From 0fd5514d496d3313634f953a321ffc46f3cc8147 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sat, 18 Feb 2023 10:53:26 -0800
Subject: [PATCH] ircd::m: Add m::member(event) convenience inline interface.

ircd::m::membership: Assertions for event type; optimize branch.
---
 include/ircd/m/m.h          |  1 +
 include/ircd/m/member.h     | 42 +++++++++++++++++++++++++++++++++++++
 include/ircd/m/membership.h |  2 +-
 matrix/membership.cc        | 36 +++++++++++++++++++------------
 4 files changed, 67 insertions(+), 14 deletions(-)
 create mode 100644 include/ircd/m/member.h

diff --git a/include/ircd/m/m.h b/include/ircd/m/m.h
index 7b8a34040..a2fde5c5f 100644
--- a/include/ircd/m/m.h
+++ b/include/ircd/m/m.h
@@ -73,6 +73,7 @@ namespace ircd::m
 #include "rooms_summary.h"
 #include "groups.h"
 #include "membership.h"
+#include "member.h"
 #include "filter.h"
 #include "events.h"
 #include "node.h"
diff --git a/include/ircd/m/member.h b/include/ircd/m/member.h
new file mode 100644
index 000000000..4d272a49b
--- /dev/null
+++ b/include/ircd/m/member.h
@@ -0,0 +1,42 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2023 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.
+
+#pragma once
+#define HAVE_IRCD_M_MEMBER_H
+
+namespace ircd::m
+{
+	bool member(const event &, const string_view &membership);
+	bool member(const event &, const vector_view<const string_view> &);
+}
+
+/// Events that are not type=m.room.member will return false; the rest will be
+/// passed to the analogous m::membership function which does not check type.
+inline bool
+ircd::m::member(const event &event,
+                const vector_view<const string_view> &membership)
+{
+	if(json::get<"type"_>(event) != "m.room.member")
+		return false;
+
+	return m::membership(event, membership);
+}
+
+/// Events that are not type=m.room.member will return false; the rest will be
+/// passed to the analogous m::membership function which does not check type.
+inline bool
+ircd::m::member(const event &event,
+                const string_view &membership)
+{
+	if(json::get<"type"_>(event) != "m.room.member")
+		return false;
+
+	return m::membership(event) == membership;
+}
diff --git a/include/ircd/m/membership.h b/include/ircd/m/membership.h
index 2bbfb8155..92d7fdc7e 100644
--- a/include/ircd/m/membership.h
+++ b/include/ircd/m/membership.h
@@ -14,7 +14,7 @@
 namespace ircd::m
 {
 	// Extract membership string from event data.
-	string_view membership(const event &);
+	[[gnu::pure]] string_view membership(const event &);
 
 	// Query and copy membership string to buffer. Note that the event type
 	// is not checked here, only content.membership is sought.
diff --git a/matrix/membership.cc b/matrix/membership.cc
index 4babaa244..bbafdd10d 100644
--- a/matrix/membership.cc
+++ b/matrix/membership.cc
@@ -82,9 +82,14 @@ bool
 ircd::m::membership(const m::event &event,
                     const vector_view<const string_view> &membership)
 {
+	const auto matching
+	{
+		m::membership(event)
+	};
+
 	const auto it
 	{
-		std::find(begin(membership), end(membership), m::membership(event))
+		std::find(begin(membership), end(membership), matching)
 	};
 
 	return it != end(membership);
@@ -125,23 +130,28 @@ ircd::m::membership(const mutable_buffer &out,
 ircd::string_view
 ircd::m::membership(const event &event)
 {
-	const json::object &content
-	{
-		json::get<"content"_>(event)
-	};
+	// The caller should check event type; empty is allowed if they only have content.
+	assert(!json::get<"type"_>(event) || json::get<"type"_>(event) == "m.room.member");
 
-	const string_view &membership
+	const auto &membership
 	{
 		json::get<"membership"_>(event)
 	};
 
-	if(membership)
-		return membership;
-
-	const json::string &content_membership
+	if(likely(!membership))
 	{
-		content.get("membership")
-	};
+		const auto &content
+		{
+			json::get<"content"_>(event)
+		};
 
-	return content_membership;
+		const json::string &membership
+		{
+			content.get("membership")
+		};
+
+		return membership;
+	}
+
+	return membership;
 }