feat(nix-compat/nar/reader): async support r/8075

This is a first cut at the async NAR reader, with some rough edges.
Poisoning is left unimplemented for now, pending future work.

Change-Id: Ifaafe0581a5e0e165a13357b909fb441f7bd8bab
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11524
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

1 files changed, 17 insertions, 0 deletions

diff --git a/tvix/nix-compat/src/nar/wire/mod.rs b/tvix/nix-compat/src/nar/wire/mod.rs
index b9e021249543..9e99b530ce15 100644
--- a/tvix/nix-compat/src/nar/wire/mod.rs
+++ b/tvix/nix-compat/src/nar/wire/mod.rs
@@ -90,6 +90,23 @@ pub const TOK_DIR: [u8; 24] = *b"\x09\0\0\0\0\0\0\0directory\0\0\0\0\0\0\0";
 pub const TOK_ENT: [u8; 48] = *b"\x05\0\0\0\0\0\0\0entry\0\0\0\x01\0\0\0\0\0\0\0(\0\0\0\0\0\0\0\x04\0\0\0\0\0\0\0name\0\0\0\0";
 pub const TOK_NOD: [u8; 48] = *b"\x04\0\0\0\0\0\0\0node\0\0\0\0\x01\0\0\0\0\0\0\0(\0\0\0\0\0\0\0\x04\0\0\0\0\0\0\0type\0\0\0\0";
 pub const TOK_PAR: [u8; 16] = *b"\x01\0\0\0\0\0\0\0)\0\0\0\0\0\0\0";
+#[cfg(feature = "async")]
+const TOK_PAD_PAR: [u8; 24] = *b"\0\0\0\0\0\0\0\0\x01\0\0\0\0\0\0\0)\0\0\0\0\0\0\0";
+
+#[cfg(feature = "async")]
+#[derive(Debug)]
+pub(crate) enum PadPar {}
+
+#[cfg(feature = "async")]
+impl crate::wire::reader::Tag for PadPar {
+    const PATTERN: &'static [u8] = &TOK_PAD_PAR;
+
+    type Buf = [u8; 24];
+
+    fn make_buf() -> Self::Buf {
+        [0; 24]
+    }
+}
 
 #[test]
 fn tokens() {