Support named "special" operations in WebIDL

This commit adds support for two different features of the "special" operations
in WebIDL. First, it implements the desugaring [described by WebIDL][1] where
this:

    interface Dictionary {
      getter double getProperty(DOMString propertyName);
      setter void setProperty(DOMString propertyName, double propertyValue);
    };

becomes ...

    interface Dictionary {
      double getProperty(DOMString propertyName);
      void setProperty(DOMString propertyName, double propertyValue);

      getter double (DOMString propertyName);
      setter void (DOMString propertyName, double propertyValue);
    };

where specifically a named `getter` generates both a getter and a named
function.

Second it implements the distinction between two different types of getters in
WebIDL, described as:

> Getters and setters come in two varieties: ones that take a DOMString as a
> property name, known as named property getters and named property setters, and
> ones that take an unsigned long as a property index, known as indexed property
> getters and indexed property setters.

The name `get` is given to DOMString arguments, and the name `get_idx` is given
to index property getters.

[1]: https://heycam.github.io/webidl/#idl-special-operations

crates/web-sys/build.rs

@@ -65,6 +65,7 @@ fn try_main() -> Result<(), failure::Error> {
         .context("writing bindings to output file")?;
 
     // run rustfmt on the generated file - really handy for debugging
+    println!("cargo:rerun-if-env-changed=WEBIDL_RUSTFMT_BINDINGS");
     if env::var("WEBIDL_RUSTFMT_BINDINGS").is_ok() {
         let status = Command::new("rustfmt")
             .arg(&out_file_path)

crates/webidl/src/first_pass.rs

@@ -11,7 +11,7 @@ use std::collections::{BTreeMap, BTreeSet};
 
 use weedle::argument::Argument;
 use weedle::attribute::ExtendedAttribute;
-use weedle::interface::StringifierOrStatic;
+use weedle::interface::{StringifierOrStatic, Special};
 use weedle::mixin::MixinMember;
 use weedle::namespace::NamespaceMember;
 use weedle;
@@ -61,7 +61,7 @@ pub(crate) struct NamespaceData<'src> {
     pub(crate) operations: BTreeMap<OperationId<'src>, OperationData<'src>>,
 }
 
-#[derive(PartialEq, Eq, PartialOrd, Ord, Debug)]
+#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Copy)]
 pub(crate) enum OperationId<'src> {
     Constructor,
     Operation(Option<&'src str>),
@@ -171,7 +171,7 @@ fn first_pass_operation<'src>(
     record: &mut FirstPassRecord<'src>,
     first_pass_operation_type: FirstPassOperationType,
     self_name: &'src str,
-    id: OperationId<'src>,
+    ids: &[OperationId<'src>],
     arguments: &[Argument<'src>],
 ) -> Result<()> {
     let mut names = Vec::with_capacity(arguments.len());
@@ -181,7 +181,7 @@ fn first_pass_operation<'src>(
             Argument::Variadic(variadic) => names.push(variadic.identifier.0),
         }
     }
-    match first_pass_operation_type{
+    let operations = match first_pass_operation_type{
         FirstPassOperationType::Interface => {
             &mut record
                 .interfaces
@@ -203,14 +203,17 @@ fn first_pass_operation<'src>(
                 .expect(&format!("not found {} namesace", self_name))
                 .operations
         },
+    };
+    for id in ids {
+        operations
+            .entry(*id)
+            .and_modify(|operation_data| operation_data.overloaded = true)
+            .or_default()
+            .argument_names_same
+            .entry(names.clone())
+            .and_modify(|same_argument_names| *same_argument_names = true)
+            .or_insert(false);
     }
-        .entry(id)
-        .and_modify(|operation_data| operation_data.overloaded = true)
-        .or_default()
-        .argument_names_same
-        .entry(names)
-        .and_modify(|same_argument_names| *same_argument_names = true)
-        .or_insert(false);
 
     Ok(())
 }
@@ -278,7 +281,7 @@ impl<'src> FirstPass<'src, &'src str> for ExtendedAttribute<'src> {
                     record,
                     FirstPassOperationType::Interface,
                     self_name,
-                    OperationId::Constructor,
+                    &[OperationId::Constructor],
                     &list.args.body.list,
                 )
             }
@@ -287,7 +290,7 @@ impl<'src> FirstPass<'src, &'src str> for ExtendedAttribute<'src> {
                     record,
                     FirstPassOperationType::Interface,
                     self_name,
-                    OperationId::Constructor,
+                    &[OperationId::Constructor],
                     &[],
                 )
             }
@@ -298,7 +301,7 @@ impl<'src> FirstPass<'src, &'src str> for ExtendedAttribute<'src> {
                     record,
                     FirstPassOperationType::Interface,
                     self_name,
-                    OperationId::Constructor,
+                    &[OperationId::Constructor],
                     &list.args.body.list,
                 )
             }
@@ -332,7 +335,7 @@ impl<'src> FirstPass<'src, &'src str> for weedle::interface::OperationInterfaceM
             return Ok(());
         }
 
-        if !self.specials.is_empty() && self.specials.len() != 1 {
+        if self.specials.len() > 1 {
             warn!("Unsupported webidl operation {:?}", self);
             return Ok(())
         }
@@ -340,20 +343,20 @@ impl<'src> FirstPass<'src, &'src str> for weedle::interface::OperationInterfaceM
             warn!("Unsupported webidl operation {:?}", self);
             return Ok(())
         }
+        let mut ids = vec![OperationId::Operation(self.identifier.map(|s| s.0))];
+        for special in self.specials.iter() {
+            ids.push(match special {
+                Special::Getter(_) => OperationId::IndexingGetter,
+                Special::Setter(_) => OperationId::IndexingSetter,
+                Special::Deleter(_) => OperationId::IndexingDeleter,
+                Special::LegacyCaller(_) => continue,
+            });
+        }
         first_pass_operation(
             record,
             FirstPassOperationType::Interface,
             self_name,
-            match self.identifier.map(|s| s.0) {
-                None => match self.specials.get(0) {
-                    None => OperationId::Operation(None),
-                    Some(weedle::interface::Special::Getter(_)) => OperationId::IndexingGetter,
-                    Some(weedle::interface::Special::Setter(_)) => OperationId::IndexingSetter,
-                    Some(weedle::interface::Special::Deleter(_)) => OperationId::IndexingDeleter,
-                    Some(weedle::interface::Special::LegacyCaller(_)) => return Ok(()),
-                },
-                Some(ref name) => OperationId::Operation(Some(name.clone())),
-            },
+            &ids,
             &self.args.body.list,
         )
     }
@@ -434,7 +437,7 @@ impl<'src> FirstPass<'src, &'src str> for weedle::mixin::OperationMixinMember<'s
             record,
             FirstPassOperationType::Mixin,
             self_name,
-            OperationId::Operation(self.identifier.map(|s| s.0.clone())),
+            &[OperationId::Operation(self.identifier.map(|s| s.0.clone()))],
             &self.args.body.list,
         )
     }
@@ -524,7 +527,7 @@ impl<'src> FirstPass<'src, &'src str> for weedle::namespace::OperationNamespaceM
             record,
             FirstPassOperationType::Namespace,
             self_name,
-            OperationId::Operation(self.identifier.map(|s| s.0.clone())),
+            &[OperationId::Operation(self.identifier.map(|s| s.0.clone()))],
             &self.args.body.list,
         )
     }

crates/webidl/src/lib.rs

@@ -44,7 +44,7 @@ use proc_macro2::{Ident, Span};
 use weedle::argument::Argument;
 use weedle::attribute::{ExtendedAttribute, ExtendedAttributeList};
 
-use first_pass::{FirstPass, FirstPassRecord};
+use first_pass::{FirstPass, FirstPassRecord, OperationId};
 use util::{public, webidl_const_v_to_backend_const_v, TypePosition, camel_case_ident, mdn_doc};
 use idl_type::{IdlType, ToIdlType};
 
@@ -646,6 +646,7 @@ fn member_operation<'src>(
     identifier: &Option<weedle::common::Identifier<'src>>,
 ) -> Result<()> {
     use weedle::interface::StringifierOrStatic::*;
+    use weedle::interface::Special;
 
     if util::is_chrome_only(attrs) {
         return Ok(());
@@ -660,33 +661,52 @@ fn member_operation<'src>(
         None => false,
     };
 
-    for import_function in first_pass.create_basic_method(
-        args,
-        match identifier.map(|s| s.0) {
-            None if specials.is_empty() => ::first_pass::OperationId::Operation(None),
-            None if specials.len() == 1 => match specials[0] {
-                weedle::interface::Special::Getter(_) => ::first_pass::OperationId::IndexingGetter,
-                weedle::interface::Special::Setter(_) => ::first_pass::OperationId::IndexingSetter,
-                weedle::interface::Special::Deleter(_) => ::first_pass::OperationId::IndexingDeleter,
-                weedle::interface::Special::LegacyCaller(_) => return Ok(()),
-            },
-            Some(ref name) if specials.is_empty() => ::first_pass::OperationId::Operation(Some(name.clone())),
-            _ => {
-                warn!("Unsupported specials on type {:?}", (self_name, identifier));
-                return Ok(())
-            }
-        },
-        return_type,
-        self_name,
-        is_static,
-        specials.len() == 1 || first_pass
-            .interfaces
-            .get(self_name)
-            .map(|interface_data| interface_data.global)
-            .unwrap_or(false),
-        util::throws(attrs),
-    ) {
-        program.imports.push(wrap_import_function(import_function));
+    let mut operation_ids = vec![
+        OperationId::Operation(identifier.map(|s| s.0)),
+    ];
+    if specials.len() > 1 {
+        warn!(
+            "Unsupported specials ({:?}) on type {:?}",
+            specials,
+            (self_name, identifier),
+        );
+        return Ok(())
+    } else if specials.len() == 1 {
+        let id = match specials[0] {
+            Special::Getter(weedle::term::Getter) => OperationId::IndexingGetter,
+            Special::Setter(weedle::term::Setter) => OperationId::IndexingSetter,
+            Special::Deleter(weedle::term::Deleter) => OperationId::IndexingDeleter,
+            Special::LegacyCaller(weedle::term::LegacyCaller) => return Ok(()),
+        };
+        operation_ids.push(id);
+    }
+
+    for id in operation_ids {
+        let methods = first_pass
+            .create_basic_method(
+                args,
+                id,
+                return_type,
+                self_name,
+                is_static,
+                match id {
+                    OperationId::IndexingGetter |
+                    OperationId::IndexingSetter |
+                    OperationId::IndexingDeleter => true,
+                    _ => {
+                        first_pass
+                            .interfaces
+                            .get(self_name)
+                            .map(|interface_data| interface_data.global)
+                            .unwrap_or(false)
+                    }
+                },
+                util::throws(attrs),
+            );
+
+        for method in methods {
+            program.imports.push(wrap_import_function(method));
+        }
     }
     Ok(())
 }

crates/webidl/src/util.rs

@@ -370,7 +370,7 @@ impl<'src> FirstPassRecord<'src> {
     /// Create a wasm-bindgen method, if possible.
     pub fn create_basic_method(
         &self,
-        arguments: &[weedle::argument::Argument],
+        arguments: &[Argument],
         operation_id: first_pass::OperationId,
         return_type: &weedle::types::ReturnType,
         self_name: &str,
@@ -392,11 +392,11 @@ impl<'src> FirstPassRecord<'src> {
                     warn!("Operations without a name are unsupported");
                     return Vec::new();
                 }
-                Some(name) => name.to_string(),
+                Some(name) => name,
             },
-            first_pass::OperationId::IndexingGetter => "get".to_string(),
-            first_pass::OperationId::IndexingSetter => "set".to_string(),
-            first_pass::OperationId::IndexingDeleter => "delete".to_string(),
+            first_pass::OperationId::IndexingGetter => "get",
+            first_pass::OperationId::IndexingSetter => "set",
+            first_pass::OperationId::IndexingDeleter => "delete",
         };
 
         let kind = backend::ast::ImportFunctionKind::Method {
@@ -455,7 +455,7 @@ impl<'src> FirstPassRecord<'src> {
     /// whether there overloads with same argument names for given argument types
     pub fn get_operation_overloading(
         &self,
-        arguments: &[weedle::argument::Argument],
+        arguments: &[Argument],
         operation_id: &first_pass::OperationId,
         self_name: &str,
         namespace: bool,