Mercurial > hg
view tests/fakedirstatewritetime.py @ 27430:e240e914d226 stable
revlog: seek to end of file before writing (issue4943)
Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.
Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.
The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.
Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.
This patch appears to have little to no impact on performance on my
Linux machine.
author | Gregory Szorc <gregory.szorc@gmail.com> |
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date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | 09bb1ee7e73e |
children | b38adef652fe |
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# extension to emulate invoking 'dirstate.write()' at the time # specified by '[fakedirstatewritetime] fakenow', only when # 'dirstate.write()' is invoked via functions below: # # - 'workingctx._checklookup()' (= 'repo.status()') # - 'committablectx.markcommitted()' from mercurial import context, dirstate, extensions, parsers, util def pack_dirstate(fakenow, orig, dmap, copymap, pl, now): # execute what original parsers.pack_dirstate should do actually # for consistency actualnow = int(now) for f, e in dmap.iteritems(): if e[0] == 'n' and e[3] == actualnow: e = parsers.dirstatetuple(e[0], e[1], e[2], -1) dmap[f] = e return orig(dmap, copymap, pl, fakenow) def fakewrite(ui, func): # fake "now" of 'pack_dirstate' only if it is invoked while 'func' fakenow = ui.config('fakedirstatewritetime', 'fakenow') if not fakenow: # Execute original one, if fakenow isn't configured. This is # useful to prevent subrepos from executing replaced one, # because replacing 'parsers.pack_dirstate' is also effective # in subrepos. return func() # parsing 'fakenow' in YYYYmmddHHMM format makes comparison between # 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy fakenow = util.parsedate(fakenow, ['%Y%m%d%H%M'])[0] orig_pack_dirstate = parsers.pack_dirstate orig_dirstate_getfsnow = dirstate._getfsnow wrapper = lambda *args: pack_dirstate(fakenow, orig_pack_dirstate, *args) parsers.pack_dirstate = wrapper dirstate._getfsnow = lambda *args: fakenow try: return func() finally: parsers.pack_dirstate = orig_pack_dirstate dirstate._getfsnow = orig_dirstate_getfsnow def _checklookup(orig, workingctx, files): ui = workingctx.repo().ui return fakewrite(ui, lambda : orig(workingctx, files)) def markcommitted(orig, committablectx, node): ui = committablectx.repo().ui return fakewrite(ui, lambda : orig(committablectx, node)) def extsetup(ui): extensions.wrapfunction(context.workingctx, '_checklookup', _checklookup) extensions.wrapfunction(context.committablectx, 'markcommitted', markcommitted)