Reorganize autoloads:

  * A new module (ActiveSupport::Autoload) is provide that extends
    autoloading with new behavior.
  * All autoloads in modules that have extended ActiveSupport::Autoload
    will be eagerly required in threadsafe environments
  * Autoloads can optionally leave off the path if the path is the same
    as full_constant_name.underscore
  * It is possible to specify that a group of autoloads live under an
    additional path. For instance, all of ActionDispatch's middlewares
    are ActionDispatch::MiddlewareName, but they live under 
    "action_dispatch/middlewares/middleware_name"
  * It is possible to specify that a group of autoloads are all found
    at the same path. For instance, a number of exceptions might all
    be declared there.
  * One consequence of this is that testing-related constants are not
    autoloaded. To get the testing helpers for a given component,
    require "component_name/test_case". For instance, "action_controller/test_case".
  * test_help.rb, which is automatically required by a Rails application's
    test helper, requires the test_case.rb for all active components, so
    this change will not be disruptive in existing or new applications.

1 files changed, 37 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..973875f895
--- /dev/null
+++ b/activesupport/lib/active_support/dependencies/autoload.rb
@@ -0,0 +1,37 @@
+require "active_support/inflector/methods"
+
+module ActiveSupport
+  module Autoload
+
+    @@autoloads = {}
+    @@under_path = nil
+    @@at_path = nil
+
+    def autoload(const_name, path = @@at_path)
+      full = [self.name, @@under_path, const_name.to_s, path].compact.join("::")
+      location = path || Inflector.underscore(full)
+
+      @@autoloads[const_name] = location
+      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 self.eager_autoload!
+      @@autoloads.values.each {|file| require file }
+    end
+
+  end
+end
\ No newline at end of file