[scn] mv definition of SCN to dir of share

src/share/scn.h

@@ -0,0 +1,134 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+#ifndef OCEABASE_SHARE_SCN_
+#define OCEABASE_SHARE_SCN_
+#include "lib/ob_define.h"                      // Serialization
+#include "lib/utility/ob_print_utils.h"         // Print*
+namespace oceanbase {
+namespace share {
+
+const uint64_t OB_INVALID_SCN_VAL = UINT64_MAX;
+const uint64_t OB_MIN_SCN_TS_NS = 0;
+const uint64_t OB_BASE_SCN_TS_NS = 1;
+const uint64_t OB_MAX_SCN_TS_NS = (1UL << 62) - 1;     //4611686018427387903
+
+class SCN
+{
+public:
+  SCN() : val_(OB_INVALID_SCN_VAL) {}
+  void reset();
+  bool is_valid() const;
+  bool is_valid_and_not_min() const;
+  bool is_max() const;
+  bool is_min() const;
+  bool is_base_scn() const { return *this == base_scn(); }
+  void set_invalid();
+  void set_max();
+  void set_min();
+  void set_base();
+  static SCN invalid_scn();
+  static SCN max_scn();
+  static SCN min_scn();
+  static SCN base_scn();
+  static SCN max(const SCN &left, const SCN &right);
+  static SCN min(const SCN &left, const SCN &right);
+  static SCN plus(const SCN &ref, uint64_t delta);
+  static SCN minus(const SCN &ref, uint64_t delta);
+  static SCN scn_inc(const SCN &ref);
+  static SCN scn_dec(const SCN &ref);
+
+  void atomic_set(const SCN &ref);
+  SCN atomic_get() const;
+  bool atomic_bcas(const SCN &old_v, const SCN &new_val);
+  SCN atomic_vcas(const SCN &old_v, const SCN &new_val);
+  SCN inc_update(const SCN &ref_scn);
+  SCN dec_update(const SCN &ref_scn);
+  /*******convert functions******/
+  //[convert scn to timestamp(us)
+  // @result[out]: timestamp in us
+  int64_t convert_to_ts(bool ignore_invalid = false) const;
+
+  // @param[in] :timestamp with us
+  int convert_from_ts(uint64_t ts_us);
+
+  // convert time_ns generated by gts to scn. only used by gts
+  // @param[in] time_ns: time_ns generated by gts
+  int convert_for_gts(int64_t time_ns);
+
+  // convert id generated by lsn allocator. only used by logservice
+  // @param[in] id: id generated by lsn allocator
+  int convert_for_logservice(uint64_t scn_val);
+
+  // convert scn_related column value to scn. only used when extracting inner table query result
+  // @param[in] column_value: query result of scn_related column of inner table
+  int convert_for_inner_table_field(uint64_t column_value);
+
+  //convert function to sql
+  int convert_for_sql(uint64_t scn_val);
+
+  // @param[in] convert for tx: INT64_MAX may convert to MAX_SCN
+  int convert_for_tx(int64_t commit_trans_version);
+
+  // change val_ from INT64_MAX to OB_MAX_SCN_TS_NS for compitibility in
+  // deserialization
+  void transform_max();
+
+  //only for filling inner_table fields
+  uint64_t get_val_for_inner_table_field() const;
+
+  //only for gts use
+  uint64_t get_val_for_gts() const;
+
+  //only for log service use
+  uint64_t get_val_for_logservice() const;
+  //only for sql use
+  uint64_t get_val_for_sql() const;
+
+  //only for tx, include transform from SCN_MAX to INT64_MAX
+  int64_t get_val_for_tx() const;
+
+  // compare function
+  bool operator==(const SCN &scn) const;
+  bool operator!=(const SCN &scn) const;
+  bool operator<(const SCN &scn) const;
+  bool operator<=(const SCN &scn) const;
+  bool operator>(const SCN &scn) const;
+  bool operator>=(const SCN &scn) const;
+  SCN &operator=(const SCN &scn);
+
+  //fixed length serialization
+  int fixed_serialize(char* buf, const int64_t buf_len, int64_t& pos) const;
+  int fixed_deserialize(const char* buf, const int64_t data_len, int64_t& pos);
+  int64_t get_fixed_serialize_size(void) const;
+
+  //variable serialization
+  int serialize(char* buf, const int64_t buf_len, int64_t& pos) const;
+  int deserialize(const char* buf, const int64_t data_len, int64_t& pos);
+  int64_t get_serialize_size(void) const;
+  int to_yson(char *buf, const int64_t buf_len, int64_t &pos) const;
+
+  TO_STRING_KV(K_(val));
+private:
+  static const uint64_t SCN_VERSION = 0;
+  union {
+    uint64_t val_;
+    struct {
+      uint64_t ts_ns_ : 62;
+      uint64_t v_ : 2;
+    };
+  };
+};
+
+} // end namespace share
+} // end namespace oceanbase
+#endif