wireprotov2: change command response protocol to include a leading map
The error handling mechanism for the new wire protocol isn't very
well-defined. This commit takes us a step in the right direction
by introducing a leading CBOR map for command responses. This map
will contain an overall result of the command.
Currently, the map indicates whether the command was overall
successful or if an error occurred. And if an error occurred, that
error is present in the map.
There is still a dedicated error frame. My intent is to use that
for protocol-level errors and for errors that are encountered after
the initial response frame has been sent. This will be clarified in a
later commit.
Differential Revision: https://phab.mercurial-scm.org/D3385
# repoview.py - Filtered view of a localrepo object
#
# Copyright 2012 Pierre-Yves David <pierre-yves.david@ens-lyon.org>
# Logilab SA <contact@logilab.fr>
#
# 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 copy
import weakref
from .node import nullrev
from . import (
obsolete,
phases,
pycompat,
tags as tagsmod,
)
def hideablerevs(repo):
"""Revision candidates to be hidden
This is a standalone function to allow extensions to wrap it.
Because we use the set of immutable changesets as a fallback subset in
branchmap (see mercurial.branchmap.subsettable), you cannot set "public"
changesets as "hideable". Doing so would break multiple code assertions and
lead to crashes."""
return obsolete.getrevs(repo, 'obsolete')
def pinnedrevs(repo):
"""revisions blocking hidden changesets from being filtered
"""
cl = repo.changelog
pinned = set()
pinned.update([par.rev() for par in repo[None].parents()])
pinned.update([cl.rev(bm) for bm in repo._bookmarks.values()])
tags = {}
tagsmod.readlocaltags(repo.ui, repo, tags, {})
if tags:
rev, nodemap = cl.rev, cl.nodemap
pinned.update(rev(t[0]) for t in tags.values() if t[0] in nodemap)
return pinned
def _revealancestors(pfunc, hidden, revs):
"""reveals contiguous chains of hidden ancestors of 'revs' by removing them
from 'hidden'
- pfunc(r): a funtion returning parent of 'r',
- hidden: the (preliminary) hidden revisions, to be updated
- revs: iterable of revnum,
(Ancestors are revealed exclusively, i.e. the elements in 'revs' are
*not* revealed)
"""
stack = list(revs)
while stack:
for p in pfunc(stack.pop()):
if p != nullrev and p in hidden:
hidden.remove(p)
stack.append(p)
def computehidden(repo, visibilityexceptions=None):
"""compute the set of hidden revision to filter
During most operation hidden should be filtered."""
assert not repo.changelog.filteredrevs
hidden = hideablerevs(repo)
if hidden:
hidden = set(hidden - pinnedrevs(repo))
if visibilityexceptions:
hidden -= visibilityexceptions
pfunc = repo.changelog.parentrevs
mutablephases = (phases.draft, phases.secret)
mutable = repo._phasecache.getrevset(repo, mutablephases)
visible = mutable - hidden
_revealancestors(pfunc, hidden, visible)
return frozenset(hidden)
def computeunserved(repo, visibilityexceptions=None):
"""compute the set of revision that should be filtered when used a server
Secret and hidden changeset should not pretend to be here."""
assert not repo.changelog.filteredrevs
# fast path in simple case to avoid impact of non optimised code
hiddens = filterrevs(repo, 'visible')
if phases.hassecret(repo):
cl = repo.changelog
secret = phases.secret
getphase = repo._phasecache.phase
first = min(cl.rev(n) for n in repo._phasecache.phaseroots[secret])
revs = cl.revs(start=first)
secrets = set(r for r in revs if getphase(repo, r) >= secret)
return frozenset(hiddens | secrets)
else:
return hiddens
def computemutable(repo, visibilityexceptions=None):
assert not repo.changelog.filteredrevs
# fast check to avoid revset call on huge repo
if any(repo._phasecache.phaseroots[1:]):
getphase = repo._phasecache.phase
maymutable = filterrevs(repo, 'base')
return frozenset(r for r in maymutable if getphase(repo, r))
return frozenset()
def computeimpactable(repo, visibilityexceptions=None):
"""Everything impactable by mutable revision
The immutable filter still have some chance to get invalidated. This will
happen when:
- you garbage collect hidden changeset,
- public phase is moved backward,
- something is changed in the filtering (this could be fixed)
This filter out any mutable changeset and any public changeset that may be
impacted by something happening to a mutable revision.
This is achieved by filtered everything with a revision number egal or
higher than the first mutable changeset is filtered."""
assert not repo.changelog.filteredrevs
cl = repo.changelog
firstmutable = len(cl)
for roots in repo._phasecache.phaseroots[1:]:
if roots:
firstmutable = min(firstmutable, min(cl.rev(r) for r in roots))
# protect from nullrev root
firstmutable = max(0, firstmutable)
return frozenset(xrange(firstmutable, len(cl)))
# function to compute filtered set
#
# When adding a new filter you MUST update the table at:
# mercurial.branchmap.subsettable
# Otherwise your filter will have to recompute all its branches cache
# from scratch (very slow).
filtertable = {'visible': computehidden,
'visible-hidden': computehidden,
'served': computeunserved,
'immutable': computemutable,
'base': computeimpactable}
def filterrevs(repo, filtername, visibilityexceptions=None):
"""returns set of filtered revision for this filter name
visibilityexceptions is a set of revs which must are exceptions for
hidden-state and must be visible. They are dynamic and hence we should not
cache it's result"""
if filtername not in repo.filteredrevcache:
func = filtertable[filtername]
if visibilityexceptions:
return func(repo.unfiltered, visibilityexceptions)
repo.filteredrevcache[filtername] = func(repo.unfiltered())
return repo.filteredrevcache[filtername]
class repoview(object):
"""Provide a read/write view of a repo through a filtered changelog
This object is used to access a filtered version of a repository without
altering the original repository object itself. We can not alter the
original object for two main reasons:
- It prevents the use of a repo with multiple filters at the same time. In
particular when multiple threads are involved.
- It makes scope of the filtering harder to control.
This object behaves very closely to the original repository. All attribute
operations are done on the original repository:
- An access to `repoview.someattr` actually returns `repo.someattr`,
- A write to `repoview.someattr` actually sets value of `repo.someattr`,
- A deletion of `repoview.someattr` actually drops `someattr`
from `repo.__dict__`.
The only exception is the `changelog` property. It is overridden to return
a (surface) copy of `repo.changelog` with some revisions filtered. The
`filtername` attribute of the view control the revisions that need to be
filtered. (the fact the changelog is copied is an implementation detail).
Unlike attributes, this object intercepts all method calls. This means that
all methods are run on the `repoview` object with the filtered `changelog`
property. For this purpose the simple `repoview` class must be mixed with
the actual class of the repository. This ensures that the resulting
`repoview` object have the very same methods than the repo object. This
leads to the property below.
repoview.method() --> repo.__class__.method(repoview)
The inheritance has to be done dynamically because `repo` can be of any
subclasses of `localrepo`. Eg: `bundlerepo` or `statichttprepo`.
"""
def __init__(self, repo, filtername, visibilityexceptions=None):
object.__setattr__(self, r'_unfilteredrepo', repo)
object.__setattr__(self, r'filtername', filtername)
object.__setattr__(self, r'_clcachekey', None)
object.__setattr__(self, r'_clcache', None)
# revs which are exceptions and must not be hidden
object.__setattr__(self, r'_visibilityexceptions',
visibilityexceptions)
# not a propertycache on purpose we shall implement a proper cache later
@property
def changelog(self):
"""return a filtered version of the changeset
this changelog must not be used for writing"""
# some cache may be implemented later
unfi = self._unfilteredrepo
unfichangelog = unfi.changelog
# bypass call to changelog.method
unfiindex = unfichangelog.index
unfilen = len(unfiindex) - 1
unfinode = unfiindex[unfilen - 1][7]
revs = filterrevs(unfi, self.filtername, self._visibilityexceptions)
cl = self._clcache
newkey = (unfilen, unfinode, hash(revs), unfichangelog._delayed)
# if cl.index is not unfiindex, unfi.changelog would be
# recreated, and our clcache refers to garbage object
if (cl is not None and
(cl.index is not unfiindex or newkey != self._clcachekey)):
cl = None
# could have been made None by the previous if
if cl is None:
cl = copy.copy(unfichangelog)
cl.filteredrevs = revs
object.__setattr__(self, r'_clcache', cl)
object.__setattr__(self, r'_clcachekey', newkey)
return cl
def unfiltered(self):
"""Return an unfiltered version of a repo"""
return self._unfilteredrepo
def filtered(self, name, visibilityexceptions=None):
"""Return a filtered version of a repository"""
if name == self.filtername and not visibilityexceptions:
return self
return self.unfiltered().filtered(name, visibilityexceptions)
def __repr__(self):
return r'<%s:%s %r>' % (self.__class__.__name__,
pycompat.sysstr(self.filtername),
self.unfiltered())
# everything access are forwarded to the proxied repo
def __getattr__(self, attr):
return getattr(self._unfilteredrepo, attr)
def __setattr__(self, attr, value):
return setattr(self._unfilteredrepo, attr, value)
def __delattr__(self, attr):
return delattr(self._unfilteredrepo, attr)
# Python <3.4 easily leaks types via __mro__. See
# https://bugs.python.org/issue17950. We cache dynamically created types
# so they won't be leaked on every invocation of repo.filtered().
_filteredrepotypes = weakref.WeakKeyDictionary()
def newtype(base):
"""Create a new type with the repoview mixin and the given base class"""
if base not in _filteredrepotypes:
class filteredrepo(repoview, base):
pass
_filteredrepotypes[base] = filteredrepo
return _filteredrepotypes[base]