Mercurial > hg
view tests/autodiff.py @ 38893:23d582caae30
changegroup: capture revision delta in a data structure
The current changegroup generation code is tightly coupled to
the revlog API. This tight coupling makes it difficult to implement
alternate storage backends without requiring a large surface area
of the revlog API to be exposed. This is not desirable.
In order to support changegroup generation with non-revlog storage,
we'll need to abstract the concept of delta generation.
This commit is the first step down that road. We introduce a
data structure for representing a delta in a changegroup.
The API still leaves a lot to be desired. But at least we now
have separation between data and actions performed on it.
As part of this, we tweak behavior slightly: we no longer
concatenate the delta prefix with the metadata header. Instead,
we track and emit the prefix as a separate chunk. This shouldn't
have any meaningful impact since all the chunks just get sent to
the wire, the compressor, etc.
Because we're introducing a new object, this does add some
overhead to changegroup execution. `hg perfchangegroupchangelog`
on my clone of the Mercurial repo (~40,000 visible revisions in
the changelog) slows down a bit:
! wall 1.268600 comb 1.270000 user 1.270000 sys 0.000000 (best of 8)
! wall 1.419479 comb 1.410000 user 1.410000 sys 0.000000 (best of 8)
With for `hg bundle -t none-v2 -a /dev/null`:
before: real 6.610 secs (user 6.460+0.000 sys 0.140+0.000)
after: real 7.210 secs (user 7.060+0.000 sys 0.140+0.000)
I plan to claw back this regression in future commits. And I may
even do away with this data structure once the refactor is complete.
For now, it makes things easier to comprehend.
Differential Revision: https://phab.mercurial-scm.org/D4075
author | Gregory Szorc <gregory.szorc@gmail.com> |
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date | Fri, 03 Aug 2018 10:05:26 -0700 |
parents | cdccfe20eed7 |
children | 2372284d9457 |
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# Extension dedicated to test patch.diff() upgrade modes from __future__ import absolute_import from mercurial import ( error, patch, pycompat, registrar, scmutil, ) cmdtable = {} command = registrar.command(cmdtable) @command(b'autodiff', [(b'', b'git', b'', b'git upgrade mode (yes/no/auto/warn/abort)')], b'[OPTION]... [FILE]...') def autodiff(ui, repo, *pats, **opts): opts = pycompat.byteskwargs(opts) diffopts = patch.difffeatureopts(ui, opts) git = opts.get(b'git', b'no') brokenfiles = set() losedatafn = None if git in (b'yes', b'no'): diffopts.git = git == b'yes' diffopts.upgrade = False elif git == b'auto': diffopts.git = False diffopts.upgrade = True elif git == b'warn': diffopts.git = False diffopts.upgrade = True def losedatafn(fn=None, **kwargs): brokenfiles.add(fn) return True elif git == b'abort': diffopts.git = False diffopts.upgrade = True def losedatafn(fn=None, **kwargs): raise error.Abort(b'losing data for %s' % fn) else: raise error.Abort(b'--git must be yes, no or auto') ctx1, ctx2 = scmutil.revpair(repo, []) m = scmutil.match(ctx2, pats, opts) it = patch.diff(repo, ctx1.node(), ctx2.node(), match=m, opts=diffopts, losedatafn=losedatafn) for chunk in it: ui.write(chunk) for fn in sorted(brokenfiles): ui.write((b'data lost for: %s\n' % fn))