Mercurial > hg
view mercurial/dirstateguard.py @ 47093:787ff5d21bcd
dirstate-tree: Make Rust DirstateMap bindings go through a trait object
This changeset starts a series that adds an experiment to make status faster
by changing the dirstate (first only in memory and later also on disk) to
be shaped as a tree matching the directory structure, instead of the current
flat collection of entries. The status algorithm can then traverse this tree
dirstate at the same time as it traverses the filesystem.
We (Octobus) have made prototypes that show promising results but are prone
to bitrot. We would like to start upstreaming some experimental Rust code that
goes in this direction, but to avoid disrupting users it should only be
enabled by some run-time opt-in while keeping the existing dirstate structure
and status algorithm as-is.
The `DirstateMap` type and `status` function look like the appropriate
boundary. This adds a new trait that abstracts everything Python bindings need
and makes those bindings go through a `dyn` trait object. Later we’ll have two
implementations of this trait, and the same bindings can use either.
Differential Revision: https://phab.mercurial-scm.org/D10362
author | Simon Sapin <simon.sapin@octobus.net> |
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date | Tue, 30 Mar 2021 14:15:23 +0200 |
parents | 222a42ac5b2d |
children | 6000f5b25c9b |
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# dirstateguard.py - class to allow restoring dirstate after failure # # Copyright 2005-2007 Olivia Mackall <olivia@selenic.com> # # 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 os from .i18n import _ from . import ( error, narrowspec, requirements, util, ) class dirstateguard(util.transactional): """Restore dirstate at unexpected failure. At the construction, this class does: - write current ``repo.dirstate`` out, and - save ``.hg/dirstate`` into the backup file This restores ``.hg/dirstate`` from backup file, if ``release()`` is invoked before ``close()``. This just removes the backup file at ``close()`` before ``release()``. """ def __init__(self, repo, name): self._repo = repo self._active = False self._closed = False def getname(prefix): fd, fname = repo.vfs.mkstemp(prefix=prefix) os.close(fd) return fname self._backupname = getname(b'dirstate.backup.%s.' % name) repo.dirstate.savebackup(repo.currenttransaction(), self._backupname) # Don't make this the empty string, things may join it with stuff and # blindly try to unlink it, which could be bad. self._narrowspecbackupname = None if requirements.NARROW_REQUIREMENT in repo.requirements: self._narrowspecbackupname = getname( b'narrowspec.backup.%s.' % name ) narrowspec.savewcbackup(repo, self._narrowspecbackupname) self._active = True def __del__(self): if self._active: # still active # this may occur, even if this class is used correctly: # for example, releasing other resources like transaction # may raise exception before ``dirstateguard.release`` in # ``release(tr, ....)``. self._abort() def close(self): if not self._active: # already inactivated msg = ( _(b"can't close already inactivated backup: %s") % self._backupname ) raise error.Abort(msg) self._repo.dirstate.clearbackup( self._repo.currenttransaction(), self._backupname ) if self._narrowspecbackupname: narrowspec.clearwcbackup(self._repo, self._narrowspecbackupname) self._active = False self._closed = True def _abort(self): if self._narrowspecbackupname: narrowspec.restorewcbackup(self._repo, self._narrowspecbackupname) self._repo.dirstate.restorebackup( self._repo.currenttransaction(), self._backupname ) self._active = False def release(self): if not self._closed: if not self._active: # already inactivated msg = ( _(b"can't release already inactivated backup: %s") % self._backupname ) raise error.Abort(msg) self._abort()