rpm: implement an RPM Resolver

The Resolver compares file paths gleaned from RPM DBs and compares them
to a Package.Filepath to try and determine if a package needs to be
removed from an index report because its RPM counterpart has already
been included.

Signed-off-by: crozzy <[email protected]>

libindex/libindex.go

@@ -110,6 +110,7 @@ func New(ctx context.Context, opts *Options, cl *http.Client) (*Libindex, error)
 	opts.Ecosystems = append(opts.Ecosystems, whiteout.NewEcosystem(ctx))
 	opts.Resolvers = []indexer.Resolver{
 		&whiteout.Resolver{},
+		&rhel.Resolver{},
 	}
 
 	if cl == nil {

rhel/resolver.go

@@ -0,0 +1,57 @@
+package rhel
+
+import (
+	"context"
+
+	"github.com/quay/zlog"
+
+	"github.com/quay/claircore"
+	"github.com/quay/claircore/indexer"
+)
+
+var (
+	_ indexer.Resolver = (*Resolver)(nil)
+)
+
+type Resolver struct{}
+
+// Resolve takes a claircore.IndexReport and uses the rpm Files
+// to determine if the package originated from an RPM. If the package
+// was deemed to have been installed via RPM, it isn't included in the
+// final report.
+func (r *Resolver) Resolve(ctx context.Context, ir *claircore.IndexReport, layers []*claircore.Layer) *claircore.IndexReport {
+	for pkgID, pkg := range ir.Packages {
+		isRPMPackage := false
+	envLoop:
+		for _, env := range ir.Environments[pkgID] {
+			if env == nil {
+				continue
+			}
+			for _, rID := range env.RepositoryIDs {
+				r := ir.Repositories[rID]
+				if r.Key == repositoryKey {
+					isRPMPackage = true
+					break envLoop
+				}
+			}
+		}
+		if !isRPMPackage {
+		filesLoop:
+			for _, fs := range ir.Files {
+				for _, f := range fs {
+					if f.Kind == claircore.FileKindRPM && f.Path == pkg.Filepath {
+						zlog.Debug(ctx).
+							Str("package name", pkg.Name).
+							Str("package file", pkg.Filepath).
+							Str("rpm file", f.Path).
+							Msg("package determined to have come from RPM, deleting")
+						delete(ir.Packages, pkgID)
+						delete(ir.Environments, pkgID)
+						break filesLoop
+					}
+				}
+			}
+		}
+	}
+	return ir
+}