refactor type system (#439)

### What problem were solved in this pull request?
refactor type system, types are implemented based on `DataType`, which
facilitates extension of the types.

---------

Co-authored-by: wangyunlai <[email protected]>

deps/common/lang/array.h

@@ -0,0 +1,15 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+#pragma once
+
+#include <array>
+
+using std::array;

deps/common/lang/comparator.cpp

@@ -53,15 +53,15 @@ int compare_string(void *arg1, int arg1_max_length, void *arg2, int arg2_max_len
   int         maxlen = min(arg1_max_length, arg2_max_length);
   int         result = strncmp(s1, s2, maxlen);
   if (0 != result) {
-    return result;
+    return result < 0 ? -1 : 1;
   }
 
   if (arg1_max_length > maxlen) {
-    return s1[maxlen] - 0;
+    return 1;
   }
 
   if (arg2_max_length > maxlen) {
-    return 0 - s2[maxlen];
+    return -1;
   }
   return 0;
 }

deps/common/lang/string.h

@@ -18,6 +18,7 @@ See the Mulan PSL v2 for more details. */
 #include <cxxabi.h>
 #include <signal.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include <cstdlib>
 #include <string>

src/observer/common/rc.h

@@ -22,7 +22,7 @@ See the Mulan PSL v2 for more details. */
 #define DEFINE_RCS                       \
   DEFINE_RC(SUCCESS)                     \
   DEFINE_RC(INVALID_ARGUMENT)            \
-  DEFINE_RC(UNIMPLENMENT)                \
+  DEFINE_RC(UNIMPLEMENTED)               \
   DEFINE_RC(SQL_SYNTAX)                  \
   DEFINE_RC(INTERNAL)                    \
   DEFINE_RC(NOMEM)                       \
@@ -75,7 +75,8 @@ See the Mulan PSL v2 for more details. */
   DEFINE_RC(VARIABLE_NOT_VALID)          \
   DEFINE_RC(LOGBUF_FULL)                 \
   DEFINE_RC(LOG_FILE_FULL)               \
-  DEFINE_RC(LOG_ENTRY_INVALID)
+  DEFINE_RC(LOG_ENTRY_INVALID)           \
+  DEFINE_RC(UNSUPPORTED)
 
 enum class RC
 {

src/observer/common/type/attr_type.cpp

@@ -0,0 +1,33 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+
+#include "common/lang/string.h"
+#include "common/type/attr_type.h"
+
+const char *ATTR_TYPE_NAME[] = {"undefined", "chars", "ints", "floats", "booleans"};
+
+const char *attr_type_to_string(AttrType type)
+{
+  if (type >= AttrType::UNDEFINED && type < AttrType::MAXTYPE) {
+    return ATTR_TYPE_NAME[static_cast<int>(type)];
+  }
+  return "unknown";
+}
+
+AttrType attr_type_from_string(const char *s)
+{
+  for (unsigned int i = 0; i < sizeof(ATTR_TYPE_NAME) / sizeof(ATTR_TYPE_NAME[0]); i++) {
+    if (0 == strcasecmp(ATTR_TYPE_NAME[i], s)) {
+      return (AttrType)i;
+    }
+  }
+  return AttrType::UNDEFINED;
+}

src/observer/common/type/attr_type.h

@@ -0,0 +1,28 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+#pragma once
+
+/**
+ * @brief 属性的类型
+ * @details AttrType 枚举列出了属性的各种数据类型。
+ */
+enum class AttrType
+{
+  UNDEFINED,
+  CHARS,     ///< 字符串类型
+  INTS,      ///< 整数类型(4字节)
+  FLOATS,    ///< 浮点数类型(4字节)
+  BOOLEANS,  ///< boolean类型，当前不是由parser解析出来的，是程序内部使用的
+  MAXTYPE,   ///< 请在 UNDEFINED 与 MAXTYPE 之间增加新类型
+};
+
+const char *attr_type_to_string(AttrType type);
+AttrType    attr_type_from_string(const char *s);

src/observer/common/type/char_type.cpp

@@ -0,0 +1,51 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+#include "common/lang/comparator.h"
+#include "common/log/log.h"
+#include "common/type/char_type.h"
+#include "common/value.h"
+
+int CharType::compare(const Value &left, const Value &right) const
+{
+  ASSERT(left.attr_type() == AttrType::CHARS && right.attr_type() == AttrType::CHARS, "invalid type");
+  return common::compare_string(
+      (void *)left.value_.pointer_value_, left.length_, (void *)right.value_.pointer_value_, right.length_);
+}
+
+RC CharType::set_value_from_str(Value &val, const string &data) const
+{
+  val.set_string(data.c_str());
+  return RC::SUCCESS;
+}
+
+RC CharType::cast_to(const Value &val, AttrType type, Value &result) const
+{
+  switch (type) {
+    default: return RC::UNIMPLEMENTED;
+  }
+  return RC::SUCCESS;
+}
+
+int CharType::cast_cost(AttrType type)
+{
+  if (type == AttrType::CHARS) {
+    return 0;
+  }
+  return INT32_MAX;
+}
+
+RC CharType::to_string(const Value &val, string &result) const
+{
+  stringstream ss;
+  ss << val.value_.pointer_value_;
+  result = ss.str();
+  return RC::SUCCESS;
+}

src/observer/common/type/char_type.h

@@ -0,0 +1,36 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+#pragma once
+
+#include "common/rc.h"
+#include "common/type/data_type.h"
+
+/**
+ * @brief 固定长度的字符串类型
+ * @ingroup DataType
+ */
+class CharType : public DataType
+{
+public:
+  CharType() : DataType(AttrType::CHARS) {}
+
+  virtual ~CharType() = default;
+
+  int compare(const Value &left, const Value &right) const override;
+
+  RC cast_to(const Value &val, AttrType type, Value &result) const override;
+
+  RC set_value_from_str(Value &val, const string &data) const override;
+
+  int cast_cost(AttrType type) override;
+
+  RC to_string(const Value &val, string &result) const override;
+};

src/observer/common/type/data_type.cpp

@@ -0,0 +1,22 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+#include "common/type/char_type.h"
+#include "common/type/float_type.h"
+#include "common/type/integer_type.h"
+#include "common/type/data_type.h"
+
+array<unique_ptr<DataType>, static_cast<int>(AttrType::MAXTYPE)> DataType::type_instances_ = {
+    make_unique<DataType>(AttrType::UNDEFINED),
+    make_unique<CharType>(),
+    make_unique<IntegerType>(),
+    make_unique<FloatType>(),
+    make_unique<DataType>(AttrType::BOOLEANS),
+};

src/observer/common/type/data_type.h

@@ -0,0 +1,102 @@
+/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
+miniob is licensed under Mulan PSL v2.
+You can use this software according to the terms and conditions of the Mulan PSL v2.
+You may obtain a copy of Mulan PSL v2 at:
+         http://license.coscl.org.cn/MulanPSL2
+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 PSL v2 for more details. */
+
+#pragma once
+
+#include "common/lang/array.h"
+#include "common/lang/memory.h"
+#include "common/lang/string.h"
+#include "common/rc.h"
+#include "common/type/attr_type.h"
+
+class Value;
+
+/**
+ * @brief 定义了数据类型相关的操作，比如比较运算、算术运算等
+ * @defgroup 数据类型
+ * @details 数据类型定义的算术运算中，比如 add、subtract 等，将按照当前数据类型设置最终结果值的类型。
+ * 参与运算的参数类型不一定相同，不同的类型进行运算是否能够支持需要参考各个类型的实现。
+ */
+class DataType
+{
+public:
+  explicit DataType(AttrType attr_type) : attr_type_(attr_type) {}
+
+  virtual ~DataType() = default;
+
+  inline static DataType *type_instance(AttrType attr_type)
+  {
+    return type_instances_.at(static_cast<int>(attr_type)).get();
+  }
+
+  inline AttrType get_attr_type() const { return attr_type_; }
+
+  /**
+   * @return
+   *  -1 表示 left < right
+   *  0 表示 left = right
+   *  1 表示 left > right
+   *  INT32_MAX 表示未实现的比较
+   */
+  virtual int compare(const Value &left, const Value &right) const { return INT32_MAX; }
+
+  /**
+   * @brief 计算 left + right，并将结果保存到 result 中
+   */
+  virtual RC add(const Value &left, const Value &right, Value &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 计算 left - right，并将结果保存到 result 中
+   */
+  virtual RC subtract(const Value &left, const Value &right, Value &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 计算 left * right，并将结果保存到 result 中
+   */
+  virtual RC multiply(const Value &left, const Value &right, Value &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 计算 left / right，并将结果保存到 result 中
+   */
+  virtual RC divide(const Value &left, const Value &right, Value &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 计算 -val，并将结果保存到 result 中
+   */
+  virtual RC negative(const Value &val, Value &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 将 val 转换为 type 类型，并将结果保存到 result 中
+   */
+  virtual RC cast_to(const Value &val, AttrType type, Value &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 将 val 转换为 string，并将结果保存到 result 中
+   */
+  virtual RC to_string(const Value &val, string &result) const { return RC::UNSUPPORTED; }
+
+  /**
+   * @brief 计算从 type 到 attr_type 的隐式转换的 cost，如果无法转换，返回 INT32_MAX
+   */
+  virtual int cast_cost(AttrType type)
+  {
+    if (type == attr_type_) {
+      return 0;
+    }
+    return INT32_MAX;
+  }
+
+  virtual RC set_value_from_str(Value &val, const string &data) const { return RC::UNSUPPORTED; }
+
+protected:
+  AttrType attr_type_;
+
+  static array<unique_ptr<DataType>, static_cast<int>(AttrType::MAXTYPE)> type_instances_;
+};