Replaced Channel::Buffer::NO_VALUE with Concurrent::NULL

Author: jdantonio

lib/concurrent/channel.rb

@@ -117,20 +117,20 @@ def offer?(item)
 
     def take
       item = do_take
-      item == Buffer::NO_VALUE ? nil : item
+      item == Concurrent::NULL ? nil : item
     end
     alias_method :receive, :take
     alias_method :~, :take
 
     def take!
       item = do_take
-      raise Error if item == Buffer::NO_VALUE
+      raise Error if item == Concurrent::NULL
       item
     end
 
     def take?
       item = do_take
-      item = if item == Buffer::NO_VALUE
+      item = if item == Concurrent::NULL
                Concurrent::Maybe.nothing
              else
                Concurrent::Maybe.just(item)
@@ -155,13 +155,13 @@ def take?
     #   end
     def next
       item, more = do_next
-      item = nil if item == Buffer::NO_VALUE
+      item = nil if item == Concurrent::NULL
       return item, more
     end
 
     def next?
       item, more = do_next
-      item = if item == Buffer::NO_VALUE
+      item = if item == Concurrent::NULL
                Concurrent::Maybe.nothing
              else
                Concurrent::Maybe.just(item)
@@ -170,17 +170,17 @@ def next?
     end
 
     def poll
-      (item = do_poll) == Buffer::NO_VALUE ? nil : item
+      (item = do_poll) == Concurrent::NULL ? nil : item
     end
 
     def poll!
       item = do_poll
-      raise Error if item == Buffer::NO_VALUE
+      raise Error if item == Concurrent::NULL
       item
     end
 
     def poll?
-      if (item = do_poll) == Buffer::NO_VALUE
+      if (item = do_poll) == Concurrent::NULL
         Concurrent::Maybe.nothing
       else
         Concurrent::Maybe.just(item)
@@ -191,7 +191,7 @@ def each
       raise ArgumentError.new('no block given') unless block_given?
       loop do
         item, more = do_next
-        if item != Buffer::NO_VALUE
+        if item != Concurrent::NULL
           yield(item)
         elsif !more
           break

lib/concurrent/channel/buffer/base.rb

@@ -4,9 +4,6 @@ module Concurrent
   class Channel
     module Buffer
 
-      # Placeholder for when a buffer slot contains no value.
-      NO_VALUE = Object.new
-
       # Abstract base class for all Channel buffers.
       #
       # {Concurrent::Channel} objects maintain an internal, queue-like
@@ -118,7 +115,7 @@ def offer(item)
         #   are available the remaining items can still be taken. Once the
         #   buffer closes, no remaining items can be taken.
         #
-        #   @return [Object] the item removed from the buffer; `NO_VALUE` once
+        #   @return [Object] the item removed from the buffer; `Concurrent::NULL` once
         #     the buffer has closed.
         #
         # @raise [NotImplementedError] until overridden in a subclass.
@@ -137,7 +134,7 @@ def take
         #   values, "more" (a boolean), will always be `true` when the buffer is
         #   open. The "more" value will be `false` when the channel has been
         #   closed and all values have already been received. When "more" is
-        #   false the returned item will be `NO_VALUE`.
+        #   false the returned item will be `Concurrent::NULL`.
         #
         #   Note that when multiple threads access the same channel a race
         #   condition can occur when using this method. A call to `next` from
@@ -161,7 +158,7 @@ def next
         #   immediately. Failing to return a value does not necessarily
         #   indicate that the buffer is closed, just that it is empty.
         #
-        #   @return [Object] the next item from the buffer or `NO_VALUE` if
+        #   @return [Object] the next item from the buffer or `Concurrent::NULL` if
         #     the buffer is empty.
         #
         # @raise [NotImplementedError] until overridden in a subclass.

lib/concurrent/channel/buffer/buffered.rb

@@ -1,3 +1,4 @@
+require 'concurrent/constants'
 require 'concurrent/channel/buffer/base'
 
 module Concurrent
@@ -56,7 +57,7 @@ def next
           loop do
             synchronize do
               if ns_closed? && ns_empty?
-                return NO_VALUE, false
+                return Concurrent::NULL, false
               elsif !ns_empty?
                 item = buffer.shift
                 return item, true
@@ -70,7 +71,7 @@ def next
         def poll
           synchronize do
             if ns_empty?
-              NO_VALUE
+              Concurrent::NULL
             else
               buffer.shift
             end

lib/concurrent/channel/buffer/ticker.rb

@@ -1,3 +1,4 @@
+require 'concurrent/constants'
 require 'concurrent/utility/monotonic_time'
 require 'concurrent/channel/tick'
 require 'concurrent/channel/buffer/base'
@@ -20,7 +21,7 @@ def take
           # a Go timer will block forever if stopped
           loop do
             tick = do_poll
-            return tick if tick != NO_VALUE
+            return tick if tick != Concurrent::NULL
             Thread.pass
           end
         end
@@ -30,7 +31,7 @@ def next
           # it will always return `true` for more
           loop do
             tick = do_poll
-            return tick, true if tick != NO_VALUE
+            return tick, true if tick != Concurrent::NULL
             Thread.pass
           end
         end
@@ -66,7 +67,7 @@ def do_poll
               @next_tick = now + @interval
               return tick
             else
-              return NO_VALUE
+              return Concurrent::NULL
             end
           end
         end

lib/concurrent/channel/buffer/timer.rb

@@ -1,3 +1,4 @@
+require 'concurrent/constants'
 require 'concurrent/utility/monotonic_time'
 require 'concurrent/channel/tick'
 require 'concurrent/channel/buffer/base'
@@ -20,7 +21,7 @@ def take
           # a Go timer will block forever if stopped
           loop do
             tick = do_poll
-            return tick if tick != NO_VALUE
+            return tick if tick != Concurrent::NULL
             Thread.pass
           end
         end
@@ -30,7 +31,7 @@ def next
           # it will always return `true` for more
           loop do
             tick = do_poll
-            return tick, true if tick != NO_VALUE
+            return tick, true if tick != Concurrent::NULL
             Thread.pass
           end
         end
@@ -65,7 +66,7 @@ def do_poll
               self.closed = true
               return Concurrent::Channel::Tick.new(@tick)
             else
-              return NO_VALUE
+              return Concurrent::NULL
             end
           end
         end

lib/concurrent/channel/buffer/unbuffered.rb

@@ -1,3 +1,4 @@
+require 'concurrent/constants'
 require 'concurrent/channel/buffer/base'
 require 'concurrent/atomic/atomic_reference'
 
@@ -87,7 +88,7 @@ def offer(item)
         # and this method will return.
         def take
           mine = synchronize do
-            return NO_VALUE if ns_closed? && putting.empty?
+            return Concurrent::NULL if ns_closed? && putting.empty?
 
             ref = Concurrent::AtomicReference.new(nil)
             if putting.empty?
@@ -112,10 +113,10 @@ def take
         # waiting to {#put} items onto the buffer. When there is a thread
         # waiting to put an item this method will take the item and return
         # it immediately. When there are no threads waiting to put or the
-        # buffer is closed, this method will return `NO_VALUE` immediately.
+        # buffer is closed, this method will return `Concurrent::NULL` immediately.
         def poll
           synchronize do
-            return NO_VALUE if putting.empty?
+            return Concurrent::NULL if putting.empty?
 
             put = putting.shift
             value = put.value
@@ -133,7 +134,7 @@ def poll
         # @see {#take}
         def next
           item = take
-          more = (item != NO_VALUE)
+          more = (item != Concurrent::NULL)
           return item, more
         end
 

spec/concurrent/channel/buffer/base_shared.rb

@@ -65,17 +65,17 @@
   end
 
   context '#take' do
-    it 'returns NO_VALUE when closed' do
+    it 'returns Concurrent::NULL when closed' do
       subject.close
-      expect(subject.take).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(subject.take).to eq Concurrent::NULL
     end
   end
 
   context '#next' do
-    it 'returns NO_VALUE, false when closed' do
+    it 'returns Concurrent::NULL, false when closed' do
       subject.close
       item, more = subject.next
-      expect(item).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(item).to eq Concurrent::NULL
       expect(more).to be false
     end
   end
@@ -92,13 +92,13 @@
       expect(subject.poll).to eq 42
     end
 
-    it 'returns NO_VALUE immediately if no item is available' do
-      expect(subject.poll).to eq Concurrent::Channel::Buffer::NO_VALUE
+    it 'returns Concurrent::NULL immediately if no item is available' do
+      expect(subject.poll).to eq Concurrent::NULL
     end
 
-    it 'returns NO_VALUE when closed' do
+    it 'returns Concurrent::NULL when closed' do
       subject.close
-      expect(subject.poll).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(subject.poll).to eq Concurrent::NULL
     end
   end
 

spec/concurrent/channel/buffer/buffered_shared.rb

@@ -90,9 +90,9 @@
       expect(t.status).to be false
     end
 
-    it 'returns NO_VALUE when closed and empty' do
+    it 'returns Concurrent::NULL when closed and empty' do
       subject.close
-      expect(subject.take).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(subject.take).to eq Concurrent::NULL
     end
   end
 
@@ -158,7 +158,7 @@
       end
     end
 
-    it 'returns NO_VALUE, false when closed and no items remain' do
+    it 'returns Concurrent::NULL, false when closed and no items remain' do
       capacity = subject.capacity
       expect(capacity).to be >= 1
 
@@ -168,7 +168,7 @@
       capacity.times { subject.next }
 
       item, more = subject.next
-      expect(item).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(item).to eq Concurrent::NULL
       expect(more).to be false
     end
   end

spec/concurrent/channel/buffer/timer_spec.rb

@@ -19,7 +19,7 @@ module Concurrent::Channel::Buffer
     context '#poll' do
       it 'closes automatically on first take' do
         loop do
-          break if subject.poll != NO_VALUE
+          break if subject.poll != Concurrent::NULL
         end
         expect(subject).to be_closed
       end
@@ -29,7 +29,7 @@ module Concurrent::Channel::Buffer
       it 'closes automatically on first take' do
         loop do
           value, _ = subject.next
-          break if value != NO_VALUE
+          break if value != Concurrent::NULL
         end
         expect(subject).to be_closed
       end

spec/concurrent/channel/buffer/timing_buffer_shared.rb

@@ -83,9 +83,9 @@
 
   context '#poll' do
 
-    it 'returns NO_VALUE when the timer is not ready' do
+    it 'returns Concurrent::NULL when the timer is not ready' do
       subject = described_class.new(0.1)
-      expect(subject.poll).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(subject.poll).to eq Concurrent::NULL
     end
 
     it 'returns a Tick' do
@@ -94,9 +94,9 @@
       expect(subject.poll).to be_a Concurrent::Channel::Tick
     end
 
-    it 'returns NO_VALUE when closed' do
+    it 'returns Concurrent::NULL when closed' do
       subject.close
-      expect(subject.poll).to eq Concurrent::Channel::Buffer::NO_VALUE
+      expect(subject.poll).to eq Concurrent::NULL
     end
 
     it 'triggers after the specified time interval' do