reftable: introduce REFTABLE_FREE_AND_NULL()

We have several calls to `FREE_AND_NULL()` in the reftable library,
which of course uses free(3P). As the reftable allocators are pluggable
we should rather call the reftable specific function, which is
`reftable_free()`.

Introduce a new macro `REFTABLE_FREE_AND_NULL()` and adapt the callsites
accordingly.

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

Author: pks-t

reftable/basics.h

@@ -71,6 +71,7 @@ char *reftable_strdup(const char *str);
 			REFTABLE_REALLOC_ARRAY(x, alloc); \
 		} \
 	} while (0)
+#define REFTABLE_FREE_AND_NULL(p) do { reftable_free(p); (p) = NULL; } while (0)
 
 /* Find the longest shared prefix size of `a` and `b` */
 struct strbuf;

reftable/block.c

@@ -551,9 +551,9 @@ int block_iter_seek_key(struct block_iter *it, const struct block_reader *br,
 void block_writer_release(struct block_writer *bw)
 {
 	deflateEnd(bw->zstream);
-	FREE_AND_NULL(bw->zstream);
-	FREE_AND_NULL(bw->restarts);
-	FREE_AND_NULL(bw->compressed);
+	REFTABLE_FREE_AND_NULL(bw->zstream);
+	REFTABLE_FREE_AND_NULL(bw->restarts);
+	REFTABLE_FREE_AND_NULL(bw->compressed);
 	strbuf_release(&bw->last_key);
 	/* the block is not owned. */
 }

reftable/iter.c

@@ -237,7 +237,7 @@ void reftable_iterator_destroy(struct reftable_iterator *it)
 		return;
 	it->ops->close(it->iter_arg);
 	it->ops = NULL;
-	FREE_AND_NULL(it->iter_arg);
+	REFTABLE_FREE_AND_NULL(it->iter_arg);
 }
 
 int reftable_iterator_seek_ref(struct reftable_iterator *it,

reftable/pq.c

@@ -68,6 +68,6 @@ int merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry
 
 void merged_iter_pqueue_release(struct merged_iter_pqueue *pq)
 {
-	FREE_AND_NULL(pq->heap);
+	REFTABLE_FREE_AND_NULL(pq->heap);
 	memset(pq, 0, sizeof(*pq));
 }

reftable/reader.c

@@ -678,7 +678,7 @@ void reftable_reader_decref(struct reftable_reader *r)
 	if (--r->refcount)
 		return;
 	block_source_close(&r->source);
-	FREE_AND_NULL(r->name);
+	REFTABLE_FREE_AND_NULL(r->name);
 	reftable_free(r);
 }
 

reftable/record.c

@@ -476,8 +476,8 @@ static void reftable_obj_record_key(const void *r, struct strbuf *dest)
 static void reftable_obj_record_release(void *rec)
 {
 	struct reftable_obj_record *obj = rec;
-	FREE_AND_NULL(obj->hash_prefix);
-	FREE_AND_NULL(obj->offsets);
+	REFTABLE_FREE_AND_NULL(obj->hash_prefix);
+	REFTABLE_FREE_AND_NULL(obj->offsets);
 	memset(obj, 0, sizeof(struct reftable_obj_record));
 }
 
@@ -834,10 +834,10 @@ static int reftable_log_record_decode(void *rec, struct strbuf key,
 	if (val_type != r->value_type) {
 		switch (r->value_type) {
 		case REFTABLE_LOG_UPDATE:
-			FREE_AND_NULL(r->value.update.message);
+			REFTABLE_FREE_AND_NULL(r->value.update.message);
 			r->value.update.message_cap = 0;
-			FREE_AND_NULL(r->value.update.email);
-			FREE_AND_NULL(r->value.update.name);
+			REFTABLE_FREE_AND_NULL(r->value.update.email);
+			REFTABLE_FREE_AND_NULL(r->value.update.name);
 			break;
 		case REFTABLE_LOG_DELETION:
 			break;

reftable/stack.c

@@ -203,7 +203,7 @@ void reftable_stack_destroy(struct reftable_stack *st)
 
 	err = read_lines(st->list_file, &names);
 	if (err < 0) {
-		FREE_AND_NULL(names);
+		REFTABLE_FREE_AND_NULL(names);
 	}
 
 	if (st->readers) {
@@ -224,16 +224,16 @@ void reftable_stack_destroy(struct reftable_stack *st)
 		}
 		strbuf_release(&filename);
 		st->readers_len = 0;
-		FREE_AND_NULL(st->readers);
+		REFTABLE_FREE_AND_NULL(st->readers);
 	}
 
 	if (st->list_fd >= 0) {
 		close(st->list_fd);
 		st->list_fd = -1;
 	}
 
-	FREE_AND_NULL(st->list_file);
-	FREE_AND_NULL(st->reftable_dir);
+	REFTABLE_FREE_AND_NULL(st->list_file);
+	REFTABLE_FREE_AND_NULL(st->reftable_dir);
 	reftable_free(st);
 	free_names(names);
 }

reftable/writer.c

@@ -593,7 +593,7 @@ static void object_record_free(void *void_arg UNUSED, void *key)
 {
 	struct obj_index_tree_node *entry = key;
 
-	FREE_AND_NULL(entry->offsets);
+	REFTABLE_FREE_AND_NULL(entry->offsets);
 	strbuf_release(&entry->hash);
 	reftable_free(entry);
 }
@@ -709,7 +709,7 @@ static void writer_clear_index(struct reftable_writer *w)
 {
 	for (size_t i = 0; w->index && i < w->index_len; i++)
 		strbuf_release(&w->index[i].last_key);
-	FREE_AND_NULL(w->index);
+	REFTABLE_FREE_AND_NULL(w->index);
 	w->index_len = 0;
 	w->index_cap = 0;
 }

t/unit-tests/t-reftable-stack.c

@@ -1149,7 +1149,7 @@ static void unclean_stack_close(struct reftable_stack *st)
 	for (size_t i = 0; i < st->readers_len; i++)
 		reftable_reader_decref(st->readers[i]);
 	st->readers_len = 0;
-	FREE_AND_NULL(st->readers);
+	REFTABLE_FREE_AND_NULL(st->readers);
 }
 
 static void t_reftable_stack_compaction_concurrent_clean(void)