refactor(nix-compat/wire): move BytesPacketPosition into writer

We don't use it in the reader anymore.

Change-Id: I98fe204a747711464e9e7ca17df06fa9854eb344
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11519
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

2 files changed, 17 insertions, 20 deletions

diff --git a/tvix/nix-compat/src/wire/bytes/mod.rs b/tvix/nix-compat/src/wire/bytes/mod.rs
index 9ec8b3fa0..0c637e6c3 100644
--- a/tvix/nix-compat/src/wire/bytes/mod.rs
+++ b/tvix/nix-compat/src/wire/bytes/mod.rs
@@ -132,25 +132,6 @@ fn padding_len(len: u64) -> u8 {
     }
 }
 
-/// Models the position inside a "bytes wire packet" that the reader or writer
-/// is in.
-/// It can be in three different stages, inside size, payload or padding fields.
-/// The number tracks the number of bytes written inside the specific field.
-/// There shall be no ambiguous states, at the end of a stage we immediately
-/// move to the beginning of the next one:
-/// - Size(LEN_SIZE) must be expressed as Payload(0)
-/// - Payload(self.payload_len) must be expressed as Padding(0)
-/// There's one exception - Size(LEN_SIZE) in the reader represents a failure
-/// state we enter in case the allowed size doesn't match the allowed range.
-///
-/// Padding(padding_len) means we're at the end of the bytes wire packet.
-#[derive(Clone, Debug, PartialEq, Eq)]
-enum BytesPacketPosition {
-    Size(usize),
-    Payload(u64),
-    Padding(usize),
-}
-
 #[cfg(test)]
 mod tests {
     use tokio_test::{assert_ok, io::Builder};
diff --git a/tvix/nix-compat/src/wire/bytes/writer.rs b/tvix/nix-compat/src/wire/bytes/writer.rs
index 347934b3d..f5632771e 100644
--- a/tvix/nix-compat/src/wire/bytes/writer.rs
+++ b/tvix/nix-compat/src/wire/bytes/writer.rs
@@ -3,7 +3,7 @@ use std::task::{ready, Poll};
 
 use tokio::io::AsyncWrite;
 
-use super::{padding_len, BytesPacketPosition, EMPTY_BYTES, LEN_SIZE};
+use super::{padding_len, EMPTY_BYTES, LEN_SIZE};
 
 pin_project! {
     /// Writes a "bytes wire packet" to the underlying writer.
@@ -41,6 +41,22 @@ pin_project! {
     }
 }
 
+/// Models the position inside a "bytes wire packet" that the writer is in.
+/// It can be in three different stages, inside size, payload or padding fields.
+/// The number tracks the number of bytes written inside the specific field.
+/// There shall be no ambiguous states, at the end of a stage we immediately
+/// move to the beginning of the next one:
+/// - Size(LEN_SIZE) must be expressed as Payload(0)
+/// - Payload(self.payload_len) must be expressed as Padding(0)
+///
+/// Padding(padding_len) means we're at the end of the bytes wire packet.
+#[derive(Clone, Debug, PartialEq, Eq)]
+enum BytesPacketPosition {
+    Size(usize),
+    Payload(u64),
+    Padding(usize),
+}
+
 impl<W> BytesWriter<W>
 where
     W: AsyncWrite,