1use proc_macro::TokenStream;
2use quote::{format_ident, quote};
3use std::mem;
4use syn::{
5 parse_macro_input, parse_quote, spanned::Spanned as _, AttributeArgs, FnArg, ItemFn, Lit, Meta,
6 NestedMeta, Type,
7};
8
9#[proc_macro_attribute]
10pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
11 let mut namespace = format_ident!("gpui");
12
13 let args = syn::parse_macro_input!(args as AttributeArgs);
14 let mut max_retries = 0;
15 let mut num_iterations = 1;
16 let mut starting_seed = 0;
17
18 for arg in args {
19 match arg {
20 NestedMeta::Meta(Meta::Path(name))
21 if name.get_ident().map_or(false, |n| n == "self") =>
22 {
23 namespace = format_ident!("crate");
24 }
25 NestedMeta::Meta(Meta::NameValue(meta)) => {
26 let key_name = meta.path.get_ident().map(|i| i.to_string());
27 let result = (|| {
28 match key_name.as_ref().map(String::as_str) {
29 Some("retries") => max_retries = parse_int(&meta.lit)?,
30 Some("iterations") => num_iterations = parse_int(&meta.lit)?,
31 Some("seed") => starting_seed = parse_int(&meta.lit)?,
32 _ => {
33 return Err(TokenStream::from(
34 syn::Error::new(meta.path.span(), "invalid argument")
35 .into_compile_error(),
36 ))
37 }
38 }
39 Ok(())
40 })();
41
42 if let Err(tokens) = result {
43 return tokens;
44 }
45 }
46 other => {
47 return TokenStream::from(
48 syn::Error::new_spanned(other, "invalid argument").into_compile_error(),
49 )
50 }
51 }
52 }
53
54 let mut inner_fn = parse_macro_input!(function as ItemFn);
55 if max_retries > 0 && num_iterations > 1 {
56 return TokenStream::from(
57 syn::Error::new_spanned(inner_fn, "retries and randomized iterations can't be mixed")
58 .into_compile_error(),
59 );
60 }
61 let inner_fn_attributes = mem::take(&mut inner_fn.attrs);
62 let inner_fn_name = format_ident!("_{}", inner_fn.sig.ident);
63 let outer_fn_name = mem::replace(&mut inner_fn.sig.ident, inner_fn_name.clone());
64
65 let mut outer_fn: ItemFn = if inner_fn.sig.asyncness.is_some() {
66 // Pass to the test function the number of app contexts that it needs,
67 // based on its parameter list.
68 let mut inner_fn_args = proc_macro2::TokenStream::new();
69 for (ix, arg) in inner_fn.sig.inputs.iter().enumerate() {
70 if let FnArg::Typed(arg) = arg {
71 if let Type::Path(ty) = &*arg.ty {
72 let last_segment = ty.path.segments.last();
73 match last_segment.map(|s| s.ident.to_string()).as_deref() {
74 Some("TestAppContext") => {
75 let first_entity_id = ix * 100_000;
76 inner_fn_args.extend(quote!(
77 #namespace::TestAppContext::new(
78 foreground_platform.clone(),
79 cx.platform().clone(),
80 deterministic.build_foreground(#ix),
81 deterministic.build_background(),
82 cx.font_cache().clone(),
83 #first_entity_id,
84 ),
85 ));
86 }
87 Some("StdRng") => {
88 inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(seed),));
89 }
90 Some("bool") => {
91 inner_fn_args.extend(quote!(is_last_iteration,));
92 }
93 _ => {
94 return TokenStream::from(
95 syn::Error::new_spanned(arg, "invalid argument")
96 .into_compile_error(),
97 )
98 }
99 }
100 } else {
101 return TokenStream::from(
102 syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
103 );
104 }
105 } else {
106 return TokenStream::from(
107 syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
108 );
109 }
110 }
111
112 parse_quote! {
113 #[test]
114 fn #outer_fn_name() {
115 #inner_fn
116
117 #namespace::test::run_test(
118 #num_iterations as u64,
119 #starting_seed as u64,
120 #max_retries,
121 &mut |cx, foreground_platform, deterministic, seed, is_last_iteration| {
122 cx.foreground().run(#inner_fn_name(#inner_fn_args))
123 }
124 );
125 }
126 }
127 } else {
128 let mut inner_fn_args = proc_macro2::TokenStream::new();
129 for arg in inner_fn.sig.inputs.iter() {
130 if let FnArg::Typed(arg) = arg {
131 if let Type::Path(ty) = &*arg.ty {
132 let last_segment = ty.path.segments.last();
133 match last_segment.map(|s| s.ident.to_string()).as_deref() {
134 Some("StdRng") => {
135 inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(seed),));
136 }
137 Some("bool") => {
138 inner_fn_args.extend(quote!(is_last_iteration,));
139 }
140 _ => {}
141 }
142 } else {
143 inner_fn_args.extend(quote!(cx,));
144 }
145 } else {
146 return TokenStream::from(
147 syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
148 );
149 }
150 }
151
152 parse_quote! {
153 #[test]
154 fn #outer_fn_name() {
155 #inner_fn
156
157 #namespace::test::run_test(
158 #num_iterations as u64,
159 #starting_seed as u64,
160 #max_retries,
161 &mut |cx, _, _, seed, is_last_iteration| #inner_fn_name(#inner_fn_args)
162 );
163 }
164 }
165 };
166 outer_fn.attrs.extend(inner_fn_attributes);
167
168 TokenStream::from(quote!(#outer_fn))
169}
170
171fn parse_int(literal: &Lit) -> Result<usize, TokenStream> {
172 let result = if let Lit::Int(int) = &literal {
173 int.base10_parse()
174 } else {
175 Err(syn::Error::new(literal.span(), "must be an integer"))
176 };
177
178 result.map_err(|err| TokenStream::from(err.into_compile_error()))
179}