add document destroy hook

include/libfyaml.h

@@ -4758,6 +4758,76 @@ void
 fy_document_unregister_meta(struct fy_document *fyd)
 	FY_EXPORT;
 
+/**
+ * fy_document_get_userdata() - Get the userdata pointer of a document
+ *
+ * Return the userdata pointer of a document.
+ *
+ * @fyn: The document to get userdata from
+ *
+ * Returns:
+ * The stored userdata pointer
+ */
+void *
+fy_document_get_userdata(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_set_userdata() - Set the userdata pointer of a document
+ *
+ * Set the userdata pointer of a document. If @userdata is NULL
+ * then clear the userdata.
+ *
+ * @fyd: The document to set userdata
+ * @userdata: The userdata pointer
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_set_userdata(struct fy_document *fyd, void *userdata)
+	FY_EXPORT;
+
+/**
+ * typedef fy_document_on_destroy_fn - Userdata clear method
+ *
+ * This is the callback called just before document is destroyed.
+ *
+ * @fyd: The document which will be destroyed
+ * @userdata: The userdata pointer of a document
+ *
+ */
+typedef void (*fy_document_on_destroy_fn)(struct fy_document *fyd, void *userdata);
+
+/**
+ * fy_document_register_on_destroy() - Register an on_destroy hook
+ *
+ * Register an on_destroy hook, to be called when
+ * the document is freed via a final call to fy_document_destroy().
+ *
+ * @fyd: The document which the hook is registered to
+ * @on_destroy_fn: The on_destroy hook method
+ *
+ * Returns:
+ * 0 on success, -1 if another hook is already registered.
+ */
+int
+fy_document_register_on_destroy(struct fy_document *fyd,
+				fy_document_on_destroy_fn on_destroy_fn)
+	FY_EXPORT;
+
+/**
+ * fy_document_unregister_on_destroy() - Unregister an on_destroy hook
+ *
+ * Unregister the currently active on_destroy hook.
+ *
+ * @fyd: The document to unregister it's on_destroy hook.
+ */
+void
+fy_document_unregister_on_destroy(struct fy_document *fyd)
+	FY_EXPORT;
+
+
 /**
  * fy_node_set_marker() - Set a marker of a node
  *

src/lib/fy-doc.c

@@ -380,6 +380,9 @@ void fy_parse_document_destroy(struct fy_parser *fyp, struct fy_document *fyd)
 
 	fy_diag_unref(fyd->diag);
 
+	if (fyd->on_destroy_fn)
+		fyd->on_destroy_fn(fyd, fyd->userdata);
+
 	free(fyd);
 }
 
@@ -6285,6 +6288,40 @@ void fy_document_unregister_meta(struct fy_document *fyd)
 	fyd->meta_user = NULL;
 }
 
+int fy_document_set_userdata(struct fy_document *fyd, void *userdata)
+{
+	if (!fyd || !userdata)
+		return -1;
+
+	fyd->userdata = userdata;
+
+	return 0;
+}
+
+void* fy_document_get_userdata(struct fy_document *fyd)
+{
+	return fyd->userdata;
+}
+
+int fy_document_register_on_destroy(struct fy_document *fyd,
+				    fy_document_on_destroy_fn on_destroy_fn)
+{
+	if (!fyd || !on_destroy_fn)
+		return -1;
+
+	fyd->on_destroy_fn = on_destroy_fn;
+
+	return 0;
+}
+
+void fy_document_unregister_on_destroy(struct fy_document *fyd)
+{
+	if (!fyd)
+		return;
+
+	fyd->on_destroy_fn = NULL;
+}
+
 bool fy_node_set_marker(struct fy_node *fyn, unsigned int marker)
 {
 	unsigned int prev_marks;

src/lib/fy-doc.h

@@ -118,6 +118,9 @@ struct fy_document {
 	fy_node_meta_clear_fn meta_clear_fn;
 	void *meta_user;
 
+	fy_document_on_destroy_fn on_destroy_fn;
+	void *userdata;
+
 	struct fy_path_expr_document_data *pxdd;
 };
 /* only the list declaration/methods */