Use a derive macro to generate message sending cast implementations

.gitignore

@@ -1 +1,2 @@
 target/*
+lu_packets_derive/target*

Cargo.lock

@@ -23,6 +23,16 @@ name = "lu_packets"
 version = "0.1.0"
 dependencies = [
  "endio 0.2.0 (git+https://github.com/lcdr/endio?rev=cb5020f6749a301ae925592f9ad1920919894ddb)",
+ "lu_packets_derive 0.1.0",
+]
+
+[[package]]
+name = "lu_packets_derive"
+version = "0.1.0"
+dependencies = [
+ "proc-macro2 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

Cargo.toml

@@ -8,3 +8,4 @@ repository = "https://github.com/lcdr/lu_packets/"
 
 [dependencies]
 endio = { git = "https://github.com/lcdr/endio", rev = "cb5020f6749a301ae925592f9ad1920919894ddb" }
+lu_packets_derive = { path = "lu_packets_derive" }

lu_packets_derive/Cargo.lock

@@ -0,0 +1,45 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "lu_packets_derive"
+version = "0.1.0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "beae6331a816b1f65d04c45b078fd8e6c93e8071771f41b8163255bbd8d7c8fa"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5304cfdf27365b7585c25d4af91b35016ed21ef88f17ced89c7093b43dba8b6"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"

lu_packets_derive/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "lu_packets_derive"
+version = "0.1.0"
+authors = ["lcdr"]
+edition = "2018"
+license = "AGPL-3.0-or-later"
+repository = "https://github.com/lcdr/lu_packets/"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0"

lu_packets_derive/src/lib.rs

@@ -0,0 +1,42 @@
+use quote::quote;
+use syn::{parse_macro_input, Data, DeriveInput, Fields};
+
+#[proc_macro_derive(FromVariants)]
+pub fn derive_deserialize(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+	let input = parse_macro_input!(input as DeriveInput);
+
+	let data = match &input.data {
+		Data::Enum(data) => data,
+		_ => panic!("only enums are supported"),
+	};
+
+	let name = &input.ident;
+
+	let mut impls = vec![];
+	for v in &data.variants {
+		let variant = &v.ident;
+		let fields = match &v.fields {
+			Fields::Named(_) => panic!("use a tuple or unit variant"),
+			Fields::Unit => { continue }
+			Fields::Unnamed(fields) => fields,
+		};
+
+		if fields.unnamed.len() != 1 {
+			panic!("use exactly one tuple argument");
+		}
+		let first = fields.unnamed.first().unwrap();
+		let variant_ty = &first.ty;
+
+		let impl_ = quote! {
+			impl ::std::convert::From<#variant_ty> for Message {
+				fn from(msg: #variant_ty) -> Self {
+					#name::#variant(msg).into()
+				}
+			}
+		};
+		impls.push(impl_);
+	}
+	(quote! {
+		#(#impls)*
+	}).into()
+}

src/auth/client.rs

@@ -2,50 +2,26 @@ use std::io::Result as Res;
 
 use endio::{LEWrite, Serialize};
 use endio::LittleEndian as LE;
+use lu_packets_derive::FromVariants;
 
-use crate::common::{LuStr33, LuWStr33, ServiceId};
-use crate::general::client::{GeneralMessage, Handshake};
+use crate::common::{LuStr33, LuWStr33};
 
+pub type LuMessage = crate::general::client::LuMessage<ClientMessage>;
 pub type Message = crate::raknet::client::Message<LuMessage>;
 
-impl From<GeneralMessage> for Message {
-	fn from(msg: GeneralMessage) -> Self {
-		LuMessage::General(msg).into()
-	}
-}
-
-impl From<Handshake> for Message {
-	fn from(msg: Handshake) -> Self {
-		GeneralMessage::Handshake(msg).into()
-	}
-}
-
-#[derive(Debug, Serialize)]
-#[repr(u16)]
-pub enum LuMessage {
-	General(GeneralMessage) = ServiceId::General as u16,
-	Client(ClientMessage) = ServiceId::Client as u16,
-}
-
-impl From<LuMessage> for Message {
-	fn from(msg: LuMessage) -> Self {
-		Message::UserMessage(msg)
-	}
-}
-
-#[derive(Debug)]
-#[non_exhaustive]
-#[repr(u32)]
-pub enum ClientMessage {
-	LoginResponse(LoginResponse),
-}
-
 impl From<ClientMessage> for Message {
 	fn from(msg: ClientMessage) -> Self {
 		LuMessage::Client(msg).into()
 	}
 }
 
+#[derive(Debug, FromVariants)]
+#[non_exhaustive]
+#[repr(u32)]
+pub enum ClientMessage {
+	LoginResponse(LoginResponse),
+}
+
 impl<'a, W: LEWrite> Serialize<LE, W> for &'a ClientMessage
 	where            u8: Serialize<LE, W>,
 	                u32: Serialize<LE, W>,
@@ -75,12 +51,6 @@ pub enum LoginResponse {
 	InvalidUsernamePassword = 6,
 }
 
-impl From<LoginResponse> for Message {
-	fn from(msg: LoginResponse) -> Self {
-		ClientMessage::LoginResponse(msg).into()
-	}
-}
-
 impl<'a, W: LEWrite> Serialize<LE, W> for &'a LoginResponse
 	where       u8: Serialize<LE, W>,
 	           u16: Serialize<LE, W>,

src/general/client.rs

@@ -5,6 +5,27 @@ use endio::LittleEndian as LE;
 
 use crate::common::ServiceId;
 
+pub type Message<C> = crate::raknet::client::Message<LuMessage<C>>;
+
+#[derive(Debug, Serialize)]
+#[repr(u16)]
+pub enum LuMessage<C> {
+	General(GeneralMessage) = ServiceId::General as u16,
+	Client(C) = ServiceId::Client as u16,
+}
+
+impl<C> From<LuMessage<C>> for Message<C> {
+	fn from(msg: LuMessage<C>) -> Self {
+		Message::UserMessage(msg)
+	}
+}
+
+impl<C> From<GeneralMessage> for Message<C> {
+	fn from(msg: GeneralMessage) -> Self {
+		LuMessage::General(msg).into()
+	}
+}
+
 #[derive(Debug)]
 #[non_exhaustive]
 #[repr(u32)]
@@ -13,6 +34,18 @@ pub enum GeneralMessage {
 	DisconnectNotify(DisconnectNotify),
 }
 
+impl<C> From<Handshake> for Message<C> {
+	fn from(msg: Handshake) -> Self {
+		GeneralMessage::Handshake(msg).into()
+	}
+}
+
+impl<C> From<DisconnectNotify> for Message<C> {
+	fn from(msg: DisconnectNotify) -> Self {
+		GeneralMessage::DisconnectNotify(msg).into()
+	}
+}
+
 impl<'a, W: LEWrite> Serialize<LE, W> for &'a GeneralMessage
 	where u8: Serialize<LE, W>,
 	     u32: Serialize<LE, W>,

src/world/client.rs

@@ -2,44 +2,20 @@ use std::io::Result as Res;
 
 use endio::{LEWrite, Serialize};
 use endio::LittleEndian as LE;
+use lu_packets_derive::FromVariants;
 
-use crate::common::{ObjId, LuWStr33, ServiceId, ZoneId};
-use crate::general::client::{DisconnectNotify, GeneralMessage, Handshake};
+use crate::common::{ObjId, LuWStr33, ZoneId};
 
+pub type LuMessage = crate::general::client::LuMessage<ClientMessage>;
 pub type Message = crate::raknet::client::Message<LuMessage>;
 
-impl From<GeneralMessage> for Message {
-	fn from(msg: GeneralMessage) -> Self {
-		LuMessage::General(msg).into()
+impl From<ClientMessage> for Message {
+	fn from(msg: ClientMessage) -> Self {
+		LuMessage::Client(msg).into()
 	}
 }
 
-impl From<Handshake> for Message {
-	fn from(msg: Handshake) -> Self {
-		GeneralMessage::Handshake(msg).into()
-	}
-}
-
-impl From<DisconnectNotify> for Message {
-	fn from(msg: DisconnectNotify) -> Self {
-		GeneralMessage::DisconnectNotify(msg).into()
-	}
-}
-
-#[derive(Debug, Serialize)]
-#[repr(u16)]
-pub enum LuMessage {
-	General(GeneralMessage) = ServiceId::General as u16,
-	Client(ClientMessage) = ServiceId::Client as u16,
-}
-
-impl From<LuMessage> for Message {
-	fn from(msg: LuMessage) -> Self {
-		Message::UserMessage(msg)
-	}
-}
-
-#[derive(Debug)]
+#[derive(Debug, FromVariants)]
 #[non_exhaustive]
 #[repr(u32)]
 pub enum ClientMessage {
@@ -48,12 +24,6 @@ pub enum ClientMessage {
 	CharacterDeleteResponse(CharacterDeleteResponse) = 11,
 }
 
-impl From<ClientMessage> for Message {
-	fn from(msg: ClientMessage) -> Self {
-		LuMessage::Client(msg).into()
-	}
-}
-
 impl<'a, W: LEWrite> Serialize<LE, W> for &'a ClientMessage
 	where                      u8: Serialize<LE, W>,
 	                          u32: Serialize<LE, W>,
@@ -85,12 +55,6 @@ pub struct CharacterListResponse {
 	pub chars: Vec<CharListChar>,
 }
 
-impl From<CharacterListResponse> for Message {
-	fn from(msg: CharacterListResponse) -> Self {
-		ClientMessage::CharacterListResponse(msg).into()
-	}
-}
-
 impl<'a, W: LEWrite> Serialize<LE, W> for &'a CharacterListResponse
 	where u8: Serialize<LE, W>,
 	     &'a CharListChar: Serialize<LE, W> {
@@ -170,19 +134,7 @@ pub enum CharacterCreateResponse {
 	CustomNameInUse,
 }
 
-impl From<CharacterCreateResponse> for Message {
-	fn from(msg: CharacterCreateResponse) -> Self {
-		ClientMessage::CharacterCreateResponse(msg).into()
-	}
-}
-
 #[derive(Debug, Serialize)]
 pub struct CharacterDeleteResponse {
 	pub success: bool,
 }
-
-impl From<CharacterDeleteResponse> for Message {
-	fn from(msg: CharacterDeleteResponse) -> Self {
-		ClientMessage::CharacterDeleteResponse(msg).into()
-	}
-}