From aca6aae5fd82428c631231c8eccc301b250031d3 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 11 Nov 2020 15:33:48 -0800
Subject: [PATCH] modules/m_room_tombstone: Invalidate alias cache entries for
 effect.

---
 matrix/matrix.cc            |  1 +
 modules/Makefile.am         |  2 ++
 modules/m_room_tombstone.cc | 58 +++++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)
 create mode 100644 modules/m_room_tombstone.cc

diff --git a/matrix/matrix.cc b/matrix/matrix.cc
index c73d7ebf1..7cdc6a77b 100644
--- a/matrix/matrix.cc
+++ b/matrix/matrix.cc
@@ -85,6 +85,7 @@ ircd::m::matrix::module_names
 	"m_room_redaction",
 	"m_room_server_acl",
 	"m_room_third_party_invite",
+	"m_room_tombstone",
 
 	"media_media",
 
diff --git a/modules/Makefile.am b/modules/Makefile.am
index 9311bd076..05699d862 100644
--- a/modules/Makefile.am
+++ b/modules/Makefile.am
@@ -104,6 +104,7 @@ m_room_power_levels_la_SOURCES = m_room_power_levels.cc
 m_room_redaction_la_SOURCES = m_room_redaction.cc
 m_room_server_acl_la_SOURCES = m_room_server_acl.cc
 m_room_third_party_invite_la_SOURCES = m_room_third_party_invite.cc
+m_room_tombstone_la_SOURCES = m_room_tombstone.cc
 
 m_module_LTLIBRARIES = \
 	m_breadcrumbs.la \
@@ -135,6 +136,7 @@ m_module_LTLIBRARIES = \
 	m_room_redaction.la \
 	m_room_server_acl.la \
 	m_room_third_party_invite.la \
+	m_room_tombstone.la \
 	###
 
 ###############################################################################
diff --git a/modules/m_room_tombstone.cc b/modules/m_room_tombstone.cc
new file mode 100644
index 000000000..2d7a7431d
--- /dev/null
+++ b/modules/m_room_tombstone.cc
@@ -0,0 +1,58 @@
+// The Construct
+//
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+namespace ircd::m
+{
+	static void room_tombstone_effect_handler(const event &, vm::eval &);
+	extern hookfn<vm::eval &> room_tombstone_effect_hook;
+}
+
+ircd::mapi::header
+IRCD_MODULE
+{
+	"Matrix m.room.tombstone"
+};
+
+decltype(ircd::m::room_tombstone_effect_hook)
+ircd::m::room_tombstone_effect_hook
+{
+	room_tombstone_effect_handler,
+	{
+		{ "_site",  "vm.effect"        },
+		{ "type",   "m.room.tombstone" },
+	}
+};
+
+void
+ircd::m::room_tombstone_effect_handler(const m::event &event,
+                                       m::vm::eval &)
+{
+	assert(at<"type"_>(event) == "m.room.tombstone");
+
+	const m::room room
+	{
+		at<"room_id"_>(event)
+	};
+
+	if(!creator(room, at<"sender"_>(event)))
+		return;
+
+	const m::room::aliases aliases
+	{
+		room
+	};
+
+	aliases.for_each([](const auto &room_alias)
+	{
+		// Invalidate the alias cache immediately so we don't have to wait a TTL
+		m::room::aliases::cache::del(room_alias);
+		return true;
+	});
+}