From f6639cb46d83cb9bb92a30578c10fdb372a58f04 Mon Sep 17 00:00:00 2001
From: Daniel Nephin <dnephin@docker.com>
Date: Wed, 21 Feb 2018 17:16:57 -0500
Subject: [PATCH] GetLayerFolders

Signed-off-by: Daniel Nephin <dnephin@docker.com>
---
 daemon/image_prune.go   |  2 +-
 daemon/image_windows.go | 35 +++++++++++++++++++++++++++++++++++
 daemon/oci_windows.go   | 26 +++-----------------------
 3 files changed, 39 insertions(+), 24 deletions(-)
 create mode 100644 daemon/image_windows.go

diff --git a/daemon/image_prune.go b/daemon/image_prune.go
index 8a1c2cd225..193c3aa0ac 100644
--- a/daemon/image_prune.go
+++ b/daemon/image_prune.go
@@ -1,4 +1,4 @@
-package daemon
+package daemon // import "github.com/docker/docker/daemon"
 
 import (
 	"sync/atomic"
diff --git a/daemon/image_windows.go b/daemon/image_windows.go
new file mode 100644
index 0000000000..d661400a38
--- /dev/null
+++ b/daemon/image_windows.go
@@ -0,0 +1,35 @@
+package daemon // import "github.com/docker/docker/daemon"
+
+import (
+	"github.com/docker/docker/image"
+	"github.com/docker/docker/layer"
+	"github.com/docker/docker/pkg/system"
+	"github.com/pkg/errors"
+)
+
+// GetLayerFolders returns the layer folders from an image RootFS
+func (daemon *Daemon) GetLayerFolders(img *image.Image, rwLayer layer.RWLayer) ([]string, error) {
+	folders := []string{}
+	max := len(img.RootFS.DiffIDs)
+	for index := 1; index <= max; index++ {
+		// FIXME: why does this mutate the RootFS?
+		img.RootFS.DiffIDs = img.RootFS.DiffIDs[:index]
+		if !system.IsOSSupported(img.OperatingSystem()) {
+			return nil, errors.Wrapf(system.ErrNotSupportedOperatingSystem, "cannot get layerpath for ImageID %s", img.RootFS.ChainID())
+		}
+		layerPath, err := layer.GetLayerPath(daemon.layerStores[img.OperatingSystem()], img.RootFS.ChainID())
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to get layer path from graphdriver %s for ImageID %s", daemon.layerStores[img.OperatingSystem()], img.RootFS.ChainID())
+		}
+		// Reverse order, expecting parent first
+		folders = append([]string{layerPath}, folders...)
+	}
+	if rwLayer == nil {
+		return nil, errors.New("RWLayer is unexpectedly nil")
+	}
+	m, err := rwLayer.Metadata()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to get layer metadata")
+	}
+	return append(folders, m["dir"]), nil
+}
diff --git a/daemon/oci_windows.go b/daemon/oci_windows.go
index 64c651c4af..e4b536f4e4 100644
--- a/daemon/oci_windows.go
+++ b/daemon/oci_windows.go
@@ -1,7 +1,6 @@
 package daemon // import "github.com/docker/docker/daemon"
 
 import (
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"path/filepath"
@@ -10,11 +9,11 @@ import (
 
 	containertypes "github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/container"
-	"github.com/docker/docker/layer"
 	"github.com/docker/docker/oci"
 	"github.com/docker/docker/pkg/sysinfo"
 	"github.com/docker/docker/pkg/system"
 	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/registry"
 )
@@ -139,29 +138,10 @@ func (daemon *Daemon) createSpec(c *container.Container) (*specs.Spec, error) {
 		}
 	}
 	s.Process.User.Username = c.Config.User
-
-	// Get the layer path for each layer.
-	max := len(img.RootFS.DiffIDs)
-	for i := 1; i <= max; i++ {
-		img.RootFS.DiffIDs = img.RootFS.DiffIDs[:i]
-		if !system.IsOSSupported(img.OperatingSystem()) {
-			return nil, fmt.Errorf("cannot get layerpath for ImageID %s: %s ", img.RootFS.ChainID(), system.ErrNotSupportedOperatingSystem)
-		}
-		layerPath, err := layer.GetLayerPath(daemon.layerStores[img.OperatingSystem()], img.RootFS.ChainID())
-		if err != nil {
-			return nil, fmt.Errorf("failed to get layer path from graphdriver %s for ImageID %s - %s", daemon.layerStores[img.OperatingSystem()], img.RootFS.ChainID(), err)
-		}
-		// Reverse order, expecting parent most first
-		s.Windows.LayerFolders = append([]string{layerPath}, s.Windows.LayerFolders...)
-	}
-	if c.RWLayer == nil {
-		return nil, errors.New("RWLayer of container " + c.ID + " is unexpectedly nil")
-	}
-	m, err := c.RWLayer.Metadata()
+	s.Windows.LayerFolders, err = daemon.GetLayerFolders(img, c.RWLayer)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get layer metadata - %s", err)
+		return nil, errors.Wrapf(err, "container %s", c.ID)
 	}
-	s.Windows.LayerFolders = append(s.Windows.LayerFolders, m["dir"])
 
 	dnsSearch := daemon.getDNSSearchSettings(c)