view tests/test-check-interfaces.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

# Test that certain objects conform to well-defined interfaces.

from __future__ import absolute_import, print_function

from mercurial import (
    bundlerepo,
    httppeer,
    localrepo,
    sshpeer,
    statichttprepo,
    ui as uimod,
    unionrepo,
)

def checkobject(o):
    """Verify a constructed object conforms to interface rules.

    An object must have __abstractmethods__ defined.

    All "public" attributes of the object (attributes not prefixed with
    an underscore) must be in __abstractmethods__ or appear on a base class
    with __abstractmethods__.
    """
    name = o.__class__.__name__

    allowed = set()
    for cls in o.__class__.__mro__:
        if not getattr(cls, '__abstractmethods__', set()):
            continue

        allowed |= cls.__abstractmethods__
        allowed |= {a for a in dir(cls) if not a.startswith('_')}

    if not allowed:
        print('%s does not have abstract methods' % name)
        return

    public = {a for a in dir(o) if not a.startswith('_')}

    for attr in sorted(public - allowed):
        print('public attributes not in abstract interface: %s.%s' % (
            name, attr))

# Facilitates testing localpeer.
class dummyrepo(object):
    def __init__(self):
        self.ui = uimod.ui()
    def filtered(self, name):
        pass
    def _restrictcapabilities(self, caps):
        pass

# Facilitates testing sshpeer without requiring an SSH server.
class badpeer(httppeer.httppeer):
    def __init__(self):
        super(badpeer, self).__init__(uimod.ui(), 'http://localhost')
        self.badattribute = True

    def badmethod(self):
        pass

def main():
    ui = uimod.ui()

    checkobject(badpeer())
    checkobject(httppeer.httppeer(ui, 'http://localhost'))
    checkobject(localrepo.localpeer(dummyrepo()))
    checkobject(sshpeer.sshv1peer(ui, 'ssh://localhost/foo', None, None, None,
                                  None, None))
    checkobject(sshpeer.sshv2peer(ui, 'ssh://localhost/foo', None, None, None,
                                  None, None))
    checkobject(bundlerepo.bundlepeer(dummyrepo()))
    checkobject(statichttprepo.statichttppeer(dummyrepo()))
    checkobject(unionrepo.unionpeer(dummyrepo()))

main()