Add a Response object

This object will abstract the filter response. For now, it only allow
not to respond. This will change in a future version.

opensmtpd/examples/dummy.rs

@@ -1,17 +1,17 @@
 use env_logger::{Builder, Env};
 use log::{debug, info};
-use opensmtpd::{event, handlers, Entry, SmtpIn};
+use opensmtpd::{event, handlers, Entry, Response, SmtpIn};
 
 #[event(Any)]
-fn on_event(entry: &Entry) -> bool {
+fn on_event(entry: &Entry) -> Response {
     debug!("Event received: {:?}", entry);
-    true
+    Response::None
 }
 
 #[event(LinkConnect)]
-fn on_connect(entry: &Entry) -> bool {
+fn on_connect(entry: &Entry) -> Response {
     info!("New client on session {:x}.", entry.session_id);
-    true
+    Response::None
 }
 
 fn main() {

opensmtpd/src/event_handlers.rs

@@ -1,4 +1,5 @@
 use crate::entry::{Entry, Event};
+use crate::Response;
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum MatchEvent {
@@ -9,7 +10,7 @@ pub enum MatchEvent {
 #[derive(Clone)]
 pub struct EventHandler {
     event: MatchEvent,
-    callback: (fn(&Entry) -> bool),
+    callback: (fn(&Entry) -> Response),
 }
 
 impl EventHandler {
@@ -31,7 +32,7 @@ impl EventHandler {
         MatchEvent::Evt(events)
     }
 
-    pub fn new(event_str: String, callback: (fn(&Entry) -> bool)) -> Self {
+    pub fn new(event_str: String, callback: (fn(&Entry) -> Response)) -> Self {
         EventHandler {
             event: EventHandler::get_events_from_string(&event_str),
             callback,
@@ -45,7 +46,9 @@ impl EventHandler {
         }
     }
 
-    pub fn call(&self, entry: &Entry) -> bool {
+    pub fn call(&self, entry: &Entry) {
-        (self.callback)(entry)
+        match (self.callback)(entry) {
+            Response::None => {}
+        };
     }
 }

opensmtpd/src/lib.rs

@@ -26,6 +26,10 @@ macro_rules! handlers {
     };
 }
 
+pub enum Response {
+    None,
+}
+
 struct SessionHandler {
     entry_rx: mpsc::Receiver<Entry>,
     event_handlers: Vec<EventHandler>,