public async Task <Releaser> AcquireLock(ulong pageId, LockTypeEnum lockType)
{
int lockId = lockManager.LockIdForPage(pageId);
if (lockType != LockTypeEnum.Shared)
{
throw new ReadOnlyTranCantAcquireExLockException();
}
lock (lck)
{
if (locksHeld.ContainsKey(lockId))
{
// Return dummy leaser. You don't really own this lock.
// This probably needs to change.
throw new TranAlreadyHoldingLock();
}
}
var releaser = await lockManager.AcquireLock(lockType, pageId, this.transactionId);
lock (lck)
{
locksHeld.Add(lockId, lockType);
}
releaser.SetReleaseCallback(() => this.ReleaseLock(lockId));
return(releaser);
}
private async Task <Releaser> AcquireLockInternal(ulong pageId, LockTypeEnum lockType, bool forceCallerOwnership)
{
ILockManager lockManager = this.pageManager.GetLockManager();
int lockId = lockManager.LockIdForPage(pageId);
lock (lck)
{
if (locksHeld.ContainsKey(lockId))
{
return(new Releaser());
}
}
var releaser = await lockManager.AcquireLock(lockType, pageId, this.transactionId).ConfigureAwait(continueOnCapturedContext: false);
lock (lck)
{
locksHeld.Add(lockId, lockType);
}
releaser.SetReleaseCallback(() => this.ReleaseLockCallback(lockId));
if (forceCallerOwnership)
{
return(releaser);
}
// TODO: Implement Isolation Level strategy.
if (this.isolationLevel == IsolationLevelEnum.ReadCommitted)
{
// If this is a read lock return to caller.
// If write transaction is the owner.
if (lockType == LockTypeEnum.Shared)
{
return(releaser);
}
else if (lockType == LockTypeEnum.Exclusive)
{
this.myLocks.Add(releaser);
return(new Releaser());
}
else
{
throw new InvalidProgramException();
}
}
else
{
throw new InvalidProgramException();
}
}
public bool AmIHoldingALock(ulong pageId, out LockTypeEnum lockType)
{
ILockManager lockManager = this.pageManager.GetLockManager();
int lockId = lockManager.LockIdForPage(pageId);
lock (lck)
{
if (locksHeld.TryGetValue(lockId, out LockTypeEnum myLock))
{
lockType = myLock;
return(true);
}
}
lockType = LockTypeEnum.Shared;
return(false);
}