SqlWorkflowInstanceStoreLock.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / System.Activities.DurableInstancing / System / Activities / DurableInstancing / SqlWorkflowInstanceStoreLock.cs / 1305376 / SqlWorkflowInstanceStoreLock.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.DurableInstancing 
{
    using System; 
    using System.Collections.Generic; 
    using System.Linq;
    using System.Runtime; 
    using System.Runtime.DurableInstancing;
    using System.Threading;

    class SqlWorkflowInstanceStoreLock 
    {
        bool isBeingModified; 
        Guid lockOwnerId; 
        SqlWorkflowInstanceStore sqlWorkflowInstanceStore;
        WeakReference lockOwnerInstanceHandle; 
        object thisLock;

        public SqlWorkflowInstanceStoreLock(SqlWorkflowInstanceStore sqlWorkflowInstanceStore)
        { 
            this.sqlWorkflowInstanceStore = sqlWorkflowInstanceStore;
            this.thisLock = new object(); 
            this.SurrogateLockOwnerId = -1; 
        }
 
        public PersistenceTask InstanceDetectionTask
        {
            get;
            set; 
        }
 
        public bool IsValid 
        {
            get 
            {
                return IsLockOwnerValid(this.SurrogateLockOwnerId);
            }
        } 

        public bool IsLockOwnerValid(long surrogateLockOwnerId) 
        { 
            return (this.SurrogateLockOwnerId != -1)
                && (surrogateLockOwnerId == this.SurrogateLockOwnerId) 
                    && (this.sqlWorkflowInstanceStore.InstanceOwnersExist);
        }

        public Guid LockOwnerId 
        {
            get 
            { 
                return this.lockOwnerId;
            } 
        }

        public PersistenceTask LockRecoveryTask
        { 
            get;
            set; 
        } 

        public PersistenceTask LockRenewalTask 
        {
            get;
            set;
        } 

        public long SurrogateLockOwnerId 
        { 
            get;
            private set; 
        }

        object ThisLock
        { 
            get
            { 
                return this.thisLock; 
            }
        } 

        public void MarkInstanceOwnerCreated(Guid lockOwnerId, long surrogateLockOwnerId, InstanceHandle lockOwnerInstanceHandle, bool detectRunnableInstances, bool detectActivatableInstances)
        {
            Fx.Assert(this.isBeingModified, "Must have modification lock to mark owner as created"); 
            this.lockOwnerId = lockOwnerId;
            this.SurrogateLockOwnerId = surrogateLockOwnerId; 
            this.lockOwnerInstanceHandle = new WeakReference(lockOwnerInstanceHandle); 

            TimeSpan hostLockRenewalPeriod = this.sqlWorkflowInstanceStore.HostLockRenewalPeriod; 
            TimeSpan runnableInstancesDetectionPeriod = this.sqlWorkflowInstanceStore.RunnableInstancesDetectionPeriod;

            if (detectActivatableInstances)
            { 
                this.InstanceDetectionTask = new DetectActivatableWorkflowsTask(this.sqlWorkflowInstanceStore, this, runnableInstancesDetectionPeriod);
            } 
            else if (detectRunnableInstances) 
            {
                this.InstanceDetectionTask = new DetectRunnableInstancesTask(this.sqlWorkflowInstanceStore, this, runnableInstancesDetectionPeriod); 
            }

            this.LockRenewalTask = new LockRenewalTask(this.sqlWorkflowInstanceStore, this, hostLockRenewalPeriod);
            this.LockRecoveryTask = new LockRecoveryTask(this.sqlWorkflowInstanceStore, this, hostLockRenewalPeriod); 

            if (this.InstanceDetectionTask != null) 
            { 
                this.InstanceDetectionTask.ResetTimer(true);
            } 
            this.LockRenewalTask.ResetTimer(true);
            this.LockRecoveryTask.ResetTimer(true);
        }
 
        public void MarkInstanceOwnerLost(long surrogateLockOwnerId, bool hasModificationLock)
        { 
            if (hasModificationLock) 
            {
                this.MarkInstanceOwnerLost(surrogateLockOwnerId); 
            }
            else
            {
                this.TakeModificationLock(); 
                this.MarkInstanceOwnerLost(surrogateLockOwnerId);
                this.ReturnModificationLock(); 
            } 
        }
 
        public void ReturnModificationLock()
        {
            Fx.Assert(this.isBeingModified, "Must have modification lock to release it!");
            bool lockTaken = false; 

            while (true) 
            { 
                Monitor.Enter(ThisLock, ref lockTaken);
 
                if (lockTaken)
                {
                    this.isBeingModified = false;
                    Monitor.Pulse(ThisLock); 
                    Monitor.Exit(ThisLock);
                    return; 
                } 
            }
        } 

        public void TakeModificationLock()
        {
            bool lockTaken = false; 

            while (true) 
            { 
                Monitor.Enter(ThisLock, ref lockTaken);
 
                if (lockTaken)
                {
                    while (this.isBeingModified)
                    { 
                        Monitor.Wait(ThisLock);
                    } 
 
                    this.isBeingModified = true;
                    Monitor.Exit(ThisLock); 
                    return;
                }
            }
        } 

        void MarkInstanceOwnerLost(long surrogateLockOwnerId) 
        { 
            Fx.Assert(this.isBeingModified, "Must have modification lock to mark owner as lost");
 
            if (this.SurrogateLockOwnerId == surrogateLockOwnerId)
            {
                this.SurrogateLockOwnerId = -1;
                InstanceHandle instanceHandle = this.lockOwnerInstanceHandle.Target as InstanceHandle; 
                if (instanceHandle != null)
                { 
                    instanceHandle.Free(); 
                }
 
                if (this.sqlWorkflowInstanceStore.IsLockRetryEnabled())
                {
                    this.sqlWorkflowInstanceStore.LoadRetryHandler.AbortPendingRetries();
                } 

                if (this.LockRenewalTask != null) 
                { 
                    this.LockRenewalTask.CancelTimer();
                } 

                if (this.LockRecoveryTask != null)
                {
                    this.LockRecoveryTask.CancelTimer(); 
                }
 
                if (this.InstanceDetectionTask != null) 
                {
                    this.InstanceDetectionTask.CancelTimer(); 
                }
            }
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
SqlWorkflowInstanceStoreLock.cs source code in C# .NET

Source code for the .NET framework in C#

Code:

Link Menu
