CODEWITHSUNDEEP
c#multithreadinglockingnested
Robert Harvey
Robert Harvey

Reputation: 180808

How do I safely lock this property?

I have partial C# code for a blocking queue that looks like this:

private bool flushed;
private object _locker = new object();

public bool Flushed
{
    get { lock (_locker) { return flushed; } }
    set
    {
        lock (_locker)
        {
            flushed = value;
            Monitor.Pulse(queue);
        }
    }
}

The Monitor.Pulse method has a Monitor.Wait counterpart in the Dequeue() method of the blocking queue.

I want to add a method that signals end of data, which checks for the Flush condition. It will look something like this:

public bool EndOfData
{
    get { lock (_locker) { return Flushed && (queue.Count == 0); } }
}

Here is my question. Should I call the Flushed property as shown in the code above (taking a nested lock), or is it sufficient to refer to the private member variable flushed directly, as shown below, using only a single lock?

public bool EndOfData
{
    get { lock (_locker) { return flushed && (queue.Count == 0); } }
}

Upvotes: 3

Views: 153

Answers (1)

JonH
JonH

Reputation: 33153

I don't think it makes a difference, personally I would use the nested version. I think if anything changes in the actual property by using it, Flushed, you ensure that everything is good to go.

But I truly believe this is a preference call.

Upvotes: 2

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