Mercurial > hg
view mercurial/repocache.py @ 44202:a7f8160cc4e4
setup: don't skip the search for global hg.exe if there is no local instance
The point of trying not to blindly execute `hg` on Windows is that the local
hg.exe would be given precedence, and if py3 isn't on PATH, it errors out with a
modal dialog. But that's not a problem if there is no local executable that
could be run.
The problem that I recently ran into was I upgraded the repo format to use zstd.
But doing a `make clean` deletes all of the supporting libraries, causing the
next run to abort with a message about not understanding the
`revlog-compression-zstd` requirement. By getting rid of the local executable
in the previous commit when cleaning, we avoid leaving a broken executable
around, and avoid the py3 PATH problem too. There is still a small hole in that
`hg.exe` needs to be deleted before switching between py2/py3/PyOxidizer builds,
because the zstd module won't load. But that seems like good hygiene anyway.
Differential Revision: https://phab.mercurial-scm.org/D8038
author | Matt Harbison <matt_harbison@yahoo.com> |
---|---|
date | Tue, 28 Jan 2020 22:27:30 -0500 |
parents | 8ff1ecfadcd1 |
children | 6000f5b25c9b |
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# repocache.py - in-memory repository cache for long-running services # # Copyright 2018 Yuya Nishihara <yuya@tcha.org> # # 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 collections import gc import threading from . import ( error, hg, obsolete, scmutil, util, ) class repoloader(object): """Load repositories in background thread This is designed for a forking server. A cached repo cannot be obtained until the server fork()s a worker and the loader thread stops. """ def __init__(self, ui, maxlen): self._ui = ui.copy() self._cache = util.lrucachedict(max=maxlen) # use deque and Event instead of Queue since deque can discard # old items to keep at most maxlen items. self._inqueue = collections.deque(maxlen=maxlen) self._accepting = False self._newentry = threading.Event() self._thread = None def start(self): assert not self._thread if self._inqueue.maxlen == 0: # no need to spawn loader thread as the cache is disabled return self._accepting = True self._thread = threading.Thread(target=self._mainloop) self._thread.start() def stop(self): if not self._thread: return self._accepting = False self._newentry.set() self._thread.join() self._thread = None self._cache.clear() self._inqueue.clear() def load(self, path): """Request to load the specified repository in background""" self._inqueue.append(path) self._newentry.set() def get(self, path): """Return a cached repo if available This function must be called after fork(), where the loader thread is stopped. Otherwise, the returned repo might be updated by the loader thread. """ if self._thread and self._thread.is_alive(): raise error.ProgrammingError( b'cannot obtain cached repo while loader is active' ) return self._cache.peek(path, None) def _mainloop(self): while self._accepting: # Avoid heavy GC after fork(), which would cancel the benefit of # COW. We assume that GIL is acquired while GC is underway in the # loader thread. If that isn't true, we might have to move # gc.collect() to the main thread so that fork() would never stop # the thread where GC is in progress. gc.collect() self._newentry.wait() while self._accepting: self._newentry.clear() try: path = self._inqueue.popleft() except IndexError: break scmutil.callcatch(self._ui, lambda: self._load(path)) def _load(self, path): start = util.timer() # TODO: repo should be recreated if storage configuration changed try: # pop before loading so inconsistent state wouldn't be exposed repo = self._cache.pop(path) except KeyError: repo = hg.repository(self._ui, path).unfiltered() _warmupcache(repo) repo.ui.log( b'repocache', b'loaded repo into cache: %s (in %.3fs)\n', path, util.timer() - start, ) self._cache.insert(path, repo) # TODO: think about proper API of preloading cache def _warmupcache(repo): repo.invalidateall() repo.changelog repo.obsstore._all repo.obsstore.successors repo.obsstore.predecessors repo.obsstore.children for name in obsolete.cachefuncs: obsolete.getrevs(repo, name) repo._phasecache.loadphaserevs(repo) # TODO: think about proper API of attaching preloaded attributes def copycache(srcrepo, destrepo): """Copy cached attributes from srcrepo to destrepo""" destfilecache = destrepo._filecache srcfilecache = srcrepo._filecache if b'changelog' in srcfilecache: destfilecache[b'changelog'] = ce = srcfilecache[b'changelog'] ce.obj.opener = ce.obj._realopener = destrepo.svfs if b'obsstore' in srcfilecache: destfilecache[b'obsstore'] = ce = srcfilecache[b'obsstore'] ce.obj.svfs = destrepo.svfs if b'_phasecache' in srcfilecache: destfilecache[b'_phasecache'] = ce = srcfilecache[b'_phasecache'] ce.obj.opener = destrepo.svfs