repair: use context manager for lock management
If repo.lock() raised inside of the try block, 'tr' would have been None in the
finally block where it tries to release(). Modernize the syntax instead of just
winching the lock out of the try block.
I found several other instances of acquiring the lock inside of the 'try', but
those finally blocks handle None references. I also started switching some
trivial try/finally blocks to context managers, but didn't get them all because
indenting over 3x for lock, wlock and transaction would have spilled over 80
characters. That got me wondering if there should be a repo.rwlock(), to handle
locking and unlocking in the proper order.
It also looks like py27 supports supports multiple context managers for a single
'with' statement. Should I hold off on the rest until py26 is dropped?
# test-batching.py - tests for transparent command batching
#
# Copyright 2011 Peter Arrenbrecht <peter@arrenbrecht.ch>
#
# 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, print_function
from mercurial import (
peer,
wireproto,
)
# equivalent of repo.repository
class thing(object):
def hello(self):
return "Ready."
# equivalent of localrepo.localrepository
class localthing(thing):
def foo(self, one, two=None):
if one:
return "%s and %s" % (one, two,)
return "Nope"
def bar(self, b, a):
return "%s und %s" % (b, a,)
def greet(self, name=None):
return "Hello, %s" % name
def batch(self):
'''Support for local batching.'''
return peer.localbatch(self)
# usage of "thing" interface
def use(it):
# Direct call to base method shared between client and server.
print(it.hello())
# Direct calls to proxied methods. They cause individual roundtrips.
print(it.foo("Un", two="Deux"))
print(it.bar("Eins", "Zwei"))
# Batched call to a couple of (possibly proxied) methods.
batch = it.batch()
# The calls return futures to eventually hold results.
foo = batch.foo(one="One", two="Two")
foo2 = batch.foo(None)
bar = batch.bar("Eins", "Zwei")
# We can call non-batchable proxy methods, but the break the current batch
# request and cause additional roundtrips.
greet = batch.greet(name="John Smith")
# We can also add local methods into the mix, but they break the batch too.
hello = batch.hello()
bar2 = batch.bar(b="Uno", a="Due")
# Only now are all the calls executed in sequence, with as few roundtrips
# as possible.
batch.submit()
# After the call to submit, the futures actually contain values.
print(foo.value)
print(foo2.value)
print(bar.value)
print(greet.value)
print(hello.value)
print(bar2.value)
# local usage
mylocal = localthing()
print()
print("== Local")
use(mylocal)
# demo remoting; mimicks what wireproto and HTTP/SSH do
# shared
def escapearg(plain):
return (plain
.replace(':', '::')
.replace(',', ':,')
.replace(';', ':;')
.replace('=', ':='))
def unescapearg(escaped):
return (escaped
.replace(':=', '=')
.replace(':;', ';')
.replace(':,', ',')
.replace('::', ':'))
# server side
# equivalent of wireproto's global functions
class server(object):
def __init__(self, local):
self.local = local
def _call(self, name, args):
args = dict(arg.split('=', 1) for arg in args)
return getattr(self, name)(**args)
def perform(self, req):
print("REQ:", req)
name, args = req.split('?', 1)
args = args.split('&')
vals = dict(arg.split('=', 1) for arg in args)
res = getattr(self, name)(**vals)
print(" ->", res)
return res
def batch(self, cmds):
res = []
for pair in cmds.split(';'):
name, args = pair.split(':', 1)
vals = {}
for a in args.split(','):
if a:
n, v = a.split('=')
vals[n] = unescapearg(v)
res.append(escapearg(getattr(self, name)(**vals)))
return ';'.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 ''.join(chr(ord(c) + 1) for c in s)
def unmangle(s):
return ''.join(chr(ord(c) - 1) for c in 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 + '?' + '&'.join(['%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 = ','.join(n + '=' + escapearg(v) for n, v in args)
req.append(name + ':' + args)
req = ';'.join(req)
res = self._submitone('batch', [('cmds', req,)])
return res.split(';')
def batch(self):
return wireproto.remotebatch(self)
@peer.batchable
def foo(self, one, two=None):
if not one:
yield "Nope", None
encargs = [('one', mangle(one),), ('two', mangle(two),)]
encresref = peer.future()
yield encargs, encresref
yield unmangle(encresref.value)
@peer.batchable
def bar(self, b, a):
encresref = peer.future()
yield [('b', mangle(b),), ('a', mangle(a),)], encresref
yield unmangle(encresref.value)
# 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('greet', [('name', mangle(name),)]))
# demo remote usage
myproxy = remotething(myserver)
print()
print("== Remote")
use(myproxy)