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Diffstat (limited to 'lib/monitor.rb')
| -rw-r--r-- | lib/monitor.rb | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/lib/monitor.rb b/lib/monitor.rb new file mode 100644 index 0000000000..75d9c35821 --- /dev/null +++ b/lib/monitor.rb @@ -0,0 +1,229 @@ +=begin + +monitor.rb +Author: Shugo Maeda <shugo@netlab.co.jp> +Version: 1.2.1 + +USAGE: + + foo = Foo.new + foo.extend(MonitorMixin) + cond = foo.new_cond + + thread1: + foo.synchronize { + ... + cond.wait_until { foo.done? } + ... + } + + thread2: + foo.synchronize { + foo.do_something + cond.signal + } + +=end + +module MonitorMixin + module Accessible + protected + attr_accessor :mon_owner, :mon_count + attr_reader :mon_entering_queue, :mon_waiting_queue + end + + module Initializable + protected + def mon_initialize + @mon_owner = nil + @mon_count = 0 + @mon_entering_queue = [] + @mon_waiting_queue = [] + end + end + + class ConditionVariable + class Timeout < Exception; end + + include Accessible + + def wait(timeout = nil) + if @monitor.mon_owner != Thread.current + raise ThreadError, "current thread not owner" + end + + Thread.critical = true + count = @monitor.mon_count + @monitor.mon_count = 0 + @monitor.mon_owner = nil + if @monitor.mon_waiting_queue.empty? + t = @monitor.mon_entering_queue.shift + else + t = @monitor.mon_waiting_queue.shift + end + t.wakeup if t + @waiters.push(Thread.current) + + if timeout + t = Thread.current + timeout_thread = Thread.start { + sleep(timeout) + t.raise(Timeout.new) + } + end + begin + Thread.stop + rescue Timeout + @waiters.delete(Thread.current) + ensure + if timeout && timeout_thread.alive? + Thread.kill(timeout_thread) + end + end + + Thread.critical = true + while @monitor.mon_owner && + @monitor.mon_owner != Thread.current + @monitor.mon_waiting_queue.push(Thread.current) + Thread.stop + Thread.critical = true + end + @monitor.mon_owner = Thread.current + @monitor.mon_count = count + Thread.critical = false + end + + def wait_while + while yield + wait + end + end + + def wait_until + until yield + wait + end + end + + def signal + if @monitor.mon_owner != Thread.current + raise ThreadError, "current thread not owner" + end + Thread.critical = true + t = @waiters.shift + t.wakeup if t + Thread.critical = false + Thread.pass + end + + def broadcast + if @monitor.mon_owner != Thread.current + raise ThreadError, "current thread not owner" + end + Thread.critical = true + for t in @waiters + t.wakeup + end + @waiters.clear + Thread.critical = false + Thread.pass + end + + def count_waiters + return @waiters.length + end + + private + def initialize(monitor) + @monitor = monitor + @waiters = [] + end + end + + include Accessible + include Initializable + extend Initializable + + def self.extend_object(obj) + super(obj) + obj.mon_initialize + end + + def try_mon_enter + result = false + Thread.critical = true + if mon_owner.nil? + self.mon_owner = Thread.current + end + if mon_owner == Thread.current + self.mon_count += 1 + result = true + end + Thread.critical = false + return result + end + + def mon_enter + Thread.critical = true + while mon_owner != nil && mon_owner != Thread.current + mon_entering_queue.push(Thread.current) + Thread.stop + Thread.critical = true + end + self.mon_owner = Thread.current + self.mon_count += 1 + Thread.critical = false + end + + def mon_exit + if mon_owner != Thread.current + raise ThreadError, "current thread not owner" + end + Thread.critical = true + self.mon_count -= 1 + if mon_count == 0 + self.mon_owner = nil + if mon_waiting_queue.empty? + t = mon_entering_queue.shift + else + t = mon_waiting_queue.shift + end + end + t.wakeup if t + Thread.critical = false + Thread.pass + end + + def mon_synchronize + mon_enter + begin + yield + ensure + mon_exit + end + end + alias synchronize mon_synchronize + + def new_cond + return ConditionVariable.new(self) + end + +private + def initialize(*args) + super + mon_initialize + end +end + +class Monitor + include MonitorMixin + alias try_enter try_mon_enter + alias enter mon_enter + alias exit mon_exit + alias owner mon_owner +end + +# Local variables: +# mode: Ruby +# tab-width: 8 +# End: |