require File.dirname(__FILE__) + '/module_attribute_accessors'
module Dependencies #:nodoc:
extend self
@@loaded = [ ]
mattr_accessor :loaded
@@mechanism = :load
mattr_accessor :mechanism
def load?
mechanism == :load
end
def depend_on(file_name, swallow_load_errors = false)
unless loaded.include?(file_name)
loaded << file_name
begin
require_or_load(file_name)
rescue LoadError
raise unless swallow_load_errors
end
end
end
def associate_with(file_name)
depend_on(file_name, true)
end
def clear
self.loaded = [ ]
end
def require_or_load(file_name)
file_name = "#{file_name}.rb" unless ! load? || file_name[-3..-1] == '.rb'
load? ? load(file_name) : require(file_name)
end
def remove_subclasses_for(*classes)
classes.each { |klass| klass.remove_subclasses }
end
# LoadingModules implement namespace-safe dynamic loading.
# They support automatic loading via const_missing, allowing contained items to be automatically
# loaded when required. No extra syntax is required, as expressions such as Controller::Admin::UserController
# load the relavent files automatically.
#
# Ruby-style modules are supported, as a folder named 'submodule' will load 'submodule.rb' when available.
class LoadingModule < Module #:nodoc:
attr_reader :path
attr_reader :root
class << self
def root(*load_paths)
RootLoadingModule.new(*load_paths)
end
end
def initialize(root, path=[])
@path = path.clone.freeze
@root = root
end
def root?() self.root == self end
def load_paths() self.root.load_paths end
# Load missing constants if possible.
def const_missing(name)
const_load!(name) ? const_get(name) : super(name)
end
# Load the controller class or a parent module.
def const_load!(name, file_name = nil)
file_name ||= 'application' if root? && name.to_s == 'ApplicationController'
path = self.path + [file_name || name]
load_paths.each do |load_path|
fs_path = load_path.filesystem_path(path)
next unless fs_path
case
when File.directory?(fs_path)
new_module = LoadingModule.new(self.root, self.path + [name])
self.const_set name, new_module
if self.root?
if Object.const_defined?(name)
msg = "Cannot load module #{name}: Object::#{name} is set to #{Object.const_get(name).inspect}"
raise NameError, msg
end
Object.const_set(name, new_module)
end
break
when File.file?(fs_path)
self.root.load_file!(fs_path)
# Import the loaded constant from Object provided we are the root node.
self.const_set(name, Object.const_get(name)) if self.root? && Object.const_defined?(name)
break
end
end
self.const_defined?(name)
end
# Is this name present or loadable?
# This method is used by Routes to find valid controllers.
def const_available?(name)
self.const_defined?(name) || load_paths.any? {|lp| lp.filesystem_path(path + [name])}
end
end
class RootLoadingModule < LoadingModule #:nodoc:
attr_reader :load_paths
def initialize(*paths)
@load_paths = paths.flatten.collect {|p| p.kind_of?(ConstantLoadPath) ? p : ConstantLoadPath.new(p)}
end
def root() self end
def path() [] end
# Load the source file at the given file path
def load_file!(file_path)
require_dependency(file_path)
end
# Erase all items in this module
def clear!
constants.each do |name|
Object.send(:remove_const, name) if Object.const_defined?(name) && Object.const_get(name).object_id == self.const_get(name).object_id
self.send(:remove_const, name)
end
end
end
# This object defines a path from which Constants can be loaded.
class ConstantLoadPath #:nodoc:
# Create a new load path with the filesystem path
def initialize(root) @root = root end
# Return nil if the path does not exist, or the path to a directory
# if the path leads to a module, or the path to a file if it leads to an object.
def filesystem_path(path, allow_module=true)
fs_path = [@root]
fs_path += path[0..-2].map {|name| const_name_to_module_name name}
if allow_module
result = File.join(fs_path, const_name_to_module_name(path.last))
return result if File.directory? result # Return the module path if one exists
end
result = File.join(fs_path, const_name_to_file_name(path.last))
File.file?(result) ? result : nil
end
def const_name_to_file_name(name)
name.to_s.underscore + '.rb'
end
def const_name_to_module_name(name)
name.to_s.underscore
end
end
end
Object.send(:define_method, :require_or_load) { |file_name| Dependencies.require_or_load(file_name) } unless Object.respond_to?(:require_or_load)
Object.send(:define_method, :require_dependency) { |file_name| Dependencies.depend_on(file_name) } unless Object.respond_to?(:require_dependency)
Object.send(:define_method, :require_association) { |file_name| Dependencies.associate_with(file_name) } unless Object.respond_to?(:require_association)
class Module #:nodoc:
# Use const_missing to autoload associations so we don't have to
# require_association when using single-table inheritance.
def const_missing(class_id)
if Object.const_defined?(:Controllers) and Object::Controllers.const_available?(class_id)
return Object::Controllers.const_get(class_id)
end
begin
require_dependency(class_id.to_s.demodulize.underscore)
if Object.const_defined?(class_id) then return Object.const_get(class_id) else raise LoadError end
rescue LoadError => e
raise NameError.new("uninitialized constant #{class_id}").copy_blame!(e)
end
end
end
class Object #:nodoc:
def load(file, *extras)
super(file, *extras)
rescue Object => exception
exception.blame_file! file
raise
end
def require(file, *extras)
super(file, *extras)
rescue Object => exception
exception.blame_file! file
raise
end
end
# Add file-blaming to exceptions
class Exception #:nodoc:
def blame_file!(file)
(@blamed_files ||= []).unshift file
end
def blamed_files
@blamed_files ||= []
end
def describe_blame
return nil if blamed_files.empty?
"This error occured while loading the following files:\n #{blamed_files.join "\n "}"
end
def copy_blame!(exc)
@blamed_files = exc.blamed_files.clone
self
end
end