From eb603c22c143f1c1e59a954084af1903d4eb3184 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 11 Jun 2018 23:11:28 -0700
Subject: [PATCH] modules: Add preliminary m_room_aliases protocol suite.

---
 modules/Makefile.am       |   2 +
 modules/m_room_aliases.cc | 108 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 modules/m_room_aliases.cc

diff --git a/modules/Makefile.am b/modules/Makefile.am
index 50fa90046..2bb005fb1 100644
--- a/modules/Makefile.am
+++ b/modules/Makefile.am
@@ -90,6 +90,7 @@ m_room_member_la_SOURCES = m_room_member.cc
 m_room_join_rules_la_SOURCES = m_room_join_rules.cc
 m_room_history_visibility_la_SOURCES = m_room_history_visibility.cc
 m_room_canonical_alias_la_SOURCES = m_room_canonical_alias.cc
+m_room_aliases_la_SOURCES = m_room_aliases.cc
 
 m_module_LTLIBRARIES = \
 	m_noop.la \
@@ -102,6 +103,7 @@ m_module_LTLIBRARIES = \
 	m_room_join_rules.la \
 	m_room_history_visibility.la \
 	m_room_canonical_alias.la \
+	m_room_aliases.la \
 	###
 
 ###############################################################################
diff --git a/modules/m_room_aliases.cc b/modules/m_room_aliases.cc
new file mode 100644
index 000000000..b6d230c7f
--- /dev/null
+++ b/modules/m_room_aliases.cc
@@ -0,0 +1,108 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2018 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.
+
+using namespace ircd;
+
+mapi::header
+IRCD_MODULE
+{
+	"Matrix m.room.aliases"
+};
+
+const m::room::id::buf
+alias_room_id
+{
+	"alias", ircd::my_host()
+};
+
+const m::room
+alias_room
+{
+	alias_room_id
+};
+
+void
+_changed_aliases(const m::event &event)
+{
+	const m::room::id &room_id
+	{
+		at<"room_id"_>(event)
+	};
+
+	const json::array &aliases
+	{
+		at<"content"_>(event).get("aliases")
+	};
+
+	for(const json::string &alias_ : aliases)
+	{
+		const m::room::alias &alias{alias_};
+		const auto event_id
+		{
+			send(alias_room, m::me.user_id, "ircd.alias", alias, json::strung{event})
+		};
+
+		log::info
+		{
+			"Updated aliases of %s by %s in %s [%s] => %s",
+			string_view{room_id},
+			json::get<"sender"_>(event),
+			json::get<"event_id"_>(event),
+			string_view{alias},
+			string_view{event_id}
+		};
+	}
+}
+
+const m::hookfn<>
+_changed_aliases_hookfn
+{
+	_changed_aliases,
+	{
+		{ "_site",    "vm.notify"       },
+		{ "type",     "m.room.aliases"  },
+	}
+};
+
+void
+_can_change_aliases(const m::event &event)
+{
+	const m::room::id &room_id
+	{
+		at<"room_id"_>(event)
+	};
+
+	const json::array &aliases
+	{
+		at<"content"_>(event).get("aliases")
+	};
+
+	for(const json::string &alias_ : aliases)
+	{
+		const m::room::alias &alias{alias_};
+		if(at<"origin"_>(event) != alias.host())
+			throw m::ACCESS_DENIED
+			{
+				"Cannot set alias for host '%s' from origin '%s'",
+				alias.host(),
+				at<"origin"_>(event)
+			};
+	}
+}
+
+const m::hookfn<>
+_can_change_aliases_hookfn
+{
+	_can_change_aliases,
+	{
+		{ "_site",    "vm.eval"         },
+		{ "type",     "m.room.aliases"  },
+	}
+};