added ability to iterate over all indexes and use index.Iterate() instead of ReadDir() to walk over the graph

Signed-off-by: Roman Strashkin <roman.strashkin@gmail.com>

daemon/daemon.go

@@ -884,10 +884,7 @@ func (daemon *Daemon) ContainerGraph() *graphdb.Database {
 
 func (daemon *Daemon) ImageGetCached(imgID string, config *runconfig.Config) (*graph.Image, error) {
 	// Retrieve all images
-	images, err := daemon.Graph().Map()
-	if err != nil {
-		return nil, err
-	}
+	images := daemon.Graph().Map()
 
 	// Store the tree in a map of map (map[parentId][childId])
 	imageMap := make(map[string]map[string]struct{})

daemon/image_delete.go

@@ -55,10 +55,7 @@ func (daemon *Daemon) imgDeleteHelper(name string, list *[]types.ImageDelete, fi
 		tag = ""
 	}
 
-	byParents, err := daemon.Graph().ByParent()
-	if err != nil {
-		return err
-	}
+	byParents := daemon.Graph().ByParent()
 
 	repos := daemon.Repositories().ByID()[img.ID]
 

daemon/info.go

@@ -17,7 +17,7 @@ import (
 )
 
 func (daemon *Daemon) SystemInfo() (*types.Info, error) {
-	images, _ := daemon.Graph().Map()
+	images := daemon.Graph().Map()
 	var imgcount int
 	if images == nil {
 		imgcount = 0