Mercurial > hg
view mercurial/statichttprepo.py @ 23201:7e97bf6ee2d6
changelog: rework the delayupdate mechanism
The current way we use the 'delayupdate' mechanism is wrong. We call
'delayupdate' right after the transaction retrieval, then we call 'finalize'
right before calling 'tr.close()'. The 'finalize' call will -always- result in a
flush to disk, making the data available to all readers. But the 'tr.close()' may
be a no-op if the transaction is nested. This would result in data:
1) exposed to reader too early,
2) rolled back by other part of the transaction after such exposure
So we need to end up in a situation where we call 'finalize' a single time when
the transaction actually closes. For this purpose we need to be able to call
'delayupdate' and '_writepending' multiple times and 'finalize' once. This was
not possible with the previous state of the code.
This changeset refactors the code to makes this possible. We buffer data in memory
as much as possible and fall-back to writing to a ".a" file after the first call
to '_writepending'.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
---|---|
date | Sat, 18 Oct 2014 01:12:18 -0700 |
parents | af4158b8876b |
children | 72319005f5fb |
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# statichttprepo.py - simple http repository class for mercurial # # This provides read-only repo access to repositories exported via static http # # Copyright 2005-2007 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 changelog, byterange, url, error import localrepo, manifest, util, scmutil, store import urllib, urllib2, errno, os class httprangereader(object): def __init__(self, url, opener): # we assume opener has HTTPRangeHandler self.url = url self.pos = 0 self.opener = opener self.name = url def seek(self, pos): self.pos = pos def read(self, bytes=None): req = urllib2.Request(self.url) end = '' if bytes: end = self.pos + bytes - 1 if self.pos or end: req.add_header('Range', 'bytes=%d-%s' % (self.pos, end)) try: f = self.opener.open(req) data = f.read() # Python 2.6+ defines a getcode() function, and 2.4 and # 2.5 appear to always have an undocumented code attribute # set. If we can't read either of those, fall back to 206 # and hope for the best. code = getattr(f, 'getcode', lambda : getattr(f, 'code', 206))() except urllib2.HTTPError, inst: num = inst.code == 404 and errno.ENOENT or None raise IOError(num, inst) except urllib2.URLError, inst: raise IOError(None, inst.reason[1]) if code == 200: # HTTPRangeHandler does nothing if remote does not support # Range headers and returns the full entity. Let's slice it. if bytes: data = data[self.pos:self.pos + bytes] else: data = data[self.pos:] elif bytes: data = data[:bytes] self.pos += len(data) return data def readlines(self): return self.read().splitlines(True) def __iter__(self): return iter(self.readlines()) def close(self): pass def build_opener(ui, authinfo): # urllib cannot handle URLs with embedded user or passwd urlopener = url.opener(ui, authinfo) urlopener.add_handler(byterange.HTTPRangeHandler()) class statichttpvfs(scmutil.abstractvfs): def __init__(self, base): self.base = base def __call__(self, path, mode="r", atomictemp=None): if mode not in ('r', 'rb'): raise IOError('Permission denied') f = "/".join((self.base, urllib.quote(path))) return httprangereader(f, urlopener) def join(self, path): if path: return os.path.join(self.base, path) else: return self.base return statichttpvfs class statichttppeer(localrepo.localpeer): def local(self): return None def canpush(self): return False class statichttprepository(localrepo.localrepository): supported = localrepo.localrepository._basesupported def __init__(self, ui, path): self._url = path self.ui = ui self.root = path u = util.url(path.rstrip('/') + "/.hg") self.path, authinfo = u.authinfo() opener = build_opener(ui, authinfo) self.opener = opener(self.path) self.vfs = self.opener self._phasedefaults = [] try: requirements = scmutil.readrequires(self.opener, self.supported) except IOError, inst: if inst.errno != errno.ENOENT: raise requirements = set() # check if it is a non-empty old-style repository try: fp = self.opener("00changelog.i") fp.read(1) fp.close() except IOError, inst: if inst.errno != errno.ENOENT: raise # we do not care about empty old-style repositories here msg = _("'%s' does not appear to be an hg repository") % path raise error.RepoError(msg) # setup store self.store = store.store(requirements, self.path, opener) self.spath = self.store.path self.sopener = self.store.opener self.svfs = self.sopener self.sjoin = self.store.join self._filecache = {} self.requirements = requirements self.manifest = manifest.manifest(self.sopener) self.changelog = changelog.changelog(self.sopener) self._tags = None self.nodetagscache = None self._branchcaches = {} self.encodepats = None self.decodepats = None def _restrictcapabilities(self, caps): caps = super(statichttprepository, self)._restrictcapabilities(caps) return caps.difference(["pushkey"]) def url(self): return self._url def local(self): return False def peer(self): return statichttppeer(self) def lock(self, wait=True): raise util.Abort(_('cannot lock static-http repository')) def instance(ui, path, create): if create: raise util.Abort(_('cannot create new static-http repository')) return statichttprepository(ui, path[7:])