Mercurial > hg
view mercurial/pathutil.py @ 29861:2f6d5c60f6fc stable
annotate: pre-calculate the "needed" dictionary (issue5360)
The "needed" dict is used as a reference counter to free items in the giant
"hist" dict. However, currently it is not very accurate and can lead to
dropping "hist" items unnecessarily, for example, with the following DAG,
-3-
/ \
0--1--2--4--
The current algorithm will visit and calculate rev 1 twice, undesired. And
it tries to be smart by clearing rev 1's parents: "pcache[1] = []" at the
time hist[1] being accessed (note: hist[1] needs to be used twice, by rev 2
and rev 3). It can result in incorrect results if p1 of rev 4 deletes chunks
belonging to rev 0.
However, simply removing "needed" is not okay, because it will consume 10x
memory:
# without any change
% HGRCPATH= lrun ./hg annotate mercurial/commands.py -r d130a38 3>&2 [1]
MEMORY 49074176
CPUTIME 9.213
REALTIME 9.270
# with "needed" removed
MEMORY 637673472
CPUTIME 8.164
REALTIME 8.249
This patch moves "needed" (and "pcache") calculation to a separate DFS to
address the issue. It improves perf and fixes issue5360 by correctly reusing
hist, while maintaining low memory usage. Some additional attempt has been
made to further reduce memory usage, like changing "pcache[f] = []" to "del
pcache[f]". Therefore the result can be both faster and lower memory usage:
# with this patch applied
MEMORY 47575040
CPUTIME 7.870
REALTIME 7.926
[1]: lrun is a lightweight sandbox built on Linux cgroup and namespace. It's
used to measure CPU and memory usage here. Source code is available at
github.com/quark-zju/lrun.
author | Jun Wu <quark@fb.com> |
---|---|
date | Fri, 02 Sep 2016 15:20:59 +0100 |
parents | 0b7ce0b16d8a |
children | 6f447b9ec263 |
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from __future__ import absolute_import import errno import os import posixpath import stat from .i18n import _ from . import ( encoding, error, util, ) 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 ".." More check are also done about the file system states: - 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) The file system checks are only done when 'realfs' is set to True (the default). They should be disable then we are auditing path for operation on stored history. ''' def __init__(self, root, callback=None, realfs=True): self.audited = set() self.auditeddir = set() self.root = root self._realfs = realfs 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 error.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 error.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 error.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 error.Abort(_("path '%s' is inside nested repo %r") % (path, base)) normparts = util.splitpath(normpath) assert len(parts) == len(normparts) parts.pop() normparts.pop() prefixes = [] # It's important that we check the path parts starting from the root. # This means we won't accidentaly traverse a symlink into some other # filesystem (which is potentially expensive to access). for i in range(len(parts)): prefix = os.sep.join(parts[:i + 1]) normprefix = os.sep.join(normparts[:i + 1]) if normprefix in self.auditeddir: continue if self._realfs: self._checkfs(prefix, path) prefixes.append(normprefix) 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 _checkfs(self, prefix, path): """raise exception if a file system backed check fails""" curpath = os.path.join(self.root, prefix) try: st = os.lstat(curpath) except OSError as 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): msg = _('path %r traverses symbolic link %r') % (path, prefix) raise error.Abort(msg) 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): msg = _("path '%s' is inside nested repo %r") raise error.Abort(msg % (path, prefix)) def check(self, path): try: self(path) return True except (OSError, error.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 # A common mistake is to use -R, but specify a file relative to the repo # instead of cwd. Detect that case, and provide a hint to the user. hint = None try: if cwd != root: canonpath(root, root, myname, auditor) hint = (_("consider using '--cwd %s'") % os.path.relpath(root, cwd)) except error.Abort: pass raise error.Abort(_("%s not under root '%s'") % (myname, root), hint=hint) 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 # forward two methods from posixpath that do what we need, but we'd # rather not let our internals know that we're thinking in posix terms # - instead we'll let them be oblivious. join = posixpath.join dirname = posixpath.dirname