Merge pull request #638 from rusterlium/resource-impl-attrs

Fix register resource_impl arg and add name override

Author: filmor

rustler/src/resource/registration.rs

@@ -17,6 +17,7 @@ use std::ptr;
 pub struct Registration {
     get_type_id: fn() -> TypeId,
     get_type_name: fn() -> &'static str,
+    type_name: Option<&'static str>,
     init: ErlNifResourceTypeInit,
 }
 
@@ -60,11 +61,19 @@ impl Registration {
             },
             get_type_name: std::any::type_name::<T>,
             get_type_id: TypeId::of::<T>,
+            type_name: None,
         }
         .maybe_add_destructor_callback::<T>()
         .maybe_add_down_callback::<T>()
     }
 
+    pub const fn with_name(self, name: &'static str) -> Self {
+        Self {
+            type_name: Some(name),
+            ..self
+        }
+    }
+
     const fn maybe_add_destructor_callback<T: Resource>(self) -> Self {
         if T::IMPLEMENTS_DESTRUCTOR || std::mem::needs_drop::<T>() {
             Self {
@@ -104,7 +113,7 @@ impl Registration {
         }
 
         let type_id = (self.get_type_id)();
-        let type_name = (self.get_type_name)();
+        let type_name = self.type_name.unwrap_or_else(self.get_type_name);
 
         let res: Option<*const ErlNifResourceType> = unsafe {
             open_resource_type(

rustler_codegen/src/lib.rs

@@ -456,8 +456,15 @@ pub fn nif_untagged_enum(input: TokenStream) -> TokenStream {
 /// }
 /// ```
 #[proc_macro_attribute]
-pub fn resource_impl(_attr: TokenStream, item: TokenStream) -> TokenStream {
+pub fn resource_impl(args: TokenStream, item: TokenStream) -> TokenStream {
+    let mut attributes = resource_impl::Attributes::default();
+
+    if !args.is_empty() {
+        let parser = syn::meta::parser(|meta| attributes.parse(meta));
+
+        syn::parse_macro_input!(args with parser);
+    }
     let input = syn::parse_macro_input!(item as syn::ItemImpl);
 
-    resource_impl::transcoder_decorator(input).into()
+    resource_impl::transcoder_decorator(attributes, input).into()
 }

rustler_codegen/src/resource_impl.rs

@@ -1,8 +1,39 @@
 use proc_macro2::{Span, TokenStream};
 use quote::quote;
 use std::collections::HashSet;
+use syn::{meta::ParseNestedMeta, LitBool, LitStr};
 
-pub fn transcoder_decorator(mut input: syn::ItemImpl) -> TokenStream {
+pub struct Attributes {
+    register: bool,
+    name: Option<String>,
+}
+
+impl Default for Attributes {
+    fn default() -> Self {
+        Self {
+            register: true,
+            name: None,
+        }
+    }
+}
+
+impl Attributes {
+    pub fn parse(&mut self, meta: ParseNestedMeta) -> syn::parse::Result<()> {
+        if meta.path.is_ident("register") {
+            let value: LitBool = meta.value()?.parse()?;
+            self.register = value.value;
+            Ok(())
+        } else if meta.path.is_ident("name") {
+            let value: LitStr = meta.value()?.parse()?;
+            self.name = Some(value.value());
+            Ok(())
+        } else {
+            Err(meta.error("Unsupported macro attribute. Expecting register or name."))
+        }
+    }
+}
+
+pub fn transcoder_decorator(attrs: Attributes, mut input: syn::ItemImpl) -> TokenStream {
     // Should be `Resource` but will fail somewhere else anyway if it isn't.
     // let (_, _trait_path, _) = input.trait_.unwrap();
     let type_path = match *input.self_ty {
@@ -32,11 +63,23 @@ pub fn transcoder_decorator(mut input: syn::ItemImpl) -> TokenStream {
         input.items.push(impl_item);
     }
 
-    quote!(
-        #input
+    let mut res = quote!(#input);
+
+    if attrs.register {
+        if let Some(name) = attrs.name {
+            res.extend(quote!(
+            rustler::codegen_runtime::inventory::submit!(
+                rustler::codegen_runtime::ResourceRegistration::new::<#type_path>().with_name(#name)
+            );
+                ));
+        } else {
+            res.extend(quote!(
+            rustler::codegen_runtime::inventory::submit!(
+                rustler::codegen_runtime::ResourceRegistration::new::<#type_path>()
+            );
+            ));
+        }
+    }
 
-        rustler::codegen_runtime::inventory::submit!(
-            rustler::codegen_runtime::ResourceRegistration::new::<#type_path>()
-        );
-    )
+    res
 }

rustler_tests/native/rustler_test/src/test_resource.rs

@@ -14,7 +14,7 @@ pub struct TestMonitorResource {
     inner: Mutex<TestMonitorResourceInner>,
 }
 
-#[rustler::resource_impl(register = true)]
+#[rustler::resource_impl(register = true, name = "monitor")]
 impl Resource for TestMonitorResource {
     fn down<'a>(&'a self, _env: Env<'a>, _pid: LocalPid, mon: Monitor) {
         let mut inner = self.inner.lock().unwrap();