From 1eb00e1d5b375cb79d492f1c5cd95d7317bc543c Mon Sep 17 00:00:00 2001
From: Michael Crosby <crosby.michael@gmail.com>
Date: Fri, 8 Nov 2013 15:32:50 -0800
Subject: [PATCH] Allow drivers to export their own diff

---
 container.go                | 6 +-----
 graphdriver/dummy/driver.go | 6 +++++-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/container.go b/container.go
index 6dee2335ff..32359b9cb7 100644
--- a/container.go
+++ b/container.go
@@ -1378,11 +1378,7 @@ func (container *Container) ExportRw() (archive.Archive, error) {
 	if container.runtime == nil {
 		return nil, fmt.Errorf("Can't load storage driver for unregistered container %s", container.ID)
 	}
-	imgDir, err := container.runtime.driver.Get(container.Image)
-	if err != nil {
-		return nil, err
-	}
-	return archive.ExportChanges(container.RootfsPath(), imgDir)
+	return container.runtime.driver.Diff(container.ID)
 }
 
 func (container *Container) Export() (archive.Archive, error) {
diff --git a/graphdriver/dummy/driver.go b/graphdriver/dummy/driver.go
index d62f7de27f..41a3e62a1f 100644
--- a/graphdriver/dummy/driver.go
+++ b/graphdriver/dummy/driver.go
@@ -74,7 +74,11 @@ func (d *Driver) Get(id string) (string, error) {
 }
 
 func (d *Driver) Diff(id string) (archive.Archive, error) {
-	return nil, fmt.Errorf("Not implemented")
+	p, err := d.Get(id)
+	if err != nil {
+		return nil, err
+	}
+	return archive.Tar(p, archive.Uncompressed)
 }
 
 func (d *Driver) DiffSize(id string) (int64, error) {