hg2git.py: Add simple delta revision feed

Now we have three methods of feeding out changes
  1) full for first revision or
  2) thorough delta for merges (compare checksums with all parents) or
  3) simple delta else (only got with manifest)

This requires some cleanup so that we have only place where we actually
call the appropriate dumping method.

The export_file_contents() method now also sorts its file list before
writing out anything as this seems to speed up hg data retrival a bit.

Signed-off-by: Rocco Rutte <pdmef@gmx.net>

diff --git a/hg2git.py b/hg2git.py
index 966ee63..b411066 100644 (file)
--- a/hg2git.py
+++ b/hg2git.py
@@ -70,7 +70,7 @@ def get_changeset(ui,repo,revision,authors={}):
   (manifest,user,(time,timezone),files,desc,extra)=repo.changelog.read(node)
   tz="%+03d%02d" % (-timezone / 3600, ((-timezone % 3600) / 60))
   branch=get_branch(extra.get('branch','master'))
-  return (manifest,fixup_user(user,authors),(time,tz),files,desc,branch,extra)
+  return (node,manifest,fixup_user(user,authors),(time,tz),files,desc,branch,extra)
 
 def gitmode(x):
   return x and '100755' or '100644'
@@ -167,6 +167,7 @@ def get_author(logmessage,committer,authors):
 
 def export_file_contents(ctx,manifest,files):
   count=0
+  files.sort()
   max=len(files)
   for file in files:
     fctx=ctx.filectx(file)
@@ -180,8 +181,15 @@ def export_file_contents(ctx,manifest,files):
   if max>cfg_export_boundary:
     sys.stderr.write('Exported %d/%d files\n' % (count,max))
 
+def is_merge(parents):
+  c=0
+  for parent in parents:
+    if parent>=0:
+      c+=1
+  return c>1
+
 def export_commit(ui,repo,revision,marks,heads,last,max,count,authors,sob):
-  (_,user,(time,timezone),files,desc,branch,_)=get_changeset(ui,repo,revision,authors)
+  (revnode,_,user,(time,timezone),files,desc,branch,_)=get_changeset(ui,repo,revision,authors)
   parents=repo.changelog.parentrevs(revision)
 
   wr('commit refs/heads/%s' % branch)
@@ -236,22 +244,33 @@ def export_commit(ui,repo,revision,marks,heads,last,max,count,authors,sob):
 
   ctx=repo.changectx(str(revision))
   man=ctx.manifest()
+  added,changed,removed,type=[],[],[],''
 
   if revision==0:
     # first revision: feed in full manifest
-    sys.stderr.write('Exporting full revision %d/%d with %d added files\n' %
-        (revision+1,max,len(man.keys())))
-    export_file_contents(ctx,man,man.keys())
-  else:
-    # later revision: feed in changed manifest
+    added=man.keys()
+    type='full'
+  elif is_merge(parents):
+    # later merge revision: feed in changed manifest
+    # for many files comparing checksums is expensive so only do it for
+    # merges where we really need it due to hg's revlog logic
     added,changed,removed=get_filechanges(repo,revision,parents,man)
-    sys.stderr.write('Exporting delta revision %d/%d with %d/%d/%d added/changed/removed files\n' %
-        (revision+1,max,len(added),len(changed),len(removed)))
-    export_file_contents(ctx,man,added+changed)
-    for r in removed:
-      wr('D %s' % r)
-
+    type='thorough delta'
+  else:
+    # later non-merge revision: feed in changed manifest
+    # if we have exactly one parent, just take the changes from the
+    # manifest without expensively comparing checksums
+    f=repo.status(repo.lookup(parents[0]),revnode)[:3]
+    added,changed,removed=f[1],f[0],f[2]
+    type='simple delta'
+
+  sys.stderr.write('Exporting %s revision %d/%d with %d/%d/%d added/changed/removed files\n' %
+      (type,revision+1,max,len(added),len(changed),len(removed)))
+
+  map(lambda r: wr('D %s' % r),removed)
+  export_file_contents(ctx,man,added+changed)
   wr()
+
   return checkpoint(count)
 
 def export_tags(ui,repo,marks_cache,start,end,count,authors):
@@ -344,7 +363,7 @@ def verify_heads(ui,repo,cache,force):
   # verify that branch has exactly one head
   t={}
   for h in repo.heads():
-    (_,_,_,_,_,branch,_)=get_changeset(ui,repo,h)
+    (_,_,_,_,_,_,branch,_)=get_changeset(ui,repo,h)
     if t.get(branch,False):
       sys.stderr.write('Error: repository has at least one unnamed head: hg r%s\n' %
           repo.changelog.rev(h))