session
+ * data for one user is not leaked in to others. It also provides a stack that
+ * allows reverting to a previous user after switching.
+ */
+class AccountSwitcher implements AccountSwitcherInterface {
+
+  /**
+   * A stack of previous overridden accounts.
+   *
+   * @var \Drupal\Core\Session\AccountInterface[]
+   */
+  protected $accountStack = [];
+
+  /**
+   * The current user service.
+   *
+   * @var \Drupal\Core\Session\AccountProxyInterface
+   */
+  protected $currentUser = [];
+
+  /**
+   * The write-safe session handler.
+   *
+   * @var \Drupal\Core\Session\WriteSafeSessionHandlerInterface
+   */
+  protected $writeSafeHandler;
+
+  /**
+   * The original state of session saving prior to account switching.
+   *
+   * @var bool
+   */
+  protected $originalSessionSaving;
+
+  /**
+   * Constructs a new AccountSwitcher.
+   *
+   * @param \Drupal\Core\Session\AccountProxyInterface $current_user
+   *   The current user service.
+   * @param \Drupal\Core\Session\WriteSafeSessionHandlerInterface $write_safe_handler
+   *   The write-safe session handler.
+   */
+  public function __construct(AccountProxyInterface $current_user, WriteSafeSessionHandlerInterface $write_safe_handler) {
+    $this->currentUser = $current_user;
+    $this->writeSafeHandler = $write_safe_handler;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function switchTo(AccountInterface $account) {
+    // Prevent session information from being saved and push previous account.
+    if (!isset($this->originalSessionSaving)) {
+      // Ensure that only the first session saving status is saved.
+      $this->originalSessionSaving = $this->writeSafeHandler->isSessionWritable();
+    }
+    $this->writeSafeHandler->setSessionWritable(FALSE);
+    array_push($this->accountStack, $this->currentUser->getAccount());
+    $this->currentUser->setAccount($account);
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function switchBack() {
+    // Restore the previous account from the stack.
+    if (!empty($this->accountStack)) {
+      $this->currentUser->setAccount(array_pop($this->accountStack));
+    }
+    else {
+      throw new \RuntimeException('No more accounts to revert to.');
+    }
+    // Restore original session saving status if all account switches are
+    // reverted.
+    if (empty($this->accountStack)) {
+      if ($this->originalSessionSaving) {
+        $this->writeSafeHandler->setSessionWritable(TRUE);
+      }
+    }
+    return $this;
+  }
+
+}