Async initialization for DateFormat

pkg/intl/tools/generate_locale_data_files.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/**
+ * A utility program to take locale data represented as a Dart map whose keys
+ * are locale names and write it into individual JSON files named by locale.
+ * This should be run any time the locale data changes.
+ *
+ * The files are written under "data/dates", in two subdirectories, "symbols"
+ * and "patterns". In "data/dates" it will also generate "localeList.dart",
+ * which is sourced by the date_symbol_data... files.
+ */
+
+#import('../date_symbols.dart');
+#import('../date_symbol_data_local.dart');
+#import('../date_time_patterns.dart');
+#import('../date_format.dart');
+#import('dart:io');
+#import('dart:json');
+#import('../test/data_directory.dart');
+
+main() {
+  initializeDateFormatting("en_IGNORED", null);
+  writeSymbolData();
+  writePatternData();
+  // TODO(alanknight): Are the en_ISO patterns reliably the same as general en?
+  writePatterns("en_ISO", dateTimePatternMap()["en"]);
+  writeLocaleList();
+}
+
+void writeLocaleList() {
+  var file = new File('${dataDirectory}localeList.dart');
+  var outputStream = file.openOutputStream();
+  outputStream.writeString(
+      '// Copyright (c) 2012, the Dart project authors.  Please see the '
+      'AUTHORS file\n// for details. All rights reserved. Use of this source'
+      'code is governed by a\n// BSD-style license that can be found in the'
+      ' LICENSE file.\n\n'
+      '/// Hard-coded list of all available locales for dates.\n');
+  outputStream.writeString('final availableLocalesForDateFormatting = const [');
+  List<String> allLocales = DateFormat.allLocalesWithSymbols();
+  allLocales.forEach((locale) {
+    outputStream.writeString('"$locale"');
+    if (locale == allLocales.last()) {
+      outputStream.writeString('];');
+    } else {
+      outputStream.writeString(',\n    ');
+    }
+  });
+}
+
+void writeSymbolData() {
+  dateTimeSymbolMap().forEach(
+      (locale, symbols) => writeSymbols(locale, symbols));
+}
+
+void writePatternData() {
+  dateTimePatternMap().forEach(
+      (locale, patterns) => writePatterns(locale, patterns));
+}
+
+void writeSymbols(locale, symbols) {
+  var file = new File('${dataDirectory}symbols/${locale}.json');
+  var outputStream = file.openOutputStream();
+  writeToJSON(symbols, outputStream);
+  outputStream.close();
+}
+
+void writePatterns(locale, patterns) {
+  var file = new File('${dataDirectory}patterns/${locale}.json');
+  var outputStream = file.openOutputStream();
+  outputStream.writeString(JSON.stringify(patterns));
+  outputStream.close();
+}
+
+void writeToJSON(Dynamic data, OutputStream out) {
+  out.writeString(JSON.stringify(data.serializeToMap()));
+}