onEmnapiInitialized

Author: toyobayashi

README.md

@@ -92,13 +92,25 @@ emcc -O3 \
      hello.c
 ```
 
-Use the output js in html. The default export key is `emnapiExports` on [`Module`](https://emscripten.org/docs/api_reference/module.html) object. You can change the key by predefining `NODE_GYP_MODULE_NAME`.
+Use the output js in html. The default export key is `emnapiExports` on [`Module`](https://emscripten.org/docs/api_reference/module.html) object. You can change the key by predefining `NODE_GYP_MODULE_NAME`. `onEmnapiInitialized` will be called before `onRuntimeInitialized`.
 
 ```html
 <script src="hello.js"></script>
 <script>
 // Emscripten js glue code will create a global `Module` object
+Module.onEmnapiInitialized = function (err, emnapiExports) {
+  if (err) {
+    // error handling
+    // emnapiExports === undefined
+    // Module[NODE_GYP_MODULE_NAME] === undefined
+    console.error(err);
+  } else {
+    // emnapiExports === Module[NODE_GYP_MODULE_NAME]
+  }
+};
+
 Module.onRuntimeInitialized = function () {
+  if (!('emnapiExports' in Module)) return;
   var binding = Module.emnapiExports;
   var msg = 'hello ' + binding.hello();
   window.alert(msg);
@@ -111,7 +123,12 @@ Or in Node.js.
 ```js
 const Module = require('./hello.js')
 
+Module.onEmnapiInitialized = function (err, emnapiExports) {
+  // ...
+}
+
 Module.onRuntimeInitialized = function () {
+  if (!('emnapiExports' in Module)) return
   const binding = Module.emnapiExports
   const msg = `hello ${binding.hello()}`
   console.log(msg)
@@ -214,7 +231,7 @@ Full example codes can be found [here](https://github.com/toyobayashi/emnapi/tre
 
 Output code can run in recent version modern browsers and Node.js latest LTS. IE is not supported.
 
-If a JS error is thrown on runtime initialization, Node.js process will exit. You can use `-sNODEJS_CATCH_EXIT=0` and add `ununcaughtException` handler yourself to avoid this.
+If a JS error is thrown on runtime initialization, Node.js process will exit. You can use `-sNODEJS_CATCH_EXIT=0` and add `ununcaughtException` handler yourself to avoid this. Alternatively, you can use `Module.onEmnapiInitialized` callback to catch error.
 
 ## Building
 

README_CN.md

@@ -88,13 +88,25 @@ emcc -O3 \
      hello.c
 ```
 
-把输出的 JS 引入进 HTML 使用，默认导出在 [`Module`](https://emscripten.org/docs/api_reference/module.html) 对象上的 `emnapiExports`。可通过预定义 `NODE_GYP_MODULE_NAME` 修改默认的导出键值。
+把输出的 JS 引入进 HTML 使用，默认导出在 [`Module`](https://emscripten.org/docs/api_reference/module.html) 对象上的 `emnapiExports`。可通过预定义 `NODE_GYP_MODULE_NAME` 修改默认的导出键值。`onEmnapiInitialized` 将在 `onRuntimeInitialized` 之前被调用。
 
 ```html
 <script src="hello.js"></script>
 <script>
 // Emscripten js 胶水代码会在全局创建一个 `Module` 对象
+Module.onEmnapiInitialized = function (err, emnapiExports) {
+  if (err) {
+    // 错误处理
+    // emnapiExports === undefined
+    // Module[NODE_GYP_MODULE_NAME] === undefined
+    console.error(err);
+  } else {
+    // emnapiExports === Module[NODE_GYP_MODULE_NAME]
+  }
+};
+
 Module.onRuntimeInitialized = function () {
+  if (!('emnapiExports' in Module)) return;
   var binding = Module.emnapiExports;
   var msg = 'hello ' + binding.hello();
   window.alert(msg);
@@ -107,7 +119,12 @@ Module.onRuntimeInitialized = function () {
 ```js
 const Module = require('./hello.js')
 
+Module.onEmnapiInitialized = function (err, emnapiExports) {
+  // ...
+}
+
 Module.onRuntimeInitialized = function () {
+  if (!('emnapiExports' in Module)) return
   const binding = Module.emnapiExports
   const msg = `hello ${binding.hello()}`
   console.log(msg)
@@ -211,7 +228,7 @@ cd ..
 
 输出的代码可以运行在最近版本的现代浏览器和最新的 Node.js LTS 版本。不支持 IE。
 
-如果在运行时初始化时抛出 JS 错误，Node.js 进程将会退出。可以使用`-sNODEJS_CATCH_EXIT=0` 并自己添加`uncaughtException` 事件处理器来避免这种情况。
+如果在运行时初始化时抛出 JS 错误，Node.js 进程将会退出。可以使用`-sNODEJS_CATCH_EXIT=0` 并自己添加`uncaughtException`。或者可以使用 `Module.onEmnapiInitialized` 来捕获异常。
 
 ## 构建
 

cgen.config.js

@@ -13,7 +13,7 @@ module.exports = function (_options, { isDebug, isEmscripten }) {
         // '-sERROR_ON_UNDEFINED_SYMBOLS=0', if add js function to imports.env
         "-sEXPORTED_FUNCTIONS=['_malloc','_free']",
         '-sALLOW_MEMORY_GROWTH=1',
-        '-sNODEJS_CATCH_EXIT=0',
+        // '-sNODEJS_CATCH_EXIT=0',
         ...(isDebug ? debugFlags : [])
       ]
     : []

example/index.js

@@ -6,7 +6,19 @@
     Module = require('./build/hello.js');
   }
 
+  Module.onEmnapiInitialized = function (err, emnapiExports) {
+    if (err) {
+      console.error(err);
+    } else {
+      console.log('onEmnapiInitialized', emnapiExports === Module.emnapiExports);
+    }
+  };
+
   Module.onRuntimeInitialized = function () {
+    console.log('onRuntimeInitialized');
+    if (!('emnapiExports' in Module)) {
+      return;
+    }
     var binding = Module.emnapiExports;
     var msg = 'hello ' + binding.hello();
     if (typeof window !== 'undefined') {

lib/emnapi.ts

@@ -41,7 +41,7 @@ function emnapi_create_external_uint8array (
       const u8arr = new Uint8Array(HEAPU8.buffer, external_data, byte_length)
       const handle = envObject.getCurrentScope().add(u8arr)
       if (finalize_cb !== emnapi.NULL) {
-        const status = emnapi.wrap(emnapi.WrapType.anonymous, env, handle.id, external_data, finalize_cb, finalize_hint, emnapi.NULL)
+        const status = emnapiWrap(emnapi.WrapType.anonymous, env, handle.id, external_data, finalize_cb, finalize_hint, emnapi.NULL)
         if (status === emnapi.napi_status.napi_pending_exception) {
           throw envObject.tryCatch.extractException()
         } else if (status !== emnapi.napi_status.napi_ok) {
@@ -56,4 +56,4 @@ function emnapi_create_external_uint8array (
 
 emnapiImplement('emnapi_get_module_object', emnapi_get_module_object)
 emnapiImplement('emnapi_get_module_property', emnapi_get_module_property)
-emnapiImplement('emnapi_create_external_uint8array', emnapi_create_external_uint8array)
+emnapiImplement('emnapi_create_external_uint8array', emnapi_create_external_uint8array, ['$emnapiWrap'])

lib/function.ts

@@ -1,7 +1,7 @@
 function napi_create_function (env: napi_env, utf8name: Pointer<const_char>, length: size_t, cb: napi_callback, data: void_p, result: Pointer<napi_value>): emnapi.napi_status {
   return emnapi.preamble(env, (envObject) => {
     return emnapi.checkArgs(env, [result, cb], () => {
-      const f = emnapi.createFunction(env, utf8name, length, cb, data)
+      const f = emnapiCreateFunction(env, utf8name, length, cb, data)
       const valueHandle = envObject.getCurrentScope().add(f)
       HEAP32[result >> 2] = valueHandle.id
       return emnapi.getReturnStatus(env)
@@ -132,7 +132,7 @@ function napi_get_new_target (
   })
 }
 
-emnapiImplement('napi_create_function', napi_create_function)
+emnapiImplement('napi_create_function', napi_create_function, ['$emnapiCreateFunction'])
 emnapiImplement('napi_get_cb_info', napi_get_cb_info)
 emnapiImplement('napi_call_function', napi_call_function)
 emnapiImplement('napi_new_instance', napi_new_instance)