remove multi* content fetching from resolvers

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/source/source.go

@@ -18,7 +18,6 @@ import (
 // Source is an object that captures the data source to be cataloged, configuration, and a specific resolver used
 // in cataloging (based on the data source and configuration)
 type Source struct {
-	Resolver Resolver     // a Resolver object to use in file path/glob resolution and file contents resolution
 	Image    *image.Image // the image object to be cataloged (image only)
 	Metadata Metadata
 }
@@ -26,7 +25,7 @@ type Source struct {
 type sourceDetector func(string) (image.Source, string, error)
 
 // New produces a Source based on userInput like dir: or image:tag
-func New(userInput string, o Scope) (Source, func(), error) {
+func New(userInput string) (Source, func(), error) {
 	fs := afero.NewOsFs()
 	parsedScheme, location, err := detectScheme(fs, image.DetectSource, userInput)
 	if err != nil {
@@ -60,7 +59,7 @@ func New(userInput string, o Scope) (Source, func(), error) {
 			return Source{}, cleanup, fmt.Errorf("could not fetch image '%s': %w", location, err)
 		}
 
-		s, err := NewFromImage(img, o, location)
+		s, err := NewFromImage(img, location)
 		if err != nil {
 			return Source{}, cleanup, fmt.Errorf("could not populate source with image: %w", err)
 		}
@@ -73,9 +72,6 @@ func New(userInput string, o Scope) (Source, func(), error) {
 // NewFromDirectory creates a new source object tailored to catalog a given filesystem directory recursively.
 func NewFromDirectory(path string) (Source, error) {
 	return Source{
-		Resolver: &DirectoryResolver{
-			Path: path,
-		},
 		Metadata: Metadata{
 			Scheme: DirectoryScheme,
 			Path:   path,
@@ -85,22 +81,33 @@ func NewFromDirectory(path string) (Source, error) {
 
 // NewFromImage creates a new source object tailored to catalog a given container image, relative to the
 // option given (e.g. all-layers, squashed, etc)
-func NewFromImage(img *image.Image, scope Scope, userImageStr string) (Source, error) {
+func NewFromImage(img *image.Image, userImageStr string) (Source, error) {
 	if img == nil {
 		return Source{}, fmt.Errorf("no image given")
 	}
 
-	resolver, err := getImageResolver(img, scope)
-	if err != nil {
-		return Source{}, fmt.Errorf("could not determine file resolver: %w", err)
-	}
-
 	return Source{
-		Resolver: resolver,
-		Image:    img,
+		Image: img,
 		Metadata: Metadata{
 			Scheme:        ImageScheme,
-			ImageMetadata: NewImageMetadata(img, userImageStr, scope),
+			ImageMetadata: NewImageMetadata(img, userImageStr),
 		},
 	}, nil
 }
+
+func (s Source) FileResolver(scope Scope) (FileResolver, error) {
+	switch s.Metadata.Scheme {
+	case DirectoryScheme:
+		return newDirectoryResolver(s.Metadata.Path), nil
+	case ImageScheme:
+		switch scope {
+		case SquashedScope:
+			return newImageSquashResolver(s.Image)
+		case AllLayersScope:
+			return newAllLayersResolver(s.Image)
+		default:
+			return nil, fmt.Errorf("bad image scope provided: %+v", scope)
+		}
+	}
+	return nil, fmt.Errorf("unable to determine FilePathResolver with current scheme=%q", s.Metadata.Scheme)
+}