internal async Task <long> AtomicIncDecAsync(string key, long amount, CancellationToken token = default)
{
long count = 0;
bool updated = false;
await ExecUtils.RetryUntilTrueAsync(async() =>
{
var entry = await GetEntryAsync(key, token);
if (entry == null)
{
count = amount;
entry = CreateTableEntry(key, Serialize(count));
try
{
updated = (await table.ExecuteAsync(TableOperation.Insert(entry), token)).HttpStatusCode == (int)HttpStatusCode.NoContent;
}
catch (StorageException ex)
{
if (!ex.HasStatus(HttpStatusCode.Conflict))
{
throw;
}
}
}
else
{
count = Deserialize <long>(entry.Data) + amount;
entry.Data = Serialize(count);
var op = TableOperation.Replace(entry);
try
{
var result = (await table.ExecuteAsync(op, null, null, token)).HttpStatusCode;
updated = result == (int)HttpStatusCode.OK || result == (int)HttpStatusCode.NoContent;
}
catch (StorageException ex)
{
if (!ex.HasStatus(HttpStatusCode.PreconditionFailed))
{
throw;
}
}
}
return(updated);
}, TimeSpan.FromSeconds(30));
return(count);
}
