Build task for driving the compiler

package.json

@@ -15,7 +15,7 @@
     "url": "https://github.com/openlayers/ol3/issues"
   },
   "devDependencies": {
-    "closure-util": "~0.9.0",
+    "closure-util": "~0.10.0",
     "async": "~0.2.10",
     "htmlparser2": "~3.7.1",
     "jshint": "~2.4.4",

tasks/build.js

@@ -0,0 +1,137 @@
+/**
+ * This task builds OpenLayers with the Closure Compiler.
+ */
+var fs = require('fs');
+var path = require('path');
+
+var async = require('async');
+var closure = require('closure-util');
+var fse = require('fs-extra');
+
+var generateExports = require('./generate-exports');
+
+var log = closure.log;
+var root = path.join(__dirname, '..');
+
+
+/**
+ * Assert that a provided config object is valid.
+ * @param {Object} config Build configuration object.
+ * @param {function(Error)} callback Called with an error if config is invalid.
+ */
+function assertValidConfig(config, callback) {
+  process.nextTick(function() {
+    if (!Array.isArray(config.exports)) {
+      callback(new Error('Config missing "exports" array'));
+      return;
+    }
+    if (typeof config.compile !== 'object') {
+      callback(new Error('Config missing "compile" object'));
+      return;
+    }
+    callback(null);
+  });
+}
+
+
+/**
+ * Read the build configuration file.
+ * @param {string} configPath Path to config file.
+ * @param {function(Error, Object)} callback Callback.
+ */
+function readConfig(configPath, callback) {
+  fs.readFile(configPath, function(err, data) {
+    if (err) {
+      if (err.code === 'ENOENT') {
+        err = new Error('Unable to find config file: ' + configPath);
+      }
+      callback(err);
+      return;
+    }
+    var config;
+    try {
+      config = JSON.parse(String(data));
+    } catch (err2) {
+      callback(new Error('Trouble parsing config as JSON: ' + err2.message));
+      return;
+    }
+    callback(null, config);
+  });
+}
+
+
+/**
+ * Get the list of sources sorted in dependency order.
+ * @param {function(Error, Array.<string>)} callback Called with a list of paths
+ *     or any error.
+ */
+function getDependencies(callback) {
+  log.info('ol', 'Parsing dependencies ...');
+  closure.getDependencies({lib: ['src/**/*.js']}, function(err, paths) {
+    if (err) {
+      callback(err);
+      return;
+    }
+    paths.push(path.join(root, 'build', 'exports.js'));
+    callback(null, paths);
+  });
+}
+
+
+/**
+ * Run the compiler.
+ * @param {Object} options Options for Closure Compiler.
+ * @param {Array.<string>} paths List of paths to source files.
+ * @param {function(Error, string)} callback Called with the compiled output or
+ *     any error.
+ */
+function build(options, paths, callback) {
+  log.info('ol', 'Compiling ...');
+  options.js = paths;
+  closure.compile(options, callback);
+}
+
+
+/**
+ * Generate a build of the library.
+ * @param {Object} config Build configuration object.  Must have an "exports"
+ *     array and a "compile" object with options for the compiler.
+ * @param {function(Error, string)} callback Called with the compiled source
+ *     or any error.
+ */
+function main(config, callback) {
+  async.waterfall([
+    assertValidConfig.bind(null, config),
+    generateExports.bind(null, config.exports),
+    getDependencies,
+    build.bind(null, config.compile)
+  ], callback);
+}
+
+
+/**
+ * If running this module directly, read the config file and call the main
+ * function.
+ */
+if (require.main === module) {
+  var configPath = process.argv[2];
+  var outputPath = process.argv[3];
+  async.waterfall([
+    readConfig.bind(null, configPath),
+    main,
+    fse.outputFile.bind(fse, outputPath)
+  ], function(err) {
+    if (err) {
+      log.error(err.message);
+      process.exit(1);
+    } else {
+      process.exit(0);
+    }
+  });
+}
+
+
+/**
+ * Export main function.
+ */
+module.exports = main;