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Mon, 31 Mar 2025 04:41:30 -0400 (EDT) Received: by vm-mail (OpenSMTPD) with ESMTPSA id c5c83ce6 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Mon, 31 Mar 2025 08:41:30 +0000 (UTC) From: Patrick Steinhardt Date: Mon, 31 Mar 2025 10:41:28 +0200 Subject: [PATCH 10/16] reftable/block: store block pointer in the block iterator Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250331-pks-reftable-polishing-v1-10-ebed5247434c@pks.im> References: <20250331-pks-reftable-polishing-v1-0-ebed5247434c@pks.im> In-Reply-To: <20250331-pks-reftable-polishing-v1-0-ebed5247434c@pks.im> To: git@vger.kernel.org Cc: X-Mailer: b4 0.14.2 The block iterator requires access to a bunch of data from the underlying `reftable_block` that it is iterating over. This data is stored by copying over relevant data into a separate set of variables. This has multiple downsides: - We require more storage space than necessary. This is more of a theoretical issue as we shouldn't ever have many blocks. - We have to perform more bookkeeping, and the variable names are inconsistent across the two data structures. This can lead to some confusion. - The lifetime of the block iterator is tied to the block anyway, but we hide that a bit by only storing pointers into the block. There isn't really any good reason why we rip out parts of the block instead of storing a pointer to the block itself. Refactor the code to do so. Despite being simpler, it also allows us to decouple the lifetime of the block iterator from seeking in a subsequent commit. Signed-off-by: Patrick Steinhardt --- reftable/block.c | 22 ++++++++-------------- reftable/block.h | 4 +--- 2 files changed, 9 insertions(+), 17 deletions(-) diff --git a/reftable/block.c b/reftable/block.c index d188665388d..576c6caf59b 100644 --- a/reftable/block.c +++ b/reftable/block.c @@ -381,13 +381,11 @@ static uint32_t block_restart_offset(const struct reftable_block *b, size_t idx) return reftable_get_be24(b->block.data + b->restart_off + 3 * idx); } -void block_iter_seek_start(struct block_iter *it, const struct reftable_block *b) +void block_iter_seek_start(struct block_iter *it, const struct reftable_block *block) { - it->block = b->block.data; - it->block_len = b->restart_off; - it->hash_size = b->hash_size; + it->block = block; reftable_buf_reset(&it->last_key); - it->next_off = b->header_off + 4; + it->next_off = block->header_off + 4; } struct restart_needle_less_args { @@ -435,14 +433,14 @@ static int restart_needle_less(size_t idx, void *_args) int block_iter_next(struct block_iter *it, struct reftable_record *rec) { struct string_view in = { - .buf = (unsigned char *) it->block + it->next_off, - .len = it->block_len - it->next_off, + .buf = (unsigned char *) it->block->block.data + it->next_off, + .len = it->block->restart_off - it->next_off, }; struct string_view start = in; uint8_t extra = 0; int n = 0; - if (it->next_off >= it->block_len) + if (it->next_off >= it->block->restart_off) return 1; n = reftable_decode_key(&it->last_key, &extra, in); @@ -452,7 +450,7 @@ int block_iter_next(struct block_iter *it, struct reftable_record *rec) return REFTABLE_FORMAT_ERROR; string_view_consume(&in, n); - n = reftable_record_decode(rec, it->last_key, extra, in, it->hash_size, + n = reftable_record_decode(rec, it->last_key, extra, in, it->block->hash_size, &it->scratch); if (n < 0) return -1; @@ -467,8 +465,6 @@ void block_iter_reset(struct block_iter *it) reftable_buf_reset(&it->last_key); it->next_off = 0; it->block = NULL; - it->block_len = 0; - it->hash_size = 0; } void block_iter_close(struct block_iter *it) @@ -528,9 +524,7 @@ int block_iter_seek_key(struct block_iter *it, const struct reftable_block *bloc it->next_off = block_restart_offset(block, i - 1); else it->next_off = block->header_off + 4; - it->block = block->block.data; - it->block_len = block->restart_off; - it->hash_size = block->hash_size; + it->block = block; err = reftable_record_init(&rec, reftable_block_type(block)); if (err < 0) diff --git a/reftable/block.h b/reftable/block.h index 4f7f29028c4..268d5a1e005 100644 --- a/reftable/block.h +++ b/reftable/block.h @@ -67,9 +67,7 @@ void block_writer_release(struct block_writer *bw); struct block_iter { /* offset within the block of the next entry to read. */ uint32_t next_off; - const unsigned char *block; - size_t block_len; - uint32_t hash_size; + const struct reftable_block *block; /* key for last entry we read. */ struct reftable_buf last_key;