Implement writing by spawning the CLI as a child process (#385)

Signed-off-by: Juan Cruz Viotti <jviottidc@gmail.com>

lib/gui/modules/image-writer.js

@@ -21,13 +21,10 @@
  */
 
 const angular = require('angular');
+const _ = require('lodash');
 const electron = require('electron');
-
-if (window.mocha) {
-  var writer = electron.remote.require(require('path').join(__dirname, '..', '..', 'src', 'writer'));
-} else {
-  var writer = electron.remote.require('./src/writer');
-}
+const childProcess = require('child_process');
+const EXIT_CODES = require('../../src/exit-codes');
 
 const MODULE_NAME = 'Etcher.image-writer';
 const imageWriter = angular.module(MODULE_NAME, [
@@ -107,6 +104,7 @@ imageWriter.service('ImageWriterService', function($q, $timeout, SettingsModel,
    * @param {Object} drive - drive
    * @param {Function} onProgress - in progress callback (state)
    *
+   * @fulfil {Boolean} - whether the operation succeeded
    * @returns {Promise}
    *
    * @example
@@ -117,7 +115,72 @@ imageWriter.service('ImageWriterService', function($q, $timeout, SettingsModel,
    * });
    */
   this.performWrite = function(image, drive, onProgress) {
-    return $q.when(writer.writeImage(image, drive, SettingsModel.data, onProgress));
+    const argv = _.clone(electron.remote.process.argv);
+
+    argv.push(image);
+    argv.push('--drive', drive.device);
+    argv.push('--robot');
+
+    // Explicitly set the boolen flag in positive
+    // or negative way in order to be on the safe
+    // side in case the Etcher CLI changes the
+    // default value of these options.
+
+    if (SettingsModel.data.unmountOnSuccess) {
+      argv.push('--unmount');
+    } else {
+      argv.push('--no-unmount');
+    }
+
+    if (SettingsModel.data.validateWriteOnSuccess) {
+      argv.push('--check');
+    } else {
+      argv.push('--no-check');
+    }
+
+    return $q(function(resolve, reject) {
+      const child = childProcess.spawn(argv[0], argv.slice(1), {
+        env: {
+
+          // This environment variable tells Etcher to run
+          // in CLI mode. See `lib.start.js`.
+          ELECTRON_RUN_AS_NODE: 1
+
+        }
+      });
+
+      child.stderr.on('data', function(data) {
+        child.kill();
+        reject(new Error(data));
+      });
+
+      child.stdout.on('data', function(data) {
+        const information = data.toString().split(' ');
+
+        if (information[0] === 'progress') {
+          return onProgress({
+            type: information[1],
+            percentage: _.parseInt(information[2]),
+            eta: _.parseInt(information[3]),
+            speed: _.parseInt(information[4])
+          });
+        }
+      });
+
+      child.on('error', reject);
+
+      child.on('close', function(code) {
+        if (code === EXIT_CODES.SUCCESS) {
+          return resolve(true);
+        }
+
+        if (code === EXIT_CODES.VALIDATION_ERROR) {
+          return resolve(false);
+        }
+
+        return reject(new Error(`Child process exitted with error code: ${code}`));
+      });
+    });
   };
 
   /**
@@ -154,7 +217,7 @@ imageWriter.service('ImageWriterService', function($q, $timeout, SettingsModel,
 
         self.state = {
           type: state.type,
-          progress: Math.floor(state.percentage),
+          progress: state.percentage,
 
           // Transform bytes to megabytes preserving only two decimal places
           speed: Math.floor(state.speed / 1e+6 * 100) / 100 || 0

package.json

@@ -55,6 +55,7 @@
     "bootstrap-sass": "^3.3.5",
     "chalk": "^1.1.3",
     "drivelist": "^3.0.0",
+    "etcher-image-stream": "^1.2.0",
     "etcher-image-write": "^4.0.2",
     "flexboxgrid": "^6.3.0",
     "is-elevated": "^1.0.0",