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stbi/Lib/site-packages/django/conf/__init__.py

+"""
+Settings and configuration for Django.
+
+Read values from the module specified by the DJANGO_SETTINGS_MODULE environment
+variable, and then from django.conf.global_settings; see the global_settings.py
+for a list of all possible variables.
+"""
+
+import importlib
+import os
+import time
+import traceback
+import warnings
+from pathlib import Path
+
+import django
+from django.conf import global_settings
+from django.core.exceptions import ImproperlyConfigured
+from django.utils.deprecation import RemovedInDjango31Warning
+from django.utils.functional import LazyObject, empty
+
+ENVIRONMENT_VARIABLE = "DJANGO_SETTINGS_MODULE"
+
+FILE_CHARSET_DEPRECATED_MSG = (
+    'The FILE_CHARSET setting is deprecated. Starting with Django 3.1, all '
+    'files read from disk must be UTF-8 encoded.'
+)
+
+
+class SettingsReference(str):
+    """
+    String subclass which references a current settings value. It's treated as
+    the value in memory but serializes to a settings.NAME attribute reference.
+    """
+    def __new__(self, value, setting_name):
+        return str.__new__(self, value)
+
+    def __init__(self, value, setting_name):
+        self.setting_name = setting_name
+
+
+class LazySettings(LazyObject):
+    """
+    A lazy proxy for either global Django settings or a custom settings object.
+    The user can manually configure settings prior to using them. Otherwise,
+    Django uses the settings module pointed to by DJANGO_SETTINGS_MODULE.
+    """
+    def _setup(self, name=None):
+        """
+        Load the settings module pointed to by the environment variable. This
+        is used the first time settings are needed, if the user hasn't
+        configured settings manually.
+        """
+        settings_module = os.environ.get(ENVIRONMENT_VARIABLE)
+        if not settings_module:
+            desc = ("setting %s" % name) if name else "settings"
+            raise ImproperlyConfigured(
+                "Requested %s, but settings are not configured. "
+                "You must either define the environment variable %s "
+                "or call settings.configure() before accessing settings."
+                % (desc, ENVIRONMENT_VARIABLE))
+
+        self._wrapped = Settings(settings_module)
+
+    def __repr__(self):
+        # Hardcode the class name as otherwise it yields 'Settings'.
+        if self._wrapped is empty:
+            return '<LazySettings [Unevaluated]>'
+        return '<LazySettings "%(settings_module)s">' % {
+            'settings_module': self._wrapped.SETTINGS_MODULE,
+        }
+
+    def __getattr__(self, name):
+        """Return the value of a setting and cache it in self.__dict__."""
+        if self._wrapped is empty:
+            self._setup(name)
+        val = getattr(self._wrapped, name)
+        self.__dict__[name] = val
+        return val
+
+    def __setattr__(self, name, value):
+        """
+        Set the value of setting. Clear all cached values if _wrapped changes
+        (@override_settings does this) or clear single values when set.
+        """
+        if name == '_wrapped':
+            self.__dict__.clear()
+        else:
+            self.__dict__.pop(name, None)
+        super().__setattr__(name, value)
+
+    def __delattr__(self, name):
+        """Delete a setting and clear it from cache if needed."""
+        super().__delattr__(name)
+        self.__dict__.pop(name, None)
+
+    def configure(self, default_settings=global_settings, **options):
+        """
+        Called to manually configure the settings. The 'default_settings'
+        parameter sets where to retrieve any unspecified values from (its
+        argument must support attribute access (__getattr__)).
+        """
+        if self._wrapped is not empty:
+            raise RuntimeError('Settings already configured.')
+        holder = UserSettingsHolder(default_settings)
+        for name, value in options.items():
+            if not name.isupper():
+                raise TypeError('Setting %r must be uppercase.' % name)
+            setattr(holder, name, value)
+        self._wrapped = holder
+
+    @property
+    def configured(self):
+        """Return True if the settings have already been configured."""
+        return self._wrapped is not empty
+
+    @property
+    def FILE_CHARSET(self):
+        stack = traceback.extract_stack()
+        # Show a warning if the setting is used outside of Django.
+        # Stack index: -1 this line, -2 the caller.
+        filename, _line_number, _function_name, _text = stack[-2]
+        if not filename.startswith(os.path.dirname(django.__file__)):
+            warnings.warn(
+                FILE_CHARSET_DEPRECATED_MSG,
+                RemovedInDjango31Warning,
+                stacklevel=2,
+            )
+        return self.__getattr__('FILE_CHARSET')
+
+
+class Settings:
+    def __init__(self, settings_module):
+        # update this dict from global settings (but only for ALL_CAPS settings)
+        for setting in dir(global_settings):
+            if setting.isupper():
+                setattr(self, setting, getattr(global_settings, setting))
+
+        # store the settings module in case someone later cares
+        self.SETTINGS_MODULE = settings_module
+
+        mod = importlib.import_module(self.SETTINGS_MODULE)
+
+        tuple_settings = (
+            "INSTALLED_APPS",
+            "TEMPLATE_DIRS",
+            "LOCALE_PATHS",
+        )
+        self._explicit_settings = set()
+        for setting in dir(mod):
+            if setting.isupper():
+                setting_value = getattr(mod, setting)
+
+                if (setting in tuple_settings and
+                        not isinstance(setting_value, (list, tuple))):
+                    raise ImproperlyConfigured("The %s setting must be a list or a tuple. " % setting)
+                setattr(self, setting, setting_value)
+                self._explicit_settings.add(setting)
+
+        if not self.SECRET_KEY:
+            raise ImproperlyConfigured("The SECRET_KEY setting must not be empty.")
+
+        if self.is_overridden('FILE_CHARSET'):
+            warnings.warn(FILE_CHARSET_DEPRECATED_MSG, RemovedInDjango31Warning)
+
+        if hasattr(time, 'tzset') and self.TIME_ZONE:
+            # When we can, attempt to validate the timezone. If we can't find
+            # this file, no check happens and it's harmless.
+            zoneinfo_root = Path('/usr/share/zoneinfo')
+            zone_info_file = zoneinfo_root.joinpath(*self.TIME_ZONE.split('/'))
+            if zoneinfo_root.exists() and not zone_info_file.exists():
+                raise ValueError("Incorrect timezone setting: %s" % self.TIME_ZONE)
+            # Move the time zone info into os.environ. See ticket #2315 for why
+            # we don't do this unconditionally (breaks Windows).
+            os.environ['TZ'] = self.TIME_ZONE
+            time.tzset()
+
+    def is_overridden(self, setting):
+        return setting in self._explicit_settings
+
+    def __repr__(self):
+        return '<%(cls)s "%(settings_module)s">' % {
+            'cls': self.__class__.__name__,
+            'settings_module': self.SETTINGS_MODULE,
+        }
+
+
+class UserSettingsHolder:
+    """Holder for user configured settings."""
+    # SETTINGS_MODULE doesn't make much sense in the manually configured
+    # (standalone) case.
+    SETTINGS_MODULE = None
+
+    def __init__(self, default_settings):
+        """
+        Requests for configuration variables not in this class are satisfied
+        from the module specified in default_settings (if possible).
+        """
+        self.__dict__['_deleted'] = set()
+        self.default_settings = default_settings
+
+    def __getattr__(self, name):
+        if not name.isupper() or name in self._deleted:
+            raise AttributeError
+        return getattr(self.default_settings, name)
+
+    def __setattr__(self, name, value):
+        self._deleted.discard(name)
+        if name == 'FILE_CHARSET':
+            warnings.warn(FILE_CHARSET_DEPRECATED_MSG, RemovedInDjango31Warning)
+        super().__setattr__(name, value)
+
+    def __delattr__(self, name):
+        self._deleted.add(name)
+        if hasattr(self, name):
+            super().__delattr__(name)
+
+    def __dir__(self):
+        return sorted(
+            s for s in [*self.__dict__, *dir(self.default_settings)]
+            if s not in self._deleted
+        )
+
+    def is_overridden(self, setting):
+        deleted = (setting in self._deleted)
+        set_locally = (setting in self.__dict__)
+        set_on_default = getattr(self.default_settings, 'is_overridden', lambda s: False)(setting)
+        return deleted or set_locally or set_on_default
+
+    def __repr__(self):
+        return '<%(cls)s>' % {
+            'cls': self.__class__.__name__,
+        }
+
+
+settings = LazySettings()