mercurial/utils/resourceutil.py

resourceutil: don't limit resources to the `mercurial` package

This should make things a little clearer, in that it now requires the full
package name to access a resource.  But the real motivation is that
`extensions._disabledpaths()` walks the `hgext` directory looking for bundled
extensions.  This in turn feeds, among other things:

    1) Listing disabled extensions in `hg help extensions`
    2) Indicating that an unknown command is in a non-enabled extension
    3) Displaying help for non-enabled extensions
    4) Generating documentation
    5) Announcing LFS is auto-enabled (or not) when cloning from an LFS source

The filesystem based ResourceReader will happily return *.py and *.pyc, but the
one supplied by PyOxidizer doesn't.  Presumably we can change that.  The only
other idea I had here is for setup.py to generate a text file containing the
list of extensions, but that doesn't seem great when running from source.

Differential Revision: https://phab.mercurial-scm.org/D7772

# resourceutil.py - utility for looking up resources
#
#  Copyright 2005 K. Thananchayan <[e-mail]>
#  Copyright 2005-2007 Matt Mackall <[e-mail]>
#  Copyright 2006 Vadim Gelfer <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import imp
import os
import sys

from .. import pycompat


def mainfrozen():
    """return True if we are a frozen executable.

    The code supports py2exe (most common, Windows only) and tools/freeze
    (portable, not much used).
    """
    return (
        pycompat.safehasattr(sys, "frozen")
        or pycompat.safehasattr(sys, "importers")  # new py2exe
        or imp.is_frozen("__main__")  # old py2exe
    )  # tools/freeze


# the location of data files matching the source code
if mainfrozen() and getattr(sys, 'frozen', None) != 'macosx_app':
    # executable version (py2exe) doesn't support __file__
    datapath = os.path.dirname(pycompat.sysexecutable)
else:
    datapath = os.path.dirname(os.path.dirname(pycompat.fsencode(__file__)))
    _rootpath = os.path.dirname(datapath)

try:
    from importlib import resources

    # Force loading of the resources module
    resources.open_binary  # pytype: disable=module-attr

    def open_resource(package, name):
        return resources.open_binary(  # pytype: disable=module-attr
            pycompat.sysstr(package), pycompat.sysstr(name)
        )


except (ImportError, AttributeError):

    def _package_path(package):
        return os.path.join(_rootpath, *package.split(b'.'))

    def open_resource(package, name):
        path = os.path.join(_package_path(package), name)
        return open(path, 'rb')