/// <summary>
/// Attempt to upgrade a share lock that we hold to an exclusive lock. </summary>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
//ORIGINAL LINE: private boolean tryUpgradeToExclusiveWithShareLockHeld(org.neo4j.storageengine.api.lock.LockTracer tracer, org.neo4j.storageengine.api.lock.LockWaitEvent priorEvent, org.neo4j.storageengine.api.lock.ResourceType resourceType, long resourceId, SharedLock sharedLock, int tries, long waitStartMillis) throws org.neo4j.storageengine.api.lock.AcquireLockTimeoutException
private bool TryUpgradeToExclusiveWithShareLockHeld(LockTracer tracer, LockWaitEvent priorEvent, ResourceType resourceType, long resourceId, SharedLock sharedLock, int tries, long waitStartMillis)
{
if (sharedLock.TryAcquireUpdateLock(this))
{
LockWaitEvent waitEvent = null;
try
{
// Now we just wait for all clients to release the the share lock
while (sharedLock.NumberOfHolders() > 1)
{
AssertValid(waitStartMillis, resourceType, resourceId);
if (waitEvent == null && priorEvent == null)
{
waitEvent = tracer.WaitForLock(true, resourceType, resourceId);
}
WaitFor(sharedLock, resourceType, resourceId, true, tries++);
}
return(true);
}
catch (Exception e)
{
sharedLock.ReleaseUpdateLock();
if (e is DeadlockDetectedException || e is LockClientStoppedException)
{
throw ( Exception )e;
}
throw new TransactionFailureException("Failed to upgrade shared lock to exclusive: " + sharedLock, e);
}
finally
{
if (waitEvent != null)
{
waitEvent.Close();
}
ClearWaitList();
_waitingForLock = null;
}
}
return(false);
}
/// <summary>
/// Tries to acquire write lock for a given transaction. If
/// <CODE>this.writeCount</CODE> is greater than the currents tx's write
/// count or the read count is greater than the currents tx's read count the
/// transaction has to wait and the <seealso cref="RagManager.checkWaitOn"/> method is
/// invoked for deadlock detection.
/// <p/>
/// If the lock can be acquires the lock count is updated on <CODE>this</CODE>
/// and the transaction lock element (tle).
/// Waiting for a lock can also be terminated. In that case waiting thread will be interrupted and corresponding
/// <seealso cref="org.neo4j.kernel.impl.locking.community.RWLock.TxLockElement"/> will be marked as terminated.
/// In that case lock will not be acquired and false will be return as result of acquisition
/// </summary>
/// <returns> true is lock was acquired, false otherwise </returns>
/// <exception cref="DeadlockDetectedException"> if a deadlock is detected </exception>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
//ORIGINAL LINE: synchronized boolean acquireWriteLock(org.neo4j.storageengine.api.lock.LockTracer tracer, Object tx) throws org.neo4j.kernel.DeadlockDetectedException
internal virtual bool AcquireWriteLock(LockTracer tracer, object tx)
{
lock (this)
{
TxLockElement tle = GetOrCreateLockElement(tx);
LockRequest lockRequest = null;
LockWaitEvent waitEvent = null;
// used to track do we need to add lock request to a waiting queue or we still have it there
bool addLockRequest = true;
try
{
tle.IncrementRequests();
Thread currentThread = currentThread();
long lockAcquisitionTimeBoundary = _clock.millis() + _lockAcquisitionTimeoutMillis;
while (!tle.Terminated && (_totalWriteCount > tle.WriteCount || _totalReadCount > tle.ReadCount))
{
AssertNotExpired(lockAcquisitionTimeBoundary);
_ragManager.checkWaitOn(this, tx);
if (addLockRequest)
{
lockRequest = new LockRequest(tle, WRITE, currentThread);
_waitingThreadList.AddFirst(lockRequest);
}
if (waitEvent == null)
{
waitEvent = tracer.WaitForLock(true, _resource.type(), _resource.resourceId());
}
addLockRequest = WaitUninterruptedly(lockAcquisitionTimeBoundary);
_ragManager.stopWaitOn(this, tx);
}
if (!tle.Terminated)
{
RegisterWriteLockAcquired(tx, tle);
return(true);
}
else
{
// in case if lock element was interrupted and it was never register before
// we need to clean it from lock element map
// if it was register before it will be cleaned up during standard lock release call
if (tle.Requests == 1 && tle.Free)
{
_txLockElementMap.Remove(tx);
}
return(false);
}
}
finally
{
if (waitEvent != null)
{
waitEvent.Close();
}
CleanupWaitingListRequests(lockRequest, tle, addLockRequest);
// for cases when spurious wake up was the reason why we waked up, but also there
// was an interruption as described at 17.2 just clearing interruption flag
interrupted();
// if deadlocked, remove marking so lock is removed when empty
tle.DecrementRequests();
Unmark();
}
}
}
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
//ORIGINAL LINE: public void acquireExclusive(org.neo4j.storageengine.api.lock.LockTracer tracer, org.neo4j.storageengine.api.lock.ResourceType resourceType, long... resourceIds) throws org.neo4j.storageengine.api.lock.AcquireLockTimeoutException
public override void AcquireExclusive(LockTracer tracer, ResourceType resourceType, params long[] resourceIds)
{
_hasLocks = true;
_stateHolder.incrementActiveClients(this);
LockWaitEvent waitEvent = null;
try
{
ConcurrentMap <long, ForsetiLockManager.Lock> lockMap = _lockMaps[resourceType.TypeId()];
MutableLongIntMap heldLocks = _exclusiveLockCounts[resourceType.TypeId()];
foreach (long resourceId in resourceIds)
{
int heldCount = heldLocks.getIfAbsent(resourceId, -1);
if (heldCount != -1)
{
// We already have a lock on this, just increment our local reference counter.
heldLocks.put(resourceId, Math.incrementExact(heldCount));
continue;
}
// Grab the global lock
ForsetiLockManager.Lock existingLock;
int tries = 0;
long waitStartMillis = _clock.millis();
while ((existingLock = lockMap.putIfAbsent(resourceId, _myExclusiveLock)) != null)
{
AssertValid(waitStartMillis, resourceType, resourceId);
// If this is a shared lock:
// Given a grace period of tries (to try and not starve readers), grab an update lock and wait
// for it to convert to an exclusive lock.
if (tries > 50 && existingLock is SharedLock)
{
// Then we should upgrade that lock
SharedLock sharedLock = ( SharedLock )existingLock;
if (TryUpgradeSharedToExclusive(tracer, waitEvent, resourceType, lockMap, resourceId, sharedLock, waitStartMillis))
{
break;
}
}
if (waitEvent == null)
{
waitEvent = tracer.WaitForLock(true, resourceType, resourceId);
}
WaitFor(existingLock, resourceType, resourceId, true, tries++);
}
heldLocks.put(resourceId, 1);
}
}
finally
{
if (waitEvent != null)
{
waitEvent.Close();
}
ClearWaitList();
_waitingForLock = null;
_stateHolder.decrementActiveClients();
}
}
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
//ORIGINAL LINE: public void acquireShared(org.neo4j.storageengine.api.lock.LockTracer tracer, org.neo4j.storageengine.api.lock.ResourceType resourceType, long... resourceIds) throws org.neo4j.storageengine.api.lock.AcquireLockTimeoutException
public override void AcquireShared(LockTracer tracer, ResourceType resourceType, params long[] resourceIds)
{
_hasLocks = true;
_stateHolder.incrementActiveClients(this);
LockWaitEvent waitEvent = null;
try
{
// Grab the global lock map we will be using
ConcurrentMap <long, ForsetiLockManager.Lock> lockMap = _lockMaps[resourceType.TypeId()];
// And grab our local lock maps
MutableLongIntMap heldShareLocks = _sharedLockCounts[resourceType.TypeId()];
MutableLongIntMap heldExclusiveLocks = _exclusiveLockCounts[resourceType.TypeId()];
foreach (long resourceId in resourceIds)
{
// First, check if we already hold this as a shared lock
int heldCount = heldShareLocks.getIfAbsent(resourceId, -1);
if (heldCount != -1)
{
// We already have a lock on this, just increment our local reference counter.
heldShareLocks.put(resourceId, Math.incrementExact(heldCount));
continue;
}
// Second, check if we hold it as an exclusive lock
if (heldExclusiveLocks.containsKey(resourceId))
{
// We already have an exclusive lock, so just leave that in place.
// When the exclusive lock is released, it will be automatically downgraded to a shared lock,
// since we bumped the share lock reference count.
heldShareLocks.put(resourceId, 1);
continue;
}
// We don't hold the lock, so we need to grab it via the global lock map
int tries = 0;
SharedLock mySharedLock = null;
long waitStartMillis = _clock.millis();
// Retry loop
while (true)
{
AssertValid(waitStartMillis, resourceType, resourceId);
// Check if there is a lock for this entity in the map
ForsetiLockManager.Lock existingLock = lockMap.get(resourceId);
// No lock
if (existingLock == null)
{
// Try to create a new shared lock
if (mySharedLock == null)
{
mySharedLock = new SharedLock(this);
}
if (lockMap.putIfAbsent(resourceId, mySharedLock) == null)
{
// Success, we now hold the shared lock.
break;
}
else
{
continue;
}
}
// Someone holds shared lock on this entity, try and get in on that action
else if (existingLock is SharedLock)
{
if ((( SharedLock )existingLock).Acquire(this))
{
// Success!
break;
}
}
// Someone holds an exclusive lock on this entity
else if (existingLock is ExclusiveLock)
{
// We need to wait, just let the loop run.
}
else
{
throw new System.NotSupportedException("Unknown lock type: " + existingLock);
}
if (waitEvent == null)
{
waitEvent = tracer.WaitForLock(false, resourceType, resourceId);
}
// And take note of who we are waiting for. This is used for deadlock detection.
WaitFor(existingLock, resourceType, resourceId, false, tries++);
}
// Make a local note about the fact that we now hold this lock
heldShareLocks.put(resourceId, 1);
}
}
finally
{
if (waitEvent != null)
{
waitEvent.Close();
}
ClearWaitList();
_waitingForLock = null;
_stateHolder.decrementActiveClients();
}
}