metadata: Add metadata factory and implementation for integer types

Co-authored-by: Thomas Egerer <[email protected]>

src/libstrongswan/metadata/metadata_factory.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2021 Tobias Brunner, codelabs GmbH
+ * Copyright (C) 2021 Thomas Egerer, secunet AG
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ * @defgroup metadata_factory metadata_factory
+ * @{ @ingroup metadata
+ */
+
+#ifndef METADATA_FACTORY_H_
+#define METADATA_FACTORY_H_
+
+#include "metadata.h"
+
+typedef struct metadata_factory_t metadata_factory_t;
+
+/**
+ * Create a factory for dealing with metadata objects.
+ */
+struct metadata_factory_t {
+
+	/**
+	 * Create a metadata object of the given type.
+	 *
+	 * @param type		type of the desired metadata object
+	 * @param ...		data to wrap into the metadata object
+	 * @return			metadata handler on success, NULL otherwise
+	 */
+	metadata_t *(*create)(metadata_factory_t *this, const char *type, ...);
+
+	/**
+	 * Register a constructor for a given type.
+	 *
+	 * @param type		type to register
+	 * @param create	metadata constructor
+	 */
+	void (*register_type)(metadata_factory_t *this, const char *type,
+						  metadata_create_t create);
+
+	/**
+	 * Destroy a metadata_factory_t instance.
+	 */
+	void (*destroy)(metadata_factory_t *this);
+};
+
+/**
+ * Create a metadata_factory_t instance.
+ */
+metadata_factory_t *metadata_factory_create();
+
+#endif /** METADATA_FACTORY_H_ @}*/