worker: avoid potential partial write of pickled data
Previously, the code wrote the pickled data using os.write(). However,
os.write() can write less bytes than passed to it. To trigger the problem, the
pickled data had to be larger than
2147479552 bytes on my system.
Instead, open a file object and pass it to pickle.dump(). This also has the
advantage that it doesn’t buffer the whole pickled data in memory.
Note that the opened file must be buffered because pickle doesn’t support
unbuffered streams because unbuffered streams’ write() method might write less
bytes than passed to it (like os.write()) but pickle.dump() relies on that all
bytes are written (see https://github.com/python/cpython/issues/93050).
The side effect of using a file object and a with statement is that wfd is
explicitly closed now while it seems like before it was implicitly closed by
process exit.
# config.py - configuration parsing for Mercurial
#
# Copyright 2009 Olivia Mackall <olivia@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import errno
import os
from .i18n import _
from .pycompat import getattr
from . import (
encoding,
error,
util,
)
class config:
def __init__(self, data=None):
self._current_source_level = 0
self._data = {}
self._unset = []
if data:
for k in data._data:
self._data[k] = data[k].copy()
self._current_source_level = data._current_source_level + 1
def new_source(self):
"""increment the source counter
This is used to define source priority when reading"""
self._current_source_level += 1
def copy(self):
return config(self)
def __contains__(self, section):
return section in self._data
def hasitem(self, section, item):
return item in self._data.get(section, {})
def __getitem__(self, section):
return self._data.get(section, {})
def __iter__(self):
for d in self.sections():
yield d
def update(self, src):
current_level = self._current_source_level
current_level += 1
max_level = self._current_source_level
for s, n in src._unset:
ds = self._data.get(s, None)
if ds is not None and n in ds:
self._data[s] = ds.preparewrite()
del self._data[s][n]
for s in src:
ds = self._data.get(s, None)
if ds:
self._data[s] = ds.preparewrite()
else:
self._data[s] = util.cowsortdict()
for k, v in src._data[s].items():
value, source, level = v
level += current_level
max_level = max(level, current_level)
self._data[s][k] = (value, source, level)
self._current_source_level = max_level
def _get(self, section, item):
return self._data.get(section, {}).get(item)
def get(self, section, item, default=None):
result = self._get(section, item)
if result is None:
return default
return result[0]
def backup(self, section, key):
"""return a tuple allowing restore to reinstall a previous value
The main reason we need it is because it handles the "no data" case.
"""
try:
item = self._data[section][key]
except KeyError:
return (section, key)
else:
return (section, key) + item
def source(self, section, item):
result = self._get(section, item)
if result is None:
return b""
return result[1]
def level(self, section, item):
result = self._get(section, item)
if result is None:
return None
return result[2]
def sections(self):
return sorted(self._data.keys())
def items(self, section):
items = self._data.get(section, {}).items()
return [(k, v[0]) for (k, v) in items]
def set(self, section, item, value, source=b""):
assert not isinstance(
section, str
), b'config section may not be unicode strings on Python 3'
assert not isinstance(
item, str
), b'config item may not be unicode strings on Python 3'
assert not isinstance(
value, str
), b'config values may not be unicode strings on Python 3'
if section not in self:
self._data[section] = util.cowsortdict()
else:
self._data[section] = self._data[section].preparewrite()
self._data[section][item] = (value, source, self._current_source_level)
def alter(self, section, key, new_value):
"""alter a value without altering its source or level
This method is meant to be used by `ui.fixconfig` only."""
item = self._data[section][key]
size = len(item)
new_item = (new_value,) + item[1:]
assert len(new_item) == size
self._data[section][key] = new_item
def restore(self, data):
"""restore data returned by self.backup"""
if len(data) != 2:
# restore old data
section, key = data[:2]
item = data[2:]
self._data[section] = self._data[section].preparewrite()
self._data[section][key] = item
else:
# no data before, remove everything
section, item = data
if section in self._data:
self._data[section].pop(item, None)
def parse(self, src, data, sections=None, remap=None, include=None):
sectionre = util.re.compile(br'\[([^\[]+)\]')
itemre = util.re.compile(br'([^=\s][^=]*?)\s*=\s*(.*\S|)')
contre = util.re.compile(br'\s+(\S|\S.*\S)\s*$')
emptyre = util.re.compile(br'(;|#|\s*$)')
commentre = util.re.compile(br'(;|#)')
unsetre = util.re.compile(br'%unset\s+(\S+)')
includere = util.re.compile(br'%include\s+(\S|\S.*\S)\s*$')
section = b""
item = None
line = 0
cont = False
if remap:
section = remap.get(section, section)
for l in data.splitlines(True):
line += 1
if line == 1 and l.startswith(b'\xef\xbb\xbf'):
# Someone set us up the BOM
l = l[3:]
if cont:
if commentre.match(l):
continue
m = contre.match(l)
if m:
if sections and section not in sections:
continue
v = self.get(section, item) + b"\n" + m.group(1)
self.set(section, item, v, b"%s:%d" % (src, line))
continue
item = None
cont = False
m = includere.match(l)
if m and include:
expanded = util.expandpath(m.group(1))
try:
include(expanded, remap=remap, sections=sections)
except IOError as inst:
if inst.errno != errno.ENOENT:
raise error.ConfigError(
_(b"cannot include %s (%s)")
% (expanded, encoding.strtolocal(inst.strerror)),
b"%s:%d" % (src, line),
)
continue
if emptyre.match(l):
continue
m = sectionre.match(l)
if m:
section = m.group(1)
if remap:
section = remap.get(section, section)
if section not in self:
self._data[section] = util.cowsortdict()
continue
m = itemre.match(l)
if m:
item = m.group(1)
cont = True
if sections and section not in sections:
continue
self.set(section, item, m.group(2), b"%s:%d" % (src, line))
continue
m = unsetre.match(l)
if m:
name = m.group(1)
if sections and section not in sections:
continue
if self.get(section, name) is not None:
self._data[section] = self._data[section].preparewrite()
del self._data[section][name]
self._unset.append((section, name))
continue
message = l.rstrip()
if l.startswith(b' '):
message = b"unexpected leading whitespace: %s" % message
raise error.ConfigError(message, (b"%s:%d" % (src, line)))
def read(self, path, fp=None, sections=None, remap=None):
self.new_source()
if not fp:
fp = util.posixfile(path, b'rb')
assert (
getattr(fp, 'mode', 'rb') == 'rb'
), b'config files must be opened in binary mode, got fp=%r mode=%r' % (
fp,
fp.mode,
)
dir = os.path.dirname(path)
def include(rel, remap, sections):
abs = os.path.normpath(os.path.join(dir, rel))
self.read(abs, remap=remap, sections=sections)
# anything after the include has a higher level
self.new_source()
self.parse(
path, fp.read(), sections=sections, remap=remap, include=include
)