Mercurial > hg
view mercurial/state.py @ 41247:a89b20a49c13
rust-cpython: using MissingAncestors from Python code
As precedently done with LazyAncestors on cpython.rs, we test for the
presence of the 'rustext' module.
incrementalmissingrevs() has two callers within the Mercurial core:
`setdiscovery.partialdiscovery` and the `only()` revset.
This move shows a significant discovery performance improvement
in cases where the baseline is slow: using perfdiscovery on the PyPy
repos, prepared with `contrib/discovery-helper <repo> 50 100`, we
get averaged medians of 403ms with the Rust version vs 742ms without
(about 45% better).
But there are still indications that performance can be worse in cases
the baseline is fast, possibly due to the conversion from Python to
Rust and back becoming the bottleneck. We could measure this on
mozilla-central in cases were the delta is just a few changesets.
This requires confirmation, but if that's the reason, then an
upcoming `partialdiscovery` fully in Rust should solve the problem.
Differential Revision: https://phab.mercurial-scm.org/D5551
author | Georges Racinet <georges.racinet@octobus.net> |
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date | Fri, 30 Nov 2018 14:35:57 +0100 |
parents | 050ea8eb42a5 |
children | 5f2f6912c9e6 |
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# state.py - writing and reading state files in Mercurial # # Copyright 2018 Pulkit Goyal <pulkitmgoyal@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """ This file contains class to wrap the state for commands and other related logic. All the data related to the command state is stored as dictionary in the object. The class has methods using which the data can be stored to disk in a file under .hg/ directory. We store the data on disk in cbor, for which we use the CBOR format to encode the data. """ from __future__ import absolute_import from . import ( error, util, ) from .utils import ( cborutil, ) class cmdstate(object): """a wrapper class to store the state of commands like `rebase`, `graft`, `histedit`, `shelve` etc. Extensions can also use this to write state files. All the data for the state is stored in the form of key-value pairs in a dictionary. The class object can write all the data to a file in .hg/ directory and can populate the object data reading that file. Uses cbor to serialize and deserialize data while writing and reading from disk. """ def __init__(self, repo, fname): """ repo is the repo object fname is the file name in which data should be stored in .hg directory """ self._repo = repo self.fname = fname def read(self): """read the existing state file and return a dict of data stored""" return self._read() def save(self, version, data): """write all the state data stored to .hg/<filename> file we use third-party library cbor to serialize data to write in the file. """ if not isinstance(version, int): raise error.ProgrammingError("version of state file should be" " an integer") with self._repo.vfs(self.fname, 'wb', atomictemp=True) as fp: fp.write('%d\n' % version) for chunk in cborutil.streamencode(data): fp.write(chunk) def _read(self): """reads the state file and returns a dictionary which contain data in the same format as it was before storing""" with self._repo.vfs(self.fname, 'rb') as fp: try: int(fp.readline()) except ValueError: raise error.CorruptedState("unknown version of state file" " found") return cborutil.decodeall(fp.read())[0] def delete(self): """drop the state file if exists""" util.unlinkpath(self._repo.vfs.join(self.fname), ignoremissing=True) def exists(self): """check whether the state file exists or not""" return self._repo.vfs.exists(self.fname)