The `index_blob_packfile_transaction()` function handles streaming a
blob from an fd to compute its object ID and conditionally writes the
object directly to a packfile if the INDEX_WRITE_OBJECT flag is set. A
subsequent commit will make these packfile object writes part of the
transaction interface. Consequently, having the object write be
conditional on this flag is a bit awkward.
In preparation for this change, introduce a dedicated
`hash_blob_stream()` helper that only computes the OID from a `struct
odb_write_stream`. This is invoked by `index_fd()` instead when the
INDEX_WRITE_OBJECT is not set. The object write performed via
`index_blob_packfile_transaction()` is made unconditional accordingly.
Signed-off-by: Justin Tobler <jltobler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `read()` callback used by `struct odb_write_stream` currently
returns a pointer to an internal buffer along with the number of bytes
read. This makes buffer ownership unclear and provides no way to report
errors.
Update the interface to instead require the caller to provide a buffer,
and have the callback return the number of bytes written to it or a
negative value on error. While at it, also move the `struct
odb_write_stream` definition to "odb/streaming.h". Call sites are
updated accordingly.
Signed-off-by: Justin Tobler <jltobler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The odb_read_stream structure uses unsigned long for the size field,
which is 32-bit on Windows even in 64-bit builds. When streaming
objects larger than 4GB, the size would be truncated to zero or an
incorrect value, resulting in empty files being written to disk.
Change the size field in odb_read_stream to size_t and introduce
unpack_object_header_sz() to return sizes via size_t pointer. Since
object_info.sizep remains unsigned long for API compatibility, use
temporary variables where the types differ, with comments noting the
truncation limitation for code paths that still use unsigned long.
Widening the producers to size_t in this way introduces a handful of
silent size_t -> unsigned long narrowings on Windows, all in
builtin/pack-objects.c, where the consumers are still typed
unsigned long. Make those narrowings explicit with
cast_size_t_to_ulong() so they assert loudly the moment an object
actually exceeds ULONG_MAX bytes:
- oe_get_size_slow() returns unsigned long but holds a size_t
locally; cast at the return.
- write_reuse_object() passes a size_t into check_pack_inflate(),
whose expect parameter is unsigned long; cast at the call.
- check_object() routes a size_t through SET_SIZE() and
SET_DELTA_SIZE(), both of which take unsigned long via
oe_set_size() / oe_set_delta_size(); cast at the three call
sites in the OBJ_OFS_DELTA / OBJ_REF_DELTA branches and in the
non-delta default arm.
The cast-only treatment is deliberately a stop-gap. Properly
widening oe_set_size, oe_get_size_slow's return type,
check_pack_inflate's expect parameter, object_info.sizep,
patch_delta, and the OE_SIZE_BITS bit-fields cascades into a series
that is too large to be reviewable, so the proper widening is
deferred to a follow-up topic. Until then,
cast_size_t_to_ulong() at least makes the truncation explicit at
the source: it documents the boundary, and on a 64-bit non-Windows
platform it is a no-op.
This was originally authored by LordKiRon <https://github.com/LordKiRon>,
who preferred not to reveal their real name and therefore agreed that I
take over authorship.
Helped-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the preceding commits we have turned `struct odb_read_stream` into a
publicly visible structure. Furthermore, this structure now contains the
type and size of the object that we are about to stream. Consequently,
the out-pointers that we used before to propagate the type and size of
the streamed object are now somewhat redundant with the data contained
in the structure itself.
Drop these out-pointers and adapt callers accordingly.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "streaming" terminology is somewhat generic, so it may not be
immediately obvious that "streaming.{c,h}" is specific to the object
database. Rectify this by moving it into the "odb/" directory so that it
can be immediately attributed to the object subsystem.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
