Translate ByteString in WebIDL to [u8] (#505)

In arguments take `&[u8]` and in return value return `Vec<u8>`. Should help fill
out a few more APIs on `Header` and `Response`!

crates/backend/Cargo.toml

@@ -15,8 +15,9 @@ spans = ["proc-macro2/nightly"]
 extra-traits = ["syn/extra-traits"]
 
 [dependencies]
-quote = '0.6'
+log = "0.4"
 proc-macro2 = "0.4.8"
-wasm-bindgen-shared = { path = "../shared", version = "=0.2.11" }
+quote = '0.6'
-syn = { version = '0.14', features = ['full', 'visit-mut'] }
 serde_json = "1.0"
+syn = { version = '0.14', features = ['full', 'visit-mut'] }
+wasm-bindgen-shared = { path = "../shared", version = "=0.2.11" }

crates/backend/src/defined.rs

@@ -269,7 +269,12 @@ where
         self.retain(|x| {
             let mut all_defined = true;
             x.imported_type_references(&mut |id| {
-                all_defined = all_defined && is_defined(id);
+                if all_defined {
+                    if !is_defined(id) {
+                        info!("removing due to {} not being defined", id);
+                        all_defined = false;
+                    }
+                }
             });
             all_defined
         });

crates/backend/src/lib.rs

@@ -1,6 +1,8 @@
 #![recursion_limit = "256"]
 #![cfg_attr(feature = "extra-traits", deny(missing_debug_implementations))]
 
+#[macro_use]
+extern crate log;
 extern crate proc_macro2;
 #[macro_use]
 extern crate quote;

crates/webidl/src/lib.rs

@@ -79,7 +79,7 @@ fn compile_ast(mut ast: backend::ast::Program) -> String {
     let mut defined = BTreeSet::from_iter(
         vec![
             "str", "char", "bool", "JsValue", "u8", "i8", "u16", "i16", "u32", "i32", "u64", "i64",
-            "usize", "isize", "f32", "f64", "Result",
+            "usize", "isize", "f32", "f64", "Result", "String", "Vec",
         ].into_iter()
             .map(|id| proc_macro2::Ident::new(id, proc_macro2::Span::call_site())),
     );

crates/webidl/src/util.rs

@@ -89,6 +89,30 @@ fn result_ty(t: syn::Type) -> syn::Type {
     ty.into()
 }
 
+fn slice_ty(t: syn::Type) -> syn::Type {
+    syn::TypeSlice {
+        bracket_token: Default::default(),
+        elem: Box::new(t),
+    }.into()
+}
+
+fn vec_ty(t: syn::Type) -> syn::Type {
+    let arguments = syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
+        colon2_token: None,
+        lt_token: Default::default(),
+        args: FromIterator::from_iter(vec![
+            syn::GenericArgument::Type(t),
+        ]),
+        gt_token: Default::default(),
+    });
+
+    let ident = raw_ident("Vec");
+    let seg = syn::PathSegment { ident, arguments };
+    let path: syn::Path = seg.into();
+    let ty = syn::TypePath { qself: None, path };
+    ty.into()
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum TypePosition {
     Argument,
@@ -155,10 +179,18 @@ impl<'a> FirstPassRecord<'a> {
             // `DOMString` is not supported yet in other positions.
             webidl::ast::TypeKind::DOMString => return None,
 
+            // `ByteString -> `&[u8]` for arguments
+            webidl::ast::TypeKind::ByteString if pos == TypePosition::Argument => {
+                shared_ref(slice_ty(ident_ty(raw_ident("u8"))))
+            }
+            // ... and `Vec<u8>` for arguments
+            webidl::ast::TypeKind::ByteString => {
+                vec_ty(ident_ty(raw_ident("u8")))
+            }
+
             // Support for these types is not yet implemented, so skip
             // generating any bindings for this function.
             webidl::ast::TypeKind::ArrayBuffer
-            | webidl::ast::TypeKind::ByteString
             | webidl::ast::TypeKind::DataView
             | webidl::ast::TypeKind::Error
             | webidl::ast::TypeKind::Float32Array