D3573: hgweb: extract code for emitting multiple changelist records

[indygreg (Gregory Szorc)]

indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  changelistentry() exists so extensions can easily monkeypatch the
  function to add additional metadata.
  
  In at least one case at Mozilla, we have an extension doing this
  where performance would greatly benefit if we were able to "batch
  fetch" metadata for all revisions that will eventually have their
  data set.
  
  By extracting the logic for "obtain records for N revisions" into
  a standalone function, we make it possible for a monkeypatched
  function to more efficiently bulk fetch data for N revisions.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3573

AFFECTED FILES
  mercurial/hgweb/webcommands.py
  mercurial/hgweb/webutil.py

CHANGE DETAILS

diff --git a/mercurial/hgweb/webutil.py b/mercurial/hgweb/webutil.py
--- a/mercurial/hgweb/webutil.py
+++ b/mercurial/hgweb/webutil.py
@@ -457,6 +457,22 @@
     )
     return entry
 
+def changelistentries(web, revs, maxcount, parityfn):
+    """Emit up to N records for an iterable of revisions."""
+    repo = web.repo
+
+    count = 0
+    for rev in revs:
+        if count >= maxcount:
+            break
+
+        count += 1
+
+        entry = changelistentry(web, repo[rev])
+        entry['parity'] = next(parityfn)
+
+        yield entry
+
 def symrevorshortnode(req, ctx):
     if 'node' in req.qsparams:
         return templatefilters.revescape(req.qsparams['node'])
diff --git a/mercurial/hgweb/webcommands.py b/mercurial/hgweb/webcommands.py
--- a/mercurial/hgweb/webcommands.py
+++ b/mercurial/hgweb/webcommands.py
@@ -398,14 +398,8 @@
         revs = []
         if pos != -1:
             revs = web.repo.changelog.revs(pos, 0)
-        curcount = 0
-        for rev in revs:
-            curcount += 1
-            if curcount > revcount + 1:
-                break
 
-            entry = webutil.changelistentry(web, web.repo[rev])
-            entry['parity'] = next(parity)
+        for entry in webutil.changelistentries(web, revs, revcount, parity):
             yield entry
 
     if shortlog:



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