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module Tins
module Once
include File::Constants
module_function
def only_once(lock_filename = nil, locking_constant = nil)
lock_filename ||= $0
locking_constant ||= LOCK_EX
f = File.new(lock_filename, RDONLY)
f.flock(locking_constant) and yield
ensure
if f
f.flock LOCK_UN
f.close
end
end
def try_only_once(lock_filename = nil, locking_constant = nil, &block)
only_once(lock_filename, locking_constant || LOCK_EX | LOCK_NB, &block)
end
end
end
require 'tins/alias'
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