From 83e7fc32ce5d9a3a96320a88517874b82c6d8ffd Sat, 7 Jan 2012 11:18:35 +0100
From: Bram Goffings <bramgoffings@gmail.com>
Date: Sat, 7 Jan 2012 11:18:23 +0100
Subject: [PATCH] cache psr-0



diff --git a/core/includes/Drupal/Cache/CacheBackendInterface.php b/core/includes/Drupal/Cache/CacheBackendInterface.php
new file mode 100644
index 0000000..2296e2e
--- /dev/null
+++ b/core/includes/Drupal/Cache/CacheBackendInterface.php
@@ -0,0 +1,153 @@
+<?php
+
+/**
+ * @file
+ * Definition of CacheBackendInterface.
+ */
+
+namespace Drupal\Cache;
+
+/**
+ * Defines an interface for cache implementations.
+ *
+ * All cache implementations have to implement this interface.
+ * DrupalDatabaseCache provides the default implementation, which can be
+ * consulted as an example.
+ *
+ * To make Drupal use your implementation for a certain cache bin, you have to
+ * set a variable with the name of the cache bin as its key and the name of
+ * your class as its value. For example, if your implementation of
+ * DrupalCacheInterface was called MyCustomCache, the following line would make
+ * Drupal use it for the 'cache_page' bin:
+ * @code
+ *  variable_set('cache_class_cache_page', 'MyCustomCache');
+ * @endcode
+ *
+ * Additionally, you can register your cache implementation to be used by
+ * default for all cache bins by setting the variable 'cache_default_class' to
+ * the name of your implementation of the DrupalCacheInterface, e.g.
+ * @code
+ *  variable_set('cache_default_class', 'MyCustomCache');
+ * @endcode
+ *
+ * To implement a completely custom cache bin, use the same variable format:
+ * @code
+ *  variable_set('cache_class_custom_bin', 'MyCustomCache');
+ * @endcode
+ * To access your custom cache bin, specify the name of the bin when storing
+ * or retrieving cached data:
+ * @code
+ *  cache_set($cid, $data, 'custom_bin', $expire);
+ *  cache_get($cid, 'custom_bin');
+ * @endcode
+ *
+ * @see cache()
+ * @see DrupalDatabaseCache
+ */
+interface CacheBackendInterface {
+
+  /**
+   * Constructs a new cache backend.
+   *
+   * @param $bin
+   *   The cache bin for which the object is created.
+   */
+  function __construct($bin);
+
+  /**
+   * Returns data from the persistent cache.
+   *
+   * Data may be stored as either plain text or as serialized data. cache_get()
+   * will automatically return unserialized objects and arrays.
+   *
+   * @param $cid
+   *   The cache ID of the data to retrieve.
+   *
+   * @return
+   *   The cache or FALSE on failure.
+   */
+  function get($cid);
+
+  /**
+   * Returns data from the persistent cache when given an array of cache IDs.
+   *
+   * @param $cids
+   *   An array of cache IDs for the data to retrieve. This is passed by
+   *   reference, and will have the IDs successfully returned from cache
+   *   removed.
+   *
+   * @return
+   *   An array of the items successfully returned from cache indexed by cid.
+   */
+  function getMultiple(&$cids);
+
+  /**
+   * Stores data in the persistent cache.
+   *
+   * @param $cid
+   *   The cache ID of the data to store.
+   * @param $data
+   *   The data to store in the cache. Complex data types will be automatically
+   *   serialized before insertion.
+   *   Strings will be stored as plain text and not serialized.
+   * @param $expire
+   *   One of the following values:
+   *   - CACHE_PERMANENT: Indicates that the item should never be removed unless
+   *     explicitly told to using cache_clear_all() with a cache ID.
+   *   - CACHE_TEMPORARY: Indicates that the item should be removed at the next
+   *     general cache wipe.
+   *   - A Unix timestamp: Indicates that the item should be kept at least until
+   *     the given time, after which it behaves like CACHE_TEMPORARY.
+   */
+  function set($cid, $data, $expire = CACHE_PERMANENT);
+
+  /**
+   * Deletes an item from the cache.
+   *
+   * @param $cid
+   *    The cache ID to delete.
+   */
+  function delete($cid);
+
+  /**
+   * Deletes multiple items from the cache.
+   *
+   * @param $cids
+   *   An array of $cids to delete.
+   */
+  function deleteMultiple(Array $cids);
+
+  /**
+   * Deletes items from the cache using a wildcard prefix.
+   *
+   * @param $prefix
+   *   A wildcard prefix.
+   */
+  function deletePrefix($prefix);
+
+  /**
+   * Flushes all cache items in a bin.
+   */
+  function flush();
+
+  /**
+   * Expires temporary items from the cache.
+   */
+  function expire();
+
+  /**
+   * Performs garbage collection on a cache bin.
+   */
+  function garbageCollection();
+
+  /**
+   * Checks if a cache bin is empty.
+   *
+   * A cache bin is considered empty if it does not contain any valid data for
+   * any cache ID.
+   *
+   * @return
+   *   TRUE if the cache bin specified is empty.
+   */
+  function isEmpty();
+}
diff --git a/core/includes/Drupal/Cache/DatabaseBackend.php b/core/includes/Drupal/Cache/DatabaseBackend.php
new file mode 100644
index 0000000..e38a6ba
--- /dev/null
+++ b/core/includes/Drupal/Cache/DatabaseBackend.php
@@ -0,0 +1,250 @@
+<?php
+
+/**
+ * @file
+ * Definition of DatabaseBackend.
+ */
+
+namespace Drupal\Cache;
+
+use Exception;
+
+/**
+ * Defines a default cache implementation.
+ *
+ * This is Drupal's default cache implementation. It uses the database to store
+ * cached data. Each cache bin corresponds to a database table by the same name.
+ */
+class DatabaseBackend implements CacheBackendInterface {
+
+  /**
+   * @var string
+   */
+  protected $bin;
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::__construct().
+   */
+  function __construct($bin) {
+    // All cache tables should be prefixed with 'cache_', except for the
+    // default 'cache' bin.
+    if ($bin != 'cache') {
+      $bin = 'cache_' . $bin;
+    }
+    $this->bin = $bin;
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::get().
+   */
+  function get($cid) {
+    $cids = array($cid);
+    $cache = $this->getMultiple($cids);
+    return reset($cache);
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::getMultiple().
+   */
+  function getMultiple(&$cids) {
+    try {
+      // Garbage collection necessary when enforcing a minimum cache lifetime.
+      $this->garbageCollection($this->bin);
+
+      // When serving cached pages, the overhead of using db_select() was found
+      // to add around 30% overhead to the request. Since $this->bin is a
+      // variable, this means the call to db_query() here uses a concatenated
+      // string. This is highly discouraged under any other circumstances, and
+      // is used here only due to the performance overhead we would incur
+      // otherwise. When serving an uncached page, the overhead of using
+      // db_select() is a much smaller proportion of the request.
+      $result = db_query('SELECT cid, data, created, expire, serialized FROM {' . db_escape_table($this->bin) . '} WHERE cid IN (:cids)', array(':cids' => $cids));
+      $cache = array();
+      foreach ($result as $item) {
+        $item = $this->prepareItem($item);
+        if ($item) {
+          $cache[$item->cid] = $item;
+        }
+      }
+      $cids = array_diff($cids, array_keys($cache));
+      return $cache;
+    }
+    catch (Exception $e) {
+      // If the database is never going to be available, cache requests should
+      // return FALSE in order to allow exception handling to occur.
+      return array();
+    }
+  }
+
+  /**
+   * Prepares a cached item.
+   *
+   * Checks that items are either permanent or did not expire, and unserializes
+   * data as appropriate.
+   *
+   * @param stdClass $cache
+   *   An item loaded from cache_get() or cache_get_multiple().
+   *
+   * @return mixed
+   *   The item with data unserialized as appropriate or FALSE if there is no
+   *   valid item to load.
+   */
+  protected function prepareItem($cache) {
+    global $user;
+
+    if (!isset($cache->data)) {
+      return FALSE;
+    }
+    // If enforcing a minimum cache lifetime, validate that the data is
+    // currently valid for this user before we return it by making sure the cache
+    // entry was created before the timestamp in the current session's cache
+    // timer. The cache variable is loaded into the $user object by
+    // _drupal_session_read() in session.inc. If the data is permanent or we're
+    // not enforcing a minimum cache lifetime always return the cached data.
+    if ($cache->expire != CACHE_PERMANENT && variable_get('cache_lifetime', 0) && $user->cache > $cache->created) {
+      // This cache data is too old and thus not valid for us, ignore it.
+      return FALSE;
+    }
+
+    if ($cache->serialized) {
+      $cache->data = unserialize($cache->data);
+    }
+
+    return $cache;
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::set().
+   */
+  function set($cid, $data, $expire = CACHE_PERMANENT) {
+    $fields = array(
+      'serialized' => 0,
+      'created' => REQUEST_TIME,
+      'expire' => $expire,
+    );
+    if (!is_string($data)) {
+      $fields['data'] = serialize($data);
+      $fields['serialized'] = 1;
+    }
+    else {
+      $fields['data'] = $data;
+      $fields['serialized'] = 0;
+    }
+
+    try {
+      db_merge($this->bin)
+        ->key(array('cid' => $cid))
+        ->fields($fields)
+        ->execute();
+    }
+    catch (Exception $e) {
+      // The database may not be available, so we'll ignore cache_set requests.
+    }
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::delete().
+   */
+  function delete($cid) {
+    db_delete($this->bin)
+      ->condition('cid', $cid)
+      ->execute();
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::deleteMultiple().
+   */
+  function deleteMultiple(Array $cids) {
+    // Delete in chunks when a large array is passed.
+    do {
+      db_delete($this->bin)
+        ->condition('cid', array_splice($cids, 0, 1000), 'IN')
+        ->execute();
+    }
+    while (count($cids));
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::deletePrefix().
+   */
+  function deletePrefix($prefix) {
+    db_delete($this->bin)
+      ->condition('cid', db_like($prefix) . '%', 'LIKE')
+      ->execute();
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::flush().
+   */
+  function flush() {
+    db_truncate($this->bin)->execute();
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::expire().
+   */
+  function expire() {
+    if (variable_get('cache_lifetime', 0)) {
+      // We store the time in the current user's $user->cache variable which
+      // will be saved into the sessions bin by _drupal_session_write(). We then
+      // simulate that the cache was flushed for this user by not returning
+      // cached data that was cached before the timestamp.
+      $GLOBALS['user']->cache = REQUEST_TIME;
+
+      $cache_flush = variable_get('cache_flush_' . $this->bin, 0);
+      if ($cache_flush == 0) {
+        // This is the first request to clear the cache, start a timer.
+        variable_set('cache_flush_' . $this->bin, REQUEST_TIME);
+      }
+      elseif (REQUEST_TIME > ($cache_flush + variable_get('cache_lifetime', 0))) {
+        // Clear the cache for everyone; cache_lifetime seconds have passed
+        // since the first request to clear the cache.
+        db_delete($this->bin)
+          ->condition('expire', CACHE_PERMANENT, '<>')
+          ->condition('expire', REQUEST_TIME, '<')
+          ->execute();
+        variable_set('cache_flush_' . $this->bin, 0);
+      }
+    }
+    else {
+      // No minimum cache lifetime, flush all temporary cache entries now.
+      db_delete($this->bin)
+        ->condition('expire', CACHE_PERMANENT, '<>')
+        ->condition('expire', REQUEST_TIME, '<')
+        ->execute();
+    }
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::garbageCollection().
+   */
+  function garbageCollection() {
+    global $user;
+
+    // When cache lifetime is in force, avoid running garbage collection too
+    // often since this will remove temporary cache items indiscriminately.
+    $cache_flush = variable_get('cache_flush_' . $this->bin, 0);
+    if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= REQUEST_TIME)) {
+      // Reset the variable immediately to prevent a meltdown in heavy load situations.
+      variable_set('cache_flush_' . $this->bin, 0);
+      // Time to flush old cache data
+      db_delete($this->bin)
+        ->condition('expire', CACHE_PERMANENT, '<>')
+        ->condition('expire', $cache_flush, '<=')
+        ->execute();
+    }
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::isEmpty().
+   */
+  function isEmpty() {
+    $this->garbageCollection();
+    $query = db_select($this->bin);
+    $query->addExpression('1');
+    $result = $query->range(0, 1)
+      ->execute()
+      ->fetchField();
+    return empty($result);
+  }
+}
diff --git a/core/includes/Drupal/Cache/InstallBackend.php b/core/includes/Drupal/Cache/InstallBackend.php
new file mode 100644
index 0000000..6f13489
--- /dev/null
+++ b/core/includes/Drupal/Cache/InstallBackend.php
@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * @file
+ * Definition of InstallBackend.
+ */
+
+namespace Drupal\Cache;
+
+use Exception;
+
+/**
+ * Defines a stub cache implementation to be used during installation.
+ *
+ * The stub implementation is needed when database access is not yet available.
+ * Because Drupal's caching system never requires that cached data be present,
+ * these stub functions can short-circuit the process and sidestep the need for
+ * any persistent storage. Obviously, using this cache implementation during
+ * normal operations would have a negative impact on performance.
+ *
+ * If there is a database cache, this backend will attempt to clear it whenever
+ * possible. The reason for doing this is that the database cache can accumulate
+ * data during installation due to any full bootstraps that may occur at the
+ * same time (for example, Ajax requests triggered by the installer). If we
+ * didn't try to clear it whenever one of the delete function are called, the
+ * data in the cache would become stale; for example, the installer sometimes
+ * calls variable_set(), which updates the {variable} table and then clears the
+ * cache to make sure that the next page request picks up the new value.
+ * Not actually clearing the cache here therefore leads old variables to be
+ * loaded on the first page requests after installation, which can cause
+ * subtle bugs, some of which would not be fixed unless the site
+ * administrator cleared the cache manually.
+ */
+class InstallBackend extends DatabaseBackend {
+
+  /**
+   * Overrides Drupal\Cache\DatabaseBackend::get().
+   */
+  function get($cid) {
+    return FALSE;
+  }
+
+  /**
+   * Overrides Drupal\Cache\DatabaseBackend::getMultiple().
+   */
+  function getMultiple(&$cids) {
+    return array();
+  }
+
+  /**
+   * Overrides Drupal\Cache\DatabaseBackend::set().
+   */
+  function set($cid, $data, $expire = CACHE_PERMANENT) {}
+
+  /**
+   * Implements Drupal\Cache\DatabaseBackend::delete().
+   */
+  function delete($cid) {
+    try {
+      if (class_exists('Database')) {
+        parent::delete($cid);
+      }
+    }
+    catch (Exception $e) {}
+  }
+
+  /**
+   * Implements Drupal\Cache\DatabaseBackend::deleteMultiple().
+   */
+  function deleteMultiple(array $cids) {
+    try {
+      if (class_exists('Database')) {
+        parent::deleteMultiple($cids);
+      }
+    }
+    catch (Exception $e) {}
+  }
+
+  /**
+   * Implements Drupal\Cache\DatabaseBackend::deletePrefix().
+   */
+  function deletePrefix($prefix) {
+    try {
+      if (class_exists('Database')) {
+        parent::deletePrefix($prefix);
+      }
+    }
+    catch (Exception $e) {}
+  }
+
+  /**
+   * Implements Drupal\Cache\DatabaseBackend::flush().
+   */
+  function flush() {
+    try {
+      if (class_exists('Database')) {
+        parent::flush();
+      }
+    }
+    catch (Exception $e) {}
+  }
+
+  /**
+   * Overrides Drupal\Cache\DatabaseBackend::isEmpty().
+   */
+  function isEmpty() {
+    return TRUE;
+  }
+}
diff --git a/core/includes/Drupal/Cache/NullBackend.php b/core/includes/Drupal/Cache/NullBackend.php
new file mode 100644
index 0000000..0a20b18
--- /dev/null
+++ b/core/includes/Drupal/Cache/NullBackend.php
@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @file
+ * Definition of NullBackend.
+ */
+
+namespace Drupal\Cache;
+
+/**
+ * Defines a stub cache implementation.
+ *
+ * The stub implementation is needed when database access is not yet available.
+ * Because Drupal's caching system never requires that cached data be present,
+ * these stub functions can short-circuit the process and sidestep the need for
+ * any persistent storage. Using this cache implementation during normal
+ * operations would have a negative impact on performance.
+ *
+ * This also can be used for testing purposes.
+ */
+class NullBackend implements CacheBackendInterface {
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::__construct().
+   */
+  function __construct($bin) {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::get().
+   */
+  function get($cid) {
+    return FALSE;
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::getMultiple().
+   */
+  function getMultiple(&$cids) {
+    return array();
+  }
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::set().
+   */
+  function set($cid, $data, $expire = CACHE_PERMANENT) {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::delete().
+   */
+  function delete($cid) {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::deleteMultiple().
+   */
+  function deleteMultiple(array $cids) {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::deletePrefix().
+   */
+  function deletePrefix($prefix) {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::flush().
+   */
+  function flush() {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::expire().
+   */
+  function expire() {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::garbageCollection().
+   */
+  function garbageCollection() {}
+
+  /**
+   * Implements Drupal\Cache\CacheBackendInterface::isEmpty().
+   */
+  function isEmpty() {
+    return TRUE;
+  }
+}
diff --git a/core/includes/cache-install.inc b/core/includes/cache-install.inc
deleted file mode 100644
index ec46ae0..0000000
--- a/core/includes/cache-install.inc
+++ /dev/null
@@ -1,87 +0,0 @@
-<?php
-
-/**
- * @file
- * Provides a stub cache implementation to be used during installation.
- */
-
-/**
- * Defines a stub cache implementation to be used during installation.
- *
- * The stub implementation is needed when database access is not yet available.
- * Because Drupal's caching system never requires that cached data be present,
- * these stub functions can short-circuit the process and sidestep the need for
- * any persistent storage. Obviously, using this cache implementation during
- * normal operations would have a negative impact on performance.
- */
-class DrupalFakeCache extends DrupalDatabaseCache implements DrupalCacheInterface {
-
-  /**
-   * Overrides DrupalDatabaseCache::get().
-   */
-  function get($cid) {
-    return FALSE;
-  }
-
-  /**
-   * Overrides DrupalDatabaseCache::getMultiple().
-   */
-  function getMultiple(&$cids) {
-    return array();
-  }
-
-  /**
-   * Overrides DrupalDatabaseCache::set().
-   */
-  function set($cid, $data, $expire = CACHE_PERMANENT) {
-  }
-
-  /**
-   * Implements DrupalCacheInterface::deletePrefix().
-   */
-  function deletePrefix($cid) {
-    try {
-      if (class_exists('Database')) {
-        parent::deletePrefix($cid);
-      }
-    }
-    catch (Exception $e) {
-    }
-  }
-
-  /**
-   * Overrides DrupalDatabaseCache::clear().
-   */
-  function clear($cid = NULL, $wildcard = FALSE) {
-    // If there is a database cache, attempt to clear it whenever possible. The
-    // reason for doing this is that the database cache can accumulate data
-    // during installation due to any full bootstraps that may occur at the
-    // same time (for example, Ajax requests triggered by the installer). If we
-    // didn't try to clear it whenever this function is called, the data in the
-    // cache would become stale; for example, the installer sometimes calls
-    // variable_set(), which updates the {variable} table and then clears the
-    // cache to make sure that the next page request picks up the new value.
-    // Not actually clearing the cache here therefore leads old variables to be
-    // loaded on the first page requests after installation, which can cause
-    // subtle bugs, some of which would not be fixed unless the site
-    // administrator cleared the cache manually.
-    try {
-      if (class_exists('Database')) {
-        parent::clear($cid, $wildcard);
-      }
-    }
-    // If the attempt at clearing the cache causes an error, that means that
-    // either the database connection is not set up yet or the relevant cache
-    // table in the database has not yet been created, so we can safely do
-    // nothing here.
-    catch (Exception $e) {
-    }
-  }
-
-  /**
-   * Overrides DrupalDatabaseCache::isEmpty().
-   */
-  function isEmpty() {
-    return TRUE;
-  }
-}
diff --git a/core/includes/cache.inc b/core/includes/cache.inc
index e8c7477..bf06522 100644
--- a/core/includes/cache.inc
+++ b/core/includes/cache.inc
@@ -8,18 +8,20 @@
 /**
  * Instantiates and statically caches the correct class for a cache bin.
  *
- * By default, this returns an instance of the DrupalDatabaseCache class.
- * Classes implementing DrupalCacheInterface can register themselves both as a
- * default implementation and for specific bins.
+ * By default, this returns an instance of the Drupal\Cache\DatabaseBackend
+ * class.
+ *
+ * Classes implementing Drupal\Cache\CacheBackendInterface can register themselves
+ * both as a default implementation and for specific bins.
  *
  * @param $bin
  *   The cache bin for which the cache object should be returned, defaults to
  *   'cache'.
  *
- * @return DrupalCacheInterface
+ * @return Drupal\Cache\CacheBackendInterface
  *   The cache object associated with the specified bin.
  *
- * @see DrupalCacheInterface
+ * @see Drupal\Cache\CacheBackendInterface
  */
 function cache($bin = 'cache') {
   // Temporary backwards compatibiltiy layer, allow old style prefixed cache
@@ -32,7 +34,7 @@
   if (!isset($cache_objects[$bin])) {
     $class = variable_get('cache_class_' . $bin);
     if (!isset($class)) {
-      $class = variable_get('cache_default_class', 'DrupalDatabaseCache');
+      $class = variable_get('cache_default_class', 'Drupal\\Cache\\DatabaseBackend');
     }
     $cache_objects[$bin] = new $class($bin);
   }
@@ -53,460 +55,4 @@
     cache('block')->expire();
   }
   cache('page')->expire();
-}
-
-/**
- * Defines an interface for cache implementations.
- *
- * All cache implementations have to implement this interface.
- * DrupalDatabaseCache provides the default implementation, which can be
- * consulted as an example.
- *
- * To make Drupal use your implementation for a certain cache bin, you have to
- * set a variable with the name of the cache bin as its key and the name of
- * your class as its value. For example, if your implementation of
- * DrupalCacheInterface was called MyCustomCache, the following line would make
- * Drupal use it for the 'cache_page' bin:
- * @code
- *  variable_set('cache_class_cache_page', 'MyCustomCache');
- * @endcode
- *
- * Additionally, you can register your cache implementation to be used by
- * default for all cache bins by setting the variable 'cache_default_class' to
- * the name of your implementation of the DrupalCacheInterface, e.g.
- * @code
- *  variable_set('cache_default_class', 'MyCustomCache');
- * @endcode
- *
- * To implement a completely custom cache bin, use the same variable format:
- * @code
- *  variable_set('cache_class_custom_bin', 'MyCustomCache');
- * @endcode
- * To access your custom cache bin, specify the name of the bin when storing
- * or retrieving cached data:
- * @code
- *  cache_set($cid, $data, 'custom_bin', $expire);
- *  cache_get($cid, 'custom_bin');
- * @endcode
- *
- * @see cache()
- * @see DrupalDatabaseCache
- */
-interface DrupalCacheInterface {
-  /**
-   * Constructs a new cache interface.
-   *
-   * @param $bin
-   *   The cache bin for which the object is created.
-   */
-  function __construct($bin);
-
-  /**
-   * Returns data from the persistent cache.
-   *
-   * Data may be stored as either plain text or as serialized data. cache_get()
-   * will automatically return unserialized objects and arrays.
-   *
-   * @param $cid
-   *   The cache ID of the data to retrieve.
-   *
-   * @return
-   *   The cache or FALSE on failure.
-   */
-  function get($cid);
-
-  /**
-   * Returns data from the persistent cache when given an array of cache IDs.
-   *
-   * @param $cids
-   *   An array of cache IDs for the data to retrieve. This is passed by
-   *   reference, and will have the IDs successfully returned from cache
-   *   removed.
-   *
-   * @return
-   *   An array of the items successfully returned from cache indexed by cid.
-   */
-   function getMultiple(&$cids);
-
-  /**
-   * Stores data in the persistent cache.
-   *
-   * @param $cid
-   *   The cache ID of the data to store.
-   * @param $data
-   *   The data to store in the cache. Complex data types will be automatically
-   *   serialized before insertion.
-   *   Strings will be stored as plain text and not serialized.
-   * @param $expire
-   *   One of the following values:
-   *   - CACHE_PERMANENT: Indicates that the item should never be removed unless
-   *     explicitly told to using cache_clear_all() with a cache ID.
-   *   - CACHE_TEMPORARY: Indicates that the item should be removed at the next
-   *     general cache wipe.
-   *   - A Unix timestamp: Indicates that the item should be kept at least until
-   *     the given time, after which it behaves like CACHE_TEMPORARY.
-   */
-  function set($cid, $data, $expire = CACHE_PERMANENT);
-
-  /**
-   * Deletes an item from the cache.
-   *
-   * @param $cid
-   *    The cache ID to delete.
-   */
-  function delete($cid);
-
-  /**
-   * Deletes multiple items from the cache.
-   *
-   * @param $cids
-   *   An array of $cids to delete.
-   */
-  function deleteMultiple(Array $cids);
-
-  /**
-   * Deletes items from the cache using a wildcard prefix.
-   *
-   * @param $prefix
-   *   A wildcard prefix.
-   */
-  function deletePrefix($prefix);
-
-  /**
-   * Flushes all cache items in a bin.
-   */
-  function flush();
-
-  /**
-   * Expires temporary items from the cache.
-   */
-  function expire();
-
-  /**
-   * Performs garbage collection on a cache bin.
-   */
-  function garbageCollection();
-
-  /**
-   * Checks if a cache bin is empty.
-   *
-   * A cache bin is considered empty if it does not contain any valid data for
-   * any cache ID.
-   *
-   * @return
-   *   TRUE if the cache bin specified is empty.
-   */
-  function isEmpty();
-}
-
-/**
- * Defines a stub cache implementation.
- *
- * The stub implementation is needed when database access is not yet available.
- * Because Drupal's caching system never requires that cached data be present,
- * these stub functions can short-circuit the process and sidestep the need for
- * any persistent storage. Using this cache implementation during normal
- * operations would have a negative impact on performance.
- *
- * This also can be used for testing purposes.
- */
-class DrupalNullCache implements DrupalCacheInterface {
-
-  /**
-   * Constructs a DrupalNullCache object.
-   */
-  function __construct($bin) {}
-
-  /**
-   * Implements DrupalCacheInterface::get().
-   */
-  function get($cid) {
-    return FALSE;
-  }
-
-  /**
-   * Implements DrupalCacheInterface::getMultiple().
-   */
-  function getMultiple(&$cids) {
-    return array();
-  }
-
-  /**
-   * Implements DrupalCacheInterface::set().
-   */
-  function set($cid, $data, $expire = CACHE_PERMANENT) {}
-
-  /**
-   * Implements DrupalCacheInterface::delete().
-   */
-  function delete($cid) {}
-
-  /**
-   * Implements DrupalCacheInterface::deleteMultiple().
-   */
-  function deleteMultiple(array $cids) {}
-
-  /**
-   * Implements DrupalCacheInterface::deletePrefix().
-   */
-  function deletePrefix($prefix) {}
-
-  /**
-   * Implements DrupalCacheInterface::flush().
-   */
-  function flush() {}
-
-  /**
-   * Implements DrupalCacheInterface::expire().
-   */
-  function expire() {}
-
-  /**
-   * Implements DrupalCacheInterface::garbageCollection().
-   */
-  function garbageCollection() {}
-
-  /**
-   * Implements DrupalCacheInterface::isEmpty().
-   */
-  function isEmpty() {
-    return TRUE;
-  }
-}
-
-/**
- * Defines a default cache implementation.
- *
- * This is Drupal's default cache implementation. It uses the database to store
- * cached data. Each cache bin corresponds to a database table by the same name.
- */
-class DrupalDatabaseCache implements DrupalCacheInterface {
-  protected $bin;
-
-  /**
-   * Constructs a new DrupalDatabaseCache object.
-   */
-  function __construct($bin) {
-    // All cache tables should be prefixed with 'cache_', except for the
-    // default 'cache' bin.
-    if ($bin != 'cache') {
-      $bin = 'cache_' . $bin;
-    }
-    $this->bin = $bin;
-  }
-
-  /**
-   * Implements DrupalCacheInterface::get().
-   */
-  function get($cid) {
-    $cids = array($cid);
-    $cache = $this->getMultiple($cids);
-    return reset($cache);
-  }
-
-  /**
-   * Implements DrupalCacheInterface::getMultiple().
-   */
-  function getMultiple(&$cids) {
-    try {
-      // Garbage collection necessary when enforcing a minimum cache lifetime.
-      $this->garbageCollection($this->bin);
-
-      // When serving cached pages, the overhead of using db_select() was found
-      // to add around 30% overhead to the request. Since $this->bin is a
-      // variable, this means the call to db_query() here uses a concatenated
-      // string. This is highly discouraged under any other circumstances, and
-      // is used here only due to the performance overhead we would incur
-      // otherwise. When serving an uncached page, the overhead of using
-      // db_select() is a much smaller proportion of the request.
-      $result = db_query('SELECT cid, data, created, expire, serialized FROM {' . db_escape_table($this->bin) . '} WHERE cid IN (:cids)', array(':cids' => $cids));
-      $cache = array();
-      foreach ($result as $item) {
-        $item = $this->prepareItem($item);
-        if ($item) {
-          $cache[$item->cid] = $item;
-        }
-      }
-      $cids = array_diff($cids, array_keys($cache));
-      return $cache;
-    }
-    catch (Exception $e) {
-      // If the database is never going to be available, cache requests should
-      // return FALSE in order to allow exception handling to occur.
-      return array();
-    }
-  }
-
-  /**
-   * Prepares a cached item.
-   *
-   * Checks that items are either permanent or did not expire, and unserializes
-   * data as appropriate.
-   *
-   * @param $cache
-   *   An item loaded from cache_get() or cache_get_multiple().
-   *
-   * @return
-   *   The item with data unserialized as appropriate or FALSE if there is no
-   *   valid item to load.
-   */
-  protected function prepareItem($cache) {
-    global $user;
-
-    if (!isset($cache->data)) {
-      return FALSE;
-    }
-    // If enforcing a minimum cache lifetime, validate that the data is
-    // currently valid for this user before we return it by making sure the cache
-    // entry was created before the timestamp in the current session's cache
-    // timer. The cache variable is loaded into the $user object by
-    // _drupal_session_read() in session.inc. If the data is permanent or we're
-    // not enforcing a minimum cache lifetime always return the cached data.
-    if ($cache->expire != CACHE_PERMANENT && variable_get('cache_lifetime', 0) && $user->cache > $cache->created) {
-      // This cache data is too old and thus not valid for us, ignore it.
-      return FALSE;
-    }
-
-    if ($cache->serialized) {
-      $cache->data = unserialize($cache->data);
-    }
-
-    return $cache;
-  }
-
-  /**
-   * Implements DrupalCacheInterface::set().
-   */
-  function set($cid, $data, $expire = CACHE_PERMANENT) {
-    $fields = array(
-      'serialized' => 0,
-      'created' => REQUEST_TIME,
-      'expire' => $expire,
-    );
-    if (!is_string($data)) {
-      $fields['data'] = serialize($data);
-      $fields['serialized'] = 1;
-    }
-    else {
-      $fields['data'] = $data;
-      $fields['serialized'] = 0;
-    }
-
-    try {
-      db_merge($this->bin)
-        ->key(array('cid' => $cid))
-        ->fields($fields)
-        ->execute();
-    }
-    catch (Exception $e) {
-      // The database may not be available, so we'll ignore these calls.
-    }
-  }
-
-  /**
-   * Implements DrupalCacheInterface::delete().
-   */
-  function delete($cid) {
-    db_delete($this->bin)
-      ->condition('cid', $cid)
-      ->execute();
-  }
-
-  /**
-   * Implements DrupalCacheInterface::deleteMultiple().
-   */
-  function deleteMultiple(Array $cids) {
-    // Delete in chunks when a large array is passed.
-    do {
-      db_delete($this->bin)
-        ->condition('cid', array_splice($cids, 0, 1000), 'IN')
-        ->execute();
-    }
-    while (count($cids));
-  }
-
-  /**
-   * Implements DrupalCacheInterface::deletePrefix().
-   */
-  function deletePrefix($prefix) {
-    db_delete($this->bin)
-      ->condition('cid', db_like($prefix) . '%', 'LIKE')
-      ->execute();
-  }
-
-  /**
-   * Implements DrupalCacheInterface::flush().
-   */
-  function flush() {
-    db_truncate($this->bin)->execute();
-  }
-
-  /**
-   * Implements DrupalCacheInterface::expire().
-   */
-  function expire() {
-    if (variable_get('cache_lifetime', 0)) {
-      // We store the time in the current user's $user->cache variable which
-      // will be saved into the sessions bin by _drupal_session_write(). We then
-      // simulate that the cache was flushed for this user by not returning
-      // cached data that was cached before the timestamp.
-      $GLOBALS['user']->cache = REQUEST_TIME;
-
-      $cache_flush = variable_get('cache_flush_' . $this->bin, 0);
-      if ($cache_flush == 0) {
-        // This is the first request to clear the cache; start a timer.
-        variable_set('cache_flush_' . $this->bin, REQUEST_TIME);
-      }
-      elseif (REQUEST_TIME > ($cache_flush + variable_get('cache_lifetime', 0))) {
-        // Clear the cache for everyone; cache_lifetime seconds have passed
-        // since the first request to clear the cache.
-        db_delete($this->bin)
-          ->condition('expire', CACHE_PERMANENT, '<>')
-          ->condition('expire', REQUEST_TIME, '<')
-          ->execute();
-        variable_set('cache_flush_' . $this->bin, 0);
-      }
-    }
-    else {
-      // No minimum cache lifetime; flush all temporary cache entries now.
-      db_delete($this->bin)
-        ->condition('expire', CACHE_PERMANENT, '<>')
-        ->condition('expire', REQUEST_TIME, '<')
-        ->execute();
-    }
-  }
-
-  /**
-   * Implements DrupalCacheInterface::garbageCollection().
-   */
-  function garbageCollection() {
-    global $user;
-
-    // When cache lifetime is in force, avoid running garbage collection too
-    // often since this will remove temporary cache items indiscriminately.
-    $cache_flush = variable_get('cache_flush_' . $this->bin, 0);
-    if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= REQUEST_TIME)) {
-      // Reset the variable immediately to prevent a meltdown in heavy load
-      // situations.
-      variable_set('cache_flush_' . $this->bin, 0);
-      // Time to flush old cache data
-      db_delete($this->bin)
-        ->condition('expire', CACHE_PERMANENT, '<>')
-        ->condition('expire', $cache_flush, '<=')
-        ->execute();
-    }
-  }
-
-  /**
-   * Implements DrupalCacheInterface::isEmpty().
-   */
-  function isEmpty() {
-    $this->garbageCollection();
-    $query = db_select($this->bin);
-    $query->addExpression('1');
-    $result = $query->range(0, 1)
-      ->execute()
-      ->fetchField();
-    return empty($result);
-  }
 }
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index f76606b..089b3cf 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -277,8 +277,7 @@
   // because any data put in the cache during the installer is inherently
   // suspect, due to the fact that Drupal is not fully set up yet.
   require_once DRUPAL_ROOT . '/core/includes/cache.inc';
-  require_once DRUPAL_ROOT . '/core/includes/cache-install.inc';
-  $conf['cache_default_class'] = 'DrupalFakeCache';
+  $conf['cache_default_class'] = 'Drupal\\Cache\\InstallBackend';
 
   // Prepare for themed output. We need to run this at the beginning of the
   // page request to avoid a different theme accidentally getting set. (We also