js: support spawn jsapi

js/README.md

@@ -10,12 +10,12 @@ yarn add kernelsu
 
 ### exec
 
-Execute a command in the **root** shell.
+Spawns a **root** shell and runs a command within that shell, passing the `stdout` and `stderr` to a Promise when complete.
 
-options:
-
-- `cwd` - Current working directory of the child process
-- `env` - Environment key-value pairs
+- `command` `<string>` The command to run, with space-separated arguments.
+- `options` `<Object>`
+  - `cwd` - Current working directory of the child process
+  - `env` - Environment key-value pairs
 
 ```javascript
 import { exec } from 'kernelsu';
@@ -27,6 +27,71 @@ if (errno === 0) {
 }
 ```
 
+### spawn
+
+Spawns a new process using the given `command` in **root** shell, with command-line arguments in `args`. If omitted, `args` defaults to an empty array.
+
+Returns a `ChildProcess`, Instances of the ChildProcess represent spawned child processes.
+
+- `command` `<string>` The command to run.
+- `args` `<string[]>` List of string arguments.
+- `options` `<Object>`:
+  - `cwd` `<string>` - Current working directory of the child process
+  - `env` `<Object>` - Environment key-value pairs
+
+Example of running `ls -lh /data`, capturing `stdout`, `stderr`, and the exit code:
+
+```javascript
+import { spawn } from 'kernelsu';
+
+const ls = spawn('ls', ['-lh', '/data']);
+
+ls.stdout.on('data', (data) => {
+  console.log(`stdout: ${data}`);
+});
+
+ls.stderr.on('data', (data) => {
+  console.log(`stderr: ${data}`);
+});
+
+ls.on('exit', (code) => {
+  console.log(`child process exited with code ${code}`);
+});
+```
+
+#### ChildProcess
+
+##### Event 'exit'
+
+- `code` `<number>` The exit code if the child exited on its own.
+
+The `'exit'` event is emitted after the child process ends. If the process exited, `code` is the final exit code of the process, otherwise null
+
+##### Event 'error'
+
+- `err` `<Error>` The error.
+
+The `'error'` event is emitted whenever:
+
+- The process could not be spawned.
+- The process could not be killed.
+
+##### `stdout`
+
+A `Readable Stream` that represents the child process's `stdout`.
+
+```javascript
+const subprocess = spawn('ls');
+
+subprocess.stdout.on('data', (data) => {
+  console.log(`Received chunk ${data}`);
+});
+```
+
+#### `stderr`
+
+A `Readable Stream` that represents the child process's `stderr`.
+
 ### fullScreen
 
 Request the WebView enter/exit full screen.

js/index.js

@@ -1,6 +1,6 @@
 let callbackCounter = 0;
-function getUniqueCallbackName() {
-  return `_callback_${Date.now()}_${callbackCounter++}`;
+function getUniqueCallbackName(prefix) {
+  return `${prefix}_callback_${Date.now()}_${callbackCounter++}`;
 }
 
 export function exec(command, options) {
@@ -10,7 +10,7 @@ export function exec(command, options) {
 
   return new Promise((resolve, reject) => {
     // Generate a unique callback function name
-    const callbackFuncName = getUniqueCallbackName();
+    const callbackFuncName = getUniqueCallbackName("exec");
 
     // Define the success callback function
     window[callbackFuncName] = (errno, stdout, stderr) => {
@@ -23,11 +23,7 @@ export function exec(command, options) {
     }
 
     try {
-      ksu.exec(
-        command,
-        JSON.stringify(options),
-        callbackFuncName,
-      );
+      ksu.exec(command, JSON.stringify(options), callbackFuncName);
     } catch (error) {
       reject(error);
       cleanup(callbackFuncName);
@@ -35,6 +31,73 @@ export function exec(command, options) {
   });
 }
 
+function Stdio() {
+    this.listeners = {};
+  }
+  
+  Stdio.prototype.on = function (event, listener) {
+    if (!this.listeners[event]) {
+      this.listeners[event] = [];
+    }
+    this.listeners[event].push(listener);
+  };
+  
+  Stdio.prototype.emit = function (event, ...args) {
+    if (this.listeners[event]) {
+      this.listeners[event].forEach((listener) => listener(...args));
+    }
+  };
+  
+  function ChildProcess() {
+    this.listeners = {};
+    this.stdin = new Stdio();
+    this.stdout = new Stdio();
+    this.stderr = new Stdio();
+  }
+  
+  ChildProcess.prototype.on = function (event, listener) {
+    if (!this.listeners[event]) {
+      this.listeners[event] = [];
+    }
+    this.listeners[event].push(listener);
+  };
+  
+  ChildProcess.prototype.emit = function (event, ...args) {
+    if (this.listeners[event]) {
+      this.listeners[event].forEach((listener) => listener(...args));
+    }
+  };
+  
+  export function spawn(command, args, options) {
+    if (typeof args === "undefined") {
+      args = [];
+    }
+    
+    if (typeof options === "undefined") {
+      options = {};
+    }
+  
+    const child = new ChildProcess();
+    const childCallbackName = getUniqueCallbackName("spawn");
+    window[childCallbackName] = child;
+  
+    function cleanup(name) {
+      delete window[name];
+    }
+    try {
+      ksu.spawn(
+        command,
+        JSON.stringify(args),
+        JSON.stringify(options),
+        childCallbackName
+      );
+    } catch (error) {
+      child.emit("error", error);
+      cleanup(childCallbackName);
+    }
+    return child;
+  }
+
 export function fullScreen(isFullScreen) {
   ksu.fullScreen(isFullScreen);
 }