Mercurial > hg
view hgext/fsmonitor/state.py @ 38717:aa21a9ad46ea
sparse-revlog: new requirement enabled with format.sparse-revlog
The meaning of the new 'sparse-revlog' requirement is that the revlogs are
allowed to contain wider delta chains with larger holes between the interesting
chunks. These sparse delta chains should be read in several chunks to avoid a
potential explosion of memory usage.
Former version won't know how to read a delta chain in several chunks. They
would keep reading them in a single read, and therefore would be subject to the
potential memory explosion. Hence this new requirement: only versions having
support of sparse-revlog reading should be allowed to read such a revlog.
Implementation of this new algorithm and tools to enable or disable the
requirement will follow in the next changesets.
author | Paul Morelle <paul.morelle@octobus.net> |
---|---|
date | Mon, 04 Jun 2018 22:23:18 +0200 |
parents | 718f7acd6d5e |
children | 2372284d9457 |
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# state.py - fsmonitor persistent state # # Copyright 2013-2016 Facebook, Inc. # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import errno import os import socket import struct from mercurial.i18n import _ from mercurial import ( pathutil, util, ) _version = 4 _versionformat = ">I" class state(object): def __init__(self, repo): self._vfs = repo.vfs self._ui = repo.ui self._rootdir = pathutil.normasprefix(repo.root) self._lastclock = None self._identity = util.filestat(None) self.mode = self._ui.config('fsmonitor', 'mode') self.walk_on_invalidate = self._ui.configbool( 'fsmonitor', 'walk_on_invalidate') self.timeout = float(self._ui.config('fsmonitor', 'timeout')) def get(self): try: file = self._vfs('fsmonitor.state', 'rb') except IOError as inst: self._identity = util.filestat(None) if inst.errno != errno.ENOENT: raise return None, None, None self._identity = util.filestat.fromfp(file) versionbytes = file.read(4) if len(versionbytes) < 4: self._ui.log( 'fsmonitor', 'fsmonitor: state file only has %d bytes, ' 'nuking state\n' % len(versionbytes)) self.invalidate() return None, None, None try: diskversion = struct.unpack(_versionformat, versionbytes)[0] if diskversion != _version: # different version, nuke state and start over self._ui.log( 'fsmonitor', 'fsmonitor: version switch from %d to ' '%d, nuking state\n' % (diskversion, _version)) self.invalidate() return None, None, None state = file.read().split('\0') # state = hostname\0clock\0ignorehash\0 + list of files, each # followed by a \0 if len(state) < 3: self._ui.log( 'fsmonitor', 'fsmonitor: state file truncated (expected ' '3 chunks, found %d), nuking state\n', len(state)) self.invalidate() return None, None, None diskhostname = state[0] hostname = socket.gethostname() if diskhostname != hostname: # file got moved to a different host self._ui.log('fsmonitor', 'fsmonitor: stored hostname "%s" ' 'different from current "%s", nuking state\n' % (diskhostname, hostname)) self.invalidate() return None, None, None clock = state[1] ignorehash = state[2] # discard the value after the last \0 notefiles = state[3:-1] finally: file.close() return clock, ignorehash, notefiles def set(self, clock, ignorehash, notefiles): if clock is None: self.invalidate() return # Read the identity from the file on disk rather than from the open file # pointer below, because the latter is actually a brand new file. identity = util.filestat.frompath(self._vfs.join('fsmonitor.state')) if identity != self._identity: self._ui.debug('skip updating fsmonitor.state: identity mismatch\n') return try: file = self._vfs('fsmonitor.state', 'wb', atomictemp=True, checkambig=True) except (IOError, OSError): self._ui.warn(_("warning: unable to write out fsmonitor state\n")) return with file: file.write(struct.pack(_versionformat, _version)) file.write(socket.gethostname() + '\0') file.write(clock + '\0') file.write(ignorehash + '\0') if notefiles: file.write('\0'.join(notefiles)) file.write('\0') def invalidate(self): try: os.unlink(os.path.join(self._rootdir, '.hg', 'fsmonitor.state')) except OSError as inst: if inst.errno != errno.ENOENT: raise self._identity = util.filestat(None) def setlastclock(self, clock): self._lastclock = clock def getlastclock(self): return self._lastclock