@@ -1,16 +1,16 @@ class Semaphore def initialize(resource_count = 0) - @available_resource_count = resource_count + @available_resource_count = resource_count.to_i @mutex = Mutex.new @waiting_threads = [] end def wait - make_thread_wait unless resource_is_available + sleep_thread unless available_resource? end def signal - schedule_waiting_thread if thread_is_waiting + schedule_waiting_thread if waiting_thread? end def synchronize @@ -22,18 +22,18 @@ class Semaphore private - def resource_is_available + def available_resource? @mutex.synchronize do return (@available_resource_count -= 1) >= 0 end end - def make_thread_wait + def sleep_thread @waiting_threads << Thread.current Thread.stop end - def thread_is_waiting + def waiting_thread? @mutex.synchronize do return (@available_resource_count += 1) <= 0 end lib/mongrel/semaphore.rb @@ -110,6 +110,18 @@ class TestSemaphore < Test::Unit::TestCase assert_equal 3, run_count end + def test_semaphore_with_several_available_resources_schedules_several_threads + @semaphore = Semaphore.new(4) + active = [false, false, false, false] + 4.times do |i| + thread = Thread.new { @semaphore.synchronize { active[i] = true } } + end + give_up_my_time_slice + @semaphore.wait + + assert active.all? + end + private def give_up_my_time_slice test/unit/test_semaphore.rb 5915b8af83b1d191ecabde76da56932cc08c107a Pivotal Labs pivotal@cumberland.flood.pivotallabs.com http://github.com/pivotal/mongrel/commit/c48230d78ccb099eb901e6241227363d3b21c27d c48230d78ccb099eb901e6241227363d3b21c27d 2008-08-27T18:39:11-07:00 2008-08-27T18:39:11-07:00 ssuring resource_count is an int f0413bdd88a33e0239a01e84f3ea616b46952405 Pivotal Labs pivotal@cumberland.flood.pivotallabs.com