From 9f834726cdd8f53da49bfea0bd67fb3b58e24771 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Mon, 1 Jun 2020 17:02:48 +0100
Subject: [PATCH] Constructor for TransactionWriter

---
 internal/sql.go                        | 9 ++++++++-
 syncapi/storage/postgres/syncserver.go | 1 +
 syncapi/storage/shared/syncserver.go   | 2 +-
 syncapi/storage/sqlite3/syncserver.go  | 1 +
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/internal/sql.go b/internal/sql.go
index 4abab4d35..546954bd5 100644
--- a/internal/sql.go
+++ b/internal/sql.go
@@ -18,6 +18,7 @@ package internal
 
 import (
 	"database/sql"
+	"errors"
 	"fmt"
 	"runtime"
 	"time"
@@ -120,6 +121,12 @@ type TransactionWriter struct {
 	todo    chan transactionWriterTask
 }
 
+func NewTransactionWriter() *TransactionWriter {
+	return &TransactionWriter{
+		todo: make(chan transactionWriterTask),
+	}
+}
+
 // transactionWriterTask represents a specific task.
 type transactionWriterTask struct {
 	db   *sql.DB
@@ -132,7 +139,7 @@ type transactionWriterTask struct {
 // database parameter. This will block until the task is finished.
 func (w *TransactionWriter) Do(db *sql.DB, f func(txn *sql.Tx) error) error {
 	if w.todo == nil {
-		w.todo = make(chan transactionWriterTask)
+		return errors.New("not initialised")
 	}
 	if !w.running.Load() {
 		go w.run()
diff --git a/syncapi/storage/postgres/syncserver.go b/syncapi/storage/postgres/syncserver.go
index 3684b7ed1..8a8f964a5 100644
--- a/syncapi/storage/postgres/syncserver.go
+++ b/syncapi/storage/postgres/syncserver.go
@@ -82,6 +82,7 @@ func NewDatabase(dbDataSourceName string, dbProperties internal.DbProperties) (*
 		CurrentRoomState:    currState,
 		BackwardExtremities: backwardExtremities,
 		SendToDevice:        sendToDevice,
+		SendToDeviceWriter:  internal.NewTransactionWriter(),
 		EDUCache:            cache.New(),
 	}
 	return &d, nil
diff --git a/syncapi/storage/shared/syncserver.go b/syncapi/storage/shared/syncserver.go
index d160f7f6c..497c043a6 100644
--- a/syncapi/storage/shared/syncserver.go
+++ b/syncapi/storage/shared/syncserver.go
@@ -42,7 +42,7 @@ type Database struct {
 	CurrentRoomState    tables.CurrentRoomState
 	BackwardExtremities tables.BackwardsExtremities
 	SendToDevice        tables.SendToDevice
-	SendToDeviceWriter  internal.TransactionWriter
+	SendToDeviceWriter  *internal.TransactionWriter
 	EDUCache            *cache.EDUCache
 }
 
diff --git a/syncapi/storage/sqlite3/syncserver.go b/syncapi/storage/sqlite3/syncserver.go
index de8730a16..5ba07617e 100644
--- a/syncapi/storage/sqlite3/syncserver.go
+++ b/syncapi/storage/sqlite3/syncserver.go
@@ -108,6 +108,7 @@ func (d *SyncServerDatasource) prepare() (err error) {
 		CurrentRoomState:    roomState,
 		Topology:            topology,
 		SendToDevice:        sendToDevice,
+		SendToDeviceWriter:  internal.NewTransactionWriter(),
 		EDUCache:            cache.New(),
 	}
 	return nil