| 0,0 → 1,194 |
|---|
| #if !MONO && !PocketPC |
| #define UseFastResourceLock |
| #endif |
| |
| namespace GMap.NET.Internals |
| { |
| using System; |
| using System.Threading; |
| #if !MONO |
| using System.Runtime.InteropServices; |
| #endif |
| |
| /// <summary> |
| /// custom ReaderWriterLock |
| /// in Vista and later uses integrated Slim Reader/Writer (SRW) Lock |
| /// http://msdn.microsoft.com/en-us/library/aa904937(VS.85).aspx |
| /// http://msdn.microsoft.com/en-us/magazine/cc163405.aspx#S2 |
| /// </summary> |
| public sealed class FastReaderWriterLock : IDisposable |
| { |
| #if !MONO && !PocketPC |
| private static class NativeMethods |
| { |
| // Methods |
| [DllImport("Kernel32", ExactSpelling = true)] |
| internal static extern void AcquireSRWLockExclusive(ref IntPtr srw); |
| [DllImport("Kernel32", ExactSpelling = true)] |
| internal static extern void AcquireSRWLockShared(ref IntPtr srw); |
| [DllImport("Kernel32", ExactSpelling = true)] |
| internal static extern void InitializeSRWLock(out IntPtr srw); |
| [DllImport("Kernel32", ExactSpelling = true)] |
| internal static extern void ReleaseSRWLockExclusive(ref IntPtr srw); |
| [DllImport("Kernel32", ExactSpelling = true)] |
| internal static extern void ReleaseSRWLockShared(ref IntPtr srw); |
| } |
| |
| IntPtr LockSRW = IntPtr.Zero; |
| |
| public FastReaderWriterLock() |
| { |
| if (UseNativeSRWLock) |
| { |
| NativeMethods.InitializeSRWLock(out this.LockSRW); |
| } |
| else |
| { |
| #if UseFastResourceLock |
| pLock = new FastResourceLock(); |
| #endif |
| } |
| } |
| |
| #if UseFastResourceLock |
| ~FastReaderWriterLock() |
| { |
| Dispose(false); |
| } |
| |
| void Dispose(bool disposing) |
| { |
| if (pLock != null) |
| { |
| pLock.Dispose(); |
| pLock = null; |
| } |
| } |
| |
| FastResourceLock pLock; |
| #endif |
| |
| static readonly bool UseNativeSRWLock = Stuff.IsRunningOnVistaOrLater() && IntPtr.Size == 4; // works only in 32-bit mode, any ideas on native 64-bit support? |
| |
| #endif |
| |
| #if !UseFastResourceLock |
| Int32 busy = 0; |
| Int32 readCount = 0; |
| #endif |
| |
| public void AcquireReaderLock() |
| { |
| #if !MONO && !PocketPC |
| if (UseNativeSRWLock) |
| { |
| NativeMethods.AcquireSRWLockShared(ref LockSRW); |
| } |
| else |
| #endif |
| { |
| #if UseFastResourceLock |
| pLock.AcquireShared(); |
| #else |
| Thread.BeginCriticalRegion(); |
| |
| while(Interlocked.CompareExchange(ref busy, 1, 0) != 0) |
| { |
| Thread.Sleep(1); |
| } |
| |
| Interlocked.Increment(ref readCount); |
| |
| // somehow this fix deadlock on heavy reads |
| Thread.Sleep(0); |
| Thread.Sleep(0); |
| Thread.Sleep(0); |
| Thread.Sleep(0); |
| Thread.Sleep(0); |
| Thread.Sleep(0); |
| Thread.Sleep(0); |
| |
| Interlocked.Exchange(ref busy, 0); |
| #endif |
| } |
| } |
| |
| public void ReleaseReaderLock() |
| { |
| #if !MONO && !PocketPC |
| if (UseNativeSRWLock) |
| { |
| NativeMethods.ReleaseSRWLockShared(ref LockSRW); |
| } |
| else |
| #endif |
| { |
| #if UseFastResourceLock |
| pLock.ReleaseShared(); |
| #else |
| Interlocked.Decrement(ref readCount); |
| Thread.EndCriticalRegion(); |
| #endif |
| } |
| } |
| |
| public void AcquireWriterLock() |
| { |
| #if !MONO && !PocketPC |
| if (UseNativeSRWLock) |
| { |
| NativeMethods.AcquireSRWLockExclusive(ref LockSRW); |
| } |
| else |
| #endif |
| { |
| #if UseFastResourceLock |
| pLock.AcquireExclusive(); |
| #else |
| Thread.BeginCriticalRegion(); |
| |
| while(Interlocked.CompareExchange(ref busy, 1, 0) != 0) |
| { |
| Thread.Sleep(1); |
| } |
| |
| while(Interlocked.CompareExchange(ref readCount, 0, 0) != 0) |
| { |
| Thread.Sleep(1); |
| } |
| #endif |
| } |
| } |
| |
| public void ReleaseWriterLock() |
| { |
| #if !MONO && !PocketPC |
| if (UseNativeSRWLock) |
| { |
| NativeMethods.ReleaseSRWLockExclusive(ref LockSRW); |
| } |
| else |
| #endif |
| { |
| #if UseFastResourceLock |
| pLock.ReleaseExclusive(); |
| #else |
| Interlocked.Exchange(ref busy, 0); |
| Thread.EndCriticalRegion(); |
| #endif |
| } |
| } |
| |
| #region IDisposable Members |
| |
| public void Dispose() |
| { |
| #if UseFastResourceLock |
| this.Dispose(true); |
| GC.SuppressFinalize(this); |
| #endif |
| } |
| |
| #endregion |
| } |
| } |