On Thu, 2010-07-22 at 17:25 -0400, James Antill wrote:
>
> class RPMDBAdditionalDataPackage(object):
> +
> + # We do auto hardlink on these attributes
> + _auto_hardlink_attrs = set(['from_repo', 'releasever', 'checksum_type',
> + 'installed_by', 'changed_by', 'reason'])
> +
> def __init__(self, conf, pkgdir, yumdb_cache=None):
> self._conf = conf
> self._mydir = pkgdir
> @@ -1497,6 +1502,41 @@ class RPMDBAdditionalDataPackage(object):
> # so we make it generic.
> self._yumdb_cache = yumdb_cache
>
> + def _auto_yumdb_cache(self, attr, value, fn, nlinks=1):
> + """ Create a cache for writting yumdb data out, to use link()
> instead of
> + open()+write(). hardlink -c works better, but this is "free" and
> + automatic. """
> + if self._yumdb_cache is None:
> + return
> + if nlinks <= 1 and attr not in self._auto_hardlink_attrs:
> + return
> +
> + if attr not in self._yumdb_cache:
> + self._yumdb_cache[attr] = {}
> + if value in self._yumdb_cache[attr]:
> + if self._yumdb_cache[attr][value][0] >= nlinks:
> + # We already have a better cache file.
> + return
> +
> + self._yumdb_cache[attr][value] = (nlinks, fn)
> +
> + def _auto_link_yumdb_cache(self, attr, value, fn):
> + """ If we have a matching yumdb cache, link() to it instead of having
> + to open()+write(). """
> + if self._yumdb_cache is None:
> + return False
> + if attr not in self._yumdb_cache:
> + return False
> + if value not in self._yumdb_cache[attr]:
> + return False
> +
> + misc.unlink_f(fn + '.tmp')
> + os.link(self._yumdb_cache[attr][value][1], fn + '.tmp')
> + os.rename(fn + '.tmp', fn)
> + self._read_cached_data[attr] = value
> +
> + return True
> +
Seems like we would want to wrap the above in a try/except to catch
random FS or other misc errors and do the normal write if it fails.
You do treat it as a fast-path but a try/except would make it 'safer'
and that'll protect us if anyone is doing something especially stupid
with weird filesystems.
-sv
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