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 92
def broadcast
# TODO: imcomplete
waiters0 = nil
@waiters_mutex.synchronize do
waiters0 = @waiters.dup
@waiters.clear
end
for t in waiters0
begin
t.run
rescue ThreadError
end
end
self
end
Wakes up the first thread in line waiting for this lock.
# File thread.rb, line 79
def signal
begin
t = @waiters_mutex.synchronize { @waiters.shift }
t.run if t
rescue ThreadError
retry
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)
begin
# TODO: mutex should not be used
@waiters_mutex.synchronize do
@waiters.push(Thread.current)
end
mutex.sleep timeout
end
self
end