1 files changed, 41 insertions, 0 deletions
diff --git a/comm/chat/protocols/irc/ircEchoMessage.sys.mjs b/comm/chat/protocols/irc/ircEchoMessage.sys.mjs
new file mode 100644
index 0000000000..24a27be902
--- /dev/null
+++ b/comm/chat/protocols/irc/ircEchoMessage.sys.mjs
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+/* 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 implements the echo-message capability for IRC.
+ *   https://ircv3.net/specs/extensions/echo-message-3.2
+ *
+ * When enabled, displaying of a sent messages is disabled (until it is received
+ * by the server and sent back to the sender). This helps to ensure the ordering
+ * of messages is consistent for all participants in a channel and also helps
+ * signify whether a message was properly sent to a channel during disconnect.
+ */
+
+import { ircHandlerPriorities } from "resource:///modules/ircHandlerPriorities.sys.mjs";
+
+export var capEchoMessage = {
+  name: "echo-message CAP",
+  priority: ircHandlerPriorities.DEFAULT_PRIORITY,
+  isEnabled: () => true,
+
+  commands: {
+    "echo-message": function (aMessage) {
+      if (
+        aMessage.cap.subcommand === "LS" ||
+        aMessage.cap.subcommand === "NEW"
+      ) {
+        this.addCAP("echo-message");
+        this.sendMessage("CAP", ["REQ", "echo-message"]);
+      } else if (
+        aMessage.cap.subcommand === "ACK" ||
+        aMessage.cap.subcommand === "NAK"
+      ) {
+        this.removeCAP("echo-message");
+      } else {
+        return false;
+      }
+      return true;
+    },
+  },
+};