initial statemachine machine and state classes

1 files changed, 43 insertions, 0 deletions

diff --git a/activemodel/lib/active_model/state_machine.rb b/activemodel/lib/active_model/state_machine.rb
new file mode 100644
index 0000000000..bb038f6b7a
--- /dev/null
+++ b/activemodel/lib/active_model/state_machine.rb
@@ -0,0 +1,43 @@
+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
+    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)
+      sm   = self.class.state_machine(name)
+      ivar = "@#{sm.name}_current_state"
+      instance_variable_get(ivar) || instance_variable_set(ivar, sm.initial_state)
+    end
+  end
+end
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