v1.4 Dropbox support

library/Dropbox/ValueStore.php

@@ -0,0 +1,61 @@
+<?php
+namespace Dropbox;
+
+/**
+ * A contract for a class which provides simple get/set/clear access to a single string
+ * value.  {@link ArrayEntryStore} provides an implementation of this for storing a value
+ * in a single array element.
+ *
+ * Example implementation for a Memcache-based backing store:
+ *
+ * <code>
+ * class MemcacheValueStore implements ValueStore
+ * {
+ *     private $key;
+ *     private $memcache;
+ *
+ *     function __construct($memcache, $key)
+ *     {
+ *         $this->memcache = $memcache;
+ *         $this->key = $key;
+ *     }
+ *
+ *     function get()
+ *     {
+ *         $value = $this->memcache->get($this->getKey());
+ *         return $value === false ? null : base64_decode($value);
+ *     }
+ *
+ *     function set($value)
+ *     {
+ *         $this->memcache->set($this->key, base64_encode($value));
+ *     }
+ *
+ *     function clear()
+ *     {
+ *         $this->memcache->delete($this->key);
+ *     }
+ * }
+ * </code>
+ */
+interface ValueStore
+{
+    /**
+     * Returns the entry's current value or <code>null</code> if nothing is set.
+     *
+     * @return string
+     */
+    function get();
+
+    /**
+     * Set the entry to the given value.
+     *
+     * @param string $value
+     */
+    function set($value);
+
+    /**
+     * Remove the value.
+     */
+    function clear();
+}