Class: ObjectSpace::WeakKeyMap

Inherits:
Object
  • Object
show all
Defined in:
lib/weak_key_map/impl.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ WeakKeyMap

Returns a new instance of WeakKeyMap.



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# File 'lib/weak_key_map/impl.rb', line 7

def initialize
  @map = {}
  @refs = {}
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/weak_key_map/impl.rb', line 12

def [](key)
  hash = key.hash
  ref = @refs[hash]
  return nil unless ref
  return @map[hash] if ref.weakref_alive?

  @map.delete(hash)
  @refs.delete(hash)

  nil
end

#[]=(key, value) ⇒ Object 



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# File 'lib/weak_key_map/impl.rb', line 24

def []=(key, value)
  case key
  when true, false, nil, Integer, Float, Symbol
    raise ArgumentError, "WeakKeyMap keys must be garbage collectable"
  end

  hash = key.hash
  @refs[hash] = WeakRef.new(key)
  @map[hash] = value
end

#clear ⇒ Object 



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# File 'lib/weak_key_map/impl.rb', line 39

def clear
  @map.clear
  @refs.clear
  self
end

#delete(key, &block) ⇒ Object 



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# File 'lib/weak_key_map/impl.rb', line 45

def delete(key, &block)
  hash = key.hash
  retval = nil

  if @refs.key?(hash)
    retval = @map[hash]
  end

  if block_given?
    retval = yield key
  end

  @refs.delete(hash)
  @map.delete(hash)

  retval
end

#getkey(key) ⇒ Object 



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# File 'lib/weak_key_map/impl.rb', line 63

def getkey(key)
  hash = key.hash

  if @refs.key?(hash)
    ref = @refs[hash]

    begin
      return ref.__getobj__
    rescue WeakRef::RefError
      @refs.delete(hash)
      @map.delete(hash)
    end
  end

  nil
end

#inspect ⇒ Object 



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# File 'lib/weak_key_map/impl.rb', line 35

def inspect
  "#<#{self.class}:0x#{(object_id << 1).to_s(16).rjust(14, '0')} size=#{@map.size}>"
end

#key?(key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/weak_key_map/impl.rb', line 80

def key?(key)
  hash = key.hash

  if @refs.key?(hash)
    ref = @refs[hash]
    return true if ref.weakref_alive?

    @refs.delete(hash)
    @map.delete(hash)
  end

  false
end

#size ⇒ Object Also known as: length 



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# File 'lib/weak_key_map/impl.rb', line 94

def size
  @refs.size
end