MSC2946: Spaces Summary (#1700)

* Add stub functions for MSC2946

* Implement core space walking algorithm

* Flesh out stub functions; add test stubs

* Implement storage bits and add sanity check test

* Implement world_readable auth with test

* Linting

setup/mscs/msc2946/storage.go

@@ -0,0 +1,183 @@
+// Copyright 2021 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 msc2946
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/tidwall/gjson"
+)
+
+var (
+	relTypes = map[string]int{
+		ConstSpaceChildEventType:  1,
+		ConstSpaceParentEventType: 2,
+	}
+)
+
+type Database interface {
+	// StoreReference persists a child or parent space mapping.
+	StoreReference(ctx context.Context, he *gomatrixserverlib.HeaderedEvent) error
+	// References returns all events which have the given roomID as a parent or child space.
+	References(ctx context.Context, roomID string) ([]*gomatrixserverlib.HeaderedEvent, error)
+}
+
+type DB struct {
+	db              *sql.DB
+	writer          sqlutil.Writer
+	insertEdgeStmt  *sql.Stmt
+	selectEdgesStmt *sql.Stmt
+}
+
+// NewDatabase loads the database for msc2836
+func NewDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	if dbOpts.ConnectionString.IsPostgres() {
+		return newPostgresDatabase(dbOpts)
+	}
+	return newSQLiteDatabase(dbOpts)
+}
+
+func newPostgresDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	d := DB{
+		writer: sqlutil.NewDummyWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbOpts); err != nil {
+		return nil, err
+	}
+	_, err = d.db.Exec(`
+	CREATE TABLE IF NOT EXISTS msc2946_edges (
+		room_version TEXT NOT NULL,
+		-- the room ID of the event, the source of the arrow
+		source_room_id TEXT NOT NULL,
+		-- the target room ID, the arrow destination
+		dest_room_id TEXT NOT NULL,
+		-- the kind of relation, either child or parent (1,2)
+		rel_type SMALLINT NOT NULL,
+		event_json TEXT NOT NULL,
+		CONSTRAINT msc2946_edges_uniq UNIQUE (source_room_id, dest_room_id, rel_type)
+	);
+	`)
+	if err != nil {
+		return nil, err
+	}
+	if d.insertEdgeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2946_edges(room_version, source_room_id, dest_room_id, rel_type, event_json)
+		VALUES($1, $2, $3, $4, $5)
+		ON CONFLICT DO NOTHING
+	`); err != nil {
+		return nil, err
+	}
+	if d.selectEdgesStmt, err = d.db.Prepare(`
+		SELECT room_version, event_json FROM msc2946_edges
+		WHERE source_room_id = $1 OR dest_room_id = $2
+	`); err != nil {
+		return nil, err
+	}
+	return &d, err
+}
+
+func newSQLiteDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	d := DB{
+		writer: sqlutil.NewExclusiveWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbOpts); err != nil {
+		return nil, err
+	}
+	_, err = d.db.Exec(`
+	CREATE TABLE IF NOT EXISTS msc2946_edges (
+		room_version TEXT NOT NULL,
+		-- the room ID of the event, the source of the arrow
+		source_room_id TEXT NOT NULL,
+		-- the target room ID, the arrow destination
+		dest_room_id TEXT NOT NULL,
+		-- the kind of relation, either child or parent (1,2)
+		rel_type SMALLINT NOT NULL,
+		event_json TEXT NOT NULL,
+		UNIQUE (source_room_id, dest_room_id, rel_type)
+	);
+	`)
+	if err != nil {
+		return nil, err
+	}
+	if d.insertEdgeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2946_edges(room_version, source_room_id, dest_room_id, rel_type, event_json)
+		VALUES($1, $2, $3, $4, $5)
+		ON CONFLICT DO NOTHING
+	`); err != nil {
+		return nil, err
+	}
+	if d.selectEdgesStmt, err = d.db.Prepare(`
+		SELECT room_version, event_json FROM msc2946_edges
+		WHERE source_room_id = $1 OR dest_room_id = $2
+	`); err != nil {
+		return nil, err
+	}
+	return &d, err
+}
+
+func (d *DB) StoreReference(ctx context.Context, he *gomatrixserverlib.HeaderedEvent) error {
+	target := SpaceTarget(he)
+	if target == "" {
+		return nil // malformed event
+	}
+	relType := relTypes[he.Type()]
+	_, err := d.insertEdgeStmt.ExecContext(ctx, he.RoomVersion, he.RoomID(), target, relType, he.JSON())
+	return err
+}
+
+func (d *DB) References(ctx context.Context, roomID string) ([]*gomatrixserverlib.HeaderedEvent, error) {
+	rows, err := d.selectEdgesStmt.QueryContext(ctx, roomID, roomID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "failed to close References")
+	refs := make([]*gomatrixserverlib.HeaderedEvent, 0)
+	for rows.Next() {
+		var roomVer string
+		var jsonBytes []byte
+		if err := rows.Scan(&roomVer, &jsonBytes); err != nil {
+			return nil, err
+		}
+		ev, err := gomatrixserverlib.NewEventFromTrustedJSON(jsonBytes, false, gomatrixserverlib.RoomVersion(roomVer))
+		if err != nil {
+			return nil, err
+		}
+		he := ev.Headered(gomatrixserverlib.RoomVersion(roomVer))
+		refs = append(refs, he)
+	}
+	return refs, nil
+}
+
+// SpaceTarget returns the destination room ID for the space event. This is either a child or a parent
+// depending on the event type.
+func SpaceTarget(he *gomatrixserverlib.HeaderedEvent) string {
+	if he.StateKey() == nil {
+		return "" // no-op
+	}
+	switch he.Type() {
+	case ConstSpaceParentEventType:
+		return gjson.GetBytes(he.Content(), "room_id").Str
+	case ConstSpaceChildEventType:
+		return *he.StateKey()
+	}
+	return ""
+}