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- # Copyright (c) 2005 Rick Olson
- #
- # 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.
-
- module ActiveRecord #:nodoc:
- module Acts #:nodoc:
- # Specify this act if you want to save a copy of the row in a versioned table. This assumes there is a
- # versioned table ready and that your model has a version field. This works with optimistic locking if the lock_version
- # column is present as well.
- #
- # The class for the versioned model is derived the first time it is seen. Therefore, if you change your database schema you have to restart
- # your container for the changes to be reflected. In development mode this usually means restarting WEBrick.
- #
- # class Page < ActiveRecord::Base
- # # assumes pages_versions table
- # acts_as_versioned
- # end
- #
- # Example:
- #
- # page = Page.create(:title => 'hello world!')
- # page.version # => 1
- #
- # page.title = 'hello world'
- # page.save
- # page.version # => 2
- # page.versions.size # => 2
- #
- # page.revert_to(1) # using version number
- # page.title # => 'hello world!'
- #
- # page.revert_to(page.versions.last) # using versioned instance
- # page.title # => 'hello world'
- #
- # page.versions.earliest # efficient query to find the first version
- # page.versions.latest # efficient query to find the most recently created version
- #
- #
- # Simple Queries to page between versions
- #
- # page.versions.before(version)
- # page.versions.after(version)
- #
- # Access the previous/next versions from the versioned model itself
- #
- # version = page.versions.latest
- # version.previous # go back one version
- # version.next # go forward one version
- #
- # See ActiveRecord::Acts::Versioned::ClassMethods#acts_as_versioned for configuration options
- module Versioned
- CALLBACKS = [:set_new_version, :save_version_on_create, :save_version?, :clear_altered_attributes]
- def self.included(base) # :nodoc:
- base.extend ClassMethods
- end
-
- module ClassMethods
- # == Configuration options
- #
- # * <tt>class_name</tt> - versioned model class name (default: PageVersion in the above example)
- # * <tt>table_name</tt> - versioned model table name (default: page_versions in the above example)
- # * <tt>foreign_key</tt> - foreign key used to relate the versioned model to the original model (default: page_id in the above example)
- # * <tt>inheritance_column</tt> - name of the column to save the model's inheritance_column value for STI. (default: versioned_type)
- # * <tt>version_column</tt> - name of the column in the model that keeps the version number (default: version)
- # * <tt>sequence_name</tt> - name of the custom sequence to be used by the versioned model.
- # * <tt>limit</tt> - number of revisions to keep, defaults to unlimited
- # * <tt>if</tt> - symbol of method to check before saving a new version. If this method returns false, a new version is not saved.
- # For finer control, pass either a Proc or modify Model#version_condition_met?
- #
- # acts_as_versioned :if => Proc.new { |auction| !auction.expired? }
- #
- # or...
- #
- # class Auction
- # def version_condition_met? # totally bypasses the <tt>:if</tt> option
- # !expired?
- # end
- # end
- #
- # * <tt>if_changed</tt> - Simple way of specifying attributes that are required to be changed before saving a model. This takes
- # either a symbol or array of symbols. WARNING - This will attempt to overwrite any attribute setters you may have.
- # Use this instead if you want to write your own attribute setters (and ignore if_changed):
- #
- # def name=(new_name)
- # write_changed_attribute :name, new_name
- # end
- #
- # * <tt>extend</tt> - Lets you specify a module to be mixed in both the original and versioned models. You can also just pass a block
- # to create an anonymous mixin:
- #
- # class Auction
- # acts_as_versioned do
- # def started?
- # !started_at.nil?
- # end
- # end
- # end
- #
- # or...
- #
- # module AuctionExtension
- # def started?
- # !started_at.nil?
- # end
- # end
- # class Auction
- # acts_as_versioned :extend => AuctionExtension
- # end
- #
- # Example code:
- #
- # @auction = Auction.find(1)
- # @auction.started?
- # @auction.versions.first.started?
- #
- # == Database Schema
- #
- # The model that you're versioning needs to have a 'version' attribute. The model is versioned
- # into a table called #{model}_versions where the model name is singlular. The _versions table should
- # contain all the fields you want versioned, the same version column, and a #{model}_id foreign key field.
- #
- # A lock_version field is also accepted if your model uses Optimistic Locking. If your table uses Single Table inheritance,
- # then that field is reflected in the versioned model as 'versioned_type' by default.
- #
- # Acts_as_versioned comes prepared with the ActiveRecord::Acts::Versioned::ActMethods::ClassMethods#create_versioned_table
- # method, perfect for a migration. It will also create the version column if the main model does not already have it.
- #
- # class AddVersions < ActiveRecord::Migration
- # def self.up
- # # create_versioned_table takes the same options hash
- # # that create_table does
- # Post.create_versioned_table
- # end
- #
- # def self.down
- # Post.drop_versioned_table
- # end
- # end
- #
- # == Changing What Fields Are Versioned
- #
- # By default, acts_as_versioned will version all but these fields:
- #
- # [self.primary_key, inheritance_column, 'version', 'lock_version', versioned_inheritance_column]
- #
- # You can add or change those by modifying #non_versioned_columns. Note that this takes strings and not symbols.
- #
- # class Post < ActiveRecord::Base
- # acts_as_versioned
- # self.non_versioned_columns << 'comments_count'
- # end
- #
- def acts_as_versioned(options = {}, &extension)
- # don't allow multiple calls
- return if self.included_modules.include?(ActiveRecord::Acts::Versioned::ActMethods)
-
- send :include, ActiveRecord::Acts::Versioned::ActMethods
-
- cattr_accessor :versioned_class_name, :versioned_foreign_key, :versioned_table_name, :versioned_inheritance_column,
- :version_column, :max_version_limit, :track_altered_attributes, :version_condition, :version_sequence_name, :non_versioned_columns,
- :version_association_options
-
- # legacy
- alias_method :non_versioned_fields, :non_versioned_columns
- alias_method :non_versioned_fields=, :non_versioned_columns=
-
- class << self
- alias_method :non_versioned_fields, :non_versioned_columns
- alias_method :non_versioned_fields=, :non_versioned_columns=
- end
-
- send :attr_accessor, :altered_attributes
-
- self.versioned_class_name = options[:class_name] || "Version"
- self.versioned_foreign_key = options[:foreign_key] || self.to_s.foreign_key
- self.versioned_table_name = options[:table_name] || "#{table_name_prefix}#{base_class.name.demodulize.underscore}_versions#{table_name_suffix}"
- self.versioned_inheritance_column = options[:inheritance_column] || "versioned_#{inheritance_column}"
- self.version_column = options[:version_column] || 'version'
- self.version_sequence_name = options[:sequence_name]
- self.max_version_limit = options[:limit].to_i
- self.version_condition = options[:if] || true
- self.non_versioned_columns = [self.primary_key, inheritance_column, 'version', 'lock_version', versioned_inheritance_column]
- self.version_association_options = {
- :class_name => "#{self.to_s}::#{versioned_class_name}",
- :foreign_key => versioned_foreign_key,
- :dependent => :delete_all
- }.merge(options[:association_options] || {})
-
- if block_given?
- extension_module_name = "#{versioned_class_name}Extension"
- silence_warnings do
- self.const_set(extension_module_name, Module.new(&extension))
- end
-
- options[:extend] = self.const_get(extension_module_name)
- end
-
- class_eval do
- has_many :versions, version_association_options do
- # finds earliest version of this record
- def earliest
- @earliest ||= order('version').first
- end
-
- # find latest version of this record
- def latest
- @latest ||= order('version desc').first
- end
- end
- before_save :set_new_version
- after_create :save_version_on_create
- after_update :save_version
- after_save :clear_old_versions
- after_save :clear_altered_attributes
-
- unless options[:if_changed].nil?
- self.track_altered_attributes = true
- options[:if_changed] = [options[:if_changed]] unless options[:if_changed].is_a?(Array)
- options[:if_changed].each do |attr_name|
- define_method("#{attr_name}=") do |value|
- write_changed_attribute attr_name, value
- end
- end
- end
-
- include options[:extend] if options[:extend].is_a?(Module)
- end
-
- # create the dynamic versioned model
- const_set(versioned_class_name, Class.new(ActiveRecord::Base)).class_eval do
- def self.reloadable? ; false ; end
- # find first version before the given version
- def self.before(version)
- order('version desc').
- where("#{original_class.versioned_foreign_key} = ? and version < ?", version.send(original_class.versioned_foreign_key), version.version).
- first
- end
-
- # find first version after the given version.
- def self.after(version)
- order('version').
- where("#{original_class.versioned_foreign_key} = ? and version > ?", version.send(original_class.versioned_foreign_key), version.version).
- first
- end
-
- def previous
- self.class.before(self)
- end
-
- def next
- self.class.after(self)
- end
-
- def versions_count
- page.version
- end
- end
-
- versioned_class.cattr_accessor :original_class
- versioned_class.original_class = self
- versioned_class.table_name = versioned_table_name
- versioned_class.belongs_to self.to_s.demodulize.underscore.to_sym,
- :class_name => "::#{self.to_s}",
- :foreign_key => versioned_foreign_key
- versioned_class.send :include, options[:extend] if options[:extend].is_a?(Module)
- versioned_class.set_sequence_name version_sequence_name if version_sequence_name
- end
- end
-
- module ActMethods
- def self.included(base) # :nodoc:
- base.extend ClassMethods
- end
-
- # Finds a specific version of this record
- def find_version(version = nil)
- self.class.find_version(id, version)
- end
-
- # Saves a version of the model if applicable
- def save_version
- save_version_on_create if save_version?
- end
-
- # Saves a version of the model in the versioned table. This is called in the after_save callback by default
- def save_version_on_create
- rev = self.class.versioned_class.new
- self.clone_versioned_model(self, rev)
- rev.version = send(self.class.version_column)
- rev.send("#{self.class.versioned_foreign_key}=", self.id)
- rev.save
- end
-
- # Clears old revisions if a limit is set with the :limit option in <tt>acts_as_versioned</tt>.
- # Override this method to set your own criteria for clearing old versions.
- def clear_old_versions
- return if self.class.max_version_limit == 0
- excess_baggage = send(self.class.version_column).to_i - self.class.max_version_limit
- if excess_baggage > 0
- sql = "DELETE FROM #{self.class.versioned_table_name} WHERE version <= #{excess_baggage} AND #{self.class.versioned_foreign_key} = #{self.id}"
- self.class.versioned_class.connection.execute sql
- end
- end
-
- def versions_count
- version
- end
-
- # Reverts a model to a given version. Takes either a version number or an instance of the versioned model
- def revert_to(version)
- if version.is_a?(self.class.versioned_class)
- return false unless version.send(self.class.versioned_foreign_key) == self.id and !version.new_record?
- else
- return false unless version = versions.find_by_version(version)
- end
- self.clone_versioned_model(version, self)
- self.send("#{self.class.version_column}=", version.version)
- true
- end
-
- # Reverts a model to a given version and saves the model.
- # Takes either a version number or an instance of the versioned model
- def revert_to!(version)
- revert_to(version) ? save_without_revision : false
- end
-
- # Temporarily turns off Optimistic Locking while saving. Used when reverting so that a new version is not created.
- def save_without_revision
- save_without_revision!
- true
- rescue
- false
- end
-
- def save_without_revision!
- without_locking do
- without_revision do
- save!
- end
- end
- end
-
- # Returns an array of attribute keys that are versioned. See non_versioned_columns
- def versioned_attributes
- self.attributes.keys.select { |k| !self.class.non_versioned_columns.include?(k) }
- end
-
- # If called with no parameters, gets whether the current model has changed and needs to be versioned.
- # If called with a single parameter, gets whether the parameter has changed.
- def changed?(attr_name = nil)
- attr_name.nil? ?
- (!self.class.track_altered_attributes || (altered_attributes && altered_attributes.length > 0)) :
- (altered_attributes && altered_attributes.include?(attr_name.to_s))
- end
-
- # keep old dirty? method
- alias_method :dirty?, :changed?
-
- # Clones a model. Used when saving a new version or reverting a model's version.
- def clone_versioned_model(orig_model, new_model)
- self.versioned_attributes.each do |key|
- new_model.send("#{key}=", orig_model.send(key)) if orig_model.respond_to?(key)
- end
-
- if self.class.columns_hash.include?(self.class.inheritance_column)
- if orig_model.is_a?(self.class.versioned_class)
- new_model[new_model.class.inheritance_column] = orig_model[self.class.versioned_inheritance_column]
- elsif new_model.is_a?(self.class.versioned_class)
- new_model[self.class.versioned_inheritance_column] = orig_model[orig_model.class.inheritance_column]
- end
- end
- end
-
- # Checks whether a new version shall be saved or not. Calls <tt>version_condition_met?</tt> and <tt>changed?</tt>.
- def save_version?
- version_condition_met? && changed?
- end
-
- # Checks condition set in the :if option to check whether a revision should be created or not. Override this for
- # custom version condition checking.
- def version_condition_met?
- case
- when version_condition.is_a?(Symbol)
- send(version_condition)
- when version_condition.respond_to?(:call) && (version_condition.arity == 1 || version_condition.arity == -1)
- version_condition.call(self)
- else
- version_condition
- end
- end
-
- # Executes the block with the versioning callbacks disabled.
- #
- # @foo.without_revision do
- # @foo.save
- # end
- #
- def without_revision(&block)
- self.class.without_revision(&block)
- end
-
- # Turns off optimistic locking for the duration of the block
- #
- # @foo.without_locking do
- # @foo.save
- # end
- #
- def without_locking(&block)
- self.class.without_locking(&block)
- end
-
- def empty_callback() end #:nodoc:
-
- protected
- # sets the new version before saving, unless you're using optimistic locking. In that case, let it take care of the version.
- def set_new_version
- self.send("#{self.class.version_column}=", self.next_version) if new_record? || (!locking_enabled? && save_version?)
- end
-
- # Gets the next available version for the current record, or 1 for a new record
- def next_version
- return 1 if new_record?
- (versions.maximum('version') || 0) + 1
- end
-
- # clears current changed attributes. Called after save.
- def clear_altered_attributes
- self.altered_attributes = []
- end
-
- def write_changed_attribute(attr_name, attr_value)
- # Convert to db type for comparison. Avoids failing Float<=>String comparisons.
- attr_value_for_db = self.class.columns_hash[attr_name.to_s].type_cast_from_database(attr_value)
- (self.altered_attributes ||= []) << attr_name.to_s unless self.changed?(attr_name) || self.send(attr_name) == attr_value_for_db
- write_attribute(attr_name, attr_value_for_db)
- end
-
- module ClassMethods
- # Finds a specific version of a specific row of this model
- def find_version(id, version = nil)
- return find(id) unless version
-
- conditions = ["#{versioned_foreign_key} = ? AND version = ?", id, version]
- options = { :conditions => conditions, :limit => 1 }
-
- if result = find_versions(id, options).first
- result
- else
- raise RecordNotFound, "Couldn't find #{name} with ID=#{id} and VERSION=#{version}"
- end
- end
-
- # Finds versions of a specific model. Takes an options hash like <tt>find</tt>
- def find_versions(id, options = {})
- versioned_class.all({
- :conditions => ["#{versioned_foreign_key} = ?", id],
- :order => 'version' }.merge(options))
- end
-
- # Returns an array of columns that are versioned. See non_versioned_columns
- def versioned_columns
- self.columns.select { |c| !non_versioned_columns.include?(c.name) }
- end
-
- # Returns an instance of the dynamic versioned model
- def versioned_class
- const_get versioned_class_name
- end
-
- # Rake migration task to create the versioned table using options passed to acts_as_versioned
- def create_versioned_table(create_table_options = {})
- # create version column in main table if it does not exist
- if !self.content_columns.find { |c| %w(version lock_version).include? c.name }
- self.connection.add_column table_name, :version, :integer
- end
-
- self.connection.create_table(versioned_table_name, create_table_options) do |t|
- t.column versioned_foreign_key, :integer
- t.column :version, :integer
- end
-
- updated_col = nil
- self.versioned_columns.each do |col|
- updated_col = col if !updated_col && %(updated_at updated_on).include?(col.name)
- self.connection.add_column versioned_table_name, col.name, col.type,
- :limit => col.limit,
- :default => col.default,
- :scale => col.scale,
- :precision => col.precision
- end
-
- if type_col = self.columns_hash[inheritance_column]
- self.connection.add_column versioned_table_name, versioned_inheritance_column, type_col.type,
- :limit => type_col.limit,
- :default => type_col.default,
- :scale => type_col.scale,
- :precision => type_col.precision
- end
-
- if updated_col.nil?
- self.connection.add_column versioned_table_name, :updated_at, :timestamp
- end
- end
-
- # Rake migration task to drop the versioned table
- def drop_versioned_table
- self.connection.drop_table versioned_table_name
- end
-
- # Executes the block with the versioning callbacks disabled.
- #
- # Foo.without_revision do
- # @foo.save
- # end
- #
- def without_revision(&block)
- class_eval do
- CALLBACKS.each do |attr_name|
- alias_method "orig_#{attr_name}".to_sym, attr_name
- alias_method attr_name, :empty_callback
- end
- end
- block.call
- ensure
- class_eval do
- CALLBACKS.each do |attr_name|
- alias_method attr_name, "orig_#{attr_name}".to_sym
- end
- end
- end
-
- # Turns off optimistic locking for the duration of the block
- #
- # Foo.without_locking do
- # @foo.save
- # end
- #
- def without_locking(&block)
- current = ActiveRecord::Base.lock_optimistically
- ActiveRecord::Base.lock_optimistically = false if current
- result = block.call
- ActiveRecord::Base.lock_optimistically = true if current
- result
- end
- end
- end
- end
- end
- end
-
- ActiveRecord::Base.send :include, ActiveRecord::Acts::Versioned
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