--- /dev/null
+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 = :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 = []
+
+ # 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
+
+ # An internal stack used to record which constants are loaded by any block.
+ mattr_accessor :constant_watch_stack
+ self.constant_watch_stack = []
+
+ # Module includes this module
+ module ModuleConstMissing #:nodoc:
+ def self.included(base) #:nodoc:
+ base.class_eval do
+ unless defined? const_missing_without_dependencies
+ alias_method_chain :const_missing, :dependencies
+ end
+ end
+ end
+
+ def self.excluded(base) #:nodoc:
+ base.class_eval do
+ if defined? const_missing_without_dependencies
+ undef_method :const_missing
+ alias_method :const_missing, :const_missing_without_dependencies
+ undef_method :const_missing_without_dependencies
+ 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_with_dependencies(class_id)
+ ActiveSupport::Dependencies.load_missing_constant self, class_id
+ end
+
+ def unloadable(const_desc = self)
+ super(const_desc)
+ end
+ end
+
+ # Class includes this module
+ module ClassConstMissing #:nodoc:
+ def const_missing(const_name)
+ if [Object, Kernel].include?(self) || parent == self
+ super
+ else
+ begin
+ begin
+ Dependencies.load_missing_constant self, const_name
+ rescue NameError
+ parent.send :const_missing, const_name
+ end
+ rescue NameError => e
+ # Make sure that the name we are missing is the one that caused the error
+ parent_qualified_name = Dependencies.qualified_name_for parent, const_name
+ raise unless e.missing_name? parent_qualified_name
+ qualified_name = Dependencies.qualified_name_for self, const_name
+ raise NameError.new("uninitialized constant #{qualified_name}").copy_blame!(e)
+ end
+ end
+ end
+ end
+
+ # Object includes this module
+ module Loadable #:nodoc:
+ def self.included(base) #:nodoc:
+ base.class_eval do
+ unless defined? load_without_new_constant_marking
+ alias_method_chain :load, :new_constant_marking
+ end
+ end
+ end
+
+ def self.excluded(base) #:nodoc:
+ base.class_eval do
+ if defined? load_without_new_constant_marking
+ undef_method :load
+ alias_method :load, :load_without_new_constant_marking
+ undef_method :load_without_new_constant_marking
+ end
+ end
+ end
+
+ def require_or_load(file_name)
+ Dependencies.require_or_load(file_name)
+ end
+
+ def require_dependency(file_name)
+ Dependencies.depend_on(file_name)
+ end
+
+ def require_association(file_name)
+ Dependencies.associate_with(file_name)
+ end
+
+ def load_with_new_constant_marking(file, *extras) #:nodoc:
+ if Dependencies.load?
+ Dependencies.new_constants_in(Object) { load_without_new_constant_marking(file, *extras) }
+ else
+ load_without_new_constant_marking(file, *extras)
+ end
+ rescue Exception => exception # errors from loading file
+ exception.blame_file! file
+ raise
+ end
+
+ def require(file, *extras) #:nodoc:
+ if Dependencies.load?
+ Dependencies.new_constants_in(Object) { super }
+ else
+ super
+ end
+ rescue Exception => exception # errors from required file
+ exception.blame_file! file
+ raise
+ 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.instance_eval { include Loadable }
+ Module.instance_eval { include ModuleConstMissing }
+ Class.instance_eval { include ClassConstMissing }
+ Exception.instance_eval { include Blamable }
+ true
+ end
+
+ def unhook!
+ ModuleConstMissing.excluded(Module)
+ Loadable.excluded(Object)
+ true
+ end
+
+ def load?
+ mechanism == :load
+ end
+
+ def depend_on(file_name, swallow_load_errors = false)
+ path = search_for_file(file_name)
+ require_or_load(path || file_name)
+ rescue LoadError
+ raise unless swallow_load_errors
+ 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)
+ raise NameError, "#{path.inspect} is not a valid constant name!" unless
+ /^(::)?([A-Z]\w*)(::[A-Z]\w*)*$/ =~ path
+
+ names = path.to_s.split('::')
+ names.shift if names.first.empty?
+
+ # We can't use defined? because it will invoke const_missing for the parent
+ # of the name we are checking.
+ names.inject(Object) do |mod, name|
+ return false unless uninherited_const_defined?(mod, name)
+ mod.const_get name
+ end
+ return true
+ end
+
+ if Module.method(:const_defined?).arity == 1
+ # Does this module define this constant?
+ # Wrapper to accomodate changing Module#const_defined? in Ruby 1.9
+ def uninherited_const_defined?(mod, const)
+ mod.const_defined?(const)
+ end
+ else
+ def uninherited_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)
+ path = $1 if path =~ /\A(.*)\.rb\Z/
+ expanded_path = File.expand_path(path)
+
+ bases.collect do |root|
+ expanded_root = File.expand_path(root)
+ next unless %r{\A#{Regexp.escape(expanded_root)}(/|\\)} =~ expanded_path
+
+ nesting = expanded_path[(expanded_root.size)..-1]
+ nesting = nesting[1..-1] if nesting && nesting[0] == ?/
+ next if nesting.blank?
+ nesting_camel = nesting.camelize
+ begin
+ qualified_const_defined?(nesting_camel)
+ rescue NameError
+ next
+ end
+
+ [
+ nesting.camelize,
+ # Special case: application.rb might define ApplicationControlller.
+ ('ApplicationController' if nesting == 'application')
+ ]
+ end.flatten.compact.uniq
+ end
+
+ # Search for a file in load_paths matching the provided suffix.
+ def search_for_file(path_suffix)
+ path_suffix = path_suffix + '.rb' unless path_suffix.ends_with? '.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 = load_without_new_constant_marking 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
+ (%w(Object Kernel).include? mod_name) ? 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
+ if from_mod == Kernel
+ if ::Object.const_defined?(const_name)
+ log "Returning Object::#{const_name} for Kernel::#{const_name}"
+ return ::Object.const_get(const_name)
+ else
+ log "Substituting Object for Kernel"
+ from_mod = Object
+ end
+ end
+
+ # If we have an anonymous module, all we can do is attempt to load from Object.
+ from_mod = Object if from_mod.name.blank?
+
+ unless qualified_const_defined?(from_mod.name) && from_mod.name.constantize.object_id == from_mod.object_id
+ 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 uninherited_const_defined?(from_mod, const_name)
+
+ qualified_name = qualified_name_for from_mod, const_name
+ path_suffix = qualified_name.underscore
+ name_error = NameError.new("uninitialized constant #{qualified_name}")
+
+ 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 uninherited_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| uninherited_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
+ explicitly_unloadable_constants.each { |const| remove_constant const }
+ 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.name.blank?
+ 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)
+
+ # Build the watch frames. Each frame is a tuple of
+ # [module_name_as_string, constants_defined_elsewhere]
+ watch_frames = descs.collect do |desc|
+ if desc.is_a? Module
+ mod_name = desc.name
+ initial_constants = desc.local_constant_names
+ elsif desc.is_a?(String) || desc.is_a?(Symbol)
+ mod_name = desc.to_s
+
+ # Handle the case where the module has yet to be defined.
+ initial_constants = if qualified_const_defined?(mod_name)
+ mod_name.constantize.local_constant_names
+ else
+ []
+ end
+ else
+ raise Argument, "#{desc.inspect} does not describe a module!"
+ end
+
+ [mod_name, initial_constants]
+ end
+
+ constant_watch_stack.concat watch_frames
+
+ aborting = true
+ begin
+ yield # Now yield to the code that is to define new constants.
+ aborting = false
+ ensure
+ # Find the new constants.
+ new_constants = watch_frames.collect do |mod_name, prior_constants|
+ # Module still doesn't exist? Treat it as if it has no constants.
+ next [] unless qualified_const_defined?(mod_name)
+
+ mod = mod_name.constantize
+ next [] unless mod.is_a? Module
+ new_constants = mod.local_constant_names - prior_constants
+
+ # Make sure no other frames takes credit for these constants.
+ constant_watch_stack.each do |frame_name, constants|
+ constants.concat new_constants if frame_name == mod_name
+ end
+
+ new_constants.collect do |suffix|
+ mod_name == "Object" ? suffix : "#{mod_name}::#{suffix}"
+ end
+ end.flatten
+
+ log "New constants: #{new_constants * ', '}"
+
+ if aborting
+ log "Error during loading, removing partially loaded constants "
+ new_constants.each { |name| remove_constant name }
+ new_constants.clear
+ end
+ end
+
+ return new_constants
+ ensure
+ # Remove the stack frames that we added.
+ if defined?(watch_frames) && ! watch_frames.blank?
+ frame_ids = watch_frames.collect { |frame| frame.object_id }
+ constant_watch_stack.delete_if do |watch_frame|
+ frame_ids.include? watch_frame.object_id
+ end
+ end
+ 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_DEFAULT_LOGGER)
+ RAILS_DEFAULT_LOGGER.warn "Your environment.rb uses the old syntax, it may not continue to work in future releases."
+ RAILS_DEFAULT_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.starts_with?('::') ? desc[2..-1] : desc
+ when Symbol then desc.to_s
+ when Module
+ raise ArgumentError, "Anonymous modules have no name to be referenced by" if desc.name.blank?
+ desc.name
+ else raise TypeError, "Not a valid constant descriptor: #{desc.inspect}"
+ end
+ end
+
+ def remove_constant(const) #:nodoc:
+ return false unless qualified_const_defined? const
+
+ const = $1 if /\A::(.*)\Z/ =~ const.to_s
+ names = const.to_s.split('::')
+ if names.size == 1 # It's under Object
+ parent = Object
+ else
+ parent = (names[0..-2] * '::').constantize
+ end
+
+ log "removing constant #{const}"
+ parent.instance_eval { remove_const names.last }
+ 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!
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