/// <summary>
/// Prevents write operations from deadlocking by throwing a <see cref="TimeoutException"/> if <see cref="WriteWaitEvent"/> is not available
/// within <see cref="ReadWriteTimeout"/>.
/// </summary>
private void WriteWait()
{
if (!WriteWaitEvent.WaitOne(ReadWriteTimeout))
{
throw new TimeoutException(RS.WriteOperationTimedOut);
}
}
/// <summary>
/// Prevents write operations from deadlocking by throwing a TimeoutException if the WriteWaitEvent is not available within <see cref="ReadWriteTimeout"/> milliseconds
/// </summary>
private void WriteWait()
{
if (!WriteWaitEvent.WaitOne(ReadWriteTimeout))
{
throw new TimeoutException("The write operation timed out waiting for the write lock WaitEvent. Check your usage of AcquireWriteLock/ReleaseWriteLock and AcquireReadLock/ReleaseReadLock.");
}
}
/// <summary>
/// Blocks the current thread until it is able to acquire a write lock. If successful all subsequent reads will be blocked until after a call to <see cref="ReleaseWriteLock"/>.
/// </summary>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or System.Threading.Timeout.Infinite (-1) to wait indefinitely.</param>
/// <returns>true if the write lock was able to be acquired, otherwise false.</returns>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a negative number other than -1, which represents an infinite time-out.</exception>
/// <remarks>If <paramref name="millisecondsTimeout"/> is <see cref="System.Threading.Timeout.Infinite" /> (-1), then attempting to acquire a write lock after acquiring a read lock on the same thread will result in a deadlock.</remarks>
public bool AcquireWriteLock(int millisecondsTimeout = System.Threading.Timeout.Infinite)
{
if (!WriteWaitEvent.WaitOne(millisecondsTimeout))
{
return(false);
}
ReadWaitEvent.Reset();
return(true);
}
/// <summary>
/// Blocks the current thread until it is able to acquire a read lock. If successful, all subsequent writes will be blocked until after a
/// call to <see cref="ReleaseReadLock"/>.
/// </summary>
/// <param name="millisecondsTimeout">The number of milliseconds to wait, or <see cref="Timeout.Infinite" /> to wait indefinitely.</param>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="millisecondsTimeout"/> is a negative number other than -1, which represents an infinite time-out.</exception>
/// <returns>`true` if the read lock was acquired successfully. Otherwise, `false`.</returns>
/// <remarks>
/// If <paramref name="millisecondsTimeout"/> is <see cref="Timeout.Infinite" />, then attempting to acquire a read lock after acquiring a write lock
/// on the same thread will result in a deadlock.
/// </remarks>
public bool AcquireReadLock(int millisecondsTimeout = Timeout.Infinite)
{
if (!ReadWaitEvent.WaitOne(millisecondsTimeout))
{
return(false);
}
WriteWaitEvent.Reset();
return(true);
}
/// <summary>
/// Releases the current read lock, allowing all blocked writes to continue.
/// </summary>
public void ReleaseReadLock()
{
WriteWaitEvent.Set();
}
/// <summary>
/// Prepares an IntPtr to the buffer position and calls <paramref name="writeFunc"/> to perform the writing.
/// </summary>
/// <param name="writeFunc">A function used to write to the buffer. The IntPtr parameter is a pointer to the buffer offset by <paramref name="bufferPosition"/>.</param>
/// <param name="bufferPosition">The offset within the buffer region to start writing from.</param>
protected override void Write(Action <IntPtr> writeFunc, long bufferPosition = 0)
{
WriteWaitEvent.WaitOne();
base.Write(writeFunc, bufferPosition);
}
/// <summary>
/// Writes <paramref name="length"/> bytes from the <paramref name="ptr"/> into the shared memory buffer.
/// </summary>
/// <param name="ptr">A managed pointer to the memory location to be copied into the buffer</param>
/// <param name="length">The number of bytes to be copied</param>
/// <param name="bufferPosition">The offset within the buffer region of the shared memory to write to.</param>
protected override void Write(IntPtr ptr, int length, long bufferPosition = 0)
{
WriteWaitEvent.WaitOne();
base.Write(ptr, length, bufferPosition);
}
/// <summary>
/// Writes an array of <typeparamref name="T"/> into the buffer
/// </summary>
/// <typeparam name="T">A structure type</typeparam>
/// <param name="buffer">An array of <typeparamref name="T"/> to be written. The length of this array controls the number of elements to be written.</param>
/// <param name="bufferPosition">The offset within the buffer region of the shared memory to write to.</param>
protected override void Write <T>(T[] buffer, long bufferPosition = 0)
{
WriteWaitEvent.WaitOne();
base.Write <T>(buffer, bufferPosition);
}
/// <summary>
/// Writes an instance of <typeparamref name="T"/> into the buffer
/// </summary>
/// <typeparam name="T">A structure type</typeparam>
/// <param name="data">A reference to an instance of <typeparamref name="T"/> to be written</param>
/// <param name="bufferPosition">The offset within the buffer region of the shared memory to write to.</param>
protected override void Write <T>(ref T data, long bufferPosition = 0)
{
WriteWaitEvent.WaitOne();
base.Write <T>(ref data, bufferPosition);
}
