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|
#
# thwait.rb - thread synchronization class
# $Release Version: 0.9 $
# $Revision: 1.3 $
# by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd.)
require "thread.rb"
require "e2mmap.rb"
#
# This class watches for termination of multiple threads. Basic functionality
# (wait until specified threads have terminated) can be accessed through the
# class method ThreadsWait::all_waits. Finer control can be gained using
# instance methods.
#
# Example:
#
# ThreadsWait.all_waits(thr1, thr2, ...) do |t|
# STDERR.puts "Thread #{t} has terminated."
# end
#
#
# th = ThreadsWait.new(thread1,...)
# th.next_wait # next one to be done
#
#
class ThreadsWait
extend Exception2MessageMapper
def_exception("ErrNoWaitingThread", "No threads for waiting.")
def_exception("ErrNoFinishedThread", "No finished threads.")
#
# Waits until all specified threads have terminated. If a block is provided,
# it is executed for each thread as they terminate.
#
def ThreadsWait.all_waits(*threads) # :yield: thread
tw = ThreadsWait.new(*threads)
if block_given?
tw.all_waits do |th|
yield th
end
else
tw.all_waits
end
end
#
# Creates a ThreadsWait object, specifying the threads to wait on.
# Non-blocking.
#
def initialize(*threads)
@threads = []
@wait_queue = Queue.new
join_nowait(*threads) unless threads.empty?
end
# Returns the array of threads that have not terminated yet.
attr :threads
#
# Returns +true+ if there are no threads in the pool still running.
#
def empty?
@threads.empty?
end
#
# Returns +true+ if any thread has terminated and is ready to be collected.
#
def finished?
!@wait_queue.empty?
end
#
# Waits for specified threads to terminate, and returns when one of
# the threads terminated.
#
def join(*threads)
join_nowait(*threads)
next_wait
end
#
# Specifies the threads that this object will wait for, but does not actually
# wait.
#
def join_nowait(*threads)
threads.flatten!
@threads.concat threads
for th in threads
Thread.start(th) do |t|
begin
t.join
ensure
@wait_queue.push t
end
end
end
end
#
# Waits until any of the specified threads has terminated, and returns the one
# that does.
#
# If there is no thread to wait, raises +ErrNoWaitingThread+. If +nonblock+
# is true, and there is no terminated thread, raises +ErrNoFinishedThread+.
#
def next_wait(nonblock = nil)
ThreadsWait.fail ErrNoWaitingThread if @threads.empty?
begin
@threads.delete(th = @wait_queue.pop(nonblock))
th
rescue ThreadError
ThreadsWait.fail ErrNoFinishedThread
end
end
#
# Waits until all of the specified threads are terminated. If a block is
# supplied for the method, it is executed for each thread termination.
#
# Raises exceptions in the same manner as +next_wait+.
#
def all_waits
until @threads.empty?
th = next_wait
yield th if block_given?
end
end
end
##
# An alias for ThreadsWait from thwait.rb
ThWait = ThreadsWait
# Documentation comments:
# - Source of documentation is evenly split between Nutshell, existing
# comments, and my own rephrasing.
# - I'm not particularly confident that the comments are all exactly correct.
|
