From 19f1a6fe0d543ab5f8b95de3883591235dfdeb8f Mon Sep 17 00:00:00 2001
From: Cnly <minecnly@gmail.com>
Date: Thu, 27 Jun 2019 16:11:29 +0800
Subject: [PATCH] Remove users from typing list when typing status times out

Signed-off-by: Alex Chen <minecnly@gmail.com>
---
 syncapi/consumers/typingserver.go |  6 ++++++
 syncapi/storage/syncserver.go     |  4 ++++
 typingserver/cache/cache.go       | 28 ++++++++++++++++++----------
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/syncapi/consumers/typingserver.go b/syncapi/consumers/typingserver.go
index 5efb14faf..601ebaabd 100644
--- a/syncapi/consumers/typingserver.go
+++ b/syncapi/consumers/typingserver.go
@@ -45,11 +45,13 @@ func NewOutputTypingEventConsumer(
 		Consumer:       kafkaConsumer,
 		PartitionStore: store,
 	}
+
 	s := &OutputTypingEventConsumer{
 		typingConsumer: &consumer,
 		db:             store,
 		notifier:       n,
 	}
+
 	consumer.ProcessMessage = s.onMessage
 
 	return s
@@ -57,6 +59,10 @@ func NewOutputTypingEventConsumer(
 
 // Start consuming from typing api
 func (s *OutputTypingEventConsumer) Start() error {
+	s.db.SetTypingTimeoutCallback(func(userID, roomID string, latestSyncPosition int64) {
+		s.notifier.OnNewEvent(nil, roomID, nil, types.SyncPosition{TypingPosition: latestSyncPosition})
+	})
+
 	return s.typingConsumer.Start()
 }
 
diff --git a/syncapi/storage/syncserver.go b/syncapi/storage/syncserver.go
index 4b85cafdc..e76a38e0d 100644
--- a/syncapi/storage/syncserver.go
+++ b/syncapi/storage/syncserver.go
@@ -515,6 +515,10 @@ func (d *SyncServerDatasource) RetireInviteEvent(
 	return err
 }
 
+func (d *SyncServerDatasource) SetTypingTimeoutCallback(fn cache.TimeoutCallbackFn) {
+	d.typingCache.SetTimeoutCallback(fn)
+}
+
 // AddTypingUser adds a typing user to the typing cache.
 // Returns the latest sync position for typing notifications after update.
 func (d *SyncServerDatasource) AddTypingUser(
diff --git a/typingserver/cache/cache.go b/typingserver/cache/cache.go
index 356228a0d..2571e7427 100644
--- a/typingserver/cache/cache.go
+++ b/typingserver/cache/cache.go
@@ -22,6 +22,11 @@ const defaultTypingTimeout = 10 * time.Second
 // userSet is a map of user IDs to a timer, timer fires at expiry.
 type userSet map[string]*time.Timer
 
+// TimeoutCallbackFn is a function called right after removal of a user
+// from the typing user list due to timeout.
+// latestSyncPosition is the typing sync position after the removal.
+type TimeoutCallbackFn func(userID, roomID string, latestSyncPosition int64)
+
 type roomData struct {
 	syncPosition int64
 	userSet      userSet
@@ -32,6 +37,7 @@ type TypingCache struct {
 	sync.RWMutex
 	latestSyncPosition int64
 	data               map[string]*roomData
+	timeoutCallback    TimeoutCallbackFn
 }
 
 // Create a roomData with its sync position set to the latest sync position.
@@ -48,6 +54,12 @@ func NewTypingCache() *TypingCache {
 	return &TypingCache{data: make(map[string]*roomData)}
 }
 
+// SetTimeoutCallback sets a callback function that is called right after
+// a user is removed from the typing user list due to timeout.
+func (t *TypingCache) SetTimeoutCallback(fn TimeoutCallbackFn) {
+	t.timeoutCallback = fn
+}
+
 // GetTypingUsers returns the list of users typing in a room.
 func (t *TypingCache) GetTypingUsers(roomID string) []string {
 	users, _ := t.GetTypingUsersIfUpdatedAfter(roomID, 0)
@@ -86,7 +98,12 @@ func (t *TypingCache) AddTypingUser(
 ) int64 {
 	expireTime := getExpireTime(expire)
 	if until := time.Until(expireTime); until > 0 {
-		timer := time.AfterFunc(until, t.timeoutCallback(userID, roomID))
+		timer := time.AfterFunc(until, func() {
+			latestSyncPosition := t.RemoveUser(userID, roomID)
+			if t.timeoutCallback != nil {
+				t.timeoutCallback(userID, roomID, latestSyncPosition)
+			}
+		})
 		return t.addUser(userID, roomID, timer)
 	}
 	return t.GetLatestSyncPosition()
@@ -123,15 +140,6 @@ func (t *TypingCache) addUser(
 	return t.latestSyncPosition
 }
 
-// Returns a function which is called after timeout happens.
-// This removes the user.
-func (t *TypingCache) timeoutCallback(userID, roomID string) func() {
-	return func() {
-		// TODO: Notify syncing users about removal
-		t.RemoveUser(userID, roomID)
-	}
-}
-
 // RemoveUser with mutex lock & stop the timer.
 // Returns the latest sync position for typing after update.
 func (t *TypingCache) RemoveUser(userID, roomID string) int64 {