using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Data.Common;

using System.Diagnostics;

using System.Linq;

using System.Runtime.CompilerServices;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

using System.Globalization;

using JetBrains.Annotations;

using Npgsql.BackendMessages;

using Npgsql.FrontendMessages;

using Npgsql.Logging;

using NpgsqlTypes;

using static Npgsql.Statics;

namespace Npgsql

/// <summary>

/// Represents a SQL statement or function (stored procedure) to execute

/// against a PostgreSQL database. This class cannot be inherited.

/// </summary>

// ReSharper disable once RedundantNameQualifier

[System.ComponentModel.DesignerCategory("")]

public sealed class NpgsqlCommand : DbCommand, ICloneable

{

#region Fields

[CanBeNull]

NpgsqlConnection _connection;

/// <summary>

/// If this command is (explicitly) prepared, references the connector on which the preparation happened.

/// Used to detect when the connector was changed (i.e. connection open/close), meaning that the command

/// is no longer prepared.

/// </summary>

[CanBeNull]

NpgsqlConnector _connectorPreparedOn;

NpgsqlTransaction _transaction;

string _commandText;

int? _timeout;

readonly NpgsqlParameterCollection _parameters;

readonly List<NpgsqlStatement> _statements;

/// <summary>

/// Returns details about each statement that this command has executed.

/// Is only populated when an Execute* method is called.

/// </summary>

public IReadOnlyList<NpgsqlStatement> Statements => _statements.AsReadOnly();

UpdateRowSource _updateRowSource = UpdateRowSource.Both;

bool IsExplicitlyPrepared => _connectorPreparedOn != null;

static readonly SingleThreadSynchronizationContext SingleThreadSynchronizationContext = new SingleThreadSynchronizationContext("NpgsqlRemainingAsyncSendWorker");

static readonly NpgsqlLogger Log = NpgsqlLogManager.GetCurrentClassLogger();

#endregion Fields

#region Constants

internal const int DefaultTimeout = 30;

#endregion

#region Constructors

/// <summary>

/// Initializes a new instance of the <see cref="NpgsqlCommand">NpgsqlCommand</see> class.

/// </summary>

public NpgsqlCommand() : this(string.Empty, null, null) {}

/// <summary>

/// Initializes a new instance of the <see cref="NpgsqlCommand">NpgsqlCommand</see> class with the text of the query.

/// </summary>

/// <param name="cmdText">The text of the query.</param>

// ReSharper disable once IntroduceOptionalParameters.Global

public NpgsqlCommand(string cmdText) : this(cmdText, null, null) {}

/// <summary>

/// Initializes a new instance of the <see cref="NpgsqlCommand">NpgsqlCommand</see> class with the text of the query and a <see cref="NpgsqlConnection">NpgsqlConnection</see>.

/// </summary>

/// <param name="cmdText">The text of the query.</param>

/// <param name="connection">A <see cref="NpgsqlConnection">NpgsqlConnection</see> that represents the connection to a PostgreSQL server.</param>

// ReSharper disable once IntroduceOptionalParameters.Global

public NpgsqlCommand(string cmdText, NpgsqlConnection connection) : this(cmdText, connection, null) {}

/// <summary>

/// Initializes a new instance of the <see cref="NpgsqlCommand">NpgsqlCommand</see> class with the text of the query, a <see cref="NpgsqlConnection">NpgsqlConnection</see>, and the <see cref="NpgsqlTransaction">NpgsqlTransaction</see>.

/// </summary>

/// <param name="cmdText">The text of the query.</param>

/// <param name="connection">A <see cref="NpgsqlConnection">NpgsqlConnection</see> that represents the connection to a PostgreSQL server.</param>

/// <param name="transaction">The <see cref="NpgsqlTransaction">NpgsqlTransaction</see> in which the <see cref="NpgsqlCommand">NpgsqlCommand</see> executes.</param>

public NpgsqlCommand(string cmdText, [CanBeNull] NpgsqlConnection connection, [CanBeNull] NpgsqlTransaction transaction)

}

#endregion Constructors

#region Public properties

/// <summary>

/// Gets or sets the SQL statement or function (stored procedure) to execute at the data source.

/// </summary>

/// <value>The Transact-SQL statement or stored procedure to execute. The default is an empty string.</value>

[DefaultValue("")]

[Category("Data")]

public override string CommandText

}

/// <summary>

/// Gets or sets the wait time before terminating the attempt to execute a command and generating an error.

/// </summary>

/// <value>The time (in seconds) to wait for the command to execute. The default value is 30 seconds.</value>

[DefaultValue(DefaultTimeout)]

public override int CommandTimeout

}

/// <summary>

/// Gets or sets a value indicating how the

/// <see cref="NpgsqlCommand.CommandText">CommandText</see> property is to be interpreted.

/// </summary>

/// <value>One of the <see cref="System.Data.CommandType">CommandType</see> values. The default is <see cref="System.Data.CommandType">CommandType.Text</see>.</value>

[DefaultValue(CommandType.Text)]

[Category("Data")]

public override CommandType CommandType { get; set; }

/// <summary>

/// DB connection.

/// </summary>

protected override DbConnection DbConnection

}

/// <summary>

/// Gets or sets the <see cref="NpgsqlConnection">NpgsqlConnection</see>

/// used by this instance of the <see cref="NpgsqlCommand">NpgsqlCommand</see>.

/// </summary>

/// <value>The connection to a data source. The default value is a null reference.</value>

[DefaultValue(null)]

[Category("Behavior")]

[CanBeNull]

public new NpgsqlConnection Connection

}

/// <summary>

/// Design time visible.

/// </summary>

public override bool DesignTimeVisible { get; set; }

/// <summary>

/// Gets or sets how command results are applied to the DataRow when used by the

/// DbDataAdapter.Update(DataSet) method.

/// </summary>

/// <value>One of the <see cref="System.Data.UpdateRowSource">UpdateRowSource</see> values.</value>

[Category("Behavior"), DefaultValue(UpdateRowSource.Both)]

public override UpdateRowSource UpdatedRowSource

}

/// <summary>

/// Returns whether this query will execute as a prepared (compiled) query.

/// </summary>

public bool IsPrepared =>

_connectorPreparedOn == Connection?.Connector &&

_statements.Any() && _statements.All(s => s.PreparedStatement?.IsPrepared == true);

#endregion Public properties

#region Known/unknown Result Types Management

/// <summary>

/// Marks all of the query's result columns as either known or unknown.

/// Unknown results column are requested them from PostgreSQL in text format, and Npgsql makes no

/// attempt to parse them. They will be accessible as strings only.

/// </summary>

public bool AllResultTypesAreUnknown

}

bool _allResultTypesAreUnknown;

/// <summary>

/// Marks the query's result columns as known or unknown, on a column-by-column basis.

/// Unknown results column are requested them from PostgreSQL in text format, and Npgsql makes no

/// attempt to parse them. They will be accessible as strings only.

/// </summary>

/// <remarks>

/// If the query includes several queries (e.g. SELECT 1; SELECT 2), this will only apply to the first

/// one. The rest of the queries will be fetched and parsed as usual.

///

/// The array size must correspond exactly to the number of result columns the query returns, or an

/// error will be raised.

/// </remarks>

public bool[] UnknownResultTypeList

}

bool[] _unknownResultTypeList;

#endregion

#region Result Types Management

/// <summary>

/// Marks result types to be used when using GetValue on a data reader, on a column-by-column basis.

/// Used for Entity Framework 5-6 compability.

/// Only primitive numerical types and DateTimeOffset are supported.

/// Set the whole array or just a value to null to use default type.

/// </summary>

internal Type[] ObjectResultTypes { get; set; }

#endregion

#region State management

int _state;

/// <summary>

/// Gets the current state of the connector

/// </summary>

internal CommandState State

}

void ResetExplicitPreparation() => _connectorPreparedOn = null;

#endregion State management

#region Parameters

/// <summary>

/// Creates a new instance of an <see cref="System.Data.Common.DbParameter">DbParameter</see> object.

/// </summary>

/// <returns>An <see cref="System.Data.Common.DbParameter">DbParameter</see> object.</returns>

protected override DbParameter CreateDbParameter()

{

return CreateParameter();

}

/// <summary>

/// Creates a new instance of a <see cref="NpgsqlParameter">NpgsqlParameter</see> object.

/// </summary>

/// <returns>A <see cref="NpgsqlParameter">NpgsqlParameter</see> object.</returns>

public new NpgsqlParameter CreateParameter()

{

return new NpgsqlParameter();

}

/// <summary>

/// DB parameter collection.

/// </summary>

protected override DbParameterCollection DbParameterCollection => Parameters;

/// <summary>

/// Gets the <see cref="NpgsqlParameterCollection">NpgsqlParameterCollection</see>.

/// </summary>

/// <value>The parameters of the SQL statement or function (stored procedure). The default is an empty collection.</value>

public new NpgsqlParameterCollection Parameters => _parameters;

#endregion

#region DeriveParameters

const string DeriveParametersForFunctionQuery = @"

internal void DeriveParameters()

}

void DeriveParametersForFunction()

}

void DeriveParametersForQuery()

}

#endregion

#region Prepare

/// <summary>

/// Creates a server-side prepared statement on the PostgreSQL server.

/// This will make repeated future executions of this command much faster.

/// </summary>

public override void Prepare() => Prepare(false).GetAwaiter().GetResult();

/// <summary>

/// Creates a server-side prepared statement on the PostgreSQL server.

/// This will make repeated future executions of this command much faster.

/// </summary>

public Task PrepareAsync() => PrepareAsync(CancellationToken.None);

/// <summary>

/// Creates a server-side prepared statement on the PostgreSQL server.

/// This will make repeated future executions of this command much faster.

/// </summary>

#pragma warning disable CA1801 // Review unused parameters

public Task PrepareAsync(CancellationToken cancellationToken)

}

Task Prepare(bool async)

{

var connector = CheckReadyAndGetConnector();

for (var i = 0; i < Parameters.Count; i++)

Parameters[i].Bind(connector.TypeMapper);

ProcessRawQuery();

Log.Debug($"Preparing: {CommandText}", connector.Id);

var needToPrepare = false;

foreach (var statement in _statements)

{

if (statement.IsPrepared)

continue;

statement.PreparedStatement = connector.PreparedStatementManager.GetOrAddExplicit(statement);

if (statement.PreparedStatement?.State == PreparedState.NotPrepared)

{

statement.PreparedStatement.State = PreparedState.ToBePrepared;

needToPrepare = true;

}

}

_connectorPreparedOn = connector;

// It's possible the command was already prepared, or that persistent prepared statements were found for

// all statements. Nothing to do here, move along.

return needToPrepare

? PrepareLong()

: PGUtil.CompletedTask;

async Task PrepareLong()

{

using (connector.StartUserAction())

{

var sendTask = SendPrepare(async);

// Loop over statements, skipping those that are already prepared (because they were persisted)

var isFirst = true;

foreach (var statement in _statements.Where(s =>

s.PreparedStatement?.State == PreparedState.BeingPrepared))

{

var pStatement = statement.PreparedStatement;

Debug.Assert(pStatement != null);

Debug.Assert(pStatement.Description == null);

if (pStatement.StatementBeingReplaced != null)

{

Expect<CloseCompletedMessage>(await connector.ReadMessage(async));

pStatement.StatementBeingReplaced.CompleteUnprepare();

pStatement.StatementBeingReplaced = null;

}

Expect<ParseCompleteMessage>(await connector.ReadMessage(async));

Expect<ParameterDescriptionMessage>(await connector.ReadMessage(async));

var msg = await connector.ReadMessage(async);

switch (msg.Code)

{

case BackendMessageCode.RowDescription:

var description = (RowDescriptionMessage)msg;

FixupRowDescription(description, isFirst);

statement.Description = description;

break;

case BackendMessageCode.NoData:

statement.Description = null;

break;

default:

throw connector.UnexpectedMessageReceived(msg.Code);

}

pStatement.CompletePrepare();

isFirst = false;

}

Expect<ReadyForQueryMessage>(await connector.ReadMessage(async));

if (async)

await sendTask;

else

sendTask.GetAwaiter().GetResult();

}

}

}

/// <summary>

/// Unprepares a command, closing server-side statements associated with it.

/// Note that this only affects commands explicitly prepared with <see cref="Prepare()"/>, not

/// automatically prepared statements.

/// </summary>

public void Unprepare()

{

if (_statements.All(s => !s.IsPrepared))

return;

var connector = CheckReadyAndGetConnector();

Log.Debug("Closing command's prepared statements", connector.Id);

using (connector.StartUserAction())

{

var sendTask = SendClose(false);

foreach (var statement in _statements.Where(s => s.PreparedStatement?.State == PreparedState.BeingUnprepared))

{

Expect<CloseCompletedMessage>(connector.ReadMessage());

Debug.Assert(statement.PreparedStatement != null);

statement.PreparedStatement.CompleteUnprepare();

statement.PreparedStatement = null;

}

Expect<ReadyForQueryMessage>(connector.ReadMessage());

sendTask.GetAwaiter().GetResult();

}

}

#endregion Prepare

#region Query analysis

void ProcessRawQuery(bool deriveParameters = false)

{

NpgsqlStatement statement;

switch (CommandType) {

case CommandType.Text:

Debug.Assert(_connection?.Connector != null);

var connector = _connection.Connector;

connector.SqlParser.ParseRawQuery(CommandText, connector.UseConformantStrings, _parameters, _statements, deriveParameters);

if (_statements.Count > 1 && _parameters.HasOutputParameters)

throw new NotSupportedException("Commands with multiple queries cannot have out parameters");

break;

case CommandType.TableDirect:

if (_statements.Count == 0)

statement = new NpgsqlStatement();

else

{

statement = _statements[0];

statement.Reset();

_statements.Clear();

}

_statements.Add(statement);

statement.SQL = "SELECT * FROM " + CommandText;

break;

case CommandType.StoredProcedure:

var inputList = _parameters.Where(p => p.IsInputDirection).ToList();

var numInput = inputList.Count;

var sb = new StringBuilder();

sb.Append("SELECT * FROM ");

sb.Append(CommandText);

sb.Append('(');

var hasWrittenFirst = false;

for (var i = 1; i <= numInput; i++) {

var param = inputList[i - 1];

if (param.TrimmedName == "")

{

if (hasWrittenFirst)

sb.Append(',');

sb.Append('$');

sb.Append(i);

hasWrittenFirst = true;

}

}

for (var i = 1; i <= numInput; i++)

{

var param = inputList[i - 1];

if (param.TrimmedName != "")

{

if (hasWrittenFirst)

sb.Append(',');

sb.Append('"');

sb.Append(param.TrimmedName.Replace("\"", "\"\""));

sb.Append("\" := ");

sb.Append('$');

sb.Append(i);

hasWrittenFirst = true;

}

}

sb.Append(')');

if (_statements.Count == 0)

statement = new NpgsqlStatement();

else

{

statement = _statements[0];

statement.Reset();

_statements.Clear();

}

statement.SQL = sb.ToString();

statement.InputParameters.AddRange(inputList);

_statements.Add(statement);

break;

default:

throw new InvalidOperationException($"Internal Npgsql bug: unexpected value {CommandType} of enum {nameof(CommandType)}. Please file a bug.");

}

foreach (var s in _statements)

if (s.InputParameters.Count > 65535)

throw new Exception("A statement cannot have more than 65535 parameters");

}

#endregion

#region Execute

void ValidateParameters()

{

for (var i = 0; i < Parameters.Count; i++)

{

var p = Parameters[i];

if (!p.IsInputDirection)

continue;

p.Bind(Connection.Connector.TypeMapper);

p.LengthCache?.Clear();

p.ValidateAndGetLength();

}

}

#endregion

#region Message Creation / Population

internal bool FlushOccurred { get; set; }

void BeginSend()

{

Debug.Assert(Connection?.Connector != null);

Connection.Connector.WriteBuffer.CurrentCommand = this;

FlushOccurred = false;

}

void CleanupSend()

{

// ReSharper disable once ConditionIsAlwaysTrueOrFalse

if (SynchronizationContext.Current != null) // Check first because SetSynchronizationContext allocates

SynchronizationContext.SetSynchronizationContext(null);

}

async Task SendExecute(bool async)

{

BeginSend();

var connector = Connection.Connector;

Debug.Assert(connector != null);

var buf = connector.WriteBuffer;

for (var i = 0; i < _statements.Count; i++)

{

async = ForceAsyncIfNecessary(async, i);

var statement = _statements[i];

var pStatement = statement.PreparedStatement;

if (pStatement == null || pStatement.State == PreparedState.ToBePrepared)

{

if (pStatement?.StatementBeingReplaced != null)

{

// We have a prepared statement that replaces an existing statement - close the latter first.

await connector.CloseMessage

.Populate(StatementOrPortal.Statement, pStatement.StatementBeingReplaced.Name)

.Write(buf, async);

}

await connector.ParseMessage

.Populate(statement.SQL, statement.StatementName, statement.InputParameters, connector.TypeMapper)

.Write(buf, async);

}

var bind = connector.BindMessage;

bind.Populate(statement.InputParameters, "", statement.StatementName);

if (AllResultTypesAreUnknown)

bind.AllResultTypesAreUnknown = AllResultTypesAreUnknown;

else if (i == 0 && UnknownResultTypeList != null)

bind.UnknownResultTypeList = UnknownResultTypeList;

await connector.BindMessage.Write(buf, async);

if (pStatement == null || pStatement.State == PreparedState.ToBePrepared)

{

await connector.DescribeMessage

.Populate(StatementOrPortal.Portal)

.Write(buf, async);

if (statement.PreparedStatement != null)

statement.PreparedStatement.State = PreparedState.BeingPrepared;

}

await ExecuteMessage.DefaultExecute.Write(buf, async);

}

await SyncMessage.Instance.Write(buf, async);

await buf.Flush(async);

CleanupSend();

}

async Task SendExecuteSchemaOnly(bool async)

{

BeginSend();

var connector = Connection.Connector;

Debug.Assert(connector != null);

var wroteSomething = false;

var buf = connector.WriteBuffer;

for (var i = 0; i < _statements.Count; i++)

{

async = ForceAsyncIfNecessary(async, i);

var statement = _statements[i];

if (statement.PreparedStatement?.State == PreparedState.Prepared)

continue; // Prepared, we already have the RowDescription

Debug.Assert(statement.PreparedStatement == null);

await connector.ParseMessage

.Populate(statement.SQL, "", statement.InputParameters, connector.TypeMapper)

.Write(buf, async);

await connector.DescribeMessage

.Populate(StatementOrPortal.Statement, statement.StatementName)

.Write(buf, async);

wroteSomething = true;

}

if (wroteSomething)

{

await SyncMessage.Instance.Write(buf, async);

await buf.Flush(async);

}

CleanupSend();

}

async Task SendDeriveParameters(bool async)

{

BeginSend();

var connector = Connection.Connector;

Debug.Assert(connector != null);

var buf = connector.WriteBuffer;

for (var i = 0; i < _statements.Count; i++)

{

async = ForceAsyncIfNecessary(async, i);

await connector.ParseMessage

.Populate(_statements[i].SQL, string.Empty)

.Write(buf, async);

await connector.DescribeMessage

.Populate(StatementOrPortal.Statement, string.Empty)

.Write(buf, async);

}

await SyncMessage.Instance.Write(buf, async);

await buf.Flush(async);

CleanupSend();

}

async Task SendPrepare(bool async)

{

BeginSend();

var connector = Connection.Connector;

Debug.Assert(connector != null);

var buf = connector.WriteBuffer;

for (var i = 0; i < _statements.Count; i++)

{

async = ForceAsyncIfNecessary(async, i);

var statement = _statements[i];

var pStatement = statement.PreparedStatement;

// A statement may be already prepared, already in preparation (i.e. same statement twice

// in the same command), or we can't prepare (overloaded SQL)

if (pStatement?.State != PreparedState.ToBePrepared)

continue;

var statementToClose = pStatement?.StatementBeingReplaced;

if (statementToClose != null)

{

// We have a prepared statement that replaces an existing statement - close the latter first.

await connector.CloseMessage

.Populate(StatementOrPortal.Statement, statementToClose.Name)

.Write(buf, async);

}

await connector.ParseMessage

.Populate(statement.SQL, pStatement.Name, statement.InputParameters, connector.TypeMapper)

.Write(buf, async);

await connector.DescribeMessage

.Populate(StatementOrPortal.Statement, pStatement.Name)

.Write(buf, async);

pStatement.State = PreparedState.BeingPrepared;

}

await SyncMessage.Instance.Write(buf, async);

await buf.Flush(async);

CleanupSend();

}

bool ForceAsyncIfNecessary(bool async, int numberOfStatementInBatch)

{

if (!async && FlushOccurred && numberOfStatementInBatch > 0)

{

// We're synchronously sending the non-first statement in a batch and a flush

// has already occured. Switch to async. See long comment in Execute() above.

async = true;

SynchronizationContext.SetSynchronizationContext(SingleThreadSynchronizationContext);

}

return async;

}

async Task SendClose(bool async)

{

BeginSend();

var connector = Connection.Connector;

Debug.Assert(connector != null);

var buf = connector.WriteBuffer;

foreach (var statement in _statements.Where(s => s.IsPrepared))

{

if (FlushOccurred)

{

async = true;

SynchronizationContext.SetSynchronizationContext(SingleThreadSynchronizationContext);

}

await connector.CloseMessage

.Populate(StatementOrPortal.Statement, statement.StatementName)

.Write(buf, async);

Debug.Assert(statement.PreparedStatement != null);

statement.PreparedStatement.State = PreparedState.BeingUnprepared;

}

await SyncMessage.Instance.Write(buf, async);

await buf.Flush(async);

CleanupSend();

}

#endregion

#region Execute Non Query

/// <summary>

/// Executes a SQL statement against the connection and returns the number of rows affected.

/// </summary>

/// <returns>The number of rows affected if known; -1 otherwise.</returns>