1 files changed, 60 insertions, 0 deletions
diff --git a/comm/chat/protocols/irc/ircMultiPrefix.sys.mjs b/comm/chat/protocols/irc/ircMultiPrefix.sys.mjs
new file mode 100644
index 0000000000..abf9727981
--- /dev/null
+++ b/comm/chat/protocols/irc/ircMultiPrefix.sys.mjs
@@ -0,0 +1,60 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This contains an implementation of the multi-prefix IRC extension. This fixes
+ * a protocol level bug where the following can happen:
+ *   foo MODE +h
+ *   foo MODE +o
+ *   bar JOINs the channel (and receives @foo)
+ *   foo MODE -o
+ * foo knows that it has mode +h, but bar does not know foo has +h set.
+ *
+ *   https://docs.inspircd.org/2/modules/namesx/
+ *   https://ircv3.net/specs/extensions/multi-prefix-3.1
+ */
+
+import { ircHandlerPriorities } from "resource:///modules/ircHandlerPriorities.sys.mjs";
+
+export var isupportNAMESX = {
+  name: "ISUPPORT NAMESX",
+  // Slightly above default ISUPPORT priority.
+  priority: ircHandlerPriorities.DEFAULT_PRIORITY + 10,
+  isEnabled: () => true,
+
+  commands: {
+    NAMESX(aMessage) {
+      this.sendMessage("PROTOCTL", "NAMESX");
+      return true;
+    },
+  },
+};
+
+export var capMultiPrefix = {
+  name: "CAP multi-prefix",
+  // Slightly above default ISUPPORT priority.
+  priority: ircHandlerPriorities.HIGH_PRIORITY,
+  isEnabled: () => true,
+
+  commands: {
+    "multi-prefix": function (aMessage) {
+      // Request to use multi-prefix if it is supported.
+      if (
+        aMessage.cap.subcommand === "LS" ||
+        aMessage.cap.subcommand === "NEW"
+      ) {
+        this.addCAP("multi-prefix");
+        this.sendMessage("CAP", ["REQ", "multi-prefix"]);
+      } else if (
+        aMessage.cap.subcommand === "ACK" ||
+        aMessage.cap.subcommand === "NAK"
+      ) {
+        this.removeCAP("multi-prefix");
+      } else {
+        return false;
+      }
+      return true;
+    },
+  },
+};