add analyzer interface/controller and supporting package/catalog

imgbom/analyzer/analyzer.go

@@ -0,0 +1,14 @@
+package analyzer
+
+import (
+	"github.com/anchore/imgbom/imgbom/pkg"
+	"github.com/anchore/imgbom/imgbom/scope"
+	"github.com/anchore/stereoscope/pkg/file"
+)
+
+type Analyzer interface {
+	SelectFiles(scope.Scope) []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(pkg.CatalogWriter, map[file.Reference]string) error
+}

imgbom/analyzer/controller.go

@@ -0,0 +1,21 @@
+package analyzer
+
+var controllerInstance controller
+
+func init() {
+	controllerInstance = controller{
+		analyzers: make([]Analyzer, 0),
+	}
+}
+
+type controller struct {
+	analyzers []Analyzer
+}
+
+func (c *controller) add(a Analyzer) {
+	c.analyzers = append(c.analyzers, a)
+}
+
+func Add(a Analyzer) {
+	controllerInstance.add(a)
+}