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N-API C++ addon causing Electron GUI to block


Is there a C++ gdb GUI for Linux?Incorrect result after serializing and deserializing time_t variableWhat is Linux’s native GUI API?Calling Node Native Addons (C++) in ElectronElectron crashes with C++ addon using openssl libraryNode Addons (C++) in ElectronAngular / Electron using the renderer.js with angular componentsProblem requiring native c++ addon from electronError while building c++ addon, whats the solution for it?






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0















I have an N-API C++ addon that I would like to use with an Electron GUI. Currently the C++ addon has a simple function that sleeps for 10 seconds and then performs a computation of 8*2, and returns the value to the Javascript code. The Javascript code runs the C++ addon every 10 seconds.



// index.js
const addon = require('./build/Release/module');
const electron = require('electron');
const app, BrowserWindow = require('electron');
let win;

function createWindow()
win = new BrowserWindow(width: 800, height: 600);
win.loadFile('./index.html');
win.on('closed', () => win = null);


app.on('ready', createWindow);

app.on('activate', () =>
if (win === null)
createWindow();

)


function getInfoFromNativeModule()
const value = 8;
console.log(`$value times 2 equals`, addon.my_function(value));
setTimeout(getInfoFromNativeModule, 1000);


getInfoFromNativeModule();


However, when I run the above code I find that the native C++ addon causes the Electron GUI to block for 10 seconds, each time it runs. Is there any way that I can perform my heavy computation in the background and have the Electron GUI not block or freeze? I assume I would have to use some sort of threads but I'm not sure how to do it with N-API. Below are the rest of my files including the module.cpp and the package.json file.



// module.cpp
napi_value MyFunction(napi_env env, napi_callback_info info)
napi_status status;
size_t argc = 1;
int number = 0;
napi_value argv[1];
status = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);

if (status != napi_ok)
napi_throw_error(env, NULL, "Failed to parse arguments");


status = napi_get_value_int32(env, argv[0], &number);

if (status != napi_ok)
napi_throw_error(env, NULL, "Invalid number was passed as argument");

napi_value myNumber;
number = number * 2;
std::cout << "sleeping for 10 seconds" << std::endl;
sleep(10);
std::cout << "waking up" << std::endl;
status = napi_create_int32(env, number, &myNumber);

if (status != napi_ok)
napi_throw_error(env, NULL, "Unable to create return value");


return myNumber;


napi_value Init(napi_env env, napi_value exports)
napi_status status;
napi_value fn;

status = napi_create_function(env, NULL, 0, MyFunction, NULL, &fn);
if (status != napi_ok)
napi_throw_error(env, NULL, "Unable to wrap native function");


status = napi_set_named_property(env, exports, "my_function", fn);
if (status != napi_ok)
napi_throw_error(env, NULL, "Unable to populate exports");


return exports;


NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)



// package.json

"name": "n-api-article",
"version": "0.1.0",
"main": "index.js",
"scripts":
"start": "node-gyp rebuild && electron .",
"test": "echo "Error: no test specified" && exit 1"
,
"repository":
"type": "git",
"url": "git+https://github.com/schahriar/n-api-article.git"
,
"engines":
"node": ">=8.4.0"
,
"dependencies":
"electron": "^4.0.8",
"electron-rebuild": "^1.8.4"











share|improve this question




























    0















    I have an N-API C++ addon that I would like to use with an Electron GUI. Currently the C++ addon has a simple function that sleeps for 10 seconds and then performs a computation of 8*2, and returns the value to the Javascript code. The Javascript code runs the C++ addon every 10 seconds.



    // index.js
    const addon = require('./build/Release/module');
    const electron = require('electron');
    const app, BrowserWindow = require('electron');
    let win;

    function createWindow()
    win = new BrowserWindow(width: 800, height: 600);
    win.loadFile('./index.html');
    win.on('closed', () => win = null);


    app.on('ready', createWindow);

    app.on('activate', () =>
    if (win === null)
    createWindow();

    )


    function getInfoFromNativeModule()
    const value = 8;
    console.log(`$value times 2 equals`, addon.my_function(value));
    setTimeout(getInfoFromNativeModule, 1000);


    getInfoFromNativeModule();


    However, when I run the above code I find that the native C++ addon causes the Electron GUI to block for 10 seconds, each time it runs. Is there any way that I can perform my heavy computation in the background and have the Electron GUI not block or freeze? I assume I would have to use some sort of threads but I'm not sure how to do it with N-API. Below are the rest of my files including the module.cpp and the package.json file.



    // module.cpp
    napi_value MyFunction(napi_env env, napi_callback_info info)
    napi_status status;
    size_t argc = 1;
    int number = 0;
    napi_value argv[1];
    status = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);

    if (status != napi_ok)
    napi_throw_error(env, NULL, "Failed to parse arguments");


    status = napi_get_value_int32(env, argv[0], &number);

    if (status != napi_ok)
    napi_throw_error(env, NULL, "Invalid number was passed as argument");

    napi_value myNumber;
    number = number * 2;
    std::cout << "sleeping for 10 seconds" << std::endl;
    sleep(10);
    std::cout << "waking up" << std::endl;
    status = napi_create_int32(env, number, &myNumber);

    if (status != napi_ok)
    napi_throw_error(env, NULL, "Unable to create return value");


    return myNumber;


    napi_value Init(napi_env env, napi_value exports)
    napi_status status;
    napi_value fn;

    status = napi_create_function(env, NULL, 0, MyFunction, NULL, &fn);
    if (status != napi_ok)
    napi_throw_error(env, NULL, "Unable to wrap native function");


    status = napi_set_named_property(env, exports, "my_function", fn);
    if (status != napi_ok)
    napi_throw_error(env, NULL, "Unable to populate exports");


    return exports;


    NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)



    // package.json

    "name": "n-api-article",
    "version": "0.1.0",
    "main": "index.js",
    "scripts":
    "start": "node-gyp rebuild && electron .",
    "test": "echo "Error: no test specified" && exit 1"
    ,
    "repository":
    "type": "git",
    "url": "git+https://github.com/schahriar/n-api-article.git"
    ,
    "engines":
    "node": ">=8.4.0"
    ,
    "dependencies":
    "electron": "^4.0.8",
    "electron-rebuild": "^1.8.4"











    share|improve this question
























      0












      0








      0








      I have an N-API C++ addon that I would like to use with an Electron GUI. Currently the C++ addon has a simple function that sleeps for 10 seconds and then performs a computation of 8*2, and returns the value to the Javascript code. The Javascript code runs the C++ addon every 10 seconds.



      // index.js
      const addon = require('./build/Release/module');
      const electron = require('electron');
      const app, BrowserWindow = require('electron');
      let win;

      function createWindow()
      win = new BrowserWindow(width: 800, height: 600);
      win.loadFile('./index.html');
      win.on('closed', () => win = null);


      app.on('ready', createWindow);

      app.on('activate', () =>
      if (win === null)
      createWindow();

      )


      function getInfoFromNativeModule()
      const value = 8;
      console.log(`$value times 2 equals`, addon.my_function(value));
      setTimeout(getInfoFromNativeModule, 1000);


      getInfoFromNativeModule();


      However, when I run the above code I find that the native C++ addon causes the Electron GUI to block for 10 seconds, each time it runs. Is there any way that I can perform my heavy computation in the background and have the Electron GUI not block or freeze? I assume I would have to use some sort of threads but I'm not sure how to do it with N-API. Below are the rest of my files including the module.cpp and the package.json file.



      // module.cpp
      napi_value MyFunction(napi_env env, napi_callback_info info)
      napi_status status;
      size_t argc = 1;
      int number = 0;
      napi_value argv[1];
      status = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);

      if (status != napi_ok)
      napi_throw_error(env, NULL, "Failed to parse arguments");


      status = napi_get_value_int32(env, argv[0], &number);

      if (status != napi_ok)
      napi_throw_error(env, NULL, "Invalid number was passed as argument");

      napi_value myNumber;
      number = number * 2;
      std::cout << "sleeping for 10 seconds" << std::endl;
      sleep(10);
      std::cout << "waking up" << std::endl;
      status = napi_create_int32(env, number, &myNumber);

      if (status != napi_ok)
      napi_throw_error(env, NULL, "Unable to create return value");


      return myNumber;


      napi_value Init(napi_env env, napi_value exports)
      napi_status status;
      napi_value fn;

      status = napi_create_function(env, NULL, 0, MyFunction, NULL, &fn);
      if (status != napi_ok)
      napi_throw_error(env, NULL, "Unable to wrap native function");


      status = napi_set_named_property(env, exports, "my_function", fn);
      if (status != napi_ok)
      napi_throw_error(env, NULL, "Unable to populate exports");


      return exports;


      NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)



      // package.json

      "name": "n-api-article",
      "version": "0.1.0",
      "main": "index.js",
      "scripts":
      "start": "node-gyp rebuild && electron .",
      "test": "echo "Error: no test specified" && exit 1"
      ,
      "repository":
      "type": "git",
      "url": "git+https://github.com/schahriar/n-api-article.git"
      ,
      "engines":
      "node": ">=8.4.0"
      ,
      "dependencies":
      "electron": "^4.0.8",
      "electron-rebuild": "^1.8.4"











      share|improve this question














      I have an N-API C++ addon that I would like to use with an Electron GUI. Currently the C++ addon has a simple function that sleeps for 10 seconds and then performs a computation of 8*2, and returns the value to the Javascript code. The Javascript code runs the C++ addon every 10 seconds.



      // index.js
      const addon = require('./build/Release/module');
      const electron = require('electron');
      const app, BrowserWindow = require('electron');
      let win;

      function createWindow()
      win = new BrowserWindow(width: 800, height: 600);
      win.loadFile('./index.html');
      win.on('closed', () => win = null);


      app.on('ready', createWindow);

      app.on('activate', () =>
      if (win === null)
      createWindow();

      )


      function getInfoFromNativeModule()
      const value = 8;
      console.log(`$value times 2 equals`, addon.my_function(value));
      setTimeout(getInfoFromNativeModule, 1000);


      getInfoFromNativeModule();


      However, when I run the above code I find that the native C++ addon causes the Electron GUI to block for 10 seconds, each time it runs. Is there any way that I can perform my heavy computation in the background and have the Electron GUI not block or freeze? I assume I would have to use some sort of threads but I'm not sure how to do it with N-API. Below are the rest of my files including the module.cpp and the package.json file.



      // module.cpp
      napi_value MyFunction(napi_env env, napi_callback_info info)
      napi_status status;
      size_t argc = 1;
      int number = 0;
      napi_value argv[1];
      status = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);

      if (status != napi_ok)
      napi_throw_error(env, NULL, "Failed to parse arguments");


      status = napi_get_value_int32(env, argv[0], &number);

      if (status != napi_ok)
      napi_throw_error(env, NULL, "Invalid number was passed as argument");

      napi_value myNumber;
      number = number * 2;
      std::cout << "sleeping for 10 seconds" << std::endl;
      sleep(10);
      std::cout << "waking up" << std::endl;
      status = napi_create_int32(env, number, &myNumber);

      if (status != napi_ok)
      napi_throw_error(env, NULL, "Unable to create return value");


      return myNumber;


      napi_value Init(napi_env env, napi_value exports)
      napi_status status;
      napi_value fn;

      status = napi_create_function(env, NULL, 0, MyFunction, NULL, &fn);
      if (status != napi_ok)
      napi_throw_error(env, NULL, "Unable to wrap native function");


      status = napi_set_named_property(env, exports, "my_function", fn);
      if (status != napi_ok)
      napi_throw_error(env, NULL, "Unable to populate exports");


      return exports;


      NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)



      // package.json

      "name": "n-api-article",
      "version": "0.1.0",
      "main": "index.js",
      "scripts":
      "start": "node-gyp rebuild && electron .",
      "test": "echo "Error: no test specified" && exit 1"
      ,
      "repository":
      "type": "git",
      "url": "git+https://github.com/schahriar/n-api-article.git"
      ,
      "engines":
      "node": ">=8.4.0"
      ,
      "dependencies":
      "electron": "^4.0.8",
      "electron-rebuild": "^1.8.4"








      javascript c++ electron node.js-addon n-api






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Mar 9 at 1:02









      Raees RajwaniRaees Rajwani

      332313




      332313






















          1 Answer
          1






          active

          oldest

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          1














          The reason it blocks Electron is the sleep(10). That call doesn't return for 10 seconds.



          So yes, there is a way to offload heavy computation to another thread. The biggest complication from doing so is that the thread can't make a callback to JavaScript without taking extra precautions nor can the thread access JavaScript data structures, so it must be provided with all the data necessary.



          Here's the example the C++ abstraction provides for N-API using a thread to calculate Pi.



          node-addon-example



          And here are C++ wrappers to create thread-safe callbacks.



          napi-threadsafe-callback



          It's not trivial but these two examples should get you through it.






          share|improve this answer























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            1 Answer
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            active

            oldest

            votes






            active

            oldest

            votes









            1














            The reason it blocks Electron is the sleep(10). That call doesn't return for 10 seconds.



            So yes, there is a way to offload heavy computation to another thread. The biggest complication from doing so is that the thread can't make a callback to JavaScript without taking extra precautions nor can the thread access JavaScript data structures, so it must be provided with all the data necessary.



            Here's the example the C++ abstraction provides for N-API using a thread to calculate Pi.



            node-addon-example



            And here are C++ wrappers to create thread-safe callbacks.



            napi-threadsafe-callback



            It's not trivial but these two examples should get you through it.






            share|improve this answer



























              1














              The reason it blocks Electron is the sleep(10). That call doesn't return for 10 seconds.



              So yes, there is a way to offload heavy computation to another thread. The biggest complication from doing so is that the thread can't make a callback to JavaScript without taking extra precautions nor can the thread access JavaScript data structures, so it must be provided with all the data necessary.



              Here's the example the C++ abstraction provides for N-API using a thread to calculate Pi.



              node-addon-example



              And here are C++ wrappers to create thread-safe callbacks.



              napi-threadsafe-callback



              It's not trivial but these two examples should get you through it.






              share|improve this answer

























                1












                1








                1







                The reason it blocks Electron is the sleep(10). That call doesn't return for 10 seconds.



                So yes, there is a way to offload heavy computation to another thread. The biggest complication from doing so is that the thread can't make a callback to JavaScript without taking extra precautions nor can the thread access JavaScript data structures, so it must be provided with all the data necessary.



                Here's the example the C++ abstraction provides for N-API using a thread to calculate Pi.



                node-addon-example



                And here are C++ wrappers to create thread-safe callbacks.



                napi-threadsafe-callback



                It's not trivial but these two examples should get you through it.






                share|improve this answer













                The reason it blocks Electron is the sleep(10). That call doesn't return for 10 seconds.



                So yes, there is a way to offload heavy computation to another thread. The biggest complication from doing so is that the thread can't make a callback to JavaScript without taking extra precautions nor can the thread access JavaScript data structures, so it must be provided with all the data necessary.



                Here's the example the C++ abstraction provides for N-API using a thread to calculate Pi.



                node-addon-example



                And here are C++ wrappers to create thread-safe callbacks.



                napi-threadsafe-callback



                It's not trivial but these two examples should get you through it.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Mar 12 at 11:40









                bmacnaughtonbmacnaughton

                2,77211728




                2,77211728





























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