Mercurial > hg
view mercurial/txnutil.py @ 31796:e0dc40530c5a
zstd: vendor python-zstandard 0.8.0
Commit 81e1f5bbf1fc54808649562d3ed829730765c540 from
https://github.com/indygreg/python-zstandard is imported without
modifications (other than removing unwanted files).
Updates relevant to Mercurial include:
* Support for multi-threaded compression (we can use this for
bundle and wire protocol compression).
* APIs for batch compression and decompression operations using
multiple threads and optimal memory allocation mechanism. (Can
be useful for revlog perf improvements.)
* A ``BufferWithSegments`` type that models a single memory buffer
containing N discrete items of known lengths. This type can be
used for very efficient 0-copy data operations.
# no-check-commit
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 01 Apr 2017 15:24:03 -0700 |
parents | 206532700213 |
children | 2372284d9457 |
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# 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. from __future__ import absolute_import 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('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('%s.pending' % filename, **kwargs), True) except IOError as inst: if inst.errno != errno.ENOENT: raise return (vfs(filename, **kwargs), False)