from __future__ import annotations
import contextlib
import dis
import marshal
import sys
from types import CodeType
from typing import Any, Literal, TypeVar
from packaging.version import Version
from . import _imp
from ._imp import PY_COMPILED, PY_FROZEN, PY_SOURCE, find_module
_T = TypeVar("_T")
__all__ = ['Require', 'find_module']
class Require:
"""A prerequisite to building or installing a distribution"""
def __init__(
self,
name,
requested_version,
module,
homepage: str = '',
attribute=None,
format=None,
) -> None:
if format is None and requested_version is not None:
format = Version
if format is not None:
requested_version = format(requested_version)
if attribute is None:
attribute = '__version__'
self.__dict__.update(locals())
del self.self
def full_name(self):
"""Return full package/distribution name, w/version"""
if self.requested_version is not None:
return f'{self.name}-{self.requested_version}'
return self.name
def version_ok(self, version):
"""Is 'version' sufficiently up-to-date?"""
return (
self.attribute is None
or self.format is None
or str(version) != "unknown"
and self.format(version) >= self.requested_version
)
def get_version(
self, paths=None, default: _T | Literal["unknown"] = "unknown"
) -> _T | Literal["unknown"] | None | Any:
"""Get version number of installed module, 'None', or 'default'
Search 'paths' for module. If not found, return 'None'. If found,
return the extracted version attribute, or 'default' if no version
attribute was specified, or the value cannot be determined without
importing the module. The version is formatted according to the
requirement's version format (if any), unless it is 'None' or the
supplied 'default'.
"""
if self.attribute is None:
try:
f, _p, _i = find_module(self.module, paths)
except ImportError:
return None
if f:
f.close()
return default
v = get_module_constant(self.module, self.attribute, default, paths)
if v is not None and v is not default and self.format is not None:
return self.format(v)
return v
def is_present(self, paths=None):
"""Return true if dependency is present on 'paths'"""
return self.get_version(paths) is not None
def is_current(self, paths=None):
"""Return true if dependency is present and up-to-date on 'paths'"""
version = self.get_version(paths)
if version is None:
return False
return self.version_ok(str(version))
def maybe_close(f):
@contextlib.contextmanager
def empty():
yield
return
if not f:
return empty()
return contextlib.closing(f)
# Some objects are not available on some platforms.
# XXX it'd be better to test assertions about bytecode instead.
if not sys.platform.startswith('java') and sys.platform != 'cli':
def get_module_constant(
module, symbol, default: _T | int = -1, paths=None
) -> _T | int | None | Any:
"""Find 'module' by searching 'paths', and extract 'symbol'
Return 'None' if 'module' does not exist on 'paths', or it does not define
'symbol'. If the module defines 'symbol' as a constant, return the
constant. Otherwise, return 'default'."""
try:
f, path, (_suffix, _mode, kind) = info = find_module(module, paths)
except ImportError:
# Module doesn't exist
return None
with maybe_close(f):
if kind == PY_COMPILED:
f.read(8) # skip magic & date
code = marshal.load(f)
elif kind == PY_FROZEN:
code = _imp.get_frozen_object(module, paths)
elif kind == PY_SOURCE:
code = compile(f.read(), path, 'exec')
else:
# Not something we can parse; we'll have to import it. :(
imported = _imp.get_module(module, paths, info)
return getattr(imported, symbol, None)
return extract_constant(code, symbol, default)
def extract_constant(
code: CodeType, symbol: str, default: _T | int = -1
) -> _T | int | None | Any:
"""Extract the constant value of 'symbol' from 'code'
If the name 'symbol' is bound to a constant value by the Python code
object 'code', return that value. If 'symbol' is bound to an expression,
return 'default'. Otherwise, return 'None'.
Return value is based on the first assignment to 'symbol'. 'symbol' must
be a global, or at least a non-"fast" local in the code block. That is,
only 'STORE_NAME' and 'STORE_GLOBAL' opcodes are checked, and 'symbol'
must be present in 'code.co_names'.
"""
if symbol not in code.co_names:
# name's not there, can't possibly be an assignment
return None
name_idx = list(code.co_names).index(symbol)
STORE_NAME = dis.opmap['STORE_NAME']
STORE_GLOBAL = dis.opmap['STORE_GLOBAL']
LOAD_CONST = dis.opmap['LOAD_CONST']
const = default
for byte_code in dis.Bytecode(code):
op = byte_code.opcode
arg = byte_code.arg
if op == LOAD_CONST:
assert arg is not None
const = code.co_consts[arg]
elif arg == name_idx and (op == STORE_NAME or op == STORE_GLOBAL):
return const
else:
const = default
return None
__all__ += ['get_module_constant', 'extract_constant']
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