Mercurial > hg
view tests/test-filecache.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> |
---|---|
date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | ce26928cbe41 |
children | fc5f548393bf |
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import sys, os, subprocess if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'], 'cacheable']): sys.exit(80) from mercurial import util, scmutil, extensions, hg, ui filecache = scmutil.filecache class fakerepo(object): def __init__(self): self._filecache = {} def join(self, p): return p def sjoin(self, p): return p @filecache('x', 'y') def cached(self): print 'creating' return 'string from function' def invalidate(self): for k in self._filecache: try: delattr(self, k) except AttributeError: pass def basic(repo): print "* neither file exists" # calls function repo.cached repo.invalidate() print "* neither file still exists" # uses cache repo.cached # create empty file f = open('x', 'w') f.close() repo.invalidate() print "* empty file x created" # should recreate the object repo.cached f = open('x', 'w') f.write('a') f.close() repo.invalidate() print "* file x changed size" # should recreate the object repo.cached repo.invalidate() print "* nothing changed with either file" # stats file again, reuses object repo.cached # atomic replace file, size doesn't change # hopefully st_mtime doesn't change as well so this doesn't use the cache # because of inode change f = scmutil.opener('.')('x', 'w', atomictemp=True) f.write('b') f.close() repo.invalidate() print "* file x changed inode" repo.cached # create empty file y f = open('y', 'w') f.close() repo.invalidate() print "* empty file y created" # should recreate the object repo.cached f = open('y', 'w') f.write('A') f.close() repo.invalidate() print "* file y changed size" # should recreate the object repo.cached f = scmutil.opener('.')('y', 'w', atomictemp=True) f.write('B') f.close() repo.invalidate() print "* file y changed inode" repo.cached f = scmutil.opener('.')('x', 'w', atomictemp=True) f.write('c') f.close() f = scmutil.opener('.')('y', 'w', atomictemp=True) f.write('C') f.close() repo.invalidate() print "* both files changed inode" repo.cached def fakeuncacheable(): def wrapcacheable(orig, *args, **kwargs): return False def wrapinit(orig, *args, **kwargs): pass originit = extensions.wrapfunction(util.cachestat, '__init__', wrapinit) origcacheable = extensions.wrapfunction(util.cachestat, 'cacheable', wrapcacheable) for fn in ['x', 'y']: try: os.remove(fn) except OSError: pass basic(fakerepo()) util.cachestat.cacheable = origcacheable util.cachestat.__init__ = originit def test_filecache_synced(): # test old behavior that caused filecached properties to go out of sync os.system('hg init && echo a >> a && hg ci -qAm.') repo = hg.repository(ui.ui()) # first rollback clears the filecache, but changelog to stays in __dict__ repo.rollback() repo.commit('.') # second rollback comes along and touches the changelog externally # (file is moved) repo.rollback() # but since changelog isn't under the filecache control anymore, we don't # see that it changed, and return the old changelog without reconstructing # it repo.commit('.') def setbeforeget(repo): os.remove('x') os.remove('y') repo.cached = 'string set externally' repo.invalidate() print "* neither file exists" print repo.cached repo.invalidate() f = open('x', 'w') f.write('a') f.close() print "* file x created" print repo.cached repo.cached = 'string 2 set externally' repo.invalidate() print "* string set externally again" print repo.cached repo.invalidate() f = open('y', 'w') f.write('b') f.close() print "* file y created" print repo.cached print 'basic:' print basic(fakerepo()) print print 'fakeuncacheable:' print fakeuncacheable() test_filecache_synced() print print 'setbeforeget:' print setbeforeget(fakerepo())