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e302725751
If you require `nokogiri` from `app/models/user.rb`, dependencies.rb does not mark `Nokogiri` as an autoloaded constant, as expected. But the logic to detect these non-autoloaded constants is incomplete. See the tests defined in the patch for some cases incorrectly handled.
770 lines
26 KiB
Ruby
770 lines
26 KiB
Ruby
# frozen_string_literal: true
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require "set"
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require "thread"
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require "concurrent/map"
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require "pathname"
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require "active_support/core_ext/module/aliasing"
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require "active_support/core_ext/module/attribute_accessors"
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require "active_support/core_ext/module/introspection"
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require "active_support/core_ext/module/anonymous"
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require "active_support/core_ext/object/blank"
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require "active_support/core_ext/kernel/reporting"
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require "active_support/core_ext/load_error"
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require "active_support/core_ext/name_error"
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require "active_support/core_ext/string/starts_ends_with"
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require "active_support/dependencies/interlock"
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require "active_support/inflector"
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module ActiveSupport #:nodoc:
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module Dependencies #:nodoc:
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extend self
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mattr_accessor :interlock, default: Interlock.new
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# :doc:
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# Execute the supplied block without interference from any
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# concurrent loads.
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def self.run_interlock
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Dependencies.interlock.running { yield }
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end
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# Execute the supplied block while holding an exclusive lock,
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# preventing any other thread from being inside a #run_interlock
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# block at the same time.
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def self.load_interlock
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Dependencies.interlock.loading { yield }
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end
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# Execute the supplied block while holding an exclusive lock,
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# preventing any other thread from being inside a #run_interlock
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# block at the same time.
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def self.unload_interlock
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Dependencies.interlock.unloading { yield }
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end
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# :nodoc:
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# Should we turn on Ruby warnings on the first load of dependent files?
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mattr_accessor :warnings_on_first_load, default: false
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# All files ever loaded.
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mattr_accessor :history, default: Set.new
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# All files currently loaded.
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mattr_accessor :loaded, default: Set.new
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# Stack of files being loaded.
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mattr_accessor :loading, default: []
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# Should we load files or require them?
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mattr_accessor :mechanism, default: ENV["NO_RELOAD"] ? :require : :load
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# The set of directories from which we may automatically load files. Files
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# under these directories will be reloaded on each request in development mode,
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# unless the directory also appears in autoload_once_paths.
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mattr_accessor :autoload_paths, default: []
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# The set of directories from which automatically loaded constants are loaded
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# only once. All directories in this set must also be present in +autoload_paths+.
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mattr_accessor :autoload_once_paths, default: []
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# An array of qualified constant names that have been loaded. Adding a name
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# to this array will cause it to be unloaded the next time Dependencies are
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# cleared.
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mattr_accessor :autoloaded_constants, default: []
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# An array of constant names that need to be unloaded on every request. Used
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# to allow arbitrary constants to be marked for unloading.
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mattr_accessor :explicitly_unloadable_constants, default: []
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# The logger used when tracing autoloads.
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mattr_accessor :logger
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# If true, trace autoloads with +logger.debug+.
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mattr_accessor :verbose, default: false
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# The WatchStack keeps a stack of the modules being watched as files are
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# loaded. If a file in the process of being loaded (parent.rb) triggers the
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# load of another file (child.rb) the stack will ensure that child.rb
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# handles the new constants.
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#
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# If child.rb is being autoloaded, its constants will be added to
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# autoloaded_constants. If it was being required, they will be discarded.
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#
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# This is handled by walking back up the watch stack and adding the constants
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# found by child.rb to the list of original constants in parent.rb.
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class WatchStack
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include Enumerable
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# @watching is a stack of lists of constants being watched. For instance,
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# if parent.rb is autoloaded, the stack will look like [[Object]]. If
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# parent.rb then requires namespace/child.rb, the stack will look like
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# [[Object], [Namespace]].
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attr_reader :watching
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def initialize
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@watching = []
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@stack = Hash.new { |h, k| h[k] = [] }
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end
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def each(&block)
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@stack.each(&block)
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end
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def watching?
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!@watching.empty?
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end
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# Returns a list of new constants found since the last call to
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# <tt>watch_namespaces</tt>.
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def new_constants
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constants = []
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# Grab the list of namespaces that we're looking for new constants under
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@watching.last.each do |namespace|
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# Retrieve the constants that were present under the namespace when watch_namespaces
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# was originally called
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original_constants = @stack[namespace].last
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mod = Inflector.constantize(namespace) if Dependencies.qualified_const_defined?(namespace)
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next unless mod.is_a?(Module)
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# Get a list of the constants that were added
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new_constants = mod.constants(false) - original_constants
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# @stack[namespace] returns an Array of the constants that are being evaluated
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# for that namespace. For instance, if parent.rb requires child.rb, the first
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# element of @stack[Object] will be an Array of the constants that were present
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# before parent.rb was required. The second element will be an Array of the
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# constants that were present before child.rb was required.
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@stack[namespace].each do |namespace_constants|
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namespace_constants.concat(new_constants)
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end
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# Normalize the list of new constants, and add them to the list we will return
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new_constants.each do |suffix|
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constants << ([namespace, suffix] - ["Object"]).join("::")
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end
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end
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constants
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ensure
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# A call to new_constants is always called after a call to watch_namespaces
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pop_modules(@watching.pop)
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end
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# Add a set of modules to the watch stack, remembering the initial
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# constants.
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def watch_namespaces(namespaces)
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@watching << namespaces.map do |namespace|
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module_name = Dependencies.to_constant_name(namespace)
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original_constants = Dependencies.qualified_const_defined?(module_name) ?
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Inflector.constantize(module_name).constants(false) : []
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@stack[module_name] << original_constants
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module_name
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end
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end
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private
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def pop_modules(modules)
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modules.each { |mod| @stack[mod].pop }
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end
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end
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# An internal stack used to record which constants are loaded by any block.
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mattr_accessor :constant_watch_stack, default: WatchStack.new
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# Module includes this module.
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module ModuleConstMissing #:nodoc:
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def self.append_features(base)
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base.class_eval do
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# Emulate #exclude via an ivar
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return if defined?(@_const_missing) && @_const_missing
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@_const_missing = instance_method(:const_missing)
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remove_method(:const_missing)
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end
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super
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end
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def self.exclude_from(base)
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base.class_eval do
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define_method :const_missing, @_const_missing
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@_const_missing = nil
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end
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end
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def const_missing(const_name)
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from_mod = anonymous? ? guess_for_anonymous(const_name) : self
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Dependencies.load_missing_constant(from_mod, const_name)
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end
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# We assume that the name of the module reflects the nesting
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# (unless it can be proven that is not the case) and the path to the file
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# that defines the constant. Anonymous modules cannot follow these
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# conventions and therefore we assume that the user wants to refer to a
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# top-level constant.
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def guess_for_anonymous(const_name)
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if Object.const_defined?(const_name)
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raise NameError.new "#{const_name} cannot be autoloaded from an anonymous class or module", const_name
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else
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Object
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end
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end
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def unloadable(const_desc = self)
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super(const_desc)
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end
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end
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# Object includes this module.
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module Loadable #:nodoc:
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def self.exclude_from(base)
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base.class_eval do
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define_method(:load, Kernel.instance_method(:load))
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private :load
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end
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end
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def require_or_load(file_name)
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Dependencies.require_or_load(file_name)
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end
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# :doc:
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# Interprets a file using <tt>mechanism</tt> and marks its defined
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# constants as autoloaded. <tt>file_name</tt> can be either a string or
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# respond to <tt>to_path</tt>.
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#
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# Use this method in code that absolutely needs a certain constant to be
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# defined at that point. A typical use case is to make constant name
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# resolution deterministic for constants with the same relative name in
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# different namespaces whose evaluation would depend on load order
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# otherwise.
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def require_dependency(file_name, message = "No such file to load -- %s.rb")
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file_name = file_name.to_path if file_name.respond_to?(:to_path)
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unless file_name.is_a?(String)
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raise ArgumentError, "the file name must either be a String or implement #to_path -- you passed #{file_name.inspect}"
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end
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Dependencies.depend_on(file_name, message)
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end
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# :nodoc:
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def load_dependency(file)
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if Dependencies.load? && Dependencies.constant_watch_stack.watching?
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descs = Dependencies.constant_watch_stack.watching.flatten.uniq
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Dependencies.new_constants_in(*descs) { yield }
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else
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yield
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end
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rescue Exception => exception # errors from loading file
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exception.blame_file! file if exception.respond_to? :blame_file!
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raise
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end
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# Mark the given constant as unloadable. Unloadable constants are removed
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# each time dependencies are cleared.
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#
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# Note that marking a constant for unloading need only be done once. Setup
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# or init scripts may list each unloadable constant that may need unloading;
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# each constant will be removed for every subsequent clear, as opposed to
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# for the first clear.
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#
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# The provided constant descriptor may be a (non-anonymous) module or class,
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# or a qualified constant name as a string or symbol.
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#
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# Returns +true+ if the constant was not previously marked for unloading,
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# +false+ otherwise.
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def unloadable(const_desc)
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Dependencies.mark_for_unload const_desc
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end
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private
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def load(file, wrap = false)
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result = false
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load_dependency(file) { result = super }
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result
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end
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def require(file)
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result = false
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load_dependency(file) { result = super }
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result
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end
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end
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# Exception file-blaming.
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module Blamable #:nodoc:
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def blame_file!(file)
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(@blamed_files ||= []).unshift file
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end
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def blamed_files
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@blamed_files ||= []
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end
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def describe_blame
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return nil if blamed_files.empty?
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"This error occurred while loading the following files:\n #{blamed_files.join "\n "}"
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end
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def copy_blame!(exc)
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@blamed_files = exc.blamed_files.clone
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self
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end
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end
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def hook!
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Object.class_eval { include Loadable }
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Module.class_eval { include ModuleConstMissing }
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Exception.class_eval { include Blamable }
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end
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def unhook!
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ModuleConstMissing.exclude_from(Module)
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Loadable.exclude_from(Object)
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end
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def load?
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mechanism == :load
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end
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def depend_on(file_name, message = "No such file to load -- %s.rb")
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path = search_for_file(file_name)
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require_or_load(path || file_name)
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rescue LoadError => load_error
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if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
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load_error.message.replace(message % file_name)
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load_error.copy_blame!(load_error)
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end
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raise
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end
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def clear
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Dependencies.unload_interlock do
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loaded.clear
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loading.clear
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remove_unloadable_constants!
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end
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end
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def require_or_load(file_name, const_path = nil)
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file_name = file_name.chomp(".rb")
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expanded = File.expand_path(file_name)
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return if loaded.include?(expanded)
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Dependencies.load_interlock do
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# Maybe it got loaded while we were waiting for our lock:
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return if loaded.include?(expanded)
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# Record that we've seen this file *before* loading it to avoid an
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# infinite loop with mutual dependencies.
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loaded << expanded
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loading << expanded
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begin
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if load?
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# Enable warnings if this file has not been loaded before and
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# warnings_on_first_load is set.
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load_args = ["#{file_name}.rb"]
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load_args << const_path unless const_path.nil?
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if !warnings_on_first_load || history.include?(expanded)
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result = load_file(*load_args)
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else
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enable_warnings { result = load_file(*load_args) }
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end
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else
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result = require file_name
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end
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rescue Exception
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loaded.delete expanded
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raise
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ensure
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loading.pop
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end
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# Record history *after* loading so first load gets warnings.
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history << expanded
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result
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end
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end
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# Is the provided constant path defined?
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def qualified_const_defined?(path)
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Object.const_defined?(path, false)
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end
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# Given +path+, a filesystem path to a ruby file, return an array of
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# constant paths which would cause Dependencies to attempt to load this
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# file.
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def loadable_constants_for_path(path, bases = autoload_paths)
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path = path.chomp(".rb")
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expanded_path = File.expand_path(path)
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paths = []
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bases.each do |root|
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expanded_root = File.expand_path(root)
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next unless expanded_path.start_with?(expanded_root)
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root_size = expanded_root.size
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next if expanded_path[root_size] != ?/
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nesting = expanded_path[(root_size + 1)..-1]
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paths << nesting.camelize unless nesting.blank?
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end
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paths.uniq!
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paths
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end
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# Search for a file in autoload_paths matching the provided suffix.
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def search_for_file(path_suffix)
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path_suffix += ".rb" unless path_suffix.ends_with?(".rb")
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autoload_paths.each do |root|
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path = File.join(root, path_suffix)
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return path if File.file? path
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end
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nil # Gee, I sure wish we had first_match ;-)
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end
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# Does the provided path_suffix correspond to an autoloadable module?
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# Instead of returning a boolean, the autoload base for this module is
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# returned.
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def autoloadable_module?(path_suffix)
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autoload_paths.each do |load_path|
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return load_path if File.directory? File.join(load_path, path_suffix)
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end
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nil
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end
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def load_once_path?(path)
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# to_s works around a ruby issue where String#starts_with?(Pathname)
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# will raise a TypeError: no implicit conversion of Pathname into String
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autoload_once_paths.any? { |base| path.starts_with? base.to_s }
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end
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# Attempt to autoload the provided module name by searching for a directory
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# matching the expected path suffix. If found, the module is created and
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# assigned to +into+'s constants with the name +const_name+. Provided that
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# the directory was loaded from a reloadable base path, it is added to the
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# set of constants that are to be unloaded.
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def autoload_module!(into, const_name, qualified_name, path_suffix)
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return nil unless base_path = autoloadable_module?(path_suffix)
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mod = Module.new
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into.const_set const_name, mod
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log("constant #{qualified_name} autoloaded (module autovivified from #{File.join(base_path, path_suffix)})")
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autoloaded_constants << qualified_name unless autoload_once_paths.include?(base_path)
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autoloaded_constants.uniq!
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mod
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end
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# Load the file at the provided path. +const_paths+ is a set of qualified
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# constant names. When loading the file, Dependencies will watch for the
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# addition of these constants. Each that is defined will be marked as
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# autoloaded, and will be removed when Dependencies.clear is next called.
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#
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# If the second parameter is left off, then Dependencies will construct a
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# set of names that the file at +path+ may define. See
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# +loadable_constants_for_path+ for more details.
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def load_file(path, const_paths = loadable_constants_for_path(path))
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const_paths = [const_paths].compact unless const_paths.is_a? Array
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parent_paths = const_paths.collect { |const_path| const_path[/.*(?=::)/] || ::Object }
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result = nil
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newly_defined_paths = new_constants_in(*parent_paths) do
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result = Kernel.load path
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end
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autoloaded_constants.concat newly_defined_paths unless load_once_path?(path)
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autoloaded_constants.uniq!
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result
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end
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# Returns the constant path for the provided parent and constant name.
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def qualified_name_for(mod, name)
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mod_name = to_constant_name mod
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mod_name == "Object" ? name.to_s : "#{mod_name}::#{name}"
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end
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# Load the constant named +const_name+ which is missing from +from_mod+. If
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# it is not possible to load the constant into from_mod, try its parent
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# module using +const_missing+.
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def load_missing_constant(from_mod, const_name)
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unless qualified_const_defined?(from_mod.name) && Inflector.constantize(from_mod.name).equal?(from_mod)
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raise ArgumentError, "A copy of #{from_mod} has been removed from the module tree but is still active!"
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end
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qualified_name = qualified_name_for(from_mod, const_name)
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path_suffix = qualified_name.underscore
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file_path = search_for_file(path_suffix)
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if file_path
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expanded = File.expand_path(file_path)
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expanded.sub!(/\.rb\z/, "")
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|
|
|
if loading.include?(expanded)
|
|
raise "Circular dependency detected while autoloading constant #{qualified_name}"
|
|
else
|
|
require_or_load(expanded, qualified_name)
|
|
|
|
if from_mod.const_defined?(const_name, false)
|
|
log("constant #{qualified_name} autoloaded from #{expanded}.rb")
|
|
return from_mod.const_get(const_name)
|
|
else
|
|
raise LoadError, "Unable to autoload constant #{qualified_name}, expected #{file_path} to define it"
|
|
end
|
|
end
|
|
elsif mod = autoload_module!(from_mod, const_name, qualified_name, path_suffix)
|
|
return mod
|
|
elsif (parent = from_mod.module_parent) && parent != from_mod &&
|
|
! from_mod.module_parents.any? { |p| p.const_defined?(const_name, false) }
|
|
# 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
|
|
# Since Ruby does not pass the nesting at the point the unknown
|
|
# constant triggered the callback we cannot fully emulate constant
|
|
# name lookup and need to make a trade-off: we are going to assume
|
|
# that the nesting in the body of Foo::Bar is [Foo::Bar, Foo] even
|
|
# though it might not be. Counterexamples are
|
|
#
|
|
# class Foo::Bar
|
|
# Module.nesting # => [Foo::Bar]
|
|
# end
|
|
#
|
|
# or
|
|
#
|
|
# module M::N
|
|
# module S::T
|
|
# Module.nesting # => [S::T, M::N]
|
|
# end
|
|
# end
|
|
#
|
|
# for example.
|
|
return parent.const_missing(const_name)
|
|
rescue NameError => e
|
|
raise unless e.missing_name? qualified_name_for(parent, const_name)
|
|
end
|
|
end
|
|
|
|
name_error = NameError.new("uninitialized constant #{qualified_name}", const_name)
|
|
name_error.set_backtrace(caller.reject { |l| l.starts_with? __FILE__ })
|
|
raise name_error
|
|
end
|
|
|
|
# Remove the constants that have been autoloaded, and those that have been
|
|
# marked for unloading. Before each constant is removed a callback is sent
|
|
# to its class/module if it implements +before_remove_const+.
|
|
#
|
|
# The callback implementation should be restricted to cleaning up caches, etc.
|
|
# as the environment will be in an inconsistent state, e.g. other constants
|
|
# may have already been unloaded and not accessible.
|
|
def remove_unloadable_constants!
|
|
log("removing unloadable constants")
|
|
autoloaded_constants.each { |const| remove_constant const }
|
|
autoloaded_constants.clear
|
|
Reference.clear!
|
|
explicitly_unloadable_constants.each { |const| remove_constant const }
|
|
end
|
|
|
|
class ClassCache
|
|
def initialize
|
|
@store = Concurrent::Map.new
|
|
end
|
|
|
|
def empty?
|
|
@store.empty?
|
|
end
|
|
|
|
def key?(key)
|
|
@store.key?(key)
|
|
end
|
|
|
|
def get(key)
|
|
key = key.name if key.respond_to?(:name)
|
|
@store[key] ||= Inflector.constantize(key)
|
|
end
|
|
alias :[] :get
|
|
|
|
def safe_get(key)
|
|
key = key.name if key.respond_to?(:name)
|
|
@store[key] ||= Inflector.safe_constantize(key)
|
|
end
|
|
|
|
def store(klass)
|
|
return self unless klass.respond_to?(:name)
|
|
raise(ArgumentError, "anonymous classes cannot be cached") if klass.name.empty?
|
|
@store[klass.name] = klass
|
|
self
|
|
end
|
|
|
|
def clear!
|
|
@store.clear
|
|
end
|
|
end
|
|
|
|
Reference = ClassCache.new
|
|
|
|
# Store a reference to a class +klass+.
|
|
def reference(klass)
|
|
Reference.store klass
|
|
end
|
|
|
|
# Get the reference for class named +name+.
|
|
# Raises an exception if referenced class does not exist.
|
|
def constantize(name)
|
|
Reference.get(name)
|
|
end
|
|
|
|
# Get the reference for class named +name+ if one exists.
|
|
# Otherwise returns +nil+.
|
|
def safe_constantize(name)
|
|
Reference.safe_get(name)
|
|
end
|
|
|
|
# Determine if the given constant has been automatically loaded.
|
|
def autoloaded?(desc)
|
|
return false if desc.is_a?(Module) && desc.anonymous?
|
|
name = to_constant_name desc
|
|
return false unless qualified_const_defined?(name)
|
|
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
|
|
false
|
|
else
|
|
explicitly_unloadable_constants << name
|
|
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)
|
|
constant_watch_stack.watch_namespaces(descs)
|
|
success = false
|
|
|
|
begin
|
|
yield # Now yield to the code that is to define new constants.
|
|
success = true
|
|
ensure
|
|
new_constants = constant_watch_stack.new_constants
|
|
|
|
return new_constants if success
|
|
|
|
# Remove partially loaded constants.
|
|
new_constants.each { |c| remove_constant(c) }
|
|
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:
|
|
case desc
|
|
when String then desc.sub(/^::/, "")
|
|
when Symbol then desc.to_s
|
|
when Module
|
|
desc.name ||
|
|
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:
|
|
# Normalize ::Foo, ::Object::Foo, Object::Foo, Object::Object::Foo, etc. as Foo.
|
|
normalized = const.to_s.sub(/\A::/, "")
|
|
normalized.sub!(/\A(Object::)+/, "")
|
|
|
|
constants = normalized.split("::")
|
|
to_remove = constants.pop
|
|
|
|
# Remove the file path from the loaded list.
|
|
file_path = search_for_file(const.underscore)
|
|
if file_path
|
|
expanded = File.expand_path(file_path)
|
|
expanded.sub!(/\.rb\z/, "")
|
|
loaded.delete(expanded)
|
|
end
|
|
|
|
if constants.empty?
|
|
parent = Object
|
|
else
|
|
# This method is robust to non-reachable constants.
|
|
#
|
|
# Non-reachable constants may be passed if some of the parents were
|
|
# autoloaded and already removed. It is easier to do a sanity check
|
|
# here than require the caller to be clever. We check the parent
|
|
# rather than the very const argument because we do not want to
|
|
# trigger Kernel#autoloads, see the comment below.
|
|
parent_name = constants.join("::")
|
|
return unless qualified_const_defined?(parent_name)
|
|
parent = constantize(parent_name)
|
|
end
|
|
|
|
# In an autoloaded user.rb like this
|
|
#
|
|
# autoload :Foo, 'foo'
|
|
#
|
|
# class User < ActiveRecord::Base
|
|
# end
|
|
#
|
|
# we correctly register "Foo" as being autoloaded. But if the app does
|
|
# not use the "Foo" constant we need to be careful not to trigger
|
|
# loading "foo.rb" ourselves. While #const_defined? and #const_get? do
|
|
# require the file, #autoload? and #remove_const don't.
|
|
#
|
|
# We are going to remove the constant nonetheless ---which exists as
|
|
# far as Ruby is concerned--- because if the user removes the macro
|
|
# call from a class or module that were not autoloaded, as in the
|
|
# example above with Object, accessing to that constant must err.
|
|
unless parent.autoload?(to_remove)
|
|
begin
|
|
constantized = parent.const_get(to_remove, false)
|
|
rescue NameError
|
|
# The constant is no longer reachable, just skip it.
|
|
return
|
|
else
|
|
constantized.before_remove_const if constantized.respond_to?(:before_remove_const)
|
|
end
|
|
end
|
|
|
|
begin
|
|
parent.instance_eval { remove_const to_remove }
|
|
rescue NameError
|
|
# The constant is no longer reachable, just skip it.
|
|
end
|
|
end
|
|
|
|
def log(message)
|
|
logger.debug("autoloading: #{message}") if logger && verbose
|
|
end
|
|
end
|
|
end
|
|
|
|
ActiveSupport::Dependencies.hook!
|