refactor(tvix/src/nar): drop NARCalculationService r/6270

There's only one way to calculate NAR files, by walking through them.

Things like caching such replies should be done closer to where we use
these, composing NARCalculationService doesn't actually give us much.

Instead, expose two functions, `nar::calculate_size_and_sha256` and
`nar::writer_nar`, the latter writing NAR to a writer, the former using
write_nar to only keeping the NAR size and digest.

Change-Id: Ie5d2cfea35470fdbb5cbf9da1136b0cdf0250266
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8723
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/tvix/store/src/pathinfoservice/mod.rs b/tvix/store/src/pathinfoservice/mod.rs
index 6a34e09af4..ddede58515 100644
--- a/tvix/store/src/pathinfoservice/mod.rs
+++ b/tvix/store/src/pathinfoservice/mod.rs
@@ -17,4 +17,6 @@ pub trait PathInfoService {
     /// Store a PathInfo message. Implementations MUST call validate and reject
     /// invalid messages.
     fn put(&self, path_info: proto::PathInfo) -> Result<proto::PathInfo, Error>;
+
+    // TODO: add default impl for nar calculation here, and override from GRPC client!
 }