Merge pull request #1 from lyfeyaj/has-many-associations

add has many associations functionality

.gitignore

@@ -14,3 +14,5 @@ Gemfile.lock
 vendor/*
 .idea
 .rvmrc
+.tags
+.tags_sorted_by_file

README.md

@@ -1,4 +1,4 @@
-# PaperTrail [![Build Status](https://img.shields.io/travis/airblade/paper_trail.svg)](https://travis-ci.org/airblade/paper_trail) [![Dependency Status](https://img.shields.io/gemnasium/airblade/paper_trail.svg)](https://gemnasium.com/airblade/paper_trail)
+# PaperTrail [![Build Status](https://img.shields.io/travis/airblade/paper_trail/master.svg)](https://travis-ci.org/airblade/paper_trail) [![Dependency Status](https://img.shields.io/gemnasium/airblade/paper_trail.svg)](https://gemnasium.com/airblade/paper_trail)
 
 PaperTrail lets you track changes to your models' data.  It's good for auditing or versioning.  You can see how a model looked at any stage in its lifecycle, revert it to any version, and even undelete it after it's been destroyed.
 

lib/generators/paper_trail/install_generator.rb

@@ -12,12 +12,23 @@ class InstallGenerator < ::Rails::Generators::Base
     desc 'Generates (but does not run) a migration to add a versions table.'
 
     def create_migration_file
-      migration_template 'create_versions.rb', 'db/migrate/create_versions.rb'
-      migration_template 'add_object_changes_column_to_versions.rb', 'db/migrate/add_object_changes_column_to_versions.rb' if options.with_changes?
+      add_paper_trail_migration('create_versions')
+      add_paper_trail_migration('add_object_changes_column_to_versions') if options.with_changes?
+      add_paper_trail_migration('create_version_associations')
+      add_paper_trail_migration('add_transaction_id_column_to_versions')
     end
 
     def self.next_migration_number(dirname)
       ::ActiveRecord::Generators::Base.next_migration_number(dirname)
     end
+
+    protected
+    def add_paper_trail_migration(template)
+      migration_dir = File.expand_path('db/migrate')
+
+      if !self.class.migration_exists?(migration_dir, template)
+        migration_template "#{template}.rb", "db/migrate/#{template}.rb"
+      end
+    end
   end
 end

lib/generators/paper_trail/templates/add_transaction_id_column_to_versions.rb

@@ -0,0 +1,11 @@
+class AddTransactionIdColumnToVersions < ActiveRecord::Migration
+  def self.up
+    add_column :versions, :transaction_id, :integer
+    add_index :versions, [:transaction_id]
+  end
+
+  def self.down
+    remove_column :versions, :transaction_id
+    remove_index :versions, [:transaction_id]
+  end
+end

lib/generators/paper_trail/templates/create_version_associations.rb

@@ -0,0 +1,17 @@
+class CreateVersionAssociations < ActiveRecord::Migration
+  def self.up
+    create_table :version_associations do |t|
+      t.integer  :version_id
+      t.string   :foreign_key_name, :null => false
+      t.integer  :foreign_key_id
+    end
+    add_index :version_associations, [:version_id]
+    add_index :version_associations, [:foreign_key_name, :foreign_key_id], :name => 'index_on_foreign_key_name_and foreign_key_id'
+  end
+
+  def self.down
+    remove_index :version_associations, [:version_id]
+    remove_index :version_associations, [:foreign_key_name, :foreign_key_id], :name => 'index_on_foreign_key_name_and foreign_key_id'
+    drop_table :version_associations
+  end
+end

lib/paper_trail.rb

@@ -92,6 +92,28 @@ def self.active_record_protected_attributes?
     @active_record_protected_attributes ||= ::ActiveRecord::VERSION::MAJOR < 4 || !!defined?(ProtectedAttributes)
   end
 
+  def self.transaction?
+    ActiveRecord::Base.connection.open_transactions > 0 || paper_trail_store[:transaction_open]
+  end
+
+  def self.start_transaction
+    paper_trail_store[:transaction_open] = true
+    self.transaction_id = nil
+  end
+
+  def self.end_transaction
+    paper_trail_store[:transaction_open] = false
+    self.transaction_id = nil
+  end
+
+  def self.transaction_id
+    paper_trail_store[:transaction_id]
+  end
+
+  def self.transaction_id=(id)
+    paper_trail_store[:transaction_id] = id
+  end
+
   private
 
   # Thread-safe hash to hold PaperTrail's data.
@@ -119,6 +141,7 @@ def self.configure
 end
 
 require 'paper_trail/version'
+require 'paper_trail/version_association'
 
 # Require frameworks
 require 'paper_trail/frameworks/rails'

lib/paper_trail/has_paper_trail.rb

@@ -14,11 +14,11 @@ module ClassMethods
       #               `:create`, `:update`, `:destroy` as desired.
       # :class_name   the name of a custom Version class.  This class should inherit from `PaperTrail::Version`.
       # :ignore       an array of attributes for which a new `Version` will not be created if only they change.
-      #               it can also aceept a Hash as an argument where the key is the attribute to ignore (a `String` or `Symbol`), 
+      #               it can also aceept a Hash as an argument where the key is the attribute to ignore (a `String` or `Symbol`),
       #               which will only be ignored if the value is a `Proc` which returns truthily.
       # :if, :unless  Procs that allow to specify conditions when to save versions for an object
       # :only         inverse of `ignore` - a new `Version` will be created only for these attributes if supplied
-      #               it can also aceept a Hash as an argument where the key is the attribute to track (a `String` or `Symbol`), 
+      #               it can also aceept a Hash as an argument where the key is the attribute to track (a `String` or `Symbol`),
       #               which will only be counted if the value is a `Proc` which returns truthily.
       # :skip         fields to ignore completely.  As with `ignore`, updates to these fields will not create
       #               a new `Version`.  In addition, these fields will not be included in the serialized versions
@@ -74,6 +74,10 @@ def has_paper_trail(options = {})
         after_create  :record_create, :if => :save_version? if options_on.empty? || options_on.include?(:create)
         before_update :record_update, :if => :save_version? if options_on.empty? || options_on.include?(:update)
         after_destroy :record_destroy, :if => :save_version? if options_on.empty? || options_on.include?(:destroy)
+
+        # Reset the transaction id when the transaction is closed
+        after_commit :reset_transaction_id
+        after_rollback :reset_transaction_id
       end
 
       # Switches PaperTrail off for this class.
@@ -91,7 +95,7 @@ def paper_trail_on!
         PaperTrail.enabled_for_model(self, true)
       end
 
-	    def paper_trail_on
+      def paper_trail_on
         warn "DEPRECATED: use `paper_trail_on!` instead of `paper_trail_on`. Support for `paper_trail_on` will be removed in PaperTrail 3.1"
         self.paper_trail_on!
       end
@@ -216,6 +220,16 @@ def without_versioning(method = nil)
         self.class.paper_trail_on! if paper_trail_was_enabled
       end
 
+      # Utility method for reifying. Anything executed inside the block will appear like a new record
+      def appear_as_new_record
+        instance_eval {
+          alias :old_new_record? :new_record?
+          alias :new_record? :present?
+        }
+        yield
+        instance_eval { alias :new_record? :old_new_record? }
+      end
+
       # Mimicks behavior of `touch` method from `ActiveRecord::Persistence`, but generates a version
       #
       # TODO: lookinto leveraging the `after_touch` callback from `ActiveRecord` to allow the
@@ -241,31 +255,37 @@ def source_version
       def record_create
         if paper_trail_switched_on?
           data = {
-            :event     => paper_trail_event || 'create',
-            :whodunnit => PaperTrail.whodunnit
+            :event          => paper_trail_event || 'create',
+            :whodunnit      => PaperTrail.whodunnit,
+            :transaction_id => PaperTrail.transaction_id
           }
 
           if changed_notably? and self.class.paper_trail_version_class.column_names.include?('object_changes')
             data[:object_changes] = self.class.paper_trail_version_class.object_changes_col_is_json? ? changes_for_paper_trail :
               PaperTrail.serializer.dump(changes_for_paper_trail)
           end
-          send(self.class.versions_association_name).create! merge_metadata(data)
+          version = send(self.class.versions_association_name).create! merge_metadata(data)
+          set_transaction_id(version)
+          save_associations(version)
         end
       end
 
       def record_update
         if paper_trail_switched_on? && changed_notably?
           object_attrs = object_attrs_for_paper_trail(item_before_change)
           data = {
-            :event     => paper_trail_event || 'update',
-            :object    => self.class.paper_trail_version_class.object_col_is_json? ? object_attrs : PaperTrail.serializer.dump(object_attrs),
-            :whodunnit => PaperTrail.whodunnit
+            :event          => paper_trail_event || 'update',
+            :object         => self.class.paper_trail_version_class.object_col_is_json? ? object_attrs : PaperTrail.serializer.dump(object_attrs),
+            :whodunnit      => PaperTrail.whodunnit,
+            :transaction_id => PaperTrail.transaction_id
           }
           if self.class.paper_trail_version_class.column_names.include?('object_changes')
             data[:object_changes] = self.class.paper_trail_version_class.object_changes_col_is_json? ? changes_for_paper_trail :
               PaperTrail.serializer.dump(changes_for_paper_trail)
           end
-          send(self.class.versions_association_name).build merge_metadata(data)
+          version = send(self.class.versions_association_name).create merge_metadata(data)
+          set_transaction_id(version)
+          save_associations(version)
         end
       end
 
@@ -279,17 +299,42 @@ def record_destroy
         if paper_trail_switched_on? and not new_record?
           object_attrs = object_attrs_for_paper_trail(item_before_change)
           data = {
-            :item_id   => self.id,
-            :item_type => self.class.base_class.name,
-            :event     => paper_trail_event || 'destroy',
-            :object    => self.class.paper_trail_version_class.object_col_is_json? ? object_attrs : PaperTrail.serializer.dump(object_attrs),
-            :whodunnit => PaperTrail.whodunnit
+            :item_id        => self.id,
+            :item_type      => self.class.base_class.name,
+            :event          => paper_trail_event || 'destroy',
+            :object         => self.class.paper_trail_version_class.object_col_is_json? ? object_attrs : PaperTrail.serializer.dump(object_attrs),
+            :whodunnit      => PaperTrail.whodunnit,
+            :transaction_id => PaperTrail.transaction_id
           }
-          self.class.paper_trail_version_class.create merge_metadata(data)
+          version = self.class.paper_trail_version_class.create merge_metadata(data)
           send(self.class.versions_association_name).send :load_target
+          set_transaction_id(version)
+          save_associations(version)
+        end
+      end
+
+      def save_associations(version)
+        self.class.reflect_on_all_associations(:belongs_to).each do |assoc|
+          PaperTrail::VersionAssociation.create(
+            :version_id => version.id,
+            :foreign_key_name => assoc.foreign_key,
+            :foreign_key_id => self.send(assoc.foreign_key)
+          )
         end
       end
 
+      def set_transaction_id(version)
+        if PaperTrail.transaction? && PaperTrail.transaction_id.nil?
+           PaperTrail.transaction_id = version.id
+           version.transaction_id = version.id
+           version.save
+        end
+      end
+
+      def reset_transaction_id
+        PaperTrail.transaction_id = nil
+      end
+
       def merge_metadata(data)
         # First we merge the model-level metadata in `meta`.
         paper_trail_options[:meta].each do |k,v|

lib/paper_trail/version_association.rb

@@ -0,0 +1,7 @@
+module PaperTrail
+  class VersionAssociation < ActiveRecord::Base
+    belongs_to :version
+
+    attr_accessible :version_id, :foreign_key_name, :foreign_key_id if PaperTrail.active_record_protected_attributes?
+  end
+end