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Replace () with Singleton Salsa struct

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This commit is contained in:
Jack Rickard 2022-09-03 16:55:31 +01:00
parent a9e24d8b0d
commit 5832ad3090
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GPG key ID: 88084D7D08A72C8A
3 changed files with 65 additions and 37 deletions
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92
components/salsa-2022-macros/src/tracked_fn.rs
View file

@ -26,7 +26,7 @@ pub(crate) fn tracked_fn(
}
if let Some(s) = &args.specify {
if requires_interning(&item_fn) {
if function_type(&item_fn) == FunctionType::RequiresInterning {
return Err(syn::Error::new(
s.span(),
"tracked function takes too many arguments to have its value set with `specify`",
@ -309,11 +309,17 @@ fn configuration_struct(item_fn: &syn::ItemFn) -> syn::ItemStruct {
let visibility = &item_fn.vis;
let salsa_struct_ty = salsa_struct_ty(item_fn);
let intern_map: syn::Type = if requires_interning(item_fn) {
let key_ty = key_tuple_ty(item_fn);
parse_quote! { salsa::interned::InternedIngredient<salsa::Id, #key_ty> }
} else {
parse_quote! { salsa::interned::IdentityInterner<#salsa_struct_ty> }
let intern_map: syn::Type = match function_type(item_fn) {
FunctionType::Constant => {
parse_quote! { salsa::interned::IdentityInterner<()> }
}
FunctionType::SalsaStruct => {
parse_quote! { salsa::interned::IdentityInterner<#salsa_struct_ty> }
}
FunctionType::RequiresInterning => {
let key_ty = key_tuple_ty(item_fn);
parse_quote! { salsa::interned::InternedIngredient<salsa::Id, #key_ty> }
}
};
parse_quote! {
@ -325,16 +331,29 @@ fn configuration_struct(item_fn: &syn::ItemFn) -> syn::ItemStruct {
}
}
/// True if this fn takes more arguments.
fn requires_interning(item_fn: &syn::ItemFn) -> bool {
item_fn.sig.inputs.len() > 2
#[derive(Debug, PartialEq, Eq, Hash)]
enum FunctionType {
Constant,
SalsaStruct,
RequiresInterning,
}
fn function_type(item_fn: &syn::ItemFn) -> FunctionType {
match item_fn.sig.inputs.len() {
0 => unreachable!(
"functions have been checked to have at least a database argument by this point"
),
1 => FunctionType::Constant,
2 => FunctionType::SalsaStruct,
_ => FunctionType::RequiresInterning,
}
}
/// Every tracked fn takes a salsa struct as its second argument.
/// This fn returns the type of that second argument.
fn salsa_struct_ty(item_fn: &syn::ItemFn) -> syn::Type {
if item_fn.sig.inputs.len() == 1 {
return parse_quote! { () };
return parse_quote! { salsa::salsa_struct::Singleton };
}
match &item_fn.sig.inputs[1] {
syn::FnArg::Receiver(_) => panic!("receiver not expected"),
@ -345,10 +364,10 @@ fn salsa_struct_ty(item_fn: &syn::ItemFn) -> syn::Type {
fn fn_configuration(args: &FnArgs, item_fn: &syn::ItemFn) -> Configuration {
let jar_ty = args.jar_ty();
let salsa_struct_ty = salsa_struct_ty(item_fn);
let key_ty = if requires_interning(item_fn) {
parse_quote!(salsa::id::Id)
} else {
salsa_struct_ty.clone()
let key_ty = match function_type(item_fn) {
FunctionType::Constant => parse_quote!(()),
FunctionType::SalsaStruct => salsa_struct_ty.clone(),
FunctionType::RequiresInterning => parse_quote!(salsa::id::Id),
};
let value_ty = configuration::value_ty(&item_fn.sig);
@ -423,29 +442,32 @@ fn ingredients_for_impl(
let jar_ty = args.jar_ty();
let debug_name = crate::literal(&item_fn.sig.ident);
let intern_map: syn::Expr = if requires_interning(item_fn) {
parse_quote! {
{
let index = routes.push(
|jars| {
let jar = <DB as salsa::storage::JarFromJars<Self::Jar>>::jar_from_jars(jars);
let ingredients =
<_ as salsa::storage::HasIngredientsFor<Self::Ingredients>>::ingredient(jar);
&ingredients.intern_map
},
|jars| {
let jar = <DB as salsa::storage::JarFromJars<Self::Jar>>::jar_from_jars_mut(jars);
let ingredients =
<_ as salsa::storage::HasIngredientsFor<Self::Ingredients>>::ingredient_mut(jar);
&mut ingredients.intern_map
}
);
salsa::interned::InternedIngredient::new(index, #debug_name)
let intern_map: syn::Expr = match function_type(item_fn) {
FunctionType::Constant | FunctionType::SalsaStruct => {
parse_quote! {
salsa::interned::IdentityInterner::new()
}
}
} else {
parse_quote! {
salsa::interned::IdentityInterner::new()
FunctionType::RequiresInterning => {
parse_quote! {
{
let index = routes.push(
|jars| {
let jar = <DB as salsa::storage::JarFromJars<Self::Jar>>::jar_from_jars(jars);
let ingredients =
<_ as salsa::storage::HasIngredientsFor<Self::Ingredients>>::ingredient(jar);
&ingredients.intern_map
},
|jars| {
let jar = <DB as salsa::storage::JarFromJars<Self::Jar>>::jar_from_jars_mut(jars);
let ingredients =
<_ as salsa::storage::HasIngredientsFor<Self::Ingredients>>::ingredient_mut(jar);
&mut ingredients.intern_map
}
);
salsa::interned::InternedIngredient::new(index, #debug_name)
}
}
}
};

8
components/salsa-2022/src/salsa_struct.rs
View file

@ -4,6 +4,12 @@ pub trait SalsaStructInDb<DB: ?Sized + Database> {
fn register_dependent_fn(db: &DB, index: IngredientIndex);
}
impl<DB: ?Sized + Database> SalsaStructInDb<DB> for () {
/// A ZST that implements [`SalsaStructInDb`]
///
/// It is used for implementing "constant" tracked function
/// (ones that only take a database as an argument).
pub struct Singleton;
impl<DB: ?Sized + Database> SalsaStructInDb<DB> for Singleton {
fn register_dependent_fn(_db: &DB, _index: IngredientIndex) {}
}

2
salsa-2022-tests/tests/tracked_fn_constant.rs
View file

@ -7,7 +7,7 @@ struct Jar(tracked_fn);
trait Db: salsa::DbWithJar<Jar> {}
#[salsa::tracked(jar = Jar)]
#[salsa::tracked]
fn tracked_fn(db: &dyn Db) -> u32 {
44
}