/// <inheritdoc />
public Task <TValue> LoadAsync(TKey key)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
lock (_sync)
{
TKey resolvedKey = _cacheKeyResolver(key);
if (_options.Caching && _cache.TryGetValue(resolvedKey,
out Task <TValue> cachedValue))
{
DispatchingDiagnostics.RecordCachedValue(resolvedKey,
cachedValue);
return(cachedValue);
}
var promise = new TaskCompletionSource <TValue>(
TaskCreationOptions.RunContinuationsAsynchronously);
if (_options.Batching)
{
if (!_buffer.TryAdd(resolvedKey, promise) &&
_buffer.TryGetValue(resolvedKey,
out TaskCompletionSource <TValue> value))
{
promise.TrySetCanceled();
promise = value;
}
}
else
{
// note: must run in the background; do not await here.
Task.Factory.StartNew(
() => DispatchAsync(resolvedKey, promise),
TaskCreationOptions.RunContinuationsAsynchronously);
}
if (_options.Caching)
{
_cache.TryAdd(resolvedKey, promise.Task);
}
return(promise.Task);
}
}
/// <inheritdoc />
public Task <TValue> LoadAsync(
TKey key,
CancellationToken cancellationToken)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
lock (_sync)
{
object cacheKey = _cacheKeyResolver(key);
if (_options.Caching && _cache.TryGetValue(
cacheKey,
out Task <TValue>?cachedValue))
{
DiagnosticEvents.ReceivedValueFromCache(
key,
cacheKey,
cachedValue);
return(cachedValue);
}
var promise = new TaskCompletionSource <TValue>(
TaskCreationOptions.RunContinuationsAsynchronously);
if (_options.Batching)
{
if (!_buffer.TryAdd(key, promise) &&
_buffer.TryGetValue(
key,
out TaskCompletionSource <TValue>?value))
{
promise.TrySetCanceled();
promise = value;
}
else
{
RaiseRequestBuffered();
}
}
else
{
CancellationToken combinedToken = _disposeTokenSource
.CreateLinkedCancellationToken(cancellationToken);
// must run decoupled from this task, so that LoadAsync
// responds immediately; do not await here.
Task.Factory.StartNew(
() => DispatchSingleAsync(
key,
promise,
combinedToken),
TaskCreationOptions.RunContinuationsAsynchronously);
}
if (_options.Caching)
{
_cache.TryAdd(cacheKey, promise.Task);
}
return(promise.Task);
}
}