mercurial/changegroup.py
changeset 39055 ef3d3a2f9aa5
parent 39054 39b8277e2115
child 39056 e793e11e1462
--- a/mercurial/changegroup.py	Wed Aug 08 16:01:26 2018 -0700
+++ b/mercurial/changegroup.py	Wed Aug 08 20:17:48 2018 -0700
@@ -587,11 +587,37 @@
     key = lambda n: cl.rev(lookup(n))
     return [store.rev(n) for n in sorted(nodes, key=key)]
 
-def _revisiondeltanormal(store, rev, prev, linknode, deltaparentfn):
+def _revisiondeltanormal(store, rev, prev, linknode, forcedeltaparentprev):
     """Construct a revision delta for non-ellipses changegroup generation."""
     node = store.node(rev)
     p1, p2 = store.parentrevs(rev)
-    base = deltaparentfn(store, rev, p1, p2, prev)
+
+    if forcedeltaparentprev:
+        base = prev
+    else:
+        dp = store.deltaparent(rev)
+
+        if dp == nullrev and store.storedeltachains:
+            # Avoid sending full revisions when delta parent is null. Pick prev
+            # in that case. It's tempting to pick p1 in this case, as p1 will
+            # be smaller in the common case. However, computing a delta against
+            # p1 may require resolving the raw text of p1, which could be
+            # expensive. The revlog caches should have prev cached, meaning
+            # less CPU for changegroup generation. There is likely room to add
+            # a flag and/or config option to control this behavior.
+            base = prev
+        elif dp == nullrev:
+            # revlog is configured to use full snapshot for a reason,
+            # stick to full snapshot.
+            base = nullrev
+        elif dp not in (p1, p2, prev):
+            # Pick prev when we can't be sure remote has the base revision.
+            base = prev
+        else:
+            base = dp
+
+        if base != nullrev and not store.candelta(base, rev):
+            base = nullrev
 
     revision = None
     delta = None
@@ -719,7 +745,7 @@
         delta=None,
     )
 
-def deltagroup(repo, revs, store, ischangelog, lookup, deltaparentfn,
+def deltagroup(repo, revs, store, ischangelog, lookup, forcedeltaparentprev,
                units=None,
                ellipses=False, clrevtolocalrev=None, fullclnodes=None,
                precomputedellipsis=None):
@@ -761,7 +787,7 @@
             # corresponds to was a full changeset.
             if linknode in fullclnodes:
                 delta = _revisiondeltanormal(store, curr, prev, linknode,
-                                             deltaparentfn)
+                                             forcedeltaparentprev)
             elif linkrev not in precomputedellipsis:
                 delta = None
             else:
@@ -771,7 +797,7 @@
                     precomputedellipsis)
         else:
             delta = _revisiondeltanormal(store, curr, prev, linknode,
-                                         deltaparentfn)
+                                         forcedeltaparentprev)
 
         if delta:
             yield delta
@@ -781,7 +807,8 @@
 
 class cgpacker(object):
     def __init__(self, repo, filematcher, version, allowreorder,
-                 deltaparentfn, builddeltaheader, manifestsend,
+                 builddeltaheader, manifestsend,
+                 forcedeltaparentprev=False,
                  bundlecaps=None, ellipses=False,
                  shallow=False, ellipsisroots=None, fullnodes=None):
         """Given a source repo, construct a bundler.
@@ -793,8 +820,9 @@
         This value is used when ``bundle.reorder`` is ``auto`` or isn't
         set.
 
-        deltaparentfn is a callable that resolves the delta parent for
-        a specific revision.
+        forcedeltaparentprev indicates whether delta parents must be against
+        the previous revision in a delta group. This should only be used for
+        compatibility with changegroup version 1.
 
         builddeltaheader is a callable that constructs the header for a group
         delta.
@@ -820,7 +848,7 @@
         self._filematcher = filematcher
 
         self.version = version
-        self._deltaparentfn = deltaparentfn
+        self._forcedeltaparentprev = forcedeltaparentprev
         self._builddeltaheader = builddeltaheader
         self._manifestsend = manifestsend
         self._ellipses = ellipses
@@ -1025,7 +1053,7 @@
 
         gen = deltagroup(
             self._repo, revs, cl, True, lookupcl,
-            self._deltaparentfn,
+            self._forcedeltaparentprev,
             ellipses=self._ellipses,
             units=_('changesets'),
             clrevtolocalrev={},
@@ -1114,7 +1142,7 @@
 
             deltas = deltagroup(
                 self._repo, revs, store, False, lookupfn,
-                self._deltaparentfn,
+                self._forcedeltaparentprev,
                 ellipses=self._ellipses,
                 units=_('manifests'),
                 clrevtolocalrev=clrevtolocalrev,
@@ -1206,7 +1234,7 @@
 
                 deltas = deltagroup(
                     self._repo, revs, filerevlog, False, lookupfilelog,
-                    self._deltaparentfn,
+                    self._forcedeltaparentprev,
                     ellipses=self._ellipses,
                     clrevtolocalrev=clrevtolocalrev,
                     fullclnodes=self._fullclnodes,
@@ -1216,65 +1244,16 @@
 
         progress.complete()
 
-def _deltaparentprev(store, rev, p1, p2, prev):
-    """Resolve a delta parent to the previous revision.
-
-    Used for version 1 changegroups, which don't support generaldelta.
-    """
-    return prev
-
-def _deltaparentgeneraldelta(store, rev, p1, p2, prev):
-    """Resolve a delta parent when general deltas are supported."""
-    dp = store.deltaparent(rev)
-    if dp == nullrev and store.storedeltachains:
-        # Avoid sending full revisions when delta parent is null. Pick prev
-        # in that case. It's tempting to pick p1 in this case, as p1 will
-        # be smaller in the common case. However, computing a delta against
-        # p1 may require resolving the raw text of p1, which could be
-        # expensive. The revlog caches should have prev cached, meaning
-        # less CPU for changegroup generation. There is likely room to add
-        # a flag and/or config option to control this behavior.
-        base = prev
-    elif dp == nullrev:
-        # revlog is configured to use full snapshot for a reason,
-        # stick to full snapshot.
-        base = nullrev
-    elif dp not in (p1, p2, prev):
-        # Pick prev when we can't be sure remote has the base revision.
-        return prev
-    else:
-        base = dp
-
-    if base != nullrev and not store.candelta(base, rev):
-        base = nullrev
-
-    return base
-
-def _deltaparentellipses(store, rev, p1, p2, prev):
-    """Resolve a delta parent when in ellipses mode."""
-    # TODO: send better deltas when in narrow mode.
-    #
-    # changegroup.group() loops over revisions to send,
-    # including revisions we'll skip. What this means is that
-    # `prev` will be a potentially useless delta base for all
-    # ellipsis nodes, as the client likely won't have it. In
-    # the future we should do bookkeeping about which nodes
-    # have been sent to the client, and try to be
-    # significantly smarter about delta bases. This is
-    # slightly tricky because this same code has to work for
-    # all revlogs, and we don't have the linkrev/linknode here.
-    return p1
-
 def _makecg1packer(repo, filematcher, bundlecaps, ellipses=False,
                    shallow=False, ellipsisroots=None, fullnodes=None):
     builddeltaheader = lambda d: _CHANGEGROUPV1_DELTA_HEADER.pack(
         d.node, d.p1node, d.p2node, d.linknode)
 
     return cgpacker(repo, filematcher, b'01',
-                    deltaparentfn=_deltaparentprev,
                     allowreorder=None,
                     builddeltaheader=builddeltaheader,
                     manifestsend=b'',
+                    forcedeltaparentprev=True,
                     bundlecaps=bundlecaps,
                     ellipses=ellipses,
                     shallow=shallow,
@@ -1290,7 +1269,6 @@
     # generally doesn't help, so we disable it by default (treating
     # bundle.reorder=auto just like bundle.reorder=False).
     return cgpacker(repo, filematcher, b'02',
-                    deltaparentfn=_deltaparentgeneraldelta,
                     allowreorder=False,
                     builddeltaheader=builddeltaheader,
                     manifestsend=b'',
@@ -1305,11 +1283,7 @@
     builddeltaheader = lambda d: _CHANGEGROUPV3_DELTA_HEADER.pack(
         d.node, d.p1node, d.p2node, d.basenode, d.linknode, d.flags)
 
-    deltaparentfn = (_deltaparentellipses if ellipses
-                     else _deltaparentgeneraldelta)
-
     return cgpacker(repo, filematcher, b'03',
-                    deltaparentfn=deltaparentfn,
                     allowreorder=False,
                     builddeltaheader=builddeltaheader,
                     manifestsend=closechunk(),