feat(nix-compat): Add NixDeserialize and NixRead traits r/8585

Add a trait for deserializing a type from a daemon worker connection.
This adds the NixDeserialize trait which is kind of like the serde
Deserialize trait in that individual types are meant to implement it
and it can potentially be derived in the future.

The NixDeserialize trait takes something that implements NixRead as
input so that you can among other things mock the reader.

Change-Id: Ibb59e3562dfc822652f7d18039f00a1c0d422997
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11990
Autosubmit: Brian Olsen <me@griff.name>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

1 files changed, 9 insertions, 0 deletions

diff --git a/tvix/nix-compat/src/nix_daemon/protocol_version.rs b/tvix/nix-compat/src/nix_daemon/protocol_version.rs
index 8fd2b085c962..3c8fe663e867 100644
--- a/tvix/nix-compat/src/nix_daemon/protocol_version.rs
+++ b/tvix/nix-compat/src/nix_daemon/protocol_version.rs
@@ -1,3 +1,6 @@
+/// The latest version that is currently supported by nix-compat.
+static DEFAULT_PROTOCOL_VERSION: ProtocolVersion = ProtocolVersion::from_parts(1, 37);
+
 /// Protocol versions are represented as a u16.
 /// The upper 8 bits are the major version, the lower bits the minor.
 /// This is not aware of any endianness, use [crate::wire::read_u64] to get an
@@ -20,6 +23,12 @@ impl ProtocolVersion {
     }
 }
 
+impl Default for ProtocolVersion {
+    fn default() -> Self {
+        DEFAULT_PROTOCOL_VERSION
+    }
+}
+
 impl PartialOrd for ProtocolVersion {
     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
         Some(self.cmp(other))