reftable/stack: reuse buffers when reloading stack

In `reftable_stack_reload_once()` we iterate over all the tables added
to the stack in order to figure out whether any of the tables needs to
be reloaded. We use a set of buffers in this context to compute the
paths of these tables, but discard those buffers on every iteration.
This is quite wasteful given that we do not need to transfer ownership
of the allocated buffer outside of the loop.

Refactor the code to instead reuse the buffers to reduce the number of
allocations we need to do. Note that we do not have to manually reset
the buffer because `stack_filename()` does this for us already.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Patrick Steinhardt 2023-12-11 10:07:50 +01:00 committed by Junio C Hamano
parent 5c086453ff
commit d779996a10

View file

@ -204,6 +204,7 @@ static int reftable_stack_reload_once(struct reftable_stack *st, char **names,
reftable_calloc(sizeof(struct reftable_table) * names_len);
int new_readers_len = 0;
struct reftable_merged_table *new_merged = NULL;
struct strbuf table_path = STRBUF_INIT;
int i;
while (*names) {
@ -223,13 +224,10 @@ static int reftable_stack_reload_once(struct reftable_stack *st, char **names,
if (!rd) {
struct reftable_block_source src = { NULL };
struct strbuf table_path = STRBUF_INIT;
stack_filename(&table_path, st, name);
err = reftable_block_source_from_file(&src,
table_path.buf);
strbuf_release(&table_path);
if (err < 0)
goto done;
@ -267,16 +265,13 @@ static int reftable_stack_reload_once(struct reftable_stack *st, char **names,
for (i = 0; i < cur_len; i++) {
if (cur[i]) {
const char *name = reader_name(cur[i]);
struct strbuf filename = STRBUF_INIT;
stack_filename(&filename, st, name);
stack_filename(&table_path, st, name);
reader_close(cur[i]);
reftable_reader_free(cur[i]);
/* On Windows, can only unlink after closing. */
unlink(filename.buf);
strbuf_release(&filename);
unlink(table_path.buf);
}
}
@ -288,6 +283,7 @@ static int reftable_stack_reload_once(struct reftable_stack *st, char **names,
reftable_free(new_readers);
reftable_free(new_tables);
reftable_free(cur);
strbuf_release(&table_path);
return err;
}