/// <summary>
/// Receive a message from the language server.
/// </summary>
/// <returns>
/// A <see cref="ServerMessage"/> representing the message,
/// </returns>
async Task <ServerMessage> ReceiveMessage()
{
Log.LogDebug("Reading response headers...");
byte[] headerBuffer = new byte[HeaderBufferSize];
int bytesRead = await _input.ReadAsync(headerBuffer, 0, MinimumHeaderLength, _cancellation);
Log.LogDebug("Read {ByteCount} bytes from input stream.", bytesRead);
if (bytesRead == 0)
{
return(null); // Stream closed.
}
const byte CR = (byte)'\r';
const byte LF = (byte)'\n';
while (bytesRead < MinimumHeaderLength ||
headerBuffer[bytesRead - 4] != CR || headerBuffer[bytesRead - 3] != LF ||
headerBuffer[bytesRead - 2] != CR || headerBuffer[bytesRead - 1] != LF)
{
Log.LogDebug("Reading additional data from input stream...");
// Read single bytes until we've got a valid end-of-header sequence.
var additionalBytesRead = await _input.ReadAsync(headerBuffer, bytesRead, 1, _cancellation);
if (additionalBytesRead == 0)
{
return(null); // no more _input, mitigates endless loop here.
}
Log.LogDebug("Read {ByteCount} bytes of additional data from input stream.", additionalBytesRead);
bytesRead += additionalBytesRead;
}
string headers = HeaderEncoding.GetString(headerBuffer, 0, bytesRead);
Log.LogDebug("Got raw headers: {Headers}", headers);
if (String.IsNullOrWhiteSpace(headers))
{
return(null); // Stream closed.
}
Log.LogDebug("Read response headers {Headers}.", headers);
Dictionary <string, string> parsedHeaders = ParseHeaders(headers);
string contentLengthHeader;
if (!parsedHeaders.TryGetValue("Content-Length", out contentLengthHeader))
{
Log.LogDebug("Invalid request headers (missing 'Content-Length' header).");
return(null);
}
int contentLength = Int32.Parse(contentLengthHeader);
Log.LogDebug("Reading response body ({ExpectedByteCount} bytes expected).", contentLength);
var requestBuffer = new byte[contentLength];
var received = 0;
while (received < contentLength)
{
Log.LogDebug("Reading segment of incoming request body ({ReceivedByteCount} of {TotalByteCount} bytes so far)...", received, contentLength);
var payloadBytesRead = await _input.ReadAsync(requestBuffer, received, requestBuffer.Length - received, _cancellation);
if (payloadBytesRead == 0)
{
Log.LogWarning("Bailing out of reading payload (no_more_input after {ByteCount} bytes)...", received);
return(null);
}
received += payloadBytesRead;
Log.LogDebug("Read segment of incoming request body ({ReceivedByteCount} of {TotalByteCount} bytes so far).", received, contentLength);
}
Log.LogDebug("Received entire payload ({ReceivedByteCount} bytes).", received);
string responseBody = PayloadEncoding.GetString(requestBuffer);
ServerMessage message = JsonConvert.DeserializeObject <ServerMessage>(responseBody);
Log.LogDebug("Read response body {ResponseBody}.", responseBody);
return(message);
}
/// <summary>
/// Dispatch a request.
/// </summary>
/// <param name="requestMessage">
/// The request message.
/// </param>
private void DispatchRequest(ServerMessage requestMessage)
{
if (requestMessage == null)
{
throw new ArgumentNullException(nameof(requestMessage));
}
string requestId = requestMessage.Id.ToString();
Log.LogDebug("Dispatching incoming {RequestMethod} request {RequestId}...", requestMessage.Method, requestId);
CancellationTokenSource requestCancellation = CancellationTokenSource.CreateLinkedTokenSource(_cancellation);
_requestCancellations.TryAdd(requestId, requestCancellation);
Task <object> handlerTask = _dispatcher.TryHandleRequest(requestMessage.Method, requestMessage.Params, requestCancellation.Token);
if (handlerTask == null)
{
Log.LogWarning("Unable to dispatch incoming {RequestMethod} request {RequestId} (no handler registered).", requestMessage.Method, requestId);
_outgoing.TryAdd(
new JsonRpcMessages.MethodNotFound(requestMessage.Id, requestMessage.Method)
);
return;
}
#pragma warning disable CS4014 // Continuation does the work we need; no need to await it as this would tie up the dispatch loop.
handlerTask.ContinueWith(_ =>
{
if (handlerTask.IsCanceled)
{
Log.LogDebug("{RequestMethod} request {RequestId} canceled.", requestMessage.Method, requestId);
}
else if (handlerTask.IsFaulted)
{
Exception handlerError = handlerTask.Exception.Flatten().InnerExceptions[0];
Log.LogError(handlerError, "{RequestMethod} request {RequestId} failed (unexpected error raised by handler).", requestMessage.Method, requestId);
_outgoing.TryAdd(new RpcError(requestId,
new JsonRpcMessages.ErrorMessage(
code: 500,
message: "Error processing request: " + handlerError.Message,
data: handlerError.ToString()
)
));
}
else if (handlerTask.IsCompleted)
{
Log.LogDebug("{RequestMethod} request {RequestId} complete (Result = {@Result}).", requestMessage.Method, requestId, handlerTask.Result);
_outgoing.TryAdd(new ClientMessage
{
Id = requestMessage.Id,
Method = requestMessage.Method,
Result = handlerTask.Result != null ? JObject.FromObject(handlerTask.Result) : null
});
}
_requestCancellations.TryRemove(requestId, out CancellationTokenSource cancellation);
cancellation.Dispose();
});
#pragma warning restore CS4014 // Continuation does the work we need; no need to await it as this would tie up the dispatch loop.
Log.LogDebug("Dispatched incoming {RequestMethod} request {RequestId}.", requestMessage.Method, requestMessage.Id);
}
/// <summary>
/// The connection's message-receive loop.
/// </summary>
/// <returns>
/// A <see cref="Task"/> representing the loop's activity.
/// </returns>
async Task ReceiveLoop()
{
await Task.Yield();
Log.LogInformation("Receive loop started.");
try
{
while (!_cancellation.IsCancellationRequested && !_incoming.IsAddingCompleted)
{
ServerMessage message = await ReceiveMessage();
if (message == null)
{
continue;
}
_cancellation.ThrowIfCancellationRequested();
try
{
if (message.Id != null)
{
// Request or response.
if (message.Params != null)
{
// Request.
Log.LogDebug("Received {RequestMethod} request {RequestId} from language server: {RequestParameters}",
message.Method,
message.Id,
message.Params?.ToString(Formatting.None)
);
// Publish.
if (!_incoming.IsAddingCompleted)
{
_incoming.TryAdd(message);
}
}
else
{
// Response.
string requestId = message.Id.ToString();
TaskCompletionSource <ServerMessage> completion;
if (_responseCompletions.TryGetValue(requestId, out completion))
{
if (message.Error != null)
{
Log.LogDebug("Received error response {RequestId} from language server: {@ErrorMessage}",
requestId,
message.Error
);
Log.LogDebug("Faulting request {RequestId}.", requestId);
completion.TrySetException(
CreateLspException(message)
);
}
else
{
Log.LogDebug("Received response {RequestId} from language server: {ResponseResult}",
requestId,
message.Result?.ToString(Formatting.None)
);
Log.LogDebug("Completing request {RequestId}.", requestId);
completion.TrySetResult(message);
}
}
else
{
Log.LogDebug("Received unexpected response {RequestId} from language server: {ResponseResult}",
requestId,
message.Result?.ToString(Formatting.None)
);
}
}
}
else
{
// Notification.
Log.LogDebug("Received {NotificationMethod} notification from language server: {NotificationParameters}",
message.Method,
message.Params?.ToString(Formatting.None)
);
// Publish.
if (!_incoming.IsAddingCompleted)
{
_incoming.TryAdd(message);
}
}
}
catch (Exception dispatchError)
{
Log.LogError(dispatchError, "Unexpected error processing incoming message {@Message}.", message);
}
}
}
catch (OperationCanceledException operationCanceled)
{
// Like tears in rain
if (operationCanceled.CancellationToken != _cancellation)
{
throw; // time to die
}
}
finally
{
Log.LogInformation("Receive loop terminated.");
}
}