dendrite/roomserver/internal/input_membership.go

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// Copyright 2017 Vector Creations Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package internal
import (
"context"
"fmt"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/storage"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
)
// updateMembership updates the current membership and the invites for each
// user affected by a change in the current state of the room.
// Returns a list of output events to write to the kafka log to inform the
// consumers about the invites added or retired by the change in current state.
func updateMemberships(
ctx context.Context,
db storage.Database,
updater types.RoomRecentEventsUpdater,
removed, added []types.StateEntry,
) ([]api.OutputEvent, error) {
changes := membershipChanges(removed, added)
var eventNIDs []types.EventNID
for _, change := range changes {
if change.addedEventNID != 0 {
eventNIDs = append(eventNIDs, change.addedEventNID)
}
if change.removedEventNID != 0 {
eventNIDs = append(eventNIDs, change.removedEventNID)
}
}
// Load the event JSON so we can look up the "membership" key.
// TODO: Maybe add a membership key to the events table so we can load that
// key without having to load the entire event JSON?
events, err := db.Events(ctx, eventNIDs)
if err != nil {
return nil, err
}
var updates []api.OutputEvent
for _, change := range changes {
var ae *gomatrixserverlib.Event
var re *gomatrixserverlib.Event
targetUserNID := change.EventStateKeyNID
if change.removedEventNID != 0 {
ev, _ := eventMap(events).lookup(change.removedEventNID)
if ev != nil {
re = &ev.Event
}
}
if change.addedEventNID != 0 {
ev, _ := eventMap(events).lookup(change.addedEventNID)
if ev != nil {
ae = &ev.Event
}
}
if updates, err = updateMembership(updater, targetUserNID, re, ae, updates); err != nil {
return nil, err
}
}
return updates, nil
}
func updateMembership(
updater types.RoomRecentEventsUpdater, targetUserNID types.EventStateKeyNID,
remove, add *gomatrixserverlib.Event,
updates []api.OutputEvent,
) ([]api.OutputEvent, error) {
var err error
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// Default the membership to Leave if no event was added or removed.
oldMembership := gomatrixserverlib.Leave
newMembership := gomatrixserverlib.Leave
if remove != nil {
oldMembership, err = remove.Membership()
if err != nil {
return nil, err
}
}
if add != nil {
newMembership, err = add.Membership()
if err != nil {
return nil, err
}
}
if oldMembership == newMembership && newMembership != gomatrixserverlib.Join {
// If the membership is the same then nothing changed and we can return
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// immediately, unless it's a Join update (e.g. profile update).
return updates, nil
}
mu, err := updater.MembershipUpdater(targetUserNID)
if err != nil {
return nil, err
}
switch newMembership {
case gomatrixserverlib.Invite:
return updateToInviteMembership(mu, add, updates, updater.RoomVersion())
case gomatrixserverlib.Join:
return updateToJoinMembership(mu, add, updates)
case gomatrixserverlib.Leave, gomatrixserverlib.Ban:
return updateToLeaveMembership(mu, add, newMembership, updates)
default:
panic(fmt.Errorf(
"input: membership %q is not one of the allowed values", newMembership,
))
}
}
func updateToInviteMembership(
mu types.MembershipUpdater, add *gomatrixserverlib.Event, updates []api.OutputEvent,
roomVersion gomatrixserverlib.RoomVersion,
) ([]api.OutputEvent, error) {
// We may have already sent the invite to the user, either because we are
// reprocessing this event, or because the we received this invite from a
// remote server via the federation invite API. In those cases we don't need
// to send the event.
needsSending, err := mu.SetToInvite(*add)
if err != nil {
return nil, err
}
if needsSending {
// We notify the consumers using a special event even though we will
// notify them about the change in current state as part of the normal
// room event stream. This ensures that the consumers only have to
// consider a single stream of events when determining whether a user
// is invited, rather than having to combine multiple streams themselves.
onie := api.OutputNewInviteEvent{
Event: add.Headered(roomVersion),
RoomVersion: roomVersion,
}
updates = append(updates, api.OutputEvent{
Type: api.OutputTypeNewInviteEvent,
NewInviteEvent: &onie,
})
}
return updates, nil
}
func updateToJoinMembership(
mu types.MembershipUpdater, add *gomatrixserverlib.Event, updates []api.OutputEvent,
) ([]api.OutputEvent, error) {
// If the user is already marked as being joined, we call SetToJoin to update
// the event ID then we can return immediately. Retired is ignored as there
// is no invite event to retire.
if mu.IsJoin() {
_, err := mu.SetToJoin(add.Sender(), add.EventID(), true)
if err != nil {
return nil, err
}
return updates, nil
}
// When we mark a user as being joined we will invalidate any invites that
// are active for that user. We notify the consumers that the invites have
// been retired using a special event, even though they could infer this
// by studying the state changes in the room event stream.
retired, err := mu.SetToJoin(add.Sender(), add.EventID(), false)
if err != nil {
return nil, err
}
for _, eventID := range retired {
orie := api.OutputRetireInviteEvent{
EventID: eventID,
Membership: gomatrixserverlib.Join,
RetiredByEventID: add.EventID(),
TargetUserID: *add.StateKey(),
}
updates = append(updates, api.OutputEvent{
Type: api.OutputTypeRetireInviteEvent,
RetireInviteEvent: &orie,
})
}
return updates, nil
}
func updateToLeaveMembership(
mu types.MembershipUpdater, add *gomatrixserverlib.Event,
newMembership string, updates []api.OutputEvent,
) ([]api.OutputEvent, error) {
// If the user is already neither joined, nor invited to the room then we
// can return immediately.
if mu.IsLeave() {
return updates, nil
}
// When we mark a user as having left we will invalidate any invites that
// are active for that user. We notify the consumers that the invites have
// been retired using a special event, even though they could infer this
// by studying the state changes in the room event stream.
retired, err := mu.SetToLeave(add.Sender(), add.EventID())
if err != nil {
return nil, err
}
for _, eventID := range retired {
orie := api.OutputRetireInviteEvent{
EventID: eventID,
Membership: newMembership,
RetiredByEventID: add.EventID(),
TargetUserID: *add.StateKey(),
}
updates = append(updates, api.OutputEvent{
Type: api.OutputTypeRetireInviteEvent,
RetireInviteEvent: &orie,
})
}
return updates, nil
}
// membershipChanges pairs up the membership state changes from a sorted list
// of state removed and a sorted list of state added.
func membershipChanges(removed, added []types.StateEntry) []stateChange {
changes := pairUpChanges(removed, added)
var result []stateChange
for _, c := range changes {
if c.EventTypeNID == types.MRoomMemberNID {
result = append(result, c)
}
}
return result
}
type stateChange struct {
types.StateKeyTuple
removedEventNID types.EventNID
addedEventNID types.EventNID
}
// pairUpChanges pairs up the state events added and removed for each type,
// state key tuple. Assumes that removed and added are sorted.
func pairUpChanges(removed, added []types.StateEntry) []stateChange {
var ai int
var ri int
var result []stateChange
for {
switch {
case ai == len(added):
// We've reached the end of the added entries.
// The rest of the removed list are events that were removed without
// an event with the same state key being added.
for _, s := range removed[ri:] {
result = append(result, stateChange{
StateKeyTuple: s.StateKeyTuple,
removedEventNID: s.EventNID,
})
}
return result
case ri == len(removed):
// We've reached the end of the removed entries.
// The rest of the added list are events that were added without
// an event with the same state key being removed.
for _, s := range added[ai:] {
result = append(result, stateChange{
StateKeyTuple: s.StateKeyTuple,
addedEventNID: s.EventNID,
})
}
return result
case added[ai].StateKeyTuple == removed[ri].StateKeyTuple:
// The tuple is in both lists so an event with that key is being
// removed and another event with the same key is being added.
result = append(result, stateChange{
StateKeyTuple: added[ai].StateKeyTuple,
removedEventNID: removed[ri].EventNID,
addedEventNID: added[ai].EventNID,
})
ai++
ri++
case added[ai].StateKeyTuple.LessThan(removed[ri].StateKeyTuple):
// The lists are sorted so the added entry being less than the
// removed entry means that the added event was added without an
// event with the same key being removed.
result = append(result, stateChange{
StateKeyTuple: added[ai].StateKeyTuple,
addedEventNID: added[ai].EventNID,
})
ai++
default:
// Reaching the default case implies that the removed entry is less
// than the added entry. Since the lists are sorted this means that
// the removed event was removed without an event with the same
// key being added.
result = append(result, stateChange{
StateKeyTuple: removed[ai].StateKeyTuple,
removedEventNID: removed[ri].EventNID,
})
ri++
}
}
}