blob: 8bc65e6f39558c9d8b178b2c5265d4fe65a23227 [file] [log] [blame]
# -*- coding: utf-8 -*-
# Copyright 2020 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Run xz from PATH with a thread for each core in the system."""
from __future__ import division
from __future__ import print_function
import multiprocessing
import os
import sys
from chromite.lib import commandline
from chromite.lib import osutils
from chromite.utils import memoize
assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'
def HasPixz():
"""Returns path to pixz if it's on PATH or None otherwise."""
return osutils.Which('pixz')
def GetJobCount():
"""Returns half of the total number of the machine's CPUs as a string.
Returns half rather than all of them to avoid starving out other parallel
processes on the same machine.
return str(int(max(1, multiprocessing.cpu_count() / 2)))
def GetDecompressCommand(stdout):
"""Returns decompression command."""
if HasPixz():
cmd = ['pixz', '-d', '-p', GetJobCount()]
if stdout:
# Explicitly tell pixz the file is the input, so it will dump the output
# to stdout, instead of automatically choosing an output name.
return cmd
if stdout:
return ['xz', '-dc']
return ['xz', '-d']
def GetParser():
"""Return a command line parser."""
parser = commandline.ArgumentParser(description=__doc__)
help='Decompress rather than compress.',
help="Write to standard output and don't delete input files.")
return parser
def main(argv):
parser = GetParser()
known_args, argv = parser.parse_known_args()
if '-i' in argv or '-o' in argv:
parser.error('It is invalid to use -i or -o with xz_auto')
# xz doesn't support multi-threaded decompression, so try using pixz for that.
if known_args.decompress:
args = GetDecompressCommand(known_args.stdout)
os.execvp(args[0], args + argv)
cmd = ['xz', '-T0']
if known_args.stdout:
os.execvp(cmd[0], cmd + argv)