private static IEnumerable <AsyncResultOr <string> > ProcessRequest(ElmahCore.ErrorLog log, HttpContext context, Func <AsyncCallback> getAsyncCallback, Format format, int maxDownloadCount)
{
var response = context.Response;
foreach (var text in format.Header())
{
yield return(AsyncResultOr.Value(text));
}
var lastBeatTime = DateTime.Now;
var errorEntryList = new List <ErrorLogEntry>(PageSize);
var downloadCount = 0;
for (var pageIndex = 0; ; pageIndex++)
{
var ar = log.BeginGetErrors(pageIndex, PageSize, errorEntryList,
getAsyncCallback(), null);
yield return(AsyncResultOr.InsteadOf <string>(ar));
var total = log.EndGetErrors(ar);
var count = errorEntryList.Count;
if (maxDownloadCount > 0)
{
var remaining = maxDownloadCount - (downloadCount + count);
if (remaining < 0)
{
count += remaining;
}
}
foreach (var entry in format.Entries(errorEntryList, 0, count, total))
{
yield return(AsyncResultOr.Value(entry));
}
downloadCount += count;
response.Body.Flush();
//
// Done if either the end of the list (no more errors found) or
// the requested limit has been reached.
//
if (count == 0 || downloadCount == maxDownloadCount)
{
if (count > 0)
{
foreach (var entry in format.Entries(new ErrorLogEntry[0], total)) // Terminator
{
yield return(AsyncResultOr.Value(entry));
}
}
break;
}
//
// Poll whether the client is still connected so data is not
// unnecessarily sent to an abandoned connection. This check is
// only performed at certain intervals.
//
if (DateTime.Now - lastBeatTime > BeatPollInterval)
{
lastBeatTime = DateTime.Now;
}
//
// Fetch next page of results.
//
errorEntryList.Clear();
}
}
