We're about to enable `-Wwrite-strings`, which changes the type of
string constants to `const char[]`. Fix various sites where we assign
such constants to non-const variables.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When doing the binary search over restart points in a block we need to
decode the record keys. This decoding step can result in an error when
the block is corrupted, which we indicate to the caller of the binary
search by setting `args.error = 1`. But the only caller that exists
mishandles this because it in fact performs the error check before
calling `binsearch()`.
Fix this bug by checking for errors at the right point in time.
Furthermore, refactor `binsearch()` so that it aborts the search in case
the callback function returns a negative value so that we don't
needlessly continue to search the block.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `binsearch()` function can be used to find the first element for
which a callback functions returns a truish value. But while the array
size is of type `size_t`, the function in fact returns an `int` that is
supposed to index into that array.
Fix the function signature to return a `size_t`. This conversion does
not change any semantics given that the function would only ever return
a value in the range `[0, sz]` anyway.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While the stack length is already stored as `size_t`, we frequently use
`int`s to refer to those stacks throughout the reftable library. Convert
those cases to use `size_t` instead to make things consistent.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Throughout the reftable library we have many cases where we need to grow
arrays. In order to avoid too many reallocations, we roughly double the
capacity of the array on each iteration. The resulting code pattern is
duplicated across many sites.
We have similar patterns in our main codebase, which is why we have
eventually introduced an `ALLOC_GROW()` macro to abstract it away and
avoid some code duplication. We cannot easily reuse this macro here
though because `ALLOC_GROW()` uses `REALLOC_ARRAY()`, which in turn will
call realloc(3P) to grow the array. The reftable code is structured as a
library though (even if the boundaries are fuzzy), and one property this
brings with it is that it is possible to plug in your own allocators. So
instead of using realloc(3P), we need to use `reftable_realloc()` that
knows to use the user-provided implementation.
So let's introduce two new macros `REFTABLE_REALLOC_ARRAY()` and
`REFTABLE_ALLOC_GROW()` that mirror what we do in our main codebase,
with two modifications:
- They use `reftable_realloc()`, as explained above.
- They use a different growth factor of `2 * cap + 1` instead of `(cap
+ 16) * 3 / 2`.
The second change is because we know a bit more about the allocation
patterns in the reftable library. In most cases, we end up only having a
handful of items in the array and don't end up growing them. The initial
capacity that our normal growth factor uses (which is 24) would thus end
up over-allocating in a lot of code paths. This effect is measurable:
- Before change:
HEAP SUMMARY:
in use at exit: 671,983 bytes in 152 blocks
total heap usage: 3,843,446 allocs, 3,843,294 frees, 223,761,402 bytes allocated
- After change with a growth factor of `(2 * alloc + 1)`:
HEAP SUMMARY:
in use at exit: 671,983 bytes in 152 blocks
total heap usage: 3,843,446 allocs, 3,843,294 frees, 223,761,410 bytes allocated
- After change with a growth factor of `(alloc + 16)* 2 / 3`:
HEAP SUMMARY:
in use at exit: 671,983 bytes in 152 blocks
total heap usage: 3,833,673 allocs, 3,833,521 frees, 4,728,251,742 bytes allocated
While the total heap usage is roughly the same, we do end up allocating
significantly more bytes with our usual growth factor (in fact, roughly
21 times as many).
Convert the reftable library to use these new macros.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit provides basic utility classes for the reftable library.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
