view tests/bruterebase.py @ 36367:043e77f3be09

sshpeer: return framed file object when needed

Currently, wireproto.wirepeer has a default implementation of
_submitbatch() and sshv1peer has a very similar implementation.
The main difference is that sshv1peer is aware of the total amount
of bytes it can read whereas the default implementation reads the
stream until no more data is returned. The default implementation
works for HTTP, since there is a known end to HTTP responses (either
Content-Length or 0 sized chunk).

This commit teaches sshv1peer to use our just-introduced "cappedreader"
class for wrapping a file object to limit the number of bytes that
can be read. We do this by introducing an argument to specify whether
the response is framed. If set, we returned a cappedreader instance
instead of the raw pipe.

_call() always has framed responses. So we set this argument
unconditionally and then .read() the entirety of the result.
Strictly speaking, we don't need to use cappedreader in this case
and can inline frame decoding/read logic. But I like when things
are consistent. The overhead should be negligible.

_callstream() and _callcompressable() are special: whether framing
is used depends on the specific command. So, we define a set
of commands that have framed response. It currently only
contains "batch."

As a result of this change, the one-off implementation of
_submitbatch() in sshv1peer can be removed since it is now
safe to .read() the response's file object until end of stream.
cappedreader takes care of not overrunning the frame.

Differential Revision: https://phab.mercurial-scm.org/D2380

# bruterebase.py - brute force rebase testing
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from mercurial import (
    error,
    registrar,
    revsetlang,
)

from hgext import rebase

try:
    xrange
except NameError:
    xrange = range

cmdtable = {}
command = registrar.command(cmdtable)

@command(b'debugbruterebase')
def debugbruterebase(ui, repo, source, dest):
    """for every non-empty subset of source, run rebase -r subset -d dest

    Print one line summary for each subset. Assume obsstore is enabled.
    """
    srevs = list(repo.revs(source))

    with repo.wlock(), repo.lock():
        repolen = len(repo)
        cl = repo.changelog

        def getdesc(rev):
            result = cl.changelogrevision(rev).description
            if rev >= repolen:
                result += b"'"
            return result

        for i in xrange(1, 2 ** len(srevs)):
            subset = [rev for j, rev in enumerate(srevs) if i & (1 << j) != 0]
            spec = revsetlang.formatspec(b'%ld', subset)
            tr = repo.transaction(b'rebase')
            tr.report = lambda x: 0 # hide "transaction abort"

            ui.pushbuffer()
            try:
                rebase.rebase(ui, repo, dest=dest, rev=[spec])
            except error.Abort as ex:
                summary = b'ABORT: %s' % ex
            except Exception as ex:
                summary = b'CRASH: %s' % ex
            else:
                # short summary about new nodes
                cl = repo.changelog
                descs = []
                for rev in xrange(repolen, len(repo)):
                    desc = b'%s:' % getdesc(rev)
                    for prev in cl.parentrevs(rev):
                        if prev > -1:
                            desc += getdesc(prev)
                    descs.append(desc)
                descs.sort()
                summary = ' '.join(descs)
            ui.popbuffer()
            repo.vfs.tryunlink(b'rebasestate')

            subsetdesc = b''.join(getdesc(rev) for rev in subset)
            ui.write((b'%s: %s\n') % (subsetdesc.rjust(len(srevs)), summary))
            tr.abort()