/// <summary>
/// Erzeugt eine neue Hintergrundaufgabe.
/// </summary>
/// <param name="worker">Der Algorithmus zur Ausführung.</param>
/// <returns>Die neue Aufgabe.</returns>
public static CancellableTask <TResultType> Run(Func <CancellationToken, TResultType> worker)
{
// Validate
if (worker == null)
{
throw new ArgumentException("no task worker provided", "worker");
}
// Allow self reference to new instance
CancellableTask <TResultType> task = null;
// Create instance
task =
new CancellableTask <TResultType>(() =>
{
// Provide cleanup of cancel source
using (var controller = task.m_cancel)
try
{
// Try to process without generating exception - if possible
return(worker(controller.Token));
}
catch (Exception)
{
// In case of any error just report nothing - not applyable to value types
return(null);
}
finally
{
// Never use cancel source again
task.m_cancel = null;
}
});
// Make sure we clean up in case we are not able to start the task
try
{
// Request start
task.Start();
}
catch (Exception)
{
// Forward with cleanup
using (task.m_cancel)
throw;
}
// Report
return(task);
}
/// <summary>
/// Initialisiert eine Hintergrundaufgabe.
/// </summary>
/// <typeparam name="TResultType">Die Art des Ergebnisses der Aufgabe.</typeparam>
/// <param name="reader">Die aktuelle Hintergrundaufgabe.</param>
/// <param name="factory">Optional die Methode zur Neuinitialisierung.</param>
/// <returns>Die neue Hintergrundaufgabe.</returns>
private CancellableTask <TResultType> ResetReader <TResultType>(ref CancellableTask <TResultType> reader, Func <CancellableTask <TResultType> > factory = null) where TResultType : class
{
// Wipe out
var previous = Interlocked.Exchange(ref reader, null);
// Stop it
if (previous != null)
{
previous.Cancel();
}
// New one
if (factory != null)
{
reader = factory();
}
// Report
return(reader);
}
/// <summary>
/// Beginnt mit dem Auslesen der Quelldaten.
/// </summary>
/// <param name="source">Die gewünschte Quelle.</param>
/// <param name="device">Das zu verwendende Gerät.</param>
/// <param name="profile">Optional das zu berücksichtigende Geräteprofil.</param>
/// <returns>Die Hintergrundaufgabe zum Auslesen der Quelledaten.</returns>
public static CancellableTask <SourceInformation> GetSourceInformationAsync(this Hardware device, SourceIdentifier source, Profile profile = null)
{
// Validate
if (device == null)
{
throw new ArgumentNullException("no hardware to use", "device");
}
if (source == null)
{
throw new ArgumentException("no source to get information for", "source");
}
// Attach to tasks
var patReader = device.AssociationTableReader;
var groupReader = device.GroupReader;
// Start
return
(CancellableTask <SourceInformation> .Run(cancel =>
{
// Check tasks
if (groupReader == null)
{
return null;
}
if (patReader == null)
{
return null;
}
// Wait on tasks
if (!groupReader.CancellableWait(cancel))
{
return null;
}
if (!patReader.CancellableWait(cancel))
{
return null;
}
// Get the current group information
var groupInfo = groupReader.Result;
if (groupInfo == null)
{
return null;
}
// See if group exists
if (!groupInfo.Sources.Any(source.Equals))
{
return null;
}
// Find the stream identifier for the service
var pmtIdentifier = patReader.Result.FindService(source.Service);
if (!pmtIdentifier.HasValue)
{
return null;
}
// Wait for mapping table
var pmtReader = device.GetTableAsync <PMT>(pmtIdentifier.Value);
if (!pmtReader.CancellableWait(cancel))
{
return null;
}
// Request table
var pmts = pmtReader.Result;
if (pmts == null)
{
return null;
}
// Create dummy
var currentSettings = new SourceInformation {
Source = source, VideoType = VideoTypes.NoVideo
};
// Process all PMT - actually should be only one
foreach (var pmt in pmts)
{
// Overwrite encryption if CA descriptor is present
if (pmt.Table.Descriptors != null)
{
currentSettings.IsEncrypted = pmt.Table.Descriptors.Any(descriptor => EPG.DescriptorTags.CA == descriptor.Tag);
}
// Process the program entries
foreach (var program in pmt.Table.ProgramEntries)
{
currentSettings.Update(program);
}
}
// Find the related station information
var station = groupInfo.Sources.FirstOrDefault(source.Equals) as Station;
if (station != null)
{
// Take data from there
currentSettings.Provider = station.Provider;
currentSettings.Name = station.Name;
// See if this is a service
currentSettings.IsService = station.IsService;
// Overwrite encryption if regular service entry exists
if (!currentSettings.IsService)
{
currentSettings.IsEncrypted = station.IsEncrypted;
}
}
// See if profile is attached
if (profile != null)
{
// Apply the modifier
var modifier = profile.GetFilter(currentSettings.Source);
if (modifier != null)
{
modifier.ApplyTo(currentSettings);
}
}
// Report
return currentSettings;
}));
}
/// <summary>
/// Erzeugt eine neue Hintergrundaufgabe zum Auslesen von SI Tabellen.
/// </summary>
/// <param name="device">Das zu verwendende Gerät.</param>
/// <param name="stream">Die Datenstromkennung, die überwacht werden soll.</param>
/// <returns>Die neue Aufgabe.</returns>
public static CancellableTask <TTableType[]> GetTableAsync <TTableType>(this Hardware device, ushort stream) where TTableType : Table
{
// Validate
if (device == null)
{
throw new ArgumentException("no hardware to use", "device");
}
// Create the task
return
(CancellableTask <TTableType[]> .Run(cancel =>
{
// Termination synchronisation
var sync = new object();
var done = false;
// Parsing state
var tables = default(TTableType[]);
var expectedVersion = 0;
var collectedParts = 0;
// Create parser
var parser = TableParser.Create(( TTableType table ) =>
{
// Disabled
if (done)
{
return;
}
// Check version
if (tables != null)
{
if (table.Version != expectedVersion)
{
tables = null;
}
}
// Discard on count mismatch
if (tables != null)
{
if (tables.Length != (table.LastSection + 1))
{
tables = null;
}
}
// Discard on overrun
if (tables != null)
{
if (table.CurrentSection >= tables.Length)
{
tables = null;
}
}
// Discard on duplicates
if (tables != null)
{
if (tables[table.CurrentSection] != null)
{
tables = null;
}
}
// Create once
if (tables == null)
{
// Create in full size
tables = new TTableType[table.LastSection + 1];
expectedVersion = table.Version;
collectedParts = 0;
}
// Add it
tables[table.CurrentSection] = table;
// Mark as done
if (++collectedParts >= tables.Length)
{
lock (sync)
{
done = true;
// Our wake up call
Monitor.Pulse(sync);
}
}
});
// Register with cleanup
var tableType = Table.GetIsExtendedTable <TTableType>() ? StreamTypes.ExtendedTable : StreamTypes.StandardTable;
var registration = device.AddConsumer(stream, tableType, parser.AddPayload);
try
{
// Start receiving data
device.SetConsumerState(registration, true);
// Wait for end and fully process the cancellation token
using (cancel.Register(() => { lock (sync) Monitor.Pulse(sync); }))
lock (sync)
while (!done)
{
if (cancel.IsCancellationRequested)
{
return null;
}
else
{
Monitor.Wait(sync);
}
}
}
finally
{
// Cleanup
device.SetConsumerState(registration, null);
}
// Report
return tables;
}));
}
