ircd:Ⓜ️:room: Add type iteration interface.

include/ircd/m/room/room.h

@@ -114,6 +114,7 @@ struct ircd::m::room
 	struct state;
 	struct members;
 	struct origins;
+	struct type;
 	struct head;
 	struct auth;
 	struct power;
@@ -190,6 +191,7 @@ struct ircd::m::room
 #include "state_history.h"
 #include "members.h"
 #include "origins.h"
+#include "type.h"
 #include "head.h"
 #include "auth.h"
 #include "power.h"

include/ircd/m/room/type.h

@@ -0,0 +1,49 @@
+// 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.
+
+#pragma once
+#define HAVE_IRCD_M_ROOM_TYPE_H
+
+/// Interface to all room events sorted by type. This is not the "room type"
+/// or m::type(room) classification string. This is an interface to the
+/// _room_type table allowing efficient iteration of events similar to
+/// room::events (_room_events) for a single event type. Events are sorted
+/// by descending depth and event_idx within each type (similar to
+/// room::events).
+///
+struct ircd::m::room::type
+{
+	using closure = std::function<bool (const string_view &, const uint64_t &, const event::idx &)>;
+
+	m::room room;
+	string_view _type;
+	std::pair<uint64_t, int64_t> range; // highest (inclusive) to lowest (exclusive)
+
+  public:
+	bool for_each(const closure &) const;
+	size_t count() const;
+	bool empty() const;
+
+	type(const m::room &,
+	     const string_view &type  = {},
+	     const decltype(range) &  = { -1UL, -1L });
+
+	static bool prefetch(const room::id &, const string_view &type, const int64_t &depth);
+	static bool prefetch(const room::id &, const string_view &type);
+};
+
+inline
+ircd::m::room::type::type(const m::room &room,
+                          const string_view &type,
+                          const decltype(range) &range)
+:room{room}
+,_type{type}
+,range{range}
+{}

matrix/Makefile.am

@@ -83,6 +83,7 @@ libircd_matrix_la_SOURCES += room_leave.cc
 libircd_matrix_la_SOURCES += room_visible.cc
 libircd_matrix_la_SOURCES += room_members.cc
 libircd_matrix_la_SOURCES += room_origins.cc
+libircd_matrix_la_SOURCES += room_type.cc
 libircd_matrix_la_SOURCES += room_power.cc
 libircd_matrix_la_SOURCES += room_state.cc
 libircd_matrix_la_SOURCES += room_state_history.cc

matrix/room_type.cc

@@ -0,0 +1,91 @@
+// The Construct
+//
+// Copyright (C) Matrix 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.
+
+bool
+ircd::m::room::type::prefetch(const room::id &room_id,
+                              const string_view &type)
+{
+	return prefetch(room_id, type, -1L);
+}
+
+bool
+ircd::m::room::type::prefetch(const room::id &room_id,
+                              const string_view &type,
+                              const int64_t &depth)
+{
+	char buf[dbs::ROOM_TYPE_KEY_MAX_SIZE];
+	const string_view &key
+	{
+		dbs::room_type_key(buf, room_id, type, depth, -1L)
+	};
+
+	return db::prefetch(dbs::room_type, key);
+}
+
+bool
+ircd::m::room::type::empty()
+const
+{
+	return for_each([]
+	(const auto &type, const auto &depth, const auto &event_idx)
+	{
+		return false;
+	});
+}
+
+size_t
+ircd::m::room::type::count()
+const
+{
+	size_t ret(0);
+	for_each([&ret]
+	(const auto &type, const auto &depth, const auto &event_idx)
+	{
+		++ret;
+		return true;
+	});
+
+	return ret;
+}
+
+bool
+ircd::m::room::type::for_each(const closure &closure)
+const
+{
+	char buf[dbs::ROOM_TYPE_KEY_MAX_SIZE];
+	const string_view &key
+	{
+		dbs::room_type_key(buf, room.room_id, _type, range.first, -1UL)
+	};
+
+	auto it
+	{
+		dbs::room_type.begin(key)
+	};
+
+	for(; it; ++it)
+	{
+		const auto &[_type, depth, event_idx]
+		{
+			dbs::room_type_key(it->first)
+		};
+
+		if(this->_type && this->_type != _type)
+			break;
+
+		if(int64_t(depth) <= range.second)
+			break;
+
+		if(!closure(_type, depth, event_idx))
+			return false;
+	}
+
+	return true;
+}