using System;

using System.Collections.Generic;

using System.Data.Common;

using System.Diagnostics;

using System.Diagnostics.CodeAnalysis;

using System.Net.Security;

using System.Security.Cryptography.X509Certificates;

using System.Threading;

using System.Threading.Tasks;

using System.Transactions;

using Microsoft.Extensions.Logging;

using Npgsql.Internal;

using Npgsql.Internal.ResolverFactories;

using Npgsql.Properties;

using Npgsql.Util;

namespace Npgsql;

public abstract class NpgsqlDataSource : DbDataSource

/// <inheritdoc />

public override string ConnectionString { 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 NpgsqlConnectionStringBuilder Settings { get; }

internal NpgsqlDataSourceConfiguration Configuration { get; }

internal NpgsqlLoggingConfiguration LoggingConfiguration { get; }

readonly PgTypeInfoResolverChain _resolverChain;

internal PgSerializerOptions SerializerOptions { get; private set; } = null!; // Initialized at bootstrapping

/// <summary>

/// Information about PostgreSQL and PostgreSQL-like databases (e.g. type definitions, capabilities...).

/// </summary>

internal NpgsqlDatabaseInfo DatabaseInfo { get; private set; } = null!; // Initialized at bootstrapping

internal TransportSecurityHandler TransportSecurityHandler { get; }

internal RemoteCertificateValidationCallback? UserCertificateValidationCallback { get; }

internal Action<X509CertificateCollection>? ClientCertificatesCallback { get; }

readonly Func<NpgsqlConnectionStringBuilder, string>? _passwordProvider;

readonly Func<NpgsqlConnectionStringBuilder, CancellationToken, ValueTask<string>>? _passwordProviderAsync;

readonly Func<NpgsqlConnectionStringBuilder, CancellationToken, ValueTask<string>>? _periodicPasswordProvider;

readonly TimeSpan _periodicPasswordSuccessRefreshInterval, _periodicPasswordFailureRefreshInterval;

internal IntegratedSecurityHandler IntegratedSecurityHandler { get; }

internal Action<NpgsqlConnection>? ConnectionInitializer { get; }

internal Func<NpgsqlConnection, Task>? ConnectionInitializerAsync { get; }

readonly Timer? _periodicPasswordProviderTimer;

readonly CancellationTokenSource? _timerPasswordProviderCancellationTokenSource;

readonly Task _passwordRefreshTask = null!;

string? _password;

internal bool IsBootstrapped { get; private set; }

volatile DatabaseStateInfo _databaseStateInfo = new();

// 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)

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

= new();

internal MetricsReporter MetricsReporter { get; }

internal string Name { get; }

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

volatile int _isDisposed;

readonly ILogger _connectionLogger;

/// <summary>

/// Semaphore to ensure we don't perform type loading and mapping setup concurrently for this data source.

/// </summary>

readonly SemaphoreSlim _setupMappingsSemaphore = new(1);

readonly INpgsqlNameTranslator _defaultNameTranslator;

internal List<HackyEnumTypeMapping>? _hackyEnumTypeMappings;

internal NpgsqlDataSource(

}

/// <inheritdoc cref="DbDataSource.CreateConnection" />

public new NpgsqlConnection CreateConnection()

=> NpgsqlConnection.FromDataSource(this);

/// <inheritdoc cref="DbDataSource.OpenConnection" />

public new NpgsqlConnection OpenConnection()

}

/// <inheritdoc />

protected override DbConnection OpenDbConnection()

=> OpenConnection();

/// <inheritdoc cref="DbDataSource.OpenConnectionAsync" />

public new async ValueTask<NpgsqlConnection> OpenConnectionAsync(CancellationToken cancellationToken = default)

}

/// <inheritdoc />

protected override async ValueTask<DbConnection> OpenDbConnectionAsync(CancellationToken cancellationToken = default)

=> await OpenConnectionAsync(cancellationToken).ConfigureAwait(false);

/// <inheritdoc />

protected override DbConnection CreateDbConnection()

=> CreateConnection();

/// <inheritdoc />

protected override DbCommand CreateDbCommand(string? commandText = null)

=> CreateCommand(commandText);

/// <inheritdoc />

protected override DbBatch CreateDbBatch()

=> CreateBatch();

/// <summary>

/// Creates a command ready for use against this <see cref="NpgsqlDataSource" />.

/// </summary>

/// <param name="commandText">An optional SQL for the command.</param>

public new NpgsqlCommand CreateCommand(string? commandText = null)

=> new NpgsqlDataSourceCommand(CreateConnection()) { CommandText = commandText };

/// <summary>

/// Creates a batch ready for use against this <see cref="NpgsqlDataSource" />.

/// </summary>

public new NpgsqlBatch CreateBatch()

=> new NpgsqlDataSourceBatch(CreateConnection());

/// <summary>

/// Creates a new <see cref="NpgsqlDataSource" /> for the given <paramref name="connectionString" />.

/// </summary>

public static NpgsqlDataSource Create(string connectionString)

=> new NpgsqlDataSourceBuilder(connectionString).Build();

/// <summary>

/// Creates a new <see cref="NpgsqlDataSource" /> for the given <paramref name="connectionStringBuilder" />.

/// </summary>

public static NpgsqlDataSource Create(NpgsqlConnectionStringBuilder connectionStringBuilder)

=> Create(connectionStringBuilder.ToString());

internal async Task Bootstrap(

}

#region Password management

/// <summary>

/// Manually sets the password to be used the next time a physical connection is opened.

/// Consider using <see cref="NpgsqlDataSourceBuilder.UsePeriodicPasswordProvider" /> instead.

/// </summary>

public string Password

}

internal ValueTask<string?> GetPassword(bool async, CancellationToken cancellationToken = default)

{

if (_passwordProvider is not null)

return GetPassword(async, cancellationToken);

// A periodic password provider is configured, but the first refresh hasn't completed yet (race condition).

if (_password is null && _periodicPasswordProvider is not null)

return GetInitialPeriodicPassword(async);

return new(_password);

async ValueTask<string?> GetInitialPeriodicPassword(bool async)

{

if (async)

await _passwordRefreshTask.ConfigureAwait(false);

else

_passwordRefreshTask.GetAwaiter().GetResult();

Debug.Assert(_password is not null);

return _password;

}

async ValueTask<string?> GetPassword(bool async, CancellationToken cancellationToken)

{

try

{

return async ? await _passwordProviderAsync!(Settings, cancellationToken).ConfigureAwait(false) : _passwordProvider(Settings);

}

catch (Exception e)

{

_connectionLogger.LogError(e, "Password provider threw an exception");

throw new NpgsqlException("An exception was thrown from the password provider", e);

}

}

}

async Task RefreshPassword()

{

try

{

_password = await _periodicPasswordProvider!(Settings, _timerPasswordProviderCancellationTokenSource!.Token).ConfigureAwait(false);

_periodicPasswordProviderTimer!.Change(_periodicPasswordSuccessRefreshInterval, Timeout.InfiniteTimeSpan);

}

catch (Exception e)

{

_connectionLogger.LogError(e, "Periodic password provider threw an exception");

_periodicPasswordProviderTimer!.Change(_periodicPasswordFailureRefreshInterval, Timeout.InfiniteTimeSpan);

throw new NpgsqlException("An exception was thrown from the periodic password provider", e);

}

}

#endregion Password management

internal abstract ValueTask<NpgsqlConnector> Get(

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

internal abstract bool TryGetIdleConnector([NotNullWhen(true)] out NpgsqlConnector? connector);

internal abstract ValueTask<NpgsqlConnector?> OpenNewConnector(

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

internal abstract void Return(NpgsqlConnector connector);

internal abstract void Clear();

internal abstract bool OwnsConnectors { get; }

#region Database state management

internal DatabaseState GetDatabaseState(bool ignoreExpiration = false)

{

Debug.Assert(this is not NpgsqlMultiHostDataSource);

var databaseStateInfo = _databaseStateInfo;

return ignoreExpiration || !databaseStateInfo.Timeout.HasExpired

? databaseStateInfo.State

: DatabaseState.Unknown;

}

internal DatabaseState UpdateDatabaseState(

DatabaseState newState,

DateTime timeStamp,

TimeSpan stateExpiration,

bool ignoreTimeStamp = false)

{

Debug.Assert(this is not NpgsqlMultiHostDataSource);

var databaseStateInfo = _databaseStateInfo;

if (!ignoreTimeStamp && timeStamp <= databaseStateInfo.TimeStamp)

return _databaseStateInfo.State;

_databaseStateInfo = new(newState, new NpgsqlTimeout(stateExpiration), timeStamp);

return newState;

}

#endregion Database state management

#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>(1);

list.Add(connector);

}

}

internal virtual bool TryRemovePendingEnlistedConnector(NpgsqlConnector connector, Transaction transaction)

{

lock (_pendingEnlistedConnectors)

{

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

return false;

list.Remove(connector);

if (list.Count == 0)

_pendingEnlistedConnectors.Remove(transaction);

return true;

}

}

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

#region Dispose

/// <inheritdoc />

protected sealed override void Dispose(bool disposing)

{

if (disposing && Interlocked.CompareExchange(ref _isDisposed, 1, 0) == 0)

DisposeBase();

}

/// <inheritdoc cref="Dispose" />

protected virtual void DisposeBase()

{

var cancellationTokenSource = _timerPasswordProviderCancellationTokenSource;

if (cancellationTokenSource is not null)

{

cancellationTokenSource.Cancel();

cancellationTokenSource.Dispose();

}

_periodicPasswordProviderTimer?.Dispose();

_setupMappingsSemaphore.Dispose();

MetricsReporter.Dispose();

Clear();

}

/// <inheritdoc />

protected sealed override ValueTask DisposeAsyncCore()

{

if (Interlocked.CompareExchange(ref _isDisposed, 1, 0) == 0)

return DisposeAsyncBase();

return default;

}

/// <inheritdoc cref="DisposeAsyncCore" />

protected virtual async ValueTask DisposeAsyncBase()

{

var cancellationTokenSource = _timerPasswordProviderCancellationTokenSource;

if (cancellationTokenSource is not null)

{

cancellationTokenSource.Cancel();

cancellationTokenSource.Dispose();

}

if (_periodicPasswordProviderTimer is not null)

await _periodicPasswordProviderTimer.DisposeAsync().ConfigureAwait(false);

_setupMappingsSemaphore.Dispose();

MetricsReporter.Dispose();

// TODO: async Clear, #4499

Clear();

}

private protected void CheckDisposed()

{

if (_isDisposed == 1)

ThrowHelper.ThrowObjectDisposedException(GetType().FullName);

}

#endregion

sealed class DatabaseStateInfo

{

internal readonly DatabaseState State;

internal readonly NpgsqlTimeout Timeout;

// While the TimeStamp is not strictly required, it does lower the risk of overwriting the current state with an old value

internal readonly DateTime TimeStamp;

public DatabaseStateInfo() : this(default, default, default) { }

public DatabaseStateInfo(DatabaseState state, NpgsqlTimeout timeout, DateTime timeStamp)

=> (State, Timeout, TimeStamp) = (state, timeout, timeStamp);

}