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reftable/blocksource: adjust read_block() to return ssize_t

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The `block_source_read_block()` function and its implementations return
an integer as a result that reflects either the number of bytes read, or
an error. As such its return type, a signed integer, isn't wrong, but it
doesn't give the reader a good hint what it actually returns.

Refactor the function to return an `ssize_t` instead, which is typical
for functions similar to read(3p) and should thus give readers a better
signal what they can expect as a result.

Adjust callers to better handle the returned value to avoid warnings
with -Wsign-compare. One of these callers is `reader_get_block()`, whose
return value is only ever used by its callers to figure out whether or
not the read was successful. So instead of bubbling up the `ssize_t`
there, too, we adapt it to only indicate success or errors.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Patrick Steinhardt
2025-01-20 17:17:27 +01:00
committed by Junio C Hamano
parent 1f054af72f
commit 7c4c1cbc0b
4 changed files with 31 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
reftable/blocksource.c
View File

@ -24,8 +24,8 @@ static void reftable_buf_close(void *b UNUSED)
{
}
static int reftable_buf_read_block(void *v, struct reftable_block *dest,
uint64_t off, uint32_t size)
static ssize_t reftable_buf_read_block(void *v, struct reftable_block *dest,
uint64_t off, uint32_t size)
{
struct reftable_buf *b = v;
assert(off + size <= b->len);
@ -78,8 +78,8 @@ static void file_close(void *v)
reftable_free(b);
}
static int file_read_block(void *v, struct reftable_block *dest, uint64_t off,
uint32_t size)
static ssize_t file_read_block(void *v, struct reftable_block *dest, uint64_t off,
uint32_t size)
{
struct file_block_source *b = v;
assert(off + size <= b->size);

30
reftable/reader.c
View File

@ -20,11 +20,11 @@ uint64_t block_source_size(struct reftable_block_source *source)
return source->ops->size(source->arg);
}
int block_source_read_block(struct reftable_block_source *source,
struct reftable_block *dest, uint64_t off,
uint32_t size)
ssize_t block_source_read_block(struct reftable_block_source *source,
struct reftable_block *dest, uint64_t off,
uint32_t size)
{
int result = source->ops->read_block(source->arg, dest, off, size);
ssize_t result = source->ops->read_block(source->arg, dest, off, size);
dest->source = *source;
return result;
}
@ -57,14 +57,17 @@ static int reader_get_block(struct reftable_reader *r,
struct reftable_block *dest, uint64_t off,
uint32_t sz)
{
ssize_t bytes_read;
if (off >= r->size)
return 0;
if (off + sz > r->size) {
if (off + sz > r->size)
sz = r->size - off;
}
return block_source_read_block(&r->source, dest, off, sz);
bytes_read = block_source_read_block(&r->source, dest, off, sz);
if (bytes_read < 0)
return (int)bytes_read;
return 0;
}
enum reftable_hash reftable_reader_hash_id(struct reftable_reader *r)
@ -601,6 +604,7 @@ int reftable_reader_new(struct reftable_reader **out,
struct reftable_reader *r;
uint64_t file_size = block_source_size(source);
uint32_t read_size;
ssize_t bytes_read;
int err;
REFTABLE_CALLOC_ARRAY(r, 1);
@ -619,8 +623,8 @@ int reftable_reader_new(struct reftable_reader **out,
goto done;
}
err = block_source_read_block(source, &header, 0, read_size);
if (err != read_size) {
bytes_read = block_source_read_block(source, &header, 0, read_size);
if (bytes_read < 0 || (size_t)bytes_read != read_size) {
err = REFTABLE_IO_ERROR;
goto done;
}
@ -645,9 +649,9 @@ int reftable_reader_new(struct reftable_reader **out,
r->hash_id = 0;
r->refcount = 1;
err = block_source_read_block(source, &footer, r->size,
footer_size(r->version));
if (err != footer_size(r->version)) {
bytes_read = block_source_read_block(source, &footer, r->size,
footer_size(r->version));
if (bytes_read < 0 || (size_t)bytes_read != footer_size(r->version)) {
err = REFTABLE_IO_ERROR;
goto done;
}

6
reftable/reader.h
View File

@ -16,9 +16,9 @@ https://developers.google.com/open-source/licenses/bsd
uint64_t block_source_size(struct reftable_block_source *source);
int block_source_read_block(struct reftable_block_source *source,
struct reftable_block *dest, uint64_t off,
uint32_t size);
ssize_t block_source_read_block(struct reftable_block_source *source,
struct reftable_block *dest, uint64_t off,
uint32_t size);
void block_source_close(struct reftable_block_source *source);
/* metadata for a block type */

11
reftable/reftable-blocksource.h
View File

@ -31,10 +31,13 @@ struct reftable_block_source_vtable {
/* returns the size of a block source */
uint64_t (*size)(void *source);
/* reads a segment from the block source. It is an error to read
beyond the end of the block */
int (*read_block)(void *source, struct reftable_block *dest,
uint64_t off, uint32_t size);
/*
* Reads a segment from the block source. It is an error to read beyond
* the end of the block.
*/
ssize_t (*read_block)(void *source, struct reftable_block *dest,
uint64_t off, uint32_t size);
/* mark the block as read; may return the data back to malloc */
void (*return_block)(void *source, struct reftable_block *blockp);