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// Copyright (c) 2004-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most
// MySQL Connectors. There are special exceptions to the terms and
// conditions of the GPLv2 as it is applied to this software, see the
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
using System;
using System.Transactions;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Threading;
namespace MySql.Data.MySqlClient
{
/// <summary>
/// Represents a single(not nested) TransactionScope
/// </summary>
internal class MySqlTransactionScope
{
public MySqlConnection connection;
public Transaction baseTransaction;
public MySqlTransaction simpleTransaction;
public int rollbackThreadId;
public MySqlTransactionScope(MySqlConnection con, Transaction trans,
MySqlTransaction simpleTransaction)
{
connection = con;
baseTransaction = trans;
this.simpleTransaction = simpleTransaction;
}
public void Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
{
// prevent commands in main thread to run concurrently
Driver driver = connection.driver;
lock (driver)
{
rollbackThreadId = Thread.CurrentThread.ManagedThreadId;
while (connection.Reader != null)
{
// wait for reader to finish. Maybe we should not wait
// forever and cancel it after some time?
System.Threading.Thread.Sleep(100);
}
simpleTransaction.Rollback();
singlePhaseEnlistment.Aborted();
DriverTransactionManager.RemoveDriverInTransaction(baseTransaction);
driver.CurrentTransaction = null;
if (connection.State == ConnectionState.Closed)
connection.CloseFully();
rollbackThreadId = 0;
}
}
public void SinglePhaseCommit(SinglePhaseEnlistment singlePhaseEnlistment)
{
simpleTransaction.Commit();
singlePhaseEnlistment.Committed();
DriverTransactionManager.RemoveDriverInTransaction(baseTransaction);
connection.driver.CurrentTransaction = null;
if (connection.State == ConnectionState.Closed)
connection.CloseFully();
}
}
internal sealed class MySqlPromotableTransaction : IPromotableSinglePhaseNotification, ITransactionPromoter
{
// Per-thread stack to manage nested transaction scopes
[ThreadStatic]
static Stack<MySqlTransactionScope> globalScopeStack;
MySqlConnection connection;
Transaction baseTransaction;
Stack<MySqlTransactionScope> scopeStack;
public MySqlPromotableTransaction(MySqlConnection connection, Transaction baseTransaction)
{
this.connection = connection;
this.baseTransaction = baseTransaction;
}
public Transaction BaseTransaction
{
get
{
if (scopeStack.Count > 0)
return scopeStack.Peek().baseTransaction;
else
return null;
}
}
public bool InRollback
{
get
{
if (scopeStack.Count > 0)
{
MySqlTransactionScope currentScope = scopeStack.Peek();
if (currentScope.rollbackThreadId == Thread.CurrentThread.ManagedThreadId)
{
return true;
}
}
return false;
}
}
void IPromotableSinglePhaseNotification.Initialize()
{
string valueName = Enum.GetName(
typeof(System.Transactions.IsolationLevel), baseTransaction.IsolationLevel);
System.Data.IsolationLevel dataLevel = (System.Data.IsolationLevel)Enum.Parse(
typeof(System.Data.IsolationLevel), valueName);
MySqlTransaction simpleTransaction = connection.BeginTransaction(dataLevel);
// We need to save the per-thread scope stack locally.
// We cannot always use thread static variable in rollback: when scope
// times out, rollback is issued by another thread.
if (globalScopeStack == null)
{
globalScopeStack = new Stack<MySqlTransactionScope>();
}
scopeStack = globalScopeStack;
scopeStack.Push(new MySqlTransactionScope(connection, baseTransaction,
simpleTransaction));
}
void IPromotableSinglePhaseNotification.Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
{
MySqlTransactionScope current = scopeStack.Peek();
current.Rollback(singlePhaseEnlistment);
scopeStack.Pop();
}
void IPromotableSinglePhaseNotification.SinglePhaseCommit(SinglePhaseEnlistment singlePhaseEnlistment)
{
scopeStack.Pop().SinglePhaseCommit(singlePhaseEnlistment);
}
byte[] ITransactionPromoter.Promote()
{
throw new NotSupportedException();
}
}
internal class DriverTransactionManager
{
private static Hashtable driversInUse = new Hashtable();
public static Driver GetDriverInTransaction(Transaction transaction)
{
lock (driversInUse.SyncRoot)
{
Driver d = (Driver)driversInUse[transaction.GetHashCode()];
return d;
}
}
public static void SetDriverInTransaction(Driver driver)
{
lock (driversInUse.SyncRoot)
{
driversInUse[driver.CurrentTransaction.BaseTransaction.GetHashCode()] = driver;
}
}
public static void RemoveDriverInTransaction(Transaction transaction)
{
lock (driversInUse.SyncRoot)
{
driversInUse.Remove(transaction.GetHashCode());
}
}
}
}
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