refactor: Move minor map functions in MapFunctions.h

Summary: We have simple map functions (map_key_exists, map_remove_null_values), which does not required independent files. Moving into MapFunctions.h.

Differential Revision: D70495645

Author: amitkdutta

velox/functions/prestosql/MapFunctions.h

@@ -32,4 +32,21 @@ struct MapKeyExists {
   }
 };
 
+template <typename TExec>
+struct MapRemoveNullValues {
+  VELOX_DEFINE_FUNCTION_TYPES(TExec);
+
+  void call(
+      out_type<Map<Generic<T1>, Generic<T2>>>& out,
+      const arg_type<Map<Generic<T1>, Generic<T2>>>& inputMap) {
+    for (const auto& entry : inputMap) {
+      if (entry.second.has_value()) {
+        auto [keyWriter, valueWriter] = out.add_item();
+        keyWriter.copy_from(entry.first);
+        valueWriter.copy_from(entry.second.value());
+      }
+    }
+  }
+};
+
 } // namespace facebook::velox::functions

velox/functions/prestosql/MapRemoveNullValues.h

@@ -21,7 +21,6 @@
 #include "velox/functions/prestosql/MapFunctions.h"
 #include "velox/functions/prestosql/MapKeysByTopNValues.h"
 #include "velox/functions/prestosql/MapNormalize.h"
-#include "velox/functions/prestosql/MapRemoveNullValues.h"
 #include "velox/functions/prestosql/MapSubset.h"
 #include "velox/functions/prestosql/MapTopN.h"
 #include "velox/functions/prestosql/MapTopNKeys.h"