view tests/test-batching.py @ 51930:bc9ed92d4753

util: make `mmapread()` work on Windows again

522b4d729e89 started referencing `mmap.MAP_PRIVATE`, but that's not available on
Windows, so `hg version` worked, but `make local` did not.  That commit also
started calling the constructor with the fine-grained `flags` and `prot` args,
but those aren't available on Windows either[1] (though the backing C code
doesn't seem conditionalized to disallow usage of them).

I assume the change away from from the `access` arg was to provide the same
options, plus `MAP_POPULATE`.  Looking at the source code[2], they're not quite
the same- `ACCESS_READ` is equivalent to `flags = MAP_SHARED` and `prot = PROT_READ`.
`MAP_PRIVATE` is only used with `ACCESS_COPY`, which allows read and write.
Therefore, we can't quite get the same baseline flags on Windows, but this was
the status quo ante and `MAP_POPULATE` is a Linux thing, so presumably it works.

I realize that typically the OS differences are abstracted into the platform
modules, but I'm leaving it here so that it is obvious what the differences are
between the platforms.

[1] https://docs.python.org/3/library/mmap.html#mmap.mmap
[2] https://github.com/python/cpython/blob/5e0abb47886bc665eefdcc19fde985f803e49d4c/Modules/mmapmodule.c#L1539

# test-batching.py - tests for transparent command batching
#
# Copyright 2011 Peter Arrenbrecht <[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.


import contextlib

from mercurial import (
    localrepo,
    pycompat,
    wireprotov1peer,
)


def bprint(*bs):
    print(*[pycompat.sysstr(b) for b in bs])


# equivalent of repo.repository
class thing:
    def hello(self):
        return b"Ready."


# equivalent of localrepo.localrepository
class localthing(thing):
    def foo(self, one, two=None):
        if one:
            return b"%s and %s" % (
                one,
                two,
            )
        return b"Nope"

    def bar(self, b, a):
        return b"%s und %s" % (
            b,
            a,
        )

    def greet(self, name=None):
        return b"Hello, %s" % name

    @contextlib.contextmanager
    def commandexecutor(self):
        e = localrepo.localcommandexecutor(self)
        try:
            yield e
        finally:
            e.close()


# usage of "thing" interface
def use(it):
    # Direct call to base method shared between client and server.
    bprint(it.hello())

    # Direct calls to proxied methods. They cause individual roundtrips.
    bprint(it.foo(b"Un", two=b"Deux"))
    bprint(it.bar(b"Eins", b"Zwei"))

    # Batched call to a couple of proxied methods.

    with it.commandexecutor() as e:
        ffoo = e.callcommand(b'foo', {b'one': b'One', b'two': b'Two'})
        fbar = e.callcommand(b'bar', {b'b': b'Eins', b'a': b'Zwei'})
        fbar2 = e.callcommand(b'bar', {b'b': b'Uno', b'a': b'Due'})

    bprint(ffoo.result())
    bprint(fbar.result())
    bprint(fbar2.result())


# local usage
mylocal = localthing()
print()
bprint(b"== Local")
use(mylocal)

# demo remoting; mimicks what wireproto and HTTP/SSH do

# shared


def escapearg(plain):
    return (
        plain.replace(b':', b'::')
        .replace(b',', b':,')
        .replace(b';', b':;')
        .replace(b'=', b':=')
    )


def unescapearg(escaped):
    return (
        escaped.replace(b':=', b'=')
        .replace(b':;', b';')
        .replace(b':,', b',')
        .replace(b'::', b':')
    )


# server side


# equivalent of wireproto's global functions
class server:
    def __init__(self, local):
        self.local = local

    def _call(self, name, args):
        args = dict(arg.split(b'=', 1) for arg in args)
        return getattr(self, name)(**args)

    def perform(self, req):
        bprint(b"REQ:", req)
        name, args = req.split(b'?', 1)
        args = args.split(b'&')
        vals = dict(arg.split(b'=', 1) for arg in args)
        res = getattr(self, pycompat.sysstr(name))(**pycompat.strkwargs(vals))
        bprint(b"  ->", res)
        return res

    def batch(self, cmds):
        res = []
        for pair in cmds.split(b';'):
            name, args = pair.split(b':', 1)
            vals = {}
            for a in args.split(b','):
                if a:
                    n, v = a.split(b'=')
                    vals[n] = unescapearg(v)
            res.append(
                escapearg(
                    getattr(self, pycompat.sysstr(name))(
                        **pycompat.strkwargs(vals)
                    )
                )
            )
        return b';'.join(res)

    def foo(self, one, two):
        return mangle(self.local.foo(unmangle(one), unmangle(two)))

    def bar(self, b, a):
        return mangle(self.local.bar(unmangle(b), unmangle(a)))

    def greet(self, name):
        return mangle(self.local.greet(unmangle(name)))


myserver = server(mylocal)

# local side


# equivalent of wireproto.encode/decodelist, that is, type-specific marshalling
# here we just transform the strings a bit to check we're properly en-/decoding
def mangle(s):
    return b''.join(pycompat.bytechr(ord(c) + 1) for c in pycompat.bytestr(s))


def unmangle(s):
    return b''.join(pycompat.bytechr(ord(c) - 1) for c in pycompat.bytestr(s))


# equivalent of wireproto.wirerepository and something like http's wire format
class remotething(thing):
    def __init__(self, server):
        self.server = server

    def _submitone(self, name, args):
        req = name + b'?' + b'&'.join([b'%s=%s' % (n, v) for n, v in args])
        return self.server.perform(req)

    def _submitbatch(self, cmds):
        req = []
        for name, args in cmds:
            args = b','.join(n + b'=' + escapearg(v) for n, v in args)
            req.append(name + b':' + args)
        req = b';'.join(req)
        res = self._submitone(
            b'batch',
            [
                (
                    b'cmds',
                    req,
                )
            ],
        )
        for r in res.split(b';'):
            yield r

    @contextlib.contextmanager
    def commandexecutor(self):
        e = wireprotov1peer.peerexecutor(self)
        try:
            yield e
        finally:
            e.close()

    @wireprotov1peer.batchable
    def foo(self, one, two=None):
        encoded_args = [
            (
                b'one',
                mangle(one),
            ),
            (
                b'two',
                mangle(two),
            ),
        ]
        return encoded_args, unmangle

    @wireprotov1peer.batchable
    def bar(self, b, a):
        return [
            (
                b'b',
                mangle(b),
            ),
            (
                b'a',
                mangle(a),
            ),
        ], unmangle

    # greet is coded directly. It therefore does not support batching. If it
    # does appear in a batch, the batch is split around greet, and the call to
    # greet is done in its own roundtrip.
    def greet(self, name=None):
        return unmangle(
            self._submitone(
                b'greet',
                [
                    (
                        b'name',
                        mangle(name),
                    )
                ],
            )
        )


# demo remote usage

myproxy = remotething(myserver)
print()
bprint(b"== Remote")
use(myproxy)