chore(tvix/nar-bridge): move to nar-bridge-go

Make some space for the rust implementation.

Change-Id: I924dc1657be10abe5a11951c3b9de50bae06db19
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11662
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: yuka <yuka@yuka.dev>

tvix/nar-bridge-go/pkg/http/util.go

@@ -0,0 +1,24 @@
+package http
+
+import (
+	"fmt"
+	nixhash "github.com/nix-community/go-nix/pkg/hash"
+)
+
+// parseNarHashFromUrl parses a nixbase32 string representing a sha256 NarHash
+// and returns a nixhash.Hash when it was able to parse, or an error.
+func parseNarHashFromUrl(narHashFromUrl string) (*nixhash.Hash, error) {
+	// peek at the length. If it's 52 characters, assume sha256,
+	// if it's something else, this is an error.
+	l := len(narHashFromUrl)
+	if l != 52 {
+		return nil, fmt.Errorf("invalid length of narHash: %v", l)
+	}
+
+	nixHash, err := nixhash.ParseNixBase32("sha256:" + narHashFromUrl)
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse nixbase32 hash: %w", err)
+	}
+
+	return nixHash, nil
+}