migrate syft/cataloger to syft/pkg/cataloger

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

syft/pkg/cataloger/rpmdb/cataloger.go

@@ -0,0 +1,47 @@
+/*
+Package rpmdb provides a concrete Cataloger implementation for RPM "Package" DB files.
+*/
+package rpmdb
+
+import (
+	"fmt"
+
+	"github.com/anchore/syft/syft/pkg"
+	"github.com/anchore/syft/syft/source"
+)
+
+const catalogerName = "rpmdb-cataloger"
+
+type Cataloger struct{}
+
+// NewRpmdbCataloger returns a new RPM DB cataloger object.
+func NewRpmdbCataloger() *Cataloger {
+	return &Cataloger{}
+}
+
+// Name returns a string that uniquely describes a cataloger
+func (c *Cataloger) Name() string {
+	return catalogerName
+}
+
+// Catalog is given an object to resolve file references and content, this function returns any discovered Packages after analyzing rpm db installation.
+func (c *Cataloger) Catalog(resolver source.FileResolver) ([]pkg.Package, error) {
+	fileMatches, err := resolver.FilesByGlob(pkg.RpmDbGlob)
+	if err != nil {
+		return nil, fmt.Errorf("failed to find rpmdb's by glob: %w", err)
+	}
+
+	var pkgs []pkg.Package
+	for _, location := range fileMatches {
+		dbContentReader, err := resolver.FileContentsByLocation(location)
+		if err != nil {
+			return nil, err
+		}
+
+		pkgs, err = parseRpmDB(resolver, location, dbContentReader)
+		if err != nil {
+			return nil, fmt.Errorf("unable to catalog rpmdb package=%+v: %w", location.RealPath, err)
+		}
+	}
+	return pkgs, nil
+}