debian-mirror-gitlab/app/models/concerns/update_project_statistics.rb
2019-07-31 17:26:46 +00:00

60 lines
2.1 KiB
Ruby

# frozen_string_literal: true
# This module is providing helpers for updating `ProjectStatistics` with `after_save` and `before_destroy` hooks.
#
# It deals with `ProjectStatistics.increment_statistic` making sure not to update statistics on a cascade delete from the
# project, and keeping track of value deltas on each save. It updates the DB only when a change is needed.
#
# How to use
# - Invoke `update_project_statistics stat: :a_project_statistics_column, attribute: :an_attr_to_track` in a model class body.
#
# Expectation
# - `attribute` must be an ActiveRecord attribute
# - The model must implement `project` and `project_id`. i.e. direct Project relationship or delegation
module UpdateProjectStatistics
extend ActiveSupport::Concern
class_methods do
attr_reader :statistic_name, :statistic_attribute
# Configure the model to update +stat+ on ProjectStatistics when +attribute+ changes
#
# +stat+:: a column of ProjectStatistics to update
# +attribute+:: an attribute of the current model, default to +:size+
def update_project_statistics(stat:, attribute: :size)
@statistic_name = stat
@statistic_attribute = attribute
after_save(:update_project_statistics_after_save, if: :update_project_statistics_attribute_changed?)
after_destroy(:update_project_statistics_after_destroy, unless: :project_destroyed?)
end
private :update_project_statistics
end
included do
private
def project_destroyed?
project.pending_delete?
end
def update_project_statistics_attribute_changed?
saved_change_to_attribute?(self.class.statistic_attribute)
end
def update_project_statistics_after_save
attr = self.class.statistic_attribute
delta = read_attribute(attr).to_i - attribute_before_last_save(attr).to_i
update_project_statistics(delta)
end
def update_project_statistics_after_destroy
update_project_statistics(-read_attribute(self.class.statistic_attribute).to_i)
end
def update_project_statistics(delta)
ProjectStatistics.increment_statistic(project_id, self.class.statistic_name, delta)
end
end
end