diff options
Diffstat (limited to 'azalea-protocol/packet-macros/src/lib.rs')
| -rwxr-xr-x | azalea-protocol/packet-macros/src/lib.rs | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/azalea-protocol/packet-macros/src/lib.rs b/azalea-protocol/packet-macros/src/lib.rs new file mode 100755 index 00000000..45df7e81 --- /dev/null +++ b/azalea-protocol/packet-macros/src/lib.rs @@ -0,0 +1,300 @@ +use proc_macro::TokenStream; +use quote::{quote, ToTokens}; +use syn::{ + self, braced, + parse::{Parse, ParseStream, Result}, + parse_macro_input, 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 write_fields = named + .iter() + .map(|f| { + let field_name = &f.ident; + let field_type = &f.ty; + // do a different buf.write_* for each field depending on the type + // if it's a string, use buf.write_string + match field_type { + syn::Type::Path(_) => { + if f.attrs.iter().any(|attr| attr.path.is_ident("varint")) { + quote! { + crate::mc_buf::McBufVarintWritable::varint_write_into(&self.#field_name, buf)?; + } + } else { + quote! { + crate::mc_buf::McBufWritable::write_into(&self.#field_name, buf)?; + } + } + } + _ => panic!( + "Error writing field {}: {}", + field_name.clone().unwrap(), + field_type.to_token_stream() + ), + } + }) + .collect::<Vec<_>>(); + + let read_fields = named + .iter() + .map(|f| { + let field_name = &f.ident; + let field_type = &f.ty; + // do a different buf.write_* for each field depending on the type + // if it's a string, use buf.write_string + match field_type { + syn::Type::Path(_) => { + if f.attrs.iter().any(|a| a.path.is_ident("varint")) { + quote! { + let #field_name = crate::mc_buf::McBufVarintReadable::varint_read_into(buf).await?; + } + } else { + quote! { + let #field_name = crate::mc_buf::McBufReadable::read_into(buf).await?; + } + } + } + _ => panic!( + "Error reading field {}: {}", + field_name.clone().unwrap(), + field_type.to_token_stream() + ), + } + }) + .collect::<Vec<_>>(); + let read_field_names = named.iter().map(|f| &f.ident).collect::<Vec<_>>(); + + quote! { + impl #ident { + pub fn get(self) -> #state { + #state::#ident(self) + } + + pub fn write(&self, buf: &mut Vec<u8>) -> Result<(), std::io::Error> { + #(#write_fields)* + Ok(()) + } + + pub async fn read<T: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send>( + buf: &mut T, + ) -> Result<#state, String> { + #(#read_fields)* + Ok(#ident { + #(#read_field_names: #read_field_names),* + }.get()) + } + } + } + .into() +} + +#[proc_macro_derive(GamePacket, attributes(varint))] +pub fn derive_game_packet(input: TokenStream) -> TokenStream { + as_packet_derive(input, quote! {crate::packets::game::GamePacket}) +} + +#[proc_macro_derive(HandshakePacket, attributes(varint))] +pub fn derive_handshake_packet(input: TokenStream) -> TokenStream { + as_packet_derive(input, quote! {crate::packets::handshake::HandshakePacket}) +} + +#[proc_macro_derive(LoginPacket, attributes(varint))] +pub fn derive_login_packet(input: TokenStream) -> TokenStream { + as_packet_derive(input, quote! {crate::packets::login::LoginPacket}) +} + +#[proc_macro_derive(StatusPacket, attributes(varint))] +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![]; + loop { + // 0x0e: clientbound_change_difficulty_packet::ClientboundChangeDifficultyPacket, + // 0x0e + let packet_id: LitInt = match input.parse() { + Ok(i) => i, + Err(_) => break, + }; + 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).await?, + }); + } + for PacketIdPair { id, module, name } in input.clientbound.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), + }); + clientbound_read_match_contents.extend(quote! { + #id => #module::#name::read(buf).await?, + }); + } + + quote! { + #[derive(Clone, Debug)] + pub enum #state_name + where + Self: Sized, + { + #enum_contents + } + + #[async_trait::async_trait] + impl crate::packets::ProtocolPacket for #state_name { + fn id(&self) -> u32 { + match self { + #id_match_contents + } + } + + fn write(&self, buf: &mut Vec<u8>) -> Result<(), std::io::Error> { + match self { + #write_match_contents + } + } + + /// Read a packet by its id, ConnectionProtocol, and flow + async fn read<T: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send>( + id: u32, + flow: &crate::connect::PacketFlow, + buf: &mut T, + ) -> Result<#state_name, String> + where + Self: Sized, + { + Ok(match flow { + crate::connect::PacketFlow::ServerToClient => match id { + #clientbound_read_match_contents + _ => panic!("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() +} |