use filetree reader instead of filetree

imgbom/analyzer/analyzer.go

@@ -9,7 +9,7 @@ import (
 type Analyzer interface {
 	Name() string
 	// TODO: add ID / Name for analyze for uniquely identifying this analyzer type
-	SelectFiles([]*tree.FileTree) []file.Reference
+	SelectFiles([]tree.FileTreeReader) []file.Reference
 	// NOTE: one of the errors which is returned is "IterationNeeded", which indicates to the driver to
 	// continue with another Select/Analyze pass
 	Analyze(map[file.Reference]string) ([]pkg.Package, error)

imgbom/analyzer/dpkg/analyzer.go

@@ -21,7 +21,7 @@ func (a *Analyzer) Name() string {
 	return "dpkg-analyzer"
 }
 
-func (a *Analyzer) SelectFiles(trees []*tree.FileTree) []file.Reference {
+func (a *Analyzer) SelectFiles(trees []tree.FileTreeReader) []file.Reference {
 	files := make([]file.Reference, 0)
 	for _, tree := range trees {
 		// TODO: extract into function/slice/etc