From ed5af1fdbdd7aca5f9e9379a87d2fb125fcd46ea Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 26 Jun 2019 04:15:56 -0700
Subject: [PATCH] ircd::m::id: Add class representations for event::v3 and
 event::v4.

---
 include/ircd/m/id.h | 21 +++++++++++++
 ircd/m_id.cc        | 73 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+)

diff --git a/include/ircd/m/id.h b/include/ircd/m/id.h
index cf2ab6793..c29efe317 100644
--- a/include/ircd/m/id.h
+++ b/include/ircd/m/id.h
@@ -157,6 +157,9 @@ struct ircd::m::id::user
 struct ircd::m::id::event
 :ircd::m::id
 {
+	struct v3;
+	struct v4;
+
 	using buf = m::id::buf<event>;
 	using closure = std::function<void (const id::event &)>;
 	using closure_bool = std::function<bool (const id::event &)>;
@@ -171,6 +174,24 @@ struct ircd::m::id::event
 	event() = default;
 };
 
+/// Version 3 event_id
+struct ircd::m::id::event::v3
+:ircd::m::id::event
+{
+	v3(const mutable_buffer &out, const json::object &);
+	v3(const string_view &id);
+	v3() = default;
+};
+
+/// Version 4 event_id
+struct ircd::m::id::event::v4
+:ircd::m::id::event
+{
+	v4(const mutable_buffer &out, const json::object &);
+	v4(const string_view &id);
+	v4() = default;
+};
+
 /// (Appendix 4.2.2) Room IDs and Event IDs
 ///
 /// A room has exactly one room ID. A room ID has the format:
diff --git a/ircd/m_id.cc b/ircd/m_id.cc
index 8f238cd49..56d156a5d 100644
--- a/ircd/m_id.cc
+++ b/ircd/m_id.cc
@@ -675,6 +675,79 @@ const
 		                               "1";
 }
 
+//
+// id::event::v3
+//
+
+ircd::m::id::event::v3::v3(const string_view &id)
+:id::event{id}
+{
+	if(unlikely(version() != "3"))
+		throw m::INVALID_MXID
+		{
+			"Not a version 3 event mxid"
+		};
+}
+
+ircd::m::id::event::v3::v3(const mutable_buffer &out,
+                           const json::object &event)
+:v3{[&out, event]
+{
+	if(unlikely(buffer::size(out) < 44))
+		throw std::out_of_range
+		{
+			"Output buffer insufficient for v3 event_id"
+		};
+
+	const sha256::buf hash
+	{
+		sha256{event}
+	};
+
+	out[0] = '$';
+	return b64encode_unpadded(out + 1, hash);
+}()}
+{
+}
+
+//
+// id::event::v4
+//
+
+ircd::m::id::event::v4::v4(const string_view &id)
+:id::event{id}
+{
+	if(unlikely(version() != "4"))
+		throw m::INVALID_MXID
+		{
+			"Not a version 4 event mxid"
+		};
+}
+
+ircd::m::id::event::v4::v4(const mutable_buffer &out,
+                           const json::object &event)
+:v4{[&out, event]
+{
+	if(unlikely(buffer::size(out) < 44))
+		throw std::out_of_range
+		{
+			"Output buffer insufficient for v4 event_id"
+		};
+
+	const sha256::buf hash
+	{
+		sha256{event}
+	};
+
+	out[0] = '$';
+	string_view ret;
+	ret = b64encode_unpadded(out + 1, hash);
+	ret = b64tob64url(out + 1, ret);
+	return ret;
+}()}
+{
+}
+
 //
 // util
 //