Files
oak-gpui/gpui_macros/src/lib.rs
T
2021-07-13 18:13:25 +02:00

152 lines
5.4 KiB
Rust

use proc_macro::TokenStream;
use quote::{format_ident, quote};
use std::mem;
use syn::{
parse_macro_input, parse_quote, spanned::Spanned as _, AttributeArgs, ItemFn, Lit, Meta,
NestedMeta,
};
#[proc_macro_attribute]
pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
let mut namespace = format_ident!("gpui");
let args = syn::parse_macro_input!(args as AttributeArgs);
let mut max_retries = 0;
let mut num_iterations = 1;
let mut starting_seed = 0;
for arg in args {
match arg {
NestedMeta::Meta(Meta::Path(name))
if name.get_ident().map_or(false, |n| n == "self") =>
{
namespace = format_ident!("crate");
}
NestedMeta::Meta(Meta::NameValue(meta)) => {
let key_name = meta.path.get_ident().map(|i| i.to_string());
let variable = match key_name.as_ref().map(String::as_str) {
Some("retries") => &mut max_retries,
Some("iterations") => &mut num_iterations,
Some("seed") => &mut starting_seed,
_ => {
return TokenStream::from(
syn::Error::new(meta.path.span(), "invalid argument")
.into_compile_error(),
)
}
};
*variable = match parse_int(&meta.lit) {
Ok(value) => value,
Err(error) => {
return TokenStream::from(error.into_compile_error());
}
};
}
other => {
return TokenStream::from(
syn::Error::new_spanned(other, "invalid argument").into_compile_error(),
)
}
}
}
let mut inner_fn = parse_macro_input!(function as ItemFn);
let inner_fn_attributes = mem::take(&mut inner_fn.attrs);
let inner_fn_name = format_ident!("_{}", inner_fn.sig.ident);
let outer_fn_name = mem::replace(&mut inner_fn.sig.ident, inner_fn_name.clone());
// Pass to the test function the number of app contexts that it needs,
// based on its parameter list.
let inner_fn_args = (0..inner_fn.sig.inputs.len())
.map(|i| {
let first_entity_id = i * 100_000;
quote!(#namespace::TestAppContext::new(foreground.clone(), background.clone(), #first_entity_id),)
})
.collect::<proc_macro2::TokenStream>();
let mut outer_fn: ItemFn = if inner_fn.sig.asyncness.is_some() {
parse_quote! {
#[test]
fn #outer_fn_name() {
#inner_fn
let mut retries = 0;
let mut i = 0;
loop {
let seed = #starting_seed + i;
let result = std::panic::catch_unwind(|| {
let (foreground, background) = #namespace::executor::deterministic(seed as u64);
foreground.run(#inner_fn_name(#inner_fn_args));
});
match result {
Ok(result) => {
retries = 0;
i += 1;
if i == #num_iterations {
return result
}
}
Err(error) => {
if retries < #max_retries {
retries += 1;
println!("retrying: attempt {}", retries);
} else {
if #num_iterations > 1 {
eprintln!("failing seed: {}", seed);
}
std::panic::resume_unwind(error);
}
}
}
}
}
}
} else {
parse_quote! {
#[test]
fn #outer_fn_name() {
#inner_fn
if #max_retries > 0 {
let mut retries = 0;
loop {
let result = std::panic::catch_unwind(|| {
#namespace::App::test(|cx| {
#inner_fn_name(cx);
});
});
match result {
Ok(result) => return result,
Err(error) => {
if retries < #max_retries {
retries += 1;
println!("retrying: attempt {}", retries);
} else {
std::panic::resume_unwind(error);
}
}
}
}
} else {
#namespace::App::test(|cx| {
#inner_fn_name(cx);
});
}
}
}
};
outer_fn.attrs.extend(inner_fn_attributes);
TokenStream::from(quote!(#outer_fn))
}
fn parse_int(literal: &Lit) -> syn::Result<usize> {
if let Lit::Int(int) = &literal {
int.base10_parse()
} else {
Err(syn::Error::new(literal.span(), "must be an integer"))
}
}