Import RubyGems trunk revision 1493.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 905 insertions, 0 deletions

diff --git a/lib/rubygems/specification.rb b/lib/rubygems/specification.rb
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+++ b/lib/rubygems/specification.rb
@@ -0,0 +1,905 @@
+#--
+# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
+# All rights reserved.
+# See LICENSE.txt for permissions.
+#++
+
+require 'time'
+require 'rubygems'
+require 'rubygems/version'
+require 'rubygems/platform'
+
+# :stopdoc:
+# Time::today has been deprecated in 0.9.5 and will be removed.
+def Time.today
+  t = Time.now
+  t - ((t.to_i + t.gmt_offset) % 86400)
+end unless defined? Time.today
+# :startdoc:
+
+module Gem
+
+  # == Gem::Specification
+  #
+  # The Specification class contains the metadata for a Gem.  Typically
+  # defined in a .gemspec file or a Rakefile, and looks like this:
+  #
+  #   spec = Gem::Specification.new do |s|
+  #     s.name = 'rfoo'
+  #     s.version = '1.0'
+  #     s.summary = 'Example gem specification'
+  #     ...
+  #   end
+  #
+  # There are many <em>gemspec attributes</em>, and the best place to learn
+  # about them in the "Gemspec Reference" linked from the RubyGems wiki.
+  #
+  class Specification
+
+    # Allows deinstallation of gems with legacy platforms.
+    attr_accessor :original_platform # :nodoc:
+
+    # ------------------------- Specification version contstants.
+
+    # The the version number of a specification that does not specify one
+    # (i.e. RubyGems 0.7 or earlier).
+    NONEXISTENT_SPECIFICATION_VERSION = -1
+
+    # The specification version applied to any new Specification instances
+    # created.  This should be bumped whenever something in the spec format
+    # changes.
+    CURRENT_SPECIFICATION_VERSION = 2
+
+    # An informal list of changes to the specification.  The highest-valued
+    # key should be equal to the CURRENT_SPECIFICATION_VERSION.
+    SPECIFICATION_VERSION_HISTORY = {
+      -1 => ['(RubyGems versions up to and including 0.7 did not have versioned specifications)'],
+      1  => [
+        'Deprecated "test_suite_file" in favor of the new, but equivalent, "test_files"',
+        '"test_file=x" is a shortcut for "test_files=[x]"'
+      ],
+      2  => [
+        'Added "required_rubygems_version"',
+        'Now forward-compatible with future versions',
+      ],
+    }
+
+    # :stopdoc:
+    MARSHAL_FIELDS = { -1 => 16, 1 => 16, 2 => 16 }
+
+    now = Time.at(Time.now.to_i)
+    TODAY = now - ((now.to_i + now.gmt_offset) % 86400)
+    # :startdoc:
+
+    # ------------------------- Class variables.
+
+    # List of Specification instances.
+    @@list = []
+
+    # Optional block used to gather newly defined instances.
+    @@gather = nil
+
+    # List of attribute names: [:name, :version, ...]
+    @@required_attributes = []
+
+    # List of _all_ attributes and default values: [[:name, nil], [:bindir, 'bin'], ...]
+    @@attributes = []
+
+    @@nil_attributes = []
+    @@non_nil_attributes = [:@original_platform]
+
+    # List of array attributes
+    @@array_attributes = []
+
+    # Map of attribute names to default values.
+    @@default_value = {}
+
+    # ------------------------- Convenience class methods.
+
+    def self.attribute_names
+      @@attributes.map { |name, default| name }
+    end
+
+    def self.attribute_defaults
+      @@attributes.dup
+    end
+
+    def self.default_value(name)
+      @@default_value[name]
+    end
+
+    def self.required_attributes
+      @@required_attributes.dup
+    end
+
+    def self.required_attribute?(name)
+      @@required_attributes.include? name.to_sym
+    end
+
+    def self.array_attributes
+      @@array_attributes.dup
+    end
+
+    # ------------------------- Infrastructure class methods.
+
+    # A list of Specification instances that have been defined in this Ruby instance.
+    def self.list
+      @@list
+    end
+
+    # Used to specify the name and default value of a specification
+    # attribute.  The side effects are:
+    # * the name and default value are added to the @@attributes list
+    #   and @@default_value map
+    # * a standard _writer_ method (<tt>attribute=</tt>) is created
+    # * a non-standard _reader method (<tt>attribute</tt>) is created
+    #
+    # The reader method behaves like this:
+    #   def attribute
+    #     @attribute ||= (copy of default value)
+    #   end
+    #
+    # This allows lazy initialization of attributes to their default
+    # values. 
+    #
+    def self.attribute(name, default=nil)
+      ivar_name = "@#{name}".intern
+      if default.nil? then
+        @@nil_attributes << ivar_name
+      else
+        @@non_nil_attributes << [ivar_name, default]
+      end
+
+      @@attributes << [name, default]
+      @@default_value[name] = default
+      attr_accessor(name)
+    end
+
+    # Same as :attribute, but ensures that values assigned to the
+    # attribute are array values by applying :to_a to the value.
+    def self.array_attribute(name)
+      @@non_nil_attributes << ["@#{name}".intern, []]
+
+      @@array_attributes << name
+      @@attributes << [name, []]
+      @@default_value[name] = []
+      code = %{
+        def #{name}
+          @#{name} ||= []
+        end
+        def #{name}=(value)
+          @#{name} = Array(value)
+        end
+      }
+
+      module_eval code, __FILE__, __LINE__ - 9
+    end
+
+    # Same as attribute above, but also records this attribute as mandatory.
+    def self.required_attribute(*args)
+      @@required_attributes << args.first
+      attribute(*args)
+    end
+
+    # Sometimes we don't want the world to use a setter method for a particular attribute.
+    # +read_only+ makes it private so we can still use it internally.
+    def self.read_only(*names)
+      names.each do |name|
+        private "#{name}="
+      end
+    end
+
+    # Shortcut for creating several attributes at once (each with a default value of
+    # +nil+).
+    def self.attributes(*args)
+      args.each do |arg|
+        attribute(arg, nil)
+      end
+    end
+
+    # Some attributes require special behaviour when they are accessed.  This allows for
+    # that.
+    def self.overwrite_accessor(name, &block)
+      remove_method name
+      define_method(name, &block)
+    end
+
+    # Defines a _singular_ version of an existing _plural_ attribute
+    # (i.e. one whose value is expected to be an array).  This means
+    # just creating a helper method that takes a single value and
+    # appends it to the array.  These are created for convenience, so
+    # that in a spec, one can write 
+    #
+    #   s.require_path = 'mylib'
+    #
+    # instead of
+    #
+    #   s.require_paths = ['mylib']
+    #
+    # That above convenience is available courtesy of
+    #
+    #   attribute_alias_singular :require_path, :require_paths 
+    #
+    def self.attribute_alias_singular(singular, plural)
+      define_method("#{singular}=") { |val|
+        send("#{plural}=", [val])
+      }
+      define_method("#{singular}") { 
+        val = send("#{plural}")
+        val.nil? ? nil : val.first
+      }
+    end
+
+    # Dump only crucial instance variables.
+    #
+    # MAINTAIN ORDER!
+    def _dump(limit) # :nodoc:
+      Marshal.dump [
+        @rubygems_version,
+        @specification_version,
+        @name,
+        @version,
+        (Time === @date ? @date : Time.parse(@date.to_s)),
+        @summary,
+        @required_ruby_version,
+        @required_rubygems_version,
+        @new_platform,
+        @dependencies,
+        @rubyforge_project,
+        @email,
+        @authors,
+        @description,
+        @homepage,
+        @has_rdoc
+      ]
+    end
+
+    # Load custom marshal format, re-initializing defaults as needed
+    def self._load(str)
+      array = Marshal.load str
+
+      spec = Gem::Specification.new
+      spec.instance_variable_set :@specification_version, array[1]
+
+      current_version = CURRENT_SPECIFICATION_VERSION
+
+      field_count = MARSHAL_FIELDS[spec.specification_version]
+
+      if field_count.nil? or array.size < field_count then
+        raise TypeError, "invalid Gem::Specification format #{array.inspect}"
+      end
+
+      spec.instance_variable_set :@rubygems_version,          array[0]
+      # spec version
+      spec.instance_variable_set :@name,                      array[2]
+      spec.instance_variable_set :@version,                   array[3]
+      spec.instance_variable_set :@date,                      array[4]
+      spec.instance_variable_set :@summary,                   array[5]
+      spec.instance_variable_set :@required_ruby_version,     array[6]
+      spec.instance_variable_set :@required_rubygems_version, array[7]
+      spec.instance_variable_set :@new_platform,              array[8]
+      spec.instance_variable_set :@original_platform,         array[8]
+      spec.instance_variable_set :@platform,                  array[8].to_s
+      spec.instance_variable_set :@dependencies,              array[9]
+      spec.instance_variable_set :@rubyforge_project,         array[10]
+      spec.instance_variable_set :@email,                     array[11]
+      spec.instance_variable_set :@authors,                   array[12]
+      spec.instance_variable_set :@description,               array[13]
+      spec.instance_variable_set :@homepage,                  array[14]
+      spec.instance_variable_set :@has_rdoc,                  array[15]
+      spec.instance_variable_set :@loaded,                    false
+
+      spec
+    end
+
+    def warn_deprecated(old, new)
+      # How (if at all) to implement this?  We only want to warn when
+      # a gem is being built, I should think.
+    end
+    
+    # REQUIRED gemspec attributes ------------------------------------
+    
+    required_attribute :rubygems_version, RubyGemsVersion
+    required_attribute :specification_version, CURRENT_SPECIFICATION_VERSION
+    required_attribute :name
+    required_attribute :version
+    required_attribute :date, TODAY
+    required_attribute :summary
+    required_attribute :require_paths, ['lib']
+
+    # OPTIONAL gemspec attributes ------------------------------------
+    
+    attributes :email, :homepage, :rubyforge_project, :description
+    attributes :autorequire, :default_executable
+
+    attribute :bindir,                     'bin'
+    attribute :has_rdoc,                   false
+    attribute :required_ruby_version,      Gem::Requirement.default
+    attribute :required_rubygems_version,  Gem::Requirement.default
+    attribute :platform,                   Gem::Platform::RUBY
+
+    attribute :signing_key,            nil
+    attribute :cert_chain,             []
+    attribute :post_install_message,   nil
+
+    array_attribute :authors
+    array_attribute :files
+    array_attribute :test_files
+    array_attribute :rdoc_options
+    array_attribute :extra_rdoc_files
+    array_attribute :executables
+
+    # Array of extensions to build.  See Gem::Installer#build_extensions for
+    # valid values.
+
+    array_attribute :extensions
+    array_attribute :requirements
+    array_attribute :dependencies
+
+    read_only :dependencies
+
+    # ALIASED gemspec attributes -------------------------------------
+    
+    attribute_alias_singular :executable,   :executables
+    attribute_alias_singular :author,   :authors
+    attribute_alias_singular :require_path, :require_paths
+    attribute_alias_singular :test_file,    :test_files
+
+    # DEPRECATED gemspec attributes ----------------------------------
+    
+    def test_suite_file
+      warn_deprecated(:test_suite_file, :test_files)
+      test_files.first
+    end
+
+    def test_suite_file=(val)
+      warn_deprecated(:test_suite_file, :test_files)
+      @test_files = [] unless defined? @test_files
+      @test_files << val
+    end
+
+    # true when this gemspec has been loaded from a specifications directory.
+    # This attribute is not persisted.
+
+    attr_writer :loaded
+
+    # Path this gemspec was loaded from.  This attribute is not persisted.
+    attr_accessor :loaded_from
+
+    # Special accessor behaviours (overwriting default) --------------
+    
+    overwrite_accessor :version= do |version|
+      @version = Version.create(version)
+    end
+
+    overwrite_accessor :platform do
+      @new_platform
+    end
+
+    overwrite_accessor :platform= do |platform|
+      @original_platform = platform if @original_platform.nil?
+
+      case platform
+      when Gem::Platform::CURRENT then
+        @new_platform = Gem::Platform.local
+
+      when Gem::Platform then
+        @new_platform = platform
+
+      # legacy constants
+      when nil, Gem::Platform::RUBY then
+        @new_platform = Gem::Platform::RUBY
+      when Gem::Platform::WIN32 then
+        @new_platform = Gem::Platform::MSWIN32
+      when Gem::Platform::LINUX_586 then
+        @new_platform = Gem::Platform::X86_LINUX
+      when Gem::Platform::DARWIN then
+        @new_platform = Gem::Platform::PPC_DARWIN
+      else
+        @new_platform = platform
+      end
+
+      @platform = @new_platform.to_s
+
+      @new_platform
+    end
+
+    overwrite_accessor :required_ruby_version= do |value|
+      @required_ruby_version = Gem::Requirement.create(value)
+    end
+
+    overwrite_accessor :required_rubygems_version= do |value|
+      @required_rubygems_version = Gem::Requirement.create(value)
+    end
+
+    overwrite_accessor :date= do |date|
+      # We want to end up with a Time object with one-day resolution.
+      # This is the cleanest, most-readable, faster-than-using-Date
+      # way to do it.
+      case date
+      when String then
+        @date = Time.parse date
+      when Time then
+        @date = Time.parse date.strftime("%Y-%m-%d")
+      when Date then
+        @date = Time.parse date.to_s
+      else
+        @date = TODAY
+      end
+    end
+
+    overwrite_accessor :date do
+      self.date = nil if @date.nil?  # HACK Sets the default value for date
+      @date
+    end
+
+    overwrite_accessor :summary= do |str|
+      @summary = if str then
+                   str.strip.
+                   gsub(/(\w-)\n[ \t]*(\w)/, '\1\2').
+                   gsub(/\n[ \t]*/, " ")
+                 end
+    end
+
+    overwrite_accessor :description= do |str|
+      @description = if str then
+                       str.strip.
+                       gsub(/(\w-)\n[ \t]*(\w)/, '\1\2').
+                       gsub(/\n[ \t]*/, " ")
+                     end
+    end
+
+    overwrite_accessor :default_executable do
+      begin
+        if defined? @default_executable and @default_executable
+          result = @default_executable
+        elsif @executables and @executables.size == 1
+          result = Array(@executables).first
+        else
+          result = nil
+        end
+        result
+      rescue
+        nil
+      end
+    end
+
+    def add_bindir(executables)
+      if not defined? @executables || @executables.nil?
+        return nil
+      end
+
+      if defined? @bindir and @bindir then
+        Array(@executables).map {|e| File.join(@bindir, e) }
+      else
+        @executables
+      end
+    rescue
+      return nil
+    end
+
+    overwrite_accessor :files do
+      result = []
+      result.push(*@files) if defined?(@files)
+      result.push(*@test_files) if defined?(@test_files)
+      result.push(*(add_bindir(@executables)))
+      result.push(*@extra_rdoc_files) if defined?(@extra_rdoc_files)
+      result.push(*@extensions) if defined?(@extensions)
+      result.uniq.compact
+    end
+
+    # Files in the Gem under one of the require_paths
+    def lib_files
+      @files.select do |file|
+        require_paths.any? do |path|
+          file.index(path) == 0
+        end
+      end
+    end
+
+    overwrite_accessor :test_files do
+      # Handle the possibility that we have @test_suite_file but not
+      # @test_files.  This will happen when an old gem is loaded via
+      # YAML.
+      if defined? @test_suite_file then
+        @test_files = [@test_suite_file].flatten
+        @test_suite_file = nil
+      end
+      if defined? @test_files and @test_files then
+        @test_files
+      else
+        @test_files = []
+      end
+    end
+
+    # Predicates -----------------------------------------------------
+    
+    def loaded?; @loaded ? true : false ; end
+    def has_rdoc?; has_rdoc ? true : false ; end
+    def has_unit_tests?; not test_files.empty?; end
+    alias has_test_suite? has_unit_tests?               # (deprecated)
+    
+    # Constructors ---------------------------------------------------
+    
+    # Specification constructor.  Assigns the default values to the
+    # attributes, adds this spec to the list of loaded specs (see
+    # Specification.list), and yields itself for further initialization.
+    #
+    def initialize
+      @new_platform = nil
+      assign_defaults
+      @loaded = false
+      @@list << self
+
+      yield self if block_given?
+
+      @@gather.call(self) if @@gather
+    end
+
+    # Each attribute has a default value (possibly nil).  Here, we
+    # initialize all attributes to their default value.  This is
+    # done through the accessor methods, so special behaviours will
+    # be honored.  Furthermore, we take a _copy_ of the default so
+    # each specification instance has its own empty arrays, etc.
+    def assign_defaults
+      @@nil_attributes.each do |name|
+        instance_variable_set name, nil
+      end
+
+      @@non_nil_attributes.each do |name, default|
+        value = case default
+                when Time, Numeric, Symbol, true, false, nil then default
+                else default.dup
+                end
+
+        instance_variable_set name, value
+      end
+
+      # HACK
+      instance_variable_set :@new_platform, Gem::Platform::RUBY
+    end
+
+    # Special loader for YAML files.  When a Specification object is
+    # loaded from a YAML file, it bypasses the normal Ruby object
+    # initialization routine (#initialize).  This method makes up for
+    # that and deals with gems of different ages.
+    #
+    # 'input' can be anything that YAML.load() accepts: String or IO. 
+    #
+    def self.from_yaml(input)
+      input = normalize_yaml_input input
+      spec = YAML.load input
+
+      if spec && spec.class == FalseClass then
+        raise Gem::EndOfYAMLException
+      end
+
+      unless Gem::Specification === spec then
+        raise Gem::Exception, "YAML data doesn't evaluate to gem specification"
+      end
+
+      unless (spec.instance_variables.include? '@specification_version' or
+              spec.instance_variables.include? :@specification_version) and
+             spec.instance_variable_get :@specification_version
+        spec.instance_variable_set :@specification_version, 
+                                   NONEXISTENT_SPECIFICATION_VERSION
+      end
+
+      spec
+    end 
+
+    def self.load(filename)
+      gemspec = nil
+      fail "NESTED Specification.load calls not allowed!" if @@gather
+      @@gather = proc { |gs| gemspec = gs }
+      data = File.read(filename)
+      eval(data)
+      gemspec
+    ensure
+      @@gather = nil
+    end
+
+    # Make sure the yaml specification is properly formatted with dashes.
+    def self.normalize_yaml_input(input)
+      result = input.respond_to?(:read) ? input.read : input
+      result = "--- " + result unless result =~ /^--- /
+      result
+    end
+    
+    # Instance methods -----------------------------------------------
+    
+    # Sets the rubygems_version to Gem::RubyGemsVersion.
+    #
+    def mark_version
+      @rubygems_version = RubyGemsVersion
+    end
+
+    # Ignore unknown attributes if the 
+    def method_missing(sym, *a, &b) # :nodoc:
+      if @specification_version > CURRENT_SPECIFICATION_VERSION and
+         sym.to_s =~ /=$/ then
+        warn "ignoring #{sym} loading #{full_name}" if $DEBUG
+      else
+        super
+      end
+    end
+
+    # Adds a dependency to this Gem.  For example,
+    #
+    #   spec.add_dependency('jabber4r', '> 0.1', '<= 0.5')
+    #
+    # gem:: [String or Gem::Dependency] The Gem name/dependency.
+    # requirements:: [default=">= 0"] The version requirements.
+    #
+    def add_dependency(gem, *requirements)
+      requirements = if requirements.empty? then
+                       Gem::Requirement.default
+                     else
+                       requirements.flatten
+                     end
+
+      unless gem.respond_to?(:name) && gem.respond_to?(:version_requirements)
+        gem = Dependency.new(gem, requirements)
+      end
+
+      dependencies << gem
+    end
+    
+    # Returns the full name (name-version) of this Gem.  Platform information
+    # is included (name-version-platform) if it is specified (and not the
+    # default Ruby platform).
+    #
+    def full_name
+      if platform == Gem::Platform::RUBY or platform.nil? then
+        "#{@name}-#{@version}"
+      else
+        "#{@name}-#{@version}-#{platform}"
+      end
+    end
+
+    # The full path to the gem (install path + full name).
+    #
+    # return:: [String] the full gem path
+    #
+    def full_gem_path
+      path = File.join installation_path, 'gems', full_name
+      return path if File.directory? path
+      File.join installation_path, 'gems',
+                "#{name}-#{version}-#{@original_platform}"
+    end
+    
+    # The default (generated) file name of the gem.
+    def file_name
+      full_name + ".gem"
+    end
+    
+    # The root directory that the gem was installed into.
+    #
+    # return:: [String] the installation path
+    #
+    def installation_path
+      (File.dirname(@loaded_from).split(File::SEPARATOR)[0..-2]).
+        join(File::SEPARATOR)
+    end
+    
+    # Checks if this Specification meets the requirement of the supplied
+    # dependency.
+    # 
+    # dependency:: [Gem::Dependency] the dependency to check
+    # return:: [Boolean] true if dependency is met, otherwise false
+    #
+    def satisfies_requirement?(dependency)
+      return @name == dependency.name && 
+        dependency.version_requirements.satisfied_by?(@version)
+    end
+
+    # Comparison methods ---------------------------------------------
+
+    def sort_obj
+      [@name, @version.to_ints, @new_platform == Gem::Platform::RUBY ? -1 : 1]
+    end
+
+    def <=>(other) # :nodoc:
+      sort_obj <=> other.sort_obj
+    end
+
+    # Tests specs for equality (across all attributes).
+    def ==(other) # :nodoc:
+      self.class === other && same_attributes?(other)
+    end
+
+    alias eql? == # :nodoc:
+
+    def same_attributes?(other)
+      @@attributes.each do |name, default|
+        return false unless self.send(name) == other.send(name)
+      end
+      true
+    end
+    private :same_attributes?
+
+    def hash # :nodoc:
+      @@attributes.inject(0) { |hash_code, (name, default_value)|
+        n = self.send(name).hash
+        hash_code + n
+      }
+    end
+    
+    # Export methods (YAML and Ruby code) ----------------------------
+    
+    # Returns an array of attribute names to be used when generating a
+    # YAML representation of this object.  If an attribute still has
+    # its default value, it is omitted.
+    def to_yaml_properties
+      mark_version
+      @@attributes.map { |name, default| "@#{name}" }
+    end
+
+    def yaml_initialize(tag, vals)
+      vals.each do |ivar, val|
+        instance_variable_set "@#{ivar}", val
+      end
+
+      @original_platform = @platform # for backwards compatibility
+      self.platform = Gem::Platform.new @platform
+    end
+
+    # Returns a Ruby code representation of this specification, such that it
+    # can be eval'ed and reconstruct the same specification later.  Attributes
+    # that still have their default values are omitted.
+    def to_ruby
+      mark_version
+      result = []
+      result << "Gem::Specification.new do |s|"
+
+      result << "  s.name = #{ruby_code name}"
+      result << "  s.version = #{ruby_code version}"
+      result << ""
+      result << "  s.specification_version = #{specification_version} if s.respond_to? :specification_version="
+      result << ""
+      result << "  s.required_rubygems_version = #{ruby_code required_rubygems_version} if s.respond_to? :required_rubygems_version="
+
+      handled = [
+        :dependencies,
+        :name,
+        :required_rubygems_version,
+        :specification_version,
+        :version,
+      ]
+
+      attributes = @@attributes.sort_by { |name,| name.to_s }
+
+      attributes.each do |name, default|
+        next if handled.include? name
+        current_value = self.send(name)
+        if current_value != default or self.class.required_attribute? name then
+          result << "  s.#{name} = #{ruby_code current_value}"
+        end
+      end
+
+      result << "" unless dependencies.empty?
+
+      dependencies.each do |dep|
+        version_reqs_param = dep.requirements_list.inspect
+        result << "  s.add_dependency(%q<#{dep.name}>, #{version_reqs_param})"
+      end
+
+      result << "end"
+      result << ""
+
+      result.join "\n"
+    end
+
+    # Validation and normalization methods ---------------------------
+
+    # Checks that the specification contains all required fields, and
+    # does a very basic sanity check.
+    #
+    # Raises InvalidSpecificationException if the spec does not pass
+    # the checks..
+    def validate
+      normalize
+
+      if rubygems_version != RubyGemsVersion then
+        raise Gem::InvalidSpecificationException,
+              "expected RubyGems version #{RubyGemsVersion}, was #{rubygems_version}"
+      end
+
+      @@required_attributes.each do |symbol|
+        unless self.send symbol then
+          raise Gem::InvalidSpecificationException,
+                "missing value for attribute #{symbol}"
+        end
+      end 
+
+      if require_paths.empty? then
+        raise Gem::InvalidSpecificationException,
+              "specification must have at least one require_path"
+      end
+
+      case platform
+      when Gem::Platform, Platform::RUBY then # ok
+      else
+        raise Gem::InvalidSpecificationException,
+              "invalid platform #{platform.inspect}, see Gem::Platform"
+      end
+
+      true
+    end
+
+    # Normalize the list of files so that:
+    # * All file lists have redundancies removed.
+    # * Files referenced in the extra_rdoc_files are included in the
+    #   package file list. 
+    #
+    # Also, the summary and description are converted to a normal
+    # format. 
+    def normalize
+      if defined? @extra_rdoc_files and @extra_rdoc_files then
+        @extra_rdoc_files.uniq!
+        @files ||= []
+        @files.concat(@extra_rdoc_files)
+      end
+      @files.uniq! if @files
+    end
+
+    # Dependency methods ---------------------------------------------
+    
+    # Return a list of all gems that have a dependency on this
+    # gemspec.  The list is structured with entries that conform to:
+    #
+    #   [depending_gem, dependency, [list_of_gems_that_satisfy_dependency]]
+    #
+    # return:: [Array] [[dependent_gem, dependency, [list_of_satisfiers]]]
+    #
+    def dependent_gems
+      out = []
+      Gem.source_index.each do |name,gem|
+        gem.dependencies.each do |dep|
+          if self.satisfies_requirement?(dep) then
+            sats = []
+            find_all_satisfiers(dep) do |sat|
+              sats << sat
+            end
+            out << [gem, dep, sats]
+          end
+        end
+      end
+      out
+    end
+
+    def to_s
+      "#<Gem::Specification name=#{@name} version=#{@version}>"
+    end
+
+    private
+
+    def find_all_satisfiers(dep)
+      Gem.source_index.each do |name,gem|
+        if(gem.satisfies_requirement?(dep)) then
+          yield gem
+        end
+      end
+    end
+
+    # Return a string containing a Ruby code representation of the
+    # given object.
+    def ruby_code(obj)
+      case obj
+      when String            then '%q{' + obj + '}'
+      when Array             then obj.inspect
+      when Gem::Version      then obj.to_s.inspect
+      when Date              then '%q{' + obj.strftime('%Y-%m-%d') + '}'
+      when Time              then '%q{' + obj.strftime('%Y-%m-%d') + '}'
+      when Numeric           then obj.inspect
+      when true, false, nil  then obj.inspect
+      when Gem::Platform     then "Gem::Platform.new(#{obj.to_a.inspect})"
+      when Gem::Requirement  then "Gem::Requirement.new(#{obj.to_s.inspect})"
+      else raise Exception, "ruby_code case not handled: #{obj.class}"
+      end
+    end
+
+  end
+
+end
+