operprefix + ojoin: server oper prefix (!/mode y, above owner) auto-granted to opers + OJOIN command

src/modules/operprefix.rs

@@ -0,0 +1,79 @@
+//! operprefix — network staff (IRC opers) get a distinct `!` prefix (prefix mode
+//! `y`, ranked above channel owner) in every channel, so users can see who's staff
+//! and ops can't kick/deop them. Enabled with `operprefix = yes`. Also provides the
+//! shared grant/clear primitive used by [`crate::modules::ojoin`].
+
+use crate::module::Module;
+use crate::server::Server;
+use crate::Uid;
+
+pub fn enabled(s: &Server) -> bool {
+    s.conf_bool("operprefix", false)
+}
+
+/// Set/clear the oper prefix for `uid` in one channel and broadcast `MODE ±y`.
+fn set(s: &mut Server, uid: Uid, key: &str, on: bool) {
+    let Some(nick) = s.users.get(&uid).map(|u| u.nick.clone()) else {
+        return;
+    };
+    let changed = match s.channels.get_mut(key).and_then(|c| c.members.get_mut(&uid)) {
+        Some(m) if m.oprefix != on => {
+            m.oprefix = on;
+            true
+        }
+        _ => false,
+    };
+    if !changed {
+        return;
+    }
+    let sign = if on { '+' } else { '-' };
+    let name = s.channels.get(key).map(|c| c.name.clone()).unwrap_or_default();
+    s.to_channel(key, &format!(":{} MODE {name} {sign}y {nick}", s.name), None);
+    s.propagate(&format!(":{} MODE {name} {sign}y {nick}", s.sid), None);
+}
+
+/// Grant the oper prefix in `key` (used by ojoin and on-join auto-grant).
+pub fn grant(s: &mut Server, uid: Uid, key: &str) {
+    set(s, uid, key, true);
+}
+
+fn all_channels(s: &Server, uid: Uid) -> Vec<String> {
+    s.users
+        .get(&uid)
+        .map(|u| u.channels.iter().cloned().collect())
+        .unwrap_or_default()
+}
+
+/// Auto-grant to opers on join when the feature is enabled.
+fn join_grant(s: &mut Server, uid: Uid, key: &str) {
+    if enabled(s) && s.is_oper(uid) {
+        grant(s, uid, key);
+    }
+}
+
+/// Grant across all of `uid`'s channels — on oper-up.
+pub fn grant_all(s: &mut Server, uid: Uid) {
+    if !enabled(s) {
+        return;
+    }
+    for key in all_channels(s, uid) {
+        grant(s, uid, &key);
+    }
+}
+
+/// Clear across all of `uid`'s channels — on de-oper (safe no-op if never granted).
+pub fn clear_all(s: &mut Server, uid: Uid) {
+    for key in all_channels(s, uid) {
+        set(s, uid, &key, false);
+    }
+}
+
+pub struct OperPrefix;
+impl Module for OperPrefix {
+    fn name(&self) -> &'static str {
+        "operprefix"
+    }
+    fn on_join(&mut self, s: &mut Server, uid: Uid, chan: &str) {
+        join_grant(s, uid, &chan.to_ascii_lowercase());
+    }
+}