refactor: store external value in separated WeakMap (#134)

packages/emnapi/src/value/convert2c.ts

@@ -422,7 +422,7 @@ export function napi_get_value_external (env: napi_env, value: napi_value, resul
   from64('result')
 
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
-  const p = handle.data(envObject)
+  const p = handle.data()
   makeSetValue('result', 0, 'p', '*')
   return envObject.clearLastError()
 }

packages/emnapi/src/value/create.ts

@@ -96,7 +96,7 @@ export function napi_create_external (env: napi_env, data: void_p, finalize_cb:
     if (!emnapiCtx.feature.supportFinalizer && finalize_cb) {
       throw emnapiCtx.createNotSupportWeakRefError('napi_create_external', 'Parameter "finalize_cb" must be 0(NULL)')
     }
-    const externalHandle = emnapiCtx.getCurrentScope()!.addExternal(envObject, data)
+    const externalHandle = emnapiCtx.getCurrentScope()!.addExternal(data)
     if (finalize_cb) {
       emnapiCtx.createReferenceWithFinalizer(envObject, externalHandle.id, 0, ReferenceOwnership.kRuntime as any, finalize_cb, data, finalize_hint)
     }

packages/runtime/src/External.ts

@@ -0,0 +1,30 @@
+/** @public */
+export interface External extends Record<any, any> {}
+
+const externalValue = new WeakMap<External, number | bigint>()
+
+/** @public */
+export function isExternal (object: unknown): object is External {
+  return externalValue.has(object as any)
+}
+
+/** @public */ // eslint-disable-next-line @typescript-eslint/no-redeclare
+export const External = (() => {
+  function External (this: External, value: number | bigint): void {
+    Object.setPrototypeOf(this, null)
+    externalValue.set(this, value)
+  }
+  External.prototype = null as any
+  return External as unknown as {
+    new (value: number | bigint): External
+    prototype: null
+  }
+})()
+
+/** @public */
+export function getExternalValue (external: External): number | bigint {
+  if (!isExternal(external)) {
+    throw new TypeError('not external')
+  }
+  return externalValue.get(external)!
+}

packages/runtime/src/Handle.ts

@@ -1,14 +1,14 @@
-import type { Env } from './env'
-import { isReferenceType, _global, _Buffer } from './util'
+import { External, getExternalValue, isExternal } from './External'
+import { _global, _Buffer } from './util'
 
 export class Handle<S> {
   public constructor (
     public id: number,
     public value: S
   ) {}
 
-  public data (envObject: Env): void_p {
-    return envObject.getObjectBinding(this.value as any).data
+  public data (): void_p {
+    return getExternalValue(this.value as External) as void_p
   }
 
   public isNumber (): boolean {
@@ -28,7 +28,7 @@ export class Handle<S> {
   }
 
   public isExternal (): boolean {
-    return (isReferenceType(this.value) && Object.getPrototypeOf(this.value) === null)
+    return isExternal(this.value)
   }
 
   public isObject (): boolean {
@@ -94,11 +94,6 @@ export class ConstHandle<S extends undefined | null | boolean | typeof globalThi
   public override dispose (): void {}
 }
 
-export function External (this: any): void {
-  Object.setPrototypeOf(this, null)
-}
-External.prototype = null as any
-
 export class HandleStore {
   public static UNDEFINED = new ConstHandle(GlobalHandle.UNDEFINED, undefined)
   public static NULL = new ConstHandle(GlobalHandle.NULL, null)

packages/runtime/src/HandleScope.ts

@@ -1,6 +1,5 @@
-import type { Env } from './env'
 import type { Handle, HandleStore } from './Handle'
-import { External } from './Handle'
+import { External } from './External'
 
 export class HandleScope {
   public handleStore: HandleStore
@@ -28,13 +27,8 @@ export class HandleScope {
     return h
   }
 
-  public addExternal (envObject: Env, data: void_p): Handle<object> {
-    const value = new (External as any)()
-    const h = envObject.ctx.handleStore.push(value)
-    const binding = envObject.initObjectBinding(value)
-    binding.data = data
-    this.end++
-    return h
+  public addExternal (data: void_p): Handle<object> {
+    return this.add(new External(data))
   }
 
   public dispose (): void {

packages/runtime/src/env.ts

@@ -29,7 +29,6 @@ function handleThrow (envObject: Env, value: any): void {
 export interface IReferenceBinding {
   wrapped: number // wrapped Reference id
   tag: Uint32Array | null
-  data: void_p
 }
 
 export abstract class Env implements IStoreValue {
@@ -198,8 +197,7 @@ export abstract class Env implements IStoreValue {
   public initObjectBinding<S extends object> (value: S): IReferenceBinding {
     const binding: IReferenceBinding = {
       wrapped: 0,
-      tag: null,
-      data: 0
+      tag: null
     }
     this._bindingMap.set(value, binding)
     return binding

packages/runtime/src/index.ts

@@ -3,6 +3,7 @@ export { createContext, getDefaultContext, Context, type CleanupHookCallbackFunc
 export { Deferred, type IDeferrdValue } from './Deferred'
 export { Env, NodeEnv, type IReferenceBinding } from './env'
 export { EmnapiError, NotSupportWeakRefError, NotSupportBufferError } from './errors'
+export { External, isExternal, getExternalValue } from './External'
 export { Finalizer } from './Finalizer'
 export { TrackedFinalizer } from './TrackedFinalizer'
 export { Handle, ConstHandle, HandleStore } from './Handle'