feat(napi): support static class factory

crates/backend/src/ast.rs

@@ -34,6 +34,7 @@ pub enum NapiFnArgKind {
 pub enum FnKind {
   Normal,
   Constructor,
+  Factory,
   Getter,
   Setter,
 }

crates/backend/src/codegen/fn.rs

@@ -39,9 +39,25 @@ impl TryToTokens for NapiFn {
       }
     };
 
-    let function_call =
-      if args_len == 0 && self.fn_self.is_none() && self.kind != FnKind::Constructor {
+    let function_call = if args_len == 0
+      && self.fn_self.is_none()
+      && self.kind != FnKind::Constructor
+      && self.kind != FnKind::Factory
+    {
       quote! { #native_call }
+    } else if self.kind == FnKind::Constructor {
+      quote! {
+        let call_from_factory = ___CALL_FROM_FACTORY.load(std::sync::atomic::Ordering::Relaxed);
+        // constructor function is called from class `factory`
+        // so we should skip the original `constructor` logic
+        if call_from_factory {
+          return std::ptr::null_mut();
+        }
+        CallbackInfo::<#args_len>::new(env, cb, None).and_then(|mut cb| {
+          #(#arg_conversions)*
+          #native_call
+        })
+      }
     } else {
       quote! {
         CallbackInfo::<#args_len>::new(env, cb, None).and_then(|mut cb| {
@@ -229,6 +245,8 @@ impl NapiFn {
     if let Some(ty) = &self.ret {
       if self.kind == FnKind::Constructor {
         quote! { cb.construct(#js_name, #ret) }
+      } else if self.kind == FnKind::Factory {
+        quote! { cb.factory(#js_name, #ret) }
       } else if self.is_ret_result {
         if self.is_async {
           quote! {

crates/backend/src/typegen/fn.rs

@@ -74,6 +74,7 @@ impl NapiFn {
           Some(_) => "",
           None => "static",
         },
+        crate::FnKind::Factory => "static",
         crate::FnKind::Constructor => "",
         crate::FnKind::Getter => "get",
         crate::FnKind::Setter => "set",

crates/macro/src/parser/attrs.rs

@@ -44,6 +44,7 @@ macro_rules! attrgen {
     $mac! {
       (js_name, JsName(Span, String, Span)),
       (constructor, Constructor(Span)),
+      (factory, Factory(Span)),
       (getter, Getter(Span, Option<Ident>)),
       (setter, Setter(Span, Option<Ident>)),
       (readonly, Readonly(Span)),

crates/macro/src/parser/mod.rs

@@ -641,6 +641,10 @@ fn fn_kind(opts: &BindgenAttrs) -> FnKind {
     kind = FnKind::Constructor;
   }
 
+  if opts.factory().is_some() {
+    kind = FnKind::Factory;
+  }
+
   kind
 }
 

crates/napi/src/bindgen_runtime/callback_info.rs

@@ -1,10 +1,19 @@
+use std::ffi::c_void;
+use std::ptr;
+use std::sync::atomic::{AtomicBool, Ordering};
+
 use crate::{bindgen_prelude::*, check_status, sys, Result};
-use std::{ffi::c_void, ptr};
+
+#[doc(hidden)]
+/// Determined is `constructor` called from Class `factory`
+/// Ugly but works
+/// We can even be more ugly without `atomic`
+pub static ___CALL_FROM_FACTORY: AtomicBool = AtomicBool::new(false);
 
 pub struct CallbackInfo<const N: usize> {
   env: sys::napi_env,
   this: sys::napi_value,
-  args: [sys::napi_value; N],
+  pub args: [sys::napi_value; N],
 }
 
 impl<const N: usize> CallbackInfo<N> {
@@ -76,6 +85,39 @@ impl<const N: usize> CallbackInfo<N> {
     Ok(this)
   }
 
+  pub fn factory<T>(&self, js_name: &str, obj: T) -> Result<sys::napi_value> {
+    let obj = Box::new(obj);
+    let this = self.this();
+    let mut instance = ptr::null_mut();
+    unsafe {
+      ___CALL_FROM_FACTORY.store(true, Ordering::Relaxed);
+      let status = sys::napi_new_instance(self.env, this, 0, ptr::null_mut(), &mut instance);
+      ___CALL_FROM_FACTORY.store(false, Ordering::Relaxed);
+      // Error thrown in `constructor`
+      if status == sys::Status::napi_pending_exception {
+        let mut exception = ptr::null_mut();
+        sys::napi_get_and_clear_last_exception(self.env, &mut exception);
+        sys::napi_throw(self.env, exception);
+        return Ok(ptr::null_mut());
+      }
+
+      check_status!(
+        sys::napi_wrap(
+          self.env,
+          instance,
+          Box::into_raw(obj) as *mut std::ffi::c_void,
+          Some(raw_finalize_unchecked::<T>),
+          ptr::null_mut(),
+          &mut std::ptr::null_mut()
+        ),
+        "Failed to initialize class `{}`",
+        js_name,
+      )?;
+    };
+
+    Ok(instance)
+  }
+
   pub fn unwrap_borrow_mut<T>(&mut self) -> Result<&'static mut T>
   where
     T: FromNapiMutRef + TypeName,

crates/napi/src/bindgen_runtime/module_register.rs

@@ -79,10 +79,10 @@ unsafe extern "C" fn napi_register_module_v1(
         let (ctor, props): (Vec<_>, Vec<_>) = props.into_iter().partition(|prop| prop.is_ctor);
         // one or more or zero?
         // zero is for `#[napi(task)]`
-        if ctor.is_empty() {
+        if ctor.is_empty() && props.is_empty() {
           continue;
         }
-        let ctor = ctor[0].raw().method.unwrap();
+        let ctor = ctor.get(0).map(|c| c.raw().method.unwrap()).unwrap_or(noop);
         let raw_props: Vec<_> = props.iter().map(|prop| prop.raw()).collect();
 
         let js_class_name = CString::new(js_name).unwrap();
@@ -143,3 +143,10 @@ unsafe extern "C" fn napi_register_module_v1(
 
   exports
 }
+
+pub(crate) unsafe extern "C" fn noop(
+  _env: sys::napi_env,
+  _info: sys::napi_callback_info,
+) -> sys::napi_value {
+  ptr::null_mut()
+}

crates/napi/src/error.rs

@@ -161,9 +161,22 @@ macro_rules! impl_object_methods {
       ///
       /// This function is safety if env is not null ptr.
       pub unsafe fn throw_into(self, env: sys::napi_env) {
+        #[cfg(debug_assertions)]
+        let reason = self.0.reason.clone();
+        #[cfg(debug_assertions)]
+        let status = self.0.status;
         let js_error = self.into_value(env);
+        #[cfg(debug_assertions)]
         let throw_status = sys::napi_throw(env, js_error);
-        debug_assert!(throw_status == sys::Status::napi_ok);
+        sys::napi_throw(env, js_error);
+        #[cfg(debug_assertions)]
+        assert!(
+          throw_status == sys::Status::napi_ok,
+          "Throw error failed, status: [{}], raw message: \"{}\", raw status: [{}]",
+          Status::from(throw_status),
+          reason,
+          Status::from(status)
+        );
       }
 
       pub fn throw(&self, env: sys::napi_env) -> Result<()> {

examples/napi/__test__/typegen.spec.ts.md

@@ -48,9 +48,14 @@ Generated by [AVA](https://avajs.dev).
     export class Animal {␊
       readonly kind: Kind␊
       constructor(kind: Kind, name: string)␊
+      static withKind(kind: Kind): Animal␊
       get name(): string␊
       set name(name: string)␊
       whoami(): string␊
       static getDogKind(): Kind␊
     }␊
+    export class ClassWithFactory {␊
+      name: string␊
+      static withName(name: string): ClassWithFactory␊
+    }␊
     `

examples/napi/__test__/values.spec.ts

@@ -15,6 +15,7 @@ import {
   getCwd,
   Animal,
   Kind,
+  ClassWithFactory,
   CustomNumEnum,
   enumToI32,
   listObjKeys,
@@ -81,6 +82,20 @@ test('class', (t) => {
   t.is(dog.name, '可乐')
 })
 
+test('class factory', (t) => {
+  const duck = ClassWithFactory.withName('Default')
+  t.is(duck.name, 'Default')
+
+  duck.name = '周黑鸭'
+  t.is(duck.name, '周黑鸭')
+
+  const doge = Animal.withKind(Kind.Dog)
+  t.is(doge.name, 'Default')
+
+  doge.name = '旺财'
+  t.is(doge.name, '旺财')
+})
+
 test('callback', (t) => {
   getCwd((cwd) => {
     t.is(cwd, process.cwd())

examples/napi/index.d.ts

@@ -38,8 +38,13 @@ export function getBuffer(): Buffer
 export class Animal {
   readonly kind: Kind
   constructor(kind: Kind, name: string)
+  static withKind(kind: Kind): Animal
   get name(): string
   set name(name: string)
   whoami(): string
   static getDogKind(): Kind
 }
+export class ClassWithFactory {
+  name: string
+  static withName(name: string): ClassWithFactory
+}

examples/napi/src/class.rs

@@ -19,6 +19,14 @@ impl Animal {
     Animal { kind, name }
   }
 
+  #[napi(factory)]
+  pub fn with_kind(kind: Kind) -> Self {
+    Animal {
+      kind,
+      name: "Default".to_owned(),
+    }
+  }
+
   #[napi(getter)]
   pub fn get_name(&self) -> &str {
     self.name.as_str()

examples/napi/src/class_factory.rs

@@ -0,0 +1,14 @@
+use napi::bindgen_prelude::*;
+
+#[napi]
+pub struct ClassWithFactory {
+  pub name: String,
+}
+
+#[napi]
+impl ClassWithFactory {
+  #[napi(factory)]
+  pub fn with_name(name: String) -> Self {
+    Self { name }
+  }
+}

examples/napi/src/lib.rs

@@ -7,6 +7,7 @@ mod array;
 mod r#async;
 mod callback;
 mod class;
+mod class_factory;
 mod either;
 mod r#enum;
 mod error;