CmdRunWorker.js

var popen, fread, pclose;

var inited = false;

function init(platform) {
    var lib;
    if (platform == "X11" || platform == "Linux") {
        // https://developer.mozilla.org/en/js-ctypes/Using_js-ctypes#Calling_LibC_routines_on_Linux.2FPOSIX
        try {  
            /* Linux */  
            lib = ctypes.open("libc.so.6");  
        } catch (e) {  
            /* Most other Unixes */  
            try {
                lib = ctypes.open("libc.so");  
            } catch(err) {
                dump("Could not open libc at 'libc.so.6 or libc.so'\n");
                throw "Could not open libc at 'libc.so.6 or ibc.so'";
            }
        }  
    } else if (platform == "Macintosh"){
        lib = ctypes.open("/usr/lib/libc.dylib"); 
    } else if (platform == "Windows") {
        return;
    } else {
        dump("Unknown platform '"  + platform + "'\n");
        throw "Unknown platform: " + platform;
    }
    
    popen = lib.declare("popen",  
                         ctypes.default_abi,  
                         ctypes.voidptr_t,     // Return int
                         ctypes.char.ptr,       // Param1 const char *command
                         ctypes.char.ptr       // Param1 const char *command
                            );
                            
    fread = lib.declare("fread",  
                         ctypes.default_abi,  
                         ctypes.size_t,     // Return int
                         ctypes.voidptr_t,
                         ctypes.size_t,
                         ctypes.size_t,
                         ctypes.voidptr_t
                            );
                            
    pclose = lib.declare("pclose",  
                         ctypes.default_abi,  
                         ctypes.int,     // Return int
                         ctypes.voidptr_t
                            );
    inited = true;
}

self.onmessage = function (msg) {
  if (!inited) {
    init(msg.data.cmd);
    return;
  }

  var cmd = msg.data.cmd;
  if (msg.data.type === "runCommand") {
    var result = runCommandWorker(cmd, msg.data.isProgressive);
    self.postMessage({ cmd: cmd, result: result });
  } else if (msg.data.type === "platform") {
    // do nothing
  } else if (msg.data.type === "exec") {
    exec(cmd);
  } else {
    dump("Bad message type\n");
  }
}

function exec(cmd) {
    var file = popen(cmd, "r")
    pclose(file);
    return "";
}

function runCommandWorker(cmd, isProgressiveResult) {
    var file = popen(cmd, "r")
    
    const bufferSize = 1000;
    var buffer = ctypes.char.array(bufferSize)("");
    var size = bufferSize;
    var outList = [];
    while (size == bufferSize) {
        size = fread(buffer, 1, bufferSize, file);
        try {
            if (isProgressiveResult) {
                self.postMessage({ cmd: cmd, progress: buffer.readString().substring(0, size) });
            } else {
                outList.push(buffer.readString().substring(0, size));
            }
        } catch (e) {
            //dump("Exception reading line, ignoring characters.\n");
        }
    }
    pclose(file);
    
    return outList.join("");
}