require 'set'
require 'thread'
require 'pathname'
require 'active_support/core_ext/module/aliasing'
require 'active_support/core_ext/module/attribute_accessors'
require 'active_support/core_ext/module/introspection'
require 'active_support/core_ext/module/anonymous'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/load_error'
require 'active_support/core_ext/name_error'
require 'active_support/core_ext/string/starts_ends_with'
require 'active_support/inflector'
module ActiveSupport #:nodoc:
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 = ENV['NO_RELOAD'] ? :require : :load
# The set of directories from which we may automatically load files. Files
# under these directories will be reloaded on each request in development mode,
# unless the directory also appears in load_once_paths.
mattr_accessor :load_paths
self.load_paths = []
# The set of directories from which automatically loaded constants are loaded
# only once. All directories in this set must also be present in +load_paths+.
mattr_accessor :load_once_paths
self.load_once_paths = []
# An array of qualified constant names that have been loaded. Adding a name to
# this array will cause it to be unloaded the next time Dependencies are cleared.
mattr_accessor :autoloaded_constants
self.autoloaded_constants = []
mattr_accessor :references
self.references = {}
# An array of constant names that need to be unloaded on every request. Used
# to allow arbitrary constants to be marked for unloading.
mattr_accessor :explicitly_unloadable_constants
self.explicitly_unloadable_constants = []
# The logger is used for generating information on the action run-time (including benchmarking) if available.
# Can be set to nil for no logging. Compatible with both Ruby's own Logger and Log4r loggers.
mattr_accessor :logger
# Set to true to enable logging of const_missing and file loads
mattr_accessor :log_activity
self.log_activity = false
class WatchStack < Array
def initialize
@mutex = Mutex.new
end
def self.locked(*methods)
methods.each { |m| class_eval "def #{m}(*) lock { super } end", __FILE__, __LINE__ }
end
def get(key)
(val = assoc(key)) ? val[1] : []
end
locked :concat, :each, :delete_if, :<<
def new_constants_for(frames)
constants = []
frames.each do |mod_name, prior_constants|
mod = Inflector.constantize(mod_name) if Dependencies.qualified_const_defined?(mod_name)
next unless mod.is_a?(Module)
new_constants = mod.local_constant_names - prior_constants
get(mod_name).concat(new_constants)
new_constants.each do |suffix|
constants << ([mod_name, suffix] - ["Object"]).join("::")
end
end
constants
end
# Add a set of modules to the watch stack, remembering the initial constants
def add_modules(modules)
list = modules.map do |desc|
name = Dependencies.to_constant_name(desc)
consts = Dependencies.qualified_const_defined?(name) ?
Inflector.constantize(name).local_constant_names : []
[name, consts]
end
concat(list)
list
end
def lock
@mutex.synchronize { yield self }
end
end
# An internal stack used to record which constants are loaded by any block.
mattr_accessor :constant_watch_stack
self.constant_watch_stack = WatchStack.new
# Module includes this module
module ModuleConstMissing #:nodoc:
def self.append_features(base)
base.class_eval do
# Emulate #exclude via an ivar
return if defined?(@_const_missing) && @_const_missing
@_const_missing = instance_method(:const_missing)
remove_method(:const_missing)
end
super
end
def self.exclude_from(base)
base.class_eval do
define_method :const_missing, @_const_missing
@_const_missing = nil
end
end
# Use const_missing to autoload associations so we don't have to
# require_association when using single-table inheritance.
def const_missing(const_name, nesting = nil)
klass_name = name.presence || "Object"
if !nesting
# We'll assume that the nesting of Foo::Bar is ["Foo::Bar", "Foo"]
# even though it might not be, such as in the case of
# class Foo::Bar; Baz; end
nesting = []
klass_name.to_s.scan(/::|$/) { nesting.unshift $` }
end
# If there are multiple levels of nesting to search under, the top
# level is the one we want to report as the lookup fail.
error = nil
nesting.each do |namespace|
begin
return Dependencies.load_missing_constant Inflector.constantize(namespace), const_name
rescue NoMethodError then raise
rescue NameError => e
error ||= e
end
end
# Raise the first error for this set. If this const_missing came from an
# earlier const_missing, this will result in the real error bubbling
# all the way up
raise error
end
def unloadable(const_desc = self)
super(const_desc)
end
end
# Object includes this module
module Loadable #:nodoc:
def self.exclude_from(base)
base.class_eval { define_method(:load, Kernel.instance_method(:load)) }
end
def require_or_load(file_name)
Dependencies.require_or_load(file_name)
end
def require_dependency(file_name, message = "No such file to load -- %s")
unless file_name.is_a?(String)
raise ArgumentError, "the file name must be a String -- you passed #{file_name.inspect}"
end
Dependencies.depend_on(file_name, false, message)
end
def require_association(file_name)
Dependencies.associate_with(file_name)
end
def load_dependency(file)
if Dependencies.load?
Dependencies.new_constants_in(Object) { yield }.presence
else
yield
end
rescue Exception => exception # errors from loading file
exception.blame_file! file
raise
end
def load(file, *)
load_dependency(file) { super }
end
def require(file, *)
load_dependency(file) { super }
end
# Mark the given constant as unloadable. Unloadable constants are removed each
# time dependencies are cleared.
#
# Note that marking a constant for unloading need only be done once. Setup
# or init scripts may list each unloadable constant that may need unloading;
# each constant will be removed for every subsequent clear, as opposed to for
# the first clear.
#
# The provided constant descriptor may be a (non-anonymous) module or class,
# or a qualified constant name as a string or symbol.
#
# Returns true if the constant was not previously marked for unloading, false
# otherwise.
def unloadable(const_desc)
Dependencies.mark_for_unload const_desc
end
end
# Exception file-blaming
module Blamable #: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 occurred while loading the following files:\n #{blamed_files.join "\n "}"
end
def copy_blame!(exc)
@blamed_files = exc.blamed_files.clone
self
end
end
def hook!
Object.class_eval { include Loadable }
Module.class_eval { include ModuleConstMissing }
Exception.class_eval { include Blamable }
true
end
def unhook!
ModuleConstMissing.exclude_from(Module)
Loadable.exclude_from(Object)
true
end
def load?
mechanism == :load
end
def depend_on(file_name, swallow_load_errors = false, message = "No such file to load -- %s.rb")
path = search_for_file(file_name)
require_or_load(path || file_name)
rescue LoadError => load_error
unless swallow_load_errors
if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
raise LoadError.new(message % file_name).copy_blame!(load_error)
end
raise
end
end
def associate_with(file_name)
depend_on(file_name, true)
end
def clear
log_call
loaded.clear
remove_unloadable_constants!
end
def require_or_load(file_name, const_path = nil)
log_call file_name, const_path
file_name = $1 if file_name =~ /^(.*)\.rb$/
expanded = File.expand_path(file_name)
return if loaded.include?(expanded)
# Record that we've seen this file *before* loading it to avoid an
# infinite loop with mutual dependencies.
loaded << expanded
begin
if load?
log "loading #{file_name}"
# Enable warnings iff this file has not been loaded before and
# warnings_on_first_load is set.
load_args = ["#{file_name}.rb"]
load_args << const_path unless const_path.nil?
if !warnings_on_first_load or history.include?(expanded)
result = load_file(*load_args)
else
enable_warnings { result = load_file(*load_args) }
end
else
log "requiring #{file_name}"
result = require file_name
end
rescue Exception
loaded.delete expanded
raise
end
# Record history *after* loading so first load gets warnings.
history << expanded
return result
end
# Is the provided constant path defined?
def qualified_const_defined?(path)
names = path.sub(/^::/, '').to_s.split('::')
names.inject(Object) do |mod, name|
return false unless local_const_defined?(mod, name)
mod.const_get name
end
end
if Module.method(:const_defined?).arity == 1
# Does this module define this constant?
# Wrapper to accommodate changing Module#const_defined? in Ruby 1.9
def local_const_defined?(mod, const)
mod.const_defined?(const)
end
else
def local_const_defined?(mod, const) #:nodoc:
mod.const_defined?(const, false)
end
end
# Given +path+, a filesystem path to a ruby file, return an array of constant
# paths which would cause Dependencies to attempt to load this file.
def loadable_constants_for_path(path, bases = load_paths)
expanded_path = Pathname.new(path[/\A(.*?)(\.rb)?\Z/, 1]).expand_path
bases.inject([]) do |paths, root|
expanded_root = Pathname.new(root).expand_path
nesting = expanded_path.relative_path_from(expanded_root).to_s
next paths if nesting =~ /\.\./
paths << nesting.camelize
end.uniq
end
# Search for a file in load_paths matching the provided suffix.
def search_for_file(path_suffix)
path_suffix = path_suffix.sub(/(\.rb)?$/, ".rb")
load_paths.each do |root|
path = File.join(root, path_suffix)
return path if File.file? path
end
nil # Gee, I sure wish we had first_match ;-)
end
# Does the provided path_suffix correspond to an autoloadable module?
# Instead of returning a boolean, the autoload base for this module is returned.
def autoloadable_module?(path_suffix)
load_paths.each do |load_path|
return load_path if File.directory? File.join(load_path, path_suffix)
end
nil
end
def load_once_path?(path)
load_once_paths.any? { |base| path.starts_with? base }
end
# Attempt to autoload the provided module name by searching for a directory
# matching the expect path suffix. If found, the module is created and assigned
# to +into+'s constants with the name +const_name+. Provided that the directory
# was loaded from a reloadable base path, it is added to the set of constants
# that are to be unloaded.
def autoload_module!(into, const_name, qualified_name, path_suffix)
return nil unless base_path = autoloadable_module?(path_suffix)
mod = Module.new
into.const_set const_name, mod
autoloaded_constants << qualified_name unless load_once_paths.include?(base_path)
return mod
end
# Load the file at the provided path. +const_paths+ is a set of qualified
# constant names. When loading the file, Dependencies will watch for the
# addition of these constants. Each that is defined will be marked as
# autoloaded, and will be removed when Dependencies.clear is next called.
#
# If the second parameter is left off, then Dependencies will construct a set
# of names that the file at +path+ may define. See
# +loadable_constants_for_path+ for more details.
def load_file(path, const_paths = loadable_constants_for_path(path))
log_call path, const_paths
const_paths = [const_paths].compact unless const_paths.is_a? Array
parent_paths = const_paths.collect { |const_path| /(.*)::[^:]+\Z/ =~ const_path ? $1 : :Object }
result = nil
newly_defined_paths = new_constants_in(*parent_paths) do
result = Kernel.load path
end
autoloaded_constants.concat newly_defined_paths unless load_once_path?(path)
autoloaded_constants.uniq!
log "loading #{path} defined #{newly_defined_paths * ', '}" unless newly_defined_paths.empty?
return result
end
# Return the constant path for the provided parent and constant name.
def qualified_name_for(mod, name)
mod_name = to_constant_name mod
mod_name == "Object" ? name.to_s : "#{mod_name}::#{name}"
end
# Load the constant named +const_name+ which is missing from +from_mod+. If
# it is not possible to load the constant into from_mod, try its parent module
# using const_missing.
def load_missing_constant(from_mod, const_name)
log_call from_mod, const_name
unless qualified_const_defined?(from_mod.name) && Inflector.constantize(from_mod.name).equal?(from_mod)
raise ArgumentError, "A copy of #{from_mod} has been removed from the module tree but is still active!"
end
raise ArgumentError, "#{from_mod} is not missing constant #{const_name}!" if local_const_defined?(from_mod, const_name)
qualified_name = qualified_name_for from_mod, const_name
path_suffix = qualified_name.underscore
trace = caller.reject {|l| l =~ %r{#{Regexp.escape(__FILE__)}}}
name_error = NameError.new("uninitialized constant #{qualified_name}")
name_error.set_backtrace(trace)
file_path = search_for_file(path_suffix)
if file_path && ! loaded.include?(File.expand_path(file_path)) # We found a matching file to load
require_or_load file_path
raise LoadError, "Expected #{file_path} to define #{qualified_name}" unless local_const_defined?(from_mod, const_name)
return from_mod.const_get(const_name)
elsif mod = autoload_module!(from_mod, const_name, qualified_name, path_suffix)
return mod
elsif (parent = from_mod.parent) && parent != from_mod &&
! from_mod.parents.any? { |p| local_const_defined?(p, const_name) }
# If our parents do not have a constant named +const_name+ then we are free
# to attempt to load upwards. If they do have such a constant, then this
# const_missing must be due to from_mod::const_name, which should not
# return constants from from_mod's parents.
begin
return parent.const_missing(const_name)
rescue NameError => e
raise unless e.missing_name? qualified_name_for(parent, const_name)
raise name_error
end
else
raise name_error
end
end
# Remove the constants that have been autoloaded, and those that have been
# marked for unloading.
def remove_unloadable_constants!
autoloaded_constants.each { |const| remove_constant const }
autoloaded_constants.clear
Reference.clear!
explicitly_unloadable_constants.each { |const| remove_constant const }
end
class Reference
@@constants = Hash.new { |h, k| h[k] = Inflector.constantize(k) }
attr_reader :name
def initialize(name)
@name = name.to_s
@@constants[@name] = name if name.respond_to?(:name)
end
def get
@@constants[@name]
end
def self.clear!
@@constants.clear
end
end
def ref(name)
references[name] ||= Reference.new(name)
end
def constantize(name)
ref(name).get
end
# Determine if the given constant has been automatically loaded.
def autoloaded?(desc)
# No name => anonymous module.
return false if desc.is_a?(Module) && desc.anonymous?
name = to_constant_name desc
return false unless qualified_const_defined? name
return autoloaded_constants.include?(name)
end
# Will the provided constant descriptor be unloaded?
def will_unload?(const_desc)
autoloaded?(const_desc) ||
explicitly_unloadable_constants.include?(to_constant_name(const_desc))
end
# Mark the provided constant name for unloading. This constant will be
# unloaded on each request, not just the next one.
def mark_for_unload(const_desc)
name = to_constant_name const_desc
if explicitly_unloadable_constants.include? name
return false
else
explicitly_unloadable_constants << name
return true
end
end
# Run the provided block and detect the new constants that were loaded during
# its execution. Constants may only be regarded as 'new' once -- so if the
# block calls +new_constants_in+ again, then the constants defined within the
# inner call will not be reported in this one.
#
# If the provided block does not run to completion, and instead raises an
# exception, any new constants are regarded as being only partially defined
# and will be removed immediately.
def new_constants_in(*descs)
log_call(*descs)
watch_frames = constant_watch_stack.add_modules(descs)
aborting = true
begin
yield # Now yield to the code that is to define new constants.
aborting = false
ensure
new_constants = constant_watch_stack.new_constants_for(watch_frames)
log "New constants: #{new_constants * ', '}"
return new_constants unless aborting
log "Error during loading, removing partially loaded constants "
new_constants.each {|c| remove_constant(c) }.clear
end
return []
ensure
# Remove the stack frames that we added.
watch_frames.each {|f| constant_watch_stack.delete(f) } if watch_frames.present?
end
class LoadingModule #:nodoc:
# Old style environment.rb referenced this method directly. Please note, it doesn't
# actually *do* anything any more.
def self.root(*args)
if defined?(Rails) && Rails.logger
Rails.logger.warn "Your environment.rb uses the old syntax, it may not continue to work in future releases."
Rails.logger.warn "For upgrade instructions please see: http://manuals.rubyonrails.com/read/book/19"
end
end
end
# Convert the provided const desc to a qualified constant name (as a string).
# A module, class, symbol, or string may be provided.
def to_constant_name(desc) #:nodoc:
name = case desc
when String then desc.sub(/^::/, '')
when Symbol then desc.to_s
when Module
desc.name.presence ||
raise(ArgumentError, "Anonymous modules have no name to be referenced by")
else raise TypeError, "Not a valid constant descriptor: #{desc.inspect}"
end
end
def remove_constant(const) #:nodoc:
return false unless qualified_const_defined? const
# Normalize ::Foo, Foo, Object::Foo, and ::Object::Foo to Object::Foo
names = const.to_s.sub(/^::(Object)?/, 'Object::').split("::")
to_remove = names.pop
parent = Inflector.constantize(names * '::')
log "removing constant #{const}"
parent.instance_eval { remove_const to_remove }
return true
end
protected
def log_call(*args)
if logger && log_activity
arg_str = args.collect { |arg| arg.inspect } * ', '
/in `([a-z_\?\!]+)'/ =~ caller(1).first
selector = $1 || '<unknown>'
log "called #{selector}(#{arg_str})"
end
end
def log(msg)
if logger && log_activity
logger.debug "Dependencies: #{msg}"
end
end
end
end
ActiveSupport::Dependencies.hook!
