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|
use proc_macro::TokenStream;
use quote::{quote, ToTokens};
use syn::{
self, braced,
parse::{Parse, ParseStream, Result},
parse_macro_input, Data, DeriveInput, FieldsNamed, Ident, LitInt, Token,
};
fn as_packet_derive(input: TokenStream, state: proc_macro2::TokenStream) -> TokenStream {
let DeriveInput { ident, data, .. } = parse_macro_input!(input);
let fields = match &data {
syn::Data::Struct(syn::DataStruct { fields, .. }) => fields,
_ => panic!("#[derive(*Packet)] can only be used on structs"),
};
let FieldsNamed { named: _, .. } = match fields {
syn::Fields::Named(f) => f,
_ => panic!("#[derive(*Packet)] can only be used on structs with named fields"),
};
let contents = quote! {
impl #ident {
pub fn get(self) -> #state {
#state::#ident(self)
}
pub fn write(&self, buf: &mut impl std::io::Write) -> Result<(), std::io::Error> {
azalea_buf::McBufWritable::write_into(self, buf)
}
pub fn read(
buf: &mut impl std::io::Read,
) -> Result<#state, String> {
use azalea_buf::McBufReadable;
Ok(Self::read_into(buf)?.get())
}
}
};
contents.into()
}
#[proc_macro_derive(GamePacket, attributes(var))]
pub fn derive_game_packet(input: TokenStream) -> TokenStream {
as_packet_derive(input, quote! {crate::packets::game::GamePacket})
}
#[proc_macro_derive(HandshakePacket, attributes(var))]
pub fn derive_handshake_packet(input: TokenStream) -> TokenStream {
as_packet_derive(input, quote! {crate::packets::handshake::HandshakePacket})
}
#[proc_macro_derive(LoginPacket, attributes(var))]
pub fn derive_login_packet(input: TokenStream) -> TokenStream {
as_packet_derive(input, quote! {crate::packets::login::LoginPacket})
}
#[proc_macro_derive(StatusPacket, attributes(var))]
pub fn derive_status_packet(input: TokenStream) -> TokenStream {
as_packet_derive(input, quote! {crate::packets::status::StatusPacket})
}
#[derive(Debug)]
struct PacketIdPair {
id: u32,
module: Ident,
name: Ident,
}
#[derive(Debug)]
struct PacketIdMap {
packets: Vec<PacketIdPair>,
}
impl Parse for PacketIdMap {
fn parse(input: ParseStream) -> Result<Self> {
let mut packets = vec![];
// example:
// 0x0e: clientbound_change_difficulty_packet::ClientboundChangeDifficultyPacket,
// 0x0e
while let Ok(packet_id) = input.parse::<LitInt>() {
let packet_id = packet_id.base10_parse::<u32>()?;
// :
input.parse::<Token![:]>()?;
// clientbound_change_difficulty_packet
let module: Ident = input.parse()?;
// ::
input.parse::<Token![::]>()?;
// ClientboundChangeDifficultyPacket
let name: Ident = input.parse()?;
packets.push(PacketIdPair {
id: packet_id,
module,
name,
});
if input.parse::<Token![,]>().is_err() {
break;
}
}
Ok(PacketIdMap { packets })
}
}
#[derive(Debug)]
struct DeclareStatePackets {
name: Ident,
serverbound: PacketIdMap,
clientbound: PacketIdMap,
}
impl Parse for DeclareStatePackets {
fn parse(input: ParseStream) -> Result<Self> {
let name = input.parse()?;
input.parse::<Token![,]>()?;
let serverbound_token: Ident = input.parse()?;
if serverbound_token != "Serverbound" {
return Err(syn::Error::new(
serverbound_token.span(),
"Expected `Serverbound`",
));
}
input.parse::<Token![=>]>()?;
let content;
braced!(content in input);
let serverbound = content.parse()?;
input.parse::<Token![,]>()?;
let clientbound_token: Ident = input.parse()?;
if clientbound_token != "Clientbound" {
return Err(syn::Error::new(
clientbound_token.span(),
"Expected `Clientbound`",
));
}
input.parse::<Token![=>]>()?;
let content;
braced!(content in input);
let clientbound = content.parse()?;
Ok(DeclareStatePackets {
name,
serverbound,
clientbound,
})
}
}
#[proc_macro]
pub fn declare_state_packets(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeclareStatePackets);
let state_name = input.name;
let state_name_litstr = syn::LitStr::new(&state_name.to_string(), state_name.span());
let mut enum_contents = quote!();
let mut id_match_contents = quote!();
let mut write_match_contents = quote!();
let mut serverbound_read_match_contents = quote!();
let mut clientbound_read_match_contents = quote!();
for PacketIdPair { id, module, name } in input.serverbound.packets {
enum_contents.extend(quote! {
#name(#module::#name),
});
id_match_contents.extend(quote! {
#state_name::#name(_packet) => #id,
});
write_match_contents.extend(quote! {
#state_name::#name(packet) => packet.write(buf),
});
serverbound_read_match_contents.extend(quote! {
#id => #module::#name::read(buf)?,
});
}
for PacketIdPair { id, module, name } in input.clientbound.packets {
// let name_litstr = syn::LitStr::new(&name.to_string(), name.span());
enum_contents.extend(quote! {
#name(#module::#name),
});
id_match_contents.extend(quote! {
#state_name::#name(_packet) => #id,
});
write_match_contents.extend(quote! {
#state_name::#name(packet) => packet.write(buf),
});
clientbound_read_match_contents.extend(quote! {
#id => #module::#name::read(buf)?,
});
}
quote! {
#[derive(Clone, Debug)]
pub enum #state_name
where
Self: Sized,
{
#enum_contents
}
impl crate::packets::ProtocolPacket for #state_name {
fn id(&self) -> u32 {
match self {
#id_match_contents
}
}
fn write(&self, buf: &mut impl std::io::Write) -> Result<(), std::io::Error> {
match self {
#write_match_contents
}
}
/// Read a packet by its id, ConnectionProtocol, and flow
fn read(
id: u32,
flow: &crate::connect::PacketFlow,
buf: &mut impl std::io::Read,
) -> Result<#state_name, String>
where
Self: Sized,
{
Ok(match flow {
crate::connect::PacketFlow::ServerToClient => match id {
#clientbound_read_match_contents
_ => return Err(format!("Unknown ServerToClient {} packet id: {}", #state_name_litstr, id)),
},
crate::connect::PacketFlow::ClientToServer => match id {
#serverbound_read_match_contents
_ => return Err(format!("Unknown ClientToServer {} packet id: {}", #state_name_litstr, id)),
},
})
}
}
}
.into()
}
|
