pointer where to store the read object
database to search for the object in.
a prefix of the id of the object to read.
the length of the prefix
0 if the object was read, GIT_ENOTFOUND if the object is not in the database. GIT_EAMBIGUOUS if the prefix is ambiguous(several objects match the prefix)
Read an object from the database, given a prefix of its identifier.
This method queries all available ODB backends trying to match the 'len' first hexadecimal characters of the 'short_id'. The remaining (GIT_OID_SHA1_HEXSIZE-len)*4 bits of 'short_id' must be 0s. 'len' must be at least GIT_OID_MINPREFIXLEN, and the prefix must be long enough to identify a unique object in all the backends; the method will fail otherwise.
The returned object is reference counted and internally cached, so it should be closed by the user once it's no longer in use.