exchange: refactor APIs to obtain bundle data (API)
Currently, exchange.getbundle() returns either a cg1unpacker or a
util.chunkbuffer (in the case of bundle2). This is kinda OK, as
both expose a .read() to consumers. However, localpeer.getbundle()
has code inferring what the response type is based on arguments and
converts the util.chunkbuffer returned in the bundle2 case to a
bundle2.unbundle20 instance. This is a sign that the API for
exchange.getbundle() is not ideal because it doesn't consistently
return an "unbundler" instance.
In addition, unbundlers mask the fact that there is an underlying
generator of changegroup data. In both cg1 and bundle2, this generator
is being fed into a util.chunkbuffer so it can be re-exposed as a
file object.
util.chunkbuffer is a nice abstraction. However, it should only be
used "at the edges." This is because keeping data as a generator is
more efficient than converting it to a chunkbuffer, especially if we
convert that chunkbuffer back to a generator (as is the case in some
code paths currently).
This patch refactors exchange.getbundle() into
exchange.getbundlechunks(). The new API returns an iterator of chunks
instead of a file-like object.
Callers of exchange.getbundle() have been updated to use the new API.
There is a minor change of behavior in test-getbundle.t. This is
because `hg debuggetbundle` isn't defining bundlecaps. As a result,
a cg1 data stream and unpacker is being produced. This is getting fed
into a new bundle20 instance via bundle2.writebundle(), which uses
a backchannel mechanism between changegroup generation to add the
"nbchanges" part parameter. I never liked this backchannel mechanism
and I plan to remove it someday. `hg bundle` still produces the
"nbchanges" part parameter, so there should be no user-visible
change of behavior. I consider this "regression" a bug in
`hg debuggetbundle`. And that bug is captured by an existing
"TODO" in the code to use bundle2 capabilities.
from __future__ import absolute_import
import copy
import os
import silenttestrunner
import tempfile
import types
import unittest
from mercurial import (
error,
lock,
scmutil,
)
testlockname = 'testlock'
# work around http://bugs.python.org/issue1515
if types.MethodType not in copy._deepcopy_dispatch:
def _deepcopy_method(x, memo):
return type(x)(x.im_func, copy.deepcopy(x.im_self, memo), x.im_class)
copy._deepcopy_dispatch[types.MethodType] = _deepcopy_method
class lockwrapper(lock.lock):
def __init__(self, pidoffset, *args, **kwargs):
# lock.lock.__init__() calls lock(), so the pidoffset assignment needs
# to be earlier
self._pidoffset = pidoffset
super(lockwrapper, self).__init__(*args, **kwargs)
def _getpid(self):
return super(lockwrapper, self)._getpid() + self._pidoffset
class teststate(object):
def __init__(self, testcase, dir, pidoffset=0):
self._testcase = testcase
self._acquirecalled = False
self._releasecalled = False
self._postreleasecalled = False
self.vfs = scmutil.vfs(dir, audit=False)
self._pidoffset = pidoffset
def makelock(self, *args, **kwargs):
l = lockwrapper(self._pidoffset, self.vfs, testlockname,
releasefn=self.releasefn, acquirefn=self.acquirefn,
*args, **kwargs)
l.postrelease.append(self.postreleasefn)
return l
def acquirefn(self):
self._acquirecalled = True
def releasefn(self):
self._releasecalled = True
def postreleasefn(self):
self._postreleasecalled = True
def assertacquirecalled(self, called):
self._testcase.assertEqual(
self._acquirecalled, called,
'expected acquire to be %s but was actually %s' % (
self._tocalled(called),
self._tocalled(self._acquirecalled),
))
def resetacquirefn(self):
self._acquirecalled = False
def assertreleasecalled(self, called):
self._testcase.assertEqual(
self._releasecalled, called,
'expected release to be %s but was actually %s' % (
self._tocalled(called),
self._tocalled(self._releasecalled),
))
def assertpostreleasecalled(self, called):
self._testcase.assertEqual(
self._postreleasecalled, called,
'expected postrelease to be %s but was actually %s' % (
self._tocalled(called),
self._tocalled(self._postreleasecalled),
))
def assertlockexists(self, exists):
actual = self.vfs.lexists(testlockname)
self._testcase.assertEqual(
actual, exists,
'expected lock to %s but actually did %s' % (
self._toexists(exists),
self._toexists(actual),
))
def _tocalled(self, called):
if called:
return 'called'
else:
return 'not called'
def _toexists(self, exists):
if exists:
return 'exist'
else:
return 'not exist'
class testlock(unittest.TestCase):
def testlock(self):
state = teststate(self, tempfile.mkdtemp(dir=os.getcwd()))
lock = state.makelock()
state.assertacquirecalled(True)
lock.release()
state.assertreleasecalled(True)
state.assertpostreleasecalled(True)
state.assertlockexists(False)
def testrecursivelock(self):
state = teststate(self, tempfile.mkdtemp(dir=os.getcwd()))
lock = state.makelock()
state.assertacquirecalled(True)
state.resetacquirefn()
lock.lock()
# recursive lock should not call acquirefn again
state.assertacquirecalled(False)
lock.release() # brings lock refcount down from 2 to 1
state.assertreleasecalled(False)
state.assertpostreleasecalled(False)
state.assertlockexists(True)
lock.release() # releases the lock
state.assertreleasecalled(True)
state.assertpostreleasecalled(True)
state.assertlockexists(False)
def testlockfork(self):
state = teststate(self, tempfile.mkdtemp(dir=os.getcwd()))
lock = state.makelock()
state.assertacquirecalled(True)
# fake a fork
forklock = copy.deepcopy(lock)
forklock._pidoffset = 1
forklock.release()
state.assertreleasecalled(False)
state.assertpostreleasecalled(False)
state.assertlockexists(True)
# release the actual lock
lock.release()
state.assertreleasecalled(True)
state.assertpostreleasecalled(True)
state.assertlockexists(False)
def testinheritlock(self):
d = tempfile.mkdtemp(dir=os.getcwd())
parentstate = teststate(self, d)
parentlock = parentstate.makelock()
parentstate.assertacquirecalled(True)
# set up lock inheritance
with parentlock.inherit() as lockname:
parentstate.assertreleasecalled(True)
parentstate.assertpostreleasecalled(False)
parentstate.assertlockexists(True)
childstate = teststate(self, d, pidoffset=1)
childlock = childstate.makelock(parentlock=lockname)
childstate.assertacquirecalled(True)
childlock.release()
childstate.assertreleasecalled(True)
childstate.assertpostreleasecalled(False)
childstate.assertlockexists(True)
parentstate.resetacquirefn()
parentstate.assertacquirecalled(True)
parentlock.release()
parentstate.assertreleasecalled(True)
parentstate.assertpostreleasecalled(True)
parentstate.assertlockexists(False)
def testmultilock(self):
d = tempfile.mkdtemp(dir=os.getcwd())
state0 = teststate(self, d)
lock0 = state0.makelock()
state0.assertacquirecalled(True)
with lock0.inherit() as lock0name:
state0.assertreleasecalled(True)
state0.assertpostreleasecalled(False)
state0.assertlockexists(True)
state1 = teststate(self, d, pidoffset=1)
lock1 = state1.makelock(parentlock=lock0name)
state1.assertacquirecalled(True)
# from within lock1, acquire another lock
with lock1.inherit() as lock1name:
# since the file on disk is lock0's this should have the same
# name
self.assertEqual(lock0name, lock1name)
state2 = teststate(self, d, pidoffset=2)
lock2 = state2.makelock(parentlock=lock1name)
state2.assertacquirecalled(True)
lock2.release()
state2.assertreleasecalled(True)
state2.assertpostreleasecalled(False)
state2.assertlockexists(True)
state1.resetacquirefn()
state1.assertacquirecalled(True)
lock1.release()
state1.assertreleasecalled(True)
state1.assertpostreleasecalled(False)
state1.assertlockexists(True)
lock0.release()
def testinheritlockfork(self):
d = tempfile.mkdtemp(dir=os.getcwd())
parentstate = teststate(self, d)
parentlock = parentstate.makelock()
parentstate.assertacquirecalled(True)
# set up lock inheritance
with parentlock.inherit() as lockname:
childstate = teststate(self, d, pidoffset=1)
childlock = childstate.makelock(parentlock=lockname)
childstate.assertacquirecalled(True)
# fork the child lock
forkchildlock = copy.deepcopy(childlock)
forkchildlock._pidoffset += 1
forkchildlock.release()
childstate.assertreleasecalled(False)
childstate.assertpostreleasecalled(False)
childstate.assertlockexists(True)
# release the child lock
childlock.release()
childstate.assertreleasecalled(True)
childstate.assertpostreleasecalled(False)
childstate.assertlockexists(True)
parentlock.release()
def testinheritcheck(self):
d = tempfile.mkdtemp(dir=os.getcwd())
state = teststate(self, d)
def check():
raise error.LockInheritanceContractViolation('check failed')
lock = state.makelock(inheritchecker=check)
state.assertacquirecalled(True)
def tryinherit():
with lock.inherit():
pass
self.assertRaises(error.LockInheritanceContractViolation, tryinherit)
lock.release()
if __name__ == '__main__':
silenttestrunner.main(__name__)