diff core/lib/Drupal/Core/Cache/ApcuBackend.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Cache/ApcuBackend.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,271 @@
+<?php
+
+namespace Drupal\Core\Cache;
+
+/**
+ * Stores cache items in the Alternative PHP Cache User Cache (APCu).
+ */
+class ApcuBackend implements CacheBackendInterface {
+
+  /**
+   * The name of the cache bin to use.
+   *
+   * @var string
+   */
+  protected $bin;
+
+  /**
+   * Prefix for all keys in the storage that belong to this site.
+   *
+   * @var string
+   */
+  protected $sitePrefix;
+
+  /**
+   * Prefix for all keys in this cache bin.
+   *
+   * Includes the site-specific prefix in $sitePrefix.
+   *
+   * @var string
+   */
+  protected $binPrefix;
+
+  /**
+   * The cache tags checksum provider.
+   *
+   * @var \Drupal\Core\Cache\CacheTagsChecksumInterface
+   */
+  protected $checksumProvider;
+
+  /**
+   * Constructs a new ApcuBackend instance.
+   *
+   * @param string $bin
+   *   The name of the cache bin.
+   * @param string $site_prefix
+   *   The prefix to use for all keys in the storage that belong to this site.
+   * @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
+   *   The cache tags checksum provider.
+   */
+  public function __construct($bin, $site_prefix, CacheTagsChecksumInterface $checksum_provider) {
+    $this->bin = $bin;
+    $this->sitePrefix = $site_prefix;
+    $this->checksumProvider = $checksum_provider;
+    $this->binPrefix = $this->sitePrefix . '::' . $this->bin . '::';
+  }
+
+  /**
+   * Prepends the APCu user variable prefix for this bin to a cache item ID.
+   *
+   * @param string $cid
+   *   The cache item ID to prefix.
+   *
+   * @return string
+   *   The APCu key for the cache item ID.
+   */
+  public function getApcuKey($cid) {
+    return $this->binPrefix . $cid;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function get($cid, $allow_invalid = FALSE) {
+    $cache = apcu_fetch($this->getApcuKey($cid));
+    return $this->prepareItem($cache, $allow_invalid);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getMultiple(&$cids, $allow_invalid = FALSE) {
+    // Translate the requested cache item IDs to APCu keys.
+    $map = [];
+    foreach ($cids as $cid) {
+      $map[$this->getApcuKey($cid)] = $cid;
+    }
+
+    $result = apcu_fetch(array_keys($map));
+    $cache = [];
+    if ($result) {
+      foreach ($result as $key => $item) {
+        $item = $this->prepareItem($item, $allow_invalid);
+        if ($item) {
+          $cache[$map[$key]] = $item;
+        }
+      }
+    }
+    unset($result);
+
+    $cids = array_diff($cids, array_keys($cache));
+    return $cache;
+  }
+
+  /**
+   * Returns all cached items, optionally limited by a cache ID prefix.
+   *
+   * APCu is a memory cache, shared across all server processes. To prevent
+   * cache item clashes with other applications/installations, every cache item
+   * is prefixed with a unique string for this site. Therefore, functions like
+   * apcu_clear_cache() cannot be used, and instead, a list of all cache items
+   * belonging to this application need to be retrieved through this method
+   * instead.
+   *
+   * @param string $prefix
+   *   (optional) A cache ID prefix to limit the result to.
+   *
+   * @return \APCUIterator
+   *   An APCUIterator containing matched items.
+   */
+  protected function getAll($prefix = '') {
+    return $this->getIterator('/^' . preg_quote($this->getApcuKey($prefix), '/') . '/');
+  }
+
+  /**
+   * Prepares a cached item.
+   *
+   * Checks that the item is either permanent or did not expire.
+   *
+   * @param \stdClass $cache
+   *   An item loaded from cache_get() or cache_get_multiple().
+   * @param bool $allow_invalid
+   *   If TRUE, a cache item may be returned even if it is expired or has been
+   *   invalidated. See ::get().
+   *
+   * @return mixed
+   *   The cache item or FALSE if the item expired.
+   */
+  protected function prepareItem($cache, $allow_invalid) {
+    if (!isset($cache->data)) {
+      return FALSE;
+    }
+
+    $cache->tags = $cache->tags ? explode(' ', $cache->tags) : [];
+
+    // Check expire time.
+    $cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
+
+    // Check if invalidateTags() has been called with any of the entry's tags.
+    if (!$this->checksumProvider->isValid($cache->checksum, $cache->tags)) {
+      $cache->valid = FALSE;
+    }
+
+    if (!$allow_invalid && !$cache->valid) {
+      return FALSE;
+    }
+
+    return $cache;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = []) {
+    assert('\Drupal\Component\Assertion\Inspector::assertAllStrings($tags)', 'Cache tags must be strings.');
+    $tags = array_unique($tags);
+    $cache = new \stdClass();
+    $cache->cid = $cid;
+    $cache->created = round(microtime(TRUE), 3);
+    $cache->expire = $expire;
+    $cache->tags = implode(' ', $tags);
+    $cache->checksum = $this->checksumProvider->getCurrentChecksum($tags);
+    // APCu serializes/unserializes any structure itself.
+    $cache->serialized = 0;
+    $cache->data = $data;
+
+    // Expiration is handled by our own prepareItem(), not APCu.
+    apcu_store($this->getApcuKey($cid), $cache);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setMultiple(array $items = []) {
+    foreach ($items as $cid => $item) {
+      $this->set($cid, $item['data'], isset($item['expire']) ? $item['expire'] : CacheBackendInterface::CACHE_PERMANENT, isset($item['tags']) ? $item['tags'] : []);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function delete($cid) {
+    apcu_delete($this->getApcuKey($cid));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteMultiple(array $cids) {
+    apcu_delete(array_map([$this, 'getApcuKey'], $cids));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteAll() {
+    apcu_delete($this->getIterator('/^' . preg_quote($this->binPrefix, '/') . '/'));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function garbageCollection() {
+    // APCu performs garbage collection automatically.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function removeBin() {
+    apcu_delete($this->getIterator('/^' . preg_quote($this->binPrefix, '/') . '/'));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function invalidate($cid) {
+    $this->invalidateMultiple([$cid]);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function invalidateMultiple(array $cids) {
+    foreach ($this->getMultiple($cids) as $cache) {
+      $this->set($cache->cid, $cache, REQUEST_TIME - 1);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function invalidateAll() {
+    foreach ($this->getAll() as $data) {
+      $cid = str_replace($this->binPrefix, '', $data['key']);
+      $this->set($cid, $data['value'], REQUEST_TIME - 1);
+    }
+  }
+
+  /**
+   * Instantiates and returns the APCUIterator class.
+   *
+   * @param mixed $search
+   *   A PCRE regular expression that matches against APC key names, either as a
+   *   string for a single regular expression, or as an array of regular
+   *   expressions. Or, optionally pass in NULL to skip the search.
+   * @param int $format
+   *   The desired format, as configured with one or more of the APC_ITER_*
+   *   constants.
+   * @param int $chunk_size
+   *   The chunk size. Must be a value greater than 0. The default value is 100.
+   * @param int $list
+   *   The type to list. Either pass in APC_LIST_ACTIVE or APC_LIST_DELETED.
+   *
+   * @return \APCUIterator
+   */
+  protected function getIterator($search = NULL, $format = APC_ITER_ALL, $chunk_size = 100, $list = APC_LIST_ACTIVE) {
+    return new \APCUIterator($search, $format, $chunk_size, $list);
+  }
+
+}