Append/prepend commands. Introduce new storage commands "append" and "prepend" for atomic value modification. They follow generic storage commands interface as described in doc/protocol.txt: <command name> <key> <flags> <exptime> <bytes>\r\n <data block>\r\n Current implementation involves memcpy() twice to combine values on writing (i.e. full resulting value are copied), but truly atomic (and even threadsafe).

Anatoly Vorobey <mellon@pobox.com>
Brad Fitzpatrick <brad@danga.com>