reftable/table: move reading block into block reader

The logic to read blocks from a reftable is scattered across both the
table and the block subsystems. Besides causing somewhat fuzzy
responsibilities, it also means that we have to awkwardly pass around
the ownership of blocks between the subsystems.

Refactor the code so that we stop passing the block when initializing a
reader, but instead by passing in the block source plus the offset at
which we're supposed to read a block. Like this, the ownership of the
block itself doesn't need to get handed over as the block reader is the
one owning the block right from the start.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 40 insertions, 36 deletions

diff --git a/t/unit-tests/t-reftable-block.c b/t/unit-tests/t-reftable-block.c
index 8bb4048234..dbec6a5d0d 100644
--- a/t/unit-tests/t-reftable-block.c
+++ b/t/unit-tests/t-reftable-block.c
@@ -19,7 +19,7 @@ static void t_ref_block_read_write(void)
 	struct reftable_record recs[30];
 	const size_t N = ARRAY_SIZE(recs);
 	const size_t block_size = 1024;
-	struct reftable_block block = { 0 };
+	struct reftable_block_source source = { 0 };
 	struct block_writer bw = {
 		.last_key = REFTABLE_BUF_INIT,
 	};
@@ -30,13 +30,14 @@ static void t_ref_block_read_write(void)
 	int ret;
 	struct block_reader br = { 0 };
 	struct block_iter it = BLOCK_ITER_INIT;
-	struct reftable_buf want = REFTABLE_BUF_INIT, buf = REFTABLE_BUF_INIT;
+	struct reftable_buf want = REFTABLE_BUF_INIT;
+	struct reftable_buf block = REFTABLE_BUF_INIT;
 
-	REFTABLE_CALLOC_ARRAY(block.data, block_size);
-	check(block.data != NULL);
+	REFTABLE_CALLOC_ARRAY(block.buf, block_size);
+	check(block.buf != NULL);
 	block.len = block_size;
-	block_source_from_buf(&block.source ,&buf);
-	ret = block_writer_init(&bw, BLOCK_TYPE_REF, block.data, block_size,
+
+	ret = block_writer_init(&bw, BLOCK_TYPE_REF, (uint8_t *) block.buf, block_size,
 				header_off, hash_size(REFTABLE_HASH_SHA1));
 	check(!ret);
 
@@ -62,7 +63,8 @@ static void t_ref_block_read_write(void)
 
 	block_writer_release(&bw);
 
-	block_reader_init(&br, &block, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
+	block_source_from_buf(&source ,&block);
+	block_reader_init(&br, &source, 0, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
 
 	block_iter_seek_start(&it, &br);
 
@@ -100,9 +102,8 @@ static void t_ref_block_read_write(void)
 	block_reader_release(&br);
 	block_iter_close(&it);
 	reftable_record_release(&rec);
-	block_source_return_block(&br.block);
 	reftable_buf_release(&want);
-	reftable_buf_release(&buf);
+	reftable_buf_release(&block);
 	for (i = 0; i < N; i++)
 		reftable_record_release(&recs[i]);
 }
@@ -113,7 +114,7 @@ static void t_log_block_read_write(void)
 	struct reftable_record recs[30];
 	const size_t N = ARRAY_SIZE(recs);
 	const size_t block_size = 2048;
-	struct reftable_block block = { 0 };
+	struct reftable_block_source source = { 0 };
 	struct block_writer bw = {
 		.last_key = REFTABLE_BUF_INIT,
 	};
@@ -124,13 +125,14 @@ static void t_log_block_read_write(void)
 	int ret;
 	struct block_reader br = { 0 };
 	struct block_iter it = BLOCK_ITER_INIT;
-	struct reftable_buf want = REFTABLE_BUF_INIT, buf = REFTABLE_BUF_INIT;
+	struct reftable_buf want = REFTABLE_BUF_INIT;
+	struct reftable_buf block = REFTABLE_BUF_INIT;
 
-	REFTABLE_CALLOC_ARRAY(block.data, block_size);
-	check(block.data != NULL);
+	REFTABLE_CALLOC_ARRAY(block.buf, block_size);
+	check(block.buf != NULL);
 	block.len = block_size;
-	block_source_from_buf(&block.source ,&buf);
-	ret = block_writer_init(&bw, BLOCK_TYPE_LOG, block.data, block_size,
+
+	ret = block_writer_init(&bw, BLOCK_TYPE_LOG, (uint8_t *) block.buf, block_size,
 				header_off, hash_size(REFTABLE_HASH_SHA1));
 	check(!ret);
 
@@ -151,7 +153,8 @@ static void t_log_block_read_write(void)
 
 	block_writer_release(&bw);
 
-	block_reader_init(&br, &block, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
+	block_source_from_buf(&source, &block);
+	block_reader_init(&br, &source, 0, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
 
 	block_iter_seek_start(&it, &br);
 
@@ -190,9 +193,8 @@ static void t_log_block_read_write(void)
 	block_reader_release(&br);
 	block_iter_close(&it);
 	reftable_record_release(&rec);
-	block_source_return_block(&br.block);
 	reftable_buf_release(&want);
-	reftable_buf_release(&buf);
+	reftable_buf_release(&block);
 	for (i = 0; i < N; i++)
 		reftable_record_release(&recs[i]);
 }
@@ -203,7 +205,7 @@ static void t_obj_block_read_write(void)
 	struct reftable_record recs[30];
 	const size_t N = ARRAY_SIZE(recs);
 	const size_t block_size = 1024;
-	struct reftable_block block = { 0 };
+	struct reftable_block_source source = { 0 };
 	struct block_writer bw = {
 		.last_key = REFTABLE_BUF_INIT,
 	};
@@ -214,13 +216,14 @@ static void t_obj_block_read_write(void)
 	int ret;
 	struct block_reader br = { 0 };
 	struct block_iter it = BLOCK_ITER_INIT;
-	struct reftable_buf want = REFTABLE_BUF_INIT, buf = REFTABLE_BUF_INIT;
+	struct reftable_buf want = REFTABLE_BUF_INIT;
+	struct reftable_buf block = REFTABLE_BUF_INIT;
 
-	REFTABLE_CALLOC_ARRAY(block.data, block_size);
-	check(block.data != NULL);
+	REFTABLE_CALLOC_ARRAY(block.buf, block_size);
+	check(block.buf != NULL);
 	block.len = block_size;
-	block_source_from_buf(&block.source, &buf);
-	ret = block_writer_init(&bw, BLOCK_TYPE_OBJ, block.data, block_size,
+
+	ret = block_writer_init(&bw, BLOCK_TYPE_OBJ, (uint8_t *) block.buf, block_size,
 				header_off, hash_size(REFTABLE_HASH_SHA1));
 	check(!ret);
 
@@ -243,7 +246,8 @@ static void t_obj_block_read_write(void)
 
 	block_writer_release(&bw);
 
-	block_reader_init(&br, &block, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
+	block_source_from_buf(&source, &block);
+	block_reader_init(&br, &source, 0, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
 
 	block_iter_seek_start(&it, &br);
 
@@ -273,9 +277,8 @@ static void t_obj_block_read_write(void)
 	block_reader_release(&br);
 	block_iter_close(&it);
 	reftable_record_release(&rec);
-	block_source_return_block(&br.block);
 	reftable_buf_release(&want);
-	reftable_buf_release(&buf);
+	reftable_buf_release(&block);
 	for (i = 0; i < N; i++)
 		reftable_record_release(&recs[i]);
 }
@@ -286,7 +289,7 @@ static void t_index_block_read_write(void)
 	struct reftable_record recs[30];
 	const size_t N = ARRAY_SIZE(recs);
 	const size_t block_size = 1024;
-	struct reftable_block block = { 0 };
+	struct reftable_block_source source = { 0 };
 	struct block_writer bw = {
 		.last_key = REFTABLE_BUF_INIT,
 	};
@@ -298,13 +301,14 @@ static void t_index_block_read_write(void)
 	int ret;
 	struct block_reader br = { 0 };
 	struct block_iter it = BLOCK_ITER_INIT;
-	struct reftable_buf want = REFTABLE_BUF_INIT, buf = REFTABLE_BUF_INIT;
+	struct reftable_buf want = REFTABLE_BUF_INIT;
+	struct reftable_buf block = REFTABLE_BUF_INIT;
 
-	REFTABLE_CALLOC_ARRAY(block.data, block_size);
-	check(block.data != NULL);
+	REFTABLE_CALLOC_ARRAY(block.buf, block_size);
+	check(block.buf != NULL);
 	block.len = block_size;
-	block_source_from_buf(&block.source, &buf);
-	ret = block_writer_init(&bw, BLOCK_TYPE_INDEX, block.data, block_size,
+
+	ret = block_writer_init(&bw, BLOCK_TYPE_INDEX, (uint8_t *) block.buf, block_size,
 				header_off, hash_size(REFTABLE_HASH_SHA1));
 	check(!ret);
 
@@ -327,7 +331,8 @@ static void t_index_block_read_write(void)
 
 	block_writer_release(&bw);
 
-	block_reader_init(&br, &block, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
+	block_source_from_buf(&source, &block);
+	block_reader_init(&br, &source, 0, header_off, block_size, REFTABLE_HASH_SIZE_SHA1);
 
 	block_iter_seek_start(&it, &br);
 
@@ -365,9 +370,8 @@ static void t_index_block_read_write(void)
 	block_reader_release(&br);
 	block_iter_close(&it);
 	reftable_record_release(&rec);
-	block_source_return_block(&br.block);
 	reftable_buf_release(&want);
-	reftable_buf_release(&buf);
+	reftable_buf_release(&block);
 	for (i = 0; i < N; i++)
 		reftable_record_release(&recs[i]);
 }