public Task <MessageResult> GetMessages(IEnumerable <string> eventKeys, string id, CancellationToken cancellationToken)
{
TimeSpan timeout = TimeSpan.FromSeconds(55);
int maxMessages = 100;
// let's make sure we've got the message pump into the caches running
this.EnsureOpen();
var compositeCursor = new CompositeCursor(id, this.NumberOfTopics);
// grab what we can synchronously from the cache
var messages = this.FetchAvailableMessagesFromCache(compositeCursor, eventKeys, maxMessages);
if (messages.Count == 0)
{
// cache is drained for this client, so we'll have to wait for new messages
return(new TaskFactory <MessageResult>().FromAsync(
(cb, s) => this.BeginGetMessagesFromCache(eventKeys, compositeCursor, maxMessages, cancellationToken, cb, s),
this.EndGetMessagesFromCache, null));
}
// got a batch of messages, let's return it as a synchronous result
var r = new TaskCompletionSource <MessageResult>();
if (cancellationToken.IsCancellationRequested)
{
r.SetCanceled();
}
else
{
r.SetResult(new MessageResult(messages, compositeCursor.Cookie));
}
return(r.Task);
}
IList <Message> FetchAvailableMessagesFromCache(CompositeCursor compositeCursor, IEnumerable <string> eventKeys, int maxMessages)
{
var messages = new List <Message>();
bool gotAny;
do
{
gotAny = false;
for (var i = 0; i < this.NumberOfTopics; i++)
{
if (compositeCursor.CursorInitFlags[i])
{
var hwmi = compositeCursor.Cursors[i];
Message msg;
if (this.caches[i].TryGetNext(eventKeys, ref hwmi, out msg))
{
gotAny = true;
messages.Add(msg);
compositeCursor.Cursors[i] = hwmi;
if (messages.Count >= maxMessages)
{
// have enough?
// cheat to get out of the outer loop
gotAny = false;
// and GTFO
break;
}
}
else
{
// try does advance the cursor
compositeCursor.Cursors[i] = hwmi;
}
}
else
{
ushort cursor;
if (caches[i].TryGetTopOfSequenceCursor(out cursor))
{
compositeCursor.CursorInitFlags[i] = true;
compositeCursor.Cursors[i] = cursor;
}
}
}
}while (gotAny);
messages.Sort((m1, m2) => m1.Created.CompareTo(m2.Created));
return(messages);
}
public GetMessagesFromCacheAsyncResult(
ServiceBusMessageBus that,
IEnumerable <string> keys,
CompositeCursor compositeCursor,
int maxMessages,
CancellationToken cancellationToken,
AsyncCallback callback,
object state)
: base(callback, state)
{
this.that = that;
this.keys = keys;
this.compositeCursor = compositeCursor;
this.maxMessages = maxMessages;
this.cancellationToken = cancellationToken;
this.mad = new MessageAvailableDispatcher(this.MessageAvailable, that.caches, keys, cancellationToken);
this.cancellationToken.Register(Cancel);
}
public Task<MessageResult> GetMessages(IEnumerable<string> eventKeys, string id, CancellationToken cancellationToken)
{
TimeSpan timeout = TimeSpan.FromSeconds(55);
int maxMessages = 100;
// let's make sure we've got the message pump into the caches running
this.EnsureOpen();
var compositeCursor = new CompositeCursor(id, this.NumberOfTopics);
// grab what we can synchronously from the cache
var messages = this.FetchAvailableMessagesFromCache(compositeCursor, eventKeys, maxMessages);
if (messages.Count == 0)
{
// cache is drained for this client, so we'll have to wait for new messages
return new TaskFactory<MessageResult>().FromAsync(
(cb, s) => this.BeginGetMessagesFromCache(eventKeys, compositeCursor, maxMessages, cancellationToken, cb, s),
this.EndGetMessagesFromCache, null);
}
// got a batch of messages, let's return it as a synchronous result
var r = new TaskCompletionSource<MessageResult>();
if (cancellationToken.IsCancellationRequested)
{
r.SetCanceled();
}
else
{
r.SetResult(new MessageResult(messages, compositeCursor.Cookie));
}
return r.Task;
}
IAsyncResult BeginGetMessagesFromCache(IEnumerable<string> eventKeys, CompositeCursor id, int maxMessages, CancellationToken cancellationToken, AsyncCallback callback, object state)
{
return new GetMessagesFromCacheAsyncResult(this, eventKeys, id, maxMessages, cancellationToken, callback, state);
}
IList<Message> FetchAvailableMessagesFromCache(CompositeCursor compositeCursor, IEnumerable<string> eventKeys, int maxMessages)
{
var messages = new List<Message>();
bool gotAny;
do
{
gotAny = false;
for (var i = 0; i < this.NumberOfTopics; i++)
{
if (compositeCursor.CursorInitFlags[i])
{
var hwmi = compositeCursor.Cursors[i];
Message msg;
if (this.caches[i].TryGetNext(eventKeys, ref hwmi, out msg))
{
gotAny = true;
messages.Add(msg);
compositeCursor.Cursors[i] = hwmi;
if (messages.Count >= maxMessages)
{
// have enough?
// cheat to get out of the outer loop
gotAny = false;
// and GTFO
break;
}
}
else
{
// try does advance the cursor
compositeCursor.Cursors[i] = hwmi;
}
}
else
{
ushort cursor;
if (caches[i].TryGetTopOfSequenceCursor(out cursor))
{
compositeCursor.CursorInitFlags[i] = true;
compositeCursor.Cursors[i] = cursor;
}
}
}
}
while (gotAny);
messages.Sort((m1, m2) => m1.Created.CompareTo(m2.Created));
return messages;
}
IAsyncResult BeginGetMessagesFromCache(IEnumerable <string> eventKeys, CompositeCursor id, int maxMessages, CancellationToken cancellationToken, AsyncCallback callback, object state)
{
return(new GetMessagesFromCacheAsyncResult(this, eventKeys, id, maxMessages, cancellationToken, callback, state));
}
