From 739d378d2a0346b223c54acbb55d292335c276cb Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Mon, 13 Oct 2014 09:07:37 +0200
Subject: [PATCH] store: sdb_store_get_field: Make result parameter optional.

---
 src/core/store.c         | 19 +++++++++++--------
 src/include/core/store.h |  3 ++-
 t/unit/core/store_test.c | 15 +++++++++++----
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/core/store.c b/src/core/store.c
index f4f2b58..94b823b 100644
--- a/src/core/store.c
+++ b/src/core/store.c
@@ -896,7 +896,7 @@ sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res)
 {
 	sdb_data_t tmp;
 
-	if ((! obj) || (! res))
+	if (! obj)
 		return -1;
 
 	switch (field) {
@@ -905,19 +905,18 @@ sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res)
 			tmp.data.string = strdup(SDB_OBJ(obj)->name);
 			if (! tmp.data.string)
 				return -1;
-			*res = tmp;
 			break;
 		case SDB_FIELD_LAST_UPDATE:
-			res->type = SDB_TYPE_DATETIME;
-			res->data.datetime = obj->last_update;
+			tmp.type = SDB_TYPE_DATETIME;
+			tmp.data.datetime = obj->last_update;
 			break;
 		case SDB_FIELD_AGE:
-			res->type = SDB_TYPE_DATETIME;
-			res->data.datetime = sdb_gettime() - obj->last_update;
+			tmp.type = SDB_TYPE_DATETIME;
+			tmp.data.datetime = sdb_gettime() - obj->last_update;
 			break;
 		case SDB_FIELD_INTERVAL:
-			res->type = SDB_TYPE_DATETIME;
-			res->data.datetime = obj->interval;
+			tmp.type = SDB_TYPE_DATETIME;
+			tmp.data.datetime = obj->interval;
 			break;
 		case SDB_FIELD_BACKEND:
 			/* TODO: add support for storing array values in a data object
@@ -925,6 +924,10 @@ sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res)
 		default:
 			return -1;
 	}
+	if (res)
+		*res = tmp;
+	else
+		sdb_data_free_datum(&tmp);
 	return 0;
 } /* sdb_store_get_field */
 
diff --git a/src/include/core/store.h b/src/include/core/store.h
index 90416a2..7aeb287 100644
--- a/src/include/core/store.h
+++ b/src/include/core/store.h
@@ -241,7 +241,8 @@ sdb_store_fetch_timeseries(const char *hostname, const char *metric,
  * sdb_store_get_field:
  * Get the value of a stored object's queryable field. The caller is
  * responsible for freeing any dynamically allocated memory possibly stored in
- * the returned value.
+ * the returned value. If 'res' is NULL, the function will return whether the
+ * field exists.
  *
  * Note: Retrieving the backend this way is not currently supported.
  *
diff --git a/t/unit/core/store_test.c b/t/unit/core/store_test.c
index 00e3c64..c1071fb 100644
--- a/t/unit/core/store_test.c
+++ b/t/unit/core/store_test.c
@@ -723,15 +723,22 @@ START_TEST(test_get_field)
 	fail_unless(check < 0,
 			"sdb_store_get_field(NULL, SDB_FIELD_LAST_UPDATE, NULL) = %d; "
 			"expected: <0");
-	check = sdb_store_get_field(host, SDB_FIELD_LAST_UPDATE, NULL);
-	fail_unless(check < 0,
-			"sdb_store_get_field(<host>, SDB_FIELD_LAST_UPDATE, NULL) = %d; "
-			"expected: <0");
 	check = sdb_store_get_field(NULL, SDB_FIELD_LAST_UPDATE, &value);
 	fail_unless(check < 0,
 			"sdb_store_get_field(NULL, SDB_FIELD_LAST_UPDATE, <value>) = %d; "
 			"expected: <0");
 
+	check = sdb_store_get_field(host, SDB_FIELD_LAST_UPDATE, NULL);
+	fail_unless(check == 0,
+			"sdb_store_get_field(<host>, SDB_FIELD_LAST_UPDATE, NULL) = %d; "
+			"expected: 0");
+	/* 'name' is dynamically allocated; make sure it's not leaked even
+	 * if there is no result parameter */
+	check = sdb_store_get_field(host, SDB_FIELD_NAME, NULL);
+	fail_unless(check == 0,
+			"sdb_store_get_field(<host>, SDB_FIELD_LAST_UPDATE, NULL) = %d; "
+			"expected: 0");
+
 	check = sdb_store_get_field(host, SDB_FIELD_NAME, &value);
 	fail_unless(check == 0,
 			"sdb_store_get_field(<host>, SDB_FIELD_NAME, <value>) = "
-- 
2.30.2