convert: add a mode where mercurial_sink skips empty revisions.
The getchanges function of some converter_source classes can return
some false positives. I.e. they sometimes claim that a file "foo"
was changed in some revision, even though its contents are still the
same.
convert_svn is particularly bad, but I think this can also happen with
convert_cvs and, at least in theory, with mercurial_source.
For regular conversions this is not really a problem - as long as
getfile returns the right contents, we'll get a converted revision
with the right contents. But when we use --filemap, this could lead
to superfluous revisions being converted.
Instead of fixing every converter_source, I decided to change
mercurial_sink to work around this problem.
When --filemap is used, we're interested only in revisions that touch
some specific files. If a revision doesn't change any of these files,
then we're not interested in it (at least for revisions with a single
parent; merges are special).
For mercurial_sink, we abuse this property and rollback a commit if
the manifest text hasn't changed. This avoids duplicating the logic
from localrepo.filecommit to detect unchanged files.
#!/usr/bin/env python
__doc__ = """This does HTTP get requests given a host:port and path and returns
a subset of the headers plus the body of the result."""
import httplib, sys
headers = [h.lower() for h in sys.argv[3:]]
conn = httplib.HTTPConnection(sys.argv[1])
conn.request("GET", sys.argv[2])
response = conn.getresponse()
print response.status, response.reason
for h in headers:
if response.getheader(h, None) is not None:
print "%s: %s" % (h, response.getheader(h))
print
sys.stdout.write(response.read())