Semaphore

Technically a semaphore is simply an integer variable which has an execution queue associated with it.

Methods
Public Class methods
new(initvalue = 0)

[ show source ]

# File lib/facets/more/semaphore.rb, line 29
  def initialize(initvalue = 0)
    @counter = initvalue
    @waiting_list = []
  end
Public Instance methods
down()

Alias for wait

exclusive() {|| ...}
This method is also aliased as synchronize

[ show source ]

# File lib/facets/more/semaphore.rb, line 65
  def exclusive
    wait
    yield
  ensure
    signal
  end
p()

Alias for wait

signal()
This method is also aliased as up v

[ show source ]

# File lib/facets/more/semaphore.rb, line 45
  def signal
    Thread.critical = true
    begin
      if (@counter += 1) <= 0
        t = @waiting_list.shift
        t.wakeup if t
      end
    rescue ThreadError
      retry
    end
    self
  ensure
    Thread.critical = false
  end
synchronize()

Alias for exclusive

up()

Alias for signal

v()

Alias for signal

wait()
This method is also aliased as down p

[ show source ]

# File lib/facets/more/semaphore.rb, line 34
  def wait
    Thread.critical = true
    if (@counter -= 1) < 0
      @waiting_list.push(Thread.current)
      Thread.stop
    end
    self
  ensure
    Thread.critical = false
  end