dendrite/syncapi/storage/syncserver.go
Alex Chen 3e1abe9ad3 Fix /sync may contain duplicate EDUs and EDUs for left rooms (#752)
In 29841be (#718), EDUs are added to /sync responses for rooms listed
in joinedRoomIDs returned by addPDUDeltaToResponse. However this list
may contain rooms other than those currently joined.

Some variable renamings are done to make golangci-lint pass.

Signed-off-by: Alex Chen minecnly@gmail.com
2019-07-31 14:20:11 +01:00

861 lines
29 KiB
Go

// 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 storage
import (
"context"
"database/sql"
"encoding/json"
"fmt"
"strconv"
"time"
"github.com/sirupsen/logrus"
"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
"github.com/matrix-org/dendrite/roomserver/api"
// Import the postgres database driver.
_ "github.com/lib/pq"
"github.com/matrix-org/dendrite/common"
"github.com/matrix-org/dendrite/syncapi/types"
"github.com/matrix-org/dendrite/typingserver/cache"
"github.com/matrix-org/gomatrixserverlib"
)
const (
membershipJoin = "join"
membershipLeave = "leave"
membershipBan = "ban"
)
type stateDelta struct {
roomID string
stateEvents []gomatrixserverlib.Event
membership string
// The PDU stream position of the latest membership event for this user, if applicable.
// Can be 0 if there is no membership event in this delta.
membershipPos int64
}
// Same as gomatrixserverlib.Event but also has the PDU stream position for this event.
type streamEvent struct {
gomatrixserverlib.Event
streamPosition int64
transactionID *api.TransactionID
}
// SyncServerDatabase represents a sync server datasource which manages
// both the database for PDUs and caches for EDUs.
type SyncServerDatasource struct {
db *sql.DB
common.PartitionOffsetStatements
accountData accountDataStatements
events outputRoomEventsStatements
roomstate currentRoomStateStatements
invites inviteEventsStatements
typingCache *cache.TypingCache
}
// NewSyncServerDatabase creates a new sync server database
func NewSyncServerDatasource(dbDataSourceName string) (*SyncServerDatasource, error) {
var d SyncServerDatasource
var err error
if d.db, err = sql.Open("postgres", dbDataSourceName); err != nil {
return nil, err
}
if err = d.PartitionOffsetStatements.Prepare(d.db, "syncapi"); err != nil {
return nil, err
}
if err = d.accountData.prepare(d.db); err != nil {
return nil, err
}
if err = d.events.prepare(d.db); err != nil {
return nil, err
}
if err := d.roomstate.prepare(d.db); err != nil {
return nil, err
}
if err := d.invites.prepare(d.db); err != nil {
return nil, err
}
d.typingCache = cache.NewTypingCache()
return &d, nil
}
// AllJoinedUsersInRooms returns a map of room ID to a list of all joined user IDs.
func (d *SyncServerDatasource) AllJoinedUsersInRooms(ctx context.Context) (map[string][]string, error) {
return d.roomstate.selectJoinedUsers(ctx)
}
// Events lookups a list of event by their event ID.
// Returns a list of events matching the requested IDs found in the database.
// If an event is not found in the database then it will be omitted from the list.
// Returns an error if there was a problem talking with the database.
// Does not include any transaction IDs in the returned events.
func (d *SyncServerDatasource) Events(ctx context.Context, eventIDs []string) ([]gomatrixserverlib.Event, error) {
streamEvents, err := d.events.selectEvents(ctx, nil, eventIDs)
if err != nil {
return nil, err
}
// We don't include a device here as we only include transaction IDs in
// incremental syncs.
return streamEventsToEvents(nil, streamEvents), nil
}
// WriteEvent into the database. It is not safe to call this function from multiple goroutines, as it would create races
// when generating the sync stream position for this event. Returns the sync stream position for the inserted event.
// Returns an error if there was a problem inserting this event.
func (d *SyncServerDatasource) WriteEvent(
ctx context.Context,
ev *gomatrixserverlib.Event,
addStateEvents []gomatrixserverlib.Event,
addStateEventIDs, removeStateEventIDs []string,
transactionID *api.TransactionID,
) (pduPosition int64, returnErr error) {
returnErr = common.WithTransaction(d.db, func(txn *sql.Tx) error {
var err error
pos, err := d.events.insertEvent(ctx, txn, ev, addStateEventIDs, removeStateEventIDs, transactionID)
if err != nil {
return err
}
pduPosition = pos
if len(addStateEvents) == 0 && len(removeStateEventIDs) == 0 {
// Nothing to do, the event may have just been a message event.
return nil
}
return d.updateRoomState(ctx, txn, removeStateEventIDs, addStateEvents, pduPosition)
})
return
}
func (d *SyncServerDatasource) updateRoomState(
ctx context.Context, txn *sql.Tx,
removedEventIDs []string,
addedEvents []gomatrixserverlib.Event,
pduPosition int64,
) error {
// remove first, then add, as we do not ever delete state, but do replace state which is a remove followed by an add.
for _, eventID := range removedEventIDs {
if err := d.roomstate.deleteRoomStateByEventID(ctx, txn, eventID); err != nil {
return err
}
}
for _, event := range addedEvents {
if event.StateKey() == nil {
// ignore non state events
continue
}
var membership *string
if event.Type() == "m.room.member" {
value, err := event.Membership()
if err != nil {
return err
}
membership = &value
}
if err := d.roomstate.upsertRoomState(ctx, txn, event, membership, pduPosition); err != nil {
return err
}
}
return nil
}
// GetStateEvent returns the Matrix state event of a given type for a given room with a given state key
// If no event could be found, returns nil
// If there was an issue during the retrieval, returns an error
func (d *SyncServerDatasource) GetStateEvent(
ctx context.Context, roomID, evType, stateKey string,
) (*gomatrixserverlib.Event, error) {
return d.roomstate.selectStateEvent(ctx, roomID, evType, stateKey)
}
// GetStateEventsForRoom fetches the state events for a given room.
// Returns an empty slice if no state events could be found for this room.
// Returns an error if there was an issue with the retrieval.
func (d *SyncServerDatasource) GetStateEventsForRoom(
ctx context.Context, roomID string,
) (stateEvents []gomatrixserverlib.Event, err error) {
err = common.WithTransaction(d.db, func(txn *sql.Tx) error {
stateEvents, err = d.roomstate.selectCurrentState(ctx, txn, roomID)
return err
})
return
}
// SyncPosition returns the latest positions for syncing.
func (d *SyncServerDatasource) SyncPosition(ctx context.Context) (types.SyncPosition, error) {
return d.syncPositionTx(ctx, nil)
}
func (d *SyncServerDatasource) syncPositionTx(
ctx context.Context, txn *sql.Tx,
) (sp types.SyncPosition, err error) {
maxEventID, err := d.events.selectMaxEventID(ctx, txn)
if err != nil {
return sp, err
}
maxAccountDataID, err := d.accountData.selectMaxAccountDataID(ctx, txn)
if err != nil {
return sp, err
}
if maxAccountDataID > maxEventID {
maxEventID = maxAccountDataID
}
maxInviteID, err := d.invites.selectMaxInviteID(ctx, txn)
if err != nil {
return sp, err
}
if maxInviteID > maxEventID {
maxEventID = maxInviteID
}
sp.PDUPosition = maxEventID
sp.TypingPosition = d.typingCache.GetLatestSyncPosition()
return
}
// addPDUDeltaToResponse adds all PDU deltas to a sync response.
// IDs of all rooms the user joined are returned so EDU deltas can be added for them.
func (d *SyncServerDatasource) addPDUDeltaToResponse(
ctx context.Context,
device authtypes.Device,
fromPos, toPos int64,
numRecentEventsPerRoom int,
res *types.Response,
) ([]string, error) {
txn, err := d.db.BeginTx(ctx, &txReadOnlySnapshot)
if err != nil {
return nil, err
}
var succeeded bool
defer common.EndTransaction(txn, &succeeded)
// Work out which rooms to return in the response. This is done by getting not only the currently
// joined rooms, but also which rooms have membership transitions for this user between the 2 PDU stream positions.
// This works out what the 'state' key should be for each room as well as which membership block
// to put the room into.
deltas, joinedRoomIDs, err := d.getStateDeltas(ctx, &device, txn, fromPos, toPos, device.UserID)
if err != nil {
return nil, err
}
for _, delta := range deltas {
err = d.addRoomDeltaToResponse(ctx, &device, txn, fromPos, toPos, delta, numRecentEventsPerRoom, res)
if err != nil {
return nil, err
}
}
// TODO: This should be done in getStateDeltas
if err = d.addInvitesToResponse(ctx, txn, device.UserID, fromPos, toPos, res); err != nil {
return nil, err
}
succeeded = true
return joinedRoomIDs, nil
}
// addTypingDeltaToResponse adds all typing notifications to a sync response
// since the specified position.
func (d *SyncServerDatasource) addTypingDeltaToResponse(
since int64,
joinedRoomIDs []string,
res *types.Response,
) error {
var jr types.JoinResponse
var ok bool
var err error
for _, roomID := range joinedRoomIDs {
if typingUsers, updated := d.typingCache.GetTypingUsersIfUpdatedAfter(
roomID, since,
); updated {
ev := gomatrixserverlib.ClientEvent{
Type: gomatrixserverlib.MTyping,
}
ev.Content, err = json.Marshal(map[string]interface{}{
"user_ids": typingUsers,
})
if err != nil {
return err
}
if jr, ok = res.Rooms.Join[roomID]; !ok {
jr = *types.NewJoinResponse()
}
jr.Ephemeral.Events = append(jr.Ephemeral.Events, ev)
res.Rooms.Join[roomID] = jr
}
}
return nil
}
// addEDUDeltaToResponse adds updates for EDUs of each type since fromPos if
// the positions of that type are not equal in fromPos and toPos.
func (d *SyncServerDatasource) addEDUDeltaToResponse(
fromPos, toPos types.SyncPosition,
joinedRoomIDs []string,
res *types.Response,
) (err error) {
if fromPos.TypingPosition != toPos.TypingPosition {
err = d.addTypingDeltaToResponse(
fromPos.TypingPosition, joinedRoomIDs, res,
)
}
return
}
// IncrementalSync returns all the data needed in order to create an incremental
// sync response for the given user. Events returned will include any client
// transaction IDs associated with the given device. These transaction IDs come
// from when the device sent the event via an API that included a transaction
// ID.
func (d *SyncServerDatasource) IncrementalSync(
ctx context.Context,
device authtypes.Device,
fromPos, toPos types.SyncPosition,
numRecentEventsPerRoom int,
) (*types.Response, error) {
nextBatchPos := fromPos.WithUpdates(toPos)
res := types.NewResponse(nextBatchPos)
var joinedRoomIDs []string
var err error
if fromPos.PDUPosition != toPos.PDUPosition {
joinedRoomIDs, err = d.addPDUDeltaToResponse(
ctx, device, fromPos.PDUPosition, toPos.PDUPosition, numRecentEventsPerRoom, res,
)
} else {
joinedRoomIDs, err = d.roomstate.selectRoomIDsWithMembership(
ctx, nil, device.UserID, membershipJoin,
)
}
if err != nil {
return nil, err
}
err = d.addEDUDeltaToResponse(
fromPos, toPos, joinedRoomIDs, res,
)
if err != nil {
return nil, err
}
return res, nil
}
// getResponseWithPDUsForCompleteSync creates a response and adds all PDUs needed
// to it. It returns toPos and joinedRoomIDs for use of adding EDUs.
func (d *SyncServerDatasource) getResponseWithPDUsForCompleteSync(
ctx context.Context,
userID string,
numRecentEventsPerRoom int,
) (
res *types.Response,
toPos types.SyncPosition,
joinedRoomIDs []string,
err error,
) {
// This needs to be all done in a transaction as we need to do multiple SELECTs, and we need to have
// a consistent view of the database throughout. This includes extracting the sync position.
// This does have the unfortunate side-effect that all the matrixy logic resides in this function,
// but it's better to not hide the fact that this is being done in a transaction.
txn, err := d.db.BeginTx(ctx, &txReadOnlySnapshot)
if err != nil {
return
}
var succeeded bool
defer common.EndTransaction(txn, &succeeded)
// Get the current sync position which we will base the sync response on.
toPos, err = d.syncPositionTx(ctx, txn)
if err != nil {
return
}
res = types.NewResponse(toPos)
// Extract room state and recent events for all rooms the user is joined to.
joinedRoomIDs, err = d.roomstate.selectRoomIDsWithMembership(ctx, txn, userID, membershipJoin)
if err != nil {
return
}
// Build up a /sync response. Add joined rooms.
for _, roomID := range joinedRoomIDs {
var stateEvents []gomatrixserverlib.Event
stateEvents, err = d.roomstate.selectCurrentState(ctx, txn, roomID)
if err != nil {
return
}
// TODO: When filters are added, we may need to call this multiple times to get enough events.
// See: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L316
var recentStreamEvents []streamEvent
recentStreamEvents, err = d.events.selectRecentEvents(
ctx, txn, roomID, 0, toPos.PDUPosition, numRecentEventsPerRoom,
)
if err != nil {
return
}
// We don't include a device here as we don't need to send down
// transaction IDs for complete syncs
recentEvents := streamEventsToEvents(nil, recentStreamEvents)
stateEvents = removeDuplicates(stateEvents, recentEvents)
jr := types.NewJoinResponse()
if prevPDUPos := recentStreamEvents[0].streamPosition - 1; prevPDUPos > 0 {
// Use the short form of batch token for prev_batch
jr.Timeline.PrevBatch = strconv.FormatInt(prevPDUPos, 10)
} else {
// Use the short form of batch token for prev_batch
jr.Timeline.PrevBatch = "1"
}
jr.Timeline.Events = gomatrixserverlib.ToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
jr.Timeline.Limited = true
jr.State.Events = gomatrixserverlib.ToClientEvents(stateEvents, gomatrixserverlib.FormatSync)
res.Rooms.Join[roomID] = *jr
}
if err = d.addInvitesToResponse(ctx, txn, userID, 0, toPos.PDUPosition, res); err != nil {
return
}
succeeded = true
return res, toPos, joinedRoomIDs, err
}
// CompleteSync returns a complete /sync API response for the given user.
func (d *SyncServerDatasource) CompleteSync(
ctx context.Context, userID string, numRecentEventsPerRoom int,
) (*types.Response, error) {
res, toPos, joinedRoomIDs, err := d.getResponseWithPDUsForCompleteSync(
ctx, userID, numRecentEventsPerRoom,
)
if err != nil {
return nil, err
}
// Use a zero value SyncPosition for fromPos so all EDU states are added.
err = d.addEDUDeltaToResponse(
types.SyncPosition{}, toPos, joinedRoomIDs, res,
)
if err != nil {
return nil, err
}
return res, nil
}
var txReadOnlySnapshot = sql.TxOptions{
// Set the isolation level so that we see a snapshot of the database.
// In PostgreSQL repeatable read transactions will see a snapshot taken
// at the first query, and since the transaction is read-only it can't
// run into any serialisation errors.
// https://www.postgresql.org/docs/9.5/static/transaction-iso.html#XACT-REPEATABLE-READ
Isolation: sql.LevelRepeatableRead,
ReadOnly: true,
}
// GetAccountDataInRange returns all account data for a given user inserted or
// updated between two given positions
// Returns a map following the format data[roomID] = []dataTypes
// If no data is retrieved, returns an empty map
// If there was an issue with the retrieval, returns an error
func (d *SyncServerDatasource) GetAccountDataInRange(
ctx context.Context, userID string, oldPos, newPos int64,
) (map[string][]string, error) {
return d.accountData.selectAccountDataInRange(ctx, userID, oldPos, newPos)
}
// UpsertAccountData keeps track of new or updated account data, by saving the type
// of the new/updated data, and the user ID and room ID the data is related to (empty)
// room ID means the data isn't specific to any room)
// If no data with the given type, user ID and room ID exists in the database,
// creates a new row, else update the existing one
// Returns an error if there was an issue with the upsert
func (d *SyncServerDatasource) UpsertAccountData(
ctx context.Context, userID, roomID, dataType string,
) (int64, error) {
return d.accountData.insertAccountData(ctx, userID, roomID, dataType)
}
// AddInviteEvent stores a new invite event for a user.
// If the invite was successfully stored this returns the stream ID it was stored at.
// Returns an error if there was a problem communicating with the database.
func (d *SyncServerDatasource) AddInviteEvent(
ctx context.Context, inviteEvent gomatrixserverlib.Event,
) (int64, error) {
return d.invites.insertInviteEvent(ctx, inviteEvent)
}
// RetireInviteEvent removes an old invite event from the database.
// Returns an error if there was a problem communicating with the database.
func (d *SyncServerDatasource) RetireInviteEvent(
ctx context.Context, inviteEventID string,
) error {
// TODO: Record that invite has been retired in a stream so that we can
// notify the user in an incremental sync.
err := d.invites.deleteInviteEvent(ctx, inviteEventID)
return err
}
func (d *SyncServerDatasource) SetTypingTimeoutCallback(fn cache.TimeoutCallbackFn) {
d.typingCache.SetTimeoutCallback(fn)
}
// AddTypingUser adds a typing user to the typing cache.
// Returns the newly calculated sync position for typing notifications.
func (d *SyncServerDatasource) AddTypingUser(
userID, roomID string, expireTime *time.Time,
) int64 {
return d.typingCache.AddTypingUser(userID, roomID, expireTime)
}
// RemoveTypingUser removes a typing user from the typing cache.
// Returns the newly calculated sync position for typing notifications.
func (d *SyncServerDatasource) RemoveTypingUser(
userID, roomID string,
) int64 {
return d.typingCache.RemoveUser(userID, roomID)
}
func (d *SyncServerDatasource) addInvitesToResponse(
ctx context.Context, txn *sql.Tx,
userID string,
fromPos, toPos int64,
res *types.Response,
) error {
invites, err := d.invites.selectInviteEventsInRange(
ctx, txn, userID, int64(fromPos), int64(toPos),
)
if err != nil {
return err
}
for roomID, inviteEvent := range invites {
ir := types.NewInviteResponse()
ir.InviteState.Events = gomatrixserverlib.ToClientEvents(
[]gomatrixserverlib.Event{inviteEvent}, gomatrixserverlib.FormatSync,
)
// TODO: add the invite state from the invite event.
res.Rooms.Invite[roomID] = *ir
}
return nil
}
// addRoomDeltaToResponse adds a room state delta to a sync response
func (d *SyncServerDatasource) addRoomDeltaToResponse(
ctx context.Context,
device *authtypes.Device,
txn *sql.Tx,
fromPos, toPos int64,
delta stateDelta,
numRecentEventsPerRoom int,
res *types.Response,
) error {
endPos := toPos
if delta.membershipPos > 0 && delta.membership == membershipLeave {
// make sure we don't leak recent events after the leave event.
// TODO: History visibility makes this somewhat complex to handle correctly. For example:
// TODO: This doesn't work for join -> leave in a single /sync request (see events prior to join).
// TODO: This will fail on join -> leave -> sensitive msg -> join -> leave
// in a single /sync request
// This is all "okay" assuming history_visibility == "shared" which it is by default.
endPos = delta.membershipPos
}
recentStreamEvents, err := d.events.selectRecentEvents(
ctx, txn, delta.roomID, fromPos, endPos, numRecentEventsPerRoom,
)
if err != nil {
return err
}
recentEvents := streamEventsToEvents(device, recentStreamEvents)
delta.stateEvents = removeDuplicates(delta.stateEvents, recentEvents) // roll back
// Don't bother appending empty room entries
if len(recentEvents) == 0 && len(delta.stateEvents) == 0 {
return nil
}
switch delta.membership {
case membershipJoin:
jr := types.NewJoinResponse()
if prevPDUPos := recentStreamEvents[0].streamPosition - 1; prevPDUPos > 0 {
// Use the short form of batch token for prev_batch
jr.Timeline.PrevBatch = strconv.FormatInt(prevPDUPos, 10)
} else {
// Use the short form of batch token for prev_batch
jr.Timeline.PrevBatch = "1"
}
jr.Timeline.Events = gomatrixserverlib.ToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
jr.Timeline.Limited = false // TODO: if len(events) >= numRecents + 1 and then set limited:true
jr.State.Events = gomatrixserverlib.ToClientEvents(delta.stateEvents, gomatrixserverlib.FormatSync)
res.Rooms.Join[delta.roomID] = *jr
case membershipLeave:
fallthrough // transitions to leave are the same as ban
case membershipBan:
// TODO: recentEvents may contain events that this user is not allowed to see because they are
// no longer in the room.
lr := types.NewLeaveResponse()
if prevPDUPos := recentStreamEvents[0].streamPosition - 1; prevPDUPos > 0 {
// Use the short form of batch token for prev_batch
lr.Timeline.PrevBatch = strconv.FormatInt(prevPDUPos, 10)
} else {
// Use the short form of batch token for prev_batch
lr.Timeline.PrevBatch = "1"
}
lr.Timeline.Events = gomatrixserverlib.ToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
lr.Timeline.Limited = false // TODO: if len(events) >= numRecents + 1 and then set limited:true
lr.State.Events = gomatrixserverlib.ToClientEvents(delta.stateEvents, gomatrixserverlib.FormatSync)
res.Rooms.Leave[delta.roomID] = *lr
}
return nil
}
// fetchStateEvents converts the set of event IDs into a set of events. It will fetch any which are missing from the database.
// Returns a map of room ID to list of events.
func (d *SyncServerDatasource) fetchStateEvents(
ctx context.Context, txn *sql.Tx,
roomIDToEventIDSet map[string]map[string]bool,
eventIDToEvent map[string]streamEvent,
) (map[string][]streamEvent, error) {
stateBetween := make(map[string][]streamEvent)
missingEvents := make(map[string][]string)
for roomID, ids := range roomIDToEventIDSet {
events := stateBetween[roomID]
for id, need := range ids {
if !need {
continue // deleted state
}
e, ok := eventIDToEvent[id]
if ok {
events = append(events, e)
} else {
m := missingEvents[roomID]
m = append(m, id)
missingEvents[roomID] = m
}
}
stateBetween[roomID] = events
}
if len(missingEvents) > 0 {
// This happens when add_state_ids has an event ID which is not in the provided range.
// We need to explicitly fetch them.
allMissingEventIDs := []string{}
for _, missingEvIDs := range missingEvents {
allMissingEventIDs = append(allMissingEventIDs, missingEvIDs...)
}
evs, err := d.fetchMissingStateEvents(ctx, txn, allMissingEventIDs)
if err != nil {
return nil, err
}
// we know we got them all otherwise an error would've been returned, so just loop the events
for _, ev := range evs {
roomID := ev.RoomID()
stateBetween[roomID] = append(stateBetween[roomID], ev)
}
}
return stateBetween, nil
}
func (d *SyncServerDatasource) fetchMissingStateEvents(
ctx context.Context, txn *sql.Tx, eventIDs []string,
) ([]streamEvent, error) {
// Fetch from the events table first so we pick up the stream ID for the
// event.
events, err := d.events.selectEvents(ctx, txn, eventIDs)
if err != nil {
return nil, err
}
have := map[string]bool{}
for _, event := range events {
have[event.EventID()] = true
}
var missing []string
for _, eventID := range eventIDs {
if !have[eventID] {
missing = append(missing, eventID)
}
}
if len(missing) == 0 {
return events, nil
}
// If they are missing from the events table then they should be state
// events that we received from outside the main event stream.
// These should be in the room state table.
stateEvents, err := d.roomstate.selectEventsWithEventIDs(ctx, txn, missing)
if err != nil {
return nil, err
}
if len(stateEvents) != len(missing) {
return nil, fmt.Errorf("failed to map all event IDs to events: (got %d, wanted %d)", len(stateEvents), len(missing))
}
events = append(events, stateEvents...)
return events, nil
}
// getStateDeltas returns the state deltas between fromPos and toPos,
// exclusive of oldPos, inclusive of newPos, for the rooms in which
// the user has new membership events.
// A list of joined room IDs is also returned in case the caller needs it.
func (d *SyncServerDatasource) getStateDeltas(
ctx context.Context, device *authtypes.Device, txn *sql.Tx,
fromPos, toPos int64, userID string,
) ([]stateDelta, []string, error) {
// Implement membership change algorithm: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L821
// - Get membership list changes for this user in this sync response
// - For each room which has membership list changes:
// * Check if the room is 'newly joined' (insufficient to just check for a join event because we allow dupe joins TODO).
// If it is, then we need to send the full room state down (and 'limited' is always true).
// * Check if user is still CURRENTLY invited to the room. If so, add room to 'invited' block.
// * Check if the user is CURRENTLY (TODO) left/banned. If so, add room to 'archived' block.
// - Get all CURRENTLY joined rooms, and add them to 'joined' block.
var deltas []stateDelta
// get all the state events ever between these two positions
stateNeeded, eventMap, err := d.events.selectStateInRange(ctx, txn, fromPos, toPos)
if err != nil {
return nil, nil, err
}
state, err := d.fetchStateEvents(ctx, txn, stateNeeded, eventMap)
if err != nil {
return nil, nil, err
}
for roomID, stateStreamEvents := range state {
for _, ev := range stateStreamEvents {
// TODO: Currently this will incorrectly add rooms which were ALREADY joined but they sent another no-op join event.
// We should be checking if the user was already joined at fromPos and not proceed if so. As a result of this,
// dupe join events will result in the entire room state coming down to the client again. This is added in
// the 'state' part of the response though, so is transparent modulo bandwidth concerns as it is not added to
// the timeline.
if membership := getMembershipFromEvent(&ev.Event, userID); membership != "" {
if membership == membershipJoin {
// send full room state down instead of a delta
var allState []gomatrixserverlib.Event
allState, err = d.roomstate.selectCurrentState(ctx, txn, roomID)
if err != nil {
return nil, nil, err
}
s := make([]streamEvent, len(allState))
for i := 0; i < len(s); i++ {
s[i] = streamEvent{Event: allState[i], streamPosition: 0}
}
state[roomID] = s
continue // we'll add this room in when we do joined rooms
}
deltas = append(deltas, stateDelta{
membership: membership,
membershipPos: ev.streamPosition,
stateEvents: streamEventsToEvents(device, stateStreamEvents),
roomID: roomID,
})
break
}
}
}
// Add in currently joined rooms
joinedRoomIDs, err := d.roomstate.selectRoomIDsWithMembership(ctx, txn, userID, membershipJoin)
if err != nil {
return nil, nil, err
}
for _, joinedRoomID := range joinedRoomIDs {
deltas = append(deltas, stateDelta{
membership: membershipJoin,
stateEvents: streamEventsToEvents(device, state[joinedRoomID]),
roomID: joinedRoomID,
})
}
return deltas, joinedRoomIDs, nil
}
// streamEventsToEvents converts streamEvent to Event. If device is non-nil and
// matches the streamevent.transactionID device then the transaction ID gets
// added to the unsigned section of the output event.
func streamEventsToEvents(device *authtypes.Device, in []streamEvent) []gomatrixserverlib.Event {
out := make([]gomatrixserverlib.Event, len(in))
for i := 0; i < len(in); i++ {
out[i] = in[i].Event
if device != nil && in[i].transactionID != nil {
if device.UserID == in[i].Sender() && device.ID == in[i].transactionID.DeviceID {
err := out[i].SetUnsignedField(
"transaction_id", in[i].transactionID.TransactionID,
)
if err != nil {
logrus.WithFields(logrus.Fields{
"event_id": out[i].EventID(),
}).WithError(err).Warnf("Failed to add transaction ID to event")
}
}
}
}
return out
}
// There may be some overlap where events in stateEvents are already in recentEvents, so filter
// them out so we don't include them twice in the /sync response. They should be in recentEvents
// only, so clients get to the correct state once they have rolled forward.
func removeDuplicates(stateEvents, recentEvents []gomatrixserverlib.Event) []gomatrixserverlib.Event {
for _, recentEv := range recentEvents {
if recentEv.StateKey() == nil {
continue // not a state event
}
// TODO: This is a linear scan over all the current state events in this room. This will
// be slow for big rooms. We should instead sort the state events by event ID (ORDER BY)
// then do a binary search to find matching events, similar to what roomserver does.
for j := 0; j < len(stateEvents); j++ {
if stateEvents[j].EventID() == recentEv.EventID() {
// overwrite the element to remove with the last element then pop the last element.
// This is orders of magnitude faster than re-slicing, but doesn't preserve ordering
// (we don't care about the order of stateEvents)
stateEvents[j] = stateEvents[len(stateEvents)-1]
stateEvents = stateEvents[:len(stateEvents)-1]
break // there shouldn't be multiple events with the same event ID
}
}
}
return stateEvents
}
// getMembershipFromEvent returns the value of content.membership iff the event is a state event
// with type 'm.room.member' and state_key of userID. Otherwise, an empty string is returned.
func getMembershipFromEvent(ev *gomatrixserverlib.Event, userID string) string {
if ev.Type() == "m.room.member" && ev.StateKeyEquals(userID) {
membership, err := ev.Membership()
if err != nil {
return ""
}
return membership
}
return ""
}