match: optimize visitdir() for patterns matching only root directory
Because _rootsanddirs() returns a list of directories to visit
recursively and a list of directories to visit non-recursively. For
patterns such as 'rootfilesin:foo/bar', we clearly need to visit the
directory foo/bar, but we also need to visit its parents. The method
therefore uses util.dirs() to find the parent directories of
'foo/bar'. That method does not include the root directory, but since
we obviously need to visit the root directory, we always added '.' to
the set of directories to visit non-recursively.
The visitdir() method had special handling to consider set(['.']) to
mean that no includes had been specified and would thus visit all
directories. However, when the pattern is 'rootfilesin:.', set(['.'])
is actually the real set of directories to visit and the special
handling of that set meant that all directories got visited instead of
just the root directory.
The fix is simple: add '.' to the set of parent directories in
_rootsanddirs() and stop treating set(['.']) specially. This makes
hg files -r . -I rootfilesin:.
in a treemanifest version of the Firefox repo go from 1.5s to 0.26s on
warm disk (and a *much* bigger improvement on cold disk).
Note that the -I is necessary for no good reason. We just haven't
optimized visitdir() for regular (non-include, non-exclude) patterns
yet.
Test how largefiles abort in case the disk runs full
$ cat > criple.py <<EOF
> import os, errno, shutil
> from mercurial import util
> #
> # this makes the original largefiles code abort:
> _origcopyfileobj = shutil.copyfileobj
> def copyfileobj(fsrc, fdst, length=16*1024):
> # allow journal files (used by transaction) to be written
> if 'journal.' in fdst.name:
> return _origcopyfileobj(fsrc, fdst, length)
> fdst.write(fsrc.read(4))
> raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
> shutil.copyfileobj = copyfileobj
> #
> # this makes the rewritten code abort:
> def filechunkiter(f, size=131072, limit=None):
> yield f.read(4)
> raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
> util.filechunkiter = filechunkiter
> #
> def oslink(src, dest):
> raise OSError("no hardlinks, try copying instead")
> util.oslink = oslink
> EOF
$ echo "[extensions]" >> $HGRCPATH
$ echo "largefiles =" >> $HGRCPATH
$ hg init alice
$ cd alice
$ echo "this is a very big file" > big
$ hg add --large big
$ hg commit --config extensions.criple=$TESTTMP/criple.py -m big
abort: No space left on device
[255]
The largefile is not created in .hg/largefiles:
$ ls .hg/largefiles
dirstate
The user cache is not even created:
>>> import os; os.path.exists("$HOME/.cache/largefiles/")
False
Make the commit with space on the device:
$ hg commit -m big
Now make a clone with a full disk, and make sure lfutil.link function
makes copies instead of hardlinks:
$ cd ..
$ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
updating to branch default
getting changed largefiles
abort: No space left on device
[255]
The largefile is not created in .hg/largefiles:
$ ls bob/.hg/largefiles
dirstate