lib/glimmer/data_binding/observable_model.rb
# Copyright (c) 2007-2024 Andy Maleh
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
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# without limitation the rights to use, copy, modify, merge, publish,
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# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
require 'glimmer/data_binding/observable_hashable'
require 'glimmer/data_binding/observer'
module Glimmer
module DataBinding
module ObservableModel
include ObservableHashable
class Notifier
include Observer
def initialize(observable_model, property_name)
@observable_model = observable_model
@property_name = property_name
end
def call(new_value=nil, *extra_args)
@observable_model.notify_observers(@property_name)
end
end
PROPERTY_WRITER_FACTORY = lambda do |property_name, property_writer_name, options|
lambda do |value|
old_value = self.send(property_name)
unregister_dependent_observers(property_name, old_value) # remove dependent observers previously installed in ensure_array_object_observer
self.send("__original__#{property_writer_name}", value)
notify_observers(property_name)
ensure_array_object_observer(property_name, value, old_value, options)
end
end
def add_observer(observer, property_name, options = {})
initialize_observer_options(options)
return observer if has_observer?(observer, property_name)
property_observer_list(property_name) << observer
add_property_writer_observers(property_name, options)
open_struct_loaded = !!::OpenStruct rescue false
add_key_writer_observer(property_name, options) if is_a?(Struct) || (open_struct_loaded && is_a?(OpenStruct))
observer
end
def remove_observer(observer, property_name, options = {})
if has_observer?(observer, property_name)
property_observer_list(property_name).delete(observer)
observer.unobserve(self, property_name)
end
end
def remove_observers(property_name)
property_key = property_name&.to_sym
property_observer_hash[property_key].each do |observer|
remove_observer(observer, property_name)
end
property_observer_hash.delete(property_key)
end
def remove_all_observers
all_observers = property_observer_hash.clone
property_observer_hash.keys.each do |property_name|
remove_observers(property_name)
end
property_observer_hash.clear
all_observers
end
def has_observer?(observer, property_name)
property_observer_list(property_name).include?(observer)
end
def has_observer_for_any_property?(observer)
property_observer_hash.values.map(&:to_a).reduce(:+).include?(observer)
end
def property_observer_hash
@property_observers ||= Concurrent::Hash.new
end
def property_observer_list(property_name)
property_key = property_name&.to_sym
property_observer_hash[property_key] = Concurrent::Set.new unless property_observer_hash[property_key]
property_observer_hash[property_key]
end
alias key_observer_list property_observer_list
def all_property_observer_list
property_observer_list(nil)
end
alias all_key_observer_list all_property_observer_list
def notify_observers(property_name)
property_observer_list(property_name).to_a.each { |observer| observer.call(send(property_name)) }
end
def add_property_writer_observers(property_name, options)
options[:attribute_writer_type].each do |attribute_writer_type|
begin
property_writer_name = attribute_writer_type.to_s.gsub('attribute', property_name.to_s)
method(property_writer_name)
ensure_array_object_observer(property_name, send(property_name), nil, options)
begin
method("__original__#{property_writer_name}")
rescue
define_singleton_method("__original__#{property_writer_name}", property_writer_method(property_writer_name))
# Note the limitation that the first observe call options apply to all subsequent observations meaning even if unobserve was called, options do not change from initial ones
# It is good enough for now. If there is a need to address this in the future, this is where to start the work
define_singleton_method(property_writer_name, &PROPERTY_WRITER_FACTORY.call(property_name, property_writer_name, options))
end
rescue => e
#ignore writing if no property writer exists
Glimmer::Config.logger.debug {"No need to observe property writer: #{property_writer_name}\n#{e.message}\n#{e.backtrace.join("\n")}"}
end
end
end
def property_writer_method(property_writer_name)
self.class.instance_method(property_writer_name) rescue self.method(property_writer_name)
end
def unregister_dependent_observers(property_name, old_value)
# TODO look into optimizing this
return unless old_value.is_a?(ObservableModel) || old_value.is_a?(ObservableArray)
property_observer_list(property_name).each { |observer| observer.unregister_dependents_with_observable(observer.registration_for(self, property_name), old_value) }
end
alias deregister_dependent_observers unregister_dependent_observers
def ensure_array_object_observer(property_name, object, old_object = nil, options = nil)
options ||= {}
return unless object&.is_a?(Array)
array_object_observer = array_object_observer_for(property_name)
array_observer_registration = array_object_observer.observe(object, options)
property_observer_list(property_name).each do |observer|
my_registration = observer.registration_for(self, property_name) # TODO eliminate repetition
observer.add_dependent(my_registration => array_observer_registration)
end
array_object_observer_for(property_name).unregister(old_object) if old_object.is_a?(ObservableArray)
end
def array_object_observer_for(property_name)
@array_object_observers ||= Concurrent::Hash.new
@array_object_observers[property_name] = Notifier.new(self, property_name) unless @array_object_observers.has_key?(property_name)
@array_object_observers[property_name]
end
def initialize_observer_options(options)
options[:attribute_writer_type] ||= [:attribute=]
options[:attribute_writer_type] = [options[:attribute_writer_type]] if !options[:attribute_writer_type].is_a?(Array)
end
end
end
end