existing clone code uses pull to get changes from remote repo. is very
slow, uses lots of memory and cpu.
new clone code has server write file data straight to client, client
writes file data straight to disk. memory and cpu used are very low,
clone is much faster over lan.
new client can still clone with pull, can still clone from older servers.
new server can still serve older clients.
The urllib2 differences between python 2.3 and 2.4 are hidden by
using keepalive.py, which also gives us support for persistent
connections.
Support for HTTPS is enabled only if there's a HTTPSHandler class in
urllib2.
It's not possible to have separate classes as handlers for HTTP and
HTTPS: to support persistent HTTPS connections, we need a class that
inherits from both keepalive.HTTPHandler and urllib2.HTTPSHandler. If
we try to pass (an instance of) this class and (an instance of) the
httphandler class to urllib2.build_opener, this function ends up getting
confused, since both classes are subclasses of the HTTPHandler default
handler, and raises an exception.
now all repositories have capabilities slot, tuple with list of names.
if 'unbundle' capability present, repo supports push where client does
not need to lock server. repository classes that have unbundle capability
also have unbundle method.
implemented for ssh now, will be base for push over http.
unbundle protocol acts this way. server tells client what heads it
has during normal negotiate step. client starts unbundle by repeat
server's heads back to it. if server has new heads, abort immediately.
otherwise, transfer changes to server. once data transferred, server
locks and checks heads again. if heads same, changes can be added.
else someone else added heads, and server aborts.
if client wants to force server to add heads, sends special heads list of
'force'.
uses keepalive module from urlgrabber package. tested against "hg serve",
cgi server, and through http proxy. used ethereal to verify that only
one tcp connection used during entire "hg pull" sequence.
if server supports keepalive, this makes latency of "hg pull" much lower.
problems fixed:
- https scheme handled properly for real and proxy urls.
- url of form "http://user:password@host:port/path" now ok.
- no-proxy check uses proper host names.
in interactive mode, mercurial now asks the user for the username and
password when the server requires it. the previous behavior was to fail
with an http 401.
based on patch from eric jaffe <jaffe.eric@gmail.com>.
If the server dies very early, an httplib.IncompleteRead exception may be
raised, because httplib can't read a single byte. Catching all HTTPException
subclasses here will prevent ugly backtraces for similar things, too.