ported from local

MIT-LICENSE

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+Copyright (c) 2010 [name of plugin creator]
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+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.

README

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+SoftDestroyable
+===============
+
+Introduction goes here.
+
+
+Example
+=======
+
+Example goes here.
+
+
+Copyright (c) 2010 [name of plugin creator], released under the MIT license

Rakefile

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+require 'rake'
+require 'rake/testtask'
+require 'rake/rdoctask'
+
+desc 'Default: run unit tests.'
+task :default => :test
+
+desc 'Test the soft_destroyable plugin.'
+Rake::TestTask.new(:test) do |t|
+  t.libs << 'lib'
+  t.libs << 'test'
+  t.pattern = 'test/**/*_test.rb'
+  t.verbose = true
+end
+
+desc 'Generate documentation for the soft_destroyable plugin.'
+Rake::RDocTask.new(:rdoc) do |rdoc|
+  rdoc.rdoc_dir = 'rdoc'
+  rdoc.title    = 'SoftDestroyable'
+  rdoc.options << '--line-numbers' << '--inline-source'
+  rdoc.rdoc_files.include('README')
+  rdoc.rdoc_files.include('lib/**/*.rb')
+end

init.rb

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+require "soft_destroyable"

install.rb

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+# Install hook code here

lib/soft_destroyable.rb

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+require "#{File.dirname(__FILE__)}/soft_destroyable/table_definition"
+require "#{File.dirname(__FILE__)}/soft_destroyable/is_soft_destroyable"
+
+# Allows one to annotate an ActiveRecord module as being soft_destroyable.
+#
+# This changes the behavior of the +destroy+ method to being a soft-destroy, which
+# will set the +deleted_at+ attribute to <tt>Time.now</tt>, and the +deleted+ attribute to <tt>true</tt>
+# It exposes the +revive+ method to reverse the effects of +destroy+.
+# It also exposes the +destroy!+ method which can be used to <b>really</b> destroy an object and it's associations.
+#
+# Standard ActiveRecord destroy callbacks are _not_ called, however you can override +before_soft_destroy+, +after_soft_destroy+,
+# and +before_destroy!+ on your soft_destroyable models.
+#
+# Standard ActiveRecord dependent options :destroy, :restrict, :nullify, :delete_all, and :delete are supported.
+# +revive+ will _not_ undo the effects of +nullify+, +delete_all+, and +delete+.   +restrict+ is _not_ effected by the
+# +deleted?+ state.  In other words, deleted child models will still restrict destroying the parent.
+#
+# The +delete+ operation is _not_ modified by this module.
+#
+# The operations: +destroy+, +destroy!+, and +revive+ are automatically delegated to the dependent association records.
+# in a single transaction.
+#
+# Examples:
+#   class Parent
+#     has_many :children, :dependent => :restrict
+#     has_many :animals, :dependent => :nullify
+#     soft_destroyable
+#
+#
+# Author: Michael Kintzer
+#
+
+module SoftDestroyable
+
+  def self.included(base)
+    base.class_eval do
+      extend ClassMethods
+      extend IsSoftDestroyable
+    end
+  end
+
+  module ClassMethods
+
+    def soft_destroyable(options = {})
+      return if soft_destroyable?
+
+      scope :not_deleted, where(:deleted => false)
+      scope :deleted, where(:deleted => true)
+
+      include InstanceMethods
+      extend SingletonMethods
+    end
+  end
+
+  module SingletonMethods
+
+    # returns an array of association symbols that must be managed by soft_destroyable on
+    # destroy and destroy!
+    def soft_dependencies
+      has_many_dependencies + has_one_dependencies
+    end
+
+    def restrict_dependencies
+      with_restrict_option(:has_many).map(&:name) + with_restrict_option(:has_one).map(&:name)
+    end
+
+    private
+
+    def non_through_dependent_associations(type)
+      reflect_on_all_associations(type).reject { |k, v|
+        k.class == ActiveRecord::Reflection::ThroughReflection }.reject { |k, v| k.options[:dependent].nil? }
+    end
+
+    def has_many_dependencies
+      non_through_dependent_associations(:has_many).map(&:name)
+    end
+
+    def has_one_dependencies
+      non_through_dependent_associations(:has_one).map(&:name)
+    end
+
+    def with_restrict_option(type)
+      non_through_dependent_associations(type).reject { |k, v| k.options[:dependent] != :restrict }
+    end
+
+  end
+
+  module InstanceMethods
+
+    # overrides the normal ActiveRecord::Transactions#destroy.
+    # can be recovered with +revive+
+    def destroy
+      before_soft_destroy
+      result = soft_destroy
+      after_soft_destroy
+      result
+    end
+
+    # not a recoverable operation
+    def destroy!
+      transaction do
+        before_destroy!
+        cascade_destroy!
+        delete
+      end
+    end
+
+    # un-does the effect of +destroy+.  Does not undo nullify on dependents
+    def revive
+      transaction do
+        cascade_revive
+        update_attributes(:deleted_at => nil, :deleted => false)
+      end
+    end
+
+    def soft_dependencies
+      self.class.soft_dependencies
+    end
+
+    def restrict_dependencies
+      self.class.restrict_dependencies
+    end
+
+    # override
+    def before_soft_destroy
+      # empty
+    end
+
+    # override
+    def after_soft_destroy
+      # empty
+    end
+
+    # override
+    def before_destroy!
+      # empty
+    end
+
+    private
+
+    def non_restrict_dependencies
+      soft_dependencies.reject { |assoc_sym| restrict_dependencies.include?(assoc_sym) }
+    end
+
+    def soft_destroy
+      transaction do
+        cascade_soft_destroy
+        update_attributes(:deleted_at => Time.now, :deleted => true)
+      end
+    end
+
+    def cascade_soft_destroy
+      cascade_to_soft_dependents { |assoc_obj|
+        if assoc_obj.respond_to?(:destroy) && assoc_obj.respond_to?(:revive)
+          wrap_with_callbacks(assoc_obj, "soft_destroy") do
+            assoc_obj.destroy
+          end
+        else
+          wrap_with_callbacks(assoc_obj, "soft_destroy") do
+            # no-op
+          end
+        end
+      }
+    end
+
+    def cascade_destroy!
+      cascade_to_soft_dependents { |assoc_obj|
+      # cascade destroy! to soft dependencies objects
+        if assoc_obj.respond_to?(:destroy!)
+          wrap_with_callbacks(assoc_obj, "destroy!") do
+            assoc_obj.destroy!
+          end
+        else
+          wrap_with_callbacks(assoc_obj, "destroy!") do
+            assoc_obj.destroy
+          end
+        end
+      }
+    end
+
+    def cascade_revive
+      cascade_to_soft_dependents { |assoc_obj|
+        assoc_obj.revive if assoc_obj.respond_to?(:revive)
+      }
+    end
+
+    def cascade_to_soft_dependents(&block)
+      return unless block_given?
+
+      # fail fast on :dependent => :restrict
+      restrict_dependencies.each { |assoc_sym| handle_restrict(assoc_sym) }
+
+      non_restrict_dependencies.each do |assoc_sym|
+        reflection  = reflection_for(assoc_sym)
+        association = send(reflection.name)
+
+        case reflection.options[:dependent]
+          when :destroy
+            handle_destroy(reflection, association, &block)
+          when :nullify
+            handle_nullify(reflection, association)
+          when :delete_all
+            handle_delete_all(reflection, association)
+          when :delete
+            handle_delete(reflection, association)
+          else
+        end
+
+      end
+      # reload as dependent associations may have updated
+      reload if self.id
+    end
+
+    def handle_destroy(reflection, association, &block)
+      case reflection.macro
+        when :has_many
+          association.each { |assoc_obj| yield(assoc_obj) }
+        when :has_one
+          # handle non-nil has_one
+          yield(association) if association
+        else
+      end
+    end
+
+    def handle_restrict(assoc_sym)
+      reflection  = reflection_for(assoc_sym)
+      association = send(reflection.name)
+      case reflection.macro
+        when :has_many
+          restrict_on_non_empty_has_many(reflection, association)
+        when :has_one
+          restrict_on_nil_has_one(reflection, association)
+        else
+      end
+    end
+
+    def handle_nullify(reflection, association)
+      return unless association
+      case reflection.macro
+        when :has_many
+          self.class.send(:nullify_has_many_dependencies,
+                          self,
+                          reflection.name,
+                          reflection.klass,
+                          reflection.primary_key_name,
+                          reflection.dependent_conditions(self, self.class, nil))
+        when :has_one
+          association.update_attributes(reflection.primary_key_name => nil)
+        else
+      end
+
+    end
+
+    def handle_delete_all(reflection, association)
+      return unless association
+      self.class.send(:delete_all_has_many_dependencies,
+                      self,
+                      reflection.name,
+                      reflection.klass,
+                      reflection.dependent_conditions(self, self.class, nil))
+    end
+
+    def handle_delete(reflection, association)
+      return unless association
+      association.update_attribute(reflection.primary_key_name, nil)
+    end
+
+    def wrap_with_callbacks(assoc_obj, action)
+      return unless block_given?
+      assoc_obj.send("before_#{action}".to_sym) if assoc_obj.respond_to?("before_#{action}".to_sym)
+      yield
+      assoc_obj.send("after_#{action}".to_sym) if assoc_obj.respond_to?("after_#{action}".to_sym)
+    end
+
+    def reflection_for(assoc_sym)
+      self.class.reflect_on_association(assoc_sym)
+    end
+
+    def restrict_on_non_empty_has_many(reflection, association)
+      return unless association
+      raise ActiveRecord::DeleteRestrictionError.new(reflection) if !association.empty?
+    end
+
+    def restrict_on_nil_has_one(reflection, association)
+      raise ActiveRecord::DeleteRestrictionError.new(reflection) if !association.nil?
+    end
+
+  end
+
+  ActiveRecord::Base.send :include, SoftDestroyable
+  [ActiveRecord::ConnectionAdapters::TableDefinition, ActiveRecord::ConnectionAdapters::Table].each { |base|
+    base.send(:include, SoftDestroyable::TableDefinition)
+  }
+
+  class SoftDestroyError < StandardError
+
+  end
+
+end

lib/soft_destroyable/is_soft_destroyable.rb

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+module SoftDestroyable
+  # Simply adds a flag to determine whether a model class is soft_destroyable.
+  module IsSoftDestroyable
+    def self.extended(base) # :nodoc:
+      base.class_eval do
+        class << self
+          alias_method_chain :soft_destroyable, :flag
+        end
+      end
+    end
+
+    # Overrides the +soft_destroyable+ method to first define the +soft_destroyable?+ class method before
+    # deferring to the original +soft_destroyable+.
+    def soft_destroyable_with_flag(*args)
+      soft_destroyable_without_flag(*args)
+
+      class << self
+        def soft_destroyable?
+          true
+        end
+      end
+    end
+
+    # For all ActiveRecord::Base models that do not call the +soft_destroyable+ method, the +soft_destroyable?+
+    # method will return false.
+    def soft_destroyable?
+      false
+    end
+  end
+end