From a873701765e00228463e06795bdde21274e8fa74 Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Wed, 27 May 2015 22:49:20 +0200
Subject: [PATCH] store: Let sdb_store_json_formatter_t inherit from
 sdb_object_t.

---
 src/core/store_exec.c         | 12 ++++----
 src/core/store_json.c         | 55 ++++++++++++++++++++++-------------
 src/include/core/store.h      |  3 ++
 t/unit/core/store_json_test.c |  2 +-
 4 files changed, 44 insertions(+), 28 deletions(-)

diff --git a/src/core/store_exec.c b/src/core/store_exec.c
index 436b36e..6a8e8e7 100644
--- a/src/core/store_exec.c
+++ b/src/core/store_exec.c
@@ -138,14 +138,14 @@ exec_fetch(sdb_strbuf_t *buf, sdb_strbuf_t *errbuf, int type,
 				"%s %s.%s to JSON", SDB_STORE_TYPE_TO_NAME(type),
 				hostname, name);
 		sdb_strbuf_sprintf(errbuf, "Out of memory");
-		free(f);
+		sdb_object_deref(SDB_OBJ(f));
 		sdb_object_deref(SDB_OBJ(obj));
 		return -1;
 	}
 
 	sdb_object_deref(SDB_OBJ(obj));
 	sdb_store_json_finish(f);
-	free(f);
+	sdb_object_deref(SDB_OBJ(f));
 
 	return SDB_CONNECTION_DATA;
 } /* exec_fetch */
@@ -173,12 +173,12 @@ exec_list(sdb_strbuf_t *buf, sdb_strbuf_t *errbuf, int type,
 		sdb_log(SDB_LOG_ERR, "frontend: Failed to serialize "
 				"store to JSON");
 		sdb_strbuf_sprintf(errbuf, "Out of memory");
-		free(f);
+		sdb_object_deref(SDB_OBJ(f));
 		return -1;
 	}
 
 	sdb_store_json_finish(f);
-	free(f);
+	sdb_object_deref(SDB_OBJ(f));
 
 	return SDB_CONNECTION_DATA;
 } /* exec_list */
@@ -208,12 +208,12 @@ exec_lookup(sdb_strbuf_t *buf, sdb_strbuf_t *errbuf, int type,
 				SDB_STORE_TYPE_TO_NAME(type));
 		sdb_strbuf_sprintf(errbuf, "Failed to lookup %ss",
 				SDB_STORE_TYPE_TO_NAME(type));
-		free(f);
+		sdb_object_deref(SDB_OBJ(f));
 		return -1;
 	}
 
 	sdb_store_json_finish(f);
-	free(f);
+	sdb_object_deref(SDB_OBJ(f));
 
 	return SDB_CONNECTION_DATA;
 } /* exec_lookup */
diff --git a/src/core/store_json.c b/src/core/store_json.c
index 7362691..878cc4f 100644
--- a/src/core/store_json.c
+++ b/src/core/store_json.c
@@ -48,6 +48,9 @@
  */
 
 struct sdb_store_json_formatter {
+	sdb_object_t super;
+
+	/* The string buffer to write to */
 	sdb_strbuf_t *buf;
 
 	/* The context describes the state of the formatter through
@@ -61,6 +64,35 @@ struct sdb_store_json_formatter {
 	int type;
 	int flags;
 };
+#define F(obj) ((sdb_store_json_formatter_t *)(obj))
+
+static int
+formatter_init(sdb_object_t *obj, va_list ap)
+{
+	sdb_store_json_formatter_t *f = F(obj);
+
+	f->buf = va_arg(ap, sdb_strbuf_t *);
+	if (! f->buf)
+		return -1;
+
+	f->type = va_arg(ap, int);
+	if ((f->type != SDB_HOST) && (f->type != SDB_SERVICE) && (f->type != SDB_METRIC))
+		return -1;
+
+	f->flags = va_arg(ap, int);
+
+	f->context[0] = 0;
+	f->current = 0;
+
+	f->current_host = NULL;
+	return 0;
+} /* formatter_init */
+
+static sdb_type_t formatter_type = {
+	/* size = */ sizeof(sdb_store_json_formatter_t),
+	/* init = */ formatter_init,
+	/* destroy = */ NULL,
+};
 
 /*
  * private helper functions
@@ -169,27 +201,8 @@ json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj)
 sdb_store_json_formatter_t *
 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags)
 {
-	sdb_store_json_formatter_t *f;
-
-	if (! buf)
-		return NULL;
-
-	if ((type != SDB_HOST) && (type != SDB_SERVICE) && (type != SDB_METRIC))
-		return NULL;
-
-	f = calloc(1, sizeof(*f));
-	if (! f)
-		return NULL;
-
-	f->buf = buf;
-	f->context[0] = 0;
-	f->current = 0;
-
-	f->current_host = NULL;
-
-	f->type = type;
-	f->flags = flags;
-	return f;
+	return F(sdb_object_create("json-formatter", formatter_type,
+				buf, type, flags));
 } /* sdb_store_json_formatter */
 
 int
diff --git a/src/include/core/store.h b/src/include/core/store.h
index 20ca047..289bc2f 100644
--- a/src/include/core/store.h
+++ b/src/include/core/store.h
@@ -144,6 +144,9 @@ typedef struct sdb_store_matcher sdb_store_matcher_t;
 /*
  * A JSON formatter converts stored objects into the JSON format.
  * See http://www.ietf.org/rfc/rfc4627.txt
+ *
+ * A JSON formatter object inherits from sdb_object_t and, thus, may safely be
+ * cast to a generic object.
  */
 struct sdb_store_json_formatter;
 typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
diff --git a/t/unit/core/store_json_test.c b/t/unit/core/store_json_test.c
index baecf80..6be3c14 100644
--- a/t/unit/core/store_json_test.c
+++ b/t/unit/core/store_json_test.c
@@ -486,8 +486,8 @@ START_TEST(test_store_tojson)
 
 	verify_json_output(buf, store_tojson_data[_i].expected);
 
-	free(f);
 	sdb_object_deref(SDB_OBJ(filter));
+	sdb_object_deref(SDB_OBJ(f));
 	sdb_strbuf_destroy(buf);
 }
 END_TEST
-- 
2.30.2