Add EM::Channel#pop to receive one message from a channel

thatothermitch · May 12, 2009 · 391b730 · 391b730
1 parent eb70e07
commit 391b730
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diff --git a/lib/em/channel.rb b/lib/em/channel.rb
@@ -39,6 +39,16 @@ def push(*items)
     end
     alias << push
 
+    # Receive exactly one message from the channel.
+    def pop(*a, &b)
+      EM.schedule {
+        name = subscribe do |*args|
+          unsubscribe(name)
+          EM::Callback(*a, &b).call(*args)
+        end
+      }
+    end
+
     private
     def gen_id # :nodoc:
       @uid += 1

diff --git a/tests/test_channel.rb b/tests/test_channel.rb
@@ -25,6 +25,18 @@ def test_channel_unsubscribe
     assert_not_equal 1, s
   end
 
+  def test_channel_pop
+    s = 0
+    EM.run do
+      c = EM::Channel.new
+      c.pop{ |v| s = v }
+      c << 1
+      c << 2
+      EM.next_tick { EM.stop }
+    end
+    assert_equal 1, s
+  end
+
   def test_channel_reactor_thread_push
     out = []
     c = EM::Channel.new