internal Task <NpgsqlConnector> Allocate(NpgsqlConnection conn, NpgsqlTimeout timeout, bool async, CancellationToken cancellationToken)
{
Monitor.Enter(this);
while (Idle.Count > 0)
{
var connector = Idle.Pop();
// An idle connector could be broken because of a keepalive
if (connector.IsBroken)
{
continue;
}
connector.Connection = conn;
IncrementBusy();
EnsurePruningTimerState();
Monitor.Exit(this);
return(Task.FromResult <NpgsqlConnector>(connector));
}
// No idle connectors available. Have to actually open a new connector or wait for one.
return(AllocateLong(conn, timeout, async, cancellationToken));
}
internal async Task <NpgsqlConnector> AllocateLong(NpgsqlConnection conn, NpgsqlTimeout timeout, bool async, CancellationToken cancellationToken)
{
Debug.Assert(Monitor.IsEntered(this));
NpgsqlConnector connector;
Debug.Assert(Busy <= _max);
if (Busy == _max)
{
// TODO: Async cancellation
var tcs = new TaskCompletionSource <NpgsqlConnector>();
_waiting.Enqueue(new WaitingOpenAttempt {
TaskCompletionSource = tcs, IsAsync = async
});
Monitor.Exit(this);
try
{
if (async)
{
if (timeout.IsSet)
{
var timeLeft = timeout.TimeLeft;
if (timeLeft <= TimeSpan.Zero || tcs.Task != await Task.WhenAny(tcs.Task, Task.Delay(timeLeft)))
{
throw new NpgsqlException($"The connection pool has been exhausted, either raise MaxPoolSize (currently {_max}) or Timeout (currently {Settings.Timeout} seconds)");
}
}
else
{
await tcs.Task;
}
}
else
{
if (timeout.IsSet)
{
var timeLeft = timeout.TimeLeft;
if (timeLeft <= TimeSpan.Zero || !tcs.Task.Wait(timeLeft))
{
throw new NpgsqlException($"The connection pool has been exhausted, either raise MaxPoolSize (currently {_max}) or Timeout (currently {Settings.Timeout} seconds)");
}
}
else
{
tcs.Task.Wait();
}
}
}
catch
{
// We're here if the timeout expired or the cancellation token was triggered
// Re-lock and check in case the task was set to completed after coming out of the Wait
lock (this)
{
if (!tcs.Task.IsCompleted)
{
tcs.SetCanceled();
throw;
}
}
}
connector = tcs.Task.Result;
connector.Connection = conn;
return(connector);
}
// No idle connectors are available, and we're under the pool's maximum capacity.
IncrementBusy();
Monitor.Exit(this);
try
{
connector = new NpgsqlConnector(conn)
{
ClearCounter = _clearCounter
};
await connector.Open(timeout, async, cancellationToken);
Counters.NumberOfPooledConnections.Increment();
EnsureMinPoolSize(conn);
return(connector);
}
catch
{
lock (this)
DecrementBusy();
throw;
}
}
internal static Task WithCancellationAndTimeout(this Task task, NpgsqlTimeout timeout, CancellationToken cancellationToken)
{
return(task
.WithCancellation(cancellationToken)
.WithTimeout(timeout));
}