In anticipation of combining the logic from the commit-graph and
multi-pack-index file formats, create a new chunk-format API. Use a
'struct chunkfile' pointer to keep track of data that has been
registered for writes. This struct is anonymous outside of
chunk-format.c to ensure no user attempts to interfere with the data.
The next change will use this API in commit-graph.c, but the general
approach is:
1. initialize the chunkfile with init_chunkfile(f).
2. add chunks in the intended writing order with add_chunk().
3. write any header information to the hashfile f.
4. write the chunkfile data using write_chunkfile().
5. free the chunkfile struct using free_chunkfile().
Helped-by: Taylor Blau <me@ttaylorr.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee