procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/usr/bin/env python3
"""
Utility for inspecting files in various ways.
This tool is like the collection of tools found in a unix environment but are
cross platform and stable and suitable for our needs in the test suite.
This can be used instead of tools like:
[
dd
find
head
hexdump
ls
md5sum
readlink
sha1sum
stat
tail
test
readlink.py
md5sum.py
"""
import binascii
import glob
import hashlib
import optparse
import os
import re
import sys
# Python 3 adapters
ispy3 = sys.version_info[0] >= 3
if ispy3:
def iterbytes(s):
for i in range(len(s)):
yield s[i : i + 1]
else:
iterbytes = iter
def visit(opts, filenames, outfile):
"""Process filenames in the way specified in opts, writing output to
outfile."""
for f in sorted(filenames):
isstdin = f == '-'
if not isstdin and not os.path.lexists(f):
outfile.write(b'%s: file not found\n' % f.encode('utf-8'))
continue
quiet = opts.quiet and not opts.recurse or isstdin
isdir = os.path.isdir(f)
islink = os.path.islink(f)
isfile = os.path.isfile(f) and not islink
dirfiles = None
content = None
facts = []
if isfile:
if opts.type:
facts.append(b'file')
if any((opts.hexdump, opts.dump, opts.md5, opts.sha1, opts.sha256)):
with open(f, 'rb') as fobj:
content = fobj.read()
elif islink:
if opts.type:
facts.append(b'link')
content = os.readlink(f).encode('utf8')
elif isstdin:
content = getattr(sys.stdin, 'buffer', sys.stdin).read()
if opts.size:
facts.append(b'size=%d' % len(content))
elif isdir:
if opts.recurse or opts.type:
dirfiles = glob.glob(f + '/*')
facts.append(b'directory with %d files' % len(dirfiles))
elif opts.type:
facts.append(b'type unknown')
if not isstdin:
stat = os.lstat(f)
if opts.size and not isdir:
facts.append(b'size=%d' % stat.st_size)
if opts.mode and not islink:
facts.append(b'mode=%o' % (stat.st_mode & 0o777))
if opts.links:
facts.append(b'links=%d' % stat.st_nlink)
if opts.newer:
# mtime might be in whole seconds so newer file might be same
if stat.st_mtime >= os.stat(opts.newer).st_mtime:
facts.append(
b'newer than %s' % opts.newer.encode('utf8', 'replace')
)
else:
facts.append(
b'older than %s' % opts.newer.encode('utf8', 'replace')
)
if opts.md5 and content is not None:
h = hashlib.md5(content)
facts.append(b'md5=%s' % binascii.hexlify(h.digest())[: opts.bytes])
if opts.sha1 and content is not None:
h = hashlib.sha1(content)
facts.append(
b'sha1=%s' % binascii.hexlify(h.digest())[: opts.bytes]
)
if opts.sha256 and content is not None:
h = hashlib.sha256(content)
facts.append(
b'sha256=%s' % binascii.hexlify(h.digest())[: opts.bytes]
)
if isstdin:
outfile.write(b', '.join(facts) + b'\n')
elif facts:
outfile.write(b'%s: %s\n' % (f.encode('utf-8'), b', '.join(facts)))
elif not quiet:
outfile.write(b'%s:\n' % f.encode('utf-8'))
if content is not None:
chunk = content
if not islink:
if opts.lines:
if opts.lines >= 0:
chunk = b''.join(chunk.splitlines(True)[: opts.lines])
else:
chunk = b''.join(chunk.splitlines(True)[opts.lines :])
if opts.bytes:
if opts.bytes >= 0:
chunk = chunk[: opts.bytes]
else:
chunk = chunk[opts.bytes :]
if opts.hexdump:
for i in range(0, len(chunk), 16):
s = chunk[i : i + 16]
outfile.write(
b'%04x: %-47s |%s|\n'
% (
i,
b' '.join(b'%02x' % ord(c) for c in iterbytes(s)),
re.sub(b'[^ -~]', b'.', s),
)
)
if opts.dump:
if not quiet:
outfile.write(b'>>>\n')
outfile.write(chunk)
if not quiet:
if chunk.endswith(b'\n'):
outfile.write(b'<<<\n')
else:
outfile.write(b'\n<<< no trailing newline\n')
if opts.recurse and dirfiles:
assert not isstdin
visit(opts, dirfiles, outfile)
if __name__ == "__main__":
parser = optparse.OptionParser("%prog [options] [filenames]")
parser.add_option(
"-t",
"--type",
action="store_true",
help="show file type (file or directory)",
)
parser.add_option(
"-m", "--mode", action="store_true", help="show file mode"
)
parser.add_option(
"-l", "--links", action="store_true", help="show number of links"
)
parser.add_option(
"-s", "--size", action="store_true", help="show size of file"
)
parser.add_option(
"-n", "--newer", action="store", help="check if file is newer (or same)"
)
parser.add_option(
"-r", "--recurse", action="store_true", help="recurse into directories"
)
parser.add_option(
"-S",
"--sha1",
action="store_true",
help="show sha1 hash of the content",
)
parser.add_option(
"",
"--sha256",
action="store_true",
help="show sha256 hash of the content",
)
parser.add_option(
"-M", "--md5", action="store_true", help="show md5 hash of the content"
)
parser.add_option(
"-D", "--dump", action="store_true", help="dump file content"
)
parser.add_option(
"-H", "--hexdump", action="store_true", help="hexdump file content"
)
parser.add_option(
"-B", "--bytes", type="int", help="number of characters to dump"
)
parser.add_option(
"-L", "--lines", type="int", help="number of lines to dump"
)
parser.add_option(
"-q", "--quiet", action="store_true", help="no default output"
)
(opts, filenames) = parser.parse_args(sys.argv[1:])
if not filenames:
filenames = ['-']
visit(opts, filenames, getattr(sys.stdout, 'buffer', sys.stdout))