Mercurial > hg
view mercurial/repoview.py @ 39604:335ae4d0a552
bundlerepo: dynamically create repository type from base repository
Previously, bundlerepository inherited from localrepo.localrepository.
You simply instantiated a bundlerepository and its __init__ called
localrepo.localrepository.__init__. Things were simple.
Unfortunately, this strategy is limiting because it assumes that
the base repository is a localrepository instance. And it assumes
various properties of localrepository, such as the arguments its
__init__ takes. And it prevents us from changing behavior of
localrepository.__init__ without also having to change derived classes.
Previous and ongoing work to abstract storage revealed these
limitations.
This commit changes the initialization strategy of bundle repositories
to dynamically create a type to represent the repository. Instead of
a static type, we instantiate a new local repo instance via
localrepo.instance(). We then combine its __class__ with
bundlerepository to produce a new type. This ensures that no matter
how localrepo.instance() decides to create a repository object, we
can derive a bundle repo object from it. i.e. localrepo.instance()
could return a type that isn't a localrepository and it would "just
work."
Well, it would "just work" if bundlerepository's custom implementations
only accessed attributes in the documented repository interface. I'm
pretty sure it violates the interface contract in a handful of
places. But we can worry about that another day. This change gets us
closer to doing more clever things around instantiating repository
instances without having to worry about teaching bundlerepository about
them.
.. api::
``bundlerepo.bundlerepository`` is no longer usable on its own.
The class is combined with the class of the base repository it is
associated with at run-time.
New bundlerepository instances can be obtained by calling
``bundlerepo.instance()`` or ``bundlerepo.makebundlerepository()``.
Differential Revision: https://phab.mercurial-scm.org/D4555
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 11 Sep 2018 19:50:07 -0700 |
parents | 06c976acc581 |
children | bc15e37ecc16 |
line wrap: on
line source
# 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.""" obsoletes = obsolete.getrevs(repo, 'obsolete') internals = repo._phasecache.getrevset(repo, phases.localhiddenphases) internals = frozenset(internals) return obsoletes | internals 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 mutable = repo._phasecache.getrevset(repo, phases.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): secrets = repo._phasecache.getrevset(repo, phases.remotehiddenphases) return frozenset(hiddens | frozenset(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(pycompat.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) 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]