Support CoroMapper method chaining (#1103)

orm_lib/inc/drogon/orm/CoroMapper.h

@@ -119,6 +119,74 @@ class CoroMapper : public Mapper<T>
             abort();
         }
     }
+
+    // Query condition overrides
+
+    /**
+     * @brief Add a limit to the query.
+     *
+     * @param limit The limit
+     * @return CoroMapper<T>& The CoroMapper itself.
+     */
+    CoroMapper<T> &limit(size_t limit)
+    {
+        Mapper<T>::limit(limit);
+        return *this;
+    }
+
+    /**
+     * @brief Add a offset to the query.
+     *
+     * @param offset The offset.
+     * @return CoroMapper<T>& The CoroMapper itself.
+     */
+    CoroMapper<T> &offset(size_t offset)
+    {
+        Mapper<T>::offset(offset);
+        return *this;
+    }
+
+    /**
+     * @brief Set the order of the results.
+     *
+     * @param colName the column name, the results are sorted by that column
+     * @param order Ascending or descending order
+     * @return CoroMapper<T>& The CoroMapper itself.
+     */
+    CoroMapper<T> &orderBy(const std::string &colName,
+                           const SortOrder &order = SortOrder::ASC)
+    {
+        Mapper<T>::orderBy(colName, order);
+        return *this;
+    }
+
+    /**
+     * @brief Set the order of the results.
+     *
+     * @param colIndex the column index, the results are sorted by that column
+     * @param order Ascending or descending order
+     * @return CoroMapper<T>& The CoroMapper itself.
+     */
+    CoroMapper<T> &orderBy(size_t colIndex,
+                           const SortOrder &order = SortOrder::ASC)
+    {
+        Mapper<T>::orderBy(colIndex, order);
+        return *this;
+    }
+
+    /**
+     * @brief Lock the result for updating.
+     *
+     * @return CoroMapper<T>& The CoroMapper itself.
+     */
+    CoroMapper<T> &forUpdate()
+    {
+        Mapper<T>::forUpdate();
+        return *this;
+    }
+
+    // Read api for coroutines
+
     inline internal::MapperAwaiter<std::vector<T>> findAll()
     {
         return findBy(Criteria());

orm_lib/tests/db_test.cc

@@ -666,6 +666,20 @@ DROGON_TEST(PostgreTest)
         {
             SUCCESS();
         }
+        try
+        {
+            CoroMapper<Users> mapper(clientPtr);
+            auto users = co_await mapper.orderBy(Users::Cols::_user_id)
+                             .limit(2)
+                             .findAll();
+            MANDATE(users.size() == 2);
+            SUCCESS();
+        }
+        catch (const DrogonDbException &e)
+        {
+            FAULT("postgresql - ORM mapper coroutine  interface(2) what():" +
+                  std::string(e.base().what()));
+        }
         /// 7.4 Transactions
         try
         {