public async Task <RevalidationState> MaybeUpdateStateAsync(Func <RevalidationState, bool> updateAction)
{
var internalState = await GetInternalStateAsync();
var fileReference = internalState.FileReference;
var state = internalState.State;
// Only update the state if the update action returns true.
var originalState = new RevalidationState
{
IsInitialized = state.IsInitialized,
IsKillswitchActive = state.IsKillswitchActive,
DesiredPackageEventRate = state.DesiredPackageEventRate,
};
if (!updateAction(state))
{
return(originalState);
}
try
{
var accessCondition = AccessConditionWrapper.GenerateIfMatchCondition(fileReference.ContentId);
using (var stream = new MemoryStream())
using (var writer = new StreamWriter(stream))
using (var jsonWriter = new JsonTextWriter(writer))
{
_serializer.Serialize(jsonWriter, state);
jsonWriter.Flush();
stream.Position = 0;
await _storage.SaveFileAsync(CoreConstants.Folders.RevalidationFolderName, StateFileName, stream, accessCondition);
}
return(state);
}
catch (StorageException e) when(e.IsPreconditionFailedException())
{
throw new InvalidOperationException("Failed to update the state blob since the access condition failed", e);
}
}
public InternalState(IFileReference fileReference, RevalidationState state)
{
FileReference = fileReference ?? throw new ArgumentNullException(nameof(fileReference));
State = state ?? throw new ArgumentNullException(nameof(state));
}