diff options
Diffstat (limited to 'lib/thread.rb')
| -rw-r--r-- | lib/thread.rb | 420 |
1 files changed, 0 insertions, 420 deletions
diff --git a/lib/thread.rb b/lib/thread.rb deleted file mode 100644 index 8b27356c48..0000000000 --- a/lib/thread.rb +++ /dev/null @@ -1,420 +0,0 @@ -# -# thread.rb - thread support classes -# $Date$ -# by Yukihiro Matsumoto <matz@netlab.co.jp> -# -# Copyright (C) 2001 Yukihiro Matsumoto -# Copyright (C) 2000 Network Applied Communication Laboratory, Inc. -# Copyright (C) 2000 Information-technology Promotion Agency, Japan -# - -unless defined? Thread - fail "Thread not available for this ruby interpreter" -end - -unless defined? ThreadError - class ThreadError<StandardError - end -end - -if $DEBUG - Thread.abort_on_exception = true -end - -class Thread - # - # FIXME: not documented in Pickaxe or Nutshell. - # - def Thread.exclusive - _old = Thread.critical - begin - Thread.critical = true - return yield - ensure - Thread.critical = _old - end - end -end - -# -# +Mutex+ implements a simple semaphore that can be used to coordinate access to -# shared data from multiple concurrent threads. -# -# Example: -# -# require 'thread' -# semaphore = Mutex.new -# -# a = Thread.new { -# semaphore.synchronize { -# # access shared resource -# } -# } -# -# b = Thread.new { -# semaphore.synchronize { -# # access shared resource -# } -# } -# -class Mutex - def initialize - @waiting = [] - @locked = false; - @waiting.taint # enable tainted comunication - self.taint - end - - # - # Returns +true+ if this lock is currently held by some thread. - # - def locked? - @locked - end - - # - # Attempts to obtain the lock and returns immediately. Returns +true+ if the - # lock was granted. - # - def try_lock - result = false - Thread.critical = true - unless @locked - @locked = true - result = true - end - Thread.critical = false - result - end - - # - # Attempts to grab the lock and waits if it isn't available. - # - def lock - while (Thread.critical = true; @locked) - @waiting.push Thread.current - Thread.stop - end - @locked = true - Thread.critical = false - self - end - - # - # Releases the lock. Returns +nil+ if ref wasn't locked. - # - def unlock - return unless @locked - Thread.critical = true - @locked = false - begin - t = @waiting.shift - t.wakeup if t - rescue ThreadError - retry - end - Thread.critical = false - begin - t.run if t - rescue ThreadError - end - self - end - - # - # Obtains a lock, runs the block, and releases the lock when the block - # completes. See the example under +Mutex+. - # - def synchronize - lock - begin - yield - ensure - unlock - end - end - - # - # FIXME: not documented in Pickaxe/Nutshell. - # - def exclusive_unlock - return unless @locked - Thread.exclusive do - @locked = false - begin - t = @waiting.shift - t.wakeup if t - rescue ThreadError - retry - end - yield - end - self - end -end - -# -# +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 (see the discussion on page 117). -# -# 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 -# } -# } -# -class ConditionVariable - def initialize - @waiters = [] - end - - # - # Releases the lock held in +mutex+ and waits; reacquires the lock on wakeup. - # - def wait(mutex) - begin - mutex.exclusive_unlock do - @waiters.push(Thread.current) - Thread.stop - end - ensure - mutex.lock - end - end - - # - # Wakes up the first thread in line waiting for this lock. - # - def signal - begin - t = @waiters.shift - t.run if t - rescue ThreadError - retry - end - end - - # - # Wakes up all threads waiting for this lock. - # - def broadcast - waiters0 = nil - Thread.exclusive do - waiters0 = @waiters.dup - @waiters.clear - end - for t in waiters0 - begin - t.run - rescue ThreadError - end - end - end -end - -# -# This class provides a way to communicate data between threads. -# -# TODO: an example (code or English) would really help here. How do you set up -# a queue between two threads? -# -class Queue - # - # Creates a new queue. - # - def initialize - @que = [] - @waiting = [] - @que.taint # enable tainted comunication - @waiting.taint - self.taint - end - - # - # Pushes +obj+ to the queue. - # - def push(obj) - Thread.critical = true - @que.push obj - begin - t = @waiting.shift - t.wakeup if t - rescue ThreadError - retry - ensure - Thread.critical = false - end - begin - t.run if t - rescue ThreadError - end - end - alias << push - alias enq push - - # - # Retrieves data from the queue. If the queue is empty, the calling thread is - # suspended until data is pushed onto the queue. If +non_block+ is true, the - # thread isn't suspended, and an exception is raised. - # - def pop(non_block=false) - while (Thread.critical = true; @que.empty?) - raise ThreadError, "queue empty" if non_block - @waiting.push Thread.current - Thread.stop - end - @que.shift - ensure - Thread.critical = false - end - alias shift pop - alias deq pop - - # - # Returns +true+ is the queue is empty. - # - def empty? - @que.empty? - end - - # - # Removes all objects from the queue. - # - def clear - @que.clear - end - - # - # Returns the length of the queue. - # - def length - @que.length - end - - # - # Alias of length. - # - def size - length - end - - # - # Returns the number of threads waiting on the queue. - # - def num_waiting - @waiting.size - end -end - -# -# This class represents queues of specified size capacity. The +push+ operation -# may be blocked if the capacity is full. -# -class SizedQueue<Queue - # - # Creates a fixed-length queue with a maximum size of +max+. - # - def initialize(max) - raise ArgumentError, "queue size must be positive" unless max > 0 - @max = max - @queue_wait = [] - @queue_wait.taint # enable tainted comunication - super() - end - - # - # Returns the maximum size of the queue. - # - def max - @max - end - - # - # Sets the maximum size of the queue. - # - def max=(max) - Thread.critical = true - if max <= @max - @max = max - Thread.critical = false - else - diff = max - @max - @max = max - Thread.critical = false - diff.times do - begin - t = @queue_wait.shift - t.run if t - rescue ThreadError - retry - end - end - end - max - end - - def push(obj) - Thread.critical = true - while @que.length >= @max - @queue_wait.push Thread.current - Thread.stop - Thread.critical = true - end - super - end - alias << push - alias enq push - - def pop(*args) - retval = super - Thread.critical = true - if @que.length < @max - begin - t = @queue_wait.shift - t.wakeup if t - rescue ThreadError - retry - ensure - Thread.critical = false - end - begin - t.run if t - rescue ThreadError - end - end - retval - end - alias shift pop - alias deq pop - - def num_waiting - @waiting.size + @queue_wait.size - end -end - -# Documentation comments: -# - SizedQueue #push and #pop deserve some documentation, as they are different -# from the Queue implementations. -# - Some methods are not documented in Pickaxe/Nutshell, and are therefore not -# documented here. See FIXME notes. -# - Reference to Pickaxe page numbers should be replaced with either a section -# name or a summary. -# - How do you document aliases? -# - How do you make RDoc inherit documentation from superclass? |