|
public static FutureIsReady ( |
||
| futureHandle | ||
| return | bool | |
internal FdbFutureArray(FutureHandle[] handles, Func <FutureHandle, T> selector, CancellationToken ct)
{
Contract.Requires(handles != null && selector != null);
m_handles = handles;
m_resultSelector = selector;
bool abortAllHandles = false;
try
{
if (ct.IsCancellationRequested)
{ // already cancelled, we must abort everything
SetFlag(FdbFuture.Flags.COMPLETED);
abortAllHandles = true;
m_resultSelector = null;
this.TrySetCanceled();
return;
}
// add this instance to the list of pending futures
var prm = RegisterCallback(this);
foreach (var handle in handles)
{
if (FdbNative.FutureIsReady(handle))
{ // this handle is already done
continue;
}
Interlocked.Increment(ref m_pending);
// register the callback handler
var err = FdbNative.FutureSetCallback(handle, CallbackHandler, prm);
if (Fdb.Failed(err))
{ // uhoh
Debug.WriteLine("Failed to set callback for Future<" + typeof(T).Name + "> 0x" + handle.Handle.ToString("x") + " !!!");
throw Fdb.MapToException(err) !;
}
}
// allow the callbacks to handle completion
TrySetFlag(FdbFuture.Flags.READY);
if (Volatile.Read(ref m_pending) == 0)
{ // all callbacks have already fired (or all handles were already completed)
UnregisterCallback(this);
HandleCompletion();
m_resultSelector = null;
abortAllHandles = true;
SetFlag(FdbFuture.Flags.COMPLETED);
}
else if (ct.CanBeCanceled)
{ // register for cancellation (if needed)
RegisterForCancellation(ct);
}
}
catch
{
// this is bad news, since we are in the constructor, we need to clear everything
SetFlag(FdbFuture.Flags.DISPOSED);
UnregisterCancellationRegistration();
UnregisterCallback(this);
abortAllHandles = true;
// this is technically not needed, but just to be safe...
this.TrySetCanceled();
throw;
}
finally
{
if (abortAllHandles)
{
CloseHandles(handles);
}
}
GC.KeepAlive(this);
}
internal FdbFutureSingle([NotNull] FutureHandle handle, [NotNull] Func <FutureHandle, T> selector, CancellationToken ct)
{
Contract.NotNull(handle, nameof(handle));
Contract.NotNull(selector, nameof(selector));
m_handle = handle;
m_resultSelector = selector;
try
{
if (handle.IsInvalid)
{ // it's dead, Jim !
SetFlag(FdbFuture.Flags.COMPLETED);
m_resultSelector = null;
return;
}
if (FdbNative.FutureIsReady(handle))
{ // either got a value or an error
#if DEBUG_FUTURES
Debug.WriteLine("Future<" + typeof(T).Name + "> 0x" + handle.Handle.ToString("x") + " was already ready");
#endif
HandleCompletion(fromCallback: false);
#if DEBUG_FUTURES
Debug.WriteLine("Future<" + typeof(T).Name + "> 0x" + handle.Handle.ToString("x") + " completed inline");
#endif
return;
}
// register for cancellation (if needed)
if (ct.CanBeCanceled)
{
if (ct.IsCancellationRequested)
{ // we have already been cancelled
#if DEBUG_FUTURES
Debug.WriteLine("Future<" + typeof(T).Name + "> 0x" + handle.Handle.ToString("x") + " will complete later");
#endif
// Abort the future and simulate a Canceled task
SetFlag(FdbFuture.Flags.COMPLETED);
// note: we don't need to call fdb_future_cancel because fdb_future_destroy will take care of everything
handle.Dispose();
// also, don't keep a reference on the callback because it won't be needed
m_resultSelector = null;
this.TrySetCanceled();
return;
}
// token still active
RegisterForCancellation(ct);
}
#if DEBUG_FUTURES
Debug.WriteLine("Future<" + typeof(T).Name + "> 0x" + handle.Handle.ToString("x") + " will complete later");
#endif
TrySetFlag(FdbFuture.Flags.READY);
// add this instance to the list of pending futures
var prm = RegisterCallback(this);
// register the callback handler
var err = FdbNative.FutureSetCallback(handle, CallbackHandler, prm);
if (Fdb.Failed(err))
{ // uhoh
#if DEBUG_FUTURES
Debug.WriteLine("Failed to set callback for Future<" + typeof(T).Name + "> 0x" + handle.Handle.ToString("x") + " !!!");
#endif
throw Fdb.MapToException(err);
}
}
catch
{
// this is bad news, since we are in the constructor, we need to clear everything
SetFlag(FdbFuture.Flags.DISPOSED);
UnregisterCancellationRegistration();
UnregisterCallback(this);
// kill the future handle
m_handle.Dispose();
// this is technically not needed, but just to be safe...
this.TrySetCanceled();
throw;
}
GC.KeepAlive(this);
}
