def _check_locations(self):
		"""Check if repositories location are correct and show a warning message if not"""
		for (name, r) in self.prepos.items():
			if name != 'DEFAULT':
				if r.location is None:
					writemsg(_("!!! Location not set for repository %s\n") % name, noiselevel=-1)
				else:
					if not isdir_raise_eaccess(r.location) and not portage._sync_mode:
						self.prepos_order.remove(name)
						writemsg(_("!!! Invalid Repository Location"
							" (not a dir): '%s'\n") % r.location, noiselevel=-1)

	def set_port_dirs(self, portdir, portdir_overlay):
		self.portdir = portdir
		self.portdir_overlay = portdir_overlay
		if self.portdir_overlay is None:
			self.portdir_overlay = ""

		self.overlay_profiles = []
		for ov in shlex_split(self.portdir_overlay):
			ov = normalize_path(ov)
			profiles_dir = os.path.join(ov, "profiles")
			if isdir_raise_eaccess(profiles_dir):
				self.overlay_profiles.append(profiles_dir)

		self.profile_locations = [os.path.join(portdir, "profiles")] + self.overlay_profiles
		self.profile_and_user_locations = self.profile_locations[:]
		if self._user_config:
			self.profile_and_user_locations.append(self.abs_user_config)

		self.profile_locations = tuple(self.profile_locations)
		self.profile_and_user_locations = tuple(self.profile_and_user_locations)

	def __init__(self, paths, settings):
		"""Load config from files in paths"""

		prepos = {}
		location_map = {}
		treemap = {}
		ignored_map = {}
		default_opts = {
			"EPREFIX" : settings["EPREFIX"],
			"EROOT" : settings["EROOT"],
			"PORTAGE_CONFIGROOT" : settings["PORTAGE_CONFIGROOT"],
			"ROOT" : settings["ROOT"],
		}

		if "PORTAGE_REPOSITORIES" in settings:
			portdir = ""
			portdir_overlay = ""
			# deprecated portdir_sync
			portdir_sync = ""
		else:
			portdir = settings.get("PORTDIR", "")
			portdir_overlay = settings.get("PORTDIR_OVERLAY", "")
			# deprecated portdir_sync
			portdir_sync = settings.get("SYNC", "")

		default_opts['sync-rsync-extra-opts'] = \
			settings.get("PORTAGE_RSYNC_EXTRA_OPTS", "")

		try:
			self._parse(paths, prepos, settings.local_config, default_opts)
		except ConfigParserError as e:
			writemsg(
				_("!!! Error while reading repo config file: %s\n") % e,
				noiselevel=-1)
			# The configparser state is unreliable (prone to quirky
			# exceptions) after it has thrown an error, so use empty
			# config and try to fall back to PORTDIR{,_OVERLAY}.
			prepos.clear()
			prepos['DEFAULT'] = RepoConfig('DEFAULT',
				{}, local_config=settings.local_config)
			location_map.clear()
			treemap.clear()

		default_portdir = os.path.join(os.sep,
			settings['EPREFIX'].lstrip(os.sep), 'usr', 'portage')

		# If PORTDIR_OVERLAY contains a repo with the same repo_name as
		# PORTDIR, then PORTDIR is overridden.
		portdir = self._add_repositories(portdir, portdir_overlay, prepos,
			ignored_map, settings.local_config,
			default_portdir)
		if portdir and portdir.strip():
			portdir = os.path.realpath(portdir)

		ignored_repos = tuple((repo_name, tuple(paths)) \
			for repo_name, paths in ignored_map.items())

		self.missing_repo_names = frozenset(repo.location
			for repo in prepos.values()
			if repo.location is not None and repo.missing_repo_name)

		# Do this before expanding aliases, so that location_map and
		# treemap consistently map unaliased names whenever available.
		for repo_name, repo in list(prepos.items()):
			if repo.location is None:
				if repo_name != 'DEFAULT':
					# Skip this warning for repoman (bug #474578).
					if settings.local_config and paths:
						writemsg_level("!!! %s\n" % _("Section '%s' in repos.conf is missing location attribute") %
							repo.name, level=logging.ERROR, noiselevel=-1)
					del prepos[repo_name]
					continue
			else:
				if not portage._sync_mode:
					if not isdir_raise_eaccess(repo.location):
						writemsg_level("!!! %s\n" % _("Section '%s' in repos.conf has location attribute set "
							"to nonexistent directory: '%s'") %
							(repo_name, repo.location), level=logging.ERROR, noiselevel=-1)

						# Ignore missing directory for 'gentoo' so that
						# first sync with emerge-webrsync is possible.
						if repo.name != 'gentoo':
							del prepos[repo_name]
							continue

					# After removing support for PORTDIR_OVERLAY, the following check can be:
					# if repo.missing_repo_name:
					if repo.missing_repo_name and repo.name != repo_name:
						writemsg_level("!!! %s\n" % _("Section '%s' in repos.conf refers to repository "
							"without repository name set in '%s'") %
							(repo_name, os.path.join(repo.location, REPO_NAME_LOC)), level=logging.ERROR, noiselevel=-1)
						del prepos[repo_name]
						continue

					if repo.name != repo_name:
						writemsg_level("!!! %s\n" % _("Section '%s' in repos.conf has name different "
							"from repository name '%s' set inside repository") %
							(repo_name, repo.name), level=logging.ERROR, noiselevel=-1)
						del prepos[repo_name]
						continue
#.........这里部分代码省略.........

	def _add_repositories(portdir, portdir_overlay, prepos,
		ignored_map, local_config, default_portdir):
		"""Add overlays in PORTDIR_OVERLAY as repositories"""
		overlays = []
		portdir_orig = None
		if portdir:
			portdir = normalize_path(portdir)
			portdir_orig = portdir
			overlays.append(portdir)
		try:
			port_ov = [normalize_path(i) for i in shlex_split(portdir_overlay)]
		except ValueError as e:
			#File "/usr/lib/python3.2/shlex.py", line 168, in read_token
			#	raise ValueError("No closing quotation")
			writemsg(_("!!! Invalid PORTDIR_OVERLAY:"
				" %s: %s\n") % (e, portdir_overlay), noiselevel=-1)
			port_ov = []
		overlays.extend(port_ov)
		default_repo_opts = {}
		if prepos['DEFAULT'].aliases is not None:
			default_repo_opts['aliases'] = \
				' '.join(prepos['DEFAULT'].aliases)
		if prepos['DEFAULT'].eclass_overrides is not None:
			default_repo_opts['eclass-overrides'] = \
				' '.join(prepos['DEFAULT'].eclass_overrides)
		if prepos['DEFAULT'].masters is not None:
			default_repo_opts['masters'] = \
				' '.join(prepos['DEFAULT'].masters)

		if overlays:
			# We need a copy of the original repos.conf data, since we're
			# going to modify the prepos dict and some of the RepoConfig
			# objects that we put in prepos may have to be discarded if
			# they get overridden by a repository with the same name but
			# a different location. This is common with repoman, for example,
			# when temporarily overriding an rsync repo with another copy
			# of the same repo from CVS.
			repos_conf = prepos.copy()
			#overlay priority is negative because we want them to be looked before any other repo
			base_priority = 0
			for ov in overlays:
				# Ignore missing directory for 'gentoo' so that
				# first sync with emerge-webrsync is possible.
				if isdir_raise_eaccess(ov) or \
					(base_priority == 0 and ov is portdir):
					repo_opts = default_repo_opts.copy()
					repo_opts['location'] = ov
					repo = RepoConfig(None, repo_opts, local_config=local_config)
					# repos_conf_opts contains options from repos.conf
					repos_conf_opts = repos_conf.get(repo.name)
					if repos_conf_opts is not None:
						# Selectively copy only the attributes which
						# repos.conf is allowed to override.
						for k in ('aliases', 'auto_sync',
							'clone_depth', 'eclass_overrides',
							'force', 'masters', 'priority', 'strict_misc_digests',
							'sync_depth', 'sync_hooks_only_on_change',
							'sync_openpgp_key_path',
							'sync_openpgp_key_refresh_retry_count',
							'sync_openpgp_key_refresh_retry_delay_max',
							'sync_openpgp_key_refresh_retry_delay_exp_base',
							'sync_openpgp_key_refresh_retry_delay_mult',
							'sync_openpgp_key_refresh_retry_overall_timeout',
							'sync_type', 'sync_umask', 'sync_uri', 'sync_user',
							'module_specific_options'):
							v = getattr(repos_conf_opts, k, None)
							if v is not None:
								setattr(repo, k, v)

					if repo.name in prepos:
						# Silently ignore when PORTDIR overrides the location
						# setting from the default repos.conf (bug #478544).
						old_location = prepos[repo.name].location
						if old_location is not None and \
							old_location != repo.location and \
							not (base_priority == 0 and
							old_location == default_portdir):
							ignored_map.setdefault(repo.name, []).append(old_location)
							if old_location == portdir:
								portdir = repo.location

					if repo.priority is None:
						if base_priority == 0 and ov == portdir_orig:
							# If it's the original PORTDIR setting and it's not
							# in PORTDIR_OVERLAY, then it will be assigned a
							# special priority setting later.
							pass
						else:
							repo.priority = base_priority
							base_priority += 1

					prepos[repo.name] = repo
				else:

					if not portage._sync_mode:
						writemsg(_("!!! Invalid PORTDIR_OVERLAY (not a dir): '%s'\n") % ov, noiselevel=-1)

		return portdir

	def load_profiles(self, repositories, known_repository_paths):
		known_repository_paths = set(os.path.realpath(x)
			for x in known_repository_paths)

		known_repos = []
		for x in known_repository_paths:
			try:
				layout_data = {"profile-formats":
					repositories.get_repo_for_location(x).profile_formats}
			except KeyError:
				layout_data = parse_layout_conf(x)[0]
			# force a trailing '/' for ease of doing startswith checks
			known_repos.append((x + '/', layout_data))
		known_repos = tuple(known_repos)

		if self.config_profile_path is None:
			deprecated_profile_path = os.path.join(
				self.config_root, 'etc', 'make.profile')
			self.config_profile_path = \
				os.path.join(self.config_root, PROFILE_PATH)
			if isdir_raise_eaccess(self.config_profile_path):
				self.profile_path = self.config_profile_path
				if isdir_raise_eaccess(deprecated_profile_path) and not \
					os.path.samefile(self.profile_path,
					deprecated_profile_path):
					# Don't warn if they refer to the same path, since
					# that can be used for backward compatibility with
					# old software.
					writemsg("!!! %s\n" %
						_("Found 2 make.profile dirs: "
						"using '%s', ignoring '%s'") %
						(self.profile_path, deprecated_profile_path),
						noiselevel=-1)
			else:
				self.config_profile_path = deprecated_profile_path
				if isdir_raise_eaccess(self.config_profile_path):
					self.profile_path = self.config_profile_path
				else:
					self.profile_path = None
		else:
			# NOTE: repoman may pass in an empty string
			# here, in order to create an empty profile
			# for checking dependencies of packages with
			# empty KEYWORDS.
			self.profile_path = self.config_profile_path


		# The symlink might not exist or might not be a symlink.
		self.profiles = []
		self.profiles_complex = []
		if self.profile_path:
			try:
				self._addProfile(os.path.realpath(self.profile_path),
					repositories, known_repos)
			except ParseError as e:
				if not portage._sync_disabled_warnings:
					writemsg(_("!!! Unable to parse profile: '%s'\n") % self.profile_path, noiselevel=-1)
					writemsg("!!! ParseError: %s\n" % str(e), noiselevel=-1)
				self.profiles = []
				self.profiles_complex = []

		if self._user_config and self.profiles:
			custom_prof = os.path.join(
				self.config_root, CUSTOM_PROFILE_PATH)
			if os.path.exists(custom_prof):
				self.user_profile_dir = custom_prof
				self.profiles.append(custom_prof)
				self.profiles_complex.append(
					_profile_node(custom_prof, True, True))
			del custom_prof

		self.profiles = tuple(self.profiles)
		self.profiles_complex = tuple(self.profiles_complex)

	def _check_var_directory(self, varname, var):
		if not isdir_raise_eaccess(var):
			writemsg(_("!!! Error: %s='%s' is not a directory. "
				"Please correct this.\n") % (varname, var),
				noiselevel=-1)
			raise DirectoryNotFound(var)