changegroup: capture revision delta in a data structure
The current changegroup generation code is tightly coupled to
the revlog API. This tight coupling makes it difficult to implement
alternate storage backends without requiring a large surface area
of the revlog API to be exposed. This is not desirable.
In order to support changegroup generation with non-revlog storage,
we'll need to abstract the concept of delta generation.
This commit is the first step down that road. We introduce a
data structure for representing a delta in a changegroup.
The API still leaves a lot to be desired. But at least we now
have separation between data and actions performed on it.
As part of this, we tweak behavior slightly: we no longer
concatenate the delta prefix with the metadata header. Instead,
we track and emit the prefix as a separate chunk. This shouldn't
have any meaningful impact since all the chunks just get sent to
the wire, the compressor, etc.
Because we're introducing a new object, this does add some
overhead to changegroup execution. `hg perfchangegroupchangelog`
on my clone of the Mercurial repo (~40,000 visible revisions in
the changelog) slows down a bit:
! wall 1.268600 comb 1.270000 user 1.270000 sys 0.000000 (best of 8)
! wall 1.419479 comb 1.410000 user 1.410000 sys 0.000000 (best of 8)
With for `hg bundle -t none-v2 -a /dev/null`:
before: real 6.610 secs (user 6.460+0.000 sys 0.140+0.000)
after: real 7.210 secs (user 7.060+0.000 sys 0.140+0.000)
I plan to claw back this regression in future commits. And I may
even do away with this data structure once the refactor is complete.
For now, it makes things easier to comprehend.
Differential Revision: https://phab.mercurial-scm.org/D4075
# hgweb/hgweb_mod.py - Web interface for a repository.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>
# 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 contextlib
import os
from .common import (
ErrorResponse,
HTTP_BAD_REQUEST,
cspvalues,
permhooks,
statusmessage,
)
from .. import (
encoding,
error,
formatter,
hg,
hook,
profiling,
pycompat,
registrar,
repoview,
templatefilters,
templater,
templateutil,
ui as uimod,
util,
wireprotoserver,
)
from . import (
request as requestmod,
webcommands,
webutil,
wsgicgi,
)
def getstyle(req, configfn, templatepath):
styles = (
req.qsparams.get('style', None),
configfn('web', 'style'),
'paper',
)
return styles, templater.stylemap(styles, templatepath)
def makebreadcrumb(url, prefix=''):
'''Return a 'URL breadcrumb' list
A 'URL breadcrumb' is a list of URL-name pairs,
corresponding to each of the path items on a URL.
This can be used to create path navigation entries.
'''
if url.endswith('/'):
url = url[:-1]
if prefix:
url = '/' + prefix + url
relpath = url
if relpath.startswith('/'):
relpath = relpath[1:]
breadcrumb = []
urlel = url
pathitems = [''] + relpath.split('/')
for pathel in reversed(pathitems):
if not pathel or not urlel:
break
breadcrumb.append({'url': urlel, 'name': pathel})
urlel = os.path.dirname(urlel)
return templateutil.mappinglist(reversed(breadcrumb))
class requestcontext(object):
"""Holds state/context for an individual request.
Servers can be multi-threaded. Holding state on the WSGI application
is prone to race conditions. Instances of this class exist to hold
mutable and race-free state for requests.
"""
def __init__(self, app, repo, req, res):
self.repo = repo
self.reponame = app.reponame
self.req = req
self.res = res
self.maxchanges = self.configint('web', 'maxchanges')
self.stripecount = self.configint('web', 'stripes')
self.maxshortchanges = self.configint('web', 'maxshortchanges')
self.maxfiles = self.configint('web', 'maxfiles')
self.allowpull = self.configbool('web', 'allow-pull')
# we use untrusted=False to prevent a repo owner from using
# web.templates in .hg/hgrc to get access to any file readable
# by the user running the CGI script
self.templatepath = self.config('web', 'templates', untrusted=False)
# This object is more expensive to build than simple config values.
# It is shared across requests. The app will replace the object
# if it is updated. Since this is a reference and nothing should
# modify the underlying object, it should be constant for the lifetime
# of the request.
self.websubtable = app.websubtable
self.csp, self.nonce = cspvalues(self.repo.ui)
# Trust the settings from the .hg/hgrc files by default.
def config(self, section, name, default=uimod._unset, untrusted=True):
return self.repo.ui.config(section, name, default,
untrusted=untrusted)
def configbool(self, section, name, default=uimod._unset, untrusted=True):
return self.repo.ui.configbool(section, name, default,
untrusted=untrusted)
def configint(self, section, name, default=uimod._unset, untrusted=True):
return self.repo.ui.configint(section, name, default,
untrusted=untrusted)
def configlist(self, section, name, default=uimod._unset, untrusted=True):
return self.repo.ui.configlist(section, name, default,
untrusted=untrusted)
def archivelist(self, nodeid):
return webutil.archivelist(self.repo.ui, nodeid)
def templater(self, req):
# determine scheme, port and server name
# this is needed to create absolute urls
logourl = self.config('web', 'logourl')
logoimg = self.config('web', 'logoimg')
staticurl = (self.config('web', 'staticurl')
or req.apppath.rstrip('/') + '/static/')
if not staticurl.endswith('/'):
staticurl += '/'
# some functions for the templater
def motd(**map):
yield self.config('web', 'motd')
# figure out which style to use
vars = {}
styles, (style, mapfile) = getstyle(req, self.config,
self.templatepath)
if style == styles[0]:
vars['style'] = style
sessionvars = webutil.sessionvars(vars, '?')
if not self.reponame:
self.reponame = (self.config('web', 'name', '')
or req.reponame
or req.apppath
or self.repo.root)
filters = {}
templatefilter = registrar.templatefilter(filters)
@templatefilter('websub', intype=bytes)
def websubfilter(text):
return templatefilters.websub(text, self.websubtable)
# create the templater
# TODO: export all keywords: defaults = templatekw.keywords.copy()
defaults = {
'url': req.apppath + '/',
'logourl': logourl,
'logoimg': logoimg,
'staticurl': staticurl,
'urlbase': req.advertisedbaseurl,
'repo': self.reponame,
'encoding': encoding.encoding,
'motd': motd,
'sessionvars': sessionvars,
'pathdef': makebreadcrumb(req.apppath),
'style': style,
'nonce': self.nonce,
}
tres = formatter.templateresources(self.repo.ui, self.repo)
tmpl = templater.templater.frommapfile(mapfile,
filters=filters,
defaults=defaults,
resources=tres)
return tmpl
def sendtemplate(self, name, **kwargs):
"""Helper function to send a response generated from a template."""
kwargs = pycompat.byteskwargs(kwargs)
self.res.setbodygen(self.tmpl.generate(name, kwargs))
return self.res.sendresponse()
class hgweb(object):
"""HTTP server for individual repositories.
Instances of this class serve HTTP responses for a particular
repository.
Instances are typically used as WSGI applications.
Some servers are multi-threaded. On these servers, there may
be multiple active threads inside __call__.
"""
def __init__(self, repo, name=None, baseui=None):
if isinstance(repo, bytes):
if baseui:
u = baseui.copy()
else:
u = uimod.ui.load()
r = hg.repository(u, repo)
else:
# we trust caller to give us a private copy
r = repo
r.ui.setconfig('ui', 'report_untrusted', 'off', 'hgweb')
r.baseui.setconfig('ui', 'report_untrusted', 'off', 'hgweb')
r.ui.setconfig('ui', 'nontty', 'true', 'hgweb')
r.baseui.setconfig('ui', 'nontty', 'true', 'hgweb')
# resolve file patterns relative to repo root
r.ui.setconfig('ui', 'forcecwd', r.root, 'hgweb')
r.baseui.setconfig('ui', 'forcecwd', r.root, 'hgweb')
# it's unlikely that we can replace signal handlers in WSGI server,
# and mod_wsgi issues a big warning. a plain hgweb process (with no
# threading) could replace signal handlers, but we don't bother
# conditionally enabling it.
r.ui.setconfig('ui', 'signal-safe-lock', 'false', 'hgweb')
r.baseui.setconfig('ui', 'signal-safe-lock', 'false', 'hgweb')
# displaying bundling progress bar while serving feel wrong and may
# break some wsgi implementation.
r.ui.setconfig('progress', 'disable', 'true', 'hgweb')
r.baseui.setconfig('progress', 'disable', 'true', 'hgweb')
self._repos = [hg.cachedlocalrepo(self._webifyrepo(r))]
self._lastrepo = self._repos[0]
hook.redirect(True)
self.reponame = name
def _webifyrepo(self, repo):
repo = getwebview(repo)
self.websubtable = webutil.getwebsubs(repo)
return repo
@contextlib.contextmanager
def _obtainrepo(self):
"""Obtain a repo unique to the caller.
Internally we maintain a stack of cachedlocalrepo instances
to be handed out. If one is available, we pop it and return it,
ensuring it is up to date in the process. If one is not available,
we clone the most recently used repo instance and return it.
It is currently possible for the stack to grow without bounds
if the server allows infinite threads. However, servers should
have a thread limit, thus establishing our limit.
"""
if self._repos:
cached = self._repos.pop()
r, created = cached.fetch()
else:
cached = self._lastrepo.copy()
r, created = cached.fetch()
if created:
r = self._webifyrepo(r)
self._lastrepo = cached
self.mtime = cached.mtime
try:
yield r
finally:
self._repos.append(cached)
def run(self):
"""Start a server from CGI environment.
Modern servers should be using WSGI and should avoid this
method, if possible.
"""
if not encoding.environ.get('GATEWAY_INTERFACE',
'').startswith("CGI/1."):
raise RuntimeError("This function is only intended to be "
"called while running as a CGI script.")
wsgicgi.launch(self)
def __call__(self, env, respond):
"""Run the WSGI application.
This may be called by multiple threads.
"""
req = requestmod.parserequestfromenv(env)
res = requestmod.wsgiresponse(req, respond)
return self.run_wsgi(req, res)
def run_wsgi(self, req, res):
"""Internal method to run the WSGI application.
This is typically only called by Mercurial. External consumers
should be using instances of this class as the WSGI application.
"""
with self._obtainrepo() as repo:
profile = repo.ui.configbool('profiling', 'enabled')
with profiling.profile(repo.ui, enabled=profile):
for r in self._runwsgi(req, res, repo):
yield r
def _runwsgi(self, req, res, repo):
rctx = requestcontext(self, repo, req, res)
# This state is global across all threads.
encoding.encoding = rctx.config('web', 'encoding')
rctx.repo.ui.environ = req.rawenv
if rctx.csp:
# hgwebdir may have added CSP header. Since we generate our own,
# replace it.
res.headers['Content-Security-Policy'] = rctx.csp
# /api/* is reserved for various API implementations. Dispatch
# accordingly. But URL paths can conflict with subrepos and virtual
# repos in hgwebdir. So until we have a workaround for this, only
# expose the URLs if the feature is enabled.
apienabled = rctx.repo.ui.configbool('experimental', 'web.apiserver')
if apienabled and req.dispatchparts and req.dispatchparts[0] == b'api':
wireprotoserver.handlewsgiapirequest(rctx, req, res,
self.check_perm)
return res.sendresponse()
handled = wireprotoserver.handlewsgirequest(
rctx, req, res, self.check_perm)
if handled:
return res.sendresponse()
# Old implementations of hgweb supported dispatching the request via
# the initial query string parameter instead of using PATH_INFO.
# If PATH_INFO is present (signaled by ``req.dispatchpath`` having
# a value), we use it. Otherwise fall back to the query string.
if req.dispatchpath is not None:
query = req.dispatchpath
else:
query = req.querystring.partition('&')[0].partition(';')[0]
# translate user-visible url structure to internal structure
args = query.split('/', 2)
if 'cmd' not in req.qsparams and args and args[0]:
cmd = args.pop(0)
style = cmd.rfind('-')
if style != -1:
req.qsparams['style'] = cmd[:style]
cmd = cmd[style + 1:]
# avoid accepting e.g. style parameter as command
if util.safehasattr(webcommands, cmd):
req.qsparams['cmd'] = cmd
if cmd == 'static':
req.qsparams['file'] = '/'.join(args)
else:
if args and args[0]:
node = args.pop(0).replace('%2F', '/')
req.qsparams['node'] = node
if args:
if 'file' in req.qsparams:
del req.qsparams['file']
for a in args:
req.qsparams.add('file', a)
ua = req.headers.get('User-Agent', '')
if cmd == 'rev' and 'mercurial' in ua:
req.qsparams['style'] = 'raw'
if cmd == 'archive':
fn = req.qsparams['node']
for type_, spec in webutil.archivespecs.iteritems():
ext = spec[2]
if fn.endswith(ext):
req.qsparams['node'] = fn[:-len(ext)]
req.qsparams['type'] = type_
else:
cmd = req.qsparams.get('cmd', '')
# process the web interface request
try:
rctx.tmpl = rctx.templater(req)
ctype = rctx.tmpl.render('mimetype',
{'encoding': encoding.encoding})
# check read permissions non-static content
if cmd != 'static':
self.check_perm(rctx, req, None)
if cmd == '':
req.qsparams['cmd'] = rctx.tmpl.render('default', {})
cmd = req.qsparams['cmd']
# Don't enable caching if using a CSP nonce because then it wouldn't
# be a nonce.
if rctx.configbool('web', 'cache') and not rctx.nonce:
tag = 'W/"%d"' % self.mtime
if req.headers.get('If-None-Match') == tag:
res.status = '304 Not Modified'
# Content-Type may be defined globally. It isn't valid on a
# 304, so discard it.
try:
del res.headers[b'Content-Type']
except KeyError:
pass
# Response body not allowed on 304.
res.setbodybytes('')
return res.sendresponse()
res.headers['ETag'] = tag
if cmd not in webcommands.__all__:
msg = 'no such method: %s' % cmd
raise ErrorResponse(HTTP_BAD_REQUEST, msg)
else:
# Set some globals appropriate for web handlers. Commands can
# override easily enough.
res.status = '200 Script output follows'
res.headers['Content-Type'] = ctype
return getattr(webcommands, cmd)(rctx)
except (error.LookupError, error.RepoLookupError) as err:
msg = pycompat.bytestr(err)
if (util.safehasattr(err, 'name') and
not isinstance(err, error.ManifestLookupError)):
msg = 'revision not found: %s' % err.name
res.status = '404 Not Found'
res.headers['Content-Type'] = ctype
return rctx.sendtemplate('error', error=msg)
except (error.RepoError, error.RevlogError) as e:
res.status = '500 Internal Server Error'
res.headers['Content-Type'] = ctype
return rctx.sendtemplate('error', error=pycompat.bytestr(e))
except ErrorResponse as e:
for k, v in e.headers:
res.headers[k] = v
res.status = statusmessage(e.code, pycompat.bytestr(e))
res.headers['Content-Type'] = ctype
return rctx.sendtemplate('error', error=pycompat.bytestr(e))
def check_perm(self, rctx, req, op):
for permhook in permhooks:
permhook(rctx, req, op)
def getwebview(repo):
"""The 'web.view' config controls changeset filter to hgweb. Possible
values are ``served``, ``visible`` and ``all``. Default is ``served``.
The ``served`` filter only shows changesets that can be pulled from the
hgweb instance. The``visible`` filter includes secret changesets but
still excludes "hidden" one.
See the repoview module for details.
The option has been around undocumented since Mercurial 2.5, but no
user ever asked about it. So we better keep it undocumented for now."""
# experimental config: web.view
viewconfig = repo.ui.config('web', 'view', untrusted=True)
if viewconfig == 'all':
return repo.unfiltered()
elif viewconfig in repoview.filtertable:
return repo.filtered(viewconfig)
else:
return repo.filtered('served')