Class: Foobara::WeakObjectSet

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
foobara-0.2.7/projects/weak_object_set/src/weak_object_set.rb,
foobara-0.2.7/projects/weak_object_set/lib/foobara/weak_object_set.rb

Overview

TODO: a possible optimization: have a certain number of records before the Weakref approach kicks in that way we don’t just immediately clear out useful information without any actual memory burden

Defined Under Namespace

Classes: GarbageCleaner

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key_method = nil) ⇒ WeakObjectSet

Returns a new instance of WeakObjectSet.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 90

def initialize(key_method = nil)
  self.key_method = key_method
  self.monitor = Monitor.new
  clear
end

Instance Attribute Details

#closed ⇒ Object

Returns the value of attribute closed.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 87

def closed
  @closed
end

#garbage_cleaner ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 152

def garbage_cleaner
  @garbage_cleaner ||= begin
    queue = Queue.new

    GarbageCleaner.new(self, queue)
  end
end

#key_method ⇒ Object

Returns the value of attribute key_method.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 87

def key_method
  @key_method
end

#key_to_object_id ⇒ Object

Returns the value of attribute key_to_object_id.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 87

def key_to_object_id
  @key_to_object_id
end

#monitor ⇒ Object

Returns the value of attribute monitor.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 87

def monitor
  @monitor
end

#object_id_to_key ⇒ Object

Returns the value of attribute object_id_to_key.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 87

def object_id_to_key
  @object_id_to_key
end

#objects ⇒ Object

Returns the value of attribute objects.



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 87

def objects
  @objects
end

Instance Method Details

#<<(object) ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 160

def <<(object)
  if closed?
    # :nocov:
    raise "Cannot add objects to a closed WeakObjectSet"
    # :nocov:
  end

  object_id = object.object_id

  monitor.synchronize do
    existing_object = self[object_id]

    if existing_object
      if key_method
        key = object.send(key_method)
        old_key = object_id_to_key[object_id]

        if key != old_key
          key_to_object_id.delete(old_key)

          if key
            key_to_object_id[key] = object_id
            object_id_to_key[object_id] = key
          else
            object_id_to_key.delete(object_id)
          end
        end
      end
    else
      garbage_cleaner.track(object)

      if key_method
        key = object.send(key_method)

        if key
          existing_record_object_id = key_to_object_id[key]

          if existing_record_object_id
            # Sometimes this path is hit in the test suite and sometimes not, depending on
            # non-deterministic behavior of the garbage collector
            # :nocov:
            delete(existing_record_object_id)
            # :nocov:
          end

          key_to_object_id[key] = object_id
          object_id_to_key[object_id] = key
        end
      end

      objects[object_id] = WeakRef.new(object)

      object
    end
  end
end

#[](object_or_object_id) ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 96

def [](object_or_object_id)
  monitor.synchronize do
    ref = ref_for(object_or_object_id)

    # TODO: is this necessary? Why not check weakref_alive? now that we're in a mutex?
    object = begin
      ref&.__getobj__
    rescue WeakRef::RefError
      # :nocov:
      nil
      # :nocov:
    end

    if ref&.weakref_alive?
      object
    end
  end
end

#clear ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 273

def clear
  monitor.synchronize do
    stop_garbage_cleaner

    self.objects = {}

    if key_method
      self.key_to_object_id = {}
      self.object_id_to_key = {}
    end
  end
end

#close ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 253

def close
  raise if closed?

  self.closed = true
  stop_garbage_cleaner
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'projects/weak_object_set/src/weak_object_set.rb', line 286

def closed?
  closed
end

#delete(object_or_object_id) ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 217

def delete(object_or_object_id)
  object_id = if object_or_object_id.is_a?(::Integer)
                object_or_object_id
              else
                object_or_object_id.object_id
              end

  monitor.synchronize do
    if key_method
      key = object_id_to_key.delete(object_id)

      if key
        key_to_object_id.delete(key)
      end
    end

    objects.delete(object_id)
  end
end

#each ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 125

def each
  monitor.synchronize do
    objects.each_value do |ref|
      # Is this still necessary now that we're in a mutex?
      object = begin
        ref.__getobj__
      rescue WeakRef::RefError
        nil
      end

      if ref.weakref_alive?
        yield object
      end
    end
  end
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'projects/weak_object_set/src/weak_object_set.rb', line 146

def empty?
  monitor.synchronize do
    objects.empty? || objects.values.none?(&:weakref_alive?)
  end
end

#find_by_key(key) ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 237

def find_by_key(key)
  monitor.synchronize do
    unless key_method
      # :nocov:
      raise "Cannot find by key if there was no key_method given."
      # :nocov:
    end

    object_id = key_to_object_id[key]

    if object_id
      self[object_id]
    end
  end
end

#ref_for(object_or_object_id) ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 115

def ref_for(object_or_object_id)
  object_id = if object_or_object_id.is_a?(::Integer)
                object_or_object_id
              else
                object_or_object_id.object_id
              end

  objects[object_id]
end

#size ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 142

def size
  count
end

#stop_garbage_cleaner ⇒ Object 



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# File 'projects/weak_object_set/src/weak_object_set.rb', line 260

def stop_garbage_cleaner
  gc = nil

  monitor.synchronize do
    if @garbage_cleaner
      gc = garbage_cleaner
      self.garbage_cleaner = nil
    end
  end

  gc&.deactivate
end