Mercurial > hg
view tests/test-lock.py @ 37711:65a23cc8e75b
cborutil: implement support for streaming encoding, bytestring decoding
The vendored cbor2 package is... a bit disappointing.
On the encoding side, it insists that you pass it something with
a write() to send data to. That means if you want to emit data to
a generator, you have to construct an e.g. io.BytesIO(), write()
to it, then get the data back out. There can be non-trivial overhead
involved.
The encoder also doesn't support indefinite types - bytestrings, arrays,
and maps that don't have a known length. Again, this is really
unfortunate because it requires you to buffer the entire source and
destination in memory to encode large things.
On the decoding side, it supports reading indefinite length types.
But it buffers them completely before returning. More sadness.
This commit implements "streaming" encoders for various CBOR types.
Encoding emits a generator of hunks. So you can efficiently stream
encoded data elsewhere.
It also implements support for emitting indefinite length bytestrings,
arrays, and maps.
On the decoding side, we only implement support for decoding an
indefinite length bytestring from a file object. It will emit a
generator of raw chunks from the source.
I didn't want to reinvent so many wheels. But profiling the wire
protocol revealed that the overhead of constructing io.BytesIO()
instances to temporarily hold results has a non-trivial overhead.
We're talking >15% of execution time for operations like
"transfer the fulltexts of all files in a revision." So I can
justify this effort.
Fortunately, CBOR is a relatively straightforward format. And we have
a reference implementation in the repo we can test against.
Differential Revision: https://phab.mercurial-scm.org/D3303
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 14 Apr 2018 16:36:15 -0700 |
parents | daf12f69699f |
children | 5ee3146c1b20 |
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from __future__ import absolute_import import copy import errno import os import silenttestrunner import tempfile import types import unittest from mercurial import ( error, lock, vfs as vfsmod, ) 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.__func__, copy.deepcopy(x.__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 = vfsmod.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) with self.assertRaises(error.LockInheritanceContractViolation): with lock.inherit(): pass lock.release() def testfrequentlockunlock(self): """This tests whether lock acquisition fails as expected, even if (1) lock can't be acquired (makelock fails by EEXIST), and (2) locker info can't be read in (readlock fails by ENOENT) while retrying 5 times. """ d = tempfile.mkdtemp(dir=os.getcwd()) state = teststate(self, d) def emulatefrequentlock(*args): raise OSError(errno.EEXIST, "File exists") def emulatefrequentunlock(*args): raise OSError(errno.ENOENT, "No such file or directory") state.vfs.makelock = emulatefrequentlock state.vfs.readlock = emulatefrequentunlock try: state.makelock(timeout=0) self.fail("unexpected lock acquisition") except error.LockHeld as why: self.assertTrue(why.errno == errno.ETIMEDOUT) self.assertTrue(why.locker == "") state.assertlockexists(False) if __name__ == '__main__': silenttestrunner.main(__name__)