Save language metadata on build to avoid readdirs later

src/languages.js

@@ -4,7 +4,7 @@ var fs = require('fs');
 var path = require('path');
 var async = require('async');
 
-var Languages = {};
+var Languages = module.exports;
 var	languagesPath = path.join(__dirname, '../build/public/language');
 
 Languages.init = function (next) {
@@ -27,10 +27,13 @@ Languages.get = function (language, namespace, callback) {
 	});
 };
 
-Languages.list = function (callback) {
-	var languages = [];
+var codeCache = null;
+Languages.listCodes = function (callback) {
+	if (codeCache && codeCache.length) {
+		return callback(null, codeCache);
+	}
 
-	fs.readdir(languagesPath, function (err, files) {
+	fs.readFile(path.join(languagesPath, 'metadata.json'), function (err, buffer) {
 		if (err && err.code === 'ENOENT') {
 			return callback(null, []);
 		}
@@ -38,43 +41,59 @@ Languages.list = function (callback) {
 			return callback(err);
 		}
 
-		async.each(files, function (folder, next) {
-			fs.stat(path.join(languagesPath, folder), function (err, stat) {
-				if (err) {
-					return next(err);
+		var parsed;
+		try {
+			parsed = JSON.parse(buffer.toString());
+		} catch (e) {
+			return callback(e);
 		}
 
-				if (!stat.isDirectory()) {
-					return next();
+		var langs = parsed.languages;
+		codeCache = langs;
+		callback(null, langs);
+	});
+};
+
+var listCache = null;
+Languages.list = function (callback) {
+	if (listCache && listCache.length) {
+		return callback(null, listCache);
 	}
 
+	Languages.listCodes(function (err, codes) {
+		if (err) {
+			return callback(err);
+		}
+
+		async.map(codes, function (folder, next) {
 			var configPath = path.join(languagesPath, folder, 'language.json');
 
 			fs.readFile(configPath, function (err, buffer) {
-					if (err && err.code !== 'ENOENT') {
+				if (err && err.code === 'ENOENT') {
+					return next();
+				}
+				if (err) {
 					return next(err);
 				}
-					if (buffer) {
+				try {
 					var lang = JSON.parse(buffer.toString());
-						if (lang.name && lang.code && lang.dir) {
-							languages.push(lang);
-						}
+					next(null, lang);
+				} catch (e) {
+					next(e);
 				}
-					next();
 			});
-			});
-		}, function (err) {
+		}, function (err, languages) {
 			if (err) {
 				return callback(err);
 			}
-			// Sort alphabetically
-			languages = languages.sort(function (a, b) {
-				return a.code > b.code ? 1 : -1;
+
+			// filter out invalid ones
+			languages = languages.filter(function (lang) {
+				return lang.code && lang.name && lang.dir;
 			});
 
-			callback(err, languages);
+			listCache = languages;
+			callback(null, languages);
 		});
 	});
 };
-
-module.exports = Languages;

src/meta/languages.js

@@ -102,6 +102,25 @@ function getTranslationTree(callback) {
 			});
 		},
 
+		// save a list of languages to `${buildLanguagesPath}/metadata.json`
+		// avoids readdirs later on
+		function (ref, next) {
+			async.waterfall([
+				function (next) {
+					mkdirp(buildLanguagesPath, next);
+				},
+				function (x, next) {
+					fs.writeFile(path.join(buildLanguagesPath, 'metadata.json'), JSON.stringify({
+						languages: ref.languages.sort(),
+						namespaces: ref.namespaces.sort(),
+					}), next);
+				},
+				function (next) {
+					next(null, ref);
+				},
+			], next);
+		},
+
 		// for each language and namespace combination,
 		// run through core and all plugins to generate
 		// a full translation hash