WaitHandle.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Threading / WaitHandle.cs / 3 / WaitHandle.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*==============================================================================
** 
** Class: WaitHandle    (this name is NOT definitive) 
**
** 
** Purpose: Class to represent all synchronization objects in the runtime (that allow multiple wait)
**
**
=============================================================================*/ 

namespace System.Threading { 
    using System.Threading; 
    using System.Runtime.Remoting;
    using System; 
    using System.Security.Permissions;
    using System.Runtime.CompilerServices;
    using Microsoft.Win32.SafeHandles;
    using System.Runtime.Versioning; 
    using System.Runtime.ConstrainedExecution;
    using Win32Native = Microsoft.Win32.Win32Native; 
 
[System.Runtime.InteropServices.ComVisible(true)]
    public abstract class WaitHandle : MarshalByRefObject, IDisposable 
    {
        public const int WaitTimeout = 0x102;

        private const int MAX_WAITHANDLES = 64; 

#pragma warning disable 414  // Field is not used from managed. 
        private IntPtr waitHandle;  // !!! DO NOT MOVE THIS FIELD. (See defn of WAITHANDLEREF in object.h - has hardcoded access to this field.) 
#pragma warning restore 414
 
        internal SafeWaitHandle safeWaitHandle;

        internal bool hasThreadAffinity;
 
        protected static readonly IntPtr InvalidHandle = Win32Native.INVALID_HANDLE_VALUE;
        private const int WAIT_OBJECT_0 = 0; 
        private const int WAIT_ABANDONED = 0x80; 
        private const int WAIT_FAILED = 0x7FFFFFFF;
        private const int ERROR_TOO_MANY_POSTS = 0x12A; 

        protected WaitHandle()
        { safeWaitHandle = null;
          waitHandle = InvalidHandle; 
          hasThreadAffinity = false; }
 
 
        [Obsolete("Use the SafeWaitHandle property instead.")]
        public virtual IntPtr Handle 
        {
             [ResourceExposure(ResourceScope.Machine)]
             [ResourceConsumption(ResourceScope.Machine)]
             get { return safeWaitHandle == null ? InvalidHandle : safeWaitHandle.DangerousGetHandle();} 

             [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)] 
             [SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags=SecurityPermissionFlag.UnmanagedCode)] 
             [ResourceExposure(ResourceScope.Machine)]
             [ResourceConsumption(ResourceScope.Machine)] 
             set {
                 if (value == InvalidHandle) {
                     // This line leaks a handle.  However, it's currently
                     // not perfectly clear what the right behavior is here 
                     // anyways.  This preserves Everett behavior.  We should
                     // ideally do these things: 
                     // *) Expose a settable SafeHandle property on WaitHandle. 
                     // *) Expose a settable OwnsHandle property on SafeHandle.
                     // We're looking into this.   -- [....] 
                     safeWaitHandle.SetHandleAsInvalid();
                     safeWaitHandle = null;
                 }
                 else { 
                     safeWaitHandle = new SafeWaitHandle(value, true);
                 } 
                 waitHandle = value; 
             }
        } 


        public SafeWaitHandle SafeWaitHandle
        { 
             [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)]
             [SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags=SecurityPermissionFlag.UnmanagedCode)] 
             [ResourceExposure(ResourceScope.Machine)] 
             [ResourceConsumption(ResourceScope.Machine)]
             [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)] 
             get {
                if (safeWaitHandle == null) {
                    safeWaitHandle = new SafeWaitHandle(InvalidHandle, false);
                } 
                return safeWaitHandle;
             } 
 
             [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)]
             [SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags=SecurityPermissionFlag.UnmanagedCode)] 
             [ResourceExposure(ResourceScope.Machine)]
             [ResourceConsumption(ResourceScope.Machine)]
             [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
             set { 
                 // Set safeWaitHandle and waitHandle in a CER so we won't take
                 // a thread abort between the statements and leave the wait 
                 // handle in an invalid state. Note this routine is not thread 
                 // safe however.
                 RuntimeHelpers.PrepareConstrainedRegions(); 
                 try {} finally {
                     if (value == null) {
                         safeWaitHandle = null;
                         waitHandle = InvalidHandle; 
                     }
                     else { 
                         safeWaitHandle = value; 
                         waitHandle = safeWaitHandle.DangerousGetHandle();
                     } 
                 }
             }
        }
 
        // Assembly-private version that doesn't do a security check.  Reduces the
        // number of link-time security checks when reading & writing to a file, 
        // and helps avoid a link time check while initializing security (If you 
        // call a Serialization method that requires security before security
        // has started up, the link time check will start up security, run 
        // serialization code for some security attribute stuff, call into
        // FileStream, which will then call Sethandle, which requires a link time
        // security check.).  While security has fixed that problem, we still
        // don't need to do a linktime check here. 
        [ResourceExposure(ResourceScope.Machine)]
        [ResourceConsumption(ResourceScope.Machine)] 
        internal void SetHandleInternal(SafeWaitHandle handle) 
        {
            safeWaitHandle = handle; 
            waitHandle = handle.DangerousGetHandle();
        }

        public virtual bool WaitOne (int millisecondsTimeout, bool exitContext) 
        {
            if (millisecondsTimeout < -1) 
            { 
                throw new ArgumentOutOfRangeException("millisecondsTimeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1"));
            } 
            return  WaitOne((long)millisecondsTimeout,exitContext);
        }

        public virtual bool WaitOne (TimeSpan timeout, bool exitContext) 
        {
            long tm = (long)timeout.TotalMilliseconds; 
            if (-1 > tm || (long) Int32.MaxValue < tm) 
            {
                throw new ArgumentOutOfRangeException("timeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1")); 
            }
            return WaitOne(tm,exitContext);
        }
 
        public virtual bool WaitOne ()
        { 
            //Infinite Timeout 
            return  WaitOne(-1,false);
        } 

        private bool WaitOne(long timeout, bool exitContext)
        {
            if (safeWaitHandle == null) 
            {
                throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic")); 
            } 
            int ret = WaitOneNative(safeWaitHandle,(uint)timeout,hasThreadAffinity,exitContext);
            if (ret == WAIT_ABANDONED) 
            {
                throw new AbandonedMutexException();
            }
            return (ret != WaitTimeout); 
        }
 
 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        private static extern int WaitOneNative (SafeWaitHandle waitHandle, uint millisecondsTimeout, bool hasThreadAffinity, bool exitContext); 

        /*=======================================================================
        ** Waits for signal from all the objects.
        ** timeout indicates how long to wait before the method returns. 
        ** This method will return either when all the object have been pulsed
        ** or timeout milliseonds have elapsed. 
        ** If exitContext is true then the synchronization domain for the context 
        ** (if in a synchronized context) is exited before the wait and reacquired
        ========================================================================*/ 

        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        private static extern int WaitMultiple(WaitHandle[] waitHandles, int millisecondsTimeout, bool exitContext, bool WaitAll); 

 
        public static bool WaitAll(WaitHandle[] waitHandles, int millisecondsTimeout, bool exitContext) 
        {
            if (waitHandles==null || waitHandles.Length == 0) 
            {
                throw new ArgumentNullException("waitHandles");
            }
            if (waitHandles.Length > MAX_WAITHANDLES) 
            {
                throw new NotSupportedException(Environment.GetResourceString("NotSupported_MaxWaitHandles")); 
            } 
            if (-1 > millisecondsTimeout)
            { 
                throw new ArgumentOutOfRangeException("millisecondsTimeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1"));
            }
            WaitHandle[] internalWaitHandles = new WaitHandle[waitHandles.Length];
            for (int i = 0; i < waitHandles.Length; i ++) 
            {
                WaitHandle waitHandle = waitHandles[i]; 
 
                if (waitHandle == null)
                    throw new ArgumentNullException(Environment.GetResourceString("ArgumentNull_ArrayElement")); 

                if (RemotingServices.IsTransparentProxy(waitHandle))
                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_WaitOnTransparentProxy"));
 
                internalWaitHandles[i] = waitHandle;
            } 
#if _DEBUG 
            // make sure we do not use waitHandles any more.
            waitHandles = null; 
#endif
            int ret = WaitMultiple(internalWaitHandles, millisecondsTimeout, exitContext, true /* waitall*/ );
            if ((WAIT_ABANDONED <= ret) && (WAIT_ABANDONED+internalWaitHandles.Length > ret))
            { 
                //In the case of WaitAll the OS will only provide the
                //    information that mutex was abandoned. 
                //    It won't tell us which one.  So we can't set the Index or provide access to the Mutex 
                throw new AbandonedMutexException();
            } 
            for (int i = 0; i < internalWaitHandles.Length; i ++)
            {
                GC.KeepAlive (internalWaitHandles[i]);
            } 
            return (ret != WaitTimeout);
        } 
 
        public static bool WaitAll(
                                    WaitHandle[] waitHandles, 
                                    TimeSpan timeout,
                                    bool exitContext)
        {
            long tm = (long)timeout.TotalMilliseconds; 
            if (-1 > tm || (long) Int32.MaxValue < tm)
            { 
                throw new ArgumentOutOfRangeException("timeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1")); 
            }
            return WaitAll(waitHandles,(int)tm, exitContext); 
        }


        /*======================================================================= 
        ** Shorthand for WaitAll with timeout = Timeout.Infinite and exitContext = true
        ========================================================================*/ 
        public static bool WaitAll(WaitHandle[] waitHandles) 
        {
            return WaitAll(waitHandles, Timeout.Infinite, true); 
        }

        /*=======================================================================
        ** Waits for notification from any of the objects. 
        ** timeout indicates how long to wait before the method returns.
        ** This method will return either when either one of the object have been 
        ** signalled or timeout milliseonds have elapsed. 
        ** If exitContext is true then the synchronization domain for the context
        ** (if in a synchronized context) is exited before the wait and reacquired 
        ========================================================================*/

        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        public static int WaitAny(WaitHandle[] waitHandles, int millisecondsTimeout, bool exitContext) 
        {
            if (waitHandles==null) 
            { 
                throw new ArgumentNullException("waitHandles");
            } 
            if (MAX_WAITHANDLES < waitHandles.Length)
            {
                throw new NotSupportedException(Environment.GetResourceString("NotSupported_MaxWaitHandles"));
            } 
            if (-1 > millisecondsTimeout)
            { 
                throw new ArgumentOutOfRangeException("millisecondsTimeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1")); 
            }
            WaitHandle[] internalWaitHandles = new WaitHandle[waitHandles.Length]; 
            for (int i = 0; i < waitHandles.Length; i ++)
            {
                WaitHandle waitHandle = waitHandles[i];
 
                if (waitHandle == null)
                    throw new ArgumentNullException(Environment.GetResourceString("ArgumentNull_ArrayElement")); 
 
                if (RemotingServices.IsTransparentProxy(waitHandle))
                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_WaitOnTransparentProxy")); 

                internalWaitHandles[i] = waitHandle;
            }
#if _DEBUG 
            // make sure we do not use waitHandles any more.
            waitHandles = null; 
#endif 
            int ret = WaitMultiple(internalWaitHandles, millisecondsTimeout, exitContext, false /* waitany*/ );
            for (int i = 0; i < internalWaitHandles.Length; i ++) 
            {
                GC.KeepAlive (internalWaitHandles[i]);
            }
            if ((WAIT_ABANDONED <= ret) && (WAIT_ABANDONED+internalWaitHandles.Length > ret)) 
            {
                int mutexIndex = ret -WAIT_ABANDONED; 
                if(0 <= mutexIndex && mutexIndex < internalWaitHandles.Length) 
                {
                    throw new AbandonedMutexException(mutexIndex,internalWaitHandles[mutexIndex]); 
                }
                else
                {
                    throw new AbandonedMutexException(); 
                }
            } 
            else 
                return ret;
 
        }

        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        public static int WaitAny( 
                                    WaitHandle[] waitHandles,
                                    TimeSpan timeout, 
                                    bool exitContext) 
        {
            long tm = (long)timeout.TotalMilliseconds; 
            if (-1 > tm || (long) Int32.MaxValue < tm)
            {
                throw new ArgumentOutOfRangeException("timeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1"));
            } 
            return WaitAny(waitHandles,(int)tm, exitContext);
        } 
 
        /*========================================================================
        ** Shorthand for WaitAny with timeout = Timeout.Infinite and exitContext = true 
        ========================================================================*/
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        public static int WaitAny(WaitHandle[] waitHandles)
        { 
            return WaitAny(waitHandles, Timeout.Infinite, true);
        } 
 
#if !FEATURE_PAL
        /*================================================= 
        ==
        ==  SignalAndWait
        ==
        ==================================================*/ 

        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        private static extern int SignalAndWaitOne(SafeWaitHandle waitHandleToSignal,SafeWaitHandle waitHandleToWaitOn, int millisecondsTimeout, 
                                            bool hasThreadAffinity,  bool exitContext);
 
        public static bool SignalAndWait(
                                        WaitHandle toSignal,
                                        WaitHandle toWaitOn)
        { 
            return SignalAndWait(toSignal,toWaitOn,-1,false);
        } 
 
        public static bool SignalAndWait(
                                        WaitHandle toSignal, 
                                        WaitHandle toWaitOn,
                                        TimeSpan timeout,
                                        bool exitContext)
        { 
            long tm = (long)timeout.TotalMilliseconds;
            if (-1 > tm || (long) Int32.MaxValue < tm) 
            { 
                throw new ArgumentOutOfRangeException("timeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1"));
            } 
            return SignalAndWait(toSignal,toWaitOn,(int)tm,exitContext);
        }

        public static bool SignalAndWait( 
                                        WaitHandle toSignal,
                                        WaitHandle toWaitOn, 
                                        int millisecondsTimeout, 
                                        bool exitContext)
        { 
            if((Environment.OSInfo & Environment.OSName.Win9x) != 0)
                throw new PlatformNotSupportedException(Environment.GetResourceString("PlatformNotSupported_Win9x"));

            if(null == toSignal) 
            {
                throw new ArgumentNullException("toSignal"); 
            } 
            if(null == toWaitOn)
            { 
                throw new ArgumentNullException("toWaitOn");
            }
            if (-1 > millisecondsTimeout)
            { 
                throw new ArgumentOutOfRangeException("millisecondsTimeout", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegOrNegative1"));
            } 
 
            int ret = SignalAndWaitOne(toSignal.safeWaitHandle,toWaitOn.safeWaitHandle,millisecondsTimeout,
                                toWaitOn.hasThreadAffinity,exitContext); 

            if(WAIT_FAILED != ret  && toSignal.hasThreadAffinity)
            {
                Thread.EndCriticalRegion(); 
                Thread.EndThreadAffinity();
            } 
 
            if(WAIT_ABANDONED == ret)
            { 
                throw new AbandonedMutexException();
            }

            if(ERROR_TOO_MANY_POSTS == ret) 
            {
                throw new InvalidOperationException(Environment.GetResourceString("Threading.WaitHandleTooManyPosts")); 
            } 

            //Object was signaled 
            if(WAIT_OBJECT_0 == ret)
            {
                return true;
            } 

            //Timeout 
            return false; 
        }
#endif 

        public virtual void Close()
        {
            Dispose(true); 
            GC.nativeSuppressFinalize(this);
        } 
 
        protected virtual void Dispose(bool explicitDisposing)
        { 
            if (safeWaitHandle != null) {
                safeWaitHandle.Close();
            }
        } 

        ///  
        void IDisposable.Dispose() 
        {
            Dispose(true); 
            GC.nativeSuppressFinalize(this);
        }
    }
}

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