tags: extract .hgtags filenodes cache to a standalone file
Resolution of .hgtags filenodes values has historically been a
performance pain point for large repositories, where reading individual
manifests can take over 100ms. Multiplied by hundreds or even thousands
of heads and resolving .hgtags filenodes becomes a performance issue.
This patch establishes a standalone cache file holding the .hgtags
filenodes for each changeset. After this patch, the .hgtags filenode
for any particular changeset should only have to be computed once
during the lifetime of the repository.
The introduced hgtagsfnodes1 cache file is modeled after the rev branch
cache: the cache is effectively an array of entries consisting of a
changeset fragment and the filenode for a revision. The file grows in
proportion to the length of the repository (24 bytes per changeset) and
is truncated when the repository is stripped. The file is not written
unless tag info is requested and tags have changed since last time.
This patch partially addresses issue4550. Future patches will split the
"tags" cache file into per-filter files and will refactor the cache
format to not capture the .hgtags fnodes, as these are now stored in
the hgtagsfnodes1 cache. This patch is capable of standing alone. We
should not have to wait on the tags cache filter split and format
refactor for this patch to land.
import os, errno, stat
import encoding
import util
from i18n import _
def _lowerclean(s):
return encoding.hfsignoreclean(s.lower())
class pathauditor(object):
'''ensure that a filesystem path contains no banned components.
the following properties of a path are checked:
- ends with a directory separator
- under top-level .hg
- starts at the root of a windows drive
- contains ".."
- traverses a symlink (e.g. a/symlink_here/b)
- inside a nested repository (a callback can be used to approve
some nested repositories, e.g., subrepositories)
'''
def __init__(self, root, callback=None):
self.audited = set()
self.auditeddir = set()
self.root = root
self.callback = callback
if os.path.lexists(root) and not util.checkcase(root):
self.normcase = util.normcase
else:
self.normcase = lambda x: x
def __call__(self, path):
'''Check the relative path.
path may contain a pattern (e.g. foodir/**.txt)'''
path = util.localpath(path)
normpath = self.normcase(path)
if normpath in self.audited:
return
# AIX ignores "/" at end of path, others raise EISDIR.
if util.endswithsep(path):
raise util.Abort(_("path ends in directory separator: %s") % path)
parts = util.splitpath(path)
if (os.path.splitdrive(path)[0]
or _lowerclean(parts[0]) in ('.hg', '.hg.', '')
or os.pardir in parts):
raise util.Abort(_("path contains illegal component: %s") % path)
# Windows shortname aliases
for p in parts:
if "~" in p:
first, last = p.split("~", 1)
if last.isdigit() and first.upper() in ["HG", "HG8B6C"]:
raise util.Abort(_("path contains illegal component: %s")
% path)
if '.hg' in _lowerclean(path):
lparts = [_lowerclean(p.lower()) for p in parts]
for p in '.hg', '.hg.':
if p in lparts[1:]:
pos = lparts.index(p)
base = os.path.join(*parts[:pos])
raise util.Abort(_("path '%s' is inside nested repo %r")
% (path, base))
normparts = util.splitpath(normpath)
assert len(parts) == len(normparts)
parts.pop()
normparts.pop()
prefixes = []
while parts:
prefix = os.sep.join(parts)
normprefix = os.sep.join(normparts)
if normprefix in self.auditeddir:
break
curpath = os.path.join(self.root, prefix)
try:
st = os.lstat(curpath)
except OSError, err:
# EINVAL can be raised as invalid path syntax under win32.
# They must be ignored for patterns can be checked too.
if err.errno not in (errno.ENOENT, errno.ENOTDIR, errno.EINVAL):
raise
else:
if stat.S_ISLNK(st.st_mode):
raise util.Abort(
_('path %r traverses symbolic link %r')
% (path, prefix))
elif (stat.S_ISDIR(st.st_mode) and
os.path.isdir(os.path.join(curpath, '.hg'))):
if not self.callback or not self.callback(curpath):
raise util.Abort(_("path '%s' is inside nested "
"repo %r")
% (path, prefix))
prefixes.append(normprefix)
parts.pop()
normparts.pop()
self.audited.add(normpath)
# only add prefixes to the cache after checking everything: we don't
# want to add "foo/bar/baz" before checking if there's a "foo/.hg"
self.auditeddir.update(prefixes)
def check(self, path):
try:
self(path)
return True
except (OSError, util.Abort):
return False
def canonpath(root, cwd, myname, auditor=None):
'''return the canonical path of myname, given cwd and root'''
if util.endswithsep(root):
rootsep = root
else:
rootsep = root + os.sep
name = myname
if not os.path.isabs(name):
name = os.path.join(root, cwd, name)
name = os.path.normpath(name)
if auditor is None:
auditor = pathauditor(root)
if name != rootsep and name.startswith(rootsep):
name = name[len(rootsep):]
auditor(name)
return util.pconvert(name)
elif name == root:
return ''
else:
# Determine whether `name' is in the hierarchy at or beneath `root',
# by iterating name=dirname(name) until that causes no change (can't
# check name == '/', because that doesn't work on windows). The list
# `rel' holds the reversed list of components making up the relative
# file name we want.
rel = []
while True:
try:
s = util.samefile(name, root)
except OSError:
s = False
if s:
if not rel:
# name was actually the same as root (maybe a symlink)
return ''
rel.reverse()
name = os.path.join(*rel)
auditor(name)
return util.pconvert(name)
dirname, basename = util.split(name)
rel.append(basename)
if dirname == name:
break
name = dirname
raise util.Abort(_("%s not under root '%s'") % (myname, root))
def normasprefix(path):
'''normalize the specified path as path prefix
Returned value can be used safely for "p.startswith(prefix)",
"p[len(prefix):]", and so on.
For efficiency, this expects "path" argument to be already
normalized by "os.path.normpath", "os.path.realpath", and so on.
See also issue3033 for detail about need of this function.
>>> normasprefix('/foo/bar').replace(os.sep, '/')
'/foo/bar/'
>>> normasprefix('/').replace(os.sep, '/')
'/'
'''
d, p = os.path.splitdrive(path)
if len(p) != len(os.sep):
return path + os.sep
else:
return path