// Can't throw.
private void wakeConnectionWaitersLocked() {
// Unpark all waiters that have requests that we can fulfill.
// This method is designed to not throw runtime exceptions, although we might send
// a waiter an exception for it to rethrow.
ConnectionWaiter predecessor = null;
ConnectionWaiter waiter = mConnectionWaiterQueue;
boolean primaryConnectionNotAvailable = false;
boolean nonPrimaryConnectionNotAvailable = false;
while (waiter != null) {
boolean unpark = false;
if (!mIsOpen) {
unpark = true;
} else {
try {
SQLiteConnection connection = null;
if (!waiter.mWantPrimaryConnection && !nonPrimaryConnectionNotAvailable) {
connection =
tryAcquireNonPrimaryConnectionLocked(
waiter.mSql, waiter.mConnectionFlags); // might throw
if (connection == null) {
nonPrimaryConnectionNotAvailable = true;
}
}
if (connection == null && !primaryConnectionNotAvailable) {
connection = tryAcquirePrimaryConnectionLocked(waiter.mConnectionFlags); // might throw
if (connection == null) {
primaryConnectionNotAvailable = true;
}
}
if (connection != null) {
waiter.mAssignedConnection = connection;
unpark = true;
} else if (nonPrimaryConnectionNotAvailable && primaryConnectionNotAvailable) {
// There are no connections available and the pool is still open.
// We cannot fulfill any more connection requests, so stop here.
break;
}
} catch (RuntimeException ex) {
// Let the waiter handle the exception from acquiring a connection.
waiter.mException = ex;
unpark = true;
}
}
final ConnectionWaiter successor = waiter.mNext;
if (unpark) {
if (predecessor != null) {
predecessor.mNext = successor;
} else {
mConnectionWaiterQueue = successor;
}
waiter.mNext = null;
LockSupport.unpark(waiter.mThread);
} else {
predecessor = waiter;
}
waiter = successor;
}
}
// Can't throw.
private void cancelConnectionWaiterLocked(ConnectionWaiter waiter) {
if (waiter.mAssignedConnection != null || waiter.mException != null) {
// Waiter is done waiting but has not woken up yet.
return;
}
// Waiter must still be waiting. Dequeue it.
ConnectionWaiter predecessor = null;
ConnectionWaiter current = mConnectionWaiterQueue;
while (current != waiter) {
assert current != null;
predecessor = current;
current = current.mNext;
}
if (predecessor != null) {
predecessor.mNext = waiter.mNext;
} else {
mConnectionWaiterQueue = waiter.mNext;
}
// Send the waiter an exception and unpark it.
waiter.mException = new OperationCanceledException();
LockSupport.unpark(waiter.mThread);
// Check whether removing this waiter will enable other waiters to make progress.
wakeConnectionWaitersLocked();
}
private void recycleConnectionWaiterLocked(ConnectionWaiter waiter) {
waiter.mNext = mConnectionWaiterPool;
waiter.mThread = null;
waiter.mSql = null;
waiter.mAssignedConnection = null;
waiter.mException = null;
waiter.mNonce += 1;
mConnectionWaiterPool = waiter;
}