Redmine

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/module/qualified_const'

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 autoload_once_paths.

    mattr_accessor :autoload_paths

    self.autoload_paths = []

    # The set of directories from which automatically loaded constants are loaded

    # only once. All directories in this set must also be present in +autoload_paths+.

    mattr_accessor :autoload_once_paths

    self.autoload_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

    # The WatchStack keeps a stack of the modules being watched as files are loaded.

    # If a file in the process of being loaded (parent.rb) triggers the load of

    # another file (child.rb) the stack will ensure that child.rb handles the new

    # constants.

    #

    # If child.rb is being autoloaded, its constants will be added to

    # autoloaded_constants. If it was being `require`d, they will be discarded.

    #

    # This is handled by walking back up the watch stack and adding the constants

    # found by child.rb to the list of original constants in parent.rb

    class WatchStack

      include Enumerable

      # @watching is a stack of lists of constants being watched. For instance,

      # if parent.rb is autoloaded, the stack will look like [[Object]]. If parent.rb

      # then requires namespace/child.rb, the stack will look like [[Object], [Namespace]].

      def initialize

        @watching = []

        @stack = Hash.new { |h,k| h[k] = [] }

      end

      def each(&block)

        @stack.each(&block)

      end

      def watching?

        !@watching.empty?

      end

      # return a list of new constants found since the last call to watch_namespaces

      def new_constants

        constants = []

        # Grab the list of namespaces that we're looking for new constants under

        @watching.last.each do |namespace|

          # Retrieve the constants that were present under the namespace when watch_namespaces

          # was originally called

          original_constants = @stack[namespace].last

          mod = Inflector.constantize(namespace) if Dependencies.qualified_const_defined?(namespace)

          next unless mod.is_a?(Module)

          # Get a list of the constants that were added

          new_constants = mod.local_constant_names - original_constants

          # self[namespace] returns an Array of the constants that are being evaluated

          # for that namespace. For instance, if parent.rb requires child.rb, the first

          # element of self[Object] will be an Array of the constants that were present

          # before parent.rb was required. The second element will be an Array of the

          # constants that were present before child.rb was required.

          @stack[namespace].each do |namespace_constants|

            namespace_constants.concat(new_constants)

          end

          # Normalize the list of new constants, and add them to the list we will return

          new_constants.each do |suffix|

            constants << ([namespace, suffix] - ["Object"]).join("::")

          end

        end

        constants

      ensure

        # A call to new_constants is always called after a call to watch_namespaces

        pop_modules(@watching.pop)

      end

      # Add a set of modules to the watch stack, remembering the initial constants

      def watch_namespaces(namespaces)

        watching = []

        namespaces.map do |namespace|

          module_name = Dependencies.to_constant_name(namespace)

          original_constants = Dependencies.qualified_const_defined?(module_name) ?

            Inflector.constantize(module_name).local_constant_names : []

          watching << module_name

          @stack[module_name] << original_constants

        end

        @watching << watching

      end

      private

      def pop_modules(modules)

        modules.each { |mod| @stack[mod].pop }

      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"

        unless 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? && ActiveSupport::Dependencies.constant_watch_stack.watching?

          Dependencies.new_constants_in(Object) { yield }

        else

          yield

        end

      rescue Exception => exception  # errors from loading file

        exception.blame_file! file

        raise

      end

      def load(file, wrap = false)

        result = false

        load_dependency(file) { result = super }

        result

      end

      def require(file)

        result = false

        load_dependency(file) { result = super }

        result

      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 if 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?

    if Module.method(:const_defined?).arity == 1

      def qualified_const_defined?(path)

        Object.qualified_const_defined?(path.sub(/^::/, ''))

      end

    else

      def qualified_const_defined?(path)

        Object.qualified_const_defined?(path.sub(/^::/, ''), false)

      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 = autoload_paths)

      path = $1 if path =~ /\A(.*)\.rb\Z/

      expanded_path = File.expand_path(path)

      paths = []

      bases.each 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?

        paths << nesting.camelize

      end

      paths.uniq!

      paths

    end

    # Search for a file in autoload_paths matching the provided suffix.

    def search_for_file(path_suffix)

      path_suffix = path_suffix.sub(/(\.rb)?$/, ".rb")

      autoload_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)

      autoload_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)

      # to_s works around a ruby1.9 issue where #starts_with?(Pathname) will always return false

      autoload_once_paths.any? { |base| path.starts_with? base.to_s }

    end

    # Attempt to autoload the provided module name by searching for a directory

    # matching the expected 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 autoload_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 NameError, "#{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

      file_path = search_for_file(path_suffix)

      if file_path && ! loaded.include?(File.expand_path(file_path).sub(/\.rb\z/, '')) # 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)

        end

      end

      raise NameError,

            "uninitialized constant #{qualified_name}",

            caller.reject {|l| l.starts_with? __FILE__ }

    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!

      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 = Hash.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] || begin

          klass = Inflector.safe_constantize(key)

          @store[key] = klass

        end

      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)

      # 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)

      constant_watch_stack.watch_namespaces(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

        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 []

    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.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}"

      constantized = constantize(const)

      constantized.before_remove_const if constantized.respond_to?(:before_remove_const)

      parent.instance_eval { remove_const to_remove }

      return true

    end

    protected

      def log_call(*args)

        if 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)

        logger.debug "Dependencies: #{msg}" if log_activity?

      end

      def log_activity?

        logger && log_activity

      end

  end

end

ActiveSupport::Dependencies.hook!