/// <summary>
/// Attempts go get a write lock. Returns a list of transaction holding the lock, if it doesnt
/// include the given transaction, the lock failed. This also checks to see if there is a read
/// lock and will return those transaction too.
/// </summary>
/// <param name="tempTransaction">The temp transaction.</param>
/// <returns>List of transaction holding the lock.</returns>
public List<Transaction> GetWriteLock(Transaction tempTransaction)
{
//we cant get a write lock if there are write lock holders
//so lets check that first
if (IsReadLocked)
{
//maybe the same transaction holds the only read lock
//in which case we can give it the write lock
if (ReadLockHolders.Count == 1 && ReadLockHolders.Contains(tempTransaction))
{
WriteLockHolder = tempTransaction;
tempTransaction.AddLockHeldLocation(Site);
return new List<Transaction> {WriteLockHolder};
}
else //it doesnt, sad panda
{
return ReadLockHolders;
}
}
if (IsWriteLocked)
{
return new List<Transaction> {WriteLockHolder};
}
else
{
WriteLockHolder = tempTransaction;
tempTransaction.AddLockHeldLocation(Site);
return new List<Transaction> {WriteLockHolder};
}
}
/// <summary>
/// Attempts to get a read lock. Returns a list of transactions holding the lock,
/// if it doesnt include the given transaction, the lock failed. This also
/// check to see if there is a write lock and will return that transaction too.
/// </summary>
/// <param name="tempTransaction">The temp transaction.</param>
/// <returns>List of transactions holding the lock.</returns>
public List<Transaction> GetReadLock(Transaction tempTransaction)
{
//check to see if the there is currently a write lock
if (IsWriteLocked && !WriteLockHolder.Equals(tempTransaction))
//they don't hold the write lock
return new List<Transaction> {WriteLockHolder};
else if (IsWriteLocked && WriteLockHolder.Equals(tempTransaction))
{
//they do hold the write lock
return new List<Transaction> {WriteLockHolder};
}
//there is no write lock, so add the transaction to the list of read lock holders
if (!ReadLockHolders.Contains(tempTransaction))
{
ReadLockHolders.Add(tempTransaction);
tempTransaction.AddLockHeldLocation(Site);
}
return ReadLockHolders;
}