From 706261dd4f68a19cbb31ee5357cde42f85e1d34d Mon Sep 17 00:00:00 2001
From: Patrick Henninger <donnironon@hotmail.de>
Date: Fri, 21 Dec 2018 17:11:18 +0100
Subject: [PATCH] Added InstanceIdentifier

---
 src/Cart.php                         |  7 +++++++
 src/Contracts/InstanceIdentifier.php | 20 ++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 src/Contracts/InstanceIdentifier.php

diff --git a/src/Cart.php b/src/Cart.php
index 5e8645e..10a8795 100644
--- a/src/Cart.php
+++ b/src/Cart.php
@@ -11,6 +11,7 @@ use Gloudemans\Shoppingcart\Contracts\Buyable;
 use Gloudemans\Shoppingcart\Exceptions\UnknownModelException;
 use Gloudemans\Shoppingcart\Exceptions\InvalidRowIDException;
 use Gloudemans\Shoppingcart\Exceptions\CartAlreadyStoredException;
+use Gloudemans\Shoppingcart\Contracts\InstanceIdentifier;
 
 class Cart
 {
@@ -68,6 +69,12 @@ class Cart
     {
         $instance = $instance ?: self::DEFAULT_INSTANCE;
 
+        if ($instance instanceof InstanceIdentifier)
+        {
+            $this->discount = $instance->getInstanceGlobalDiscount();
+            $this->instance = $instance->getInstanceIdentifier();
+        }
+
         $this->instance = sprintf('%s.%s', 'cart', $instance);
 
         return $this;
diff --git a/src/Contracts/InstanceIdentifier.php b/src/Contracts/InstanceIdentifier.php
new file mode 100644
index 0000000..fc49df1
--- /dev/null
+++ b/src/Contracts/InstanceIdentifier.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Gloudemans\Shoppingcart\Contracts;
+
+interface InstanceIdentifier
+{
+    /**
+     * Get the unique identifier to load the Cart from
+     *
+     * @return int|string
+     */
+    public function getInstanceIdentifier($options = null);
+
+    /**
+     * Get the unique identifier to load the Cart from
+     *
+     * @return int|string
+     */
+    public function getInstanceGlobalDiscount($options = null);
+}
\ No newline at end of file