Mercurial > hg
view mercurial/statichttprepo.py @ 39314:7f5e6d3e9032
manifest: proxy to revlog instance instead of inheriting
Previously, manifestrevlog inherited revlog.revlog and therefore
exposed all its APIs. This inevitably resulted in consumers calling
low-level revlog APIs.
As part of abstracting storage, we want to formalize the interface
for manifest storage. The revlog API is much too large to define as
the interface.
Like we did for filelog, this commit divorces the manifest class
from revlog so that we can standardize on a smaller API surface.
The way I went about this commit was I broke the inheritance, ran
tests, and added proxies until all tests passed. Like filelog, there
are a handful of attributes that don't belong on the interface.
And like filelog, we'll tease these out in the future.
As part of this, we formalize an interface for manifest storage and
add checks that manifestrevlog conforms to the interface.
Adding proxies will introduce some overhead due to extra attribute
lookups and function calls. On the mozilla-unified repository:
$ hg verify
before: real 627.220 secs (user 525.870+0.000 sys 18.800+0.000)
after: real 628.930 secs (user 532.050+0.000 sys 18.320+0.000)
$ hg serve (for a clone)
before: user 223.580+0.000 sys 14.270+0.000
after: user 227.720+0.000 sys 13.920+0.000
$ hg clone
before: user 506.390+0.000 sys 29.720+0.000
after: user 513.080+0.000 sys 28.280+0.000
There appears to be some overhead here. But it appears to be 1-2%.
I think that is an appropriate price to pay for storage abstraction,
which will eventually let us have much nicer things. If the overhead
is noticed in other operations (whose CPU time isn't likely dwarfed by
fulltext resolution) or if we want to cut down on the overhead, we
could dynamically build up a type whose methods are effectively
aliased to a revlog instance's. I'm inclined to punt on that problem
for now. We may have to do it for the changelog. At which point it
could be implemented in a generic way and ported to filelog and
manifestrevlog easily enough I would think.
.. api:: manifest.manifestrevlog no longer inherits from revlog
The manifestrevlog class now wraps a revlog instance instead of
inheriting from revlog. Various attributes and methods on instances
are no longer available.
Differential Revision: https://phab.mercurial-scm.org/D4386
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Mon, 27 Aug 2018 10:15:15 -0700 |
parents | 0664be4f0c1f |
children | 089fc0db0954 |
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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 __future__ import absolute_import import errno from .i18n import _ from . import ( changelog, error, localrepo, manifest, namespaces, pathutil, scmutil, store, url, util, vfs as vfsmod, ) urlerr = util.urlerr urlreq = util.urlreq 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 __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.close() def seek(self, pos): self.pos = pos def read(self, bytes=None): req = urlreq.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() code = f.code except urlerr.httperror as inst: num = inst.code == 404 and errno.ENOENT or None raise IOError(num, inst) except urlerr.urlerror as 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 # _RangeError and _HTTPRangeHandler were originally in byterange.py, # which was itself extracted from urlgrabber. See the last version of # byterange.py from history if you need more information. class _RangeError(IOError): """Error raised when an unsatisfiable range is requested.""" class _HTTPRangeHandler(urlreq.basehandler): """Handler that enables HTTP Range headers. This was extremely simple. The Range header is a HTTP feature to begin with so all this class does is tell urllib2 that the "206 Partial Content" response from the HTTP server is what we expected. """ def http_error_206(self, req, fp, code, msg, hdrs): # 206 Partial Content Response r = urlreq.addinfourl(fp, hdrs, req.get_full_url()) r.code = code r.msg = msg return r def http_error_416(self, req, fp, code, msg, hdrs): # HTTP's Range Not Satisfiable error raise _RangeError('Requested Range Not Satisfiable') def build_opener(ui, authinfo): # urllib cannot handle URLs with embedded user or passwd urlopener = url.opener(ui, authinfo) urlopener.add_handler(_HTTPRangeHandler()) class statichttpvfs(vfsmod.abstractvfs): def __init__(self, base): self.base = base def __call__(self, path, mode='r', *args, **kw): if mode not in ('r', 'rb'): raise IOError('Permission denied') f = "/".join((self.base, urlreq.quote(path))) return httprangereader(f, urlopener) def join(self, path): if path: return pathutil.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() vfsclass = build_opener(ui, authinfo) self.vfs = vfsclass(self.path) self.cachevfs = vfsclass(self.vfs.join('cache')) self._phasedefaults = [] self.names = namespaces.namespaces() self.filtername = None try: requirements = scmutil.readrequires(self.vfs, self.supported) except IOError as inst: if inst.errno != errno.ENOENT: raise requirements = set() # check if it is a non-empty old-style repository try: fp = self.vfs("00changelog.i") fp.read(1) fp.close() except IOError as 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, vfsclass) self.spath = self.store.path self.svfs = self.store.opener self.sjoin = self.store.join self._filecache = {} self.requirements = requirements self.manifestlog = manifest.manifestlog(self.svfs, self) self.changelog = changelog.changelog(self.svfs) self._tags = None self.nodetagscache = None self._branchcaches = {} self._revbranchcache = None self.encodepats = None self.decodepats = None self._transref = 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 wlock(self, wait=True): raise error.LockUnavailable(0, _('lock not available'), 'lock', _('cannot lock static-http repository')) def lock(self, wait=True): raise error.Abort(_('cannot lock static-http repository')) def _writecaches(self): pass # statichttprepository are read only def instance(ui, path, create, intents=None): if create: raise error.Abort(_('cannot create new static-http repository')) return statichttprepository(ui, path[7:])