exchange: move _computeellipsis() from narrow

This is also referenced as part of the narrow changegroup code and
therefore needs to move to core before we can integrate the narrow
changegroup code into core.

Differential Revision: https://phab.mercurial-scm.org/D4009

hgext/narrow/narrowbundle2.py

@@ -7,7 +7,6 b''
 
 from __future__ import absolute_import
 
-import collections
 import errno
 import struct
 
@@ -15,12 +14,10 b' from mercurial.i18n import _'
 from mercurial.node import (
     bin,
     nullid,
-    nullrev,
 )
 from mercurial import (
     bundle2,
     changegroup,
-    dagutil,
     error,
     exchange,
     extensions,
@@ -52,131 +49,6 b' def getrepocaps_narrow(orig, repo, **kwa'
     caps[NARROWCAP] = ['v0']
     return caps
 
-def _computeellipsis(repo, common, heads, known, match, depth=None):
-    """Compute the shape of a narrowed DAG.
-
-    Args:
-      repo: The repository we're transferring.
-      common: The roots of the DAG range we're transferring.
-              May be just [nullid], which means all ancestors of heads.
-      heads: The heads of the DAG range we're transferring.
-      match: The narrowmatcher that allows us to identify relevant changes.
-      depth: If not None, only consider nodes to be full nodes if they are at
-             most depth changesets away from one of heads.
-
-    Returns:
-      A tuple of (visitnodes, relevant_nodes, ellipsisroots) where:
-
-        visitnodes: The list of nodes (either full or ellipsis) which
-                    need to be sent to the client.
-        relevant_nodes: The set of changelog nodes which change a file inside
-                 the narrowspec. The client needs these as non-ellipsis nodes.
-        ellipsisroots: A dict of {rev: parents} that is used in
-                       narrowchangegroup to produce ellipsis nodes with the
-                       correct parents.
-    """
-    cl = repo.changelog
-    mfl = repo.manifestlog
-
-    cldag = dagutil.revlogdag(cl)
-    # dagutil does not like nullid/nullrev
-    commonrevs = cldag.internalizeall(common - set([nullid])) | set([nullrev])
-    headsrevs = cldag.internalizeall(heads)
-    if depth:
-        revdepth = {h: 0 for h in headsrevs}
-
-    ellipsisheads = collections.defaultdict(set)
-    ellipsisroots = collections.defaultdict(set)
-
-    def addroot(head, curchange):
-        """Add a root to an ellipsis head, splitting heads with 3 roots."""
-        ellipsisroots[head].add(curchange)
-        # Recursively split ellipsis heads with 3 roots by finding the
-        # roots' youngest common descendant which is an elided merge commit.
-        # That descendant takes 2 of the 3 roots as its own, and becomes a
-        # root of the head.
-        while len(ellipsisroots[head]) > 2:
-            child, roots = splithead(head)
-            splitroots(head, child, roots)
-            head = child  # Recurse in case we just added a 3rd root
-
-    def splitroots(head, child, roots):
-        ellipsisroots[head].difference_update(roots)
-        ellipsisroots[head].add(child)
-        ellipsisroots[child].update(roots)
-        ellipsisroots[child].discard(child)
-
-    def splithead(head):
-        r1, r2, r3 = sorted(ellipsisroots[head])
-        for nr1, nr2 in ((r2, r3), (r1, r3), (r1, r2)):
-            mid = repo.revs('sort(merge() & %d::%d & %d::%d, -rev)',
-                            nr1, head, nr2, head)
-            for j in mid:
-                if j == nr2:
-                    return nr2, (nr1, nr2)
-                if j not in ellipsisroots or len(ellipsisroots[j]) < 2:
-                    return j, (nr1, nr2)
-        raise error.Abort('Failed to split up ellipsis node! head: %d, '
-                          'roots: %d %d %d' % (head, r1, r2, r3))
-
-    missing = list(cl.findmissingrevs(common=commonrevs, heads=headsrevs))
-    visit = reversed(missing)
-    relevant_nodes = set()
-    visitnodes = [cl.node(m) for m in missing]
-    required = set(headsrevs) | known
-    for rev in visit:
-        clrev = cl.changelogrevision(rev)
-        ps = cldag.parents(rev)
-        if depth is not None:
-            curdepth = revdepth[rev]
-            for p in ps:
-                revdepth[p] = min(curdepth + 1, revdepth.get(p, depth + 1))
-        needed = False
-        shallow_enough = depth is None or revdepth[rev] <= depth
-        if shallow_enough:
-            curmf = mfl[clrev.manifest].read()
-            if ps:
-                # We choose to not trust the changed files list in
-                # changesets because it's not always correct. TODO: could
-                # we trust it for the non-merge case?
-                p1mf = mfl[cl.changelogrevision(ps[0]).manifest].read()
-                needed = bool(curmf.diff(p1mf, match))
-                if not needed and len(ps) > 1:
-                    # For merge changes, the list of changed files is not
-                    # helpful, since we need to emit the merge if a file
-                    # in the narrow spec has changed on either side of the
-                    # merge. As a result, we do a manifest diff to check.
-                    p2mf = mfl[cl.changelogrevision(ps[1]).manifest].read()
-                    needed = bool(curmf.diff(p2mf, match))
-            else:
-                # For a root node, we need to include the node if any
-                # files in the node match the narrowspec.
-                needed = any(curmf.walk(match))
-
-        if needed:
-            for head in ellipsisheads[rev]:
-                addroot(head, rev)
-            for p in ps:
-                required.add(p)
-            relevant_nodes.add(cl.node(rev))
-        else:
-            if not ps:
-                ps = [nullrev]
-            if rev in required:
-                for head in ellipsisheads[rev]:
-                    addroot(head, rev)
-                for p in ps:
-                    ellipsisheads[p].add(rev)
-            else:
-                for p in ps:
-                    ellipsisheads[p] |= ellipsisheads[rev]
-
-    # add common changesets as roots of their reachable ellipsis heads
-    for c in commonrevs:
-        for head in ellipsisheads[c]:
-            addroot(head, c)
-    return visitnodes, relevant_nodes, ellipsisroots
-
 def _packellipsischangegroup(repo, common, match, relevant_nodes,
                              ellipsisroots, visitnodes, depth, source, version):
     if version in ('01', '02'):
@@ -300,7 +172,7 b' def getbundlechangegrouppart_narrow(bund'
                 yield repo.changelog.node(r)
             yield _DONESIGNAL
         bundler.newpart(_CHANGESPECPART, data=genkills())
-        newvisit, newfull, newellipsis = _computeellipsis(
+        newvisit, newfull, newellipsis = exchange._computeellipsis(
             repo, set(), common, known, newmatch)
         if newvisit:
             cg = _packellipsischangegroup(
@@ -311,7 +183,7 b' def getbundlechangegrouppart_narrow(bund'
             if 'treemanifest' in repo.requirements:
                 part.addparam('treemanifest', '1')
 
-    visitnodes, relevant_nodes, ellipsisroots = _computeellipsis(
+    visitnodes, relevant_nodes, ellipsisroots = exchange._computeellipsis(
         repo, common, heads, set(), newmatch, depth=depth)
 
     repo.ui.debug('Found %d relevant revs\n' % len(relevant_nodes))

mercurial/exchange.py

@@ -15,6 +15,7 b' from .node import ('
     bin,
     hex,
     nullid,
+    nullrev,
 )
 from .thirdparty import (
     attr,
@@ -23,6 +24,7 b' from . import ('
     bookmarks as bookmod,
     bundle2,
     changegroup,
+    dagutil,
     discovery,
     error,
     lock as lockmod,
@@ -1875,6 +1877,131 b' def applynarrowacl(repo, kwargs):'
         new_args['excludepats'] = req_excludes
     return new_args
 
+def _computeellipsis(repo, common, heads, known, match, depth=None):
+    """Compute the shape of a narrowed DAG.
+
+    Args:
+      repo: The repository we're transferring.
+      common: The roots of the DAG range we're transferring.
+              May be just [nullid], which means all ancestors of heads.
+      heads: The heads of the DAG range we're transferring.
+      match: The narrowmatcher that allows us to identify relevant changes.
+      depth: If not None, only consider nodes to be full nodes if they are at
+             most depth changesets away from one of heads.
+
+    Returns:
+      A tuple of (visitnodes, relevant_nodes, ellipsisroots) where:
+
+        visitnodes: The list of nodes (either full or ellipsis) which
+                    need to be sent to the client.
+        relevant_nodes: The set of changelog nodes which change a file inside
+                 the narrowspec. The client needs these as non-ellipsis nodes.
+        ellipsisroots: A dict of {rev: parents} that is used in
+                       narrowchangegroup to produce ellipsis nodes with the
+                       correct parents.
+    """
+    cl = repo.changelog
+    mfl = repo.manifestlog
+
+    cldag = dagutil.revlogdag(cl)
+    # dagutil does not like nullid/nullrev
+    commonrevs = cldag.internalizeall(common - set([nullid])) | set([nullrev])
+    headsrevs = cldag.internalizeall(heads)
+    if depth:
+        revdepth = {h: 0 for h in headsrevs}
+
+    ellipsisheads = collections.defaultdict(set)
+    ellipsisroots = collections.defaultdict(set)
+
+    def addroot(head, curchange):
+        """Add a root to an ellipsis head, splitting heads with 3 roots."""
+        ellipsisroots[head].add(curchange)
+        # Recursively split ellipsis heads with 3 roots by finding the
+        # roots' youngest common descendant which is an elided merge commit.
+        # That descendant takes 2 of the 3 roots as its own, and becomes a
+        # root of the head.
+        while len(ellipsisroots[head]) > 2:
+            child, roots = splithead(head)
+            splitroots(head, child, roots)
+            head = child  # Recurse in case we just added a 3rd root
+
+    def splitroots(head, child, roots):
+        ellipsisroots[head].difference_update(roots)
+        ellipsisroots[head].add(child)
+        ellipsisroots[child].update(roots)
+        ellipsisroots[child].discard(child)
+
+    def splithead(head):
+        r1, r2, r3 = sorted(ellipsisroots[head])
+        for nr1, nr2 in ((r2, r3), (r1, r3), (r1, r2)):
+            mid = repo.revs('sort(merge() & %d::%d & %d::%d, -rev)',
+                            nr1, head, nr2, head)
+            for j in mid:
+                if j == nr2:
+                    return nr2, (nr1, nr2)
+                if j not in ellipsisroots or len(ellipsisroots[j]) < 2:
+                    return j, (nr1, nr2)
+        raise error.Abort(_('Failed to split up ellipsis node! head: %d, '
+                            'roots: %d %d %d') % (head, r1, r2, r3))
+
+    missing = list(cl.findmissingrevs(common=commonrevs, heads=headsrevs))
+    visit = reversed(missing)
+    relevant_nodes = set()
+    visitnodes = [cl.node(m) for m in missing]
+    required = set(headsrevs) | known
+    for rev in visit:
+        clrev = cl.changelogrevision(rev)
+        ps = cldag.parents(rev)
+        if depth is not None:
+            curdepth = revdepth[rev]
+            for p in ps:
+                revdepth[p] = min(curdepth + 1, revdepth.get(p, depth + 1))
+        needed = False
+        shallow_enough = depth is None or revdepth[rev] <= depth
+        if shallow_enough:
+            curmf = mfl[clrev.manifest].read()
+            if ps:
+                # We choose to not trust the changed files list in
+                # changesets because it's not always correct. TODO: could
+                # we trust it for the non-merge case?
+                p1mf = mfl[cl.changelogrevision(ps[0]).manifest].read()
+                needed = bool(curmf.diff(p1mf, match))
+                if not needed and len(ps) > 1:
+                    # For merge changes, the list of changed files is not
+                    # helpful, since we need to emit the merge if a file
+                    # in the narrow spec has changed on either side of the
+                    # merge. As a result, we do a manifest diff to check.
+                    p2mf = mfl[cl.changelogrevision(ps[1]).manifest].read()
+                    needed = bool(curmf.diff(p2mf, match))
+            else:
+                # For a root node, we need to include the node if any
+                # files in the node match the narrowspec.
+                needed = any(curmf.walk(match))
+
+        if needed:
+            for head in ellipsisheads[rev]:
+                addroot(head, rev)
+            for p in ps:
+                required.add(p)
+            relevant_nodes.add(cl.node(rev))
+        else:
+            if not ps:
+                ps = [nullrev]
+            if rev in required:
+                for head in ellipsisheads[rev]:
+                    addroot(head, rev)
+                for p in ps:
+                    ellipsisheads[p].add(rev)
+            else:
+                for p in ps:
+                    ellipsisheads[p] |= ellipsisheads[rev]
+
+    # add common changesets as roots of their reachable ellipsis heads
+    for c in commonrevs:
+        for head in ellipsisheads[c]:
+            addroot(head, c)
+    return visitnodes, relevant_nodes, ellipsisroots
+
 def caps20to10(repo, role):
     """return a set with appropriate options to use bundle20 during getbundle"""
     caps = {'HG20'}