made Stud.IP cache compatible with PSR-6, re #3701

Merge request studip/studip!2570

1 files changed, 208 insertions, 0 deletions

diff --git a/lib/classes/cache/Cache.class.php b/lib/classes/cache/Cache.class.php
new file mode 100644
index 0000000..366945d
--- /dev/null
+++ b/lib/classes/cache/Cache.class.php
@@ -0,0 +1,208 @@
+<?php
+
+namespace Studip\Cache;
+
+use Psr\Cache\CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * An abstract class which has to be extended by instances returned from
+ * \Studip\Cache\Factory#getCache
+ *
+ * @author     Marco Diedrich (mdiedric@uos)
+ * @author     Marcus Lunzenauer (mlunzena@uos.de)
+ * @author     Moritz Strohm <strohm@data-quest.de>
+ * @copyright  (c) Authors
+ * @since      1.6
+ * @license    GPL2 or any later version
+ */
+abstract class Cache implements CacheItemPoolInterface
+{
+    const DEFAULT_EXPIRATION = 12 * 60 * 60; // 12 hours
+
+    /**
+     * @return string A translateable display name for this cache class.
+     */
+    abstract public static function getDisplayName(): string;
+
+    /**
+     * Get some statistics from cache, like number of entries, hit rate or
+     * whatever the underlying cache provides.
+     * Results are returned in form of an array like
+     *      "[
+     *          [
+     *              'name' => <displayable name>
+     *              'value' => <value of the current stat>
+     *          ]
+     *      ]"
+     *
+     * @return array
+     */
+    abstract public function getStats(): array;
+
+    /**
+     * Return the Vue component name and props that handle configuration.
+     * The associative array is of the form
+     *  [
+     *      'component' => <Vue component name>,
+     *      'props' => <Properties for component>
+     *  ]
+     *
+     * @return array
+     */
+    abstract public static function getConfig(): array;
+
+    /**
+     * Expire item from the cache.
+     *
+     * Example:
+     *
+     *   # expires foo
+     *   $cache->expire('foo');
+     *
+     * @param string $arg a single key
+     */
+    abstract public function expire($arg);
+
+    /**
+     * Expire all items from the cache.
+     */
+    abstract public function flush();
+
+    /**
+     * @see CacheItemPoolInterface::getItem
+     */
+    abstract public function getItem($key);
+
+    /**
+     * @see CacheItemPoolInterface::hasItem
+     */
+    abstract public function hasItem($key);
+
+    /**
+     * @var array An array of deferred items that shall be saved only
+     * when commit() is called. This is only used in PSR-6 cache methods.
+     */
+    protected array $deferred_items = [];
+
+    /**
+     * Retrieve item from the server.
+     *
+     * Example:
+     *
+     *   # reads foo
+     *   $foo = $cache->reads('foo');
+     *
+     * @param string $arg a single key
+     *
+     * @return mixed    the previously stored data if an item with such a key
+     *                  exists on the server or FALSE on failure.
+     *
+     * @deprecated To be removed with Stud.IP 7.0.
+     */
+    public function read($arg)
+    {
+        $item = $this->getItem($arg);
+        if ($item->isHit()) {
+            return $item->get();
+        }
+        return false;
+    }
+
+    /**
+     * Store data at the server.
+     *
+     * @param string $name     the item's key.
+     * @param mixed  $content  the item's content (will be serialized if necessary).
+     * @param int    $expires  the item's expiry time in seconds. Optional, defaults to 12h.
+     *
+     * @return bool     returns TRUE on success or FALSE on failure.
+
+     * @deprecated To be removed with Stud.IP 7.0.
+     */
+    public function write($name, $content, $expires = self::DEFAULT_EXPIRATION)
+    {
+        $item = new Item($name, $content, $expires);
+
+        return $this->save($item);
+    }
+
+    /**
+     * Calculates the expiration by a cache item. If that cannot be determined,
+     * the default expiration period is returned.
+     *
+     * @param Item $item The item from which to get the expiration time.
+     *
+     * @return int The time from now until the expiration in seconds.
+     */
+    public function getExpiration(CacheItemInterface $item) : int
+    {
+        $expiration = self::DEFAULT_EXPIRATION;
+        if ($item instanceof Item) {
+            $expiration = $item->getExpirationInSeconds();
+        }
+        return $expiration;
+    }
+
+    // PSR-6 CacheItemPoolInterface:
+
+    /**
+     * @see CacheItemPoolInterface::getItems
+     */
+    public function getItems(array $keys = [])
+    {
+        $items = [];
+        foreach ($keys as $key) {
+            $item = $this->getItem($key);
+            if ($item instanceof Item) {
+                $items[] = $item;
+            }
+        }
+        return $items;
+    }
+
+    /**
+     * @see CacheItemPoolInterface::clear
+     */
+    public function clear()
+    {
+        $this->deferred_items = [];
+        $this->flush();
+    }
+
+    /**
+     * @see CacheItemPoolInterface::deleteItem
+     */
+    public function deleteItem($key)
+    {
+        $this->expire($key);
+    }
+
+    /**
+     * @see CacheItemPoolInterface::deleteItems
+     */
+    public function deleteItems(array $keys)
+    {
+        foreach ($keys as $key) {
+            $this->expire($key);
+        }
+    }
+
+    /**
+     * @see CacheItemPoolInterface::saveDeferred
+     */
+    public function saveDeferred(CacheItemInterface $item)
+    {
+        $this->deferred_items[] = $item;
+    }
+
+    /**
+     * @see CacheItemPoolInterface::commit
+     */
+    public function commit()
+    {
+        foreach ($this->deferred_items as $item) {
+            $this->save($item);
+        }
+    }
+}