hidden: change _domainancestors() to _revealancestors()

This change makes the function actually reveal the ancestors by
removing them from the hidden set. This prepares for further
simplification.

Note that the function will now only reveal contiguous chains of
hidden revisions, but that's fine because we always pass it an
immediate child of any revision that should be revealed (or the
revision itself).

This doesn't seem to have much impact on "perfvolatilesets".

Before:
! obsolete
! wall 0.004672 comb 0.010000 user 0.010000 sys 0.000000 (best of 590)
! visible
! wall 0.008936 comb 0.010000 user 0.010000 sys 0.000000 (best of 322)

After:
! obsolete
! wall 0.004903 comb 0.000000 user 0.000000 sys 0.000000 (best of 535)
! visible
! wall 0.008913 comb 0.010000 user 0.010000 sys 0.000000 (best of 300)

mercurial/repoview.py

@@ -1,289 +1,293 b''
 # repoview.py - Filtered view of a localrepo object
 #
 # Copyright 2012 Pierre-Yves David <[e-mail]>
 #                Logilab SA        <[e-mail]>
 #
 # 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
 
 from .node import nullrev
 from . import (
     obsolete,
     phases,
     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 _consistencyblocker(pfunc, hideable, domain):
     """return non-hideable changeset blocking hideable one
 
     For consistency, we cannot actually hide a changeset if one of it children
     are visible, this function find such children.
     """
     others = domain - hideable
     blockers = set()
     for r in others:
         for p in pfunc(r):
             if p != nullrev and p in hideable:
                 blockers.add(r)
                 break
     return blockers
 
-def _domainancestors(pfunc, revs, domain):
-    """return ancestors of 'revs' within 'domain'
+def _revealancestors(pfunc, hidden, revs, domain):
+    """reveals contiguous chains of hidden ancestors of 'revs' within 'domain'
+    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,
     - domain: consistent set of revnum.
 
     The domain must be consistent: no connected subset are the ancestors of
     another connected subset. In other words, if the parents of a revision are
     not in the domains, no other ancestors of that revision. For example, with
     the following graph:
 
         F
         |
         E
         | D
         | |
         | C
         |/
         B
         |
         A
 
     If C, D, E and F are in the domain but B is not, A cannot be ((A) is an
     ancestors disconnected subset disconnected of (C+D)).
 
-    (Ancestors are returned inclusively)
+    (Ancestors are revealed inclusively, i.e. the elements in 'revs' are
+    also revealed)
     """
     stack = list(revs)
-    ancestors = set(stack)
+    hidden -= set(stack)
     while stack:
         for p in pfunc(stack.pop()):
-            if p != nullrev and p in domain and p not in ancestors:
-                ancestors.add(p)
+            if p != nullrev and p in domain and p in hidden:
+                hidden.remove(p)
                 stack.append(p)
-    return ancestors
 
 def computehidden(repo):
     """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:
         pfunc = repo.changelog.parentrevs
         mutablephases = (phases.draft, phases.secret)
         mutable = repo._phasecache.getrevset(repo, mutablephases)
 
         blockers = _consistencyblocker(pfunc, hidden, mutable)
 
         # check if we have wd parents, bookmarks or tags pointing to hidden
         # changesets and remove those.
         blockers |= (hidden & pinnedrevs(repo))
         if blockers:
-            hidden = hidden - _domainancestors(pfunc, blockers, mutable)
+            # don't modify possibly cached result of hideablerevs()
+            hidden = hidden.copy()
+            _revealancestors(pfunc, hidden, blockers, mutable)
     return frozenset(hidden)
 
 def computeunserved(repo):
     """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):
     """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 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):
     """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,
                'served': computeunserved,
                'immutable':  computemutable,
                'base':  computeimpactable}
 
 def filterrevs(repo, filtername):
     """returns set of filtered revision for this filter name"""
     if filtername not in repo.filteredrevcache:
         func = filtertable[filtername]
         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):
         object.__setattr__(self, r'_unfilteredrepo', repo)
         object.__setattr__(self, r'filtername', filtername)
         object.__setattr__(self, r'_clcachekey', None)
         object.__setattr__(self, r'_clcache', None)
 
     # 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)
         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):
         """Return a filtered version of a repository"""
         if name == self.filtername:
             return self
         return self.unfiltered().filtered(name)
 
     # 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)
 
     # The `requirements` attribute is initialized during __init__. But
     # __getattr__ won't be called as it also exists on the class. We need
     # explicit forwarding to main repo here
     @property
     def requirements(self):
         return self._unfilteredrepo.requirements