internal static SnapshotLineRange GetLineRange(this ITextView textView, int startLine, int endLine = -1)
{
endLine = endLine >= 0 ? endLine : startLine;
return(SnapshotLineRange.CreateForLineNumberRange(textView.TextSnapshot, startLine, endLine).Value);
}
private static void GetTagsInBackgroundCore(
IAsyncTaggerSource <TData, TTag> asyncTaggerSource,
TData data,
int chunkCount,
Channel channel,
NormalizedLineRangeCollection visited,
CancellationToken cancellationToken,
Action <CompleteReason> onComplete,
Action <SnapshotLineRange, ReadOnlyCollection <ITagSpan <TTag> > > onProgress)
{
CompleteReason completeReason;
try
{
// Keep track of the LineRange values which we've already provided tags for. Don't
// duplicate the work
var toProcess = new Queue <SnapshotLineRange>();
// *** This value can be wrong ***
// This is the version number we expect the Channel to have. It's used
// as a hueristic to determine if we should prioritize a value off of the stack or our
// local stack. If it's wrong it means we prioritize the wrong value. Not a bug it
// just changes the order in which values will appear
var versionNumber = channel.CurrentVersion;
// Take one value off of the threadedLineRangeStack value. If the value is bigger than
// our chunking increment then we will add the value in chunks to the toProcess queue
Action popOne =
() =>
{
var value = channel.Read();
if (!value.HasValue)
{
return;
}
var lineRange = value.Value;
if (lineRange.Count <= chunkCount)
{
toProcess.Enqueue(lineRange);
return;
}
var snapshot = lineRange.Snapshot;
var startLineNumber = lineRange.StartLineNumber;
while (startLineNumber <= lineRange.LastLineNumber)
{
var startLine = snapshot.GetLineFromLineNumber(startLineNumber);
var localRange = SnapshotLineRange.CreateForLineAndMaxCount(startLine, chunkCount);
toProcess.Enqueue(localRange);
startLineNumber += chunkCount;
}
};
// Get the tags for the specified SnapshotLineRange and return the results. No chunking is done here,
// the data is just directly processed
Action <SnapshotLineRange> getTags =
tagLineRange =>
{
var unvisited = visited.GetUnvisited(tagLineRange.LineRange);
if (unvisited.HasValue)
{
var tagList = EmptyTagList;
try
{
tagLineRange = SnapshotLineRange.CreateForLineNumberRange(tagLineRange.Snapshot, unvisited.Value.StartLineNumber, unvisited.Value.LastLineNumber).Value;
tagList = asyncTaggerSource.GetTagsInBackground(data, tagLineRange.ExtentIncludingLineBreak, cancellationToken);
}
catch (Exception e)
{
// Ignore exceptions that are thrown by IAsyncTaggerSource. If the tagger threw then we consider
// the tags to be nothing for this span.
//
// It's important that we register some value here. If we register nothing then the foreground will
// never see this slot as fulfilled and later requests for this span will eventually queue up another
// background request
EditorUtilsTrace.TraceInfo("AsyncTagger source exception in background processing {0}", e);
}
visited.Add(tagLineRange.LineRange);
onProgress(tagLineRange, tagList);
}
};
do
{
versionNumber = channel.CurrentVersion;
popOne();
// We've drained both of the sources of input hence we are done
if (0 == toProcess.Count)
{
break;
}
while (0 != toProcess.Count)
{
// If at any point the threadLineRangeStack value changes we consider the new values to have
// priority over the old ones
if (versionNumber != channel.CurrentVersion)
{
break;
}
cancellationToken.ThrowIfCancellationRequested();
var lineRange = toProcess.Dequeue();
getTags(lineRange);
}
} while (!cancellationToken.IsCancellationRequested);
completeReason = cancellationToken.IsCancellationRequested
? CompleteReason.Cancelled
: CompleteReason.Finished;
}
catch (OperationCanceledException)
{
// Don't report cancellation exceptions. These are thrown during cancellation for fast
// break from the operation. It's really a control flow mechanism
completeReason = CompleteReason.Cancelled;
}
catch (Exception e)
{
// Handle cancellation exceptions and everything else. Don't want an errant
// exception thrown by the IAsyncTaggerSource to crash the process
EditorUtilsTrace.TraceInfo("AsyncTagger Exception in background processing {0}", e);
completeReason = CompleteReason.Error;
}
onComplete(completeReason);
}