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venv/lib/python2.7/site-packages/pip/_internal/configuration.py

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+"""Configuration management setup
+
+Some terminology:
+- name
+  As written in config files.
+- value
+  Value associated with a name
+- key
+  Name combined with it's section (section.name)
+- variant
+  A single word describing where the configuration key-value pair came from
+"""
+
+import locale
+import logging
+import os
+
+from pip._vendor.six.moves import configparser
+
+from pip._internal.exceptions import (
+    ConfigurationError, ConfigurationFileCouldNotBeLoaded,
+)
+from pip._internal.locations import (
+    global_config_files, legacy_config_file, new_config_file, site_config_file,
+)
+from pip._internal.utils.misc import ensure_dir, enum
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, Dict, Iterable, List, NewType, Optional, Tuple
+    )
+
+    RawConfigParser = configparser.RawConfigParser  # Shorthand
+    Kind = NewType("Kind", str)
+
+logger = logging.getLogger(__name__)
+
+
+# NOTE: Maybe use the optionx attribute to normalize keynames.
+def _normalize_name(name):
+    # type: (str) -> str
+    """Make a name consistent regardless of source (environment or file)
+    """
+    name = name.lower().replace('_', '-')
+    if name.startswith('--'):
+        name = name[2:]  # only prefer long opts
+    return name
+
+
+def _disassemble_key(name):
+    # type: (str) -> List[str]
+    return name.split(".", 1)
+
+
+# The kinds of configurations there are.
+kinds = enum(
+    USER="user",        # User Specific
+    GLOBAL="global",    # System Wide
+    SITE="site",        # [Virtual] Environment Specific
+    ENV="env",          # from PIP_CONFIG_FILE
+    ENV_VAR="env-var",  # from Environment Variables
+)
+
+
+class Configuration(object):
+    """Handles management of configuration.
+
+    Provides an interface to accessing and managing configuration files.
+
+    This class converts provides an API that takes "section.key-name" style
+    keys and stores the value associated with it as "key-name" under the
+    section "section".
+
+    This allows for a clean interface wherein the both the section and the
+    key-name are preserved in an easy to manage form in the configuration files
+    and the data stored is also nice.
+    """
+
+    def __init__(self, isolated, load_only=None):
+        # type: (bool, Kind) -> None
+        super(Configuration, self).__init__()
+
+        _valid_load_only = [kinds.USER, kinds.GLOBAL, kinds.SITE, None]
+        if load_only not in _valid_load_only:
+            raise ConfigurationError(
+                "Got invalid value for load_only - should be one of {}".format(
+                    ", ".join(map(repr, _valid_load_only[:-1]))
+                )
+            )
+        self.isolated = isolated  # type: bool
+        self.load_only = load_only  # type: Optional[Kind]
+
+        # The order here determines the override order.
+        self._override_order = [
+            kinds.GLOBAL, kinds.USER, kinds.SITE, kinds.ENV, kinds.ENV_VAR
+        ]
+
+        self._ignore_env_names = ["version", "help"]
+
+        # Because we keep track of where we got the data from
+        self._parsers = {
+            variant: [] for variant in self._override_order
+        }  # type: Dict[Kind, List[Tuple[str, RawConfigParser]]]
+        self._config = {
+            variant: {} for variant in self._override_order
+        }  # type: Dict[Kind, Dict[str, Any]]
+        self._modified_parsers = []  # type: List[Tuple[str, RawConfigParser]]
+
+    def load(self):
+        # type: () -> None
+        """Loads configuration from configuration files and environment
+        """
+        self._load_config_files()
+        if not self.isolated:
+            self._load_environment_vars()
+
+    def get_file_to_edit(self):
+        # type: () -> Optional[str]
+        """Returns the file with highest priority in configuration
+        """
+        assert self.load_only is not None, \
+            "Need to be specified a file to be editing"
+
+        try:
+            return self._get_parser_to_modify()[0]
+        except IndexError:
+            return None
+
+    def items(self):
+        # type: () -> Iterable[Tuple[str, Any]]
+        """Returns key-value pairs like dict.items() representing the loaded
+        configuration
+        """
+        return self._dictionary.items()
+
+    def get_value(self, key):
+        # type: (str) -> Any
+        """Get a value from the configuration.
+        """
+        try:
+            return self._dictionary[key]
+        except KeyError:
+            raise ConfigurationError("No such key - {}".format(key))
+
+    def set_value(self, key, value):
+        # type: (str, Any) -> None
+        """Modify a value in the configuration.
+        """
+        self._ensure_have_load_only()
+
+        fname, parser = self._get_parser_to_modify()
+
+        if parser is not None:
+            section, name = _disassemble_key(key)
+
+            # Modify the parser and the configuration
+            if not parser.has_section(section):
+                parser.add_section(section)
+            parser.set(section, name, value)
+
+        self._config[self.load_only][key] = value
+        self._mark_as_modified(fname, parser)
+
+    def unset_value(self, key):
+        # type: (str) -> None
+        """Unset a value in the configuration.
+        """
+        self._ensure_have_load_only()
+
+        if key not in self._config[self.load_only]:
+            raise ConfigurationError("No such key - {}".format(key))
+
+        fname, parser = self._get_parser_to_modify()
+
+        if parser is not None:
+            section, name = _disassemble_key(key)
+
+            # Remove the key in the parser
+            modified_something = False
+            if parser.has_section(section):
+                # Returns whether the option was removed or not
+                modified_something = parser.remove_option(section, name)
+
+            if modified_something:
+                # name removed from parser, section may now be empty
+                section_iter = iter(parser.items(section))
+                try:
+                    val = next(section_iter)
+                except StopIteration:
+                    val = None
+
+                if val is None:
+                    parser.remove_section(section)
+
+                self._mark_as_modified(fname, parser)
+            else:
+                raise ConfigurationError(
+                    "Fatal Internal error [id=1]. Please report as a bug."
+                )
+
+        del self._config[self.load_only][key]
+
+    def save(self):
+        # type: () -> None
+        """Save the current in-memory state.
+        """
+        self._ensure_have_load_only()
+
+        for fname, parser in self._modified_parsers:
+            logger.info("Writing to %s", fname)
+
+            # Ensure directory exists.
+            ensure_dir(os.path.dirname(fname))
+
+            with open(fname, "w") as f:
+                parser.write(f)
+
+    #
+    # Private routines
+    #
+
+    def _ensure_have_load_only(self):
+        # type: () -> None
+        if self.load_only is None:
+            raise ConfigurationError("Needed a specific file to be modifying.")
+        logger.debug("Will be working with %s variant only", self.load_only)
+
+    @property
+    def _dictionary(self):
+        # type: () -> Dict[str, Any]
+        """A dictionary representing the loaded configuration.
+        """
+        # NOTE: Dictionaries are not populated if not loaded. So, conditionals
+        #       are not needed here.
+        retval = {}
+
+        for variant in self._override_order:
+            retval.update(self._config[variant])
+
+        return retval
+
+    def _load_config_files(self):
+        # type: () -> None
+        """Loads configuration from configuration files
+        """
+        config_files = dict(self._iter_config_files())
+        if config_files[kinds.ENV][0:1] == [os.devnull]:
+            logger.debug(
+                "Skipping loading configuration files due to "
+                "environment's PIP_CONFIG_FILE being os.devnull"
+            )
+            return
+
+        for variant, files in config_files.items():
+            for fname in files:
+                # If there's specific variant set in `load_only`, load only
+                # that variant, not the others.
+                if self.load_only is not None and variant != self.load_only:
+                    logger.debug(
+                        "Skipping file '%s' (variant: %s)", fname, variant
+                    )
+                    continue
+
+                parser = self._load_file(variant, fname)
+
+                # Keeping track of the parsers used
+                self._parsers[variant].append((fname, parser))
+
+    def _load_file(self, variant, fname):
+        # type: (Kind, str) -> RawConfigParser
+        logger.debug("For variant '%s', will try loading '%s'", variant, fname)
+        parser = self._construct_parser(fname)
+
+        for section in parser.sections():
+            items = parser.items(section)
+            self._config[variant].update(self._normalized_keys(section, items))
+
+        return parser
+
+    def _construct_parser(self, fname):
+        # type: (str) -> RawConfigParser
+        parser = configparser.RawConfigParser()
+        # If there is no such file, don't bother reading it but create the
+        # parser anyway, to hold the data.
+        # Doing this is useful when modifying and saving files, where we don't
+        # need to construct a parser.
+        if os.path.exists(fname):
+            try:
+                parser.read(fname)
+            except UnicodeDecodeError:
+                # See https://github.com/pypa/pip/issues/4963
+                raise ConfigurationFileCouldNotBeLoaded(
+                    reason="contains invalid {} characters".format(
+                        locale.getpreferredencoding(False)
+                    ),
+                    fname=fname,
+                )
+            except configparser.Error as error:
+                # See https://github.com/pypa/pip/issues/4893
+                raise ConfigurationFileCouldNotBeLoaded(error=error)
+        return parser
+
+    def _load_environment_vars(self):
+        # type: () -> None
+        """Loads configuration from environment variables
+        """
+        self._config[kinds.ENV_VAR].update(
+            self._normalized_keys(":env:", self._get_environ_vars())
+        )
+
+    def _normalized_keys(self, section, items):
+        # type: (str, Iterable[Tuple[str, Any]]) -> Dict[str, Any]
+        """Normalizes items to construct a dictionary with normalized keys.
+
+        This routine is where the names become keys and are made the same
+        regardless of source - configuration files or environment.
+        """
+        normalized = {}
+        for name, val in items:
+            key = section + "." + _normalize_name(name)
+            normalized[key] = val
+        return normalized
+
+    def _get_environ_vars(self):
+        # type: () -> Iterable[Tuple[str, str]]
+        """Returns a generator with all environmental vars with prefix PIP_"""
+        for key, val in os.environ.items():
+            should_be_yielded = (
+                key.startswith("PIP_") and
+                key[4:].lower() not in self._ignore_env_names
+            )
+            if should_be_yielded:
+                yield key[4:].lower(), val
+
+    # XXX: This is patched in the tests.
+    def _iter_config_files(self):
+        # type: () -> Iterable[Tuple[Kind, List[str]]]
+        """Yields variant and configuration files associated with it.
+
+        This should be treated like items of a dictionary.
+        """
+        # SMELL: Move the conditions out of this function
+
+        # environment variables have the lowest priority
+        config_file = os.environ.get('PIP_CONFIG_FILE', None)
+        if config_file is not None:
+            yield kinds.ENV, [config_file]
+        else:
+            yield kinds.ENV, []
+
+        # at the base we have any global configuration
+        yield kinds.GLOBAL, list(global_config_files)
+
+        # per-user configuration next
+        should_load_user_config = not self.isolated and not (
+            config_file and os.path.exists(config_file)
+        )
+        if should_load_user_config:
+            # The legacy config file is overridden by the new config file
+            yield kinds.USER, [legacy_config_file, new_config_file]
+
+        # finally virtualenv configuration first trumping others
+        yield kinds.SITE, [site_config_file]
+
+    def _get_parser_to_modify(self):
+        # type: () -> Tuple[str, RawConfigParser]
+        # Determine which parser to modify
+        parsers = self._parsers[self.load_only]
+        if not parsers:
+            # This should not happen if everything works correctly.
+            raise ConfigurationError(
+                "Fatal Internal error [id=2]. Please report as a bug."
+            )
+
+        # Use the highest priority parser.
+        return parsers[-1]
+
+    # XXX: This is patched in the tests.
+    def _mark_as_modified(self, fname, parser):
+        # type: (str, RawConfigParser) -> None
+        file_parser_tuple = (fname, parser)
+        if file_parser_tuple not in self._modified_parsers:
+            self._modified_parsers.append(file_parser_tuple)