564 lines
23 KiB
Ruby
564 lines
23 KiB
Ruby
# Copyright (c) 2005 Rick Olson
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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module ActiveRecord #:nodoc:
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module Acts #:nodoc:
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# Specify this act if you want to save a copy of the row in a versioned table. This assumes there is a
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# versioned table ready and that your model has a version field. This works with optimistic locking if the lock_version
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# column is present as well.
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#
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# 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
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# your container for the changes to be reflected. In development mode this usually means restarting WEBrick.
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#
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# class Page < ActiveRecord::Base
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# # assumes pages_versions table
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# acts_as_versioned
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# end
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#
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# Example:
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#
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# page = Page.create(:title => 'hello world!')
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# page.version # => 1
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#
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# page.title = 'hello world'
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# page.save
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# page.version # => 2
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# page.versions.size # => 2
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#
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# page.revert_to(1) # using version number
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# page.title # => 'hello world!'
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#
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# page.revert_to(page.versions.last) # using versioned instance
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# page.title # => 'hello world'
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#
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# page.versions.earliest # efficient query to find the first version
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# page.versions.latest # efficient query to find the most recently created version
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#
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#
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# Simple Queries to page between versions
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#
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# page.versions.before(version)
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# page.versions.after(version)
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#
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# Access the previous/next versions from the versioned model itself
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#
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# version = page.versions.latest
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# version.previous # go back one version
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# version.next # go forward one version
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#
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# See ActiveRecord::Acts::Versioned::ClassMethods#acts_as_versioned for configuration options
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module Versioned
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CALLBACKS = [:set_new_version, :save_version_on_create, :save_version?, :clear_altered_attributes]
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def self.included(base) # :nodoc:
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base.extend ClassMethods
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end
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module ClassMethods
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# == Configuration options
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#
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# * <tt>class_name</tt> - versioned model class name (default: PageVersion in the above example)
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# * <tt>table_name</tt> - versioned model table name (default: page_versions in the above example)
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# * <tt>foreign_key</tt> - foreign key used to relate the versioned model to the original model (default: page_id in the above example)
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# * <tt>inheritance_column</tt> - name of the column to save the model's inheritance_column value for STI. (default: versioned_type)
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# * <tt>version_column</tt> - name of the column in the model that keeps the version number (default: version)
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# * <tt>sequence_name</tt> - name of the custom sequence to be used by the versioned model.
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# * <tt>limit</tt> - number of revisions to keep, defaults to unlimited
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# * <tt>if</tt> - symbol of method to check before saving a new version. If this method returns false, a new version is not saved.
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# For finer control, pass either a Proc or modify Model#version_condition_met?
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#
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# acts_as_versioned :if => Proc.new { |auction| !auction.expired? }
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#
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# or...
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#
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# class Auction
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# def version_condition_met? # totally bypasses the <tt>:if</tt> option
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# !expired?
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# end
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# end
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#
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# * <tt>if_changed</tt> - Simple way of specifying attributes that are required to be changed before saving a model. This takes
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# either a symbol or array of symbols. WARNING - This will attempt to overwrite any attribute setters you may have.
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# Use this instead if you want to write your own attribute setters (and ignore if_changed):
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#
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# def name=(new_name)
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# write_changed_attribute :name, new_name
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# end
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#
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# * <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
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# to create an anonymous mixin:
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#
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# class Auction
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# acts_as_versioned do
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# def started?
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# !started_at.nil?
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# end
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# end
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# end
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#
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# or...
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#
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# module AuctionExtension
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# def started?
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# !started_at.nil?
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# end
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# end
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# class Auction
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# acts_as_versioned :extend => AuctionExtension
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# end
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#
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# Example code:
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#
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# @auction = Auction.find(1)
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# @auction.started?
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# @auction.versions.first.started?
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#
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# == Database Schema
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#
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# The model that you're versioning needs to have a 'version' attribute. The model is versioned
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# into a table called #{model}_versions where the model name is singlular. The _versions table should
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# contain all the fields you want versioned, the same version column, and a #{model}_id foreign key field.
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#
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# A lock_version field is also accepted if your model uses Optimistic Locking. If your table uses Single Table inheritance,
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# then that field is reflected in the versioned model as 'versioned_type' by default.
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#
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# Acts_as_versioned comes prepared with the ActiveRecord::Acts::Versioned::ActMethods::ClassMethods#create_versioned_table
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# method, perfect for a migration. It will also create the version column if the main model does not already have it.
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#
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# class AddVersions < ActiveRecord::Migration
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# def self.up
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# # create_versioned_table takes the same options hash
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# # that create_table does
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# Post.create_versioned_table
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# end
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#
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# def self.down
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# Post.drop_versioned_table
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# end
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# end
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#
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# == Changing What Fields Are Versioned
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#
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# By default, acts_as_versioned will version all but these fields:
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#
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# [self.primary_key, inheritance_column, 'version', 'lock_version', versioned_inheritance_column]
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#
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# You can add or change those by modifying #non_versioned_columns. Note that this takes strings and not symbols.
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#
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# class Post < ActiveRecord::Base
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# acts_as_versioned
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# self.non_versioned_columns << 'comments_count'
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# end
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#
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def acts_as_versioned(options = {}, &extension)
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# don't allow multiple calls
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return if self.included_modules.include?(ActiveRecord::Acts::Versioned::ActMethods)
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send :include, ActiveRecord::Acts::Versioned::ActMethods
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cattr_accessor :versioned_class_name, :versioned_foreign_key, :versioned_table_name, :versioned_inheritance_column,
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:version_column, :max_version_limit, :track_altered_attributes, :version_condition, :version_sequence_name, :non_versioned_columns,
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:version_association_options
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# legacy
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alias_method :non_versioned_fields, :non_versioned_columns
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alias_method :non_versioned_fields=, :non_versioned_columns=
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class << self
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alias_method :non_versioned_fields, :non_versioned_columns
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alias_method :non_versioned_fields=, :non_versioned_columns=
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end
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send :attr_accessor, :altered_attributes
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self.versioned_class_name = options[:class_name] || "Version"
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self.versioned_foreign_key = options[:foreign_key] || self.to_s.foreign_key
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self.versioned_table_name = options[:table_name] || "#{table_name_prefix}#{base_class.name.demodulize.underscore}_versions#{table_name_suffix}"
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self.versioned_inheritance_column = options[:inheritance_column] || "versioned_#{inheritance_column}"
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self.version_column = options[:version_column] || 'version'
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self.version_sequence_name = options[:sequence_name]
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self.max_version_limit = options[:limit].to_i
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self.version_condition = options[:if] || true
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self.non_versioned_columns = [self.primary_key, inheritance_column, 'version', 'lock_version', versioned_inheritance_column]
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self.version_association_options = {
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:class_name => "#{self.to_s}::#{versioned_class_name}",
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:foreign_key => versioned_foreign_key,
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:dependent => :delete_all
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}.merge(options[:association_options] || {})
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if block_given?
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extension_module_name = "#{versioned_class_name}Extension"
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silence_warnings do
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self.const_set(extension_module_name, Module.new(&extension))
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end
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options[:extend] = self.const_get(extension_module_name)
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end
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class_eval do
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has_many :versions, version_association_options do
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# finds earliest version of this record
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def earliest
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@earliest ||= find(:first, :order => 'version')
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end
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# find latest version of this record
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def latest
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@latest ||= find(:first, :order => 'version desc')
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end
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end
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before_save :set_new_version
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after_create :save_version_on_create
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after_update :save_version
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after_save :clear_old_versions
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after_save :clear_altered_attributes
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unless options[:if_changed].nil?
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self.track_altered_attributes = true
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options[:if_changed] = [options[:if_changed]] unless options[:if_changed].is_a?(Array)
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options[:if_changed].each do |attr_name|
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define_method("#{attr_name}=") do |value|
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write_changed_attribute attr_name, value
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end
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end
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end
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include options[:extend] if options[:extend].is_a?(Module)
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end
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# create the dynamic versioned model
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const_set(versioned_class_name, Class.new(ActiveRecord::Base)).class_eval do
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def self.reloadable? ; false ; end
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# find first version before the given version
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def self.before(version)
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find :first, :order => 'version desc',
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:conditions => ["#{original_class.versioned_foreign_key} = ? and version < ?", version.send(original_class.versioned_foreign_key), version.version]
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end
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# find first version after the given version.
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def self.after(version)
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find :first, :order => 'version',
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:conditions => ["#{original_class.versioned_foreign_key} = ? and version > ?", version.send(original_class.versioned_foreign_key), version.version]
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end
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def previous
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self.class.before(self)
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end
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def next
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self.class.after(self)
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end
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def versions_count
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page.version
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end
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end
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versioned_class.cattr_accessor :original_class
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versioned_class.original_class = self
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versioned_class.set_table_name versioned_table_name
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versioned_class.belongs_to self.to_s.demodulize.underscore.to_sym,
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:class_name => "::#{self.to_s}",
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:foreign_key => versioned_foreign_key
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versioned_class.send :include, options[:extend] if options[:extend].is_a?(Module)
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versioned_class.set_sequence_name version_sequence_name if version_sequence_name
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end
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end
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module ActMethods
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def self.included(base) # :nodoc:
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base.extend ClassMethods
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end
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# Finds a specific version of this record
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def find_version(version = nil)
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self.class.find_version(id, version)
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end
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# Saves a version of the model if applicable
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def save_version
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save_version_on_create if save_version?
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end
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# Saves a version of the model in the versioned table. This is called in the after_save callback by default
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def save_version_on_create
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rev = self.class.versioned_class.new
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self.clone_versioned_model(self, rev)
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rev.version = send(self.class.version_column)
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rev.send("#{self.class.versioned_foreign_key}=", self.id)
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rev.save
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end
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# Clears old revisions if a limit is set with the :limit option in <tt>acts_as_versioned</tt>.
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# Override this method to set your own criteria for clearing old versions.
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def clear_old_versions
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return if self.class.max_version_limit == 0
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excess_baggage = send(self.class.version_column).to_i - self.class.max_version_limit
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if excess_baggage > 0
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sql = "DELETE FROM #{self.class.versioned_table_name} WHERE version <= #{excess_baggage} AND #{self.class.versioned_foreign_key} = #{self.id}"
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self.class.versioned_class.connection.execute sql
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end
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end
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def versions_count
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version
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end
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# Reverts a model to a given version. Takes either a version number or an instance of the versioned model
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def revert_to(version)
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if version.is_a?(self.class.versioned_class)
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return false unless version.send(self.class.versioned_foreign_key) == self.id and !version.new_record?
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else
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return false unless version = versions.find_by_version(version)
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end
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self.clone_versioned_model(version, self)
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self.send("#{self.class.version_column}=", version.version)
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true
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end
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# Reverts a model to a given version and saves the model.
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# Takes either a version number or an instance of the versioned model
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def revert_to!(version)
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revert_to(version) ? save_without_revision : false
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end
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# Temporarily turns off Optimistic Locking while saving. Used when reverting so that a new version is not created.
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def save_without_revision
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save_without_revision!
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true
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rescue
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false
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end
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def save_without_revision!
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without_locking do
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without_revision do
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save!
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end
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end
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end
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# Returns an array of attribute keys that are versioned. See non_versioned_columns
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def versioned_attributes
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self.attributes.keys.select { |k| !self.class.non_versioned_columns.include?(k) }
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end
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# If called with no parameters, gets whether the current model has changed and needs to be versioned.
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# If called with a single parameter, gets whether the parameter has changed.
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def changed?(attr_name = nil)
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attr_name.nil? ?
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(!self.class.track_altered_attributes || (altered_attributes && altered_attributes.length > 0)) :
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(altered_attributes && altered_attributes.include?(attr_name.to_s))
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end
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# keep old dirty? method
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alias_method :dirty?, :changed?
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# Clones a model. Used when saving a new version or reverting a model's version.
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def clone_versioned_model(orig_model, new_model)
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self.versioned_attributes.each do |key|
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new_model.send("#{key}=", orig_model.send(key)) if orig_model.has_attribute?(key)
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end
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if orig_model.is_a?(self.class.versioned_class)
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new_model[new_model.class.inheritance_column] = orig_model[self.class.versioned_inheritance_column]
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elsif new_model.is_a?(self.class.versioned_class)
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new_model[self.class.versioned_inheritance_column] = orig_model[orig_model.class.inheritance_column]
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end
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end
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# Checks whether a new version shall be saved or not. Calls <tt>version_condition_met?</tt> and <tt>changed?</tt>.
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def save_version?
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version_condition_met? && changed?
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end
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# Checks condition set in the :if option to check whether a revision should be created or not. Override this for
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# custom version condition checking.
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def version_condition_met?
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case
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when version_condition.is_a?(Symbol)
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send(version_condition)
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when version_condition.respond_to?(:call) && (version_condition.arity == 1 || version_condition.arity == -1)
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version_condition.call(self)
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else
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version_condition
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end
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end
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# Executes the block with the versioning callbacks disabled.
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#
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# @foo.without_revision do
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# @foo.save
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# end
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#
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def without_revision(&block)
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self.class.without_revision(&block)
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end
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# Turns off optimistic locking for the duration of the block
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#
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# @foo.without_locking do
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# @foo.save
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# end
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#
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def without_locking(&block)
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self.class.without_locking(&block)
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end
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def empty_callback() end #:nodoc:
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protected
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# sets the new version before saving, unless you're using optimistic locking. In that case, let it take care of the version.
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def set_new_version
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self.send("#{self.class.version_column}=", self.next_version) if new_record? || (!locking_enabled? && save_version?)
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end
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# Gets the next available version for the current record, or 1 for a new record
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def next_version
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return 1 if new_record?
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(versions.calculate(:max, :version) || 0) + 1
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end
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# clears current changed attributes. Called after save.
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def clear_altered_attributes
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self.altered_attributes = []
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end
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def write_changed_attribute(attr_name, attr_value)
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# Convert to db type for comparison. Avoids failing Float<=>String comparisons.
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attr_value_for_db = self.class.columns_hash[attr_name.to_s].type_cast(attr_value)
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(self.altered_attributes ||= []) << attr_name.to_s unless self.changed?(attr_name) || self.send(attr_name) == attr_value_for_db
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write_attribute(attr_name, attr_value_for_db)
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end
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module ClassMethods
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# Finds a specific version of a specific row of this model
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def find_version(id, version = nil)
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return find(id) unless version
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conditions = ["#{versioned_foreign_key} = ? AND version = ?", id, version]
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options = { :conditions => conditions, :limit => 1 }
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if result = find_versions(id, options).first
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result
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else
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raise RecordNotFound, "Couldn't find #{name} with ID=#{id} and VERSION=#{version}"
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end
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end
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# Finds versions of a specific model. Takes an options hash like <tt>find</tt>
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def find_versions(id, options = {})
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versioned_class.find :all, {
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:conditions => ["#{versioned_foreign_key} = ?", id],
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:order => 'version' }.merge(options)
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end
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# Returns an array of columns that are versioned. See non_versioned_columns
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def versioned_columns
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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 |