Add Postcard Codec (#20)

Add Postcard Codec gated by feature codec-postcard.

.github/workflows/rust.yml

@@ -121,6 +121,7 @@ jobs:
           - bincode
           - ciborium
           - message-pack
+          - postcard
 
     steps:
       - name: Checkout sources

.vscode/settings.json

@@ -39,5 +39,14 @@
         "structs",
         "unbuffered",
         "untrusted"
+    ],
+    "rust-analyzer.cargo.features": [
+        "full",
+        "default-codec-json",
+        "codec-bincode",
+        "codec-ciborium",
+        "codec-json",
+        "codec-message-pack",
+        "codec-postcard"
     ]
 }

remoc/Cargo.toml

@@ -31,19 +31,22 @@ codec-json = ["serde_json"]
 default-codec-json = ["codec-json", "default-codec-set"]
 codec-message-pack = ["rmp-serde"]
 default-codec-message-pack = ["codec-message-pack", "default-codec-set"]
+codec-postcard = ["postcard"]
+default-codec-postcard = ["codec-postcard", "default-codec-set"]
 full-codecs = [
     "codec-bincode",
     "codec-ciborium",
     "codec-json",
     "codec-message-pack",
+    "codec-postcard",
 ]
 
 
 [dependencies]
 remoc_macro = { version = "=0.13.0", path = "../remoc_macro", optional = true }
 
 futures = "0.3"
-tokio = { version = "1.32", features = ["macros", "rt", "sync", "time"] }
+tokio = { version = "1.34", features = ["macros", "rt", "sync", "time"] }
 tokio-util = { version = "0.7", features = ["codec"] }
 rand = "0.8"
 tracing = "0.1.29"
@@ -58,6 +61,7 @@ serde_json = { version = "1.0", optional = true }
 bincode = { version = "1.3", optional = true }
 ciborium = { version = "0.2", optional = true }
 rmp-serde = { version = "1.0", optional = true }
+postcard = { version = "1.0", features = ["use-std"] , optional = true }
 
 
 [dev-dependencies]

remoc/README.md

@@ -95,6 +95,7 @@ The following features enable data formats for transmission:
   * `codec-ciborium` provides the CBOR format.
   * `codec-json` provides the JSON format.
   * `codec-message-pack` provides the MessagePack format.
+  * `codec-postcard` provides the Postcard format.
 
 The feature `default-codec-*` selects the respective codec as default.
 At most one of this must be selected and this should only be used by

remoc/src/codec/mod.rs

@@ -194,6 +194,14 @@ pub use message_pack::MessagePack;
 #[doc(no_inline)]
 pub use message_pack::MessagePack as Default;
 
+#[cfg(feature = "codec-postcard")]
+mod postcard;
+#[cfg(feature = "codec-postcard")]
+pub use postcard::Postcard;
+#[cfg(feature = "default-codec-postcard")]
+#[doc(no_inline)]
+pub use postcard::Postcard as Default;
+
 /// Default codec is not set and cannot be used.
 ///
 /// Set one of the crate features `default-codec-*` to define the default codec.

remoc/src/codec/postcard.rs

@@ -0,0 +1,36 @@
+use serde::{Deserialize, Serialize};
+
+use super::{Codec, DeserializationError, SerializationError};
+
+/// Postcard codec.
+///
+/// See [postcard] for details.
+/// This uses the default function configuration.
+#[cfg_attr(docsrs, doc(cfg(feature = "codec-postcard")))]
+#[derive(Clone, Serialize, Deserialize)]
+pub struct Postcard;
+
+impl Codec for Postcard {
+    #[inline]
+    fn serialize<Writer, Item>(writer: Writer, item: &Item) -> Result<(), super::SerializationError>
+    where
+        Writer: std::io::Write,
+        Item: serde::Serialize,
+    {
+        postcard::to_io(item, writer).map_err(SerializationError::new)?;
+        Ok(())
+    }
+
+    #[inline]
+    fn deserialize<Reader, Item>(mut reader: Reader) -> Result<Item, super::DeserializationError>
+    where
+        Reader: std::io::Read,
+        Item: serde::de::DeserializeOwned,
+    {
+        let mut bytes = vec![];
+        reader.read_to_end(&mut bytes).map_err(DeserializationError::new)?;
+
+        let item = postcard::from_bytes(&bytes).map_err(DeserializationError::new)?;
+        Ok(item)
+    }
+}

remoc/tests/codec/mod.rs

@@ -110,3 +110,9 @@ fn json_with_attr() {
 fn message_pack() {
     roundtrip::<TestStruct, codec::MessagePack>()
 }
+
+#[cfg(feature = "codec-postcard")]
+#[test]
+fn postcard() {
+    roundtrip::<TestStruct, codec::Postcard>()
+}