Added touch() and incWithTouch().

Author: dorantor

README.md

@@ -55,6 +55,16 @@ protected function getExpiry()
     // or it could be some logic based on value(s) in $this->item
 }
 ```
+*NB!* Expiry is not updated on inc() call. It's default Memcached
+behaviour. If you need to update expiry use `touch()`, p.ex.:
+```php
+$counter->inc();
+$counter->touch();
+// or
+$counter->incWithTouch();
+```
+Second option is more convenient but you loose control over `touch()`
+success/fail.
 
 
 

src/AbstractCounter.php

@@ -67,7 +67,7 @@ public function value()
      *
      * @param int $step
      *
-     * @return int value after increase
+     * @return int|bool value after increase or false on fail
      */
     public function inc($step = 1)
     {
@@ -79,6 +79,38 @@ public function inc($step = 1)
         );
     }
 
+    /**
+     * Update expriration time
+     *
+     * @link http://php.net/manual/en/memcached.touch.php
+     * @return bool true on success
+     */
+    public function touch()
+    {
+        return $this->client->touch(
+            $this->getKey(),
+            $this->getExpiry()
+        );
+    }
+
+    /**
+     * Increase counter and update expiry at the same time.
+     *
+     * @param int $step
+     * @see inc()
+     *
+     * @return bool|int new value or false if increase failed
+     */
+    public function incWithTouch($step = 1)
+    {
+        $new = $this->inc($step);
+        if (false !== $new) {
+            $this->touch();
+        }
+
+        return $new;
+    }
+
     /**
      * Initial counter value
      * Could be redefined in descendants