snapshot: add refining logic at the findeltainfo level
authorBoris Feld <boris.feld@octobus.net>
Fri, 07 Sep 2018 11:17:33 -0400
changeset 39515 04b75f3a3f2a
parent 39514 5b308a4e6d03
child 39516 51cec7fb672e
snapshot: add refining logic at the findeltainfo level Once we found a delta, we want to have the candidates logic challenge it, searching for a better candidate. The logic at the lower level is still missing. We'll introduce it later. Adding small changes in individual commits make it simpler to explain the code change. This is another small step toward turning `_refinegroups` into a co-routine.
mercurial/revlogutils/deltas.py
--- a/mercurial/revlogutils/deltas.py	Fri Sep 07 11:17:32 2018 -0400
+++ b/mercurial/revlogutils/deltas.py	Fri Sep 07 11:17:33 2018 -0400
@@ -582,6 +582,7 @@
 
     deltalength = revlog.length
     deltaparent = revlog.deltaparent
+    good = None
 
     deltas_limit = textlen * LIMIT_DELTA2TEXT
 
@@ -612,7 +613,9 @@
             # XXX: in the sparse revlog case, group can become large,
             #      impacting performances. Some bounding or slicing mecanism
             #      would help to reduce this impact.
-            yield tuple(group)
+            good = yield tuple(group)
+        if good is not None:
+            break
     yield None
 
 def _findsnapshots(revlog, cache, start_rev):
@@ -847,14 +850,20 @@
         candidaterevs = next(groups)
         while candidaterevs is not None:
             nominateddeltas = []
+            if deltainfo is not None:
+                # if we already found a good delta,
+                # challenge it against refined candidates
+                nominateddeltas.append(deltainfo)
             for candidaterev in candidaterevs:
                 candidatedelta = self._builddeltainfo(revinfo, candidaterev, fh)
                 if isgooddeltainfo(self.revlog, candidatedelta, revinfo):
                     nominateddeltas.append(candidatedelta)
             if nominateddeltas:
                 deltainfo = min(nominateddeltas, key=lambda x: x.deltalen)
-                break
-            candidaterevs = next(groups)
+            if deltainfo is not None:
+                candidaterevs = groups.send(deltainfo.base)
+            else:
+                candidaterevs = next(groups)
 
         if deltainfo is None:
             deltainfo = self._fullsnapshotinfo(fh, revinfo)