class Ref::AbstractReferenceValueMap
Abstract base class for WeakValueMap and SoftValueMap.
The classes behave similar to Hashes, but the values in the map are not strong references and can be reclaimed by the garbage collector at any time. When a value is reclaimed, the map entry will be removed.
Public Class Methods
Create a new map. Values added to the map will be cleaned up by the garbage collector if there are no other reference except in the map.
# File lib/ref/abstract_reference_value_map.rb, line 21 def initialize @references = {} @references_to_keys_map = {} @lock = SafeMonitor.new @reference_cleanup = lambda{|object_id| remove_reference_to(object_id)} end
Public Instance Methods
Get a value from the map by key. If the value has been reclaimed by the garbage collector, this will return nil.
# File lib/ref/abstract_reference_value_map.rb, line 30 def [](key) ref = @references[key] value = ref.object if ref value end
Add a key/value to the map.
# File lib/ref/abstract_reference_value_map.rb, line 37 def []=(key, value) ObjectSpace.define_finalizer(value, @reference_cleanup) key = key.dup if key.is_a?(String) @lock.synchronize do @references[key] = self.class.reference_class.new(value) keys_for_id = @references_to_keys_map[value.__id__] unless keys_for_id keys_for_id = [] @references_to_keys_map[value.__id__] = keys_for_id end keys_for_id << key end value end
Clear the map of all key/value pairs.
# File lib/ref/abstract_reference_value_map.rb, line 91 def clear @lock.synchronize do @references.clear @references_to_keys_map.clear end end
Remove the entry associated with the key from the map.
# File lib/ref/abstract_reference_value_map.rb, line 53 def delete(key) ref = @references.delete(key) if ref keys_to_id = @references_to_keys_map[ref.referenced_object_id] if keys_to_id keys_to_id.delete(key) @references_to_keys_map.delete(ref.referenced_object_id) if keys_to_id.empty? end ref.object else nil end end
Iterate through all the key/value pairs in the map that have not been reclaimed by the garbage collector.
# File lib/ref/abstract_reference_value_map.rb, line 83 def each @references.each do |key, ref| value = ref.object yield(key, value) if value end end
# File lib/ref/abstract_reference_value_map.rb, line 105 def inspect live_entries = {} each do |key, value| live_entries[key] = value end live_entries.inspect end
Merge the values from another hash into this map.
# File lib/ref/abstract_reference_value_map.rb, line 99 def merge!(other_hash) other_hash.each do |key, value| self[key] = value end end
Turn the map into an arry of [key, value] entries
# File lib/ref/abstract_reference_value_map.rb, line 75 def to_a array = [] each{|k,v| array << [k, v]} array end
Get the list of all values that have not yet been garbage collected.
# File lib/ref/abstract_reference_value_map.rb, line 68 def values vals = [] each{|k,v| vals << v} vals end
Private Instance Methods
# File lib/ref/abstract_reference_value_map.rb, line 115 def remove_reference_to(object_id) @lock.synchronize do keys = @references_to_keys_map[object_id] if keys keys.each do |key| @references.delete(key) end @references_to_keys_map.delete(object_id) end end end