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 namespace.constantize, 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 accomodate 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 || '' 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!