From c9432071700e8576ad532b6fadf78a3bb0f1f7ed Mon Sep 17 00:00:00 2001
From: Martin Eisenhardt <martin.eisenhardt@mneisen.org>
Date: Thu, 15 May 2008 17:06:33 +0200
Subject: [PATCH] Add convenience methods for time zones outside the US.

The TimeZone class in ActiveSupport includes a us_zones method to
conveniently create a collection of all time zones in the US. Now,
there are the additional methods african_zones, american_zones,
asian_zones, atlantic_zones, australian_zones, european_zones,
and pacific_zones which to the same for other regions of the world.

They all use the new method zones_by_regex(regex) which creates a list
of all TimeZone objects whose tzinfo matches the given regular
expression.

Furthermore, all new methods use caching; the collection of all - say -
European time zones is created upon class loading and stored away in
a constant. Subsequent invocations of european_zones will simply return
this pre-computed collection.

Signed-off-by: Martin Eisenhardt <martin.eisenhardt@mneisen.org>
---
 .../lib/active_support/values/time_zone.rb         |   91 ++++++++++++++++++++
 1 files changed, 91 insertions(+), 0 deletions(-)

diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
index f522b64..63f80fb 100644
--- a/activesupport/lib/active_support/values/time_zone.rb
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -330,6 +330,54 @@ class TimeZone
     US_ZONES.freeze
   end
 
+  # This method returns a collection of TimeZone objects with names
+  # matching the supplied regular expression.
+  def TimeZone.zones_by_regex(regex)
+    regex_zones = []
+    ZONES.each do |time_zone|
+      tzinfo_id = MAPPING[time_zone.name]
+      regex_zones << time_zone if tzinfo_id =~ regex
+    end
+
+    regex_zones
+  end
+
+  # Pre-compute the collection of time zones on the African continent.
+  unless const_defined?(:AFRICAN_ZONES)
+    AFRICAN_ZONES = zones_by_regex(/Africa/).sort!.freeze
+  end
+
+  # Pre-compute the collection of time zones on the American continent;
+  # this includes both North *and* South America.
+  unless const_defined?(:AMERICAN_ZONES)
+    AMERICAN_ZONES = zones_by_regex(/America/).sort!.freeze
+  end
+
+  # Pre-compute the collection of time zones on the Asian continent.
+  unless const_defined?(:ASIAN_ZONES)
+    ASIAN_ZONES = zones_by_regex(/Asia/).sort!.freeze
+  end
+
+  # Pre-compute the collection of time zones in the Atlantic ocean.
+  unless const_defined?(:ATLANTIC_ZONES)
+    ATLANTIC_ZONES = zones_by_regex(/Atlantic/).sort!.freeze
+  end
+
+  # Pre-compute the collection of time zones on the Australian continent.
+  unless const_defined?(:AUSTRALIAN_ZONES)
+    AUSTRALIAN_ZONES = zones_by_regex(/Australia/).sort!.freeze
+  end
+
+  # Pre-compute the collection of time zones on the European continent.
+  unless const_defined?(:EUROPEAN_ZONES)
+    EUROPEAN_ZONES = zones_by_regex(/Europe/).sort!.freeze
+  end
+
+  # Pre-compute the collection of time zones in the Pacific ocean.
+  unless const_defined?(:PACIFIC_ZONES)
+    PACIFIC_ZONES = zones_by_regex(/Pacific/).sort!.freeze
+  end
+
   class << self
     alias_method :create, :new
 
@@ -369,5 +417,48 @@ class TimeZone
     def us_zones
       US_ZONES
     end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in Africa.
+    def african_zones
+      AFRICAN_ZONES
+    end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in the Americas; this includes *both* North and South
+    # America.
+    def american_zones
+      AMERICAN_ZONES
+    end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in Asia.
+    def asian_zones
+      ASIAN_ZONES
+    end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in the Atlantic Ocean.
+    def atlantic_zones
+      ATLANTIC_ZONES
+    end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in Australia.
+    def australian_zones
+      AUSTRALIAN_ZONES
+    end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in Europe.
+    def european_zones
+      EUROPEAN_ZONES
+    end
+
+    # A convenience method for returning a collection of TimeZone objects
+    # for time zones in the Pacific ocean.
+    def pacific_zones
+      PACIFIC_ZONES
+    end
   end
 end
-- 
1.5.2.5