Mercurial > hg
view mercurial/scmutil.py @ 17952:54cedee86e51 stable
commit: increase perf by avoiding checks against entire repo subsets
When commiting to a repo with lots of history (>400000 changesets)
checking the results of revset.py:descendants against the subset takes
some time. Since the subset equals the entire changelog, the check
isn't necessary. Avoiding it in that case saves 0.1 seconds off of
a 1.78 second commit. A 6% gain.
We use the length of the subset to determine if it is the entire repo.
There is precedence for this in revset.py:stringset.
author | Durham Goode <durham@fb.com> |
---|---|
date | Fri, 16 Nov 2012 15:39:12 -0800 |
parents | 71c1513fd560 |
children | 3cb032d50447 f9a89bdd64a6 |
line wrap: on
line source
# scmutil.py - Mercurial core utility functions # # Copyright Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from i18n import _ import util, error, osutil, revset, similar, encoding, phases import match as matchmod import os, errno, re, stat, sys, glob def nochangesfound(ui, repo, excluded=None): '''Report no changes for push/pull, excluded is None or a list of nodes excluded from the push/pull. ''' secretlist = [] if excluded: for n in excluded: ctx = repo[n] if ctx.phase() >= phases.secret and not ctx.extinct(): secretlist.append(n) if secretlist: ui.status(_("no changes found (ignored %d secret changesets)\n") % len(secretlist)) else: ui.status(_("no changes found\n")) def checknewlabel(repo, lbl, kind): if lbl in ['tip', '.', 'null']: raise util.Abort(_("the name '%s' is reserved") % lbl) for c in (':', '\0', '\n', '\r'): if c in lbl: raise util.Abort(_("%r cannot be used in a name") % c) def checkfilename(f): '''Check that the filename f is an acceptable filename for a tracked file''' if '\r' in f or '\n' in f: raise util.Abort(_("'\\n' and '\\r' disallowed in filenames: %r") % f) def checkportable(ui, f): '''Check if filename f is portable and warn or abort depending on config''' checkfilename(f) abort, warn = checkportabilityalert(ui) if abort or warn: msg = util.checkwinfilename(f) if msg: msg = "%s: %r" % (msg, f) if abort: raise util.Abort(msg) ui.warn(_("warning: %s\n") % msg) def checkportabilityalert(ui): '''check if the user's config requests nothing, a warning, or abort for non-portable filenames''' val = ui.config('ui', 'portablefilenames', 'warn') lval = val.lower() bval = util.parsebool(val) abort = os.name == 'nt' or lval == 'abort' warn = bval or lval == 'warn' if bval is None and not (warn or abort or lval == 'ignore'): raise error.ConfigError( _("ui.portablefilenames value is invalid ('%s')") % val) return abort, warn class casecollisionauditor(object): def __init__(self, ui, abort, dirstate): self._ui = ui self._abort = abort allfiles = '\0'.join(dirstate._map) self._loweredfiles = set(encoding.lower(allfiles).split('\0')) self._dirstate = dirstate # The purpose of _newfiles is so that we don't complain about # case collisions if someone were to call this object with the # same filename twice. self._newfiles = set() def __call__(self, f): fl = encoding.lower(f) if (fl in self._loweredfiles and f not in self._dirstate and f not in self._newfiles): msg = _('possible case-folding collision for %s') % f if self._abort: raise util.Abort(msg) self._ui.warn(_("warning: %s\n") % msg) self._loweredfiles.add(fl) self._newfiles.add(f) 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 parts[0].lower() in ('.hg', '.hg.', '') or os.pardir in parts): raise util.Abort(_("path contains illegal component: %s") % path) if '.hg' in path.lower(): lparts = [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) class abstractvfs(object): """Abstract base class; cannot be instantiated""" def __init__(self, *args, **kwargs): '''Prevent instantiation; don't call this from subclasses.''' raise NotImplementedError('attempted instantiating ' + str(type(self))) def tryread(self, path): '''gracefully return an empty string for missing files''' try: return self.read(path) except IOError, inst: if inst.errno != errno.ENOENT: raise return "" def read(self, path): fp = self(path, 'rb') try: return fp.read() finally: fp.close() def write(self, path, data): fp = self(path, 'wb') try: return fp.write(data) finally: fp.close() def append(self, path, data): fp = self(path, 'ab') try: return fp.write(data) finally: fp.close() def exists(self, path=None): return os.path.exists(self.join(path)) def isdir(self, path=None): return os.path.isdir(self.join(path)) def makedir(self, path=None, notindexed=True): return util.makedir(self.join(path), notindexed) def makedirs(self, path=None, mode=None): return util.makedirs(self.join(path), mode) def mkdir(self, path=None): return os.mkdir(self.join(path)) def readdir(self, path=None, stat=None, skip=None): return osutil.listdir(self.join(path), stat, skip) def stat(self, path=None): return os.stat(self.join(path)) class vfs(abstractvfs): '''Operate files relative to a base directory This class is used to hide the details of COW semantics and remote file access from higher level code. ''' def __init__(self, base, audit=True, expand=False): if expand: base = os.path.realpath(util.expandpath(base)) self.base = base self._setmustaudit(audit) self.createmode = None self._trustnlink = None def _getmustaudit(self): return self._audit def _setmustaudit(self, onoff): self._audit = onoff if onoff: self.auditor = pathauditor(self.base) else: self.auditor = util.always mustaudit = property(_getmustaudit, _setmustaudit) @util.propertycache def _cansymlink(self): return util.checklink(self.base) def _fixfilemode(self, name): if self.createmode is None: return os.chmod(name, self.createmode & 0666) def __call__(self, path, mode="r", text=False, atomictemp=False): if self._audit: r = util.checkosfilename(path) if r: raise util.Abort("%s: %r" % (r, path)) self.auditor(path) f = self.join(path) if not text and "b" not in mode: mode += "b" # for that other OS nlink = -1 dirname, basename = util.split(f) # If basename is empty, then the path is malformed because it points # to a directory. Let the posixfile() call below raise IOError. if basename and mode not in ('r', 'rb'): if atomictemp: if not os.path.isdir(dirname): util.makedirs(dirname, self.createmode) return util.atomictempfile(f, mode, self.createmode) try: if 'w' in mode: util.unlink(f) nlink = 0 else: # nlinks() may behave differently for files on Windows # shares if the file is open. fd = util.posixfile(f) nlink = util.nlinks(f) if nlink < 1: nlink = 2 # force mktempcopy (issue1922) fd.close() except (OSError, IOError), e: if e.errno != errno.ENOENT: raise nlink = 0 if not os.path.isdir(dirname): util.makedirs(dirname, self.createmode) if nlink > 0: if self._trustnlink is None: self._trustnlink = nlink > 1 or util.checknlink(f) if nlink > 1 or not self._trustnlink: util.rename(util.mktempcopy(f), f) fp = util.posixfile(f, mode) if nlink == 0: self._fixfilemode(f) return fp def symlink(self, src, dst): self.auditor(dst) linkname = self.join(dst) try: os.unlink(linkname) except OSError: pass dirname = os.path.dirname(linkname) if not os.path.exists(dirname): util.makedirs(dirname, self.createmode) if self._cansymlink: try: os.symlink(src, linkname) except OSError, err: raise OSError(err.errno, _('could not symlink to %r: %s') % (src, err.strerror), linkname) else: self.write(dst, src) def audit(self, path): self.auditor(path) def join(self, path): if path: return os.path.join(self.base, path) else: return self.base opener = vfs class auditvfs(object): def __init__(self, vfs): self.vfs = vfs def _getmustaudit(self): return self.vfs.mustaudit def _setmustaudit(self, onoff): self.vfs.mustaudit = onoff mustaudit = property(_getmustaudit, _setmustaudit) class filtervfs(abstractvfs, auditvfs): '''Wrapper vfs for filtering filenames with a function.''' def __init__(self, vfs, filter): auditvfs.__init__(self, vfs) self._filter = filter def __call__(self, path, *args, **kwargs): return self.vfs(self._filter(path), *args, **kwargs) def join(self, path): if path: return self.vfs.join(self._filter(path)) else: return self.vfs.join(path) filteropener = filtervfs 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' % myname) def walkrepos(path, followsym=False, seen_dirs=None, recurse=False): '''yield every hg repository under path, always recursively. The recurse flag will only control recursion into repo working dirs''' def errhandler(err): if err.filename == path: raise err samestat = getattr(os.path, 'samestat', None) if followsym and samestat is not None: def adddir(dirlst, dirname): match = False dirstat = os.stat(dirname) for lstdirstat in dirlst: if samestat(dirstat, lstdirstat): match = True break if not match: dirlst.append(dirstat) return not match else: followsym = False if (seen_dirs is None) and followsym: seen_dirs = [] adddir(seen_dirs, path) for root, dirs, files in os.walk(path, topdown=True, onerror=errhandler): dirs.sort() if '.hg' in dirs: yield root # found a repository qroot = os.path.join(root, '.hg', 'patches') if os.path.isdir(os.path.join(qroot, '.hg')): yield qroot # we have a patch queue repo here if recurse: # avoid recursing inside the .hg directory dirs.remove('.hg') else: dirs[:] = [] # don't descend further elif followsym: newdirs = [] for d in dirs: fname = os.path.join(root, d) if adddir(seen_dirs, fname): if os.path.islink(fname): for hgname in walkrepos(fname, True, seen_dirs): yield hgname else: newdirs.append(d) dirs[:] = newdirs def osrcpath(): '''return default os-specific hgrc search path''' path = systemrcpath() path.extend(userrcpath()) path = [os.path.normpath(f) for f in path] return path _rcpath = None def rcpath(): '''return hgrc search path. if env var HGRCPATH is set, use it. for each item in path, if directory, use files ending in .rc, else use item. make HGRCPATH empty to only look in .hg/hgrc of current repo. if no HGRCPATH, use default os-specific path.''' global _rcpath if _rcpath is None: if 'HGRCPATH' in os.environ: _rcpath = [] for p in os.environ['HGRCPATH'].split(os.pathsep): if not p: continue p = util.expandpath(p) if os.path.isdir(p): for f, kind in osutil.listdir(p): if f.endswith('.rc'): _rcpath.append(os.path.join(p, f)) else: _rcpath.append(p) else: _rcpath = osrcpath() return _rcpath if os.name != 'nt': def rcfiles(path): rcs = [os.path.join(path, 'hgrc')] rcdir = os.path.join(path, 'hgrc.d') try: rcs.extend([os.path.join(rcdir, f) for f, kind in osutil.listdir(rcdir) if f.endswith(".rc")]) except OSError: pass return rcs def systemrcpath(): path = [] if sys.platform == 'plan9': root = 'lib/mercurial' else: root = 'etc/mercurial' # old mod_python does not set sys.argv if len(getattr(sys, 'argv', [])) > 0: p = os.path.dirname(os.path.dirname(sys.argv[0])) path.extend(rcfiles(os.path.join(p, root))) path.extend(rcfiles('/' + root)) return path def userrcpath(): if sys.platform == 'plan9': return [os.environ['home'] + '/lib/hgrc'] else: return [os.path.expanduser('~/.hgrc')] else: import _winreg def systemrcpath(): '''return default os-specific hgrc search path''' rcpath = [] filename = util.executablepath() # Use mercurial.ini found in directory with hg.exe progrc = os.path.join(os.path.dirname(filename), 'mercurial.ini') if os.path.isfile(progrc): rcpath.append(progrc) return rcpath # Use hgrc.d found in directory with hg.exe progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d') if os.path.isdir(progrcd): for f, kind in osutil.listdir(progrcd): if f.endswith('.rc'): rcpath.append(os.path.join(progrcd, f)) return rcpath # else look for a system rcpath in the registry value = util.lookupreg('SOFTWARE\\Mercurial', None, _winreg.HKEY_LOCAL_MACHINE) if not isinstance(value, str) or not value: return rcpath value = util.localpath(value) for p in value.split(os.pathsep): if p.lower().endswith('mercurial.ini'): rcpath.append(p) elif os.path.isdir(p): for f, kind in osutil.listdir(p): if f.endswith('.rc'): rcpath.append(os.path.join(p, f)) return rcpath def userrcpath(): '''return os-specific hgrc search path to the user dir''' home = os.path.expanduser('~') path = [os.path.join(home, 'mercurial.ini'), os.path.join(home, '.hgrc')] userprofile = os.environ.get('USERPROFILE') if userprofile: path.append(os.path.join(userprofile, 'mercurial.ini')) path.append(os.path.join(userprofile, '.hgrc')) return path def revsingle(repo, revspec, default='.'): if not revspec: return repo[default] l = revrange(repo, [revspec]) if len(l) < 1: raise util.Abort(_('empty revision set')) return repo[l[-1]] def revpair(repo, revs): if not revs: return repo.dirstate.p1(), None l = revrange(repo, revs) if len(l) == 0: if revs: raise util.Abort(_('empty revision range')) return repo.dirstate.p1(), None if len(l) == 1 and len(revs) == 1 and _revrangesep not in revs[0]: return repo.lookup(l[0]), None return repo.lookup(l[0]), repo.lookup(l[-1]) _revrangesep = ':' def revrange(repo, revs): """Yield revision as strings from a list of revision specifications.""" def revfix(repo, val, defval): if not val and val != 0 and defval is not None: return defval return repo[val].rev() seen, l = set(), [] for spec in revs: if l and not seen: seen = set(l) # attempt to parse old-style ranges first to deal with # things like old-tag which contain query metacharacters try: if isinstance(spec, int): seen.add(spec) l.append(spec) continue if _revrangesep in spec: start, end = spec.split(_revrangesep, 1) start = revfix(repo, start, 0) end = revfix(repo, end, len(repo) - 1) step = start > end and -1 or 1 if not seen and not l: # by far the most common case: revs = ["-1:0"] l = range(start, end + step, step) # defer syncing seen until next iteration continue newrevs = set(xrange(start, end + step, step)) if seen: newrevs.difference_update(seen) seen.update(newrevs) else: seen = newrevs l.extend(sorted(newrevs, reverse=start > end)) continue elif spec and spec in repo: # single unquoted rev rev = revfix(repo, spec, None) if rev in seen: continue seen.add(rev) l.append(rev) continue except error.RepoLookupError: pass # fall through to new-style queries if old-style fails m = revset.match(repo.ui, spec) dl = [r for r in m(repo, list(repo)) if r not in seen] l.extend(dl) seen.update(dl) return l def expandpats(pats): if not util.expandglobs: return list(pats) ret = [] for p in pats: kind, name = matchmod._patsplit(p, None) if kind is None: try: globbed = glob.glob(name) except re.error: globbed = [name] if globbed: ret.extend(globbed) continue ret.append(p) return ret def matchandpats(ctx, pats=[], opts={}, globbed=False, default='relpath'): if pats == ("",): pats = [] if not globbed and default == 'relpath': pats = expandpats(pats or []) m = ctx.match(pats, opts.get('include'), opts.get('exclude'), default) def badfn(f, msg): ctx._repo.ui.warn("%s: %s\n" % (m.rel(f), msg)) m.bad = badfn return m, pats def match(ctx, pats=[], opts={}, globbed=False, default='relpath'): return matchandpats(ctx, pats, opts, globbed, default)[0] def matchall(repo): return matchmod.always(repo.root, repo.getcwd()) def matchfiles(repo, files): return matchmod.exact(repo.root, repo.getcwd(), files) def addremove(repo, pats=[], opts={}, dry_run=None, similarity=None): if dry_run is None: dry_run = opts.get('dry_run') if similarity is None: similarity = float(opts.get('similarity') or 0) # we'd use status here, except handling of symlinks and ignore is tricky added, unknown, deleted, removed = [], [], [], [] audit_path = pathauditor(repo.root) m = match(repo[None], pats, opts) rejected = [] m.bad = lambda x, y: rejected.append(x) for abs in repo.walk(m): target = repo.wjoin(abs) good = True try: audit_path(abs) except (OSError, util.Abort): good = False rel = m.rel(abs) exact = m.exact(abs) if good and abs not in repo.dirstate: unknown.append(abs) if repo.ui.verbose or not exact: repo.ui.status(_('adding %s\n') % ((pats and rel) or abs)) elif (repo.dirstate[abs] != 'r' and (not good or not os.path.lexists(target) or (os.path.isdir(target) and not os.path.islink(target)))): deleted.append(abs) if repo.ui.verbose or not exact: repo.ui.status(_('removing %s\n') % ((pats and rel) or abs)) # for finding renames elif repo.dirstate[abs] == 'r': removed.append(abs) elif repo.dirstate[abs] == 'a': added.append(abs) copies = {} if similarity > 0: for old, new, score in similar.findrenames(repo, added + unknown, removed + deleted, similarity): if repo.ui.verbose or not m.exact(old) or not m.exact(new): repo.ui.status(_('recording removal of %s as rename to %s ' '(%d%% similar)\n') % (m.rel(old), m.rel(new), score * 100)) copies[new] = old if not dry_run: wctx = repo[None] wlock = repo.wlock() try: wctx.forget(deleted) wctx.add(unknown) for new, old in copies.iteritems(): wctx.copy(old, new) finally: wlock.release() for f in rejected: if f in m.files(): return 1 return 0 def updatedir(ui, repo, patches, similarity=0): '''Update dirstate after patch application according to metadata''' if not patches: return [] copies = [] removes = set() cfiles = patches.keys() cwd = repo.getcwd() if cwd: cfiles = [util.pathto(repo.root, cwd, f) for f in patches.keys()] for f in patches: gp = patches[f] if not gp: continue if gp.op == 'RENAME': copies.append((gp.oldpath, gp.path)) removes.add(gp.oldpath) elif gp.op == 'COPY': copies.append((gp.oldpath, gp.path)) elif gp.op == 'DELETE': removes.add(gp.path) wctx = repo[None] for src, dst in copies: dirstatecopy(ui, repo, wctx, src, dst, cwd=cwd) if (not similarity) and removes: wctx.remove(sorted(removes), True) for f in patches: gp = patches[f] if gp and gp.mode: islink, isexec = gp.mode dst = repo.wjoin(gp.path) # patch won't create empty files if gp.op == 'ADD' and not os.path.lexists(dst): flags = (isexec and 'x' or '') + (islink and 'l' or '') repo.wwrite(gp.path, '', flags) util.setflags(dst, islink, isexec) addremove(repo, cfiles, similarity=similarity) files = patches.keys() files.extend([r for r in removes if r not in files]) return sorted(files) def dirstatecopy(ui, repo, wctx, src, dst, dryrun=False, cwd=None): """Update the dirstate to reflect the intent of copying src to dst. For different reasons it might not end with dst being marked as copied from src. """ origsrc = repo.dirstate.copied(src) or src if dst == origsrc: # copying back a copy? if repo.dirstate[dst] not in 'mn' and not dryrun: repo.dirstate.normallookup(dst) else: if repo.dirstate[origsrc] == 'a' and origsrc == src: if not ui.quiet: ui.warn(_("%s has not been committed yet, so no copy " "data will be stored for %s.\n") % (repo.pathto(origsrc, cwd), repo.pathto(dst, cwd))) if repo.dirstate[dst] in '?r' and not dryrun: wctx.add([dst]) elif not dryrun: wctx.copy(origsrc, dst) def readrequires(opener, supported): '''Reads and parses .hg/requires and checks if all entries found are in the list of supported features.''' requirements = set(opener.read("requires").splitlines()) missings = [] for r in requirements: if r not in supported: if not r or not r[0].isalnum(): raise error.RequirementError(_(".hg/requires file is corrupt")) missings.append(r) missings.sort() if missings: raise error.RequirementError( _("unknown repository format: requires features '%s' (upgrade " "Mercurial)") % "', '".join(missings)) return requirements class filecacheentry(object): def __init__(self, path): self.path = path self.cachestat = filecacheentry.stat(self.path) if self.cachestat: self._cacheable = self.cachestat.cacheable() else: # None means we don't know yet self._cacheable = None def refresh(self): if self.cacheable(): self.cachestat = filecacheentry.stat(self.path) def cacheable(self): if self._cacheable is not None: return self._cacheable # we don't know yet, assume it is for now return True def changed(self): # no point in going further if we can't cache it if not self.cacheable(): return True newstat = filecacheentry.stat(self.path) # we may not know if it's cacheable yet, check again now if newstat and self._cacheable is None: self._cacheable = newstat.cacheable() # check again if not self._cacheable: return True if self.cachestat != newstat: self.cachestat = newstat return True else: return False @staticmethod def stat(path): try: return util.cachestat(path) except OSError, e: if e.errno != errno.ENOENT: raise class filecache(object): '''A property like decorator that tracks a file under .hg/ for updates. Records stat info when called in _filecache. On subsequent calls, compares old stat info with new info, and recreates the object when needed, updating the new stat info in _filecache. Mercurial either atomic renames or appends for files under .hg, so to ensure the cache is reliable we need the filesystem to be able to tell us if a file has been replaced. If it can't, we fallback to recreating the object on every call (essentially the same behaviour as propertycache).''' def __init__(self, path): self.path = path def join(self, obj, fname): """Used to compute the runtime path of the cached file. Users should subclass filecache and provide their own version of this function to call the appropriate join function on 'obj' (an instance of the class that its member function was decorated). """ return obj.join(fname) def __call__(self, func): self.func = func self.name = func.__name__ return self def __get__(self, obj, type=None): # do we need to check if the file changed? if self.name in obj.__dict__: return obj.__dict__[self.name] entry = obj._filecache.get(self.name) if entry: if entry.changed(): entry.obj = self.func(obj) else: path = self.join(obj, self.path) # We stat -before- creating the object so our cache doesn't lie if # a writer modified between the time we read and stat entry = filecacheentry(path) entry.obj = self.func(obj) obj._filecache[self.name] = entry obj.__dict__[self.name] = entry.obj return entry.obj def __set__(self, obj, value): if self.name in obj._filecache: obj._filecache[self.name].obj = value # update cached copy obj.__dict__[self.name] = value # update copy returned by obj.x def __delete__(self, obj): try: del obj.__dict__[self.name] except KeyError: raise AttributeError, self.name