Update charted to 0.4.8 and roll

packages/intl/lib/message_lookup_by_library.dart

Index: packages/intl/lib/message_lookup_by_library.dart
diff --git a/packages/intl/lib/message_lookup_by_library.dart b/packages/intl/lib/message_lookup_by_library.dart
index 3b668d4cdf4f8eb58fd237072fb7bd15a3c235ed..7ef2a8d607504135b3caf7ab9f5d3c00bc0cf2e9 100644
--- a/packages/intl/lib/message_lookup_by_library.dart
+++ b/packages/intl/lib/message_lookup_by_library.dart
@@ -2,113 +2,142 @@
 // 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.
 
-/**
- * Message/plural format library with locale support. This can have different
- * implementations based on the mechanism for finding the localized versions
- * of messages. This version expects them to be in a library named e.g.
- * 'messages_en_US'. The prefix is set in the "initializeMessages" call, which
- * must be made for a locale before any lookups can be done.
- *
- * See Intl class comment or `tests/message_format_test.dart` for more examples.
- */
+/// Message/plural format library with locale support. This can have different
+/// implementations based on the mechanism for finding the localized versions of
+/// messages. This version expects them to be in a library named e.g.
+/// 'messages_en_US'. The prefix is set in the "initializeMessages" call, which
+/// must be made for a locale before any lookups can be done.
+///
+/// See Intl class comment or `tests/message_format_test.dart` for more
+/// examples.
 library message_lookup_by_library;
 
-import 'intl.dart';
+import 'package:intl/intl.dart';
+import 'package:intl/src/intl_helpers.dart';
 
-/**
- * This is a message lookup mechanism that delegates to one of a collection
- * of individual [MessageLookupByLibrary] instances.
- */
-class CompositeMessageLookup {
-  /** A map from locale names to the corresponding lookups. */
+/// This is a message lookup mechanism that delegates to one of a collection
+/// of individual [MessageLookupByLibrary] instances.
+class CompositeMessageLookup implements MessageLookup {
+  /// A map from locale names to the corresponding lookups.
   Map<String, MessageLookupByLibrary> availableMessages = new Map();
 
-  /** Return true if we have a message lookup for [localeName]. */
+  /// Return true if we have a message lookup for [localeName].
   bool localeExists(localeName) => availableMessages.containsKey(localeName);
 
-  /**
-   * Look up the message with the given [name] and [locale] and return
-   * the translated version with the values in [args] interpolated.
-   * If nothing is found, return [message_str]. The [desc] and [examples]
-   * parameters are ignored
-   */
-  String lookupMessage(String message_str, [final String desc = '',
-      final Map examples = const {}, String locale, String name,
-      List<String> args, String meaning]) {
-    var actualLocale = (locale == null) ? Intl.getCurrentLocale() : locale;
-    // For this usage, if the locale doesn't exist for messages, just return
-    // it and we'll fall back to the original version.
-    var verifiedLocale = Intl.verifiedLocale(actualLocale, localeExists,
+  /// The last locale in which we looked up messages.
+  ///
+  ///  If this locale matches the new one then we can skip looking up the
+  ///  messages and assume they will be the same as last time.
+  String _lastLocale;
+
+  /// Caches the last messages that we found
+  MessageLookupByLibrary _lastLookup;
+
+  /// Look up the message with the given [name] and [locale] and return
+  /// the translated version with the values in [args] interpolated.
+  /// If nothing is found, return [message_str]. The [desc] and [examples]
+  /// parameters are ignored
+  String lookupMessage(
+      String message_str, String locale, String name, List args, String meaning,
+      {MessageIfAbsent ifAbsent: _useOriginal}) {
+    // If passed null, use the default.
+    var knownLocale = locale ?? Intl.getCurrentLocale();
+    var messages = (knownLocale == _lastLocale)
+        ? _lastLookup
+        : _lookupMessageCatalog(knownLocale);
+    // If we didn't find any messages for this locale, use the original string,
+    // faking interpolations if necessary.
+    if (messages == null) {
+      return ifAbsent(message_str, args);
+    }
+    return messages.lookupMessage(message_str, locale, name, args, meaning,
+        ifAbsent: ifAbsent);
+  }
+
+  /// Find the right message lookup for [locale].
+  MessageLookupByLibrary _lookupMessageCatalog(String locale) {
+    var verifiedLocale = Intl.verifiedLocale(locale, localeExists,
         onFailure: (locale) => locale);
-    var messages = availableMessages[verifiedLocale];
-    if (messages == null) return message_str;
-    return messages.lookupMessage(
-        message_str, desc, examples, locale, name, args, meaning);
+    _lastLocale = locale;
+    _lastLookup = availableMessages[verifiedLocale];
+    return _lastLookup;
   }
 
-  /**
-   * If we do not already have a locale for [localeName] then
-   * [findLocale] will be called and the result stored as the lookup
-   * mechanism for that locale.
-   */
-  addLocale(String localeName, Function findLocale) {
+  /// If we do not already have a locale for [localeName] then
+  /// [findLocale] will be called and the result stored as the lookup
+  /// mechanism for that locale.
+  void addLocale(String localeName, Function findLocale) {
     if (localeExists(localeName)) return;
     var canonical = Intl.canonicalizedLocale(localeName);
     var newLocale = findLocale(canonical);
     if (newLocale != null) {
       availableMessages[localeName] = newLocale;
       availableMessages[canonical] = newLocale;
+      // If there was already a failed lookup for [newLocale], null the cache.
+      if (_lastLocale == newLocale) {
+        _lastLocale = null;
+        _lastLookup = null;
+      }
     }
   }
 }
 
-/**
- * This provides an abstract class for messages looked up in generated code.
- * Each locale will have a separate subclass of this class with its set of
- * messages. See generate_localized.dart.
- */
+/// The default ifAbsent method, just returns the message string.
+String _useOriginal(String message_str, List args) => message_str;
+
+/// This provides an abstract class for messages looked up in generated code.
+/// Each locale will have a separate subclass of this class with its set of
+/// messages. See generate_localized.dart.
 abstract class MessageLookupByLibrary {
-  /**
-   * Return the localized version of a message. We are passed the original
-   * version of the message, which consists of a
-   * [message_str] that will be translated, and which may be interpolated
-   * based on one or more variables, a [desc] providing a description of usage
-   * for the [message_str], and a map of [examples] for each data element to be
-   * substituted into the message.
-   *
-   * For example, if message="Hello, $name", then
-   * examples = {'name': 'Sparky'}. If not using the user's default locale, or
-   * if the locale is not easily detectable, explicitly pass [locale].
-   *
-   * The values of [desc] and [examples] are not used at run-time but are only
-   * made available to the translators, so they MUST be simple Strings available
-   * at compile time: no String interpolation or concatenation.
-   * The expected usage of this is inside a function that takes as parameters
-   * the variables used in the interpolated string.
-   *
-   * Ultimately, the information about the enclosing function and its arguments
-   * will be extracted automatically but for the time being it must be passed
-   * explicitly in the [name] and [args] arguments.
-   */
-  String lookupMessage(String message_str, [final String desc = '',
-      final Map examples = const {}, String locale, String name,
-      List<String> args, String meaning]) {
-    if (name == null) return message_str;
-    var function = this[name];
-    return function == null ? message_str : Function.apply(function, args);
+  /// Return the localized version of a message. We are passed the original
+  /// version of the message, which consists of a
+  /// [message_str] that will be translated, and which may be interpolated
+  /// based on one or more variables, a [desc] providing a description of usage
+  /// for the [message_str], and a map of [examples] for each data element to be
+  /// substituted into the message.
+  ///
+  /// For example, if message="Hello, $name", then
+  /// examples = {'name': 'Sparky'}. If not using the user's default locale, or
+  /// if the locale is not easily detectable, explicitly pass [locale].
+  ///
+  /// The values of [desc] and [examples] are not used at run-time but are only
+  /// made available to the translators, so they MUST be simple Strings
+  /// available at compile time: no String interpolation or concatenation.  The
+  /// expected usage of this is inside a function that takes as parameters the
+  /// variables used in the interpolated string.
+  ///
+  /// Ultimately, the information about the enclosing function and its arguments
+  /// will be extracted automatically but for the time being it must be passed
+  /// explicitly in the [name] and [args] arguments.
+  String lookupMessage(
+      String message_str, String locale, String name, List args, String meaning,
+      {MessageIfAbsent ifAbsent}) {
+    var notFound = false;
+    var actualName = computeMessageName(name, message_str, meaning);
+    if (actualName == null) notFound = true;
+    var function = this[actualName];
+    notFound = notFound || (function == null);
+    if (notFound) {
+      return ifAbsent == null ? message_str : ifAbsent(message_str, args);
+    } else {
+      args = args ?? [];
+      return Function.apply(function, args);
+    }
   }
 
-  /** Return our message with the given name */
+  /// Return our message with the given name
   operator [](String messageName) => messages[messageName];
 
-  /**
-   * Subclasses should override this to return a list of their message
-   * functions.
-   */
+  /// Subclasses should override this to return a list of their message
+  /// functions.
   Map<String, Function> get messages;
 
-  /** Subclasses should override this to return their locale, e.g. 'en_US' */
+  /// Subclasses should override this to return their locale, e.g. 'en_US'
   String get localeName;
 
   toString() => localeName;
+
+  /// Return a function that returns the given string.
+  /// An optimization for dart2js, used from the generated code.
+  static simpleMessage(translatedString) => () => translatedString;
 }