Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / SqlClient / SqlInternalConnection.cs / 10 / SqlInternalConnection.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// [....]
// [....]
//-----------------------------------------------------------------------------
namespace System.Data.SqlClient
{
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Data.ProviderBase;
using System.Diagnostics;
using System.Globalization;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using System.Text;
using System.Threading;
using SysTx = System.Transactions;
abstract internal class SqlInternalConnection : DbConnectionInternal {
private readonly SqlConnectionString _connectionOptions;
private string _currentDatabase;
private string _currentDataSource;
private bool _isEnlistedInTransaction; // is the server-side connection enlisted? true while we're enlisted, reset only after we send a null...
private byte[] _promotedDTCToken; // token returned by the server when we promote transaction
private SqlDelegatedTransaction _delegatedTransaction; // the delegated (or promoted) transaction we're responsible for.
private byte[] _whereAbouts; // cache the whereabouts (DTC Address) for exporting
internal enum TransactionRequest {
Begin,
Promote,
Commit,
Rollback,
IfRollback,
Save
};
internal SqlInternalConnection(SqlConnectionString connectionOptions) : base() {
Debug.Assert(null != connectionOptions, "null connectionOptions?");
_connectionOptions = connectionOptions;
}
internal SqlConnection Connection {
get {
return (SqlConnection)Owner;
}
}
internal SqlConnectionString ConnectionOptions {
get {
return _connectionOptions;
}
}
internal string CurrentDatabase {
get {
return _currentDatabase;
}
set {
_currentDatabase = value;
}
}
internal string CurrentDataSource {
get {
return _currentDataSource;
}
set {
_currentDataSource = value;
}
}
internal SqlDelegatedTransaction DelegatedTransaction {
get {
return _delegatedTransaction;
}
set {
_delegatedTransaction = value;
}
}
abstract internal SqlInternalTransaction CurrentTransaction {
get;
}
//
virtual internal SqlInternalTransaction AvailableInternalTransaction {
get {
return CurrentTransaction;
}
}
abstract internal SqlInternalTransaction PendingTransaction {
get;
}
override internal bool RequireExplicitTransactionUnbind {
get {
return _connectionOptions.TransactionBinding == SqlConnectionString.TransactionBindingEnum.ExplicitUnbind;
}
}
override protected internal bool IsNonPoolableTransactionRoot {
get {
return IsTransactionRoot; // default behavior is that root transactions are NOT poolable. Subclasses may override.
}
}
override internal bool IsTransactionRoot {
get {
if (null == _delegatedTransaction) {
return false;
}
lock (this) {
return (null != _delegatedTransaction && _delegatedTransaction.IsActive);
}
}
}
internal bool HasLocalTransaction {
get {
SqlInternalTransaction currentTransaction = CurrentTransaction;
bool result = (null != currentTransaction && currentTransaction.IsLocal);
return result;
}
}
internal bool HasLocalTransactionFromAPI {
get {
SqlInternalTransaction currentTransaction = CurrentTransaction;
bool result = (null != currentTransaction && currentTransaction.HasParentTransaction);
return result;
}
}
internal bool IsEnlistedInTransaction {
get {
return _isEnlistedInTransaction;
}
}
// Workaround to access context transaction without rewriting connection pool & internalconnections properly.
// Context transactions SHOULD be considered enlisted.
// This works for now only because we can't unenlist from the context transaction
// DON'T START USING THIS ANYWHERE EXCEPT IN InternalTransaction and in InternalConnectionSmi!!!
private SysTx.Transaction _contextTransaction;
protected internal SysTx.Transaction ContextTransaction {
get {
return _contextTransaction;
}
set {
_contextTransaction = value;
}
}
internal SysTx.Transaction InternalEnlistedTransaction {
get {
// Workaround to access context transaction without rewriting connection pool & internalconnections properly.
// This SHOULD be a simple wrapper around EnlistedTransaction.
// This works for now only because we can't unenlist from the context transaction
SysTx.Transaction tx = EnlistedTransaction;
if (null == tx) {
tx = ContextTransaction;
}
return tx;
}
}
abstract internal bool IsLockedForBulkCopy {
get;
}
abstract internal bool IsShiloh {
get;
}
abstract internal bool IsYukonOrNewer {
get;
}
abstract internal bool IsKatmaiOrNewer {
get;
}
#if WINFSFunctionality
abstract internal bool IsWinFS {
get;
}
#endif
internal byte[] PromotedDTCToken {
get {
return _promotedDTCToken;
}
set {
_promotedDTCToken = value;
}
}
abstract internal void AddPreparedCommand(SqlCommand cmd);
override public DbTransaction BeginTransaction(IsolationLevel iso) {
return BeginSqlTransaction(iso, null);
}
virtual internal SqlTransaction BeginSqlTransaction(IsolationLevel iso, string transactionName) {
SqlStatistics statistics = null;
RuntimeHelpers.PrepareConstrainedRegions();
try {
#if DEBUG
object initialReliabilitySlotValue = Thread.GetData(TdsParser.ReliabilitySlot);
RuntimeHelpers.PrepareConstrainedRegions();
try {
Thread.SetData(TdsParser.ReliabilitySlot, true);
#endif //DEBUG
statistics = SqlStatistics.StartTimer(Connection.Statistics);
SqlConnection.ExecutePermission.Demand(); // MDAC 81476
ValidateConnectionForExecute(null);
if (HasLocalTransactionFromAPI)
throw ADP.ParallelTransactionsNotSupported(Connection);
if (iso == IsolationLevel.Unspecified) {
iso = IsolationLevel.ReadCommitted; // Default to ReadCommitted if unspecified.
}
SqlTransaction transaction = new SqlTransaction(this, Connection, iso, AvailableInternalTransaction);
ExecuteTransaction(TransactionRequest.Begin, transactionName, iso, transaction.InternalTransaction, false);
return transaction;
#if DEBUG
}
finally {
Thread.SetData(TdsParser.ReliabilitySlot, initialReliabilitySlotValue);
}
#endif //DEBUG
}
catch (System.OutOfMemoryException e) {
Connection.Abort(e);
throw;
}
catch (System.StackOverflowException e) {
Connection.Abort(e);
throw;
}
catch (System.Threading.ThreadAbortException e) {
Connection.Abort(e);
throw;
}
finally {
SqlStatistics.StopTimer(statistics);
}
}
override public void ChangeDatabase(string database) {
SqlConnection.ExecutePermission.Demand(); // MDAC 80961
if (ADP.IsEmpty(database)) {
throw ADP.EmptyDatabaseName();
}
ValidateConnectionForExecute(null); //
ChangeDatabaseInternal(database); // do the real work...
}
abstract protected void ChangeDatabaseInternal(string database);
abstract internal void ClearPreparedCommands();
//
internal override void CloseConnection(DbConnection owningObject, DbConnectionFactory connectionFactory) {
if (!IsConnectionDoomed) {
ClearPreparedCommands();
}
base.CloseConnection(owningObject, connectionFactory);
}
override protected void CleanupTransactionOnCompletion(SysTx.Transaction transaction) {
// Note: unlocked, potentially multi-threaded code, so pull delegate to local to
// ensure it doesn't change between test and call.
SqlDelegatedTransaction delegatedTransaction = DelegatedTransaction;
if (null != delegatedTransaction) {
delegatedTransaction.TransactionEnded(transaction);
}
}
override protected DbReferenceCollection CreateReferenceCollection() {
return new SqlReferenceCollection();
}
override protected void Deactivate() {
if (Bid.AdvancedOn) {
Bid.Trace(" %d# deactivating\n", base.ObjectID);
}
RuntimeHelpers.PrepareConstrainedRegions();
try {
#if DEBUG
object initialReliabilitySlotValue = Thread.GetData(TdsParser.ReliabilitySlot);
RuntimeHelpers.PrepareConstrainedRegions();
try {
Thread.SetData(TdsParser.ReliabilitySlot, true);
#endif //DEBUG
SqlReferenceCollection referenceCollection = (SqlReferenceCollection)ReferenceCollection;
if (null != referenceCollection) {
referenceCollection.Deactivate();
}
// Invoke subclass-specific deactivation logic
InternalDeactivate();
#if DEBUG
}
finally {
Thread.SetData(TdsParser.ReliabilitySlot, initialReliabilitySlotValue);
}
#endif //DEBUG
}
catch (System.OutOfMemoryException) {
DoomThisConnection();
throw;
}
catch (System.StackOverflowException) {
DoomThisConnection();
throw;
}
catch (System.Threading.ThreadAbortException) {
DoomThisConnection();
throw;
}
catch (Exception e) {
//
if (!ADP.IsCatchableExceptionType(e)) {
throw;
}
// if an exception occurred, the inner connection will be
// marked as unusable and destroyed upon returning to the
// pool
DoomThisConnection();
ADP.TraceExceptionWithoutRethrow(e);
}
}
abstract internal void DisconnectTransaction(SqlInternalTransaction internalTransaction);
override public void Dispose() {
_whereAbouts = null;
base.Dispose();
}
protected void Enlist(SysTx.Transaction tx) {
// We should never be calling this method once we've created a
// delegated transaction, because the Manual enlistment should
// have caught this and thrown an exception, and the Auto enlistment
// isn't possible because Sys.Tx keeps the connection alive until
// the transaction is completed.
Debug.Assert (!IsNonPoolableTransactionRoot, "cannot defect a delegated transaction!"); // potential race condition, but it's an assert
if (null == tx) {
if (IsEnlistedInTransaction) {
EnlistNull();
}
}
// Only enlist if it's different...
else if (!tx.Equals(EnlistedTransaction)) { // WebData 20000024 - Must use Equals, not !=
EnlistNonNull(tx);
}
}
private void EnlistNonNull(SysTx.Transaction tx) {
Debug.Assert(null != tx, "null transaction?");
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, transaction %d#.\n", base.ObjectID, tx.GetHashCode());
}
bool hasDelegatedTransaction = false;
if (IsYukonOrNewer) {
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, attempting to delegate\n", base.ObjectID);
}
// Promotable transactions are only supported on Yukon
// servers or newer.
SqlDelegatedTransaction delegatedTransaction = new SqlDelegatedTransaction(this, tx);
try {
// NOTE: System.Transactions claims to resolve all
// potential race conditions between multiple delegate
// requests of the same transaction to different
// connections in their code, such that only one
// attempt to delegate will succeed.
// NOTE: PromotableSinglePhaseEnlist will eventually
// make a round trip to the server; doing this inside
// a lock is not the best choice. We presume that you
// aren't trying to enlist concurrently on two threads
// and leave it at that -- We don't claim any thread
// safety with regard to multiple concurrent requests
// to enlist the same connection in different
// transactions, which is good, because we don't have
// it anyway.
// PromotableSinglePhaseEnlist may not actually promote
// the transaction when it is already delegated (this is
// the way they resolve the race condition when two
// threads attempt to delegate the same Lightweight
// Transaction) In that case, we can safely ignore
// our delegated transaction, and proceed to enlist
// in the promoted one.
if (tx.EnlistPromotableSinglePhase(delegatedTransaction)) {
hasDelegatedTransaction = true;
_delegatedTransaction = delegatedTransaction;
if (Bid.AdvancedOn) {
long transactionId = SqlInternalTransaction.NullTransactionId;
int transactionObjectID = 0;
if (null != CurrentTransaction) {
transactionId = CurrentTransaction.TransactionId;
transactionObjectID = CurrentTransaction.ObjectID;
}
Bid.Trace(" %d#, delegated to transaction %d# with transactionId=0x%I64x\n", base.ObjectID, transactionObjectID, transactionId);
}
}
}
catch (SqlException e) {
// we do not want to eat the error if it is a fatal one
if (e.Class >= TdsEnums.FATAL_ERROR_CLASS) {
throw;
}
// if the parser is not openloggedin, the connection is no longer good
SqlInternalConnectionTds tdsConnection = this as SqlInternalConnectionTds;
if (tdsConnection != null) {
if (tdsConnection.Parser.State != TdsParserState.OpenLoggedIn) {
throw;
}
}
ADP.TraceExceptionWithoutRethrow(e);
// In this case, SqlDelegatedTransaction.Initialize
// failed and we don't necessarily want to reject
// things -- there may have been a legitimate reason
// for the failure.
}
}
if (!hasDelegatedTransaction) {
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, delegation not possible, enlisting.\n", base.ObjectID);
}
byte[] cookie = null;
if (null == _whereAbouts) {
byte[] dtcAddress = GetDTCAddress();
if (null == dtcAddress) {
throw SQL.CannotGetDTCAddress();
}
_whereAbouts = dtcAddress;
}
cookie = GetTransactionCookie(tx, _whereAbouts);
// send cookie to server to finish enlistment
PropagateTransactionCookie(cookie);
_isEnlistedInTransaction = true;
if (Bid.AdvancedOn) {
long transactionId = SqlInternalTransaction.NullTransactionId;
int transactionObjectID = 0;
if (null != CurrentTransaction) {
transactionId = CurrentTransaction.TransactionId;
transactionObjectID = CurrentTransaction.ObjectID;
}
Bid.Trace(" %d#, enlisted with transaction %d# with transactionId=0x%I64x\n", base.ObjectID, transactionObjectID, transactionId);
}
}
EnlistedTransaction = tx; // Tell the base class about our enlistment
// If we're on a Yukon or newer server, and we we delegate the
// transaction successfully, we will have done a begin transaction,
// which produces a transaction id that we should execute all requests
// on. The TdsParser or SmiEventSink will store this information as
// the current transaction.
//
// Likewise, propagating a transaction to a Yukon or newer server will
// produce a transaction id that The TdsParser or SmiEventSink will
// store as the current transaction.
//
// In either case, when we're working with a Yukon or newer server
// we better have a current transaction by now.
Debug.Assert(!IsYukonOrNewer || null != CurrentTransaction, "delegated/enlisted transaction with null current transaction?");
}
internal void EnlistNull() {
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, unenlisting.\n", base.ObjectID);
}
// We were in a transaction, but now we are not - so send
// message to server with empty transaction - confirmed proper
// behavior from Sameet Agarwal
//
// The connection pooler maintains separate pools for enlisted
// transactions, and only when that transaction is committed or
// rolled back will those connections be taken from that
// separate pool and returned to the general pool of connections
// that are not affiliated with any transactions. When this
// occurs, we will have a new transaction of null and we are
// required to send an empty transaction payload to the server.
PropagateTransactionCookie(null);
_isEnlistedInTransaction = false;
EnlistedTransaction = null; // Tell the base class about our enlistment
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, unenlisted.\n", base.ObjectID);
}
// The EnlistTransaction above will return an TransactionEnded event,
// which causes the TdsParser or SmiEventSink should to clear the
// current transaction.
//
// In either case, when we're working with a Yukon or newer server
// we better not have a current transaction at this point.
Debug.Assert(!IsYukonOrNewer || null == CurrentTransaction, "unenlisted transaction with non-null current transaction?"); // verify it!
}
override public void EnlistTransaction(SysTx.Transaction transaction) {
SqlConnection.VerifyExecutePermission();
ValidateConnectionForExecute(null);
// If a connection has a local transaction outstanding and you try
// to enlist in a DTC transaction, SQL Server will rollback the
// local transaction and then do the enlist (7.0 and 2000). So, if
// the user tries to do this, throw.
if (HasLocalTransaction) {
throw ADP.LocalTransactionPresent();
}
if (null != transaction && transaction.Equals(EnlistedTransaction)) {
// No-op if this is the current transaction
return;
}
// If a connection is already enlisted in a DTC transaction and you
// try to enlist in another one, in 7.0 the existing DTC transaction
// would roll back and then the connection would enlist in the new
// one. In SQL 2000 & Yukon, when you enlist in a DTC transaction
// while the connection is already enlisted in a DTC transaction,
// the connection simply switches enlistments. Regardless, simply
// enlist in the user specified distributed transaction. This
// behavior matches OLEDB and ODBC.
RuntimeHelpers.PrepareConstrainedRegions();
try {
#if DEBUG
object initialReliabilitySlotValue = Thread.GetData(TdsParser.ReliabilitySlot);
RuntimeHelpers.PrepareConstrainedRegions();
try {
Thread.SetData(TdsParser.ReliabilitySlot, true);
#endif //DEBUG
Enlist(transaction);
#if DEBUG
}
finally {
Thread.SetData(TdsParser.ReliabilitySlot, initialReliabilitySlotValue);
}
#endif //DEBUG
}
catch (System.OutOfMemoryException e) {
Connection.Abort(e);
throw;
}
catch (System.StackOverflowException e) {
Connection.Abort(e);
throw;
}
catch (System.Threading.ThreadAbortException e) {
Connection.Abort(e);
throw;
}
}
abstract internal void ExecuteTransaction(TransactionRequest transactionRequest, string name, IsolationLevel iso, SqlInternalTransaction internalTransaction, bool isDelegateControlRequest);
internal SqlDataReader FindLiveReader(SqlCommand command) {
SqlDataReader reader = null;
SqlReferenceCollection referenceCollection = (SqlReferenceCollection)ReferenceCollection;
if (null != referenceCollection) {
reader = referenceCollection.FindLiveReader(command);
}
return reader;
}
abstract protected byte[] GetDTCAddress();
static private byte[] GetTransactionCookie(SysTx.Transaction transaction, byte[] whereAbouts) {
byte[] transactionCookie = null;
if (null != transaction) {
transactionCookie = SysTx.TransactionInterop.GetExportCookie(transaction, whereAbouts);
}
return transactionCookie;
}
virtual protected void InternalDeactivate() {
}
internal void OnError(SqlException exception, bool breakConnection) {
if (breakConnection)
DoomThisConnection();
if (null != Connection) {
Connection.OnError(exception, breakConnection);
}
else if (exception.Class >= TdsEnums.MIN_ERROR_CLASS) {
// It is an error, and should be thrown. Class of TdsEnums.MIN_ERROR_CLASS
// or above is an error, below TdsEnums.MIN_ERROR_CLASS denotes an info message.
throw exception;
}
}
abstract protected void PropagateTransactionCookie(byte[] transactionCookie);
abstract internal void RemovePreparedCommand(SqlCommand cmd);
abstract internal void ValidateConnectionForExecute(SqlCommand command);
// This validation step MUST be done after locking the connection to guarantee we don't
// accidentally execute after the transaction has completed on a different thread, causing us to unwittingly
// execute in auto-commit mode.
internal void ValidateTransaction() {
if (RequireExplicitTransactionUnbind) {
// If we have a system transaction, check that transaction is active and is the current transaction
if (null != InternalEnlistedTransaction) {
SysTx.Transaction currentTran = SysTx.Transaction.Current;
if (SysTx.TransactionStatus.Active != InternalEnlistedTransaction.TransactionInformation.Status ||
null == currentTran ||
!InternalEnlistedTransaction.Equals(currentTran)) {
throw ADP.TransactionConnectionMismatch();
}
}
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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