reftable/blocksource: drop malloc block source

The reftable blocksource provides a generic interface to read blocks via
different sources, e.g. from disk or from memory. One of the block
sources is the malloc block source, which can in theory read data from
memory. We nowadays also have a strbuf block source though, which
provides essentially the same functionality with better ergonomics.

Adapt the only remaining user of the malloc block source in our tests
to use the strbuf block source, instead, and remove the now-unused
malloc block source.

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

Author: pks-t

reftable/block_test.c

@@ -34,11 +34,12 @@ static void test_block_read_write(void)
 	struct block_reader br = { 0 };
 	struct block_iter it = BLOCK_ITER_INIT;
 	int j = 0;
+	struct strbuf block_data = STRBUF_INIT;
 	struct strbuf want = STRBUF_INIT;
 
 	REFTABLE_CALLOC_ARRAY(block.data, block_size);
 	block.len = block_size;
-	block.source = malloc_block_source();
+	block_source_from_strbuf(&block.source, &block_data);
 	block_writer_init(&bw, BLOCK_TYPE_REF, block.data, block_size,
 			  header_off, hash_size(GIT_SHA1_FORMAT_ID));
 

reftable/blocksource.c

@@ -55,26 +55,6 @@ void block_source_from_strbuf(struct reftable_block_source *bs,
 	bs->arg = buf;
 }
 
-static void malloc_return_block(void *b, struct reftable_block *dest)
-{
-	if (dest->len)
-		memset(dest->data, 0xff, dest->len);
-	reftable_free(dest->data);
-}
-
-static struct reftable_block_source_vtable malloc_vtable = {
-	.return_block = &malloc_return_block,
-};
-
-static struct reftable_block_source malloc_block_source_instance = {
-	.ops = &malloc_vtable,
-};
-
-struct reftable_block_source malloc_block_source(void)
-{
-	return malloc_block_source_instance;
-}
-
 struct file_block_source {
 	uint64_t size;
 	unsigned char *data;

reftable/blocksource.h

@@ -17,6 +17,4 @@ struct reftable_block_source;
 void block_source_from_strbuf(struct reftable_block_source *bs,
 			      struct strbuf *buf);
 
-struct reftable_block_source malloc_block_source(void);
-
 #endif