@@ -3,6 +3,7 @@
 import (
 	"context"
 	"io"
+	"os"
 
 	"alin.ovh/searchix/internal/config"
 	"alin.ovh/searchix/internal/file"
@@ -57,3 +58,49 @@ }
 
 	return
 }
+
+func Open(
+	source *config.Source,
+	opts *Options,
+) (*FetchedFiles, error) {
+	root := opts.Root
+
+	f := &FetchedFiles{}
+
+	rev, err := openIfExists(root, source.JoinPath("revision"))
+	if err != nil {
+		opts.Logger.Warn("failed to open revision file", "error", err)
+	}
+	if rev != nil {
+		f.Revision = rev
+	}
+
+	switch source.Importer {
+	case config.Options:
+		f.Options, err = root.Open(source.JoinPath("options.json"))
+	case config.Packages:
+		f.Packages, err = root.Open(source.JoinPath("packages.json"))
+	default:
+		err = fault.Newf("unsupported importer type %s", source.Importer.String())
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return f, nil
+}
+
+func openIfExists(root *file.Root, filename string) (*os.File, error) {
+	if exists, err := root.Exists(filename); err != nil {
+		return nil, fault.Wrap(err, fmsg.With("failed to check if file exists"))
+	} else if !exists {
+		return nil, nil
+	}
+
+	f, err := root.Open(filename)
+	if err != nil {
+		return nil, fault.Wrap(err, fmsg.Withf("failed to open file %s", filename))
+	}
+
+	return f, nil
+}