view mercurial/utils/resourceutil.py @ 47338:f27f2afb15da

dirstate-tree: Skip readdir() in `hg status -mard`

When running the status algorithm in a mode where we don’t list unknown
or ignored files, all we care about are files that are listed in the dirstate.
We can there for skip making expensive calls to readdir() to list the contents
of filesystem directories, and instead only run stat() to get the filesystem
state of files listed in the dirstate. (This state may be an error for files
that don’t exist anymore on the filesystem.)

On 16 CPU threads, this reduces the time spent in the `status()` function for
`hg status -mard` on an old snapshot of mozilla-central from ~70ms to ~50ms.

Differential Revision: https://phab.mercurial-scm.org/D10752

# resourceutil.py - utility for looking up resources
#
#  Copyright 2005 K. Thananchayan <[e-mail]>
#  Copyright 2005-2007 Olivia 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")  # new py2exe
        or pycompat.safehasattr(sys, "importers")  # old py2exe
        or imp.is_frozen("__main__")  # 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)
    _rootpath = datapath

    # The installers store the files outside of library.zip, like
    # C:\Program Files\Mercurial\defaultrc\*.rc.  This strips the
    # leading "mercurial." off of the package name, so that these
    # pseudo resources are found in their directory next to the
    # executable.
    def _package_path(package):
        dirs = package.split(b".")
        assert dirs[0] == b"mercurial"
        return os.path.join(_rootpath, *dirs[1:])


else:
    datapath = os.path.dirname(os.path.dirname(pycompat.fsencode(__file__)))
    _rootpath = os.path.dirname(datapath)

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


try:
    # importlib.resources exists from Python 3.7; see fallback in except clause
    # further down
    from importlib import resources

    from .. import encoding

    # 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)
        )

    def is_resource(package, name):
        return resources.is_resource(  # pytype: disable=module-attr
            pycompat.sysstr(package), encoding.strfromlocal(name)
        )

    def contents(package):
        # pytype: disable=module-attr
        for r in resources.contents(pycompat.sysstr(package)):
            # pytype: enable=module-attr
            yield encoding.strtolocal(r)


except (ImportError, AttributeError):
    # importlib.resources was not found (almost definitely because we're on a
    # Python version before 3.7)

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

    def is_resource(package, name):
        path = os.path.join(_package_path(package), name)

        try:
            return os.path.isfile(pycompat.fsdecode(path))
        except (IOError, OSError):
            return False

    def contents(package):
        path = pycompat.fsdecode(_package_path(package))

        for p in os.listdir(path):
            yield pycompat.fsencode(p)