protected override Task <MSBuildParseResult> StartParseAsync(
ITextSnapshot2 snapshot, MSBuildParseResult previousParse,
ITextSnapshot2 previousSnapshot, CancellationToken token)
{
if (runtimeInformation == null)
{
EnsureInitialized();
}
return(Task.Run(() => {
var oldDoc = previousParse?.MSBuildDocument;
var filepath = TryGetFilePath();
MSBuildRootDocument doc = MSBuildRootDocument.Empty;
try {
doc = MSBuildRootDocument.Parse(snapshot.GetTextSource(filepath), oldDoc, schemaProvider, runtimeInformation, taskMetadataBuilder, token);
} catch (Exception ex) {
LoggingService.LogError("Unhandled error in MSBuild parser", ex);
doc = MSBuildRootDocument.Empty;
}
return new MSBuildParseResult(doc, doc.XDocument, doc.Errors);
}));
}
ParseOperation CreateParseOperation(ITextSnapshot2 snapshot)
{
var tokenSource = new CancellationTokenSource();
var task = StartParseAsync(snapshot, tokenSource.Token);
var operation = new ParseOperation(this, task, snapshot, tokenSource);
#pragma warning disable VSTHRD110, VSTHRD105 // Observe result of async calls, Avoid method overloads that assume TaskScheduler.Current
//capture successful parses
task.ContinueWith((t, state) => {
var op = ((ParseOperation)state);
op.Parser.lastSuccessfulOperation = op;
try {
op.Parser.OnParseCompleted(op.Result, op.Snapshot);
} catch (Exception ex) {
op.Parser.OnUnhandledParseError(ex);
}
}, operation, TaskContinuationOptions.OnlyOnRanToCompletion | TaskContinuationOptions.ExecuteSynchronously);
//handle errors
task.ContinueWith((t, state) => {
var op = ((ParseOperation)state);
op.Parser.HandleUnhandledParseError(t.Exception);
}, operation, CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted, TaskScheduler.Default);
#pragma warning restore VSTHRD110, VSTHRD105
return(operation);
}
public ParseOperation(BackgroundParser <T> parser, Task <T> operation, ITextSnapshot2 snapshot, CancellationTokenSource tokenSource)
{
Parser = parser;
Task = operation;
Snapshot = snapshot;
this.tokenSource = tokenSource;
ownerCount = 1;
primaryOwnerCanceled = 0;
}
Task <T> StartParseAsync(ITextSnapshot2 snapshot, CancellationToken token)
{
var lastSuccessful = lastSuccessfulOperation;
if (lastSuccessful != null && lastSuccessful.Snapshot.Version.VersionNumber < snapshot.Version.VersionNumber)
{
return(StartParseAsync(snapshot, lastSuccessful.Result, lastSuccessful.Snapshot, token));
}
return(StartParseAsync(snapshot, default(T), null, token));
}
/// <summary>
/// Get an existing completed or running parse task for the provided snapshot if available, or creates a new parse task.
/// </summary>
public Task <T> GetOrParseAsync(ITextSnapshot2 snapshot, CancellationToken token)
{
var current = currentOperation;
if (current != null && current.Snapshot == snapshot && current.RegisterAdditionalCancellationOwner(token))
{
return(current.Task);
}
currentOperation = current = CreateParseOperation(snapshot);
return(current.Task);
}
public ParseCompletedEventArgs(T parseResult, ITextSnapshot2 snapshot)
{
ParseResult = parseResult;
Snapshot = snapshot;
}
protected abstract Task <T> StartParseAsync(ITextSnapshot2 snapshot, T previousParse, ITextSnapshot2 previousSnapshot, CancellationToken token);
protected virtual void OnParseCompleted(T parseResult, ITextSnapshot2 snapshot)
{
ParseCompleted?.Invoke(this, new ParseCompletedEventArgs <T> (parseResult, snapshot));
}
