hg: make cachedlocalrepo cache appropriate repoview object
Before this patch, 'cachedlocalrepo' always caches "visible" repoview
object, because 'cachedlocalrepo' uses "visible" repoview returned by
'hg.repository()' without any additional processing.
If the client of 'cachedlocalrepo' wants "served" repoview, some
objects to be cached are discarded unintentionally.
1. 'cachedlocalrepo' newly caches "visible" repoview object
(call it VIEW1)
2. 'cachedlocalrepo' returns VIEW1 to the client of it at 'fetch()'
3. the client gets "served" repoview object by 'filtered("served")'
on VIEW1 (call this "served" repoview VIEW2)
4. accessing to 'repo.changelog' implies:
- instantiation of changelog via 'localrepository.changelog'
- instantiation of "filtered changelog" via 'repoview.changelog'
5. "filtered changelog" above is cached in VIEW2
6. VIEW2 is discarded after processing, because there is no
reference to it
7. 'cachedlocalrepo' returns VIEW1 cached at (1) above to the
client at next 'fetch()'
8. 'filtered("served")' on VIEW1 at the client side creates new
"served" repoview again, because VIEW1 is "visible"
(call this new "served" repoview VIEW3)
9. accessing to 'repo.changelog' implies instantiation of filtered
changelog again, because "filtered changelog" is cached in
VIEW2 at (5), but not in VIEW3 currently used
10. (go to (7) above)
As described above, "served" repoview object and "filtered changelog"
cached in it are discarded always, even if the repository itself
hasn't been changed since last access.
For example, in the case of 'hgweb_mod.hgweb', "newly caching" occurs,
when:
- all cached objects are already assigned to another threads
(in this case, repoview is created in 'cachedlocalrepo.copy()')
- or, stat of '00changelog.i' is changed from last access
(in this case, repoview is created in 'cachedlocalrepo.fetch()')
once changes are pushed via HTTP, this always occurs.
The root cause of this inefficiency is that 'cachedlocalrepo' always
caches "visible" repoview object, even if the client of it wants
another view.
To make 'cachedlocalrepo' cache appropriate repoview object, this
patch adds additional filtering on the repo object returned by
'hg.repository()'. It is assumed that initial repoview object should
be already filtered by expected view.
After this patch:
- 'filtered("served")' on VIEW1 at (3)/(7) above returns VIEW1
itself, because VIEW1 is now "served", and
- VIEW2 and VIEW3 equal VIEW1
- therefore, "filtered changelog" is cached in VIEW1, and reused
intentionally
# 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
import os
import urllib
import urllib2
from .i18n import _
from . import (
byterange,
changelog,
error,
localrepo,
manifest,
namespaces,
scmutil,
store,
url,
util,
)
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 = 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()
code = f.code
except urllib2.HTTPError as inst:
num = inst.code == 404 and errno.ENOENT or None
raise IOError(num, inst)
except urllib2.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
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', *args, **kw):
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 = []
self.names = namespaces.namespaces()
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, opener)
self.spath = self.store.path
self.svfs = self.store.opener
self.sjoin = self.store.join
self._filecache = {}
self.requirements = requirements
self.manifest = manifest.manifest(self.svfs)
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 lock(self, wait=True):
raise error.Abort(_('cannot lock static-http repository'))
def instance(ui, path, create):
if create:
raise error.Abort(_('cannot create new static-http repository'))
return statichttprepository(ui, path[7:])