Extract ActiveSupport::Callbacks from Active Record, test case setup and teardown, and ActionController::Dispatcher. Closes #10727.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8664 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

6 files changed, 201 insertions, 50 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index db46ce4f4d..5cd4a483e4 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Extract ActiveSupport::Callbacks from Active Record, test case setup and teardown, and ActionController::Dispatcher.  #10727 [Josh Peek]
+
 * Introducing DateTime #utc, #utc? and #utc_offset, for duck-typing compatibility with Time. Closes #10002 [Geoff Buesing]
 
 * Time#to_json uses Numeric#to_utc_offset_s to output a cross-platform-consistent representation without having to convert to DateTime. References #9750 [Geoff Buesing]
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index c4b7cc8cba..7a0476b729 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -26,6 +26,7 @@ $:.unshift(File.dirname(__FILE__))
 require 'active_support/vendor'
 require 'active_support/basic_object'
 require 'active_support/inflector'
+require 'active_support/callbacks'
 
 require 'active_support/core_ext'
 
diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
new file mode 100644
index 0000000000..ac9f1a9d5f
--- /dev/null
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -0,0 +1,94 @@
+module ActiveSupport
+  module Callbacks
+    class Callback
+      def self.run(callbacks, object, options = {}, &terminator)
+        enumerator  = options[:enumerator] || :each
+
+        unless block_given?
+          callbacks.send(enumerator) { |callback| callback.call(object) }
+        else
+          callbacks.send(enumerator) do |callback|
+            result = callback.call(object)
+            break result if terminator.call(result, object)
+          end
+        end
+      end
+
+      attr_reader :kind, :method, :identifier, :options
+
+      def initialize(kind, method, options = {})
+        @kind       = kind
+        @method     = method
+        @identifier = options[:identifier]
+        @options    = options
+      end
+
+      def call(object)
+        evaluate_method(method, object) if should_run_callback?(object)
+      end
+
+      private
+        def evaluate_method(method, object)
+          case method
+            when Symbol
+              object.send(method)
+            when String
+              eval(method, object.instance_eval { binding })
+            when Proc, Method
+              method.call(object)
+            else
+              if method.respond_to?(kind)
+                method.send(kind, object)
+              else
+                raise ArgumentError,
+                  "Callbacks must be a symbol denoting the method to call, a string to be evaluated, " +
+                  "a block to be invoked, or an object responding to the callback method."
+              end
+            end
+        end
+
+        def should_run_callback?(object)
+          if options[:if]
+            evaluate_method(options[:if], object)
+          elsif options[:unless]
+            !evaluate_method(options[:unless], object)
+          else
+            true
+          end
+        end
+    end
+
+    def self.included(base)
+      base.extend ClassMethods
+    end
+
+    module ClassMethods
+      def define_callbacks(*callbacks)
+        callbacks.each do |callback|
+          class_eval <<-"end_eval"
+            def self.#{callback}(*methods, &block)
+              options = methods.extract_options!
+              methods << block if block_given?
+              callbacks = methods.map { |method| Callback.new(:#{callback}, method, options) }
+              (@#{callback}_callbacks ||= []).concat callbacks
+            end
+
+            def self.#{callback}_callback_chain
+              @#{callback}_callbacks ||= []
+
+              if superclass.respond_to?(:#{callback}_callback_chain)
+                superclass.#{callback}_callback_chain + @#{callback}_callbacks
+              else
+                @#{callback}_callbacks
+              end
+            end
+          end_eval
+        end
+      end
+    end
+
+    def run_callbacks(kind, options = {}, &block)
+      Callback.run(self.class.send("#{kind}_callback_chain"), self, options, &block)
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/testing/setup_and_teardown.rb b/activesupport/lib/active_support/testing/setup_and_teardown.rb
index 1639462fae..b2a937edd0 100644
--- a/activesupport/lib/active_support/testing/setup_and_teardown.rb
+++ b/activesupport/lib/active_support/testing/setup_and_teardown.rb
@@ -2,7 +2,8 @@ module ActiveSupport
   module Testing
     module SetupAndTeardown
       def self.included(base)
-        base.extend ClassMethods
+        base.send :include, ActiveSupport::Callbacks
+        base.define_callbacks :setup, :teardown
 
         begin
           require 'mocha'
@@ -12,38 +13,6 @@ module ActiveSupport
         end
       end
 
-      module ClassMethods
-        def setup(*method_names, &block)
-          method_names << block if block_given?
-          (@setup_callbacks ||= []).concat method_names
-        end
-
-        def teardown(*method_names, &block)
-          method_names << block if block_given?
-          (@teardown_callbacks ||= []).concat method_names
-        end
-
-        def setup_callback_chain
-          @setup_callbacks ||= []
-
-          if superclass.respond_to?(:setup_callback_chain)
-            superclass.setup_callback_chain + @setup_callbacks
-          else
-            @setup_callbacks
-          end
-        end
-
-        def teardown_callback_chain
-          @teardown_callbacks ||= []
-
-          if superclass.respond_to?(:teardown_callback_chain)
-            superclass.teardown_callback_chain + @teardown_callbacks
-          else
-            @teardown_callbacks
-          end
-        end
-      end
-
       # This redefinition is unfortunate but test/unit shows us no alternative.
       def run_with_callbacks(result) #:nodoc:
         return if @method_name.to_s == "default_test"
@@ -63,7 +32,7 @@ module ActiveSupport
         ensure
           begin
             teardown
-            run_callbacks :teardown, :reverse_each
+            run_callbacks :teardown, :enumerator => :reverse_each
           rescue Test::Unit::AssertionFailedError => e
             add_failure(e.message, e.backtrace)
           rescue *Test::Unit::TestCase::PASSTHROUGH_EXCEPTIONS
@@ -98,7 +67,7 @@ module ActiveSupport
           ensure
             begin
               teardown
-              run_callbacks :teardown, :reverse_each
+              run_callbacks :teardown, :enumerator => :reverse_each
             rescue Test::Unit::AssertionFailedError => e
               add_failure(e.message, e.backtrace)
             rescue StandardError, ScriptError
@@ -111,17 +80,6 @@ module ActiveSupport
         result.add_run
         yield(Test::Unit::TestCase::FINISHED, name)
       end
-
-      protected
-        def run_callbacks(kind, enumerator = :each)
-          self.class.send("#{kind}_callback_chain").send(enumerator) do |callback|
-            case callback
-            when Proc; callback.call(self)
-            when String, Symbol; send!(callback)
-            else raise ArgumentError, "Unrecognized callback #{callback.inspect}"
-            end
-          end
-        end
     end
   end
 end
diff --git a/activesupport/test/callbacks_test.rb b/activesupport/test/callbacks_test.rb
new file mode 100644
index 0000000000..6d390bbc5c
--- /dev/null
+++ b/activesupport/test/callbacks_test.rb
@@ -0,0 +1,96 @@
+require 'abstract_unit'
+
+class Record
+  include ActiveSupport::Callbacks
+
+  define_callbacks :before_save, :after_save
+
+  class << self
+    def callback_symbol(callback_method)
+      returning("#{callback_method}_method") do |method_name|
+        define_method(method_name) do
+          history << [callback_method, :symbol]
+        end
+      end
+    end
+
+    def callback_string(callback_method)
+      "history << [#{callback_method.to_sym.inspect}, :string]"
+    end
+
+    def callback_proc(callback_method)
+      Proc.new { |model| model.history << [callback_method, :proc] }
+    end
+
+    def callback_object(callback_method)
+      klass = Class.new
+      klass.send(:define_method, callback_method) do |model|
+        model.history << [callback_method, :object]
+      end
+      klass.new
+    end
+  end
+
+  def history
+    @history ||= []
+  end
+end
+
+class Person < Record
+  [:before_save, :after_save].each do |callback_method|
+    callback_method_sym = callback_method.to_sym
+    send(callback_method, callback_symbol(callback_method_sym))
+    send(callback_method, callback_string(callback_method_sym))
+    send(callback_method, callback_proc(callback_method_sym))
+    send(callback_method, callback_object(callback_method_sym))
+    send(callback_method) { |model| model.history << [callback_method_sym, :block] }
+  end
+
+  def save
+    run_callbacks(:before_save)
+    run_callbacks(:after_save)
+  end
+end
+
+class ConditionalPerson < Record
+  before_save Proc.new { |r| r.history << [:before_save, :proc] }, :if => Proc.new { |r| true }
+  before_save Proc.new { |r| r.history << "b00m" }, :if => Proc.new { |r| false }
+  before_save Proc.new { |r| r.history << [:before_save, :proc] }, :unless => Proc.new { |r| false }
+  before_save Proc.new { |r| r.history << "b00m" }, :unless => Proc.new { |r| true }
+
+  def save
+    run_callbacks(:before_save)
+    run_callbacks(:after_save)
+  end
+end
+
+class CallbacksTest < Test::Unit::TestCase
+  def test_save_person
+    person = Person.new
+    assert_equal [], person.history
+    person.save
+    assert_equal [
+      [:before_save, :symbol],
+      [:before_save, :string],
+      [:before_save, :proc],
+      [:before_save, :object],
+      [:before_save, :block],
+      [:after_save, :symbol],
+      [:after_save, :string],
+      [:after_save, :proc],
+      [:after_save, :object],
+      [:after_save, :block]
+    ], person.history
+  end
+end
+
+class ConditionalCallbackTest < Test::Unit::TestCase
+  def test_save_conditional_person
+    person = ConditionalPerson.new
+    person.save
+    assert_equal [
+      [:before_save, :proc],
+      [:before_save, :proc]
+    ], person.history
+  end
+end
diff --git a/activesupport/test/test_test.rb b/activesupport/test/test_test.rb
index 88b505e59c..1e75e18602 100644
--- a/activesupport/test/test_test.rb
+++ b/activesupport/test/test_test.rb
@@ -79,9 +79,9 @@ class SetupAndTeardownTest < Test::Unit::TestCase
   teardown :foo, :sentinel, :foo
 
   def test_inherited_setup_callbacks
-    assert_equal [:reset_callback_record, :foo], self.class.setup_callback_chain
+    assert_equal [:reset_callback_record, :foo], self.class.setup_callback_chain.map(&:method)
     assert_equal [:foo], @called_back
-    assert_equal [:foo, :sentinel, :foo], self.class.teardown_callback_chain
+    assert_equal [:foo, :sentinel, :foo], self.class.teardown_callback_chain.map(&:method)
   end
 
   protected
@@ -104,9 +104,9 @@ class SubclassSetupAndTeardownTest < SetupAndTeardownTest
   teardown :bar
 
   def test_inherited_setup_callbacks
-    assert_equal [:reset_callback_record, :foo, :bar], self.class.setup_callback_chain
+    assert_equal [:reset_callback_record, :foo, :bar], self.class.setup_callback_chain.map(&:method)
     assert_equal [:foo, :bar], @called_back
-    assert_equal [:foo, :sentinel, :foo, :bar], self.class.teardown_callback_chain
+    assert_equal [:foo, :sentinel, :foo, :bar], self.class.teardown_callback_chain.map(&:method)
   end
 
   protected