// Protected methods
protected static void SetReturnValue(ComputeMethodInput input, Result <TOut> output)
{
if (input.Method.ReturnsValueTask)
{
input.Invocation.ReturnValue =
// ReSharper disable once HeapView.BoxingAllocation
output.IsValue(out var v)
? ValueTaskEx.FromResult(v)
: ValueTaskEx.FromException <TOut>(output.Error !);
}
else
{
input.Invocation.ReturnValue =
output.IsValue(out var v)
? Task.FromResult(v)
: Task.FromException <TOut>(output.Error !);
}
}
public override async Task <T> InvokeAndStrip(
ComputeMethodInput input, IComputed?usedBy, ComputeContext?context,
CancellationToken cancellationToken = default)
{
context ??= ComputeContext.Current;
ResultBox <T>?output;
// Read-Lock-RetryRead-Compute-Store pattern
var computed = TryGetExisting(input);
if (computed != null)
{
output = await computed.TryUseExisting(context, usedBy, cancellationToken)
.ConfigureAwait(false);
if (output != null)
{
return(output.Value);
}
}
using var @lock = await Locks.Lock(input, cancellationToken).ConfigureAwait(false);
computed = TryGetExisting(input);
if (computed != null)
{
output = await computed.TryUseExisting(context, usedBy, cancellationToken)
.ConfigureAwait(false);
if (output != null)
{
return(output.Value);
}
}
computed = (IAsyncComputed <T>) await Compute(input, computed, cancellationToken)
.ConfigureAwait(false);
var rOutput = computed.Output; // RenewTimeouts isn't called yet, so it's ok
computed.UseNew(context, usedBy);
return(rOutput !.Value);
}
protected override async ValueTask <IComputed <T> > Compute(
ComputeMethodInput input, IComputed <T>?existing,
CancellationToken cancellationToken)
{
var tag = VersionGenerator.Next();
var computed = CreateComputed(input, tag);
try {
using var _ = Computed.ChangeCurrent(computed);
var result = input.InvokeOriginalFunction(cancellationToken);
if (input.Method.ReturnsValueTask)
{
var output = await((ValueTask <T>)result).ConfigureAwait(false);
computed.TrySetOutput(output);
}
else
{
var output = await((Task <T>)result).ConfigureAwait(false);
computed.TrySetOutput(output);
}
}
catch (OperationCanceledException e) {
computed.TrySetOutput(Result.Error <T>(e));
computed.Invalidate();
throw;
}
catch (Exception e) {
if (e is AggregateException ae)
{
e = ae.GetFirstInnerException();
}
computed.TrySetOutput(Result.Error <T>(e));
// Weird case: if the output is already set, all we can
// is to ignore the exception we've just caught;
// throwing it further will probably make it just worse,
// since the the caller have to take this scenario into acc.
}
return(computed);
}
protected abstract IComputed <T> CreateComputed(ComputeMethodInput input, LTag tag);
protected new IAsyncComputed <T>?TryGetExisting(ComputeMethodInput input)
{
var computed = ComputedRegistry.Instance.TryGet(input);
return(computed as IAsyncComputed <T>);
}
protected override IComputed <T> CreateComputed(ComputeMethodInput input, LTag tag) => new SwappingComputed <T>(Options, input, tag);