Small Python modernization of Brotli code.

PiperOrigin-RevId: 549289787
This commit is contained in:
Thomas Fischbacher 2023-07-19 05:43:51 -07:00 committed by Copybara-Service
parent 4b827e4ce4
commit acc265655d

View File

@ -1,7 +1,11 @@
#! /usr/bin/env python
"""Compression/decompression utility using the Brotli algorithm."""
# Note: Python2 has been deprecated long ago, but some projects out in
# the wide world may still use it nevertheless. This should not
# deprive them from being able to run Brotli.
from __future__ import print_function
import argparse
import os
import platform
@ -9,8 +13,9 @@ import sys
import brotli
# default values of encoder parameters
DEFAULT_PARAMS = {
_DEFAULT_PARAMS = {
'mode': brotli.MODE_GENERIC,
'quality': 11,
'lgwin': 22,
@ -19,17 +24,32 @@ DEFAULT_PARAMS = {
def get_binary_stdio(stream):
""" Return the specified standard input, output or errors stream as a
'raw' buffer object suitable for reading/writing binary data from/to it.
"""Return the specified stdin/stdout/stderr stream.
If the stdio stream requested (i.e. sys.(stdin|stdout|stderr))
has been replaced with a stream object that does not have a `.buffer`
attribute, this will return the original stdio stream's buffer, i.e.
`sys.__(stdin|stdout|stderr)__.buffer`.
Args:
stream: One of 'stdin', 'stdout', 'stderr'.
Returns:
The stream, as a 'raw' buffer object (i.e. io.BufferedIOBase subclass
instance such as io.Bufferedreader/io.BufferedWriter), suitable for
reading/writing binary data from/to it.
"""
assert stream in ['stdin', 'stdout', 'stderr'], 'invalid stream name'
stdio = getattr(sys, stream)
if stream == 'stdin': stdio = sys.stdin
elif stream == 'stdout': stdio = sys.stdout
elif stream == 'stderr': stdio = sys.stderr
else:
raise ValueError('invalid stream name: %s' % (stream,))
if sys.version_info[0] < 3:
if sys.platform == 'win32':
# set I/O stream binary flag on python2.x (Windows)
runtime = platform.python_implementation()
if runtime == 'PyPy':
# the msvcrt trick doesn't work in pypy, so I use fdopen
# the msvcrt trick doesn't work in pypy, so use fdopen().
mode = 'rb' if stream == 'stdin' else 'wb'
stdio = os.fdopen(stdio.fileno(), mode, 0)
else:
@ -38,12 +58,20 @@ def get_binary_stdio(stream):
msvcrt.setmode(stdio.fileno(), os.O_BINARY)
return stdio
else:
# get 'buffer' attribute to read/write binary data on python3.x
if hasattr(stdio, 'buffer'):
try:
return stdio.buffer
else:
orig_stdio = getattr(sys, '__%s__' % stream)
return orig_stdio.buffer
except AttributeError:
# The Python reference explains
# (-> https://docs.python.org/3/library/sys.html#sys.stdin)
# that the `.buffer` attribute might not exist, since
# the standard streams might have been replaced by something else
# (such as an `io.StringIO()` - perhaps via
# `contextlib.redirect_stdout()`).
# We fall back to the original stdio in these cases.
if stream == 'stdin': return sys.__stdin__.buffer
if stream == 'stdout': return sys.__stdout__.buffer
if stream == 'stderr': return sys.__stderr__.buffer
assert False, 'Impossible Situation.'
def main(args=None):
@ -114,30 +142,36 @@ def main(args=None):
help='Base 2 logarithm of the maximum input block size. '
'Range is 16 to 24. If set to 0, the value will be set based '
'on the quality. Defaults to 0.')
# set default values using global DEFAULT_PARAMS dictionary
parser.set_defaults(**DEFAULT_PARAMS)
# set default values using global _DEFAULT_PARAMS dictionary
parser.set_defaults(**_DEFAULT_PARAMS)
options = parser.parse_args(args=args)
if options.infile:
if not os.path.isfile(options.infile):
parser.error('file "%s" not found' % options.infile)
try:
with open(options.infile, 'rb') as infile:
data = infile.read()
except OSError:
parser.error('Could not read --infile: %s' % (infile,))
else:
if sys.stdin.isatty():
# interactive console, just quit
parser.error('no input')
parser.error('No input (called from interactive terminal).')
infile = get_binary_stdio('stdin')
data = infile.read()
if options.outfile:
if os.path.isfile(options.outfile) and not options.force:
parser.error('output file exists')
# Caution! If `options.outfile` is a broken symlink, will try to
# redirect the write according to symlink.
if os.path.exists(options.outfile) and not options.force:
parser.error(('Target --outfile=%s already exists, '
'but --force was not requested.') % (outfile,))
outfile = open(options.outfile, 'wb')
did_open_outfile = True
else:
outfile = get_binary_stdio('stdout')
did_open_outfile = False
try:
try:
if options.decompress:
data = brotli.decompress(data)
@ -148,12 +182,12 @@ def main(args=None):
quality=options.quality,
lgwin=options.lgwin,
lgblock=options.lgblock)
outfile.write(data)
finally:
if did_open_outfile: outfile.close()
except brotli.error as e:
parser.exit(1,
'bro: error: %s: %s' % (e, options.infile or 'sys.stdin'))
outfile.write(data)
outfile.close()
'bro: error: %s: %s' % (e, options.infile or '{stdin}'))
if __name__ == '__main__':