From: "Thomas Rast" <trast@xxxxxxxxxxx> Sent: Monday, February 20, 2012 8:29
AM
"Philip Oakley" <philipoakley@xxxxxxx> writes:
If I have a renamed file which is a git object, such a "Git_Object", was
8c-something-or-other, what is the easiest way of examining / decoding /
recreating the original file (either as its sha1, or a cat-file).
I don't appear to be able to unzip the file in its raw format... I'm
using
Msysgit on windows XP.
Correction to reply to xu's message: and I have /NOT/ located an
unzip programme that will take the plain git object and decode it.
The SHA1 is over the decompressed object contents. The file simply
holds a zlib-compressed stream of those contents. (It's pretty much
like gzip without the file header.)
You can use any bindings to zlib and something that does sha1, e.g. in
python:
$ cd g/.git/objects/aa/ # my git.git
$ ls
592bda986a8380b64acd8cbb3d5bdfcbc0834d
6322a757bee31919f54edcc127608a3d724c99
$ python
Python 2.7.2 (default, Aug 19 2011, 20:41:43) [GCC] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import hashlib
>>>
hashlib.sha1(open('592bda986a8380b64acd8cbb3d5bdfcbc0834d').read().decode('zlib')).digest().encode('hex')
'aa592bda986a8380b64acd8cbb3d5bdfcbc0834d'
Notice that the first byte of the hash goes into the directory name.
At the moment I'm in a Catch 22 situation where I can't make the first step
of examining the deflated contents, so I can't do all those next steps to
get the sha1 etc.. Have I misunderstood your suggestions?
Philip
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