--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/setuptools/depends.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,176 @@
+import sys
+import marshal
+import contextlib
+from distutils.version import StrictVersion
+
+from .py33compat import Bytecode
+
+from .py27compat import find_module, PY_COMPILED, PY_FROZEN, PY_SOURCE
+from . import py27compat
+
+
+__all__ = [
+    'Require', 'find_module', 'get_module_constant', 'extract_constant'
+]
+
+
+class Require:
+    """A prerequisite to building or installing a distribution"""
+
+    def __init__(
+            self, name, requested_version, module, homepage='',
+            attribute=None, format=None):
+
+        if format is None and requested_version is not None:
+            format = StrictVersion
+
+        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 '%s-%s' % (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 version >= self.requested_version
+
+    def get_version(self, paths=None, default="unknown"):
+        """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)
+                if f:
+                    f.close()
+                return default
+            except ImportError:
+                return None
+
+        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(version)
+
+
+def maybe_close(f):
+    @contextlib.contextmanager
+    def empty():
+        yield
+        return
+    if not f:
+        return empty()
+
+    return contextlib.closing(f)
+
+
+def get_module_constant(module, symbol, default=-1, paths=None):
+    """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 = py27compat.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 = py27compat.get_module(module, paths, info)
+            return getattr(imported, symbol, None)
+
+    return extract_constant(code, symbol, default)
+
+
+def extract_constant(code, symbol, default=-1):
+    """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 = 90
+    STORE_GLOBAL = 97
+    LOAD_CONST = 100
+
+    const = default
+
+    for byte_code in Bytecode(code):
+        op = byte_code.opcode
+        arg = byte_code.arg
+
+        if op == LOAD_CONST:
+            const = code.co_consts[arg]
+        elif arg == name_idx and (op == STORE_NAME or op == STORE_GLOBAL):
+            return const
+        else:
+            const = default
+
+
+def _update_globals():
+    """
+    Patch the globals to remove the objects 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':
+        return
+    incompatible = 'extract_constant', 'get_module_constant'
+    for name in incompatible:
+        del globals()[name]
+        __all__.remove(name)
+
+
+_update_globals()