view mercurial/peer.py @ 35935:00b9e26d727b

sshpeer: establish SSH connection before class instantiation

We want to move the handshake to before peers are created so
we can instantiate a different peer class depending on the
results of the handshake. This necessitates moving the SSH
process invocation to outside the peer class.

As part of the code move, some variables were renamed for
clarity. util.popen4() returns stdin, stdout, and stderr in
their typical file descriptor order. However, stdin and stdout
were being mapped to "pipeo" and "pipei" respectively. "o"
for "stdin" and "i" for "stdout" is a bit confusing. Although
it does make sense for "output" and "input" from the perspective
of the client. But in the context of the new function, it makes
sense to refer to these as their file descriptor names.

In addition, the last use of self._path disappeared, so we stop
setting that attribute and we can delete the redundant URL
parsing necessary to set it.

Differential Revision: https://phab.mercurial-scm.org/D2031

# peer.py - repository base classes for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
# Copyright 2006 Vadim Gelfer <[e-mail]>
#
# 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 . import (
    error,
    pycompat,
    util,
)

# abstract batching support

class future(object):
    '''placeholder for a value to be set later'''
    def set(self, value):
        if util.safehasattr(self, 'value'):
            raise error.RepoError("future is already set")
        self.value = value

class batcher(object):
    '''base class for batches of commands submittable in a single request

    All methods invoked on instances of this class are simply queued and
    return a a future for the result. Once you call submit(), all the queued
    calls are performed and the results set in their respective futures.
    '''
    def __init__(self):
        self.calls = []
    def __getattr__(self, name):
        def call(*args, **opts):
            resref = future()
            # Please don't invent non-ascii method names, or you will
            # give core hg a very sad time.
            self.calls.append((name.encode('ascii'), args, opts, resref,))
            return resref
        return call
    def submit(self):
        raise NotImplementedError()

class iterbatcher(batcher):

    def submit(self):
        raise NotImplementedError()

    def results(self):
        raise NotImplementedError()

class localiterbatcher(iterbatcher):
    def __init__(self, local):
        super(iterbatcher, self).__init__()
        self.local = local

    def submit(self):
        # submit for a local iter batcher is a noop
        pass

    def results(self):
        for name, args, opts, resref in self.calls:
            resref.set(getattr(self.local, name)(*args, **opts))
            yield resref.value

def batchable(f):
    '''annotation for batchable methods

    Such methods must implement a coroutine as follows:

    @batchable
    def sample(self, one, two=None):
        # Build list of encoded arguments suitable for your wire protocol:
        encargs = [('one', encode(one),), ('two', encode(two),)]
        # Create future for injection of encoded result:
        encresref = future()
        # Return encoded arguments and future:
        yield encargs, encresref
        # Assuming the future to be filled with the result from the batched
        # request now. Decode it:
        yield decode(encresref.value)

    The decorator returns a function which wraps this coroutine as a plain
    method, but adds the original method as an attribute called "batchable",
    which is used by remotebatch to split the call into separate encoding and
    decoding phases.
    '''
    def plain(*args, **opts):
        batchable = f(*args, **opts)
        encargsorres, encresref = next(batchable)
        if not encresref:
            return encargsorres # a local result in this case
        self = args[0]
        cmd = pycompat.bytesurl(f.__name__)  # ensure cmd is ascii bytestr
        encresref.set(self._submitone(cmd, encargsorres))
        return next(batchable)
    setattr(plain, 'batchable', f)
    return plain