add: server state struct

src/async_resolver.rs

@@ -5,6 +5,7 @@ pub mod resolver_error;
 pub mod server_info;
 pub mod slist;
 pub mod state_block;
+pub mod server_state;
 
 use self::lookup_response::LookupResponse;
 use crate::async_resolver::resolver_error::ResolverError;

src/async_resolver/server_state.rs

@@ -0,0 +1,35 @@
+use crate::async_resolver::server_info::ServerInfo;
+
+/// Struct that holds the state of the queried server for a single request.
+/// 
+/// A structure which describes the name servers which the resolver is 
+/// currently trying to query. This structure keeps track of the state of a 
+/// request if it must wait for answers from other name servers.
+pub struct ServerState {
+    name_servers: Vec<ServerInfo>,
+    current_server_index: usize,
+}
+
+impl ServerState {
+    /// Creates a new ServerState for a request.
+    /// 
+    /// # Arguments
+    /// * `name_servers` - A vector of ServerInfo structs that represent the name servers to query.
+    /// 
+    /// # Example
+    /// ```
+    /// let server_state = ServerState::new(vec![ServerInfo::new("
+    /// 
+    /// ```
+    pub fn new(name_servers: Vec<ServerInfo>) -> ServerState {
+        ServerState {
+            name_servers: name_servers,
+            current_server_index: 0,
+        }
+    }
+
+    /// Returns a reference to the `name_servers` of the request.
+    pub fn get_name_servers(&self) -> &Vec<ServerInfo> {
+        return &self.name_servers;
+    }
+}