/// <summary>
/// create new rec lock then waitting
/// </summary>
/// <param name="ctx"></param>
/// <param name="entry"></param>
/// <returns></returns>
private DBResult CreateRecLockForWait(ref LockContext ctx, out LockEntry entry)
{
var recEntry = CreateRecLock(ref ctx);
if (!recEntry.IsWaiting)
{
recEntry.Flags |= LockFlags.Waiting;
}
entry = recEntry;
entry.Transaction.WaitLock = recEntry;
entry.Transaction.State = TransactionState.Waitting;
//check dead-lock
if (IsCausedDeadLock(recEntry))
{
entry.Flags &= ~LockFlags.Waiting;
entry.SetBit(ctx.RecordIndex, 0);
entry.Transaction.WaitLock = null;
return(DBResult.DeadLock);
}
entry.Transaction.WaitEvent.Reset();
return(DBResult.WaitLock);
}
/// <summary>
/// create a new rec-lock
/// </summary>
/// <param name="ctx"></param>
/// <returns></returns>
private LockEntry CreateRecLock(ref LockContext ctx)
{
if (!RecLocks.TryGetValue(ctx.Page, out var list))
{
list = new LinkedList <LockEntry>();
RecLocks[ctx.Page] = list;;
}
var tx = ctx.Transaction;
var entry = new LockEntry(ctx.Page, ctx.Flags, ctx.RecordCount);
if (entry.IsWaiting)
{
tx.WaitLock = entry;
}
list.AddLast(entry);
tx.Locks.AddLast(entry);
entry.GNode = list.Last;
entry.TNode = tx.Locks.Last;
entry.Index = ctx.Index;
entry.Transaction = ctx.Transaction;
entry.Thread = Thread.CurrentThread.ManagedThreadId;
entry.SetBit(ctx.RecordIndex, 1);
return(entry);
}
