On 04/18/2012 03:45 PM, Greg Stein wrote:
> On Wed, Apr 18, 2012 at 18:42, Blair Zajac<blair_at_orcaware.com> wrote:
>> On 04/18/2012 03:35 PM, Greg Stein wrote:
>>> On Wed, Apr 18, 2012 at 18:11,<blair_at_apache.org> wrote:
>>>>
>>>> Author: blair
>>>> Date: Wed Apr 18 22:11:43 2012
>>>> New Revision: 1327703
>>>>
>>>> URL: http://svn.apache.org/viewvc?rev=1327703&view=rev
>>>> Log:
>>>> Add and use svn_checksum__from_digest_sha1().
>>>>
>>>> This replaces svn_checksum__from_digest() taking a svn_checksum_sha1
>>>> argument with a new svn_checksum_t constructor function.
>>>>
>>>> * subversion/include/private/svn_subr_private.h,
>>>> * subversion/libsvn_subr/checksum.c
>>>> (svn_checksum__from_digest_sha1):
>>>> New private function.
>>>>
>>>> * subversion/libsvn_fs_base/util/fs_skels.c
>>>> (svn_fs_base__parse_representation_skel):
>>>> Replace
>>>> svn_checksum__from_digest(digest, svn_checksum_sha1, pool);
>>>> with
>>>> svn_checksum__from_digest_sha1(digest, pool);
>>>
>>>
>>> Shouldn't we be using svn_checksum_serialize() and _deserialize()
>>> rather than raw digests?
>>>
>>> (iow, we "shouldn't" need from_digest_sha1)
>>
>>
>> They don't contain the same bytes. I wasn't aware of
>> svn_checksum_serialize() till now, but those prepend a checksum type string
>> to the hex representation, as these are raw digest bytes.
>>
>> This work was to get rid of svn_checksum__from_digest(), which is now almost
>> complete, per the other thread.
>
> Yup, I understood. Sorry that I wasn't clear: I meant in our
> serialization code, shouldn't we use the "proper" functions rather
> than raw sha1 digests? Is there any way to switch to them at a
> higher/semantic level?
>
> I haven't looked at that stuff, but I'm going to guess repositories
> now exist with raw sha1 digests. Is there a format type in there? Can
> we start writing "csum" and svn_checksum_serialize() into the skel?
> And then read raw md5, raw sha1, or a serialized checksum?
I'm not familiar with this part of the code either (not having looked at
the svn_skel.h before) but that make sense. The code could look for a
raw digest or a $name$ and then use that.
It doesn't look like it would be too hard. Because the skel has a len,
if it's equal to APR_SHA1_DIGESTSIZE then you would use the raw digest,
otherwise use svn_checksum_deserialize().
Sounds like a 1.8 repository upgrade though, since once you wrote a
$sha1$ style string, older Subversion's wouldn't parse it directly.
I won't be taking this on, I've still got a memory lifetime issue I'm
debugging and then a svn commit thread pool to write to support 4
commits/sec from remote clients that are consuming all threads from our
RPC thread pool and killing readers.
Blair
Received on 2012-04-19 01:16:02 CEST