codec: replace codec! with a Codec derive [improved version]

Cargo.toml

@@ -3,6 +3,7 @@ resolver = "2"
 members = [
   "btp",
   "codec",
+  "codec/macro",
   "common",
   "keyos",
   "router",
@@ -21,7 +22,8 @@ license = "MIT OR Apache-2.0"
 bytes = "1.11.1"
 
 # workspace crates
-ql-codec = { path = "codec" }
+ql-codec = { path = "codec", features = ["derive"] }
+ql-codec-macro = { path = "codec/macro" }
 ql-common = { path = "common" }
 ql-fsm = { path = "fsm" }
 ql-keyos = { path = "keyos" }

btp/Cargo.toml

@@ -6,5 +6,4 @@ homepage.workspace = true
 license.workspace = true
 
 [dependencies]
-bytes = { workspace = true }
 ql-codec = { workspace = true }

btp/src/chunk.rs

@@ -1,7 +1,6 @@
 use std::sync::atomic::{AtomicU32, Ordering};
 
-use bytes::BufMut;
-use ql_codec::Encode;
+use ql_codec::{Encode, Writer};
 
 use crate::{Header, APP_MTU, CHUNK_DATA_SIZE, MAX_RECORD_SIZE, V2_TAG_BITS};
 
@@ -28,7 +27,7 @@ impl Iterator for Chunker<'_> {
             tagged_record_len: V2_TAG_BITS | self.data.len() as u32,
         };
         let mut chunk = [0; APP_MTU];
-        let mut output = &mut chunk[..];
+        let mut output = Writer::new(&mut chunk[..]);
         header.encode(&mut output);
         output.put_slice(data);
         self.index += 1;

btp/src/lib.rs

@@ -37,11 +37,10 @@ pub fn packet_version(data: &[u8]) -> Option<Version> {
     }
 }
 
-ql_codec::codec! {
-    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-    struct Header {
-        sequence: u16,
-        index: u16,
-        tagged_record_len: u32,
-    }
+#[derive(Debug, Clone, Copy, PartialEq, Eq, ql_codec::Codec)]
+#[codec(frozen)]
+struct Header {
+    sequence: u16,
+    index: u16,
+    tagged_record_len: u32,
 }

codec/Cargo.toml

@@ -7,3 +7,7 @@ license.workspace = true
 
 [dependencies]
 bytes = { workspace = true }
+ql-codec-macro = { workspace = true, optional = true }
+
+[features]
+derive = ["dep:ql-codec-macro"]

codec/macro/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "ql-codec-macro"
+version = "0.1.0"
+edition = "2021"
+description = "QuantumLink codec derive"
+license.workspace = true
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0.101"
+quote = "1.0.40"
+syn = { version = "2.0.106", default-features = false, features = [
+  "clone-impls",
+  "derive",
+  "parsing",
+  "printing",
+  "proc-macro",
+] }
+
+[dev-dependencies]
+ql-codec = { workspace = true, features = ["derive"] }