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reftable/block: reuse buffer to compute record keys 

When iterating over entries in the block iterator we compute the key of
each of the entries and write it into a buffer. We do not reuse the
buffer though and thus re-allocate it on every iteration, which is
wasteful.

Refactor the code to reuse the buffer.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
maint
Patrick Steinhardt 2023-12-11 10:08:12 +01:00 committed by Junio C Hamano
parent a8305bc6d8
commit c0cadb0576
2 changed files with 10 additions and 11 deletions
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19
reftable/block.c
View File

@ -323,30 +323,28 @@ int block_iter_next(struct block_iter *it, struct reftable_record *rec)
.len = it->br->block_len - it->next_off, .len = it->br->block_len - it->next_off,
}; };
struct string_view start = in; struct string_view start = in;
struct strbuf key = STRBUF_INIT;
uint8_t extra = 0; uint8_t extra = 0;
int n = 0; int n = 0;


if (it->next_off >= it->br->block_len) if (it->next_off >= it->br->block_len)
return 1; return 1;


n = reftable_decode_key(&key, &extra, it->last_key, in); n = reftable_decode_key(&it->key, &extra, it->last_key, in);
if (n < 0) if (n < 0)
return -1; return -1;


if (!key.len) if (!it->key.len)
return REFTABLE_FORMAT_ERROR; return REFTABLE_FORMAT_ERROR;


string_view_consume(&in, n); string_view_consume(&in, n);
n = reftable_record_decode(rec, key, extra, in, it->br->hash_size); n = reftable_record_decode(rec, it->key, extra, in, it->br->hash_size);
if (n < 0) if (n < 0)
return -1; return -1;
string_view_consume(&in, n); string_view_consume(&in, n);


strbuf_reset(&it->last_key); strbuf_reset(&it->last_key);
strbuf_addbuf(&it->last_key, &key); strbuf_addbuf(&it->last_key, &it->key);
it->next_off += start.len - in.len; it->next_off += start.len - in.len;
strbuf_release(&key);
return 0; return 0;
} }


@ -377,6 +375,7 @@ int block_iter_seek(struct block_iter *it, struct strbuf *want)
void block_iter_close(struct block_iter *it) void block_iter_close(struct block_iter *it)
{ {
strbuf_release(&it->last_key); strbuf_release(&it->last_key);
strbuf_release(&it->key);
} }


int block_reader_seek(struct block_reader *br, struct block_iter *it, int block_reader_seek(struct block_reader *br, struct block_iter *it,
@ -387,7 +386,6 @@ int block_reader_seek(struct block_reader *br, struct block_iter *it,
.r = br, .r = br,
}; };
struct reftable_record rec = reftable_new_record(block_reader_type(br)); struct reftable_record rec = reftable_new_record(block_reader_type(br));
struct strbuf key = STRBUF_INIT;
int err = 0; int err = 0;
struct block_iter next = BLOCK_ITER_INIT; struct block_iter next = BLOCK_ITER_INIT;


@ -414,8 +412,8 @@ int block_reader_seek(struct block_reader *br, struct block_iter *it,
if (err < 0) if (err < 0)
goto done; goto done;


reftable_record_key(&rec, &key); reftable_record_key(&rec, &it->key);
if (err > 0 || strbuf_cmp(&key, want) >= 0) { if (err > 0 || strbuf_cmp(&it->key, want) >= 0) {
err = 0; err = 0;
goto done; goto done;
} }
@ -424,8 +422,7 @@ int block_reader_seek(struct block_reader *br, struct block_iter *it,
} }


done: done:
strbuf_release(&key); block_iter_close(&next);
strbuf_release(&next.last_key);
reftable_record_release(&rec); reftable_record_release(&rec);


return err; return err;

2
reftable/block.h
View File

@ -84,10 +84,12 @@ struct block_iter {


/* key for last entry we read. */ /* key for last entry we read. */
struct strbuf last_key; struct strbuf last_key;
struct strbuf key;
}; };


#define BLOCK_ITER_INIT { \ #define BLOCK_ITER_INIT { \
.last_key = STRBUF_INIT, \ .last_key = STRBUF_INIT, \
.key = STRBUF_INIT, \
} }


/* initializes a block reader. */ /* initializes a block reader. */