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From: Patrick Steinhardt <ps@pks.im>
To: git@vger.kernel.org
Subject: [PATCH 03/13] reftable/reader: unify indexed and linear seeking
Date: Wed, 8 May 2024 13:03:47 +0200	[thread overview]
Message-ID: <716863a580f9e1ef8ea796c25c97e50c63585a7b.1715166175.git.ps@pks.im> (raw)
In-Reply-To: <cover.1715166175.git.ps@pks.im>

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In `reader_seek_internal()` we either end up doing an indexed seek when
there is one or a linear seek otherwise. These two code paths are
disjunct without a good reason, where the indexed seek will cause us to
exit early.

Refactor the two code paths such that it becomes possible to share a bit
more code between them.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 reftable/reader.c | 42 ++++++++++++++++--------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/reftable/reader.c b/reftable/reader.c
index 6bfadcad71..cf7f126d8d 100644
--- a/reftable/reader.c
+++ b/reftable/reader.c
@@ -425,7 +425,7 @@ static int reader_seek_linear(struct table_iter *ti,
 	struct strbuf want_key = STRBUF_INIT;
 	struct strbuf got_key = STRBUF_INIT;
 	struct reftable_record rec;
-	int err = -1;
+	int err;
 
 	reftable_record_init(&rec, reftable_record_type(want));
 	reftable_record_key(want, &want_key);
@@ -499,8 +499,8 @@ static int reader_seek_linear(struct table_iter *ti,
 	return err;
 }
 
-static int reader_seek_indexed(struct reftable_reader *r,
-			       struct reftable_iterator *it,
+static int reader_seek_indexed(struct table_iter *ti,
+			       struct reftable_reader *r,
 			       struct reftable_record *rec)
 {
 	struct reftable_record want_index = {
@@ -510,13 +510,9 @@ static int reader_seek_indexed(struct reftable_reader *r,
 		.type = BLOCK_TYPE_INDEX,
 		.u.idx = { .last_key = STRBUF_INIT },
 	};
-	struct table_iter ti = TABLE_ITER_INIT, *malloced;
-	int err = 0;
+	int err;
 
 	reftable_record_key(rec, &want_index.u.idx.last_key);
-	err = reader_start(r, &ti, reftable_record_type(rec), 1);
-	if (err < 0)
-		goto done;
 
 	/*
 	 * The index may consist of multiple levels, where each level may have
@@ -524,7 +520,7 @@ static int reader_seek_indexed(struct reftable_reader *r,
 	 * highest layer that identifies the relevant index block as well as
 	 * the record inside that block that corresponds to our wanted key.
 	 */
-	err = reader_seek_linear(&ti, &want_index);
+	err = reader_seek_linear(ti, &want_index);
 	if (err < 0)
 		goto done;
 
@@ -550,36 +546,30 @@ static int reader_seek_indexed(struct reftable_reader *r,
 		 * all levels of the index only to find out that the key does
 		 * not exist.
 		 */
-		err = table_iter_next(&ti, &index_result);
+		err = table_iter_next(ti, &index_result);
 		if (err != 0)
 			goto done;
 
-		err = reader_table_iter_at(r, &ti, index_result.u.idx.offset, 0);
+		err = reader_table_iter_at(r, ti, index_result.u.idx.offset, 0);
 		if (err != 0)
 			goto done;
 
-		err = block_iter_seek_key(&ti.bi, &ti.br, &want_index.u.idx.last_key);
+		err = block_iter_seek_key(&ti->bi, &ti->br, &want_index.u.idx.last_key);
 		if (err < 0)
 			goto done;
 
-		if (ti.typ == reftable_record_type(rec)) {
+		if (ti->typ == reftable_record_type(rec)) {
 			err = 0;
 			break;
 		}
 
-		if (ti.typ != BLOCK_TYPE_INDEX) {
+		if (ti->typ != BLOCK_TYPE_INDEX) {
 			err = REFTABLE_FORMAT_ERROR;
 			goto done;
 		}
 	}
 
-	REFTABLE_ALLOC_ARRAY(malloced, 1);
-	*malloced = ti;
-	iterator_from_table_iter(it, malloced);
-
 done:
-	if (err)
-		table_iter_close(&ti);
 	reftable_record_release(&want_index);
 	reftable_record_release(&index_result);
 	return err;
@@ -595,15 +585,15 @@ static int reader_seek_internal(struct reftable_reader *r,
 	struct table_iter ti = TABLE_ITER_INIT, *p;
 	int err;
 
-	if (idx > 0)
-		return reader_seek_indexed(r, it, rec);
-
-	err = reader_start(r, &ti, reftable_record_type(rec), 0);
+	err = reader_start(r, &ti, reftable_record_type(rec), !!idx);
 	if (err < 0)
 		goto out;
 
-	err = reader_seek_linear(&ti, rec);
-	if (err < 0)
+	if (idx)
+		err = reader_seek_indexed(&ti, r, rec);
+	else
+		err = reader_seek_linear(&ti, rec);
+	if (err)
 		goto out;
 
 	REFTABLE_ALLOC_ARRAY(p, 1);
-- 
2.45.0


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  parent reply	other threads:[~2024-05-08 11:03 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-08 11:03 [PATCH 00/13] reftable: prepare for re-seekable iterators Patrick Steinhardt
2024-05-08 11:03 ` [PATCH 01/13] reftable/block: use `size_t` to track restart point index Patrick Steinhardt
2024-05-08 11:03 ` [PATCH 02/13] reftable/reader: avoid copying index iterator Patrick Steinhardt
2024-05-08 11:03 ` Patrick Steinhardt [this message]
2024-05-08 11:03 ` [PATCH 04/13] reftable/reader: separate concerns of table iter and reftable reader Patrick Steinhardt
2024-05-08 11:03 ` [PATCH 05/13] reftable/reader: inline `reader_seek_internal()` Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 06/13] reftable/reader: set up the reader when initializing table iterator Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 07/13] reftable/merged: split up initialization and seeking of records Patrick Steinhardt
2024-05-10 19:18   ` Justin Tobler
2024-05-13  8:36     ` Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 08/13] reftable/merged: simplify indices for subiterators Patrick Steinhardt
2024-05-10 19:25   ` Justin Tobler
2024-05-13  8:36     ` Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 09/13] reftable/generic: move seeking of records into the iterator Patrick Steinhardt
2024-05-10 21:44   ` Justin Tobler
2024-05-13  8:36     ` Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 10/13] reftable/generic: adapt interface to allow reuse of iterators Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 11/13] reftable/reader: " Patrick Steinhardt
2024-05-10 21:48   ` Justin Tobler
2024-05-13  8:36     ` Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 12/13] reftable/stack: provide convenience functions to create iterators Patrick Steinhardt
2024-05-08 11:04 ` [PATCH 13/13] reftable/merged: adapt interface to allow reuse of iterators Patrick Steinhardt
2024-05-08 23:42 ` [PATCH 00/13] reftable: prepare for re-seekable iterators Junio C Hamano
2024-05-09  0:16   ` Junio C Hamano
2024-05-10  7:48   ` Patrick Steinhardt
2024-05-10 15:40     ` Junio C Hamano
2024-05-10 16:13       ` Patrick Steinhardt
2024-05-10 17:17         ` Junio C Hamano
2024-05-13  8:46 ` [PATCH v2 " Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 01/13] reftable/block: use `size_t` to track restart point index Patrick Steinhardt
2024-05-21 13:34     ` Karthik Nayak
2024-05-22  7:23       ` Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 02/13] reftable/reader: avoid copying index iterator Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 03/13] reftable/reader: unify indexed and linear seeking Patrick Steinhardt
2024-05-21 14:41     ` Karthik Nayak
2024-05-22  7:23       ` Patrick Steinhardt
2024-05-22  7:56         ` Karthik Nayak
2024-05-13  8:47   ` [PATCH v2 04/13] reftable/reader: separate concerns of table iter and reftable reader Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 05/13] reftable/reader: inline `reader_seek_internal()` Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 06/13] reftable/reader: set up the reader when initializing table iterator Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 07/13] reftable/merged: split up initialization and seeking of records Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 08/13] reftable/merged: simplify indices for subiterators Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 09/13] reftable/generic: move seeking of records into the iterator Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 10/13] reftable/generic: adapt interface to allow reuse of iterators Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 11/13] reftable/reader: " Patrick Steinhardt
2024-05-13  8:47   ` [PATCH v2 12/13] reftable/stack: provide convenience functions to create iterators Patrick Steinhardt
2024-05-13  8:48   ` [PATCH v2 13/13] reftable/merged: adapt interface to allow reuse of iterators Patrick Steinhardt
2024-05-15 20:15   ` [PATCH v2 00/13] reftable: prepare for re-seekable iterators Justin Tobler
2024-05-21 15:31   ` Karthik Nayak
2024-05-22  7:23     ` Patrick Steinhardt

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