repoview: add visibilityexception argument to filterrevs() and related fns

repoview: add visibilityexception argument to filterrevs() and related fns

After this patch, filterrevs() can take an optional argument
visibilityexceptions which is a set of revs which should be exception to
being hidden. The visibilityexceptions will be passed to the function computing
hidden revisions for that filtername and are considered there while calculating
the set of hidden revs.

Differential Revision: https://phab.mercurial-scm.org/D1747

--- a/mercurial/repoview.py	Fri Dec 22 17:57:11 2017 +0530
+++ b/mercurial/repoview.py	Fri Dec 22 22:19:42 2017 +0530
@@ -65,7 +65,7 @@
                 hidden.remove(p)
                 stack.append(p)
 
-def computehidden(repo):
+def computehidden(repo, visibilityexceptions=None):
     """compute the set of hidden revision to filter
 
     During most operation hidden should be filtered."""
@@ -74,6 +74,8 @@
     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)
@@ -82,7 +84,7 @@
         _revealancestors(pfunc, hidden, visible)
     return frozenset(hidden)
 
-def computeunserved(repo):
+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."""
@@ -100,7 +102,7 @@
     else:
         return hiddens
 
-def computemutable(repo):
+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:]):
@@ -109,7 +111,7 @@
         return frozenset(r for r in maymutable if getphase(repo, r))
     return frozenset()
 
-def computeimpactable(repo):
+def computeimpactable(repo, visibilityexceptions=None):
     """Everything impactable by mutable revision
 
     The immutable filter still have some chance to get invalidated. This will
@@ -145,10 +147,16 @@
                'immutable':  computemutable,
                'base':  computeimpactable}
 
-def filterrevs(repo, filtername):
-    """returns set of filtered revision for this filter name"""
+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]
 
@@ -210,7 +218,7 @@
         unfilen = len(unfiindex) - 1
         unfinode = unfiindex[unfilen - 1][7]
 
-        revs = filterrevs(unfi, self.filtername)
+        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