refactor: rm operator+ from StringRef

include/base/string_ref.h

@@ -44,8 +44,8 @@ struct StringRef {
 
     ~StringRef() {}
 
-    const inline bool IsNull() const { return nullptr == data_; }
-    const std::string ToString() const {
+    inline bool IsNull() const { return nullptr == data_; }
+    std::string ToString() const {
         return size_ == 0 ? "" : std::string(data_, size_);
     }
 
@@ -82,22 +82,6 @@ struct StringRef {
     const char* data_;
 };
 
-__attribute__((unused)) static const StringRef operator+(const StringRef& a,
-                                                         const StringRef& b) {
-    StringRef str;
-    str.size_ = a.size_ + b.size_;
-    char* buffer = static_cast<char*>(malloc(str.size_ + 1));
-    str.data_ = buffer;
-    if (a.size_ > 0) {
-        memcpy(buffer, a.data_, a.size_);
-    }
-    if (b.size_ > 0) {
-        memcpy(buffer + a.size_, b.data_, b.size_);
-    }
-    buffer[str.size_] = '\0';
-    return str;
-}
-
 __attribute__((unused)) static std::ostream& operator<<(std::ostream& os,
                                                         const StringRef& a) {
     os << a.ToString();

include/base/type.h

@@ -22,7 +22,6 @@
 #include <cstddef>
 #include <ostream>
 #include <string>
-#include <vector>
 
 namespace openmldb {
 namespace base {
@@ -109,7 +108,7 @@ struct Date {
     }
 
     // | --- 16 bit -------------------------- | -- 8 bit ------------| --- 8 bit --------- |
-    // | year count since 1990 (starts from 0) | month(starts from 0) | day (starts from 1) |
+    // | year count since 1900 (starts from 0) | month(starts from 0) | day (starts from 1) |
     int32_t date_;
 
     friend std::ostream& operator<<(std::ostream& os, const Date& date) {

src/examples/test_udf.cc

@@ -16,6 +16,8 @@
 
 #include "udf/openmldb_udf.h"
 
+#include <vector>
+
 extern "C"
 void cut2(::openmldb::base::UDFContext* ctx, ::openmldb::base::StringRef* input, ::openmldb::base::StringRef* output) {
     if (input == nullptr || output == nullptr) {