a very very WIP first cut of peeking via MSC2753.

doesn't yet compile or work.
needs to actually add the peeking block into the sync response.
checking in now before it gets any bigger, and to gather any initial feedback on the vague shape of it.

syncapi/storage/interface.go

@@ -30,6 +30,8 @@ type Database interface {
 	internal.PartitionStorer
 	// AllJoinedUsersInRooms returns a map of room ID to a list of all joined user IDs.
 	AllJoinedUsersInRooms(ctx context.Context) (map[string][]string, error)
+	// AllPeekingDevicesInRooms returns a map of room ID to a list of all peeking devices.
+	AllPeekingDevicesInRooms(ctx context.Context) (map[string][]PeekingDevice, error)
 	// Events lookups a list of event by their event ID.
 	// Returns a list of events matching the requested IDs found in the database.
 	// If an event is not found in the database then it will be omitted from the list.

syncapi/storage/shared/syncserver.go

@@ -120,6 +120,10 @@ func (d *Database) AllJoinedUsersInRooms(ctx context.Context) (map[string][]stri
 	return d.CurrentRoomState.SelectJoinedUsers(ctx)
 }
 
+func (d *Database) AllPeekingDevicesInRooms(ctx context.Context) (map[string][]PeekingDevice, error) {
+	return d.Peeks.SelectPeekingDevices(ctx)
+}
+
 func (d *Database) GetStateEvent(
 	ctx context.Context, roomID, evType, stateKey string,
 ) (*gomatrixserverlib.HeaderedEvent, error) {
@@ -187,6 +191,19 @@ func (d *Database) RetireInviteEvent(
 	return
 }
 
+// AddPeek tracks the fact that a user has started peeking.
+// If the peek was successfully stored this returns the stream ID it was stored at.
+// Returns an error if there was a problem communicating with the database.
+func (d *Database) AddPeek(
+	ctx context.Context, roomID, userID, deviceID string,
+) (sp types.StreamPosition, err error) {
+	_ = d.Writer.Do(nil, nil, func(_ *sql.Tx) error {
+		sp, err = d.Peeks.InsertPeek(ctx, nil, inviteEvent)
+		return nil
+	})
+	return
+}
+
 // GetAccountDataInRange returns all account data for a given user inserted or
 // updated between two given positions
 // Returns a map following the format data[roomID] = []dataTypes

syncapi/storage/sqlite3/peeks_table.go

@@ -0,0 +1,151 @@
+// 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const peeksSchema = `
+CREATE TABLE IF NOT EXISTS syncapi_peeks (
+	id INTEGER PRIMARY KEY,
+	room_id TEXT NOT NULL,
+	user_id TEXT NOT NULL,
+	device_id TEXT NOT NULL,
+    -- When the peek was created in UNIX epoch ms.
+    creation_ts INTEGER NOT NULL,
+);
+
+CREATE INDEX IF NOT EXISTS syncapi_peeks_room_id_idx ON syncapi_peeks(room_id);
+CREATE INDEX IF NOT EXISTS syncapi_peeks_user_id_device_id_idx ON syncapi_peeks(user_Id, device_id);
+`
+
+const insertPeekSQL = "" +
+	"INSERT INTO syncapi_peeks" +
+	" (id, room_id, user_id, device_id, creation_ts" +
+	" VALUES ($1, $2, $3, $4, $5)"
+
+const deletePeekSQL = "" +
+	"DELETE FROM syncapi_peeks WHERE room_id = $1 AND user_id = $2 and device_id = $3"
+
+const selectPeeksSQL == "" +
+	"SELECT room_id FROM syncapi_peeks WHERE user_id = $1 and device_id = $2"
+
+const selectPeekingDevicesSQL == "" +
+	"SELECT room_id, user_id, device_id FROM syncapi_peeks"
+
+type peekStatements struct {
+	db                            *sql.DB
+	insertPeekStmt        		  *sql.Stmt
+	deletePeekStmt         		  *sql.Stmt
+	selectPeeksStmt				  *sql.Stmt
+	selectPeekingDevicesStmt	  *sql.Stmt
+}
+
+func NewSqlitePeeksTable(db *sql.DB) (tables.Peeks, error) {
+	_, err := db.Exec(filterSchema)
+	if err != nil {
+		return nil, err
+	}
+	s := &peekStatements{
+		db: db,
+	}
+	if s.insertPeekStmt, err = db.Prepare(insertPeekSQL); err != nil {
+		return nil, err
+	}
+	if s.deletePeekStmt, err = db.Prepare(deletePeekSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPeeksStmt, err = db.Prepare(selectPeeksSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPeekingDevicesStmt, err = db.Prepare(selectPeekingDevicesSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *peekStatements) InsertPeek(
+	ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string,
+) (streamPos types.StreamPosition, err error) {
+	streamPos, err = s.streamIDStatements.nextStreamID(ctx, txn)
+	if err != nil {
+		return
+	}
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	_, err = sqlutil.TxStmt(txn, s.insertPeekStmt).ExecContext(ctx, roomID, userID, deviceID, nowMilli)
+	return
+}
+
+func (s *peekStatements) DeletePeek(
+	ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string,
+) (streamPos types.StreamPosition, err error) {
+	streamPos, err = s.streamIDStatements.nextStreamID(ctx, txn)
+	if err != nil {
+		return
+	}
+	_, err = sqlutil.TxStmt(txn, s.deletePeekStmt).ExecContext(ctx, roomID, userID, deviceID)
+	return
+}
+
+func (s *peekStatements) SelectPeeks(
+	ctx context.Context, txn *sql.Tx, userID, deviceID string,
+) (roomIDs []string, err error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectPeeksStmt).QueryContext(ctx, userID, deviceID)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectPeeks: rows.close() failed")
+
+	for rows.Next() {
+		var roomID string
+		if err = rows.Scan(&roomId); err != nil {
+			return
+		}
+		roomIDs = append(roomIDs, roomID)
+	}
+
+	return roomIDs, rows.Err()
+}
+
+func (s *peekStatements) SelectPeekingDevices(
+	ctx context.Context,
+) (peekingDevices map[string][]PeekingDevice, err error) {
+	rows, err := s.selectPeekingDevicesStmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectPeekingDevices: rows.close() failed")
+
+	result := make(map[string][]PeekingDevice)
+	for rows.Next() {
+		var roomID, userID, deviceID string
+		if err := rows.Scan(&roomID, &userID, &deviceID); err != nil {
+			return nil, err
+		}
+		devices := result[roomID]
+		devices = append(devices, PeekingDevice{userID, deviceID})
+		result[roomID] = devices
+	}
+	return result, nil
+}

syncapi/storage/tables/interface.go

@@ -39,6 +39,13 @@ type Invites interface {
 	SelectMaxInviteID(ctx context.Context, txn *sql.Tx) (id int64, err error)
 }
 
+type Peeks interface {
+	InsertPeek(ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string) (streamPos types.StreamPosition, err error)
+	DeletePeek(ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string) (streamPos types.StreamPosition, err error)
+	SelectPeeks(ctxt context.Context, txn *sql.Tx, userID, deviceID string) (peeks []string, err error)
+	SelectPeekingDevices((ctxt context.Context) (peekingDevices map[string][]PeekingDevice, err error)
+}
+
 type Events interface {
 	SelectStateInRange(ctx context.Context, txn *sql.Tx, r types.Range, stateFilter *gomatrixserverlib.StateFilter) (map[string]map[string]bool, map[string]types.StreamEvent, error)
 	SelectMaxEventID(ctx context.Context, txn *sql.Tx) (id int64, err error)