Anki/rslib/build/protobuf.rs
Damien Elmes 5df684fa6b rework backend codegen to support multiple services; split out sched
Rust requires all methods of impl Trait to be in a single file, which
means we had a giant backend/mod.rs covering all exposed methods. By
using separate service definitions for the separate areas, and updating
the code generation, we can split it into more manageable chunks -
this commit starts with the scheduling code.

In the long run, we'll probably want to split up the protobuf file into
multiple files as well.

Also dropped want_release_gil() from rsbridge, and the associated method
enum. While it allows us to skip the thread save/restore and mutex unlock/
lock, it looks to only be buying about 2.5% extra performance in the
best case (tested with timeit+format_timespan), and the majority of
the backend methods deal with I/O, and thus were already releasing the
GIL.
2021-03-11 14:51:29 +10:00

94 lines
2.7 KiB
Rust

// Copyright: Ankitects Pty Ltd and contributors
// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
use std::path::PathBuf;
use std::{env, fmt::Write};
struct CustomGenerator {}
fn write_method_trait(buf: &mut String, service: &prost_build::Service) {
buf.push_str(
r#"
pub trait Service {
fn run_method(&self, method: u32, input: &[u8]) -> Result<Vec<u8>> {
match method {
"#,
);
for (idx, method) in service.methods.iter().enumerate() {
write!(
buf,
concat!(" ",
"{idx} => {{ let input = {input_type}::decode(input)?;\n",
"let output = self.{rust_method}(input)?;\n",
"let mut out_bytes = Vec::new(); output.encode(&mut out_bytes)?; Ok(out_bytes) }}, "),
idx = idx + 1,
input_type = method.input_type,
rust_method = method.name
)
.unwrap();
}
buf.push_str(
r#"
_ => Err(crate::err::AnkiError::invalid_input("invalid command")),
}
}
"#,
);
for method in &service.methods {
write!(
buf,
concat!(
" fn {method_name}(&self, input: {input_type}) -> ",
"Result<{output_type}>;\n"
),
method_name = method.name,
input_type = method.input_type,
output_type = method.output_type
)
.unwrap();
}
buf.push_str("}\n");
}
impl prost_build::ServiceGenerator for CustomGenerator {
fn generate(&mut self, service: prost_build::Service, buf: &mut String) {
write!(
buf,
"pub mod {name} {{
use super::*;
use prost::Message;
use crate::err::Result;
",
name = service.name.replace("Service", "").to_ascii_lowercase()
)
.unwrap();
write_method_trait(buf, &service);
buf.push('}');
}
}
fn service_generator() -> Box<dyn prost_build::ServiceGenerator> {
Box::new(CustomGenerator {})
}
pub fn write_backend_proto_rs() {
let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
let backend_proto;
let proto_dir;
if let Ok(proto) = env::var("BACKEND_PROTO") {
backend_proto = PathBuf::from(proto);
proto_dir = backend_proto.parent().unwrap().to_owned();
} else {
backend_proto = PathBuf::from("backend.proto");
proto_dir = PathBuf::from(".");
}
let fluent_proto = out_dir.join("fluent.proto");
let mut config = prost_build::Config::new();
config
.out_dir(&out_dir)
.service_generator(service_generator())
.compile_protos(&[&backend_proto, &fluent_proto], &[&proto_dir, &out_dir])
.unwrap();
}