Re: [PATCH 6/7] reftable/record: use scratch buffer when decoding records

> When decoding log records we need a temporary buffer to decode the
> reflog entry's name, mail address and message. As this buffer is local
> to the function we thus have to reallocate it for every single log
> record which we're about to decode, which is inefficient.
> 
> Refactor the code such that callers need to pass in a scratch buffer,
> which allows us to reuse it for multiple decodes. This reduces the
> number of allocations when iterating through reflogs. Before:
> 
>     HEAP SUMMARY:
>         in use at exit: 13,473 bytes in 122 blocks
>       total heap usage: 2,068,487 allocs, 2,068,365 frees, 305,122,946 bytes allocated
> 
> After:
> 
>     HEAP SUMMARY:
>         in use at exit: 13,473 bytes in 122 blocks
>       total heap usage: 1,068,485 allocs, 1,068,363 frees, 281,122,886 bytes allocated
> 
> Note that this commit also drop some redundant calls to `strbuf_reset()`
> right before calling `decode_string()`. The latter already knows to
> reset the buffer, so there is no need for these.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  reftable/block.c       |  4 ++-
>  reftable/block.h       |  2 ++
>  reftable/record.c      | 52 ++++++++++++++++++--------------------
>  reftable/record.h      |  5 ++--
>  reftable/record_test.c | 57 ++++++++++++++++++++++++++----------------
>  5 files changed, 68 insertions(+), 52 deletions(-)