[KYUUBI #1923] Add GetFunctions for trino engine

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### _Why are the changes needed?_
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Add GetFunctions for trino engine.

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [x] [Run test](https://kyuubi.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request

Closes #1925 from SteNicholas/KYUUBI-1923.

Closes #1923

4ebc64a [SteNicholas] [KYUUBI #1923] Add GetFunctions for trino engine
f19f518 [SteNicholas] [KYUUBI #1923] Add GetFunctions for trino engine
ac9df0a [SteNicholas] [KYUUBI #1923] Add GetFunctions for trino engine

Authored-by: SteNicholas <programgeek@163.com>
Signed-off-by: Kent Yao <yao@apache.org>

Author: SteNicholas

externals/kyuubi-trino-engine/src/main/scala/org/apache/kyuubi/engine/trino/operation/TrinoOperation.scala

@@ -98,7 +98,10 @@ abstract class TrinoOperation(opType: OperationType, session: Session)
   override def close(): Unit = {
     cleanup(OperationState.CLOSED)
     try {
-      trino.close()
+      if (trino != null) {
+        trino.close()
+        trino = null
+      }
       getOperationLog.foreach(_.close())
     } catch {
       case e: IOException =>

externals/kyuubi-trino-engine/src/main/scala/org/apache/kyuubi/engine/trino/operation/TrinoOperationManager.scala

@@ -21,6 +21,7 @@ import java.util
 
 import scala.collection.JavaConverters._
 
+import org.apache.kyuubi.KyuubiSQLException
 import org.apache.kyuubi.config.KyuubiConf.OPERATION_INCREMENTAL_COLLECT
 import org.apache.kyuubi.operation.{Operation, OperationManager}
 import org.apache.kyuubi.session.Session
@@ -91,5 +92,8 @@ class TrinoOperationManager extends OperationManager("TrinoOperationManager") {
       session: Session,
       catalogName: String,
       schemaName: String,
-      functionName: String): Operation = null
+      functionName: String): Operation = {
+    // TODO: Supports the GetFunctions operation when Trino supports the query of the functions.
+    throw KyuubiSQLException.featureNotSupported()
+  }
 }

externals/kyuubi-trino-engine/src/test/scala/org/apache/kyuubi/engine/trino/operation/TrinoOperationSuite.scala

@@ -33,6 +33,7 @@ import org.apache.hive.service.rpc.thrift.TOpenSessionReq
 import org.apache.hive.service.rpc.thrift.TOperationState
 import org.apache.hive.service.rpc.thrift.TStatusCode
 
+import org.apache.kyuubi.KyuubiSQLException
 import org.apache.kyuubi.config.KyuubiConf.ENGINE_TRINO_CONNECTION_CATALOG
 import org.apache.kyuubi.engine.trino.WithTrinoEngine
 import org.apache.kyuubi.operation.HiveJDBCTestHelper
@@ -557,6 +558,16 @@ class TrinoOperationSuite extends WithTrinoEngine with HiveJDBCTestHelper {
     }
   }
 
+  test("trino - get functions") {
+    withJdbcStatement() { statement =>
+      val exceptionMsg = intercept[Exception](statement.getConnection.getMetaData.getFunctions(
+        null,
+        null,
+        "abs")).getMessage
+      assert(exceptionMsg === KyuubiSQLException.featureNotSupported().getMessage)
+    }
+  }
+
   test("execute statement -  select decimal") {
     withJdbcStatement() { statement =>
       val resultSet = statement.executeQuery("SELECT DECIMAL '1.2' as col1, DECIMAL '1.23' AS col2")