Preallocate signal trap events.

Assisted-By: devx/3236e566-7538-432e-a30a-2bdf37265ed4

Author: samuel-williams-shopify

lib/async/container/signals.rb

@@ -32,7 +32,7 @@ def call
 			# @parameter events [Events] The queue used to receive signal events.
 			def initialize(events = Events.new)
 				@events = events
-				@handlers = {}
+				@traps = {}
 			end
 
 			# @attribute [Events] The queue used to receive signal events.
@@ -42,7 +42,11 @@ def initialize(events = Events.new)
 			# If no block is provided, the signal will be ignored while trapped.
 			# @parameter signal [Symbol | String | Integer] The signal to trap.
 			def trap(signal, &block)
-				@handlers[signal] = block
+				if block
+					@traps[signal] = Event.new(signal, block).freeze
+				else
+					@traps[signal] = nil
+				end
 			end
 
 			# Ignore a signal while trapped.
@@ -62,8 +66,8 @@ def wait
 			def trapped
 				previous = {}
 
-				@handlers.each do |signal, handler|
-					previous[signal] = install(signal, handler)
+				@traps.each do |signal, event|
+					previous[signal] = install(signal, event)
 				end
 
 				yield self
@@ -75,10 +79,10 @@ def trapped
 
 			private
 
-			def install(signal, handler)
-				if handler
+			def install(signal, event)
+				if event
 					::Signal.trap(signal) do
-						@events << Event.new(signal, handler)
+						@events << event
 					end
 				else
 					::Signal.trap(signal, "IGNORE")

test/async/container/signals.rb

@@ -79,6 +79,20 @@
 			expect(applied).to be == true
 		end
 
+		it "reuses a frozen event for trapped signals" do
+			signals.trap(:USR1){}
+			
+			signals.trapped do
+				::Process.kill(:USR1, ::Process.pid)
+				event = signals.wait
+				
+				expect(event.frozen?).to be == true
+				
+				::Process.kill(:USR1, ::Process.pid)
+				expect(signals.wait).to be == event
+			end
+		end
+		
 		it "ignores signals without a handler" do
 			signals.trap(:USR1)