Skip double occurrences over DST

Fixed #189

lib/ice_cube/schedule.rb

@@ -397,25 +397,27 @@ def reset
 
     # Find all of the occurrences for the schedule between opening_time
     # and closing_time
+    # Iteration is unrolled in pairs to skip duplicate times in end of DST
     def enumerate_occurrences(opening_time, closing_time = nil, &block)
       opening_time = TimeUtil.match_zone(opening_time, start_time)
       closing_time = TimeUtil.match_zone(closing_time, start_time)
       opening_time += start_time.subsec - opening_time.subsec rescue 0
       reset
       opening_time = start_time if opening_time < start_time
-      # walk up to the opening time - and off we go
-      # If we have rules with counts, we need to walk from the beginning of time,
-      # otherwise opening_time
-      time = full_required? ? start_time : opening_time
+      t1 = full_required? ? start_time : opening_time
       e = Enumerator.new do |yielder|
         loop do
-          res = next_time(time, closing_time)
-          break unless res
-          break if closing_time && res > closing_time
-          if res >= opening_time
-            yielder.yield (block_given? ? block.call(res) : res)
+          break unless (t0 = next_time(t1, closing_time))
+          break if closing_time && t0 > closing_time
+          yielder << (block_given? ? block.call(t0) : t0) if t0 >= opening_time
+          break unless (t1 = next_time(t0 + 1, closing_time))
+          break if closing_time && t1 > closing_time
+          if TimeUtil.same_clock?(t0, t1) && recurrence_rules.any?(&:dst_adjust?)
+            wind_back_dst
+            next t1 += 1
           end
-          time = res + 1
+          yielder << (block_given? ? block.call(t1) : t1) if t1 >= opening_time
+          t1 += 1
         end
       end
     end
@@ -437,7 +439,8 @@ def next_time(time, closing_time)
       end
     end
 
-    # Return a boolean indicating if any rule needs to be run from the start of time
+    # Indicate if any rule needs to be run from the start of time
+    # If we have rules with counts, we need to walk from the beginning of time
     def full_required?
       @all_recurrence_rules.any?(&:full_required?) ||
       @all_exception_rules.any?(&:full_required?)
@@ -481,6 +484,12 @@ def recurrence_rules_with_implicit_start_occurrence
       end
     end
 
+    def wind_back_dst
+      recurrence_rules.each do |rule|
+        rule.skipped_for_dst
+      end
+    end
+
   end
 
 end

lib/ice_cube/time_util.rb

@@ -16,6 +16,8 @@ module TimeUtil
       :november => 11, :december => 12
     }
 
+    CLOCK_VALUES = [:year, :month, :day, :hour, :min, :sec]
+
     # Provides a Time.now without the usec, in the reference zone or utc offset
     def self.now(reference=Time.now)
       match_zone(Time.at(Time.now.to_i), reference)
@@ -210,6 +212,10 @@ def self.dst_change(time)
       end
     end
 
+    def self.same_clock?(t1, t2)
+      CLOCK_VALUES.all? { |i| t1.send(i) == t2.send(i) }
+    end
+
     # A utility class for safely moving time around
     class TimeWrapper
 

lib/ice_cube/validated_rule.rb

@@ -46,6 +46,14 @@ def next_time(time, schedule, closing_time)
       @time
     end
 
+    def skipped_for_dst
+      @uses -= 1 if @uses > 0
+    end
+
+    def dst_adjust?
+      @validations[:interval].any? &:dst_adjust?
+    end
+
     def to_s
       builder = StringBuilder.new
       @validations.each do |name, validations|
@@ -132,12 +140,11 @@ def validated_results(validations_for_type)
     end
 
     def shift_time_by_validation(res, vals)
-      return unless res.min
-      type = vals.first.type # get the jump type
-      dst_adjust = !vals.first.respond_to?(:dst_adjust?) || vals.first.dst_adjust?
-      wrapper = TimeUtil::TimeWrapper.new(@time, dst_adjust)
-      wrapper.add(type, res.min)
-      wrapper.clear_below(type)
+      return unless (interval = res.min)
+      validation = vals.first
+      wrapper = TimeUtil::TimeWrapper.new(@time, validation.dst_adjust?)
+      wrapper.add(validation.type, interval)
+      wrapper.clear_below(validation.type)
 
       # Move over DST if blocked, no adjustments
       if wrapper.to_time <= @time

lib/ice_cube/validations/count.rb

@@ -29,6 +29,10 @@ def type
         :limit
       end
 
+      def dst_adjust?
+        false
+      end
+
       def validate(time, schedule)
         raise CountExceeded if rule.uses && rule.uses >= count
       end

lib/ice_cube/validations/daily_interval.rb

@@ -22,6 +22,10 @@ def type
         :day
       end
 
+      def dst_adjust?
+        true
+      end
+
       def validate(step_time, schedule)
         t0, t1 = schedule.start_time, step_time
         days = Date.new(t1.year, t1.month, t1.day) -

lib/ice_cube/validations/day.rb

@@ -31,6 +31,10 @@ def type
         :wday
       end
 
+      def dst_adjust?
+        true
+      end
+
       def build_s(builder)
         builder.piece(:day) << day
       end

lib/ice_cube/validations/day_of_month.rb

@@ -28,6 +28,10 @@ def type
         :day
       end
 
+      def dst_adjust?
+        true
+      end
+
       def build_s(builder)
         builder.piece(:day_of_month) << StringBuilder.nice_number(day)
       end

lib/ice_cube/validations/day_of_week.rb

@@ -26,6 +26,10 @@ def type
         :day
       end
 
+      def dst_adjust?
+        true
+      end
+
       def validate(step_time, schedule)
         wday = step_time.wday
         offset = (day < wday) ? (7 - wday + day) : (day - wday)

lib/ice_cube/validations/day_of_year.rb

@@ -25,6 +25,10 @@ def type
         :day
       end
 
+      def dst_adjust?
+        true
+      end
+
       def validate(step_time, schedule)
         days_in_year = TimeUtil.days_in_year(step_time)
         yday = day < 0 ? day + days_in_year : day

lib/ice_cube/validations/hour_of_day.rb

@@ -29,6 +29,10 @@ def type
         :hour
       end
 
+      def dst_adjust?
+        true
+      end
+
       def build_s(builder)
         builder.piece(:hour_of_day) << StringBuilder.nice_number(hour)
       end

lib/ice_cube/validations/minute_of_hour.rb

@@ -28,6 +28,10 @@ def type
         :min
       end
 
+      def dst_adjust?
+        false
+      end
+
       def build_s(builder)
         builder.piece(:minute_of_hour) << StringBuilder.nice_number(minute)
       end

lib/ice_cube/validations/month_of_year.rb

@@ -29,6 +29,10 @@ def type
         :month
       end
 
+      def dst_adjust?
+        true
+      end
+
       def build_s(builder)
         builder.piece(:month_of_year) << Date::MONTHNAMES[month]
       end

lib/ice_cube/validations/monthly_interval.rb

@@ -21,6 +21,10 @@ def type
         :month
       end
 
+      def dst_adjust?
+        true
+      end
+
       def validate(step_time, schedule)
         t0, t1 = schedule.start_time, step_time
         months = (t1.month - t0.month) +

lib/ice_cube/validations/second_of_minute.rb

@@ -28,6 +28,10 @@ def type
         :sec
       end
 
+      def dst_adjust?
+        false
+      end
+
       def build_s(builder)
         builder.piece(:second_of_minute) << StringBuilder.nice_number(second)
       end

lib/ice_cube/validations/until.rb

@@ -29,6 +29,10 @@ def type
         :limit
       end
 
+      def dst_adjust?
+        false
+      end
+
       def validate(step_time, schedule)
         raise UntilExceeded if step_time > time
       end

lib/ice_cube/validations/weekly_interval.rb

@@ -29,6 +29,10 @@ def type
         :day
       end
 
+      def dst_adjust?
+        true
+      end
+
       def validate(step_time, schedule)
         t0, t1 = schedule.start_time, step_time
         d0 = Date.new(t0.year, t0.month, t0.day)

lib/ice_cube/validations/yearly_interval.rb

@@ -20,6 +20,10 @@ def type
         :year
       end
 
+      def dst_adjust?
+        true
+      end
+
       def validate(step_time, schedule)
         years = step_time.year - schedule.start_time.year
         offset = (years % interval).nonzero?

spec/examples/dst_spec.rb

@@ -263,4 +263,36 @@
     schedule.first(3).should == [Time.local(2010, 4, 10, 12, 0, 0), Time.local(2011, 4, 10, 12, 0, 0), Time.local(2012, 4, 10, 12, 0, 0)]
   end
 
+  it "skips double occurrences from end of DST" do
+    Time.zone = "America/Denver"
+    t0 = Time.zone.parse("Sun, 03 Nov 2013 01:30:00 MDT -06:00")
+    schedule = IceCube::Schedule.new(t0) { |s| s.rrule IceCube::Rule.daily.count(3) }
+    schedule.all_occurrences.should == [t0, t0 + 25*ONE_HOUR, t0 + 49*ONE_HOUR]
+  end
+
+  it "does not skip hourly rules over DST" do
+    Time.zone = "America/Denver"
+    t0 = Time.zone.parse("Sun, 03 Nov 2013 01:30:00 MDT -06:00")
+    schedule = IceCube::Schedule.new(t0) { |s| s.rrule IceCube::Rule.hourly.count(3) }
+    schedule.all_occurrences.should == [t0, t0 + ONE_HOUR, t0 + 2*ONE_HOUR]
+  end
+
+  it "does not skip minutely rules with minute of hour over DST" do
+    Time.zone = "America/Denver"
+    t0 = Time.zone.parse("Sun, 03 Nov 2013 01:30:00 MDT -06:00")
+    schedule = IceCube::Schedule.new(t0) { |s| s.rrule IceCube::Rule.hourly.count(3) }
+    schedule.rrule IceCube::Rule.minutely.minute_of_hour([0, 15, 30, 45])
+    schedule.first(5).should == [t0, t0 + 15*60, t0 + 30*60, t0 + 45*60, t0 + 60*60]
+  end
+
+  it "does not skip minutely rules with second of minute over DST" do
+    Time.zone = "America/Denver"
+    t0 = Time.zone.parse("Sun, 03 Nov 2013 01:30:00 MDT -06:00")
+    schedule = IceCube::Schedule.new(t0) { |s| s.rrule IceCube::Rule.hourly.count(3) }
+    schedule.rrule IceCube::Rule.minutely(15).second_of_minute(0)
+    schedule.first(5).should == [t0, t0 + 15*60, t0 + 30*60, t0 + 45*60, t0 + 60*60]
+  end
+
+
+
 end