Peeking via MSC2753 (#1370)

Initial implementation of MSC2753, as tested by https://github.com/matrix-org/sytest/pull/944.
Doesn't yet handle unpeeks, peeked EDUs, or history viz changing during a peek - these will follow.
https://github.com/matrix-org/dendrite/pull/1370 has full details.

2 files changed, 191 insertions, 0 deletions

diff --git a/syncapi/storage/postgres/peeks_table.go b/syncapi/storage/postgres/peeks_table.go
new file mode 100644
index 00000000..75eeac98
--- /dev/null
+++ b/syncapi/storage/postgres/peeks_table.go
@@ -0,0 +1,186 @@
+// 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 postgres
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"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"
+)
+
+const peeksSchema = `
+CREATE TABLE IF NOT EXISTS syncapi_peeks (
+	id BIGINT DEFAULT nextval('syncapi_stream_id'),
+	room_id TEXT NOT NULL,
+	user_id TEXT NOT NULL,
+	device_id TEXT NOT NULL,
+	deleted BOOL NOT NULL DEFAULT false,
+    -- When the peek was created in UNIX epoch ms.
+    creation_ts BIGINT NOT NULL,
+    UNIQUE(room_id, user_id, device_id)
+);
+
+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" +
+	" (room_id, user_id, device_id, creation_ts)" +
+	" VALUES ($1, $2, $3, $4)" +
+	" ON CONFLICT (room_id, user_id, device_id) DO UPDATE SET deleted=false, creation_ts=$4" +
+	" RETURNING id"
+
+const deletePeekSQL = "" +
+	"UPDATE syncapi_peeks SET deleted=true, id=nextval('syncapi_stream_id') WHERE room_id = $1 AND user_id = $2 AND device_id = $3 RETURNING id"
+
+const deletePeeksSQL = "" +
+	"UPDATE syncapi_peeks SET deleted=true, id=nextval('syncapi_stream_id') WHERE room_id = $1 AND user_id = $2 RETURNING id"
+
+// we care about all the peeks which were created in this range, deleted in this range,
+// or were created before this range but haven't been deleted yet.
+const selectPeeksInRangeSQL = "" +
+	"SELECT room_id, deleted, (id > $3 AND id <= $4) AS changed FROM syncapi_peeks WHERE user_id = $1 AND device_id = $2 AND ((id <= $3 AND NOT deleted) OR (id > $3 AND id <= $4))"
+
+const selectPeekingDevicesSQL = "" +
+	"SELECT room_id, user_id, device_id FROM syncapi_peeks WHERE deleted=false"
+
+const selectMaxPeekIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_peeks"
+
+type peekStatements struct {
+	db                       *sql.DB
+	insertPeekStmt           *sql.Stmt
+	deletePeekStmt           *sql.Stmt
+	deletePeeksStmt          *sql.Stmt
+	selectPeeksInRangeStmt   *sql.Stmt
+	selectPeekingDevicesStmt *sql.Stmt
+	selectMaxPeekIDStmt      *sql.Stmt
+}
+
+func NewPostgresPeeksTable(db *sql.DB) (tables.Peeks, error) {
+	_, err := db.Exec(peeksSchema)
+	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.deletePeeksStmt, err = db.Prepare(deletePeeksSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPeeksInRangeStmt, err = db.Prepare(selectPeeksInRangeSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPeekingDevicesStmt, err = db.Prepare(selectPeekingDevicesSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxPeekIDStmt, err = db.Prepare(selectMaxPeekIDSQL); 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) {
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	stmt := sqlutil.TxStmt(txn, s.insertPeekStmt)
+	err = stmt.QueryRowContext(ctx, roomID, userID, deviceID, nowMilli).Scan(&streamPos)
+	return
+}
+
+func (s *peekStatements) DeletePeek(
+	ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string,
+) (streamPos types.StreamPosition, err error) {
+	stmt := sqlutil.TxStmt(txn, s.deletePeekStmt)
+	err = stmt.QueryRowContext(ctx, roomID, userID, deviceID).Scan(&streamPos)
+	return
+}
+
+func (s *peekStatements) DeletePeeks(
+	ctx context.Context, txn *sql.Tx, roomID, userID string,
+) (streamPos types.StreamPosition, err error) {
+	stmt := sqlutil.TxStmt(txn, s.deletePeeksStmt)
+	err = stmt.QueryRowContext(ctx, roomID, userID).Scan(&streamPos)
+	return
+}
+
+func (s *peekStatements) SelectPeeksInRange(
+	ctx context.Context, txn *sql.Tx, userID, deviceID string, r types.Range,
+) (peeks []types.Peek, err error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectPeeksInRangeStmt).QueryContext(ctx, userID, deviceID, r.Low(), r.High())
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectPeeksInRange: rows.close() failed")
+
+	for rows.Next() {
+		peek := types.Peek{}
+		var changed bool
+		if err = rows.Scan(&peek.RoomID, &peek.Deleted, &changed); err != nil {
+			return
+		}
+		peek.New = changed && !peek.Deleted
+		peeks = append(peeks, peek)
+	}
+
+	return peeks, rows.Err()
+}
+
+func (s *peekStatements) SelectPeekingDevices(
+	ctx context.Context,
+) (peekingDevices map[string][]types.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][]types.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, types.PeekingDevice{UserID: userID, DeviceID: deviceID})
+		result[roomID] = devices
+	}
+	return result, nil
+}
+
+func (s *peekStatements) SelectMaxPeekID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxPeekIDStmt)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}
diff --git a/syncapi/storage/postgres/syncserver.go b/syncapi/storage/postgres/syncserver.go
index e7f2c944..7f19722a 100644
--- a/syncapi/storage/postgres/syncserver.go
+++ b/syncapi/storage/postgres/syncserver.go
@@ -62,6 +62,10 @@ func NewDatabase(dbProperties *config.DatabaseOptions) (*SyncServerDatasource, e
 	if err != nil {
 		return nil, err
 	}
+	peeks, err := NewPostgresPeeksTable(d.db)
+	if err != nil {
+		return nil, err
+	}
 	topology, err := NewPostgresTopologyTable(d.db)
 	if err != nil {
 		return nil, err
@@ -82,6 +86,7 @@ func NewDatabase(dbProperties *config.DatabaseOptions) (*SyncServerDatasource, e
 		DB:                  d.db,
 		Writer:              d.writer,
 		Invites:             invites,
+		Peeks:               peeks,
 		AccountData:         accountData,
 		OutputEvents:        events,
 		Topology:            topology,