JavaScript visitor API for custom transforms (parcel-bundler#363)

.github/workflows/test.yml

@@ -19,3 +19,15 @@ jobs:
       - uses: Swatinem/rust-cache@v1
       - run: cargo fmt
       - run: cargo test --all-features
+  test-js:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 18
+      - uses: bahmutov/[email protected]
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v1
+      - run: yarn build
+      - run: yarn test

.gitignore

@@ -7,4 +7,5 @@ dist/
 .parcel-cache
 node/*.flow
 artifacts
-npm
+npm
+node/ast.json

Cargo.toml

@@ -33,7 +33,8 @@ bundler = ["dashmap", "rayon"]
 cli = ["clap", "serde_json", "browserslist", "jemallocator"]
 grid = []
 nodejs = ["dep:serde"]
-serde = ["dep:serde", "smallvec/serde", "cssparser/serde"]
+serde = ["dep:serde", "smallvec/serde", "cssparser/serde", "parcel_selectors/serde"]
+jsonschema = ["schemars", "serde", "parcel_selectors/jsonschema"]
 visitor = ["lightningcss-derive"]
 
 [dependencies]
@@ -55,6 +56,7 @@ rayon = { version = "1.5.1", optional = true }
 dashmap = { version = "5.0.0", optional = true }
 serde_json = { version = "1.0.78", optional = true }
 lightningcss-derive = { version = "1.0.0-alpha.35", path = "./derive", optional = true }
+schemars = { version = "*", features = ["smallvec"], optional = true }
 
 [target.'cfg(target_os = "macos")'.dependencies]
 jemallocator = { version = "0.3.2", features = ["disable_initial_exec_tls"], optional = true }

derive/src/lib.rs

@@ -8,7 +8,7 @@ use syn::{
   GenericParam, Ident, Member, Token, Type,
 };
 
-#[proc_macro_derive(Visit, attributes(visit, skip_visit, skip_type))]
+#[proc_macro_derive(Visit, attributes(visit, skip_visit, skip_type, visit_types))]
 pub fn derive_visit_children(input: TokenStream) -> TokenStream {
   let DeriveInput {
     ident,
@@ -52,6 +52,14 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
     None
   };
 
+  let visit_types = if let Some(attr) = attrs.iter().find(|attr| attr.path.is_ident("visit_types")) {
+    let types: VisitTypes = attr.parse_args().unwrap();
+    let types = types.types;
+    Some(quote! { crate::visit_types!(#(#types)|*) })
+  } else {
+    None
+  };
+
   let mut seen_types = HashSet::new();
   let mut child_types = Vec::new();
   let mut visit = Vec::new();
@@ -66,7 +74,7 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
           continue;
         }
 
-        if !seen_types.contains(ty) && !skip_type(attrs) {
+        if visit_types.is_none() && !seen_types.contains(ty) && !skip_type(attrs) {
           seen_types.insert(ty.clone());
           child_types.push(quote! {
             <#ty as Visit<#lifetime, #t, #v>>::CHILD_TYPES.bits()
@@ -97,7 +105,8 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
               continue;
             }
 
-            if !seen_types.contains(ty) && !skip_type(attrs) && !skip_type(&variant.attrs) {
+            if visit_types.is_none() && !seen_types.contains(ty) && !skip_type(attrs) && !skip_type(&variant.attrs)
+            {
               seen_types.insert(ty.clone());
               child_types.push(quote! {
                 <#ty as Visit<#lifetime, #t, #v>>::CHILD_TYPES.bits()
@@ -137,7 +146,7 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
     _ => {}
   }
 
-  if child_types.is_empty() {
+  if visit_types.is_none() && child_types.is_empty() {
     child_types.push(quote! { crate::visitor::VisitTypes::empty().bits() });
   }
 
@@ -146,7 +155,7 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
 
     quote! {
       fn visit(&mut self, visitor: &mut #v) {
-        if #v::TYPES.contains(crate::visitor::VisitTypes::#kind) {
+        if visitor.visit_types().contains(crate::visitor::VisitTypes::#kind) {
           visitor.#visit(self)
         } else {
           self.visit_children(visitor)
@@ -160,9 +169,11 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
   let (_, ty_generics, _) = generics.split_for_impl();
   let (impl_generics, _, where_clause) = impl_generics.split_for_impl();
 
-  let child_types = quote! {
-    unsafe { crate::visitor::VisitTypes::from_bits_unchecked(#(#child_types)|*) }
-  };
+  let child_types = visit_types.unwrap_or_else(|| {
+    quote! {
+      unsafe { crate::visitor::VisitTypes::from_bits_unchecked(#(#child_types)|*) }
+    }
+  });
 
   let output = quote! {
     impl #impl_generics Visit<#lifetime, #t, #v> for #ident #ty_generics #where_clause {
@@ -171,7 +182,7 @@ pub fn derive_visit_children(input: TokenStream) -> TokenStream {
       #self_visit
 
       fn visit_children(&mut self, visitor: &mut #v) {
-        if !<Self as Visit<#lifetime, #t, #v>>::CHILD_TYPES.intersects(#v::TYPES) {
+        if !<Self as Visit<#lifetime, #t, #v>>::CHILD_TYPES.intersects(visitor.visit_types()) {
           return
         }
 
@@ -200,3 +211,19 @@ impl Parse for VisitOptions {
     Ok(Self { visit, kind })
   }
 }
+
+struct VisitTypes {
+  types: Vec<Ident>,
+}
+
+impl Parse for VisitTypes {
+  fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
+    let first: Ident = input.parse()?;
+    let mut types = vec![first];
+    while input.parse::<Token![|]>().is_ok() {
+      let id: Ident = input.parse()?;
+      types.push(id);
+    }
+    Ok(Self { types })
+  }
+}

examples/schema.rs

@@ -0,0 +1,8 @@
+fn main() {
+  #[cfg(feature = "jsonschema")]
+  {
+    let schema = schemars::schema_for!(lightningcss::stylesheet::StyleSheet);
+    let output = serde_json::to_string_pretty(&schema).unwrap();
+    let _ = std::fs::write("node/ast.json", output);
+  }
+}

node/Cargo.toml

@@ -12,8 +12,10 @@ crate-type = ["cdylib"]
 serde = { version = "1.0.123", features = ["derive"] }
 serde_bytes = "0.11.5"
 cssparser = "0.29.1"
-lightningcss = { path = "../", features = ["nodejs"] }
+lightningcss = { path = "../", features = ["nodejs", "serde", "visitor"] }
 parcel_sourcemap = { version = "2.1.1", features = ["json"] }
+serde-detach = "*"
+smallvec = { version = "1.7.0", features = ["union"] }
 
 [target.'cfg(target_os = "macos")'.dependencies]
 jemallocator = { version = "0.3.2", features = ["disable_initial_exec_tls"] }