Add missing file

Author: kegsay

eventV3.go

@@ -0,0 +1,161 @@
+package gomatrixserverlib
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/gomatrixserverlib/spec"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+type eventV3 struct {
+	eventV2
+}
+
+func (e *eventV3) RoomID() spec.RoomID {
+	roomIDStr := e.eventFields.RoomID
+	isCreateEvent := e.Type() == spec.MRoomCreate && e.StateKeyEquals("")
+	if isCreateEvent {
+		roomIDStr = fmt.Sprintf("!%s", e.EventID()[1:])
+	}
+	roomID, err := spec.NewRoomID(roomIDStr)
+	if err != nil {
+		panic(fmt.Errorf("RoomID is invalid: %w", err))
+	}
+	return *roomID
+}
+
+func (e *eventV3) AuthEventIDs() []string {
+	isCreateEvent := e.Type() == spec.MRoomCreate && e.StateKeyEquals("")
+	if isCreateEvent {
+		return []string{}
+	}
+	createEventID := fmt.Sprintf("$%s", e.eventFields.RoomID[1:])
+	if len(e.AuthEvents) > 0 {
+		// always include the create event
+		return append([]string{createEventID}, e.AuthEvents...)
+	}
+	return []string{createEventID}
+}
+
+func newEventFromUntrustedJSONV3(eventJSON []byte, roomVersion IRoomVersion) (PDU, error) {
+	if r := gjson.GetBytes(eventJSON, "_*"); r.Exists() {
+		return nil, fmt.Errorf("gomatrixserverlib NewEventFromUntrustedJSON: found top-level '_' key, is this a headered event: %v", string(eventJSON))
+	}
+	if err := roomVersion.CheckCanonicalJSON(eventJSON); err != nil {
+		return nil, BadJSONError{err}
+	}
+
+	res := &eventV3{}
+	var err error
+	// Synapse removes these keys from events in case a server accidentally added them.
+	// https://github.com/matrix-org/synapse/blob/v0.18.5/synapse/crypto/event_signing.py#L57-L62
+	for _, key := range []string{"outlier", "destinations", "age_ts", "unsigned", "event_id"} {
+		if eventJSON, err = sjson.DeleteBytes(eventJSON, key); err != nil {
+			return nil, err
+		}
+	}
+
+	if err = json.Unmarshal(eventJSON, &res); err != nil {
+		return nil, err
+	}
+
+	// v3 events have room IDs as the create event ID.
+	// TODO: allow validation to be enhanced/relaxed to help users like Complement.
+	if err := checkRoomID(res); err != nil {
+		return nil, err
+	}
+
+	res.roomVersion = roomVersion.Version()
+
+	// We know the JSON must be valid here.
+	eventJSON = CanonicalJSONAssumeValid(eventJSON)
+	res.eventJSON = eventJSON
+
+	if err = checkEventContentHash(eventJSON); err != nil {
+		res.redacted = true
+
+		// If the content hash doesn't match then we have to discard all non-essential fields
+		// because they've been tampered with.
+		var redactedJSON []byte
+		if redactedJSON, err = roomVersion.RedactEventJSON(eventJSON); err != nil {
+			return nil, err
+		}
+
+		redactedJSON = CanonicalJSONAssumeValid(redactedJSON)
+
+		// We need to ensure that `result` is the redacted event.
+		// If redactedJSON is the same as eventJSON then `result` is already
+		// correct. If not then we need to reparse.
+		//
+		// Yes, this means that for some events we parse twice (which is slow),
+		// but means that parsing unredacted events is fast.
+		if !bytes.Equal(redactedJSON, eventJSON) {
+			result, err := roomVersion.NewEventFromTrustedJSON(redactedJSON, true)
+			if err != nil {
+				return nil, err
+			}
+			err = CheckFields(result)
+			return result, err
+		}
+	}
+
+	err = CheckFields(res)
+
+	return res, err
+}
+
+func newEventFromTrustedJSONV3(eventJSON []byte, redacted bool, roomVersion IRoomVersion) (PDU, error) {
+	res := eventV3{}
+	if err := json.Unmarshal(eventJSON, &res); err != nil {
+		return nil, err
+	}
+
+	// v3 events have room IDs as the create event ID.
+	// TODO: allow validation to be enhanced/relaxed to help users like Complement.
+	// TODO: feels weird to only have this validation here and not length checks etc :S
+	if err := checkRoomID(&res); err != nil {
+		return nil, err
+	}
+
+	res.roomVersion = roomVersion.Version()
+	res.redacted = redacted
+	res.eventJSON = eventJSON
+	return &res, nil
+}
+
+func newEventFromTrustedJSONWithEventIDV3(eventID string, eventJSON []byte, redacted bool, roomVersion IRoomVersion) (PDU, error) {
+	res := &eventV3{}
+	if err := json.Unmarshal(eventJSON, &res); err != nil {
+		return nil, err
+	}
+
+	// v3 events have room IDs as the create event ID.
+	// TODO: allow validation to be enhanced/relaxed to help users like Complement.
+	if err := checkRoomID(res); err != nil {
+		return nil, err
+	}
+
+	res.roomVersion = roomVersion.Version()
+	res.eventJSON = eventJSON
+	res.EventIDRaw = eventID
+	res.redacted = redacted
+	return res, nil
+}
+
+func checkRoomID(res *eventV3) error {
+	isCreateEvent := res.Type() == spec.MRoomCreate && res.StateKeyEquals("")
+	// TODO: We can't do this so long as we support partial Hydra impls in Complement
+	// because otherwise if MSC4291=0 and MSC4289=1 then this check fails as the create
+	// event will have a room_id.
+	if isCreateEvent && res.eventFields.RoomID != "" {
+		//return fmt.Errorf("gomatrixserverlib: room_id must not exist on create event")
+	}
+	if !isCreateEvent && !strings.HasPrefix(res.eventFields.RoomID, "!") {
+		return fmt.Errorf("gomatrixserverlib: room_id must start with !")
+	}
+	return nil
+}