Re: [PATCH 2/5] pack-bitmap: tag bitmapped packs with their corresponding MIDX
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Aug 28, 2024, 00:14 UTC
- Message-ID
- <xmqqplpt5wrt.fsf@gitster.g>
- In-Reply-To
- <1838bbcf7fe6daa58a7db78b81a2d08138fe176e.1724793201.git.me@ttaylorr.com>
Taylor Blau <me@ttaylorr.com> writes:
Show 28 quoted lines
> The next commit will need to use the bitmap's MIDX (if one exists) to > translate bit positions into pack-relative positions in the source pack. > > Ordinarily, we'd use the "midx" field of the bitmap_index struct. But > since that struct is defined within pack-bitmap.c, and our caller is in > a separate compilation unit, we do not have access to the MIDX field. > > Instead, add a "from_midx" field to the bitmapped_pack structure so that > we can use that piece of data from outside of pack-bitmap.c. The caller > that uses this new piece of information will be added in the following > commit. > > Signed-off-by: Taylor Blau <me@ttaylorr.com> > --- > midx.c | 1 + > pack-bitmap.c | 1 + > pack-bitmap.h | 1 + > 3 files changed, 3 insertions(+) > > diff --git a/midx.c b/midx.c > index ca98bfd7c6..67e0d64004 100644 > --- a/midx.c > +++ b/midx.c > @@ -496,6 +496,7 @@ int nth_bitmapped_pack(struct repository *r, struct multi_pack_index *m, > MIDX_CHUNK_BITMAPPED_PACKS_WIDTH * local_pack_int_id + > sizeof(uint32_t)); > bp->pack_int_id = pack_int_id; > + bp->from_midx = m;
Do multi_pack_index objects live as long as bitmapped_pack objects that point at them live? If m later goes away without letting the bitmapped_pack know about it, the borrowed pointer in from_midx would become dangling, which is not what we want to see.
"None of these objects are released or relocated while we are running pack-objects, so once the .from_midx member is assigned here, it will always be pointing at a valid multi_pack_index object" is a satisfactory answer, I guess.