Massive cleanup in Railties and load stack.

1 files changed, 107 insertions, 0 deletions

diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
new file mode 100644
index 0000000000..21c78036bd
--- /dev/null
+++ b/railties/lib/rails/engine.rb
@@ -0,0 +1,107 @@
+require 'active_support/core_ext/module/delegation'
+
+module Rails
+  # TODO Move I18n and views path setup
+  class Engine < Railtie
+
+    class << self
+      attr_accessor :called_from
+
+      def root
+        @root ||= find_root_with_file_flag("lib")
+      end
+
+      def config
+        @config ||= Configuration.new(root)
+      end
+
+      def inherited(base)
+        base.called_from = begin
+          call_stack = caller.map { |p| p.split(':').first }
+          File.dirname(call_stack.detect { |p| p !~ %r[railties/lib/rails|rack/lib/rack] })
+        end
+        super
+      end
+
+    protected
+
+      def find_root_with_file_flag(flag, default=nil)
+        root_path = self.called_from
+
+        while root_path && File.directory?(root_path) && !File.exist?("#{root_path}/#{flag}")
+          parent = File.dirname(root_path)
+          root_path = parent != root_path && parent
+        end
+
+        root = File.exist?("#{root_path}/flag") ? root_path : default
+
+        raise "Could not find root path for #{self}" unless root
+
+        RUBY_PLATFORM =~ /(:?mswin|mingw)/ ?
+          Pathname.new(root).expand_path :
+          Pathname.new(root).realpath
+      end
+    end
+
+    delegate :root, :config, :to => :'self.class'
+    delegate :middleware,    :to => :config
+
+    # Add configured load paths to ruby load paths and remove duplicates.
+    initializer :set_load_path, :before => :container do
+      config.paths.add_to_load_path
+      $LOAD_PATH.uniq!
+    end
+
+    # Set the paths from which Rails will automatically load source files,
+    # and the load_once paths.
+    initializer :set_autoload_paths, :before => :container do
+      require 'active_support/dependencies'
+
+      ActiveSupport::Dependencies.load_paths = expand_load_path(config.load_paths)
+      ActiveSupport::Dependencies.load_once_paths = expand_load_path(config.load_once_paths)
+
+      extra = ActiveSupport::Dependencies.load_once_paths - ActiveSupport::Dependencies.load_paths
+
+      unless extra.empty?
+        abort <<-end_error
+          load_once_paths must be a subset of the load_paths.
+          Extra items in load_once_paths: #{extra * ','}
+        end_error
+      end
+
+      # Freeze the arrays so future modifications will fail rather than do nothing mysteriously
+      config.load_once_paths.freeze
+    end
+
+    initializer :load_application_initializers do
+      Dir["#{root}/config/initializers/**/*.rb"].sort.each do |initializer|
+        load(initializer)
+      end
+    end
+
+    # Routing must be initialized after plugins to allow the former to extend the routes
+    initializer :initialize_routing do |app|
+      app.route_configuration_files.concat(config.paths.config.routes.to_a)
+    end
+
+    # Eager load application classes
+    initializer :load_application_classes do |app|
+      next if $rails_rake_task
+
+      if app.config.cache_classes
+        config.eager_load_paths.each do |load_path|
+          matcher = /\A#{Regexp.escape(load_path)}(.*)\.rb\Z/
+          Dir.glob("#{load_path}/**/*.rb").sort.each do |file|
+            require_dependency file.sub(matcher, '\1')
+          end
+        end
+      end
+    end
+
+  private
+
+    def expand_load_path(load_paths)
+      load_paths.map { |path| Dir.glob(path.to_s) }.flatten.uniq
+    end
+  end
+end
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