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-rw-r--r--Emby.Server.Implementations/SyncPlay/Group.cs18
-rw-r--r--Emby.Server.Implementations/SyncPlay/SyncPlayManager.cs13
2 files changed, 24 insertions, 7 deletions
diff --git a/Emby.Server.Implementations/SyncPlay/Group.cs b/Emby.Server.Implementations/SyncPlay/Group.cs
index 38a0018a70..923bfc67aa 100644
--- a/Emby.Server.Implementations/SyncPlay/Group.cs
+++ b/Emby.Server.Implementations/SyncPlay/Group.cs
@@ -91,6 +91,18 @@ namespace Emby.Server.Implementations.SyncPlay
public long DefaultPing { get; } = 500;
/// <summary>
+ /// Gets the maximum ping, in milliseconds, accepted from a session.
+ /// </summary>
+ /// <remarks>
+ /// Pings are reported by clients and are scaled into the delays used to schedule playback,
+ /// so an unbounded value lets a single session push the whole group's resume point
+ /// arbitrarily far out, or overflow the arithmetic entirely. Anything above this is not a
+ /// usable measurement for synchronisation.
+ /// </remarks>
+ /// <value>The maximum ping.</value>
+ public long MaxPing { get; } = 10000;
+
+ /// <summary>
/// Gets the maximum time offset error accepted for dates reported by clients, in milliseconds.
/// </summary>
/// <value>The maximum time offset error.</value>
@@ -438,7 +450,7 @@ namespace Emby.Server.Implementations.SyncPlay
{
if (_participants.TryGetValue(session.Id, out GroupMember value))
{
- value.Ping = ping;
+ value.Ping = Math.Clamp(ping, 0, MaxPing);
}
}
@@ -451,7 +463,9 @@ namespace Emby.Server.Implementations.SyncPlay
max = Math.Max(max, session.Ping);
}
- return max;
+ // A group with no participants has no ping to report. Returning long.MinValue would
+ // overflow the callers that scale this value into ticks, so fall back to the default.
+ return max == long.MinValue ? DefaultPing : max;
}
/// <inheritdoc />
diff --git a/Emby.Server.Implementations/SyncPlay/SyncPlayManager.cs b/Emby.Server.Implementations/SyncPlay/SyncPlayManager.cs
index b45d754554..b88ee33358 100644
--- a/Emby.Server.Implementations/SyncPlay/SyncPlayManager.cs
+++ b/Emby.Server.Implementations/SyncPlay/SyncPlayManager.cs
@@ -181,8 +181,8 @@ namespace Emby.Server.Implementations.SyncPlay
{
if (existingGroup.GroupId.Equals(request.GroupId))
{
- // Restore session.
- UpdateSessionsCounter(session.UserId, 1);
+ // Restore session. The session is already in the group and has already
+ // been counted, so the counter must not be incremented a second time.
group.SessionJoin(session, request, cancellationToken);
return;
}
@@ -332,8 +332,11 @@ namespace Emby.Server.Implementations.SyncPlay
// Group lock required as Group is not thread-safe.
lock (group)
{
- // Make sure that session still belongs to this group.
- if (_sessionToGroupMap.TryGetValue(session.Id, out var checkGroup) && !checkGroup.GroupId.Equals(group.GroupId))
+ // Make sure that session still belongs to this group. The lookup can fail
+ // outright when the session left while this request was waiting on the group
+ // lock, which is exactly the case this re-check exists to catch.
+ if (!_sessionToGroupMap.TryGetValue(session.Id, out var checkGroup)
+ || !checkGroup.GroupId.Equals(group.GroupId))
{
// Drop request.
return;
@@ -400,7 +403,7 @@ namespace Emby.Server.Implementations.SyncPlay
// Update sessions counter.
var newSessionsCounter = _activeUsers.AddOrUpdate(
userId,
- 1,
+ toAdd,
(_, sessionsCounter) => sessionsCounter + toAdd);
// Should never happen.