view contrib/python-zstandard/setup.py @ 32151:4d504e541d3d

rebase: use matcher to optimize manifestmerge

The old merge code would call manifestmerge and calculate the complete diff
between the source to the destination. In many cases, like rebase, the vast
majority of differences between the source and destination are irrelevant
because they are differences between the destination and the common ancestor
only, and therefore don't affect the merge. Since most actions are 'keep', all
the effort to compute them is wasted.

Instead, let's compute the difference between the source and the common ancestor
and only perform the diff of those files against the merge destination. When
using treemanifest, this lets us avoid loading almost the entire tree when
rebasing from a very old ancestor. This speeds up rebase of an old stack of 27
commits by 20x.

In mozilla-central, without treemanifest, when rebasing a commit from
default~100000 to default, this speeds up the manifestmerge step from 2.6s to
1.2s.  However, the additional diff adds an overhead to all manifestmerge calls,
especially for flat manifests. When rebasing a commit from default~1 to default
it appears to add 100ms in mozilla-central. While we could put this optimization
behind a flag, I think the fact that it makes merge O(number of changes being
applied) instead of O(number of changes between X and Y) justifies it.

#!/usr/bin/env python
# Copyright (c) 2016-present, Gregory Szorc
# All rights reserved.
#
# This software may be modified and distributed under the terms
# of the BSD license. See the LICENSE file for details.

import sys
from setuptools import setup

try:
    import cffi
except ImportError:
    cffi = None

import setup_zstd

SUPPORT_LEGACY = False

if "--legacy" in sys.argv:
    SUPPORT_LEGACY = True
    sys.argv.remove("--legacy")

# Code for obtaining the Extension instance is in its own module to
# facilitate reuse in other projects.
extensions = [setup_zstd.get_c_extension(SUPPORT_LEGACY, 'zstd')]

install_requires = []

if cffi:
    import make_cffi
    extensions.append(make_cffi.ffi.distutils_extension())

    # Need change in 1.8 for ffi.from_buffer() behavior.
    install_requires.append('cffi>=1.8')

version = None

with open('c-ext/python-zstandard.h', 'r') as fh:
    for line in fh:
        if not line.startswith('#define PYTHON_ZSTANDARD_VERSION'):
            continue

        version = line.split()[2][1:-1]
        break

if not version:
    raise Exception('could not resolve package version; '
                    'this should never happen')

setup(
    name='zstandard',
    version=version,
    description='Zstandard bindings for Python',
    long_description=open('README.rst', 'r').read(),
    url='https://github.com/indygreg/python-zstandard',
    author='Gregory Szorc',
    author_email='[e-mail]',
    license='BSD',
    classifiers=[
        'Development Status :: 4 - Beta',
        'Intended Audience :: Developers',
        'License :: OSI Approved :: BSD License',
        'Programming Language :: C',
        'Programming Language :: Python :: 2.6',
        'Programming Language :: Python :: 2.7',
        'Programming Language :: Python :: 3.3',
        'Programming Language :: Python :: 3.4',
        'Programming Language :: Python :: 3.5',
        'Programming Language :: Python :: 3.6',
    ],
    keywords='zstandard zstd compression',
    ext_modules=extensions,
    test_suite='tests',
    install_requires=install_requires,
)