perf: introduce safeattrsetter to replace direct attribute assignment
Referring not-existing attribute immediately causes failure, but
assigning a value to such attribute doesn't.
For example, perf.py has code paths below, which assign a value to
not-existing attribute. This causes incorrect performance measurement,
but these code paths are executed successfully.
- "repo._tags = None" in perftags()
recent Mercurial has tags cache information in repo._tagscache
- "branchmap.write = lambda repo: None" in perfbranchmap()
branchmap cache is written out by branchcache.write() in branchmap.py
"util.safehasattr() before assignment" can avoid this issue, but might
increase mistake at "copy & paste" attribute name or so.
To centralize (1) examining existence of, (2) assigning a value to,
and (3) restoring an old value to the attribute, this patch introduces
safeattrsetter(). This is used to replace direct attribute assignment
in subsequent patches.
Encapsulation of restoring is needed to completely remove direct
attribute assignment from perf.py, even though restoring isn't needed
so often.
#!/usr/bin/env python
"""
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
"""
from __future__ import absolute_import
import glob
import hashlib
import optparse
import os
import re
import sys
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('%s: file not found\n' % f)
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('file')
if opts.hexdump or opts.dump or opts.md5:
content = file(f, 'rb').read()
elif islink:
if opts.type:
facts.append('link')
content = os.readlink(f)
elif isstdin:
content = sys.stdin.read()
if opts.size:
facts.append('size=%s' % len(content))
elif isdir:
if opts.recurse or opts.type:
dirfiles = glob.glob(f + '/*')
facts.append('directory with %s files' % len(dirfiles))
elif opts.type:
facts.append('type unknown')
if not isstdin:
stat = os.lstat(f)
if opts.size and not isdir:
facts.append('size=%s' % stat.st_size)
if opts.mode and not islink:
facts.append('mode=%o' % (stat.st_mode & 0o777))
if opts.links:
facts.append('links=%s' % 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('newer than %s' % opts.newer)
else:
facts.append('older than %s' % opts.newer)
if opts.md5 and content is not None:
h = hashlib.md5(content)
facts.append('md5=%s' % h.hexdigest()[:opts.bytes])
if opts.sha1 and content is not None:
h = hashlib.sha1(content)
facts.append('sha1=%s' % h.hexdigest()[:opts.bytes])
if isstdin:
outfile.write(', '.join(facts) + '\n')
elif facts:
outfile.write('%s: %s\n' % (f, ', '.join(facts)))
elif not quiet:
outfile.write('%s:\n' % f)
if content is not None:
chunk = content
if not islink:
if opts.lines:
if opts.lines >= 0:
chunk = ''.join(chunk.splitlines(True)[:opts.lines])
else:
chunk = ''.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('%04x: %-47s |%s|\n' %
(i, ' '.join('%02x' % ord(c) for c in s),
re.sub('[^ -~]', '.', s)))
if opts.dump:
if not quiet:
outfile.write('>>>\n')
outfile.write(chunk)
if not quiet:
if chunk.endswith('\n'):
outfile.write('<<<\n')
else:
outfile.write('\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("-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, sys.stdout)