mercurial/thirdparty/attr/_compat.py

completion: install completers to conventional locations

Installs the bash and zsh completers to the convential locations so they will
automatically be picked up without user intervention.  The zsh completer
on Debian is still installed to vendor-completions to match their policy.

bash: https://github.com/scop/bash-completion#faq
zsh: https://github.com/zsh-users/zsh/blob/57305cf245853b8b30895b41a90142dffab97e38/INSTALL#L254
Debian zsh: https://salsa.debian.org/debian/zsh/-/blob/5086b5356abcef8849dc8a09902b7c55f01db3c0/debian/README.Debian#L73

from __future__ import absolute_import, division, print_function

import sys
import types


PY2 = sys.version_info[0] == 2


if PY2:
    from UserDict import IterableUserDict

    # We 'bundle' isclass instead of using inspect as importing inspect is
    # fairly expensive (order of 10-15 ms for a modern machine in 2016)
    def isclass(klass):
        return isinstance(klass, (type, types.ClassType))

    # TYPE is used in exceptions, repr(int) is different on Python 2 and 3.
    TYPE = "type"

    def iteritems(d):
        return d.iteritems()

    def iterkeys(d):
        return d.iterkeys()

    # Python 2 is bereft of a read-only dict proxy, so we make one!
    class ReadOnlyDict(IterableUserDict):
        """
        Best-effort read-only dict wrapper.
        """

        def __setitem__(self, key, val):
            # We gently pretend we're a Python 3 mappingproxy.
            raise TypeError("'mappingproxy' object does not support item "
                            "assignment")

        def update(self, _):
            # We gently pretend we're a Python 3 mappingproxy.
            raise AttributeError("'mappingproxy' object has no attribute "
                                 "'update'")

        def __delitem__(self, _):
            # We gently pretend we're a Python 3 mappingproxy.
            raise TypeError("'mappingproxy' object does not support item "
                            "deletion")

        def clear(self):
            # We gently pretend we're a Python 3 mappingproxy.
            raise AttributeError("'mappingproxy' object has no attribute "
                                 "'clear'")

        def pop(self, key, default=None):
            # We gently pretend we're a Python 3 mappingproxy.
            raise AttributeError("'mappingproxy' object has no attribute "
                                 "'pop'")

        def popitem(self):
            # We gently pretend we're a Python 3 mappingproxy.
            raise AttributeError("'mappingproxy' object has no attribute "
                                 "'popitem'")

        def setdefault(self, key, default=None):
            # We gently pretend we're a Python 3 mappingproxy.
            raise AttributeError("'mappingproxy' object has no attribute "
                                 "'setdefault'")

        def __repr__(self):
            # Override to be identical to the Python 3 version.
            return "mappingproxy(" + repr(self.data) + ")"

    def metadata_proxy(d):
        res = ReadOnlyDict()
        res.data.update(d)  # We blocked update, so we have to do it like this.
        return res

else:
    def isclass(klass):
        return isinstance(klass, type)

    TYPE = "class"

    def iteritems(d):
        return d.items()

    def iterkeys(d):
        return d.keys()

    def metadata_proxy(d):
        return types.MappingProxyType(dict(d))