//
// Tries to take ownership of a file lock.
//
private static FileLock WaitInternal(string name, int timeout)
{
var fileLock = BuildFileLock(name);
try
{
if (timeout != 0 && timeout != -1)
{
throw new NotImplementedException("FileLock.Wait() is implemented only for timeouts 0 or -1.");
}
var overlapped = new NativeOverlapped();
bool hasHandle = NativeLockFile.LockFileEx(
fileLock.SafeFileHandle,
NativeLockFile.LOCKFILE_EXCLUSIVE_LOCK | (timeout == 0 ? NativeLockFile.LOCKFILE_FAIL_IMMEDIATELY : 0),
reserved: 0,
countLow: uint.MaxValue,
countHigh: uint.MaxValue,
ref overlapped);
return(!hasHandle ? null : new FileLock(fileLock));
}
catch (AbandonedMutexException)
{
return(new FileLock(fileLock));
}
/// <summary>
/// Releases the file lock.
/// </summary>
public void Dispose()
{
if (lockFile is not null)
{
var overlapped = new NativeOverlapped();
NativeLockFile.UnlockFileEx(lockFile.SafeFileHandle, 0, uint.MaxValue, uint.MaxValue, ref overlapped);
lockFile.Dispose();
// Try to delete the file
// Ideally we would use FileOptions.DeleteOnClose, but it doesn't seem to work well with FileShare for second instance
try
{
File.Delete(lockFile.Name);
}
catch { }
lockFile = null;
}
}
/// <summary>
/// Tries to take ownership of the file lock within a given delay.
/// </summary>
/// <param name="name">A unique name identifying the file lock.</param>
/// <param name="millisecondsTimeout">The maximum delay to wait before returning, in milliseconds.</param>
/// <returns>A new instance of <see cref="FileLock"/> if the ownership could be taken, <c>null</c> otherwise.</returns>
/// <remarks>
/// The returned <see cref="FileLock"/> must be disposed to release the file lock.
/// Calling this method with 0 for <see paramref="millisecondsTimeout"/> is equivalent to call <see cref="TryLock"/>.
/// Calling this method with a negative value for <see paramref="millisecondsTimeout"/> is equivalent to call <see cref="Wait(string)"/>.
/// </remarks>
public static FileLock Wait(string name, int millisecondsTimeout)
{
var fileLock = BuildFileLock(name);
try
{
if (millisecondsTimeout != 0 && millisecondsTimeout != -1)
{
throw new NotImplementedException("GlobalMutex.Wait() is implemented only for millisecondsTimeout 0 or -1");
}
var overlapped = new NativeOverlapped();
bool hasHandle = NativeLockFile.LockFileEx(fileLock.SafeFileHandle, NativeLockFile.LOCKFILE_EXCLUSIVE_LOCK | (millisecondsTimeout == 0 ? NativeLockFile.LOCKFILE_FAIL_IMMEDIATELY : 0), 0, uint.MaxValue, uint.MaxValue, ref overlapped);
return(hasHandle == false ? null : new FileLock(fileLock));
}
catch (AbandonedMutexException)
{
return(new FileLock(fileLock));
}
}