Mercurial > hg
view mercurial/txnutil.py @ 49232:4c57ce494a4e
worker: stop relying on garbage collection to release memoryview
On CPython, before resizing the bytearray, all memoryviews referencing it must
be released. Before this change, we ensured that all references to them were
deleted. On CPython, this was enough to set the reference count to zero, which
results in garbage collecting and releasing them.
On PyPy, releasing the memoryviews is not necessary because they are implemented
differently. If it would be necessary however, ensuring that all references are
deleted would not be suffient because PyPy doesn’t use reference counting.
By using with statements that take care of releasing the memoryviews, we ensure
that the bytearray is resizable without relying on implementation details. So
while this doesn’t fix any observable bug, it increases compatiblity with other
and future Python implementations.
author | Manuel Jacob <me@manueljacob.de> |
---|---|
date | Sat, 21 May 2022 23:31:30 +0200 |
parents | 6000f5b25c9b |
children | 2e726c934fcd |
line wrap: on
line source
# txnutil.py - transaction related utilities # # Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import errno from . import encoding def mayhavepending(root): """return whether 'root' may have pending changes, which are visible to this process. """ return root == encoding.environ.get(b'HG_PENDING') def trypending(root, vfs, filename, **kwargs): """Open file to be read according to HG_PENDING environment variable This opens '.pending' of specified 'filename' only when HG_PENDING is equal to 'root'. This returns '(fp, is_pending_opened)' tuple. """ if mayhavepending(root): try: return (vfs(b'%s.pending' % filename, **kwargs), True) except IOError as inst: if inst.errno != errno.ENOENT: raise return (vfs(filename, **kwargs), False)