Removing old custom RootFS behavior on Windows.

Windows base layers are no longer the special "layers+base" type, so we can remove all the special handling for that.

Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>
Upstream-commit: f342b27145d8f5af27cd5de1501551af275e899b
Component: engine

components/engine/image/rootfs.go

@@ -5,6 +5,14 @@ import "github.com/docker/docker/layer"
 // TypeLayers is used for RootFS.Type for filesystems organized into layers.
 const TypeLayers = "layers"
 
+// RootFS describes images root filesystem
+// This is currently a placeholder that only supports layers. In the future
+// this can be made into an interface that supports different implementations.
+type RootFS struct {
+	Type    string         `json:"type"`
+	DiffIDs []layer.DiffID `json:"diff_ids,omitempty"`
+}
+
 // NewRootFS returns empty RootFS struct
 func NewRootFS() *RootFS {
 	return &RootFS{Type: TypeLayers}
@@ -14,3 +22,8 @@ func NewRootFS() *RootFS {
 func (r *RootFS) Append(id layer.DiffID) {
 	r.DiffIDs = append(r.DiffIDs, id)
 }
+
+// ChainID returns the ChainID for the top layer in RootFS.
+func (r *RootFS) ChainID() layer.ChainID {
+	return layer.CreateChainID(r.DiffIDs)
+}

components/engine/image/rootfs_unix.go

@@ -1,18 +0,0 @@
-// +build !windows
-
-package image
-
-import "github.com/docker/docker/layer"
-
-// RootFS describes images root filesystem
-// This is currently a placeholder that only supports layers. In the future
-// this can be made into an interface that supports different implementations.
-type RootFS struct {
-	Type    string         `json:"type"`
-	DiffIDs []layer.DiffID `json:"diff_ids,omitempty"`
-}
-
-// ChainID returns the ChainID for the top layer in RootFS.
-func (r *RootFS) ChainID() layer.ChainID {
-	return layer.CreateChainID(r.DiffIDs)
-}

components/engine/image/rootfs_windows.go

@@ -1,48 +0,0 @@
-// +build windows
-
-package image
-
-import (
-	"crypto/sha512"
-	"fmt"
-
-	"github.com/docker/distribution/digest"
-	"github.com/docker/docker/layer"
-)
-
-// TypeLayersWithBase is used for RootFS.Type for Windows filesystems that have layers and a centrally-stored base layer.
-const TypeLayersWithBase = "layers+base"
-
-// RootFS describes images root filesystem
-// This is currently a placeholder that only supports layers. In the future
-// this can be made into an interface that supports different implementations.
-type RootFS struct {
-	Type      string         `json:"type"`
-	DiffIDs   []layer.DiffID `json:"diff_ids,omitempty"`
-	BaseLayer string         `json:"base_layer,omitempty"`
-}
-
-// BaseLayerID returns the 64 byte hex ID for the baselayer name.
-func (r *RootFS) BaseLayerID() string {
-	if r.Type != TypeLayersWithBase {
-		panic("tried to get base layer ID without a base layer")
-	}
-	baseID := sha512.Sum384([]byte(r.BaseLayer))
-	return fmt.Sprintf("%x", baseID[:32])
-}
-
-// ChainID returns the ChainID for the top layer in RootFS.
-func (r *RootFS) ChainID() layer.ChainID {
-	ids := r.DiffIDs
-	if r.Type == TypeLayersWithBase {
-		// Add an extra ID for the base.
-		baseDiffID := layer.DiffID(digest.FromBytes([]byte(r.BaseLayerID())))
-		ids = append([]layer.DiffID{baseDiffID}, ids...)
-	}
-	return layer.CreateChainID(ids)
-}
-
-// NewRootFSWithBaseLayer returns a RootFS struct with a base layer
-func NewRootFSWithBaseLayer(baseLayer string) *RootFS {
-	return &RootFS{Type: TypeLayersWithBase, BaseLayer: baseLayer}
-}

components/engine/image/spec/v1.1.md

@@ -370,10 +370,7 @@ whitespace. It has been added to this example for clarity.
 
         <ul>
           <li>
-            <code>type</code> is usually set to <code>layers</code>. There is
-            also a Windows-specific value <code>layers+base</code> that allows
-            a base layer to be specified in a field of <code>rootfs</code>
-            called <code>base_layer</code>.
+            <code>type</code> is usually set to <code>layers</code>.
           </li>
           <li>
             <code>diff_ids</code> is an array of layer content hashes (<code>DiffIDs</code>), in order from bottom-most to top-most.