t/helper: use hash_to_hex_algop() to print hashes

The "reftable" test helper uses a hand-crafted version to convert from a
raw hash to its hex variant. This was done because this code used to be
part of the reftable library, where we do not use most functions from
the Git core.

Now that the code is integrated into the "dump-reftable" helper though,
that limitation went away. Let's thus use `hash_to_hex_algop()` instead.

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

Author: pks-t

t/helper/test-reftable.c

@@ -1,3 +1,6 @@
+#include "git-compat-util.h"
+#include "hash.h"
+#include "hex.h"
 #include "reftable/system.h"
 #include "reftable/reftable-error.h"
 #include "reftable/reftable-generic.h"
@@ -30,33 +33,12 @@ static void print_help(void)
 	       "\n");
 }
 
-static char hexdigit(int c)
-{
-	if (c <= 9)
-		return '0' + c;
-	return 'a' + (c - 10);
-}
-
-static void hex_format(char *dest, const unsigned char *src, int hash_size)
-{
-	assert(hash_size > 0);
-	if (src) {
-		int i = 0;
-		for (i = 0; i < hash_size; i++) {
-			dest[2 * i] = hexdigit(src[i] >> 4);
-			dest[2 * i + 1] = hexdigit(src[i] & 0xf);
-		}
-		dest[2 * hash_size] = 0;
-	}
-}
-
 static int dump_table(struct reftable_table *tab)
 {
 	struct reftable_iterator it = { NULL };
 	struct reftable_ref_record ref = { NULL };
 	struct reftable_log_record log = { NULL };
-	uint32_t hash_id = reftable_table_hash_id(tab);
-	int hash_len = hash_size(hash_id);
+	const struct git_hash_algo *algop;
 	int err;
 
 	reftable_table_init_ref_iter(tab, &it);
@@ -65,9 +47,9 @@ static int dump_table(struct reftable_table *tab)
 	if (err < 0)
 		return err;
 
-	while (1) {
-		char hex[GIT_MAX_HEXSZ + 1] = { 0 }; /* BUG */
+	algop = &hash_algos[hash_algo_by_id(reftable_table_hash_id(tab))];
 
+	while (1) {
 		err = reftable_iterator_next_ref(&it, &ref);
 		if (err > 0)
 			break;
@@ -80,15 +62,11 @@ static int dump_table(struct reftable_table *tab)
 			printf("=> %s", ref.value.symref);
 			break;
 		case REFTABLE_REF_VAL2:
-			hex_format(hex, ref.value.val2.value, hash_len);
-			printf("val 2 %s", hex);
-			hex_format(hex, ref.value.val2.target_value,
-				   hash_len);
-			printf("(T %s)", hex);
+			printf("val 2 %s", hash_to_hex_algop(ref.value.val2.value, algop));
+			printf("(T %s)", hash_to_hex_algop(ref.value.val2.target_value, algop));
 			break;
 		case REFTABLE_REF_VAL1:
-			hex_format(hex, ref.value.val1, hash_len);
-			printf("val 1 %s", hex);
+			printf("val 1 %s", hash_to_hex_algop(ref.value.val1, algop));
 			break;
 		case REFTABLE_REF_DELETION:
 			printf("delete");
@@ -106,8 +84,6 @@ static int dump_table(struct reftable_table *tab)
 		return err;
 
 	while (1) {
-		char hex[GIT_MAX_HEXSZ + 1] = { 0 };
-
 		err = reftable_iterator_next_log(&it, &log);
 		if (err > 0)
 			break;
@@ -126,10 +102,8 @@ static int dump_table(struct reftable_table *tab)
 			       log.value.update.email ? log.value.update.email : "",
 			       log.value.update.time,
 			       log.value.update.tz_offset);
-			hex_format(hex, log.value.update.old_hash, hash_len);
-			printf("%s => ", hex);
-			hex_format(hex, log.value.update.new_hash, hash_len);
-			printf("%s\n\n%s\n}\n", hex,
+			printf("%s => ", hash_to_hex_algop(log.value.update.old_hash, algop));
+			printf("%s\n\n%s\n}\n", hash_to_hex_algop(log.value.update.new_hash, algop),
 			       log.value.update.message ? log.value.update.message : "");
 			break;
 		}