Object
ConditionVariable objects augment class Mutex. Using condition variables, it is possible to suspend while in the middle of a critical section until a resource becomes available.
Example:
require 'thread' mutex = Mutex.new resource = ConditionVariable.new a = Thread.new { mutex.synchronize { # Thread 'a' now needs the resource resource.wait(mutex) # 'a' can now have the resource } } b = Thread.new { mutex.synchronize { # Thread 'b' has finished using the resource resource.signal } }
Creates a new ConditionVariable
# File thread.rb, line 54 def initialize @waiters = {} @waiters_mutex = Mutex.new end
Wakes up all threads waiting for this lock.
# File thread.rb, line 101 def broadcast Thread.handle_interrupt(StandardError => :on_blocking) do threads = nil @waiters_mutex.synchronize do threads = @waiters.keys @waiters.clear end for t in threads begin t.run rescue ThreadError end end end self end
Wakes up the first thread in line waiting for this lock.
# File thread.rb, line 86 def signal Thread.handle_interrupt(StandardError => :on_blocking) do begin t, _ = @waiters_mutex.synchronize { @waiters.shift } t.run if t rescue ThreadError retry # t was already dead? end end self end
Releases the lock held in mutex
and waits; reacquires the lock
on wakeup.
If timeout
is given, this method returns after
timeout
seconds passed, even if no other thread doesn’t
signal.
# File thread.rb, line 65 def wait(mutex, timeout=nil) Thread.handle_interrupt(StandardError => :never) do begin Thread.handle_interrupt(StandardError => :on_blocking) do @waiters_mutex.synchronize do @waiters[Thread.current] = true end mutex.sleep timeout end ensure @waiters_mutex.synchronize do @waiters.delete(Thread.current) end end end self end
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