Module: ThreadLocalAccessors

Defined in:
lib/tlattr_accessors.rb

Instance Method Summary collapse

Instance Method Details

#tlattr_accessor(*names) ⇒ Object

Creates thread-local accessors for the given attribute name.

Example:

tlattr_accessor :my_attr, :another_attr

Default values

You can make the attribute inherit the first value that was set on it in any thread:

tlattr_accessor :my_attr, true

def initialize
  self.my_attr = "foo"
  Thread.new do
     puts self.my_attr # => "foo" (instead of nil)
  end.join
end



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# File 'lib/tlattr_accessors.rb', line 21

def tlattr_accessor(*names)
  first_is_default = names.pop if [true, false].include?(names.last)
  names.each do |name|
    ivar = "@_tlattr_#{name}"
    class_eval %Q{
      def #{name}
        if #{ivar}
          #{ivar}[Thread.current.object_id]
        else
          nil
        end
      end

      def #{name}=(val)
        #{ivar} = Hash.new #{'{|h, k| h[k] = val}' if first_is_default} unless #{ivar}
        thread_id = Thread.current.object_id
        unless #{ivar}.has_key?(thread_id)
          ObjectSpace.define_finalizer(Thread.current, lambda { #{ivar}.delete(thread_id) })
        end
        #{ivar}[thread_id] = val
      end
    }, __FILE__, __LINE__
  end
end