1 files changed, 49 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/dependencies/autoload.rb b/activesupport/lib/active_support/dependencies/autoload.rb
new file mode 100644
index 0000000000..96ab04c61a
--- /dev/null
+++ b/activesupport/lib/active_support/dependencies/autoload.rb
@@ -0,0 +1,49 @@
+require "active_support/inflector/methods"
+
+module ActiveSupport
+  module Autoload
+    @@autoloads = {}
+    @@under_path = nil
+    @@at_path = nil
+    @@autoload_defer = false
+
+    def autoload(const_name, path = @@at_path)
+      full = [self.name, @@under_path, const_name.to_s, path].compact.join("::")
+      location = path || Inflector.underscore(full)
+
+      unless @@autoload_defer
+        @@autoloads[const_name] = location
+      end
+      super const_name, location
+    end
+
+    def autoload_under(path)
+      @@under_path, old_path = path, @@under_path
+      yield
+    ensure
+      @@under_path = old_path
+    end
+
+    def autoload_at(path)
+      @@at_path, old_path = path, @@at_path
+      yield
+    ensure
+      @@at_path = old_path
+    end
+
+    def deferrable
+      old_defer, @@autoload_defer = @@autoload_defer, true
+      yield
+    ensure
+      @@autoload_defer = old_defer
+    end
+
+    def self.eager_autoload!
+      @@autoloads.values.each { |file| require file }
+    end
+
+    def autoloads
+      @@autoloads
+    end
+  end
+end