add reference count module

src/util/inc/tref.h

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TDENGINE_TREF_H
+#define TDENGINE_TREF_H
+
+#include "os.h"
+
+typedef void (*_ref_fn_t)(const void* pObj);
+
+#define T_REF_DECLARE() \
+  struct {              \
+    int16_t val;        \
+  } _ref;
+
+#define T_REF_REGISTER_FUNC(s, e) \
+  struct {                        \
+    _ref_fn_t start;              \
+    _ref_fn_t end;                \
+  } _ref_func = {.begin = (s), .end = (e)};
+
+#define T_REF_INC(x) (atomic_add_fetch_16(&((x)->_ref.val), 1));
+
+#define T_REF_INC_WITH_CB(x, p)                           \
+  do {                                                    \
+    int32_t v = atomic_add_fetch_32(&((x)->_ref.val), 1); \
+    if (v == 1 && (p)->_ref_func.begin != NULL) {         \
+      (p)->_ref_func.begin((x));                          \
+    }                                                     \
+  } while (0)
+
+#define T_REF_DEC(x) (atomic_sub_fetch_16(&((x)->_ref.val), 1));
+
+#define T_REF_DEC_WITH_CB(x, p)                           \
+  do {                                                    \
+    int32_t v = atomic_sub_fetch_16(&((x)->_ref.val), 1); \
+    if (v == 0 && (p)->_ref_func.end != NULL) {           \
+      (p)->_ref_func.end((x));                            \
+    }                                                     \
+  } while (0)
+
+#define T_REF_VAL_CHECK(x) assert((x)->_ref.val >= 0);
+
+#define T_REF_VAL_GET(x) (x)->_ref.val
+
+#endif  // TDENGINE_TREF_H