public static async Task <IComputed <T> > CaptureAsync <T>(Func <CancellationToken, Task <T> > producer, CancellationToken cancellationToken = default)
{
using var ccs = ComputeContext.New(CallOptions.Capture).Activate();
IComputed <T>?result;
try {
await producer.Invoke(cancellationToken).ConfigureAwait(false);
}
catch (OperationCanceledException) {
throw;
}
catch (Exception) {
result = ccs.Context.GetCapturedComputed <T>();
if (result?.Error != null)
{
return(result);
}
throw;
}
result = ccs.Context.GetCapturedComputed <T>();
if (result == null)
{
throw Errors.NoComputedCaptured();
}
return(result);
}
public static IComputed <T>?TryGetExisting <T>(Func <ValueTask <T> > producer)
{
using var ccs = ComputeContext.New(CallOptions.TryGetExisting | CallOptions.Capture).Activate();
var task = producer.Invoke();
task.AssertCompleted(); // The must be always synchronous in this case
return(ccs.Context.GetCapturedComputed <T>());
}
public static void Invalidate <T>(Func <ValueTask <T> > producer)
{
using var ccs = ComputeContext.New(CallOptions.Invalidate).Activate();
var task = producer.Invoke();
// The flow is essentially synchronous in this case, so...
task.AssertCompleted();
}
internal ComputeContextScope(ComputeContext context)
{
var current = ComputeContext.CurrentLocal;
_previousContext = current.Value;
current.Value = context;
Context = context;
}
// TryGetExisting
public static IComputed <T>?TryGetExisting <T>(Func <Task <T> > producer)
{
using var ccs = ComputeContext.New(CallOptions.TryGetExisting | CallOptions.Capture).Activate();
var task = producer.Invoke();
// The flow is essentially synchronous in this case, so...
task.AssertCompleted();
return(ccs.Context.GetCapturedComputed <T>());
}
internal ComputeContextScope(ComputeContext context)
{
_oldContext = ComputeContext.Current;
Context = context;
if (_oldContext != context)
{
ComputeContext.Current = context;
}
}
// Capture & invalidate
public static async Task <IComputed <T>?> TryCaptureAsync <T>(Func <CancellationToken, Task <T> > producer, CancellationToken cancellationToken = default)
{
using var ccs = ComputeContext.New(CallOptions.Capture).Activate();
await producer.Invoke(cancellationToken).ConfigureAwait(false);
var result = ccs.Context.GetCapturedComputed <T>();
return(result);
}
static ComputeContext()
{
var allCallOptions = CallOptions.TryGetCached | CallOptions.Invalidate;
var cache = new Dictionary <CallOptions, ComputeContext>();
for (var i = 0; i <= (int)allCallOptions; i++)
{
var action = (CallOptions)i;
cache[action] = new CachedComputeContext(action);
}
ContextCache = cache;
Default = New(default);
internal ComputeContextScope(ComputeContext context)
{
Context = context;
_previousContext = ComputeContext.Current;
ComputeContext.Current = context;
}
