diff core/modules/user/src/SharedTempStore.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/modules/user/src/SharedTempStore.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,279 @@
+<?php
+
+namespace Drupal\user;
+
+use Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface;
+use Drupal\Core\Lock\LockBackendInterface;
+use Symfony\Component\HttpFoundation\RequestStack;
+
+/**
+ * Stores and retrieves temporary data for a given owner.
+ *
+ * A SharedTempStore can be used to make temporary, non-cache data available
+ * across requests. The data for the SharedTempStore is stored in one key/value
+ * collection. SharedTempStore data expires automatically after a given
+ * timeframe.
+ *
+ * The SharedTempStore is different from a cache, because the data in it is not
+ * yet saved permanently and so it cannot be rebuilt. Typically, the
+ * SharedTempStore might be used to store work in progress that is later saved
+ * permanently elsewhere, e.g. autosave data, multistep forms, or in-progress
+ * changes to complex configuration that are not ready to be saved.
+ *
+ * Each SharedTempStore belongs to a particular owner (e.g. a user, session, or
+ * process). Multiple owners may use the same key/value collection, and the
+ * owner is stored along with the key/value pair.
+ *
+ * Every key is unique within the collection, so the SharedTempStore can check
+ * whether a particular key is already set by a different owner. This is
+ * useful for informing one owner that the data is already in use by another;
+ * for example, to let one user know that another user is in the process of
+ * editing certain data, or even to restrict other users from editing it at
+ * the same time. It is the responsibility of the implementation to decide
+ * when and whether one owner can use or update another owner's data.
+ *
+ * If you want to be able to ensure that the data belongs to the current user,
+ * use \Drupal\user\PrivateTempStore.
+ */
+class SharedTempStore {
+
+  /**
+   * The key/value storage object used for this data.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface
+   */
+  protected $storage;
+
+  /**
+   * The lock object used for this data.
+   *
+   * @var \Drupal\Core\Lock\LockBackendInterface
+   */
+  protected $lockBackend;
+
+  /**
+   * The request stack.
+   *
+   * @var \Symfony\Component\HttpFoundation\RequestStack
+   */
+  protected $requestStack;
+
+  /**
+   * The owner key to store along with the data (e.g. a user or session ID).
+   *
+   * @var mixed
+   */
+  protected $owner;
+
+  /**
+   * The time to live for items in seconds.
+   *
+   * By default, data is stored for one week (604800 seconds) before expiring.
+   *
+   * @var int
+   */
+  protected $expire;
+
+  /**
+   * Constructs a new object for accessing data from a key/value store.
+   *
+   * @param KeyValueStoreExpirableInterface $storage
+   *   The key/value storage object used for this data. Each storage object
+   *   represents a particular collection of data and will contain any number
+   *   of key/value pairs.
+   * @param \Drupal\Core\Lock\LockBackendInterface $lock_backend
+   *   The lock object used for this data.
+   * @param mixed $owner
+   *   The owner key to store along with the data (e.g. a user or session ID).
+   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
+   *   The request stack.
+   * @param int $expire
+   *   The time to live for items, in seconds.
+   */
+  public function __construct(KeyValueStoreExpirableInterface $storage, LockBackendInterface $lock_backend, $owner, RequestStack $request_stack, $expire = 604800) {
+    $this->storage = $storage;
+    $this->lockBackend = $lock_backend;
+    $this->owner = $owner;
+    $this->requestStack = $request_stack;
+    $this->expire = $expire;
+  }
+
+  /**
+   * Retrieves a value from this SharedTempStore for a given key.
+   *
+   * @param string $key
+   *   The key of the data to retrieve.
+   *
+   * @return mixed
+   *   The data associated with the key, or NULL if the key does not exist.
+   */
+  public function get($key) {
+    if ($object = $this->storage->get($key)) {
+      return $object->data;
+    }
+  }
+
+  /**
+   * Retrieves a value from this SharedTempStore for a given key.
+   *
+   * Only returns the value if the value is owned by $this->owner.
+   *
+   * @param string $key
+   *   The key of the data to retrieve.
+   *
+   * @return mixed
+   *   The data associated with the key, or NULL if the key does not exist.
+   */
+  public function getIfOwner($key) {
+    if (($object = $this->storage->get($key)) && ($object->owner == $this->owner)) {
+      return $object->data;
+    }
+  }
+
+  /**
+   * Stores a particular key/value pair only if the key doesn't already exist.
+   *
+   * @param string $key
+   *   The key of the data to check and store.
+   * @param mixed $value
+   *   The data to store.
+   *
+   * @return bool
+   *   TRUE if the data was set, or FALSE if it already existed.
+   */
+  public function setIfNotExists($key, $value) {
+    $value = (object) [
+      'owner' => $this->owner,
+      'data' => $value,
+      'updated' => (int) $this->requestStack->getMasterRequest()->server->get('REQUEST_TIME'),
+    ];
+    return $this->storage->setWithExpireIfNotExists($key, $value, $this->expire);
+  }
+
+  /**
+   * Stores a particular key/value pair in this SharedTempStore.
+   *
+   * Only stores the given key/value pair if it does not exist yet or is owned
+   * by $this->owner.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   * @param mixed $value
+   *   The data to store.
+   *
+   * @return bool
+   *   TRUE if the data was set, or FALSE if it already exists and is not owned
+   *   by $this->user.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock for the backend storage could not be acquired.
+   */
+  public function setIfOwner($key, $value) {
+    if ($this->setIfNotExists($key, $value)) {
+      return TRUE;
+    }
+
+    if (($object = $this->storage->get($key)) && ($object->owner == $this->owner)) {
+      $this->set($key, $value);
+      return TRUE;
+    }
+
+    return FALSE;
+  }
+
+  /**
+   * Stores a particular key/value pair in this SharedTempStore.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   * @param mixed $value
+   *   The data to store.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock for the backend storage could not be acquired.
+   */
+  public function set($key, $value) {
+    if (!$this->lockBackend->acquire($key)) {
+      $this->lockBackend->wait($key);
+      if (!$this->lockBackend->acquire($key)) {
+        throw new TempStoreException("Couldn't acquire lock to update item '$key' in '{$this->storage->getCollectionName()}' temporary storage.");
+      }
+    }
+
+    $value = (object) [
+      'owner' => $this->owner,
+      'data' => $value,
+      'updated' => (int) $this->requestStack->getMasterRequest()->server->get('REQUEST_TIME'),
+    ];
+    $this->storage->setWithExpire($key, $value, $this->expire);
+    $this->lockBackend->release($key);
+  }
+
+  /**
+   * Returns the metadata associated with a particular key/value pair.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   *
+   * @return mixed
+   *   An object with the owner and updated time if the key has a value, or
+   *   NULL otherwise.
+   */
+  public function getMetadata($key) {
+    // Fetch the key/value pair and its metadata.
+    $object = $this->storage->get($key);
+    if ($object) {
+      // Don't keep the data itself in memory.
+      unset($object->data);
+      return $object;
+    }
+  }
+
+  /**
+   * Deletes data from the store for a given key and releases the lock on it.
+   *
+   * @param string $key
+   *   The key of the data to delete.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock for the backend storage could not be acquired.
+   */
+  public function delete($key) {
+    if (!$this->lockBackend->acquire($key)) {
+      $this->lockBackend->wait($key);
+      if (!$this->lockBackend->acquire($key)) {
+        throw new TempStoreException("Couldn't acquire lock to delete item '$key' from {$this->storage->getCollectionName()} temporary storage.");
+      }
+    }
+    $this->storage->delete($key);
+    $this->lockBackend->release($key);
+  }
+
+  /**
+   * Deletes data from the store for a given key and releases the lock on it.
+   *
+   * Only delete the given key if it is owned by $this->owner.
+   *
+   * @param string $key
+   *   The key of the data to delete.
+   *
+   * @return bool
+   *   TRUE if the object was deleted or does not exist, FALSE if it exists but
+   *   is not owned by $this->owner.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock for the backend storage could not be acquired.
+   */
+  public function deleteIfOwner($key) {
+    if (!$object = $this->storage->get($key)) {
+      return TRUE;
+    }
+    elseif ($object->owner == $this->owner) {
+      $this->delete($key);
+      return TRUE;
+    }
+
+    return FALSE;
+  }
+
+}