Add Queryer and Inputer and factor out more RSAPI stuff (#1382)

* Add Queryer and use embedded structs

* Add Inputer and factor out more RS API stuff

This neatly splits up the RS API based on the functionality it provides,
whilst providing a useful place for code sharing via the `helpers` package.

13 files changed, 249 insertions, 161 deletions

diff --git a/roomserver/internal/api.go b/roomserver/internal/api.go
index 8ac1bdda..93c0be77 100644
--- a/roomserver/internal/api.go
+++ b/roomserver/internal/api.go
@@ -2,20 +2,28 @@ package internal
 
 import (
 	"context"
-	"sync"
 
 	"github.com/Shopify/sarama"
 	fsAPI "github.com/matrix-org/dendrite/federationsender/api"
 	"github.com/matrix-org/dendrite/internal/caching"
 	"github.com/matrix-org/dendrite/internal/config"
 	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/roomserver/internal/input"
 	"github.com/matrix-org/dendrite/roomserver/internal/perform"
+	"github.com/matrix-org/dendrite/roomserver/internal/query"
 	"github.com/matrix-org/dendrite/roomserver/storage"
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
 // RoomserverInternalAPI is an implementation of api.RoomserverInternalAPI
 type RoomserverInternalAPI struct {
+	*input.Inputer
+	*query.Queryer
+	*perform.Inviter
+	*perform.Joiner
+	*perform.Leaver
+	*perform.Publisher
+	*perform.Backfiller
 	DB                   storage.Database
 	Cfg                  *config.RoomServer
 	Producer             sarama.SyncProducer
@@ -24,12 +32,6 @@ type RoomserverInternalAPI struct {
 	KeyRing              gomatrixserverlib.JSONVerifier
 	fsAPI                fsAPI.FederationSenderInternalAPI
 	OutputRoomEventTopic string // Kafka topic for new output room events
-	Inviter              *perform.Inviter
-	Joiner               *perform.Joiner
-	Leaver               *perform.Leaver
-	Publisher            *perform.Publisher
-	Backfiller           *perform.Backfiller
-	mutexes              sync.Map // room ID -> *sync.Mutex, protects calls to processRoomEvent
 }
 
 func NewRoomserverAPI(
@@ -38,13 +40,21 @@ func NewRoomserverAPI(
 	keyRing gomatrixserverlib.JSONVerifier,
 ) *RoomserverInternalAPI {
 	a := &RoomserverInternalAPI{
-		DB:                   roomserverDB,
-		Cfg:                  cfg,
-		Producer:             producer,
-		Cache:                caches,
-		ServerName:           cfg.Matrix.ServerName,
-		KeyRing:              keyRing,
-		OutputRoomEventTopic: outputRoomEventTopic,
+		DB:         roomserverDB,
+		Cfg:        cfg,
+		Cache:      caches,
+		ServerName: cfg.Matrix.ServerName,
+		KeyRing:    keyRing,
+		Queryer: &query.Queryer{
+			DB:    roomserverDB,
+			Cache: caches,
+		},
+		Inputer: &input.Inputer{
+			DB:                   roomserverDB,
+			OutputRoomEventTopic: outputRoomEventTopic,
+			Producer:             producer,
+			ServerName:           cfg.Matrix.ServerName,
+		},
 		// perform-er structs get initialised when we have a federation sender to use
 	}
 	return a
@@ -57,23 +67,23 @@ func (r *RoomserverInternalAPI) SetFederationSenderAPI(fsAPI fsAPI.FederationSen
 	r.fsAPI = fsAPI
 
 	r.Inviter = &perform.Inviter{
-		DB:    r.DB,
-		Cfg:   r.Cfg,
-		FSAPI: r.fsAPI,
-		RSAPI: r,
+		DB:      r.DB,
+		Cfg:     r.Cfg,
+		FSAPI:   r.fsAPI,
+		Inputer: r.Inputer,
 	}
 	r.Joiner = &perform.Joiner{
 		ServerName: r.Cfg.Matrix.ServerName,
 		Cfg:        r.Cfg,
 		DB:         r.DB,
 		FSAPI:      r.fsAPI,
-		RSAPI:      r,
+		Inputer:    r.Inputer,
 	}
 	r.Leaver = &perform.Leaver{
-		Cfg:   r.Cfg,
-		DB:    r.DB,
-		FSAPI: r.fsAPI,
-		RSAPI: r,
+		Cfg:     r.Cfg,
+		DB:      r.DB,
+		FSAPI:   r.fsAPI,
+		Inputer: r.Inputer,
 	}
 	r.Publisher = &perform.Publisher{
 		DB: r.DB,
@@ -101,14 +111,6 @@ func (r *RoomserverInternalAPI) PerformInvite(
 	return r.WriteOutputEvents(req.Event.RoomID(), outputEvents)
 }
 
-func (r *RoomserverInternalAPI) PerformJoin(
-	ctx context.Context,
-	req *api.PerformJoinRequest,
-	res *api.PerformJoinResponse,
-) {
-	r.Joiner.PerformJoin(ctx, req, res)
-}
-
 func (r *RoomserverInternalAPI) PerformLeave(
 	ctx context.Context,
 	req *api.PerformLeaveRequest,
@@ -123,20 +125,3 @@ func (r *RoomserverInternalAPI) PerformLeave(
 	}
 	return r.WriteOutputEvents(req.RoomID, outputEvents)
 }
-
-func (r *RoomserverInternalAPI) PerformPublish(
-	ctx context.Context,
-	req *api.PerformPublishRequest,
-	res *api.PerformPublishResponse,
-) {
-	r.Publisher.PerformPublish(ctx, req, res)
-}
-
-// Query a given amount (or less) of events prior to a given set of events.
-func (r *RoomserverInternalAPI) PerformBackfill(
-	ctx context.Context,
-	request *api.PerformBackfillRequest,
-	response *api.PerformBackfillResponse,
-) error {
-	return r.Backfiller.PerformBackfill(ctx, request, response)
-}
diff --git a/roomserver/internal/helpers/helpers.go b/roomserver/internal/helpers/helpers.go
index d7bb40af..b7e6ce86 100644
--- a/roomserver/internal/helpers/helpers.go
+++ b/roomserver/internal/helpers/helpers.go
@@ -324,3 +324,56 @@ BFSLoop:
 
 	return resultNIDs, err
 }
+
+func QueryLatestEventsAndState(
+	ctx context.Context, db storage.Database,
+	request *api.QueryLatestEventsAndStateRequest,
+	response *api.QueryLatestEventsAndStateResponse,
+) error {
+	roomInfo, err := db.RoomInfo(ctx, request.RoomID)
+	if err != nil {
+		return err
+	}
+	if roomInfo == nil || roomInfo.IsStub {
+		response.RoomExists = false
+		return nil
+	}
+
+	roomState := state.NewStateResolution(db, *roomInfo)
+	response.RoomExists = true
+	response.RoomVersion = roomInfo.RoomVersion
+
+	var currentStateSnapshotNID types.StateSnapshotNID
+	response.LatestEvents, currentStateSnapshotNID, response.Depth, err =
+		db.LatestEventIDs(ctx, roomInfo.RoomNID)
+	if err != nil {
+		return err
+	}
+
+	var stateEntries []types.StateEntry
+	if len(request.StateToFetch) == 0 {
+		// Look up all room state.
+		stateEntries, err = roomState.LoadStateAtSnapshot(
+			ctx, currentStateSnapshotNID,
+		)
+	} else {
+		// Look up the current state for the requested tuples.
+		stateEntries, err = roomState.LoadStateAtSnapshotForStringTuples(
+			ctx, currentStateSnapshotNID, request.StateToFetch,
+		)
+	}
+	if err != nil {
+		return err
+	}
+
+	stateEvents, err := LoadStateEvents(ctx, db, stateEntries)
+	if err != nil {
+		return err
+	}
+
+	for _, event := range stateEvents {
+		response.StateEvents = append(response.StateEvents, event.Headered(roomInfo.RoomVersion))
+	}
+
+	return nil
+}
diff --git a/roomserver/internal/input.go b/roomserver/internal/input/input.go
index dbf67b79..87bdc5db 100644
--- a/roomserver/internal/input.go
+++ b/roomserver/internal/input/input.go
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 // Package input contains the code processes new room events
-package internal
+package input
 
 import (
 	"context"
@@ -22,11 +22,22 @@ import (
 
 	"github.com/Shopify/sarama"
 	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/roomserver/storage"
+	"github.com/matrix-org/gomatrixserverlib"
 	log "github.com/sirupsen/logrus"
 )
 
+type Inputer struct {
+	DB                   storage.Database
+	Producer             sarama.SyncProducer
+	ServerName           gomatrixserverlib.ServerName
+	OutputRoomEventTopic string
+
+	mutexes sync.Map // room ID -> *sync.Mutex, protects calls to processRoomEvent
+}
+
 // WriteOutputEvents implements OutputRoomEventWriter
-func (r *RoomserverInternalAPI) WriteOutputEvents(roomID string, updates []api.OutputEvent) error {
+func (r *Inputer) WriteOutputEvents(roomID string, updates []api.OutputEvent) error {
 	messages := make([]*sarama.ProducerMessage, len(updates))
 	for i := range updates {
 		value, err := json.Marshal(updates[i])
@@ -58,7 +69,7 @@ func (r *RoomserverInternalAPI) WriteOutputEvents(roomID string, updates []api.O
 }
 
 // InputRoomEvents implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) InputRoomEvents(
+func (r *Inputer) InputRoomEvents(
 	ctx context.Context,
 	request *api.InputRoomEventsRequest,
 	response *api.InputRoomEventsResponse,
diff --git a/roomserver/internal/input_events.go b/roomserver/internal/input/input_events.go
index edc8b416..69f51f4b 100644
--- a/roomserver/internal/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -14,7 +14,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package input
 
 import (
 	"context"
@@ -36,7 +36,7 @@ import (
 // state deltas when sending to kafka streams
 // TODO: Break up function - we should probably do transaction ID checks before calling this.
 // nolint:gocyclo
-func (r *RoomserverInternalAPI) processRoomEvent(
+func (r *Inputer) processRoomEvent(
 	ctx context.Context,
 	input api.InputRoomEvent,
 ) (eventID string, err error) {
@@ -141,7 +141,7 @@ func (r *RoomserverInternalAPI) processRoomEvent(
 	return event.EventID(), nil
 }
 
-func (r *RoomserverInternalAPI) calculateAndSetState(
+func (r *Inputer) calculateAndSetState(
 	ctx context.Context,
 	input api.InputRoomEvent,
 	roomInfo types.RoomInfo,
diff --git a/roomserver/internal/input_latest_events.go b/roomserver/internal/input/input_latest_events.go
index d5e38e7a..67a7d8a4 100644
--- a/roomserver/internal/input_latest_events.go
+++ b/roomserver/internal/input/input_latest_events.go
@@ -14,7 +14,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package input
 
 import (
 	"bytes"
@@ -47,7 +47,7 @@ import (
 //      7 <----- latest
 //
 // Can only be called once at a time
-func (r *RoomserverInternalAPI) updateLatestEvents(
+func (r *Inputer) updateLatestEvents(
 	ctx context.Context,
 	roomInfo *types.RoomInfo,
 	stateAtEvent types.StateAtEvent,
@@ -87,7 +87,7 @@ func (r *RoomserverInternalAPI) updateLatestEvents(
 // when there are so many variables to pass around.
 type latestEventsUpdater struct {
 	ctx           context.Context
-	api           *RoomserverInternalAPI
+	api           *Inputer
 	updater       *shared.LatestEventsUpdater
 	roomInfo      *types.RoomInfo
 	stateAtEvent  types.StateAtEvent
diff --git a/roomserver/internal/input_membership.go b/roomserver/internal/input/input_membership.go
index 57a94596..8befcd64 100644
--- a/roomserver/internal/input_membership.go
+++ b/roomserver/internal/input/input_membership.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package input
 
 import (
 	"context"
@@ -29,7 +29,7 @@ import (
 // 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 (r *RoomserverInternalAPI) updateMemberships(
+func (r *Inputer) updateMemberships(
 	ctx context.Context,
 	updater *shared.LatestEventsUpdater,
 	removed, added []types.StateEntry,
@@ -78,7 +78,7 @@ func (r *RoomserverInternalAPI) updateMemberships(
 	return updates, nil
 }
 
-func (r *RoomserverInternalAPI) updateMembership(
+func (r *Inputer) updateMembership(
 	updater *shared.LatestEventsUpdater,
 	targetUserNID types.EventStateKeyNID,
 	remove, add *gomatrixserverlib.Event,
@@ -133,11 +133,11 @@ func (r *RoomserverInternalAPI) updateMembership(
 	}
 }
 
-func (r *RoomserverInternalAPI) isLocalTarget(event *gomatrixserverlib.Event) bool {
+func (r *Inputer) isLocalTarget(event *gomatrixserverlib.Event) bool {
 	isTargetLocalUser := false
 	if statekey := event.StateKey(); statekey != nil {
 		_, domain, _ := gomatrixserverlib.SplitID('@', *statekey)
-		isTargetLocalUser = domain == r.Cfg.Matrix.ServerName
+		isTargetLocalUser = domain == r.ServerName
 	}
 	return isTargetLocalUser
 }
diff --git a/roomserver/internal/perform/perform_backfill.go b/roomserver/internal/perform/perform_backfill.go
index d345e9c7..668c8078 100644
--- a/roomserver/internal/perform/perform_backfill.go
+++ b/roomserver/internal/perform/perform_backfill.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// 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 perform
 
 import (
diff --git a/roomserver/internal/perform/perform_invite.go b/roomserver/internal/perform/perform_invite.go
index 7320388e..e06ad062 100644
--- a/roomserver/internal/perform/perform_invite.go
+++ b/roomserver/internal/perform/perform_invite.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// 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 perform
 
 import (
@@ -8,6 +22,7 @@ import (
 	"github.com/matrix-org/dendrite/internal/config"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/internal/helpers"
+	"github.com/matrix-org/dendrite/roomserver/internal/input"
 	"github.com/matrix-org/dendrite/roomserver/state"
 	"github.com/matrix-org/dendrite/roomserver/storage"
 	"github.com/matrix-org/dendrite/roomserver/types"
@@ -16,12 +31,10 @@ import (
 )
 
 type Inviter struct {
-	DB    storage.Database
-	Cfg   *config.RoomServer
-	FSAPI federationSenderAPI.FederationSenderInternalAPI
-
-	// TODO FIXME: Remove this
-	RSAPI api.RoomserverInternalAPI
+	DB      storage.Database
+	Cfg     *config.RoomServer
+	FSAPI   federationSenderAPI.FederationSenderInternalAPI
+	Inputer *input.Inputer
 }
 
 // nolint:gocyclo
@@ -170,7 +183,7 @@ func (r *Inviter) PerformInvite(
 			},
 		}
 		inputRes := &api.InputRoomEventsResponse{}
-		if err = r.RSAPI.InputRoomEvents(context.Background(), inputReq, inputRes); err != nil {
+		if err = r.Inputer.InputRoomEvents(context.Background(), inputReq, inputRes); err != nil {
 			return nil, fmt.Errorf("r.InputRoomEvents: %w", err)
 		}
 	} else {
diff --git a/roomserver/internal/perform/perform_join.go b/roomserver/internal/perform/perform_join.go
index c8e6e8e6..3d194227 100644
--- a/roomserver/internal/perform/perform_join.go
+++ b/roomserver/internal/perform/perform_join.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// 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 perform
 
 import (
@@ -12,6 +26,7 @@ import (
 	"github.com/matrix-org/dendrite/internal/eventutil"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/internal/helpers"
+	"github.com/matrix-org/dendrite/roomserver/internal/input"
 	"github.com/matrix-org/dendrite/roomserver/storage"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/sirupsen/logrus"
@@ -23,8 +38,7 @@ type Joiner struct {
 	FSAPI      fsAPI.FederationSenderInternalAPI
 	DB         storage.Database
 
-	// TODO FIXME: Remove this
-	RSAPI api.RoomserverInternalAPI
+	Inputer *input.Inputer
 }
 
 // PerformJoin handles joining matrix rooms, including over federation by talking to the federationsender.
@@ -201,15 +215,7 @@ func (r *Joiner) performJoinRoomByID(
 	// locally on the homeserver.
 	// TODO: Check what happens if the room exists on the server
 	// but everyone has since left. I suspect it does the wrong thing.
-	buildRes := api.QueryLatestEventsAndStateResponse{}
-	event, err := eventutil.BuildEvent(
-		ctx,          // the request context
-		&eb,          // the template join event
-		r.Cfg.Matrix, // the server configuration
-		time.Now(),   // the event timestamp to use
-		r.RSAPI,      // the roomserver API to use
-		&buildRes,    // the query response
-	)
+	event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
 
 	switch err {
 	case nil:
@@ -241,7 +247,7 @@ func (r *Joiner) performJoinRoomByID(
 				},
 			}
 			inputRes := api.InputRoomEventsResponse{}
-			if err = r.RSAPI.InputRoomEvents(ctx, &inputReq, &inputRes); err != nil {
+			if err = r.Inputer.InputRoomEvents(ctx, &inputReq, &inputRes); err != nil {
 				var notAllowed *gomatrixserverlib.NotAllowed
 				if errors.As(err, &notAllowed) {
 					return "", &api.PerformError{
@@ -306,3 +312,31 @@ func (r *Joiner) performFederatedJoinRoomByID(
 	}
 	return nil
 }
+
+func buildEvent(
+	ctx context.Context, db storage.Database, cfg *config.Global, builder *gomatrixserverlib.EventBuilder,
+) (*gomatrixserverlib.HeaderedEvent, *api.QueryLatestEventsAndStateResponse, error) {
+	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
+	if err != nil {
+		return nil, nil, fmt.Errorf("gomatrixserverlib.StateNeededForEventBuilder: %w", err)
+	}
+
+	if len(eventsNeeded.Tuples()) == 0 {
+		return nil, nil, errors.New("expecting state tuples for event builder, got none")
+	}
+
+	var queryRes api.QueryLatestEventsAndStateResponse
+	err = helpers.QueryLatestEventsAndState(ctx, db, &api.QueryLatestEventsAndStateRequest{
+		RoomID:       builder.RoomID,
+		StateToFetch: eventsNeeded.Tuples(),
+	}, &queryRes)
+	if err != nil {
+		return nil, nil, fmt.Errorf("QueryLatestEventsAndState: %w", err)
+	}
+
+	ev, err := eventutil.BuildEvent(ctx, builder, cfg, time.Now(), &eventsNeeded, &queryRes)
+	if err != nil {
+		return nil, nil, err
+	}
+	return ev, &queryRes, nil
+}
diff --git a/roomserver/internal/perform/perform_leave.go b/roomserver/internal/perform/perform_leave.go
index b4053eed..aaa3b5b1 100644
--- a/roomserver/internal/perform/perform_leave.go
+++ b/roomserver/internal/perform/perform_leave.go
@@ -1,16 +1,29 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// 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 perform
 
 import (
 	"context"
 	"fmt"
 	"strings"
-	"time"
 
 	fsAPI "github.com/matrix-org/dendrite/federationsender/api"
 	"github.com/matrix-org/dendrite/internal/config"
-	"github.com/matrix-org/dendrite/internal/eventutil"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/internal/helpers"
+	"github.com/matrix-org/dendrite/roomserver/internal/input"
 	"github.com/matrix-org/dendrite/roomserver/storage"
 	"github.com/matrix-org/gomatrixserverlib"
 )
@@ -20,8 +33,7 @@ type Leaver struct {
 	DB    storage.Database
 	FSAPI fsAPI.FederationSenderInternalAPI
 
-	// TODO FIXME: Remove this
-	RSAPI api.RoomserverInternalAPI
+	Inputer *input.Inputer
 }
 
 // WriteOutputEvents implements OutputRoomEventWriter
@@ -67,7 +79,7 @@ func (r *Leaver) performLeaveRoomByID(
 		},
 	}
 	latestRes := api.QueryLatestEventsAndStateResponse{}
-	if err = r.RSAPI.QueryLatestEventsAndState(ctx, &latestReq, &latestRes); err != nil {
+	if err = helpers.QueryLatestEventsAndState(ctx, r.DB, &latestReq, &latestRes); err != nil {
 		return nil, err
 	}
 	if !latestRes.RoomExists {
@@ -108,15 +120,7 @@ func (r *Leaver) performLeaveRoomByID(
 	// a leave event.
 	// TODO: Check what happens if the room exists on the server
 	// but everyone has since left. I suspect it does the wrong thing.
-	buildRes := api.QueryLatestEventsAndStateResponse{}
-	event, err := eventutil.BuildEvent(
-		ctx,          // the request context
-		&eb,          // the template leave event
-		r.Cfg.Matrix, // the server configuration
-		time.Now(),   // the event timestamp to use
-		r.RSAPI,      // the roomserver API to use
-		&buildRes,    // the query response
-	)
+	event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
 	if err != nil {
 		return nil, fmt.Errorf("eventutil.BuildEvent: %w", err)
 	}
@@ -135,7 +139,7 @@ func (r *Leaver) performLeaveRoomByID(
 		},
 	}
 	inputRes := api.InputRoomEventsResponse{}
-	if err = r.RSAPI.InputRoomEvents(ctx, &inputReq, &inputRes); err != nil {
+	if err = r.Inputer.InputRoomEvents(ctx, &inputReq, &inputRes); err != nil {
 		return nil, fmt.Errorf("r.InputRoomEvents: %w", err)
 	}
 
diff --git a/roomserver/internal/perform/perform_publish.go b/roomserver/internal/perform/perform_publish.go
index aab282f3..6ff42ac1 100644
--- a/roomserver/internal/perform/perform_publish.go
+++ b/roomserver/internal/perform/perform_publish.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// 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 perform
 
 import (
diff --git a/roomserver/internal/query.go b/roomserver/internal/query/query.go
index 26b22c74..b2799aef 100644
--- a/roomserver/internal/query.go
+++ b/roomserver/internal/query/query.go
@@ -1,6 +1,4 @@
-// Copyright 2017 Vector Creations Ltd
-// Copyright 2018 New Vector Ltd
-// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+// Copyright 2020 The Matrix.org Foundation C.I.C.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -14,15 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package query
 
 import (
 	"context"
 	"fmt"
 
+	"github.com/matrix-org/dendrite/internal/caching"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/internal/helpers"
 	"github.com/matrix-org/dendrite/roomserver/state"
+	"github.com/matrix-org/dendrite/roomserver/storage"
 	"github.com/matrix-org/dendrite/roomserver/types"
 	"github.com/matrix-org/dendrite/roomserver/version"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -30,62 +30,22 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+type Queryer struct {
+	DB    storage.Database
+	Cache caching.RoomServerCaches
+}
+
 // QueryLatestEventsAndState implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryLatestEventsAndState(
+func (r *Queryer) QueryLatestEventsAndState(
 	ctx context.Context,
 	request *api.QueryLatestEventsAndStateRequest,
 	response *api.QueryLatestEventsAndStateResponse,
 ) error {
-	roomInfo, err := r.DB.RoomInfo(ctx, request.RoomID)
-	if err != nil {
-		return err
-	}
-	if roomInfo == nil || roomInfo.IsStub {
-		response.RoomExists = false
-		return nil
-	}
-
-	roomState := state.NewStateResolution(r.DB, *roomInfo)
-	response.RoomExists = true
-	response.RoomVersion = roomInfo.RoomVersion
-
-	var currentStateSnapshotNID types.StateSnapshotNID
-	response.LatestEvents, currentStateSnapshotNID, response.Depth, err =
-		r.DB.LatestEventIDs(ctx, roomInfo.RoomNID)
-	if err != nil {
-		return err
-	}
-
-	var stateEntries []types.StateEntry
-	if len(request.StateToFetch) == 0 {
-		// Look up all room state.
-		stateEntries, err = roomState.LoadStateAtSnapshot(
-			ctx, currentStateSnapshotNID,
-		)
-	} else {
-		// Look up the current state for the requested tuples.
-		stateEntries, err = roomState.LoadStateAtSnapshotForStringTuples(
-			ctx, currentStateSnapshotNID, request.StateToFetch,
-		)
-	}
-	if err != nil {
-		return err
-	}
-
-	stateEvents, err := helpers.LoadStateEvents(ctx, r.DB, stateEntries)
-	if err != nil {
-		return err
-	}
-
-	for _, event := range stateEvents {
-		response.StateEvents = append(response.StateEvents, event.Headered(roomInfo.RoomVersion))
-	}
-
-	return nil
+	return helpers.QueryLatestEventsAndState(ctx, r.DB, request, response)
 }
 
 // QueryStateAfterEvents implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryStateAfterEvents(
+func (r *Queryer) QueryStateAfterEvents(
 	ctx context.Context,
 	request *api.QueryStateAfterEventsRequest,
 	response *api.QueryStateAfterEventsResponse,
@@ -134,7 +94,7 @@ func (r *RoomserverInternalAPI) QueryStateAfterEvents(
 }
 
 // QueryEventsByID implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryEventsByID(
+func (r *Queryer) QueryEventsByID(
 	ctx context.Context,
 	request *api.QueryEventsByIDRequest,
 	response *api.QueryEventsByIDResponse,
@@ -167,7 +127,7 @@ func (r *RoomserverInternalAPI) QueryEventsByID(
 }
 
 // QueryMembershipForUser implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryMembershipForUser(
+func (r *Queryer) QueryMembershipForUser(
 	ctx context.Context,
 	request *api.QueryMembershipForUserRequest,
 	response *api.QueryMembershipForUserResponse,
@@ -204,7 +164,7 @@ func (r *RoomserverInternalAPI) QueryMembershipForUser(
 }
 
 // QueryMembershipsForRoom implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryMembershipsForRoom(
+func (r *Queryer) QueryMembershipsForRoom(
 	ctx context.Context,
 	request *api.QueryMembershipsForRoomRequest,
 	response *api.QueryMembershipsForRoomResponse,
@@ -260,7 +220,7 @@ func (r *RoomserverInternalAPI) QueryMembershipsForRoom(
 }
 
 // QueryServerAllowedToSeeEvent implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryServerAllowedToSeeEvent(
+func (r *Queryer) QueryServerAllowedToSeeEvent(
 	ctx context.Context,
 	request *api.QueryServerAllowedToSeeEventRequest,
 	response *api.QueryServerAllowedToSeeEventResponse,
@@ -293,7 +253,7 @@ func (r *RoomserverInternalAPI) QueryServerAllowedToSeeEvent(
 
 // QueryMissingEvents implements api.RoomserverInternalAPI
 // nolint:gocyclo
-func (r *RoomserverInternalAPI) QueryMissingEvents(
+func (r *Queryer) QueryMissingEvents(
 	ctx context.Context,
 	request *api.QueryMissingEventsRequest,
 	response *api.QueryMissingEventsResponse,
@@ -352,7 +312,7 @@ func (r *RoomserverInternalAPI) QueryMissingEvents(
 }
 
 // QueryStateAndAuthChain implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryStateAndAuthChain(
+func (r *Queryer) QueryStateAndAuthChain(
 	ctx context.Context,
 	request *api.QueryStateAndAuthChainRequest,
 	response *api.QueryStateAndAuthChainResponse,
@@ -405,7 +365,7 @@ func (r *RoomserverInternalAPI) QueryStateAndAuthChain(
 	return err
 }
 
-func (r *RoomserverInternalAPI) loadStateAtEventIDs(ctx context.Context, roomInfo types.RoomInfo, eventIDs []string) ([]gomatrixserverlib.Event, error) {
+func (r *Queryer) loadStateAtEventIDs(ctx context.Context, roomInfo types.RoomInfo, eventIDs []string) ([]gomatrixserverlib.Event, error) {
 	roomState := state.NewStateResolution(r.DB, roomInfo)
 	prevStates, err := r.DB.StateAtEventIDs(ctx, eventIDs)
 	if err != nil {
@@ -482,7 +442,7 @@ func getAuthChain(
 }
 
 // QueryRoomVersionCapabilities implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryRoomVersionCapabilities(
+func (r *Queryer) QueryRoomVersionCapabilities(
 	ctx context.Context,
 	request *api.QueryRoomVersionCapabilitiesRequest,
 	response *api.QueryRoomVersionCapabilitiesResponse,
@@ -500,7 +460,7 @@ func (r *RoomserverInternalAPI) QueryRoomVersionCapabilities(
 }
 
 // QueryRoomVersionCapabilities implements api.RoomserverInternalAPI
-func (r *RoomserverInternalAPI) QueryRoomVersionForRoom(
+func (r *Queryer) QueryRoomVersionForRoom(
 	ctx context.Context,
 	request *api.QueryRoomVersionForRoomRequest,
 	response *api.QueryRoomVersionForRoomResponse,
@@ -522,7 +482,7 @@ func (r *RoomserverInternalAPI) QueryRoomVersionForRoom(
 	return nil
 }
 
-func (r *RoomserverInternalAPI) roomVersion(roomID string) (gomatrixserverlib.RoomVersion, error) {
+func (r *Queryer) roomVersion(roomID string) (gomatrixserverlib.RoomVersion, error) {
 	var res api.QueryRoomVersionForRoomResponse
 	err := r.QueryRoomVersionForRoom(context.Background(), &api.QueryRoomVersionForRoomRequest{
 		RoomID: roomID,
@@ -530,7 +490,7 @@ func (r *RoomserverInternalAPI) roomVersion(roomID string) (gomatrixserverlib.Ro
 	return res.RoomVersion, err
 }
 
-func (r *RoomserverInternalAPI) QueryPublishedRooms(
+func (r *Queryer) QueryPublishedRooms(
 	ctx context.Context,
 	req *api.QueryPublishedRoomsRequest,
 	res *api.QueryPublishedRoomsResponse,
diff --git a/roomserver/internal/query_test.go b/roomserver/internal/query/query_test.go
index 92e00832..b4cb99b8 100644
--- a/roomserver/internal/query_test.go
+++ b/roomserver/internal/query/query_test.go
@@ -1,4 +1,4 @@
-// Copyright 2017 Vector Creations Ltd
+// Copyright 2020 The Matrix.org Foundation C.I.C.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package query
 
 import (
 	"context"