public void DecreaseLockUse(bool decreaseToZero, string lockId)
{
if (FileStream == null)
{
throw new InvalidOperationException("You cannot decrease lock use when no file stream has been assgined.");
}
var decreaseLockUseLocker = this.decreaseLockUseLocker;
if (decreaseLockUseLocker == null)
{
return;
}
// Why surround by lock?
// There is a race condition, when number of file lock uses
// is decrased to 0. It may not have invalidated the file
// stream yet. Now it can happen that the number of file lock
// uses is increased to 1 due to file lock, but right after another
// file unlock is about to decrease the number again to 0.
// There is the possiblity that the actual file lock gets released
// two times accidentally.
lock (decreaseLockUseLocker) {
if (!(FileStream.CanRead || FileStream.CanWrite))
{
Trace.WriteLine($"{FileLocker.CurrentThreadWithLockIdPrefix(lockId)} Lock use has been invalidated before. Skip decreasing lock use.", FileLocker.TraceCategory);
return;
}
var locksInUse = fileLocker.DecreaseLockUse(decreaseToZero, lockId);
if (0 == locksInUse)
{
this.decreaseLockUseLocker = null;
}
}
}
public FileLockContext(FileLocker fileLocker, object decreaseLockUseLocker, FileStream fileStream)
: this(fileLocker, decreaseLockUseLocker)
{
FileStream = fileStream ?? throw new ArgumentNullException(nameof(fileStream));
}
public FileLockContext(FileLocker fileLocker, object decreaseLockUseLocker, Exception error, ManualResetEvent errorUnlockDone)
: this(fileLocker, decreaseLockUseLocker)
{
Error = error ?? throw new ArgumentNullException(nameof(error));
ErrorUnlockDone = errorUnlockDone ?? throw new ArgumentNullException(nameof(errorUnlockDone));
}
private FileLockContext(FileLocker fileLocker, object decreaseLockUseLocker)
{
this.fileLocker = fileLocker ?? throw new ArgumentNullException(nameof(fileLocker));
this.decreaseLockUseLocker = decreaseLockUseLocker;
}