Adding TimeZone#parse

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9045 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Adding TimeZone#parse [Geoff Buesing]
+
 * Adding TimeZone#at and DateTime#to_f [Geoff Buesing]
 
 * TimeWithZone responds to Ruby 1.9 weekday-named query methods [Geoff Buesing]

activesupport/lib/active_support/time_with_zone.rb

@@ -10,12 +10,12 @@ module ActiveSupport
       @period = @utc ? period : get_period_and_ensure_valid_local_time
     end
   
-    # Returns a Time instance that represents the time in time_zone
+    # Returns a Time or DateTime instance that represents the time in time_zone
     def time
       @time ||= utc_to_local
     end
 
-    # Returns a Time instance that represents the time in UTC
+    # Returns a Time or DateTime instance that represents the time in UTC
     def utc
       @utc ||= local_to_utc
     end
@@ -222,11 +222,20 @@ module ActiveSupport
     
     private      
       def get_period_and_ensure_valid_local_time
-        @time_zone.period_for_local(@time)
-      rescue ::TZInfo::PeriodNotFound
-        # time is in the "spring forward" hour gap, so we're moving the time forward one hour and trying again
-        @time += 1.hour
-        retry
+        # we don't want a Time.local instance enforcing its own DST rules as well, 
+        # so transfer time values to a utc constructor if necessary
+        @time = transfer_time_values_to_utc_constructor(@time) unless @time.utc?
+        begin
+          @time_zone.period_for_local(@time)
+        rescue ::TZInfo::PeriodNotFound
+          # time is in the "spring forward" hour gap, so we're moving the time forward one hour and trying again
+          @time += 1.hour
+          retry
+        end
+      end
+      
+      def transfer_time_values_to_utc_constructor(time)
+        ::Time.utc_time(time.year, time.month, time.day, time.hour, time.min, time.sec, time.respond_to?(:usec) ? time.usec : 0)
       end
     
       # Replicating logic from TZInfo::Timezone#utc_to_local because we want to cache the period in an instance variable for reuse

activesupport/lib/active_support/values/time_zone.rb

@@ -197,6 +197,20 @@ class TimeZone
       utc.in_time_zone(self)
     end
     
+    # Method for creating new ActiveSupport::TimeWithZone instance in time zone of +self+ from parsed string. Example:
+    #
+    #   Time.zone = "Hawaii"                      # => "Hawaii"
+    #   Time.zone.parse('1999-12-31 14:00:00')    # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #
+    # If upper components are missing from the string, they are supplied from TimeZone#now:
+    #
+    #   Time.zone.now                 # => Fri, 31 Dec 1999 14:00:00 HST -10:00
+    #   Time.zone.parse('22:30:00')   # => Fri, 31 Dec 1999 22:30:00 HST -10:00
+    def parse(str, now=now)
+      time = Time.parse(str, now) rescue DateTime.parse(str)
+      ActiveSupport::TimeWithZone.new(nil, self, time)
+    end
+    
     # Returns an ActiveSupport::TimeWithZone instance representing the current time
     # in the time zone represented by +self+. Example:
     #
@@ -244,7 +258,7 @@ class TimeZone
     
   rescue LoadError # Tzinfo gem is not available
     # re-raise LoadError only when a tzinfo-dependent method is called:
-    %w(local at now today utc_to_local local_to_utc period_for_utc period_for_local tzinfo).each do |method|
+    %w(local at parse now today utc_to_local local_to_utc period_for_utc period_for_local tzinfo).each do |method|
       define_method(method) {|*args| raise LoadError, "TZInfo gem is required for TimeZone##{method}. `gem install tzinfo` and try again."}
     end
   end

activesupport/test/time_zone_test.rb

@@ -156,6 +156,14 @@ class TimeZoneTest < Test::Unit::TestCase
     assert_equal TimeZone["Hawaii"], time.time_zone
   end
   
+  def test_local_with_old_date
+    silence_warnings do # silence warnings raised by tzinfo gem
+      time = TimeZone["Hawaii"].local(1850, 2, 5, 15, 30, 45)
+      assert_equal [45,30,15,5,2,1850], time.to_a[0,6]
+      assert_equal TimeZone["Hawaii"], time.time_zone
+    end
+  end
+  
   def test_local_enforces_spring_dst_rules
     zone = TimeZone['Eastern Time (US & Canada)']
     twz = zone.local(2006,4,2,1,59,59) # 1 second before DST start
@@ -197,13 +205,39 @@ class TimeZoneTest < Test::Unit::TestCase
   end
   
   def test_at_with_old_date
-    zone = TimeZone['UTC']
-    secs = -3786825600.0
+    zone = TimeZone['Eastern Time (US & Canada)']
+    secs = DateTime.civil(1850).to_f
     twz = zone.at(secs)
-    assert_equal [0,0,0,1,1,1850], twz.to_a[0,6]
+    assert_equal [1850, 1, 1, 0], [twz.utc.year, twz.utc.mon, twz.utc.day, twz.utc.hour]
     assert_equal zone, twz.time_zone
     assert_equal secs, twz.to_f
   end
+  
+  def test_parse
+    zone = TimeZone['Eastern Time (US & Canada)']
+    twz = zone.parse('1999-12-31 19:00:00')
+    assert_equal Time.utc(1999,12,31,19), twz.time
+    assert_equal Time.utc(2000), twz.utc
+    assert_equal zone, twz.time_zone
+  end
+  
+  def test_parse_with_old_date
+    silence_warnings do # silence warnings raised by tzinfo gem
+      zone = TimeZone['Eastern Time (US & Canada)']
+      twz = zone.parse('1850-12-31 19:00:00')
+      assert_equal [0,0,19,31,12,1850], twz.to_a[0,6]
+      assert_equal zone, twz.time_zone
+    end
+  end
+  
+  uses_mocha 'TestParseWithIncompleteDate' do
+    def test_parse_with_incomplete_date
+      zone = TimeZone['Eastern Time (US & Canada)']
+      zone.stubs(:now).returns zone.local(1999,12,31)
+      twz = zone.parse('19:00:00')
+      assert_equal Time.utc(1999,12,31,19), twz.time
+    end
+  end
 
   protected
     def with_env_tz(new_tz = 'US/Eastern')