license, tests, lib.

lib/timeout_interrupt.rb

@@ -0,0 +1,49 @@
+require 'ffi/libc'
+require 'timeout'
+
+module FFI
+	module LibC
+		attach_function :alarm, [:uint], :uint  unless FFI::LibC.respond_to? :alarm
+	end
+end
+
+module TimeoutInterrupt
+	def self.timeouts
+		@timeouts ||= {}
+	end
+
+	def self.alarm_trap sig
+		key, (at, bt) = TimeoutInterrupt.timeouts.min_by {|key,(at,bt)| at }
+		return  if Time.now < at
+		raise Timeout::Error, 'execution expired', bt
+	end
+
+	def self.setup_timeout
+		if TimeoutInterrupt.timeouts.empty?
+			Signal.trap( 'ALRM') {}
+			FFI::LibC.alarm 0
+		else
+			key, (at, bt) = TimeoutInterrupt.timeouts.min_by {|key,(at,bt)| at }
+			secs = (at - Time.now).to_i+1
+			TimeoutInterrupt.alarm_trap  if 1 > secs
+			Signal.trap 'ALRM', &TimeoutInterrupt.method( :alarm_trap)
+			FFI::LibC.alarm secs
+		end
+	end
+
+	def self.timeout seconds
+		seconds = seconds.to_i
+		raise Timeout::Error, "Timeout must be longer than '0' seconds."  unless 0 < seconds
+		return lambda {|&e| self.timeout seconds, &e }  unless block_given?
+		at = Time.now + seconds
+		key, bt = Random.rand( 2**64-1), Kernel.caller
+		begin
+			TimeoutInterrupt.timeouts[key] = [at, bt]
+			TimeoutInterrupt.setup_timeout
+			yield
+		ensure
+			TimeoutInterrupt.timeouts.delete key
+			TimeoutInterrupt.setup_timeout
+		end
+	end
+end