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packages/intl/bin/generate_from_arb.dart

+#!/usr/bin/env dart
+// Copyright (c) 2013, 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 main program that takes as input a source Dart file and a number
+ * of ARB files representing translations of messages from the corresponding
+ * Dart file. See extract_to_arb.dart and make_hardcoded_translation.dart.
+ *
+ * This produces a series of files named
+ * "messages_<locale>.dart" containing messages for a particular locale
+ * and a main import file named "messages_all.dart" which has imports all of
+ * them and provides an initializeMessages function.
+ */
+library generate_from_arb;
+
+import 'dart:convert';
+import 'dart:io';
+import 'package:intl/extract_messages.dart';
+import 'package:intl/src/icu_parser.dart';
+import 'package:intl/src/intl_message.dart';
+import 'package:intl/generate_localized.dart';
+import 'package:path/path.dart' as path;
+import 'package:args/args.dart';
+
+/**
+ * Keeps track of all the messages we have processed so far, keyed by message
+ * name.
+ */
+Map<String, List<MainMessage>> messages;
+
+main(List<String> args) {
+  var targetDir;
+  var parser = new ArgParser();
+  parser.addFlag("suppress-warnings",
+      defaultsTo: false,
+      callback: (x) => suppressWarnings = x,
+      help: 'Suppress printing of warnings.');
+  parser.addOption("output-dir",
+      defaultsTo: '.',
+      callback: (x) => targetDir = x,
+      help: 'Specify the output directory.');
+  parser.addOption("generated-file-prefix",
+      defaultsTo: '',
+      callback: (x) => generatedFilePrefix = x,
+      help: 'Specify a prefix to be used for the generated file names.');
+  parser.addFlag("use-deferred-loading",
+      defaultsTo: true,
+      callback: (x) => useDeferredLoading = x,
+      help: 'Generate message code that must be loaded with deferred loading. '
+      'Otherwise, all messages are eagerly loaded.');
+  parser.parse(args);
+  var dartFiles = args.where((x) => x.endsWith("dart")).toList();
+  var jsonFiles = args.where((x) => x.endsWith(".arb")).toList();
+  if (dartFiles.length == 0 || jsonFiles.length == 0) {
+    print('Usage: generate_from_arb [options]'
+        ' file1.dart file2.dart ...'
+        ' translation1_<languageTag>.arb translation2.arb ...');
+    print(parser.usage);
+    exit(0);
+  }
+
+  // We're re-parsing the original files to find the corresponding messages,
+  // so if there are warnings extracting the messages, suppress them.
+  suppressWarnings = true;
+  var allMessages = dartFiles.map((each) => parseFile(new File(each)));
+
+  messages = new Map();
+  for (var eachMap in allMessages) {
+    eachMap.forEach(
+        (key, value) => messages.putIfAbsent(key, () => []).add(value));
+  }
+  for (var arg in jsonFiles) {
+    var file = new File(arg);
+    generateLocaleFile(file, targetDir);
+  }
+
+  var mainImportFile =
+      new File(path.join(targetDir, '${generatedFilePrefix}messages_all.dart'));
+  mainImportFile.writeAsStringSync(generateMainImportFile());
+}
+
+/**
+ * Create the file of generated code for a particular locale. We read the ARB
+ * data and create [BasicTranslatedMessage] instances from everything,
+ * excluding only the special _locale attribute that we use to indicate the
+ * locale. If that attribute is missing, we try to get the locale from the last
+ * section of the file name.
+ */
+void generateLocaleFile(File file, String targetDir) {
+  var src = file.readAsStringSync();
+  var data = JSON.decode(src);
+  data.forEach((k, v) => data[k] = recreateIntlObjects(k, v));
+  var locale = data["_locale"];
+  if (locale != null) {
+    locale = locale.translated.string;
+  } else {
+    // Get the locale from the end of the file name. This assumes that the file
+    // name doesn't contain any underscores except to begin the language tag
+    // and to separate language from country. Otherwise we can't tell if
+    // my_file_fr.arb is locale "fr" or "file_fr".
+    var name = path.basenameWithoutExtension(file.path);
+    locale = name.split("_").skip(1).join("_");
+  }
+  allLocales.add(locale);
+
+  var translations = [];
+  data.forEach((key, value) {
+    if (value != null) {
+      translations.add(value);
+    }
+  });
+  generateIndividualMessageFile(locale, translations, targetDir);
+}
+
+/**
+ * Regenerate the original IntlMessage objects from the given [data]. For
+ * things that are messages, we expect [id] not to start with "@" and
+ * [data] to be a String. For metadata we expect [id] to start with "@"
+ * and [data] to be a Map or null. For metadata we return null.
+ */
+BasicTranslatedMessage recreateIntlObjects(String id, data) {
+  if (id.startsWith("@")) return null;
+  if (data == null) return null;
+  var parsed = pluralAndGenderParser.parse(data).value;
+  if (parsed is LiteralString && parsed.string.isEmpty) {
+    parsed = plainParser.parse(data).value;
+    ;
+  }
+  return new BasicTranslatedMessage(id, parsed);
+}
+
+/**
+ * A TranslatedMessage that just uses the name as the id and knows how to look
+ * up its original messages in our [messages].
+ */
+class BasicTranslatedMessage extends TranslatedMessage {
+  BasicTranslatedMessage(String name, translated) : super(name, translated);
+
+  List<MainMessage> get originalMessages => (super.originalMessages == null)
+      ? _findOriginals()
+      : super.originalMessages;
+
+  // We know that our [id] is the name of the message, which is used as the
+  //key in [messages].
+  List<MainMessage> _findOriginals() => originalMessages = messages[id];
+}
+
+final pluralAndGenderParser = new IcuParser().message;
+final plainParser = new IcuParser().nonIcuMessage;