Introduce ActiveSupport::TimeWithZone, for wrapping Time instances with a TimeZone. Introduce instance methods to Time for creating TimeWithZone instances, and class methods for managing a global time zone

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8696 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

7 files changed, 444 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 53ae421131..fa3e94dbf2 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Introduce ActiveSupport::TimeWithZone, for wrapping Time instances with a TimeZone. Introduce instance methods to Time for creating TimeWithZone instances, and class methods for managing a global time zone. [Geoff Buesing]
+
 * Replace non-dst-aware TimeZone class with dst-aware class from tzinfo_timezone plugin. TimeZone#adjust and #unadjust are no longer available; tzinfo gem must now be present in order to perform time zone calculations, via #local_to_utc and #utc_to_local methods. [Geoff Buesing]
 
 * Extract ActiveSupport::Callbacks from Active Record, test case setup and teardown, and ActionController::Dispatcher.  #10727 [Josh Peek]
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index 7a0476b729..4d2f873a8d 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -50,3 +50,5 @@ require 'active_support/json'
 require 'active_support/multibyte'
 
 require 'active_support/base64'
+
+require 'active_support/time_with_zone'
diff --git a/activesupport/lib/active_support/core_ext/date_time.rb b/activesupport/lib/active_support/core_ext/date_time.rb
index 1d711de70b..66a93eac43 100644
--- a/activesupport/lib/active_support/core_ext/date_time.rb
+++ b/activesupport/lib/active_support/core_ext/date_time.rb
@@ -1,10 +1,12 @@
 require 'date'
 require 'active_support/core_ext/time/behavior'
+require 'active_support/core_ext/time/zones'
 require 'active_support/core_ext/date_time/calculations'
 require 'active_support/core_ext/date_time/conversions'
 
 class DateTime
   include ActiveSupport::CoreExtensions::Time::Behavior
+  include ActiveSupport::CoreExtensions::Time::Zones
   include ActiveSupport::CoreExtensions::DateTime::Calculations
   include ActiveSupport::CoreExtensions::DateTime::Conversions
 end
diff --git a/activesupport/lib/active_support/core_ext/time.rb b/activesupport/lib/active_support/core_ext/time.rb
index d87c4ec65a..ea50511a96 100644
--- a/activesupport/lib/active_support/core_ext/time.rb
+++ b/activesupport/lib/active_support/core_ext/time.rb
@@ -11,9 +11,11 @@ end
 require 'active_support/core_ext/time/behavior'
 require 'active_support/core_ext/time/calculations'
 require 'active_support/core_ext/time/conversions'
+require 'active_support/core_ext/time/zones'
 
 class Time#:nodoc:
   include ActiveSupport::CoreExtensions::Time::Behavior
   include ActiveSupport::CoreExtensions::Time::Calculations
   include ActiveSupport::CoreExtensions::Time::Conversions
+  include ActiveSupport::CoreExtensions::Time::Zones
 end
diff --git a/activesupport/lib/active_support/core_ext/time/zones.rb b/activesupport/lib/active_support/core_ext/time/zones.rb
new file mode 100644
index 0000000000..563d522d9a
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/time/zones.rb
@@ -0,0 +1,68 @@
+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module Time #:nodoc:
+      # Methods for creating TimeWithZone objects from Time instances
+      module Zones
+        
+        def self.included(base) #:nodoc:
+          base.extend(ClassMethods) if base == ::Time # i.e., don't include class methods in DateTime
+        end
+        
+        module ClassMethods
+          attr_reader :zone
+
+          # Sets a global default time zone, separate from the system time zone in ENV['TZ']. 
+          # Accepts either a Rails TimeZone object, a string that identifies a 
+          # Rails TimeZone object (e.g., "Central Time (US & Canada)"), or a TZInfo::Timezone object
+          #
+          # Any Time or DateTime object can use this default time zone, via #in_current_time_zone.
+          # Example:
+          #
+          #   Time.zone = 'Hawaii'                  # => 'Hawaii'
+          #   Time.utc(2000).in_current_time_zone   # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+          def zone=(zone)
+            @zone = get_zone(zone)
+          end
+          
+          def zone_reset!
+            @zone = nil
+          end
+          
+          def get_zone(zone)
+            ::String === zone || ::Numeric === zone ? TimeZone[zone] : zone
+          end
+        end
+        
+        # Gives the corresponding time in the supplied zone. self is assumed to be in UTC regardless of constructor.
+        #
+        # Examples:
+        #
+        #   t = Time.utc(2000)        # => Sat Jan 01 00:00:00 UTC 2000
+        #   t.in_time_zone('Alaska')  # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
+        #   t.in_time_zone('Hawaii')  # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+        def in_time_zone(zone)
+          ActiveSupport::TimeWithZone.new(self, ::Time.get_zone(zone))
+        end
+
+        # Returns the simultaneous time in Time.zone
+        def in_current_time_zone
+          in_time_zone(::Time.zone)
+        end
+
+        # Replaces the existing zone; leaves time value intact. Examples:
+        #
+        #   t = Time.utc(2000)            # => Sat Jan 01 00:00:00 UTC 2000
+        #   t.change_time_zone('Alaska')  # => Sat, 01 Jan 2000 00:00:00 AKST -09:00
+        #   t.change_time_zone('Hawaii')  # => Sat, 01 Jan 2000 00:00:00 HST -10:00
+        def change_time_zone(zone)
+          ActiveSupport::TimeWithZone.new(nil, ::Time.get_zone(zone), self)
+        end
+
+        # Replaces the existing zone to Time.zone; leaves time value intact
+        def change_time_zone_to_current
+          change_time_zone(::Time.zone)
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
new file mode 100644
index 0000000000..dcd55ae93d
--- /dev/null
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -0,0 +1,156 @@
+module ActiveSupport
+  # A Time-like class that can represent a time in any time zone. Necessary because standard Ruby Time instances are 
+  # limited to UTC and the system's ENV['TZ'] zone
+  class TimeWithZone
+    include Comparable
+    attr_reader :time_zone
+  
+    def initialize(utc_time, time_zone = nil, local_time = nil)
+      @utc = utc_time
+      @time = local_time
+      @time_zone = time_zone
+    end
+  
+    # Returns a Time instance that represents the time in time_zone
+    def time
+      @time ||= utc? ? @utc : time_zone.utc_to_local(@utc)
+    end
+
+    # Returns a Time instance that represents the time in UTC
+    def utc
+      @utc ||= utc? ? @time : time_zone.local_to_utc(@time)
+    end
+    alias_method :comparable_time, :utc
+  
+    # Returns the underlying TZInfo::TimezonePeriod for the local time
+    def period
+      @period ||= get_period_for_local
+    end
+
+    # Returns the simultaneous time in the specified zone
+    def in_time_zone(new_zone)
+      utc.in_time_zone(new_zone)
+    end
+  
+    # Returns the simultaneous time in Time.zone
+    def in_current_time_zone
+      utc.in_current_time_zone
+    end
+  
+    # Changes the time zone without converting the time
+    def change_time_zone(new_zone)
+      time.change_time_zone(new_zone)
+    end
+  
+    # Changes the time zone to Time.zone without converting the time
+    def change_time_zone_to_current
+      time.change_time_zone_to_current
+    end
+  
+    # Returns a Time.local() instance of the simultaneous time in your system's ENV['TZ'] zone
+    def localtime
+      utc.dup.localtime # use #dup because Time#localtime is destructive
+    end
+  
+    def dst?
+      utc? ? false : period.dst?
+    end
+  
+    # The TimeZone class has no zone for UTC, so this class uses the absence of a time zone to indicate UTC
+    def utc?
+      !time_zone
+    end
+  
+    def utc_offset
+      utc? ? 0 : period.utc_total_offset
+    end
+  
+    def formatted_offset(colon = true, alternate_utc_string = nil)
+      utc? && alternate_utc_string || utc_offset.to_utc_offset_s(colon)
+    end
+  
+    # Time uses #zone to display the time zone abbreviation, so we're duck-typing it
+    def zone
+      utc? ? 'UTC' : period.abbreviation.to_s
+    end
+  
+    def inspect
+      "#{time.strftime('%a, %d %b %Y %H:%M:%S')} #{zone} #{formatted_offset}"
+    end
+
+    def xmlschema
+      "#{time.strftime("%Y-%m-%dT%H:%M:%S")}#{formatted_offset(true, 'Z')}"
+    end
+  
+    def to_json(options = nil)
+      %("#{time.strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)}")
+    end
+  
+    # :db format outputs time in UTC; all others output time in local. Uses TimeWithZone's strftime, so %Z and %z work correctly
+    def to_s(format = :default) 
+      return utc.to_s(format) if format == :db
+      if formatter = ::Time::DATE_FORMATS[format]
+        formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
+      else
+        "#{time.strftime("%Y-%m-%d %H:%M:%S")} #{formatted_offset(false, 'UTC')}" # mimicking Ruby 1.9 Time#to_s format
+      end
+    end
+    
+    # Replaces %Z and %z directives with #zone and #formatted_offset, respectively, before passing to 
+    # Time#strftime, so that zone information is correct
+    def strftime(format)
+      format = format.gsub('%Z', zone).gsub('%z', formatted_offset(false))
+      time.strftime(format)
+    end
+  
+    # Use the time in UTC for comparisons
+    def <=>(other)
+      other = other.comparable_time if other.respond_to?(:comparable_time) # to coerce time from TimeWithZone
+      utc <=> other
+    end
+  
+    # A TimeProxy acts like a Time, so just return self
+    def to_time
+      self
+    end
+    
+    # so that self acts_like?(:time)
+    def acts_like_time?
+      true
+    end
+  
+    # Say we're a Time to thwart type checking
+    def is_a?(klass)
+      klass == ::Time || super
+    end
+    alias_method :kind_of?, :is_a?
+  
+    # Neuter freeze because freezing can cause problems with lazy loading of attributes
+    def freeze
+      self
+    end
+  
+    # Ensure proxy class responds to all methods that underlying time instance responds to
+    def respond_to?(sym)
+      super || time.respond_to?(sym)
+    end
+  
+    # Send the missing method to time instance, and wrap result in a new TimeWithZone with the existing time_zone
+    def method_missing(sym, *args, &block)
+      result = time.__send__(sym, *args, &block)
+      result = result.change_time_zone(time_zone) if result.acts_like?(:time)
+      result
+    end
+  
+    private
+      def get_period_for_local
+        t = time
+        begin
+          time_zone.period_for_local(t, true)
+        rescue ::TZInfo::PeriodNotFound # failover logic from TzTime
+          t -= 1.hour
+          retry
+        end
+      end
+  end
+end
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
new file mode 100644
index 0000000000..5b0c0fd569
--- /dev/null
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -0,0 +1,212 @@
+require 'abstract_unit'
+
+uses_tzinfo 'TimeWithZoneTest' do
+  
+  class TimeWithZoneTest < Test::Unit::TestCase
+
+    def setup
+      @utc = Time.utc(2000, 1, 1, 0)
+      @time_zone = TimeZone['Eastern Time (US & Canada)']
+      @twz = ActiveSupport::TimeWithZone.new(@utc, @time_zone)
+    end
+  
+    def test_utc
+      assert_equal @utc, @twz.utc
+    end
+  
+    def test_time
+      assert_equal Time.utc(1999, 12, 31, 19), @twz.time
+    end
+  
+    def test_time_zone
+      assert_equal @time_zone, @twz.time_zone
+    end
+  
+    def test_in_time_zone
+      assert_equal ActiveSupport::TimeWithZone.new(@utc, TimeZone['Alaska']), @twz.in_time_zone('Alaska')
+    end
+  
+    def test_in_current_time_zone
+      with_time_zone 'Alaska' do
+        assert_equal ActiveSupport::TimeWithZone.new(@utc, TimeZone['Alaska']), @twz.in_current_time_zone
+      end
+    end
+  
+    def test_change_time_zone
+      silence_warnings do # silence warnings raised by tzinfo gem
+        assert_equal ActiveSupport::TimeWithZone.new(nil, TimeZone['Alaska'], Time.utc(1999, 12, 31, 19)), @twz.change_time_zone('Alaska')
+      end
+    end
+  
+    def test_change_time_zone_to_current
+      with_time_zone 'Alaska' do
+        assert_equal ActiveSupport::TimeWithZone.new(nil, TimeZone['Alaska'], Time.utc(1999, 12, 31, 19)), @twz.change_time_zone_to_current
+      end
+    end
+  
+    def test_utc?
+      assert_equal false, @twz.utc?
+      assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000)).utc?
+    end
+      
+    def test_formatted_offset
+      assert_equal '-05:00', @twz.formatted_offset
+      assert_equal '-04:00', ActiveSupport::TimeWithZone.new(Time.utc(2000, 6), @time_zone).formatted_offset #dst
+    end
+      
+    def test_dst?
+      assert_equal false, @twz.dst?
+      assert_equal true, ActiveSupport::TimeWithZone.new(Time.utc(2000, 6), @time_zone).dst?
+    end
+      
+    def test_zone
+      assert_equal 'EST', @twz.zone
+      assert_equal 'EDT', ActiveSupport::TimeWithZone.new(Time.utc(2000, 6), @time_zone).zone #dst
+    end
+      
+    def test_to_json
+      assert_equal "\"1999/12/31 19:00:00 -0500\"", @twz.to_json
+    end
+      
+    def test_strftime
+      assert_equal '1999-12-31 19:00:00 EST -0500', @twz.strftime('%Y-%m-%d %H:%M:%S %Z %z')
+    end
+      
+    def test_inspect
+      assert_equal 'Fri, 31 Dec 1999 19:00:00 EST -05:00', @twz.inspect
+    end
+      
+    def test_to_s
+      assert_equal '1999-12-31 19:00:00 -0500', @twz.to_s
+    end
+      
+    def test_to_s_db
+      assert_equal '2000-01-01 00:00:00', @twz.to_s(:db)
+    end
+      
+    def test_xmlschema
+      assert_equal "1999-12-31T19:00:00-05:00", @twz.xmlschema
+    end
+      
+    def test_compare
+      assert_equal  1, @twz <=> Time.utc(1999, 12, 31, 23, 59, 59)
+      assert_equal  0, @twz <=> Time.utc(2000)
+      assert_equal(-1, @twz <=> Time.utc(2000, 1, 1, 0, 0, 1))
+    end
+      
+    def test_plus
+      assert_equal Time.utc(1999, 12, 31, 19, 0 ,5), (@twz + 5).time
+    end
+      
+    def test_plus_with_duration
+      assert_equal Time.utc(2000, 1, 5, 19, 0 ,0), (@twz + 5.days).time
+    end
+      
+    def test_minus
+      assert_equal Time.utc(1999, 12, 31, 18, 59 ,55), (@twz - 5).time
+    end
+      
+    def test_minus_with_duration
+      assert_equal Time.utc(1999, 12, 26, 19, 0 ,0), (@twz - 5.days).time
+    end
+      
+    def test_to_time
+      assert_equal @twz, @twz.to_time
+    end
+      
+    def test_acts_like_time
+      assert @twz.acts_like?(:time)
+    end
+    
+    def test_is_a
+      assert @twz.is_a?(Time)
+      assert @twz.kind_of?(Time)
+      assert @twz.is_a?(ActiveSupport::TimeWithZone)
+    end
+      
+    def test_method_missing_with_time_return_value
+      assert_instance_of ActiveSupport::TimeWithZone, @twz.months_since(1)
+      assert_equal Time.utc(2000, 1, 31, 19, 0 ,0), @twz.months_since(1).time
+    end
+      
+    def test_method_missing_with_non_time_return_value
+      assert_equal 1999, @twz.year
+      assert_equal 12, @twz.month
+      assert_equal 31, @twz.day
+    end
+  
+    protected
+      def with_time_zone(zone)
+        old_zone, Time.zone = Time.zone, Time.get_zone(zone)
+        yield
+      ensure
+        Time.zone = old_zone
+      end
+  end
+  
+  class TimeWithZoneMethodsForTimeAndDateTimeTest < Test::Unit::TestCase
+    def setup
+      @t, @dt = Time.utc(2000), DateTime.civil(2000)
+    end
+
+    def test_in_time_zone
+      silence_warnings do # silence warnings raised by tzinfo gem
+        with_time_zone 'Eastern Time (US & Canada)' do
+          assert_equal 'Fri, 31 Dec 1999 15:00:00 AKST -09:00', @t.in_time_zone('Alaska').inspect
+          assert_equal 'Fri, 31 Dec 1999 15:00:00 AKST -09:00', @dt.in_time_zone('Alaska').inspect
+          assert_equal 'Fri, 31 Dec 1999 14:00:00 HST -10:00', @t.in_time_zone('Hawaii').inspect
+          assert_equal 'Fri, 31 Dec 1999 14:00:00 HST -10:00', @dt.in_time_zone('Hawaii').inspect
+        end
+      end
+    end
+
+    def test_in_current_time_zone
+      with_time_zone 'Alaska' do
+        assert_equal 'Fri, 31 Dec 1999 15:00:00 AKST -09:00', @t.in_current_time_zone.inspect
+        assert_equal 'Fri, 31 Dec 1999 15:00:00 AKST -09:00', @dt.in_current_time_zone.inspect
+      end
+      with_time_zone 'Hawaii' do
+        assert_equal 'Fri, 31 Dec 1999 14:00:00 HST -10:00', @t.in_current_time_zone.inspect
+        assert_equal 'Fri, 31 Dec 1999 14:00:00 HST -10:00', @dt.in_current_time_zone.inspect
+      end
+      with_time_zone nil do
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 UTC +00:00', @t.in_current_time_zone.inspect
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 UTC +00:00', @dt.in_current_time_zone.inspect
+      end
+    end
+    
+    def test_change_time_zone
+      silence_warnings do # silence warnings raised by tzinfo gem
+        with_time_zone 'Eastern Time (US & Canada)' do
+          assert_equal 'Sat, 01 Jan 2000 00:00:00 AKST -09:00', @t.change_time_zone('Alaska').inspect
+          assert_equal 'Sat, 01 Jan 2000 00:00:00 AKST -09:00', @dt.change_time_zone('Alaska').inspect
+          assert_equal 'Sat, 01 Jan 2000 00:00:00 HST -10:00', @t.change_time_zone('Hawaii').inspect
+          assert_equal 'Sat, 01 Jan 2000 00:00:00 HST -10:00', @dt.change_time_zone('Hawaii').inspect
+        end
+      end
+    end
+    
+    def test_change_time_zone_to_current
+      with_time_zone 'Alaska' do
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 AKST -09:00', @t.change_time_zone_to_current.inspect
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 AKST -09:00', @dt.change_time_zone_to_current.inspect
+      end
+      with_time_zone 'Hawaii' do
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 HST -10:00', @t.change_time_zone_to_current.inspect
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 HST -10:00', @dt.change_time_zone_to_current.inspect
+      end
+      with_time_zone nil do
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 UTC +00:00', @t.change_time_zone_to_current.inspect
+        assert_equal 'Sat, 01 Jan 2000 00:00:00 UTC +00:00', @dt.change_time_zone_to_current.inspect
+      end
+    end
+    
+    protected
+      def with_time_zone(zone)
+        old_zone, Time.zone = Time.zone, Time.get_zone(zone)
+        yield
+      ensure
+        Time.zone = old_zone
+      end
+  end
+end