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.

roomserver/internal/query/query_test.go

@@ -0,0 +1,157 @@
+// 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 query
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+
+	"github.com/matrix-org/dendrite/internal/test"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// used to implement RoomserverInternalAPIEventDB to test getAuthChain
+type getEventDB struct {
+	eventMap map[string]gomatrixserverlib.Event
+}
+
+func createEventDB() *getEventDB {
+	return &getEventDB{
+		eventMap: make(map[string]gomatrixserverlib.Event),
+	}
+}
+
+// Adds a fake event to the storage with given auth events.
+func (db *getEventDB) addFakeEvent(eventID string, authIDs []string) error {
+	authEvents := []gomatrixserverlib.EventReference{}
+	for _, authID := range authIDs {
+		authEvents = append(authEvents, gomatrixserverlib.EventReference{
+			EventID: authID,
+		})
+	}
+
+	builder := map[string]interface{}{
+		"event_id":    eventID,
+		"auth_events": authEvents,
+	}
+
+	eventJSON, err := json.Marshal(&builder)
+	if err != nil {
+		return err
+	}
+
+	event, err := gomatrixserverlib.NewEventFromTrustedJSON(
+		eventJSON, false, gomatrixserverlib.RoomVersionV1,
+	)
+	if err != nil {
+		return err
+	}
+
+	db.eventMap[eventID] = event
+
+	return nil
+}
+
+// Adds multiple events at once, each entry in the map is an eventID and set of
+// auth events that are converted to an event and added.
+func (db *getEventDB) addFakeEvents(graph map[string][]string) error {
+	for eventID, authIDs := range graph {
+		err := db.addFakeEvent(eventID, authIDs)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// EventsFromIDs implements RoomserverInternalAPIEventDB
+func (db *getEventDB) EventsFromIDs(ctx context.Context, eventIDs []string) (res []types.Event, err error) {
+	for _, evID := range eventIDs {
+		res = append(res, types.Event{
+			EventNID: 0,
+			Event:    db.eventMap[evID],
+		})
+	}
+
+	return
+}
+
+func TestGetAuthChainSingle(t *testing.T) {
+	db := createEventDB()
+
+	err := db.addFakeEvents(map[string][]string{
+		"a": {},
+		"b": {"a"},
+		"c": {"a", "b"},
+		"d": {"b", "c"},
+		"e": {"a", "d"},
+	})
+
+	if err != nil {
+		t.Fatalf("Failed to add events to db: %v", err)
+	}
+
+	result, err := getAuthChain(context.TODO(), db.EventsFromIDs, []string{"e"})
+	if err != nil {
+		t.Fatalf("getAuthChain failed: %v", err)
+	}
+
+	var returnedIDs []string
+	for _, event := range result {
+		returnedIDs = append(returnedIDs, event.EventID())
+	}
+
+	expectedIDs := []string{"a", "b", "c", "d", "e"}
+
+	if !test.UnsortedStringSliceEqual(expectedIDs, returnedIDs) {
+		t.Fatalf("returnedIDs got '%v', expected '%v'", returnedIDs, expectedIDs)
+	}
+}
+
+func TestGetAuthChainMultiple(t *testing.T) {
+	db := createEventDB()
+
+	err := db.addFakeEvents(map[string][]string{
+		"a": {},
+		"b": {"a"},
+		"c": {"a", "b"},
+		"d": {"b", "c"},
+		"e": {"a", "d"},
+		"f": {"a", "b", "c"},
+	})
+
+	if err != nil {
+		t.Fatalf("Failed to add events to db: %v", err)
+	}
+
+	result, err := getAuthChain(context.TODO(), db.EventsFromIDs, []string{"e", "f"})
+	if err != nil {
+		t.Fatalf("getAuthChain failed: %v", err)
+	}
+
+	var returnedIDs []string
+	for _, event := range result {
+		returnedIDs = append(returnedIDs, event.EventID())
+	}
+
+	expectedIDs := []string{"a", "b", "c", "d", "e", "f"}
+
+	if !test.UnsortedStringSliceEqual(expectedIDs, returnedIDs) {
+		t.Fatalf("returnedIDs got '%v', expected '%v'", returnedIDs, expectedIDs)
+	}
+}