require 'set'
require File.dirname(__FILE__) + '/core_ext/module/attribute_accessors'
require File.dirname(__FILE__) + '/core_ext/load_error'
require File.dirname(__FILE__) + '/core_ext/kernel'
module Dependencies #:nodoc:
extend self
# Should we turn on Ruby warnings on the first load of dependent files?
mattr_accessor :warnings_on_first_load
self.warnings_on_first_load = false
# All files ever loaded.
mattr_accessor :history
self.history = Set.new
# All files currently loaded.
mattr_accessor :loaded
self.loaded = Set.new
# Should we load files or require them?
mattr_accessor :mechanism
self.mechanism = :load
def load?
mechanism == :load
end
def depend_on(file_name, swallow_load_errors = false)
require_or_load(file_name)
rescue LoadError
raise unless swallow_load_errors
end
def associate_with(file_name)
depend_on(file_name, true)
end
def clear
loaded.clear
end
def require_or_load(file_name)
file_name = $1 if file_name =~ /^(.*)\.rb$/
return if loaded.include?(file_name)
# Record that we've seen this file *before* loading it to avoid an
# infinite loop with mutual dependencies.
loaded << file_name
if load?
begin
# Enable warnings iff this file has not been loaded before and
# warnings_on_first_load is set.
if !warnings_on_first_load or history.include?(file_name)
load "#{file_name}.rb"
else
enable_warnings { load "#{file_name}.rb" }
end
rescue
loaded.delete file_name
raise
end
else
require file_name
end
# Record history *after* loading so first load gets warnings.
history << file_name
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)
loaded_file = 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)
# Throw an error if we load the file but we don't find the Object we expect
if loaded_file and not self.const_defined?(name)
msg = "Already loaded file '#{fs_path}' but '#{name.to_s}' was not set, perhaps you need to rename '#{fs_path}'?"
raise LoadError, msg
end
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
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:
# Rename the original handler so we can chain it to the new one
alias :rails_original_const_missing :const_missing
def parent
parent_name = name.split('::')[0..-2] * '::'
parent_name.empty? ? Object : parent_name.constantize
end
def as_load_path
if self == Object || self == Kernel
''
elsif is_a? Class
parent == self ? '' : parent.as_load_path
else
name.split('::').collect do |word|
word.underscore
end * '/'
end
end
# 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) && Object::Controllers.const_available?(class_id)
return Object::Controllers.const_get(class_id)
end
file_name = class_id.to_s.demodulize.underscore
file_path = as_load_path.empty? ? file_name : "#{as_load_path}/#{file_name}"
begin
require_dependency(file_path)
brief_name = self == Object ? '' : "#{name}::"
raise NameError.new("uninitialized constant #{brief_name}#{class_id}") unless const_defined?(class_id)
return const_get(class_id)
rescue MissingSourceFile => e
# Re-raise the error if it does not concern the file we were trying to load.
raise unless e.is_missing? file_path
# Look for a directory in the load path that we ought to load.
if $LOAD_PATH.any? { |base| File.directory? "#{base}/#{file_path}" }
mod = Module.new
const_set class_id, mod # Create the new module
return mod
end
if parent && parent != self
suppress(NameError) do
return parent.send(:const_missing, class_id)
end
end
raise NameError.new("uninitialized constant #{class_id}").copy_blame!(e)
end
end
end
class Class
def const_missing(class_id)
if [Object, Kernel].include?(self) || parent == self
super
else
parent.send :const_missing, class_id
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
