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import logging
import os
import sys
import sysconfig
import typing
from pip._internal.exceptions import InvalidSchemeCombination, UserInstallationInvalid
from pip._internal.models.scheme import SCHEME_KEYS, Scheme
from pip._internal.utils.virtualenv import running_under_virtualenv
from .base import change_root, get_major_minor_version, is_osx_framework
logger = logging.getLogger(__name__)
# Notes on _infer_* functions.
# Unfortunately ``get_default_scheme()`` didn't exist before 3.10, so there's no
# way to ask things like "what is the '_prefix' scheme on this platform". These
# functions try to answer that with some heuristics while accounting for ad-hoc
# platforms not covered by CPython's default sysconfig implementation. If the
# ad-hoc implementation does not fully implement sysconfig, we'll fall back to
# a POSIX scheme.
_AVAILABLE_SCHEMES = set(sysconfig.get_scheme_names())
_PREFERRED_SCHEME_API = getattr(sysconfig, "get_preferred_scheme", None)
def _should_use_osx_framework_prefix() -> bool:
"""Check for Apple's ``osx_framework_library`` scheme.
Python distributed by Apple's Command Line Tools has this special scheme
that's used when:
* This is a framework build.
* We are installing into the system prefix.
This does not account for ``pip install --prefix`` (also means we're not
installing to the system prefix), which should use ``posix_prefix``, but
logic here means ``_infer_prefix()`` outputs ``osx_framework_library``. But
since ``prefix`` is not available for ``sysconfig.get_default_scheme()``,
which is the stdlib replacement for ``_infer_prefix()``, presumably Apple
wouldn't be able to magically switch between ``osx_framework_library`` and
``posix_prefix``. ``_infer_prefix()`` returning ``osx_framework_library``
means its behavior is consistent whether we use the stdlib implementation
or our own, and we deal with this special case in ``get_scheme()`` instead.
"""
return (
"osx_framework_library" in _AVAILABLE_SCHEMES
and not running_under_virtualenv()
and is_osx_framework()
)
def _infer_prefix() -> str:
"""Try to find a prefix scheme for the current platform.
This tries:
* A special ``osx_framework_library`` for Python distributed by Apple's
Command Line Tools, when not running in a virtual environment.
* Implementation + OS, used by PyPy on Windows (``pypy_nt``).
* Implementation without OS, used by PyPy on POSIX (``pypy``).
* OS + "prefix", used by CPython on POSIX (``posix_prefix``).
* Just the OS name, used by CPython on Windows (``nt``).
If none of the above works, fall back to ``posix_prefix``.
"""
if _PREFERRED_SCHEME_API:
return _PREFERRED_SCHEME_API("prefix")
if _should_use_osx_framework_prefix():
return "osx_framework_library"
implementation_suffixed = f"{sys.implementation.name}_{os.name}"
if implementation_suffixed in _AVAILABLE_SCHEMES:
return implementation_suffixed
if sys.implementation.name in _AVAILABLE_SCHEMES:
return sys.implementation.name
suffixed = f"{os.name}_prefix"
if suffixed in _AVAILABLE_SCHEMES:
return suffixed
if os.name in _AVAILABLE_SCHEMES: # On Windows, prefx is just called "nt".
return os.name
return "posix_prefix"
def _infer_user() -> str:
"""Try to find a user scheme for the current platform."""
if _PREFERRED_SCHEME_API:
return _PREFERRED_SCHEME_API("user")
if is_osx_framework() and not running_under_virtualenv():
suffixed = "osx_framework_user"
else:
suffixed = f"{os.name}_user"
if suffixed in _AVAILABLE_SCHEMES:
return suffixed
if "posix_user" not in _AVAILABLE_SCHEMES: # User scheme unavailable.
raise UserInstallationInvalid()
return "posix_user"
def _infer_home() -> str:
"""Try to find a home for the current platform."""
if _PREFERRED_SCHEME_API:
return _PREFERRED_SCHEME_API("home")
suffixed = f"{os.name}_home"
if suffixed in _AVAILABLE_SCHEMES:
return suffixed
return "posix_home"
# Update these keys if the user sets a custom home.
_HOME_KEYS = [
"installed_base",
"base",
"installed_platbase",
"platbase",
"prefix",
"exec_prefix",
]
if sysconfig.get_config_var("userbase") is not None:
_HOME_KEYS.append("userbase")
def get_scheme(
dist_name: str,
user: bool = False,
home: typing.Optional[str] = None,
root: typing.Optional[str] = None,
isolated: bool = False,
prefix: typing.Optional[str] = None,
) -> Scheme:
"""
Get the "scheme" corresponding to the input parameters.
:param dist_name: the name of the package to retrieve the scheme for, used
in the headers scheme path
:param user: indicates to use the "user" scheme
:param home: indicates to use the "home" scheme
:param root: root under which other directories are re-based
:param isolated: ignored, but kept for distutils compatibility (where
this controls whether the user-site pydistutils.cfg is honored)
:param prefix: indicates to use the "prefix" scheme and provides the
base directory for the same
"""
if user and prefix:
raise InvalidSchemeCombination("--user", "--prefix")
if home and prefix:
raise InvalidSchemeCombination("--home", "--prefix")
if home is not None:
scheme_name = _infer_home()
elif user:
scheme_name = _infer_user()
else:
scheme_name = _infer_prefix()
# Special case: When installing into a custom prefix, use posix_prefix
# instead of osx_framework_library. See _should_use_osx_framework_prefix()
# docstring for details.
if prefix is not None and scheme_name == "osx_framework_library":
scheme_name = "posix_prefix"
if home is not None:
variables = {k: home for k in _HOME_KEYS}
elif prefix is not None:
variables = {k: prefix for k in _HOME_KEYS}
else:
variables = {}
paths = sysconfig.get_paths(scheme=scheme_name, vars=variables)
# Logic here is very arbitrary, we're doing it for compatibility, don't ask.
# 1. Pip historically uses a special header path in virtual environments.
# 2. If the distribution name is not known, distutils uses 'UNKNOWN'. We
# only do the same when not running in a virtual environment because
# pip's historical header path logic (see point 1) did not do this.
if running_under_virtualenv():
if user:
base = variables.get("userbase", sys.prefix)
else:
base = variables.get("base", sys.prefix)
python_xy = f"python{get_major_minor_version()}"
paths["include"] = os.path.join(base, "include", "site", python_xy)
elif not dist_name:
dist_name = "UNKNOWN"
scheme = Scheme(
platlib=paths["platlib"],
purelib=paths["purelib"],
headers=os.path.join(paths["include"], dist_name),
scripts=paths["scripts"],
data=paths["data"],
)
if root is not None:
converted_keys = {}
for key in SCHEME_KEYS:
converted_keys[key] = change_root(root, getattr(scheme, key))
scheme = Scheme(**converted_keys)
return scheme
def get_bin_prefix() -> str:
# Forcing to use /usr/local/bin for standard macOS framework installs.
if sys.platform[:6] == "darwin" and sys.prefix[:16] == "/System/Library/":
return "/usr/local/bin"
return sysconfig.get_paths()["scripts"]
def get_purelib() -> str:
return sysconfig.get_paths()["purelib"]
def get_platlib() -> str:
return sysconfig.get_paths()["platlib"]
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