construct/include/ircd/m/membership.h

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 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_MEMBERSHIP_H

namespace ircd::m
{
	// Extract membership string from event data.
	[[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.
	string_view membership(const mutable_buffer &out, const event::idx &);

	// Query and copy membership string to buffer; queries room state. (also room.h)
	string_view membership(const mutable_buffer &out, const room &, const id::user &);

	// Query and compare membership string to argument string. Returns true on
	// equal; false on not equal; false on not found. Note in addition to this
	// we allow the user to pass an empty membership string which will test for
	// non-membership as well and return true.
	bool membership(const event::idx &, const string_view &);

	// Query and compare membership string; queries room state. (also room.h)
	// also see overload notes.
	bool membership(const room &, const id::user &, const string_view &);

	// Convenience suite with optimal aggregate queries; if the membership
	// is equal to any of the strings (including the non-membership empty
	// string described above) these functions return true. An empty vector is
	// also a non-membership query.
	bool membership(const event &, const vector_view<const string_view> &);
	bool membership(const event::idx &, const vector_view<const string_view> &);
	bool membership(const room &, const id::user &, const vector_view<const string_view> &);

	// Prefetch suite
	bool membership_prefetch(const event::idx &);
	bool membership_prefetch(const room::state &, const id::user &);

	// Convenience definitions of membership states for atomic queries.
	extern const std::initializer_list<const string_view>
	membership_positive, // join, invite
	membership_negative; // leave, ban, knock, [non-membership]
}

inline bool
ircd::m::membership_prefetch(const room::state &state,
                             const user::id &user_id)
{
	if(state.prefetch("m.room.member", user_id))
		return true;

	// The above prefetch didn't launch; this query is cached.
	const auto event_idx
	{
		state.get(std::nothrow, "m.room.member", user_id)
	};

	return membership_prefetch(event_idx);
}

inline bool
ircd::m::membership_prefetch(const event::idx &event_idx)
{
	return m::prefetch(event_idx, "content");
}

inline bool
ircd::m::membership(const room &room,
                    const id::user &user_id,
                    const string_view &membership)
{
	const vector_view<const string_view> memberships
	{
		std::addressof(membership), 1
	};

	return m::membership(room, user_id, memberships);
}

inline bool
ircd::m::membership(const event::idx &event_idx,
                    const string_view &membership)
{
	const vector_view<const string_view> memberships
	{
		std::addressof(membership), 1
	};

	return m::membership(event_idx, memberships);
}