Add FileCache driver

app/Core/Cache/BaseCache.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace Kanboard\Core\Cache;
+
+/**
+ * Base Class for Cache Drivers
+ *
+ * @package  Kanboard\Core\Cache
+ * @author   Frederic Guillot
+ */
+abstract class BaseCache
+{
+    /**
+     * Store an item in the cache
+     *
+     * @access public
+     * @param  string  $key
+     * @param  string  $value
+     */
+    abstract public function set($key, $value);
+
+    /**
+     * Retrieve an item from the cache by key
+     *
+     * @access public
+     * @param  string  $key
+     * @return mixed            Null when not found, cached value otherwise
+     */
+    abstract public function get($key);
+
+    /**
+     * Remove all items from the cache
+     *
+     * @access public
+     */
+    abstract public function flush();
+
+    /**
+     * Remove an item from the cache
+     *
+     * @access public
+     * @param  string  $key
+     */
+    abstract public function remove($key);
+
+    /**
+     * Proxy cache
+     *
+     * Note: Arguments must be scalar types
+     *
+     * @access public
+     * @param  string    $class        Class instance
+     * @param  string    $method       Container method
+     * @return mixed
+     */
+    public function proxy($class, $method)
+    {
+        $args = func_get_args();
+        array_shift($args);
+
+        $key = 'proxy:'.get_class($class).':'.implode(':', $args);
+        $result = $this->get($key);
+
+        if ($result === null) {
+            $result = call_user_func_array(array($class, $method), array_splice($args, 1));
+            $this->set($key, $result);
+        }
+
+        return $result;
+    }
+}