Add CPLJSONDocument::SetRoot()

gdal/port/cpl_json.cpp

@@ -146,6 +146,19 @@ CPLJSONObject CPLJSONDocument::GetRoot()
     }
 }
 
+/**
+ * Set json document root object
+ * @param oRoot CPLJSONObject root object
+ *
+ * @since GDAL 3.4
+ */
+void CPLJSONDocument::SetRoot(const CPLJSONObject& oRoot)
+{
+    if( m_poRootJsonObject )
+        json_object_put( TO_JSONOBJ(m_poRootJsonObject) );
+    m_poRootJsonObject = json_object_get( TO_JSONOBJ(oRoot.m_poJsonObject) );
+}
+
 /**
  * Load json document from file by provided path
  * @param  osPath Path to json file.

gdal/port/cpl_json.h

@@ -223,6 +223,7 @@ class CPL_DLL CPLJSONDocument
 
     CPLJSONObject GetRoot();
     const CPLJSONObject GetRoot() const;
+    void SetRoot(const CPLJSONObject& oRoot);
     bool Load(const std::string &osPath);
     bool LoadMemory(const std::string &osStr);
     bool LoadMemory(const GByte *pabyData, int nLength = -1);