/// <summary>
/// Blocks if no release is signaled or removes a release signal. Enter a critical section.
/// In theory, this method is often called P() [Dijkstra, dutch: passeeren]
/// </summary>
/// <remarks>This member is thread-safe.</remarks>
public void Acquire()
{
while (true)
{ //looped 0.5s timeout to make blocked threads abortable.
uint res = NTKernel.WaitForSingleObject(handle, interruptReactionTime);
try { System.Threading.Thread.Sleep(0); }
catch (System.Threading.ThreadInterruptedException e)
{
if (res == 0)
{
int previousCount;
NTKernel.ReleaseSemaphore(handle, 1, out previousCount);
}
throw e;
}
if (res == 0)
{
return;
}
if (res != 258)
{
throw new SemaphoreFailedException();
}
}
}
/// <summary>
/// Instanciate a new Inter-Process semaphore.
/// </summary>
/// <param name="name">The semaphore's name.</param>
/// <param name="initial">The initial count of releases signaled.</param>
/// <param name="max">The maximum count of release signaled.</param>
/// <param name="interruptReactionTime">The maximum time [ms] needed to react to interrupts.</param>
public ProcessSemaphore(string name, int initial, int max, int interruptReactionTime)
{
this.interruptReactionTime = (uint)interruptReactionTime;
this.handle = NTKernel.CreateSemaphore(null, initial, max, name);
if (handle == 0)
{
throw new SemaphoreFailedException();
}
}
/// <summary>
/// Signals a release and allows a blocked thread to continue. Leave a critical section.
/// In theory, this method is often called V() [Dijkstra, dutch: vrijgeven]
/// </summary>
/// <remarks>This member is thread-safe.</remarks>
public void Release()
{
int previousCount;
if (!NTKernel.ReleaseSemaphore(handle, 1, out previousCount))
{
throw new SemaphoreFailedException();
}
}
/// <summary>
/// Blocks if no release is signaled or removes a release signal. Enter a critical section.
/// In theory, this method is often called P() [Dijkstra, dutch: passeeren]
/// </summary>
/// <param name="timeout">The maximum blocking time. Usually an Exceptions is thrown if a timeout exceeds.</param>
/// <remarks>This member is thread-safe.</remarks>
public void Acquire(TimeSpan timeout)
{
uint milliseconds = (uint)timeout.TotalMilliseconds;
if (NTKernel.WaitForSingleObject(handle, milliseconds) != 0)
{
throw new SemaphoreFailedException();
}
}
public void Dispose()
{
if (fileMapping != IntPtr.Zero)
{
if (NTKernel.CloseHandle((uint)fileMapping))
{
fileMapping = IntPtr.Zero;
}
}
}
/// <summary>
/// Don't forget to dispose this object before destruction.
/// </summary>
public void Dispose()
{
if (handle != 0)
{
if (NTKernel.CloseHandle(handle))
{
handle = 0;
}
}
}
public void Dispose()
{
if (mappedView != IntPtr.Zero)
{
if (NTKernel.UnmapViewOfFile(mappedView))
{
mappedView = IntPtr.Zero;
}
}
}
/// <summary>
/// Create a view of the memory mapped file, allowing to read/write bytes.
/// </summary>
/// <param name="offset">An optional offset to the file.</param>
/// <param name="size">The size of the view in terms of bytes.</param>
/// <param name="access">Whether you need write access to the view.</param>
/// <returns>A MemoryMappedFileView instance representing the view.</returns>
public MemoryMappedFileView CreateView(int offset, int size, MemoryMappedFileView.ViewAccess access)
{
if (this.access == FileAccess.ReadOnly && access == MemoryMappedFileView.ViewAccess.ReadWrite)
{
throw new ArgumentException("Only read access to views allowed on files without write access", "access");
}
if (offset < 0)
{
throw new ArgumentException("Offset must not be negative", "size");
}
if (size < 0)
{
throw new ArgumentException("Size must not be negative", "size");
}
IntPtr mappedView = NTKernel.MapViewOfFile(fileMapping, (uint)access, 0, (uint)offset, (uint)size);
return(new MemoryMappedFileView(mappedView, size, access));
}
/// <summary>
/// Create a virtual memory mapped file located in the system page file.
/// </summary>
/// <param name="name">The name of the file. Prefix it with "Global\" or "Local\" to control its scope between NT services and user applications in Terminal Server scenarios.</param>
/// <param name="access">Whether you need write access to the file.</param>
/// <param name="size">The preferred size of the file in terms of bytes.</param>
/// <returns>A MemoryMappedFile instance representing the file.</returns>
public static MemoryMappedFile CreateFile(string name, FileAccess access, int size)
{
if (size < 0)
{
throw new ArgumentException("Size must not be negative", "size");
}
//object descriptor = null;
//NTAdvanced.InitializeSecurityDescriptor(out descriptor,1);
//NTAdvanced.SetSecurityDescriptorDacl(ref descriptor,true,null,false);
//NTKernel.SecurityAttributes sa = new NTKernel.SecurityAttributes(descriptor);
IntPtr fileMapping = NTKernel.CreateFileMapping(0xFFFFFFFFu, null, (uint)access, 0, (uint)size, name);
if (fileMapping == IntPtr.Zero)
{
throw new MemoryMappingFailedException();
}
return(new MemoryMappedFile(fileMapping, size, access));
}
