Class: File

Inherits:
Object show all
Defined in:
lib/vendor/puppet/external/lock.rb

Instance Method Summary collapse

Instance Method Details

#lock_exclusive ⇒ Object

Get an exclusive (i.e., write) lock on the file, and yield to the block. If the lock is not available, wait for it without blocking other ruby threads.



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# File 'lib/vendor/puppet/external/lock.rb', line 21

def lock_exclusive
  if Thread.list.size == 1
    flock(LOCK_EX)
  else
    # ugly hack because waiting for a lock in a Ruby thread blocks the
    # process
    period = 0.001
    until flock(LOCK_EX|LOCK_NB)
      sleep period
      period *= 2 if period < 1
    end
  end

  yield self
ensure
  flush
  flock(LOCK_UN)
end

#lock_shared ⇒ Object

Get a shared (i.e., read) lock on the file, and yield to the block. If the lock is not available, wait for it without blocking other ruby threads.



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# File 'lib/vendor/puppet/external/lock.rb', line 43

def lock_shared
  if Thread.list.size == 1
    flock(LOCK_SH)
  else
    # ugly hack because waiting for a lock in a Ruby thread blocks the
    # process
    period = 0.001
    until flock(LOCK_SH|LOCK_NB)
      sleep period
      period *= 2 if period < 1
    end
  end

  yield self
ensure
  Thread.exclusive {flock(LOCK_UN) if $reader_count[self.stat.ino] == 1}
  ## for solaris, no need to unlock here--closing does it
  ## but this has no effect on the bug
end