dendrite/src/github.com/matrix-org/dendrite/roomserver/input/events.go

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package input
import (
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
)
// A RoomEventDatabase has the storage APIs needed to store a room event.
type RoomEventDatabase interface {
state.RoomStateDatabase
// Stores a matrix room event in the database
StoreEvent(event gomatrixserverlib.Event, authEventNIDs []types.EventNID) (types.RoomNID, types.StateAtEvent, error)
// Lookup the state entries for a list of string event IDs
// Returns an error if the there is an error talking to the database
// or if the event IDs aren't in the database.
StateEntriesForEventIDs(eventIDs []string) ([]types.StateEntry, error)
// Lookup the Events for a list of numeric event IDs.
// Returns a sorted list of events.
Events(eventNIDs []types.EventNID) ([]types.Event, error)
// Lookup the state of a room at each event for a list of string event IDs.
// Returns an error if there is an error talking to the database
// or if the room state for the event IDs aren't in the database
StateAtEventIDs(eventIDs []string) ([]types.StateAtEvent, error)
// Store the room state at an event in the database
AddState(roomNID types.RoomNID, stateBlockNIDs []types.StateBlockNID, state []types.StateEntry) (types.StateSnapshotNID, error)
// Set the state at an event.
SetState(eventNID types.EventNID, stateNID types.StateSnapshotNID) error
// Lookup the latest events in a room in preparation for an update.
// The RoomRecentEventsUpdater must have Commit or Rollback called on it if this doesn't return an error.
// Returns the latest events in the room and the last eventID sent to the log along with an updater.
// If this returns an error then no further action is required.
GetLatestEventsForUpdate(roomNID types.RoomNID) (updater types.RoomRecentEventsUpdater, err error)
// Lookup the string event IDs for a list of numeric event IDs
EventIDs(eventNIDs []types.EventNID) (map[types.EventNID]string, error)
}
// OutputRoomEventWriter has the APIs needed to write an event to the output logs.
type OutputRoomEventWriter interface {
// Write an event.
WriteOutputRoomEvent(output api.OutputRoomEvent) error
}
func processRoomEvent(db RoomEventDatabase, ow OutputRoomEventWriter, input api.InputRoomEvent) error {
// Parse and validate the event JSON
event, err := gomatrixserverlib.NewEventFromUntrustedJSON(input.Event)
if err != nil {
return err
}
// Check that the event passes authentication checks and work out the numeric IDs for the auth events.
authEventNIDs, err := checkAuthEvents(db, event, input.AuthEventIDs)
if err != nil {
return err
}
// Store the event
roomNID, stateAtEvent, err := db.StoreEvent(event, authEventNIDs)
if err != nil {
return err
}
if input.Kind == api.KindOutlier {
// For outliers we can stop after we've stored the event itself as it
// doesn't have any associated state to store and we don't need to
// notify anyone about it.
return nil
}
if stateAtEvent.BeforeStateSnapshotNID == 0 {
// We haven't calculated a state for this event yet.
// Lets calculate one.
if input.HasState {
// We've been told what the state at the event is so we don't need to calculate it.
// Check that those state events are in the database and store the state.
entries, err := db.StateEntriesForEventIDs(input.StateEventIDs)
if err != nil {
return err
}
if stateAtEvent.BeforeStateSnapshotNID, err = db.AddState(roomNID, nil, entries); err != nil {
return nil
}
} else {
// We haven't been told what the state at the event is so we need to calculate it from the prev_events
if stateAtEvent.BeforeStateSnapshotNID, err = calculateAndStoreStateBeforeEvent(db, event, roomNID); err != nil {
return err
}
}
db.SetState(stateAtEvent.EventNID, stateAtEvent.BeforeStateSnapshotNID)
}
if input.Kind == api.KindBackfill {
// Backfill is not implemented.
panic("Not implemented")
}
// Update the extremities of the event graph for the room
if err := updateLatestEvents(db, ow, roomNID, stateAtEvent, event); err != nil {
return err
}
// TODO:
// * Caculate the new current state for the room if the forward extremities have changed.
// * Work out the delta between the new current state and the previous current state.
// * Work out the visibility of the event.
// * Write a message to the output logs containing:
// - The event itself
// - The visiblity of the event, i.e. who is allowed to see the event.
// - The changes to the current state of the room.
return nil
}