abstract class ConnectorSource

{

internal NpgsqlConnectionStringBuilder Settings { get; }

/// <summary>

/// Contains the connection string returned to the user from <see cref="NpgsqlConnection.ConnectionString"/>

/// after the connection has been opened. Does not contain the password unless Persist Security Info=true.

/// </summary>

internal string UserFacingConnectionString { get; }

// Note that while the dictionary is protected by locking, we assume that the lists it contains don't need to be

// (i.e. access to connectors of a specific transaction won't be concurrent)

protected readonly Dictionary<Transaction, List<NpgsqlConnector>> _pendingEnlistedConnectors

= new();

internal abstract (int Total, int Idle, int Busy) Statistics { get; }

internal ConnectorSource(NpgsqlConnectionStringBuilder settings, string connString)

{

Settings = settings;

UserFacingConnectionString = settings.PersistSecurityInfo

? connString

: settings.ToStringWithoutPassword();

}

internal abstract ValueTask<NpgsqlConnector> Get(

NpgsqlConnection conn, NpgsqlTimeout timeout, bool async, CancellationToken cancellationToken);

internal abstract void Return(NpgsqlConnector connector);

internal abstract void Clear();

#region Pending Enlisted Connections

internal virtual void AddPendingEnlistedConnector(NpgsqlConnector connector, Transaction transaction)

{

lock (_pendingEnlistedConnectors)

{

if (!_pendingEnlistedConnectors.TryGetValue(transaction, out var list))

list = _pendingEnlistedConnectors[transaction] = new List<NpgsqlConnector>();

list.Add(connector);

}

}

internal virtual void TryRemovePendingEnlistedConnector(NpgsqlConnector connector, Transaction transaction)

{

lock (_pendingEnlistedConnectors)

{

if (!_pendingEnlistedConnectors.TryGetValue(transaction, out var list))

return;

list.Remove(connector);

if (list.Count == 0)

_pendingEnlistedConnectors.Remove(transaction);

}

}

internal virtual bool TryRentEnlistedPending(Transaction transaction, NpgsqlConnection connection,

[NotNullWhen(true)] out NpgsqlConnector? connector)

{

lock (_pendingEnlistedConnectors)

{

if (!_pendingEnlistedConnectors.TryGetValue(transaction, out var list))

{

connector = null;

return false;

}

connector = list[list.Count - 1];

list.RemoveAt(list.Count - 1);

if (list.Count == 0)

_pendingEnlistedConnectors.Remove(transaction);

return true;

}

}

#endregion

}