Merge commit 'mainstream/master'

11 files changed, 319 insertions, 26 deletions

diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index 369c7fed33..4ed7b0889d 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -1,17 +1,5 @@
-$LOAD_PATH << File.join(File.dirname(__FILE__), '..', '..', 'activesupport', 'lib')
-
-# premature optimization?
-require 'active_support/inflector'
-require 'active_support/core_ext/string/inflections'
-String.send :include, ActiveSupport::CoreExtensions::String::Inflections
-
-require 'active_model/base'
 require 'active_model/observing'
-require 'active_model/callbacks'
-require 'active_model/validations'
-
-ActiveModel::Base.class_eval do
-  include ActiveModel::Observing
-  include ActiveModel::Callbacks
-  include ActiveModel::Validations
-end
\ No newline at end of file
+# disabled until they're tested
+# require 'active_model/callbacks'
+# require 'active_model/validations'
+require 'active_model/base'
\ No newline at end of file
diff --git a/activemodel/lib/active_model/base.rb b/activemodel/lib/active_model/base.rb
index 1141156da4..a500adfdf1 100644
--- a/activemodel/lib/active_model/base.rb
+++ b/activemodel/lib/active_model/base.rb
@@ -1,4 +1,8 @@
 module ActiveModel
   class Base
+    include Observing
+    # disabled, until they're tested
+    # include Callbacks
+    # include Validations
   end
 end
\ No newline at end of file
diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb
index 0114fc386b..c94f76109f 100644
--- a/activemodel/lib/active_model/callbacks.rb
+++ b/activemodel/lib/active_model/callbacks.rb
@@ -1,3 +1,5 @@
+require 'active_model/core'
+
 module ActiveModel
   module Callbacks
     
diff --git a/activemodel/lib/active_model/core.rb b/activemodel/lib/active_model/core.rb
new file mode 100644
index 0000000000..47b968e121
--- /dev/null
+++ b/activemodel/lib/active_model/core.rb
@@ -0,0 +1,7 @@
+# This file is required by each major ActiveModel component for the core requirements.  This allows you to
+# load individual pieces of ActiveModel as needed.
+$LOAD_PATH << File.join(File.dirname(__FILE__), '..', '..', '..', 'activesupport', 'lib')
+
+# premature optimization?
+# So far, we only need the string inflections and not the rest of ActiveSupport.
+require 'active_support/inflector'
\ No newline at end of file
diff --git a/activemodel/lib/active_model/observing.rb b/activemodel/lib/active_model/observing.rb
index db758f5185..9e99d7472c 100644
--- a/activemodel/lib/active_model/observing.rb
+++ b/activemodel/lib/active_model/observing.rb
@@ -1,4 +1,6 @@
 require 'observer'
+require 'singleton'
+require 'active_model/core'
 
 module ActiveModel
   module Observing
@@ -73,7 +75,7 @@ module ActiveModel
     # Start observing the declared classes and their subclasses.
     def initialize
       self.observed_classes = self.class.models if self.class.models
-      observed_classes.each { |klass| add_observer! klass }
+      observed_classes.each { |klass| klass.add_observer(self) }
     end
 
     # Send observed_method(object) if the method exists.
@@ -85,16 +87,12 @@ module ActiveModel
     # Passes the new subclass.
     def observed_class_inherited(subclass) #:nodoc:
       self.class.observe(observed_classes + [subclass])
-      add_observer!(subclass)
+      subclass.add_observer(self)
     end
 
-    protected
-      def observed_classes
-        @observed_classes ||= [self.class.observed_class]
-      end
-
-      def add_observer!(klass)
-        klass.add_observer(self)
-      end
+  protected
+    def observed_classes
+      @observed_classes ||= [self.class.observed_class]
+    end
   end
 end
\ No newline at end of file
diff --git a/activemodel/lib/active_model/state_machine.rb b/activemodel/lib/active_model/state_machine.rb
new file mode 100644
index 0000000000..96df6539ae
--- /dev/null
+++ b/activemodel/lib/active_model/state_machine.rb
@@ -0,0 +1,66 @@
+Dir[File.dirname(__FILE__) + "/state_machine/*.rb"].sort.each do |path|
+  filename = File.basename(path)
+  require "active_model/state_machine/#{filename}"
+end
+
+module ActiveModel
+  module StateMachine
+    class InvalidTransition < Exception
+    end
+
+    def self.included(base)
+      base.extend ClassMethods
+    end
+
+    module ClassMethods
+      def inherited(klass)
+        super
+        klass.state_machines = state_machines
+      end
+
+      def state_machines
+        @state_machines ||= {}
+      end
+
+      def state_machines=(value)
+        @state_machines = value ? value.dup : nil
+      end
+
+      def state_machine(name = nil, options = {}, &block)
+        if name.is_a?(Hash)
+          options = name
+          name    = nil
+        end
+        name ||= :default
+        state_machines[name] ||= Machine.new(self, name)
+        block ? state_machines[name].update(options, &block) : state_machines[name]
+      end
+    end
+
+    def current_state(name = nil, new_state = nil, persist = false)
+      sm   = self.class.state_machine(name)
+      ivar = sm.current_state_variable
+      if name && new_state
+        if persist && respond_to?(:write_state)
+          write_state(sm, new_state)
+        end
+
+        if respond_to?(:write_state_without_persistence)
+          write_state_without_persistence(sm, new_state)
+        end
+
+        instance_variable_set(ivar, new_state)
+      else
+        instance_variable_set(ivar, nil) unless instance_variable_defined?(ivar)
+        value = instance_variable_get(ivar)
+        return value if value
+
+        if respond_to?(:read_state)
+          value = instance_variable_set(ivar, read_state(sm))
+        end
+
+        value || sm.initial_state
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activemodel/lib/active_model/state_machine/event.rb b/activemodel/lib/active_model/state_machine/event.rb
new file mode 100644
index 0000000000..e8bc8ebdb7
--- /dev/null
+++ b/activemodel/lib/active_model/state_machine/event.rb
@@ -0,0 +1,62 @@
+module ActiveModel
+  module StateMachine
+    class Event
+      attr_reader :name, :success
+      
+      def initialize(machine, name, options = {}, &block)
+        @machine, @name, @transitions = machine, name, []
+        if machine
+          machine.klass.send(:define_method, "#{name.to_s}!") do |*args|
+            machine.fire_event(name, self, true, *args)
+          end
+
+          machine.klass.send(:define_method, "#{name.to_s}") do |*args|
+            machine.fire_event(name, self, false, *args)
+          end
+        end
+        update(options, &block)
+      end
+
+      def fire(obj, to_state = nil, *args)
+        transitions = @transitions.select { |t| t.from == obj.current_state(@machine ? @machine.name : nil) }
+        raise InvalidTransition if transitions.size == 0
+
+        next_state = nil
+        transitions.each do |transition|
+          next if to_state && !Array(transition.to).include?(to_state)
+          if transition.perform(obj)
+            next_state = to_state || Array(transition.to).first
+            transition.execute(obj, *args)
+            break
+          end
+        end
+        next_state
+      end
+
+      def transitions_from_state?(state)
+        @transitions.any? { |t| t.from? state }
+      end
+
+      def ==(event)
+        if event.is_a? Symbol
+          name == event
+        else
+          name == event.name
+        end
+      end
+
+      def update(options = {}, &block)
+        if options.key?(:success) then @success = options[:success] end
+        if block                  then instance_eval(&block)        end
+        self
+      end
+
+    private
+      def transitions(trans_opts)
+        Array(trans_opts[:from]).each do |s|
+          @transitions << StateTransition.new(trans_opts.merge({:from => s.to_sym}))
+        end
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/state_machine/machine.rb b/activemodel/lib/active_model/state_machine/machine.rb
new file mode 100644
index 0000000000..170505c0b2
--- /dev/null
+++ b/activemodel/lib/active_model/state_machine/machine.rb
@@ -0,0 +1,74 @@
+module ActiveModel
+  module StateMachine
+    class Machine
+      attr_accessor :initial_state, :states, :events, :state_index
+      attr_reader :klass, :name
+
+      def initialize(klass, name, options = {}, &block)
+        @klass, @name, @states, @state_index, @events = klass, name, [], {}, {}
+        update(options, &block)
+      end
+
+      def initial_state
+        @initial_state ||= (states.first ? states.first.name : nil)
+      end
+
+      def update(options = {}, &block)
+        if options.key?(:initial) then @initial_state = options[:initial] end
+        if block                  then instance_eval(&block)              end
+        self
+      end
+
+      def fire_event(event, record, persist, *args)
+        state_index[record.current_state(@name)].call_action(:exit, record)
+        if new_state = @events[event].fire(record, *args)
+          state_index[new_state].call_action(:enter, record)
+
+          if record.respond_to?(event_fired_callback)
+            record.send(event_fired_callback, record.current_state, new_state)
+          end
+
+          record.current_state(@name, new_state, persist)
+          record.send(@events[event].success) if @events[event].success
+          true
+        else
+          if record.respond_to?(event_failed_callback)
+            record.send(event_failed_callback, event)
+          end
+
+          false
+        end
+      end
+
+      def states_for_select
+        states.map { |st| [st.display_name, st.name.to_s] }
+      end
+
+      def events_for(state)
+        events = @events.values.select { |event| event.transitions_from_state?(state) }
+        events.map! { |event| event.name }
+      end
+
+      def current_state_variable
+        "@#{@name}_current_state"
+      end
+
+    private
+      def state(name, options = {})
+        @states << (state_index[name] ||= State.new(name, :machine => self)).update(options)
+      end
+
+      def event(name, options = {}, &block)
+        (@events[name] ||= Event.new(self, name)).update(options, &block)
+      end
+
+      def event_fired_callback
+        @event_fired_callback ||= (@name == :default ? '' : "#{@name}_") + 'event_fired'
+      end
+
+      def event_failed_callback
+        @event_failed_callback ||= (@name == :default ? '' : "#{@name}_") + 'event_failed'
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activemodel/lib/active_model/state_machine/state.rb b/activemodel/lib/active_model/state_machine/state.rb
new file mode 100644
index 0000000000..68eb2aa34a
--- /dev/null
+++ b/activemodel/lib/active_model/state_machine/state.rb
@@ -0,0 +1,50 @@
+module ActiveModel
+  module StateMachine
+    class State
+      attr_reader :name, :options
+
+      def initialize(name, options = {})
+        @name = name
+        machine = options.delete(:machine)
+        if machine
+          machine.klass.send(:define_method, "#{name}?") do
+            current_state.to_s == name.to_s
+          end
+        end
+        update(options)
+      end
+
+      def ==(state)
+        if state.is_a? Symbol
+          name == state
+        else
+          name == state.name
+        end
+      end
+
+      def call_action(action, record)
+        action = @options[action]
+        case action
+        when Symbol, String
+          record.send(action)
+        when Proc
+          action.call(record)
+        end
+      end
+
+      def display_name
+        @display_name ||= name.to_s.gsub(/_/, ' ').capitalize
+      end
+
+      def for_select
+        [display_name, name.to_s]
+      end
+
+      def update(options = {})
+        if options.key?(:display) then @display_name = options.delete(:display) end
+        @options = options
+        self
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/state_machine/state_transition.rb b/activemodel/lib/active_model/state_machine/state_transition.rb
new file mode 100644
index 0000000000..f9df998ea4
--- /dev/null
+++ b/activemodel/lib/active_model/state_machine/state_transition.rb
@@ -0,0 +1,40 @@
+module ActiveModel
+  module StateMachine
+    class StateTransition
+      attr_reader :from, :to, :options
+
+      def initialize(opts)
+        @from, @to, @guard, @on_transition = opts[:from], opts[:to], opts[:guard], opts[:on_transition]
+        @options = opts
+      end
+
+      def perform(obj)
+        case @guard
+        when Symbol, String
+          obj.send(@guard)
+        when Proc
+          @guard.call(obj)
+        else
+          true
+        end
+      end
+      
+      def execute(obj, *args)
+        case @on_transition
+        when Symbol, String
+          obj.send(@on_transition, *args)
+        when Proc
+          @on_transition.call(obj, *args)
+        end
+      end
+
+      def ==(obj)
+        @from == obj.from && @to == obj.to
+      end
+
+      def from?(value)
+        @from == value
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 34ef3b8f6e..7efe9901ca 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -1,3 +1,5 @@
+require 'active_model/core'
+
 module ActiveModel
   module Validations
     def self.included(base) # :nodoc: