feat(build): auto format the generated dart code.

Fixes #480
Closes #504

gulpfile.js

@@ -13,6 +13,7 @@ var pubbuild = require('./tools/build/pubbuild');
 var dartanalyzer = require('./tools/build/dartanalyzer');
 var jsserve = require('./tools/build/jsserve');
 var pubserve = require('./tools/build/pubserve');
+var rundartpackage = require('./tools/build/rundartpackage');
 var karma = require('karma').server;
 var minimist = require('minimist');
 
@@ -166,6 +167,10 @@ var CONFIG = {
   },
   pubspec: {
     src: 'modules/*/pubspec.yaml'
+  },
+  formatDart: {
+    packageName: 'dart_style',
+    args: ['dart_style:format', '-w', 'dist/dart']
   }
 };
 
@@ -310,6 +315,15 @@ gulp.task('build/pubbuild.dart', pubbuild(gulp, gulpPlugins, {
   command: DART_SDK.PUB
 }));
 
+// ------------
+// format dart
+
+gulp.task('build/format.dart', rundartpackage(gulp, gulpPlugins, {
+  pub: DART_SDK.PUB,
+  packageName: CONFIG.formatDart.packageName,
+  args: CONFIG.formatDart.args
+}));
+
 // ------------------
 // web servers
 gulp.task('serve.js.dev', jsserve(gulp, gulpPlugins, {
@@ -430,7 +444,8 @@ gulp.task('build.dart', function() {
     ['build/deps.js.dart2js', 'build/transpile.dart', 'build/html.dart'],
     'build/pubspec.dart',
     'build/pubbuild.dart',
-    'build/analyze.dart'
+    'build/analyze.dart',
+    'build/format.dart'
   );
 });
 

tools/build/rundartpackage.js

@@ -0,0 +1,44 @@
+var util = require('./util');
+var Q = require('q');
+var spawn = require('child_process').spawn;
+var readline = require('readline');
+
+module.exports = function(gulp, plugins, config) {
+  return function() {
+    return isInstalled().then(function(installed) {
+      if (!installed) {
+        return util.processToPromise(spawn(config.pub,
+          ['global', 'activate', config.packageName, '--no-executables'], {
+          stdio: 'inherit'
+        }));
+      }
+    }).then(function() {
+      return util.processToPromise(spawn(config.pub, ['global', 'run'].concat(config.args), {
+        stdio: 'inherit'
+      }));
+    });
+  };
+
+  function isInstalled() {
+    var subProcess = spawn(config.pub, ['global', 'list'], {
+      // inherit stdin and stderr, but filter stdout
+      stdio: [process.stdin, 'pipe', process.stderr]
+    });
+    var rl = readline.createInterface({
+      input: subProcess.stdout,
+      output: process.stdout,
+      terminal: false
+    });
+    var found = false;
+    rl.on('line', function(line) {
+      if (line.indexOf(config.packageName) !== -1) {
+        found = true;
+      }
+      console.log(line);
+    });
+    return util.processToPromise(subProcess).then( function() {
+      return found;
+    });
+  }
+
+};