1 //===------- RPCUTils.h - Utilities for building RPC APIs -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Utilities to support construction of simple RPC APIs.
12 // The RPC utilities aim for ease of use (minimal conceptual overhead) for C++
13 // programmers, high performance, low memory overhead, and efficient use of the
14 // communications channel.
16 //===----------------------------------------------------------------------===//
18 #ifndef LLVM_EXECUTIONENGINE_ORC_RPCUTILS_H
19 #define LLVM_EXECUTIONENGINE_ORC_RPCUTILS_H
25 #include "llvm/ADT/STLExtras.h"
26 #include "llvm/ExecutionEngine/Orc/OrcError.h"
27 #include "llvm/ExecutionEngine/Orc/RPCSerialization.h"
28 #include "llvm/Support/MSVCErrorWorkarounds.h"
36 /// Base class of all fatal RPC errors (those that necessarily result in the
37 /// termination of the RPC session).
38 class RPCFatalError : public ErrorInfo<RPCFatalError> {
43 /// RPCConnectionClosed is returned from RPC operations if the RPC connection
44 /// has already been closed due to either an error or graceful disconnection.
45 class ConnectionClosed : public ErrorInfo<ConnectionClosed> {
48 std::error_code convertToErrorCode() const override;
49 void log(raw_ostream &OS) const override;
52 /// BadFunctionCall is returned from handleOne when the remote makes a call with
53 /// an unrecognized function id.
55 /// This error is fatal because Orc RPC needs to know how to parse a function
56 /// call to know where the next call starts, and if it doesn't recognize the
57 /// function id it cannot parse the call.
58 template <typename FnIdT, typename SeqNoT>
60 : public ErrorInfo<BadFunctionCall<FnIdT, SeqNoT>, RPCFatalError> {
64 BadFunctionCall(FnIdT FnId, SeqNoT SeqNo)
65 : FnId(std::move(FnId)), SeqNo(std::move(SeqNo)) {}
67 std::error_code convertToErrorCode() const override {
68 return orcError(OrcErrorCode::UnexpectedRPCCall);
71 void log(raw_ostream &OS) const override {
72 OS << "Call to invalid RPC function id '" << FnId << "' with "
73 "sequence number " << SeqNo;
81 template <typename FnIdT, typename SeqNoT>
82 char BadFunctionCall<FnIdT, SeqNoT>::ID = 0;
84 /// InvalidSequenceNumberForResponse is returned from handleOne when a response
85 /// call arrives with a sequence number that doesn't correspond to any in-flight
88 /// This error is fatal because Orc RPC needs to know how to parse the rest of
89 /// the response call to know where the next call starts, and if it doesn't have
90 /// a result parser for this sequence number it can't do that.
91 template <typename SeqNoT>
92 class InvalidSequenceNumberForResponse
93 : public ErrorInfo<InvalidSequenceNumberForResponse<SeqNoT>, RPCFatalError> {
97 InvalidSequenceNumberForResponse(SeqNoT SeqNo)
98 : SeqNo(std::move(SeqNo)) {}
100 std::error_code convertToErrorCode() const override {
101 return orcError(OrcErrorCode::UnexpectedRPCCall);
104 void log(raw_ostream &OS) const override {
105 OS << "Response has unknown sequence number " << SeqNo;
111 template <typename SeqNoT>
112 char InvalidSequenceNumberForResponse<SeqNoT>::ID = 0;
114 /// This non-fatal error will be passed to asynchronous result handlers in place
115 /// of a result if the connection goes down before a result returns, or if the
116 /// function to be called cannot be negotiated with the remote.
117 class ResponseAbandoned : public ErrorInfo<ResponseAbandoned> {
121 std::error_code convertToErrorCode() const override;
122 void log(raw_ostream &OS) const override;
125 /// This error is returned if the remote does not have a handler installed for
126 /// the given RPC function.
127 class CouldNotNegotiate : public ErrorInfo<CouldNotNegotiate> {
131 CouldNotNegotiate(std::string Signature);
132 std::error_code convertToErrorCode() const override;
133 void log(raw_ostream &OS) const override;
134 const std::string &getSignature() const { return Signature; }
136 std::string Signature;
139 template <typename DerivedFunc, typename FnT> class Function;
141 // RPC Function class.
142 // DerivedFunc should be a user defined class with a static 'getName()' method
143 // returning a const char* representing the function's name.
144 template <typename DerivedFunc, typename RetT, typename... ArgTs>
145 class Function<DerivedFunc, RetT(ArgTs...)> {
147 /// User defined function type.
148 using Type = RetT(ArgTs...);
151 using ReturnType = RetT;
153 /// Returns the full function prototype as a string.
154 static const char *getPrototype() {
155 std::lock_guard<std::mutex> Lock(NameMutex);
157 raw_string_ostream(Name)
158 << RPCTypeName<RetT>::getName() << " " << DerivedFunc::getName()
159 << "(" << llvm::orc::rpc::RPCTypeNameSequence<ArgTs...>() << ")";
164 static std::mutex NameMutex;
165 static std::string Name;
168 template <typename DerivedFunc, typename RetT, typename... ArgTs>
169 std::mutex Function<DerivedFunc, RetT(ArgTs...)>::NameMutex;
171 template <typename DerivedFunc, typename RetT, typename... ArgTs>
172 std::string Function<DerivedFunc, RetT(ArgTs...)>::Name;
174 /// Allocates RPC function ids during autonegotiation.
175 /// Specializations of this class must provide four members:
177 /// static T getInvalidId():
178 /// Should return a reserved id that will be used to represent missing
179 /// functions during autonegotiation.
181 /// static T getResponseId():
182 /// Should return a reserved id that will be used to send function responses
185 /// static T getNegotiateId():
186 /// Should return a reserved id for the negotiate function, which will be used
187 /// to negotiate ids for user defined functions.
189 /// template <typename Func> T allocate():
190 /// Allocate a unique id for function Func.
191 template <typename T, typename = void> class RPCFunctionIdAllocator;
193 /// This specialization of RPCFunctionIdAllocator provides a default
194 /// implementation for integral types.
195 template <typename T>
196 class RPCFunctionIdAllocator<
197 T, typename std::enable_if<std::is_integral<T>::value>::type> {
199 static T getInvalidId() { return T(0); }
200 static T getResponseId() { return T(1); }
201 static T getNegotiateId() { return T(2); }
203 template <typename Func> T allocate() { return NextId++; }
211 /// Provides a typedef for a tuple containing the decayed argument types.
212 template <typename T> class FunctionArgsTuple;
214 template <typename RetT, typename... ArgTs>
215 class FunctionArgsTuple<RetT(ArgTs...)> {
217 using Type = std::tuple<typename std::decay<
218 typename std::remove_reference<ArgTs>::type>::type...>;
221 // ResultTraits provides typedefs and utilities specific to the return type
223 template <typename RetT> class ResultTraits {
225 // The return type wrapped in llvm::Expected.
226 using ErrorReturnType = Expected<RetT>;
229 // The ErrorReturnType wrapped in a std::promise.
230 using ReturnPromiseType = std::promise<MSVCPExpected<RetT>>;
232 // The ErrorReturnType wrapped in a std::future.
233 using ReturnFutureType = std::future<MSVCPExpected<RetT>>;
235 // The ErrorReturnType wrapped in a std::promise.
236 using ReturnPromiseType = std::promise<ErrorReturnType>;
238 // The ErrorReturnType wrapped in a std::future.
239 using ReturnFutureType = std::future<ErrorReturnType>;
242 // Create a 'blank' value of the ErrorReturnType, ready and safe to
244 static ErrorReturnType createBlankErrorReturnValue() {
245 return ErrorReturnType(RetT());
248 // Consume an abandoned ErrorReturnType.
249 static void consumeAbandoned(ErrorReturnType RetOrErr) {
250 consumeError(RetOrErr.takeError());
254 // ResultTraits specialization for void functions.
255 template <> class ResultTraits<void> {
257 // For void functions, ErrorReturnType is llvm::Error.
258 using ErrorReturnType = Error;
261 // The ErrorReturnType wrapped in a std::promise.
262 using ReturnPromiseType = std::promise<MSVCPError>;
264 // The ErrorReturnType wrapped in a std::future.
265 using ReturnFutureType = std::future<MSVCPError>;
267 // The ErrorReturnType wrapped in a std::promise.
268 using ReturnPromiseType = std::promise<ErrorReturnType>;
270 // The ErrorReturnType wrapped in a std::future.
271 using ReturnFutureType = std::future<ErrorReturnType>;
274 // Create a 'blank' value of the ErrorReturnType, ready and safe to
276 static ErrorReturnType createBlankErrorReturnValue() {
277 return ErrorReturnType::success();
280 // Consume an abandoned ErrorReturnType.
281 static void consumeAbandoned(ErrorReturnType Err) {
282 consumeError(std::move(Err));
286 // ResultTraits<Error> is equivalent to ResultTraits<void>. This allows
287 // handlers for void RPC functions to return either void (in which case they
288 // implicitly succeed) or Error (in which case their error return is
289 // propagated). See usage in HandlerTraits::runHandlerHelper.
290 template <> class ResultTraits<Error> : public ResultTraits<void> {};
292 // ResultTraits<Expected<T>> is equivalent to ResultTraits<T>. This allows
293 // handlers for RPC functions returning a T to return either a T (in which
294 // case they implicitly succeed) or Expected<T> (in which case their error
295 // return is propagated). See usage in HandlerTraits::runHandlerHelper.
296 template <typename RetT>
297 class ResultTraits<Expected<RetT>> : public ResultTraits<RetT> {};
299 // Determines whether an RPC function's defined error return type supports
300 // error return value.
301 template <typename T>
302 class SupportsErrorReturn {
304 static const bool value = false;
308 class SupportsErrorReturn<Error> {
310 static const bool value = true;
313 template <typename T>
314 class SupportsErrorReturn<Expected<T>> {
316 static const bool value = true;
319 // RespondHelper packages return values based on whether or not the declared
320 // RPC function return type supports error returns.
321 template <bool FuncSupportsErrorReturn>
324 // RespondHelper specialization for functions that support error returns.
326 class RespondHelper<true> {
330 template <typename WireRetT, typename HandlerRetT, typename ChannelT,
331 typename FunctionIdT, typename SequenceNumberT>
332 static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
333 SequenceNumberT SeqNo,
334 Expected<HandlerRetT> ResultOrErr) {
335 if (!ResultOrErr && ResultOrErr.template errorIsA<RPCFatalError>())
336 return ResultOrErr.takeError();
338 // Open the response message.
339 if (auto Err = C.startSendMessage(ResponseId, SeqNo))
342 // Serialize the result.
344 SerializationTraits<ChannelT, WireRetT,
345 Expected<HandlerRetT>>::serialize(
346 C, std::move(ResultOrErr)))
349 // Close the response message.
350 return C.endSendMessage();
353 template <typename ChannelT, typename FunctionIdT, typename SequenceNumberT>
354 static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
355 SequenceNumberT SeqNo, Error Err) {
356 if (Err && Err.isA<RPCFatalError>())
358 if (auto Err2 = C.startSendMessage(ResponseId, SeqNo))
360 if (auto Err2 = serializeSeq(C, std::move(Err)))
362 return C.endSendMessage();
367 // RespondHelper specialization for functions that do not support error returns.
369 class RespondHelper<false> {
372 template <typename WireRetT, typename HandlerRetT, typename ChannelT,
373 typename FunctionIdT, typename SequenceNumberT>
374 static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
375 SequenceNumberT SeqNo,
376 Expected<HandlerRetT> ResultOrErr) {
377 if (auto Err = ResultOrErr.takeError())
380 // Open the response message.
381 if (auto Err = C.startSendMessage(ResponseId, SeqNo))
384 // Serialize the result.
386 SerializationTraits<ChannelT, WireRetT, HandlerRetT>::serialize(
390 // Close the response message.
391 return C.endSendMessage();
394 template <typename ChannelT, typename FunctionIdT, typename SequenceNumberT>
395 static Error sendResult(ChannelT &C, const FunctionIdT &ResponseId,
396 SequenceNumberT SeqNo, Error Err) {
399 if (auto Err2 = C.startSendMessage(ResponseId, SeqNo))
401 return C.endSendMessage();
407 // Send a response of the given wire return type (WireRetT) over the
408 // channel, with the given sequence number.
409 template <typename WireRetT, typename HandlerRetT, typename ChannelT,
410 typename FunctionIdT, typename SequenceNumberT>
411 Error respond(ChannelT &C, const FunctionIdT &ResponseId,
412 SequenceNumberT SeqNo, Expected<HandlerRetT> ResultOrErr) {
413 return RespondHelper<SupportsErrorReturn<WireRetT>::value>::
414 template sendResult<WireRetT>(C, ResponseId, SeqNo, std::move(ResultOrErr));
417 // Send an empty response message on the given channel to indicate that
419 template <typename WireRetT, typename ChannelT, typename FunctionIdT,
420 typename SequenceNumberT>
421 Error respond(ChannelT &C, const FunctionIdT &ResponseId, SequenceNumberT SeqNo,
423 return RespondHelper<SupportsErrorReturn<WireRetT>::value>::
424 sendResult(C, ResponseId, SeqNo, std::move(Err));
427 // Converts a given type to the equivalent error return type.
428 template <typename T> class WrappedHandlerReturn {
430 using Type = Expected<T>;
433 template <typename T> class WrappedHandlerReturn<Expected<T>> {
435 using Type = Expected<T>;
438 template <> class WrappedHandlerReturn<void> {
443 template <> class WrappedHandlerReturn<Error> {
448 template <> class WrappedHandlerReturn<ErrorSuccess> {
453 // Traits class that strips the response function from the list of handler
455 template <typename FnT> class AsyncHandlerTraits;
457 template <typename ResultT, typename... ArgTs>
458 class AsyncHandlerTraits<Error(std::function<Error(Expected<ResultT>)>, ArgTs...)> {
460 using Type = Error(ArgTs...);
461 using ResultType = Expected<ResultT>;
464 template <typename... ArgTs>
465 class AsyncHandlerTraits<Error(std::function<Error(Error)>, ArgTs...)> {
467 using Type = Error(ArgTs...);
468 using ResultType = Error;
471 template <typename... ArgTs>
472 class AsyncHandlerTraits<ErrorSuccess(std::function<Error(Error)>, ArgTs...)> {
474 using Type = Error(ArgTs...);
475 using ResultType = Error;
478 template <typename... ArgTs>
479 class AsyncHandlerTraits<void(std::function<Error(Error)>, ArgTs...)> {
481 using Type = Error(ArgTs...);
482 using ResultType = Error;
485 template <typename ResponseHandlerT, typename... ArgTs>
486 class AsyncHandlerTraits<Error(ResponseHandlerT, ArgTs...)> :
487 public AsyncHandlerTraits<Error(typename std::decay<ResponseHandlerT>::type,
490 // This template class provides utilities related to RPC function handlers.
491 // The base case applies to non-function types (the template class is
492 // specialized for function types) and inherits from the appropriate
493 // speciilization for the given non-function type's call operator.
494 template <typename HandlerT>
495 class HandlerTraits : public HandlerTraits<decltype(
496 &std::remove_reference<HandlerT>::type::operator())> {
499 // Traits for handlers with a given function type.
500 template <typename RetT, typename... ArgTs>
501 class HandlerTraits<RetT(ArgTs...)> {
503 // Function type of the handler.
504 using Type = RetT(ArgTs...);
506 // Return type of the handler.
507 using ReturnType = RetT;
509 // Call the given handler with the given arguments.
510 template <typename HandlerT, typename... TArgTs>
511 static typename WrappedHandlerReturn<RetT>::Type
512 unpackAndRun(HandlerT &Handler, std::tuple<TArgTs...> &Args) {
513 return unpackAndRunHelper(Handler, Args,
514 llvm::index_sequence_for<TArgTs...>());
517 // Call the given handler with the given arguments.
518 template <typename HandlerT, typename ResponderT, typename... TArgTs>
519 static Error unpackAndRunAsync(HandlerT &Handler, ResponderT &Responder,
520 std::tuple<TArgTs...> &Args) {
521 return unpackAndRunAsyncHelper(Handler, Responder, Args,
522 llvm::index_sequence_for<TArgTs...>());
525 // Call the given handler with the given arguments.
526 template <typename HandlerT>
527 static typename std::enable_if<
528 std::is_void<typename HandlerTraits<HandlerT>::ReturnType>::value,
530 run(HandlerT &Handler, ArgTs &&... Args) {
531 Handler(std::move(Args)...);
532 return Error::success();
535 template <typename HandlerT, typename... TArgTs>
536 static typename std::enable_if<
537 !std::is_void<typename HandlerTraits<HandlerT>::ReturnType>::value,
538 typename HandlerTraits<HandlerT>::ReturnType>::type
539 run(HandlerT &Handler, TArgTs... Args) {
540 return Handler(std::move(Args)...);
543 // Serialize arguments to the channel.
544 template <typename ChannelT, typename... CArgTs>
545 static Error serializeArgs(ChannelT &C, const CArgTs... CArgs) {
546 return SequenceSerialization<ChannelT, ArgTs...>::serialize(C, CArgs...);
549 // Deserialize arguments from the channel.
550 template <typename ChannelT, typename... CArgTs>
551 static Error deserializeArgs(ChannelT &C, std::tuple<CArgTs...> &Args) {
552 return deserializeArgsHelper(C, Args,
553 llvm::index_sequence_for<CArgTs...>());
557 template <typename ChannelT, typename... CArgTs, size_t... Indexes>
558 static Error deserializeArgsHelper(ChannelT &C, std::tuple<CArgTs...> &Args,
559 llvm::index_sequence<Indexes...> _) {
560 return SequenceSerialization<ChannelT, ArgTs...>::deserialize(
561 C, std::get<Indexes>(Args)...);
564 template <typename HandlerT, typename ArgTuple, size_t... Indexes>
565 static typename WrappedHandlerReturn<
566 typename HandlerTraits<HandlerT>::ReturnType>::Type
567 unpackAndRunHelper(HandlerT &Handler, ArgTuple &Args,
568 llvm::index_sequence<Indexes...>) {
569 return run(Handler, std::move(std::get<Indexes>(Args))...);
573 template <typename HandlerT, typename ResponderT, typename ArgTuple,
575 static typename WrappedHandlerReturn<
576 typename HandlerTraits<HandlerT>::ReturnType>::Type
577 unpackAndRunAsyncHelper(HandlerT &Handler, ResponderT &Responder,
579 llvm::index_sequence<Indexes...>) {
580 return run(Handler, Responder, std::move(std::get<Indexes>(Args))...);
584 // Handler traits for free functions.
585 template <typename RetT, typename... ArgTs>
586 class HandlerTraits<RetT(*)(ArgTs...)>
587 : public HandlerTraits<RetT(ArgTs...)> {};
589 // Handler traits for class methods (especially call operators for lambdas).
590 template <typename Class, typename RetT, typename... ArgTs>
591 class HandlerTraits<RetT (Class::*)(ArgTs...)>
592 : public HandlerTraits<RetT(ArgTs...)> {};
594 // Handler traits for const class methods (especially call operators for
596 template <typename Class, typename RetT, typename... ArgTs>
597 class HandlerTraits<RetT (Class::*)(ArgTs...) const>
598 : public HandlerTraits<RetT(ArgTs...)> {};
600 // Utility to peel the Expected wrapper off a response handler error type.
601 template <typename HandlerT> class ResponseHandlerArg;
603 template <typename ArgT> class ResponseHandlerArg<Error(Expected<ArgT>)> {
605 using ArgType = Expected<ArgT>;
606 using UnwrappedArgType = ArgT;
609 template <typename ArgT>
610 class ResponseHandlerArg<ErrorSuccess(Expected<ArgT>)> {
612 using ArgType = Expected<ArgT>;
613 using UnwrappedArgType = ArgT;
616 template <> class ResponseHandlerArg<Error(Error)> {
618 using ArgType = Error;
621 template <> class ResponseHandlerArg<ErrorSuccess(Error)> {
623 using ArgType = Error;
626 // ResponseHandler represents a handler for a not-yet-received function call
628 template <typename ChannelT> class ResponseHandler {
630 virtual ~ResponseHandler() {}
632 // Reads the function result off the wire and acts on it. The meaning of
633 // "act" will depend on how this method is implemented in any given
634 // ResponseHandler subclass but could, for example, mean running a
635 // user-specified handler or setting a promise value.
636 virtual Error handleResponse(ChannelT &C) = 0;
638 // Abandons this outstanding result.
639 virtual void abandon() = 0;
641 // Create an error instance representing an abandoned response.
642 static Error createAbandonedResponseError() {
643 return make_error<ResponseAbandoned>();
647 // ResponseHandler subclass for RPC functions with non-void returns.
648 template <typename ChannelT, typename FuncRetT, typename HandlerT>
649 class ResponseHandlerImpl : public ResponseHandler<ChannelT> {
651 ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
653 // Handle the result by deserializing it from the channel then passing it
654 // to the user defined handler.
655 Error handleResponse(ChannelT &C) override {
656 using UnwrappedArgType = typename ResponseHandlerArg<
657 typename HandlerTraits<HandlerT>::Type>::UnwrappedArgType;
658 UnwrappedArgType Result;
660 SerializationTraits<ChannelT, FuncRetT,
661 UnwrappedArgType>::deserialize(C, Result))
663 if (auto Err = C.endReceiveMessage())
665 return Handler(std::move(Result));
668 // Abandon this response by calling the handler with an 'abandoned response'
670 void abandon() override {
671 if (auto Err = Handler(this->createAbandonedResponseError())) {
672 // Handlers should not fail when passed an abandoned response error.
673 report_fatal_error(std::move(Err));
681 // ResponseHandler subclass for RPC functions with void returns.
682 template <typename ChannelT, typename HandlerT>
683 class ResponseHandlerImpl<ChannelT, void, HandlerT>
684 : public ResponseHandler<ChannelT> {
686 ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
688 // Handle the result (no actual value, just a notification that the function
689 // has completed on the remote end) by calling the user-defined handler with
691 Error handleResponse(ChannelT &C) override {
692 if (auto Err = C.endReceiveMessage())
694 return Handler(Error::success());
697 // Abandon this response by calling the handler with an 'abandoned response'
699 void abandon() override {
700 if (auto Err = Handler(this->createAbandonedResponseError())) {
701 // Handlers should not fail when passed an abandoned response error.
702 report_fatal_error(std::move(Err));
710 template <typename ChannelT, typename FuncRetT, typename HandlerT>
711 class ResponseHandlerImpl<ChannelT, Expected<FuncRetT>, HandlerT>
712 : public ResponseHandler<ChannelT> {
714 ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
716 // Handle the result by deserializing it from the channel then passing it
717 // to the user defined handler.
718 Error handleResponse(ChannelT &C) override {
719 using HandlerArgType = typename ResponseHandlerArg<
720 typename HandlerTraits<HandlerT>::Type>::ArgType;
721 HandlerArgType Result((typename HandlerArgType::value_type()));
724 SerializationTraits<ChannelT, Expected<FuncRetT>,
725 HandlerArgType>::deserialize(C, Result))
727 if (auto Err = C.endReceiveMessage())
729 return Handler(std::move(Result));
732 // Abandon this response by calling the handler with an 'abandoned response'
734 void abandon() override {
735 if (auto Err = Handler(this->createAbandonedResponseError())) {
736 // Handlers should not fail when passed an abandoned response error.
737 report_fatal_error(std::move(Err));
745 template <typename ChannelT, typename HandlerT>
746 class ResponseHandlerImpl<ChannelT, Error, HandlerT>
747 : public ResponseHandler<ChannelT> {
749 ResponseHandlerImpl(HandlerT Handler) : Handler(std::move(Handler)) {}
751 // Handle the result by deserializing it from the channel then passing it
752 // to the user defined handler.
753 Error handleResponse(ChannelT &C) override {
754 Error Result = Error::success();
756 SerializationTraits<ChannelT, Error, Error>::deserialize(C, Result))
758 if (auto Err = C.endReceiveMessage())
760 return Handler(std::move(Result));
763 // Abandon this response by calling the handler with an 'abandoned response'
765 void abandon() override {
766 if (auto Err = Handler(this->createAbandonedResponseError())) {
767 // Handlers should not fail when passed an abandoned response error.
768 report_fatal_error(std::move(Err));
776 // Create a ResponseHandler from a given user handler.
777 template <typename ChannelT, typename FuncRetT, typename HandlerT>
778 std::unique_ptr<ResponseHandler<ChannelT>> createResponseHandler(HandlerT H) {
779 return llvm::make_unique<ResponseHandlerImpl<ChannelT, FuncRetT, HandlerT>>(
783 // Helper for wrapping member functions up as functors. This is useful for
784 // installing methods as result handlers.
785 template <typename ClassT, typename RetT, typename... ArgTs>
786 class MemberFnWrapper {
788 using MethodT = RetT (ClassT::*)(ArgTs...);
789 MemberFnWrapper(ClassT &Instance, MethodT Method)
790 : Instance(Instance), Method(Method) {}
791 RetT operator()(ArgTs &&... Args) {
792 return (Instance.*Method)(std::move(Args)...);
800 // Helper that provides a Functor for deserializing arguments.
801 template <typename... ArgTs> class ReadArgs {
803 Error operator()() { return Error::success(); }
806 template <typename ArgT, typename... ArgTs>
807 class ReadArgs<ArgT, ArgTs...> : public ReadArgs<ArgTs...> {
809 ReadArgs(ArgT &Arg, ArgTs &... Args)
810 : ReadArgs<ArgTs...>(Args...), Arg(Arg) {}
812 Error operator()(ArgT &ArgVal, ArgTs &... ArgVals) {
813 this->Arg = std::move(ArgVal);
814 return ReadArgs<ArgTs...>::operator()(ArgVals...);
821 // Manage sequence numbers.
822 template <typename SequenceNumberT> class SequenceNumberManager {
824 // Reset, making all sequence numbers available.
826 std::lock_guard<std::mutex> Lock(SeqNoLock);
827 NextSequenceNumber = 0;
828 FreeSequenceNumbers.clear();
831 // Get the next available sequence number. Will re-use numbers that have
833 SequenceNumberT getSequenceNumber() {
834 std::lock_guard<std::mutex> Lock(SeqNoLock);
835 if (FreeSequenceNumbers.empty())
836 return NextSequenceNumber++;
837 auto SequenceNumber = FreeSequenceNumbers.back();
838 FreeSequenceNumbers.pop_back();
839 return SequenceNumber;
842 // Release a sequence number, making it available for re-use.
843 void releaseSequenceNumber(SequenceNumberT SequenceNumber) {
844 std::lock_guard<std::mutex> Lock(SeqNoLock);
845 FreeSequenceNumbers.push_back(SequenceNumber);
849 std::mutex SeqNoLock;
850 SequenceNumberT NextSequenceNumber = 0;
851 std::vector<SequenceNumberT> FreeSequenceNumbers;
854 // Checks that predicate P holds for each corresponding pair of type arguments
855 // from T1 and T2 tuple.
856 template <template <class, class> class P, typename T1Tuple, typename T2Tuple>
857 class RPCArgTypeCheckHelper;
859 template <template <class, class> class P>
860 class RPCArgTypeCheckHelper<P, std::tuple<>, std::tuple<>> {
862 static const bool value = true;
865 template <template <class, class> class P, typename T, typename... Ts,
866 typename U, typename... Us>
867 class RPCArgTypeCheckHelper<P, std::tuple<T, Ts...>, std::tuple<U, Us...>> {
869 static const bool value =
871 RPCArgTypeCheckHelper<P, std::tuple<Ts...>, std::tuple<Us...>>::value;
874 template <template <class, class> class P, typename T1Sig, typename T2Sig>
875 class RPCArgTypeCheck {
877 using T1Tuple = typename FunctionArgsTuple<T1Sig>::Type;
878 using T2Tuple = typename FunctionArgsTuple<T2Sig>::Type;
880 static_assert(std::tuple_size<T1Tuple>::value >=
881 std::tuple_size<T2Tuple>::value,
882 "Too many arguments to RPC call");
883 static_assert(std::tuple_size<T1Tuple>::value <=
884 std::tuple_size<T2Tuple>::value,
885 "Too few arguments to RPC call");
887 static const bool value = RPCArgTypeCheckHelper<P, T1Tuple, T2Tuple>::value;
890 template <typename ChannelT, typename WireT, typename ConcreteT>
893 using S = SerializationTraits<ChannelT, WireT, ConcreteT>;
895 template <typename T>
896 static std::true_type
897 check(typename std::enable_if<
898 std::is_same<decltype(T::serialize(std::declval<ChannelT &>(),
899 std::declval<const ConcreteT &>())),
903 template <typename> static std::false_type check(...);
906 static const bool value = decltype(check<S>(0))::value;
909 template <typename ChannelT, typename WireT, typename ConcreteT>
910 class CanDeserialize {
912 using S = SerializationTraits<ChannelT, WireT, ConcreteT>;
914 template <typename T>
915 static std::true_type
916 check(typename std::enable_if<
917 std::is_same<decltype(T::deserialize(std::declval<ChannelT &>(),
918 std::declval<ConcreteT &>())),
922 template <typename> static std::false_type check(...);
925 static const bool value = decltype(check<S>(0))::value;
928 /// Contains primitive utilities for defining, calling and handling calls to
929 /// remote procedures. ChannelT is a bidirectional stream conforming to the
930 /// RPCChannel interface (see RPCChannel.h), FunctionIdT is a procedure
931 /// identifier type that must be serializable on ChannelT, and SequenceNumberT
932 /// is an integral type that will be used to number in-flight function calls.
934 /// These utilities support the construction of very primitive RPC utilities.
935 /// Their intent is to ensure correct serialization and deserialization of
936 /// procedure arguments, and to keep the client and server's view of the API in
938 template <typename ImplT, typename ChannelT, typename FunctionIdT,
939 typename SequenceNumberT>
940 class RPCEndpointBase {
942 class OrcRPCInvalid : public Function<OrcRPCInvalid, void()> {
944 static const char *getName() { return "__orc_rpc$invalid"; }
947 class OrcRPCResponse : public Function<OrcRPCResponse, void()> {
949 static const char *getName() { return "__orc_rpc$response"; }
952 class OrcRPCNegotiate
953 : public Function<OrcRPCNegotiate, FunctionIdT(std::string)> {
955 static const char *getName() { return "__orc_rpc$negotiate"; }
958 // Helper predicate for testing for the presence of SerializeTraits
960 template <typename WireT, typename ConcreteT>
961 class CanSerializeCheck : detail::CanSerialize<ChannelT, WireT, ConcreteT> {
963 using detail::CanSerialize<ChannelT, WireT, ConcreteT>::value;
965 static_assert(value, "Missing serializer for argument (Can't serialize the "
966 "first template type argument of CanSerializeCheck "
970 // Helper predicate for testing for the presence of SerializeTraits
972 template <typename WireT, typename ConcreteT>
973 class CanDeserializeCheck
974 : detail::CanDeserialize<ChannelT, WireT, ConcreteT> {
976 using detail::CanDeserialize<ChannelT, WireT, ConcreteT>::value;
978 static_assert(value, "Missing deserializer for argument (Can't deserialize "
979 "the second template type argument of "
980 "CanDeserializeCheck from the first)");
984 /// Construct an RPC instance on a channel.
985 RPCEndpointBase(ChannelT &C, bool LazyAutoNegotiation)
986 : C(C), LazyAutoNegotiation(LazyAutoNegotiation) {
987 // Hold ResponseId in a special variable, since we expect Response to be
988 // called relatively frequently, and want to avoid the map lookup.
989 ResponseId = FnIdAllocator.getResponseId();
990 RemoteFunctionIds[OrcRPCResponse::getPrototype()] = ResponseId;
992 // Register the negotiate function id and handler.
993 auto NegotiateId = FnIdAllocator.getNegotiateId();
994 RemoteFunctionIds[OrcRPCNegotiate::getPrototype()] = NegotiateId;
995 Handlers[NegotiateId] = wrapHandler<OrcRPCNegotiate>(
996 [this](const std::string &Name) { return handleNegotiate(Name); });
1000 /// Negotiate a function id for Func with the other end of the channel.
1001 template <typename Func> Error negotiateFunction(bool Retry = false) {
1002 return getRemoteFunctionId<Func>(true, Retry).takeError();
1005 /// Append a call Func, does not call send on the channel.
1006 /// The first argument specifies a user-defined handler to be run when the
1007 /// function returns. The handler should take an Expected<Func::ReturnType>,
1008 /// or an Error (if Func::ReturnType is void). The handler will be called
1009 /// with an error if the return value is abandoned due to a channel error.
1010 template <typename Func, typename HandlerT, typename... ArgTs>
1011 Error appendCallAsync(HandlerT Handler, const ArgTs &... Args) {
1014 detail::RPCArgTypeCheck<CanSerializeCheck, typename Func::Type,
1015 void(ArgTs...)>::value,
1018 // Look up the function ID.
1020 if (auto FnIdOrErr = getRemoteFunctionId<Func>(LazyAutoNegotiation, false))
1023 // Negotiation failed. Notify the handler then return the negotiate-failed
1025 cantFail(Handler(make_error<ResponseAbandoned>()));
1026 return FnIdOrErr.takeError();
1029 SequenceNumberT SeqNo; // initialized in locked scope below.
1031 // Lock the pending responses map and sequence number manager.
1032 std::lock_guard<std::mutex> Lock(ResponsesMutex);
1034 // Allocate a sequence number.
1035 SeqNo = SequenceNumberMgr.getSequenceNumber();
1036 assert(!PendingResponses.count(SeqNo) &&
1037 "Sequence number already allocated");
1039 // Install the user handler.
1040 PendingResponses[SeqNo] =
1041 detail::createResponseHandler<ChannelT, typename Func::ReturnType>(
1042 std::move(Handler));
1045 // Open the function call message.
1046 if (auto Err = C.startSendMessage(FnId, SeqNo)) {
1047 abandonPendingResponses();
1051 // Serialize the call arguments.
1052 if (auto Err = detail::HandlerTraits<typename Func::Type>::serializeArgs(
1054 abandonPendingResponses();
1058 // Close the function call messagee.
1059 if (auto Err = C.endSendMessage()) {
1060 abandonPendingResponses();
1064 return Error::success();
1067 Error sendAppendedCalls() { return C.send(); };
1069 template <typename Func, typename HandlerT, typename... ArgTs>
1070 Error callAsync(HandlerT Handler, const ArgTs &... Args) {
1071 if (auto Err = appendCallAsync<Func>(std::move(Handler), Args...))
1076 /// Handle one incoming call.
1079 SequenceNumberT SeqNo;
1080 if (auto Err = C.startReceiveMessage(FnId, SeqNo)) {
1081 abandonPendingResponses();
1084 if (FnId == ResponseId)
1085 return handleResponse(SeqNo);
1086 auto I = Handlers.find(FnId);
1087 if (I != Handlers.end())
1088 return I->second(C, SeqNo);
1090 // else: No handler found. Report error to client?
1091 return make_error<BadFunctionCall<FunctionIdT, SequenceNumberT>>(FnId,
1095 /// Helper for handling setter procedures - this method returns a functor that
1096 /// sets the variables referred to by Args... to values deserialized from the
1100 /// typedef Function<0, bool, int> Func1;
1105 /// if (auto Err = expect<Func1>(Channel, readArgs(B, I)))
1106 /// /* Handle Args */ ;
1108 template <typename... ArgTs>
1109 static detail::ReadArgs<ArgTs...> readArgs(ArgTs &... Args) {
1110 return detail::ReadArgs<ArgTs...>(Args...);
1113 /// Abandon all outstanding result handlers.
1115 /// This will call all currently registered result handlers to receive an
1116 /// "abandoned" error as their argument. This is used internally by the RPC
1117 /// in error situations, but can also be called directly by clients who are
1118 /// disconnecting from the remote and don't or can't expect responses to their
1119 /// outstanding calls. (Especially for outstanding blocking calls, calling
1120 /// this function may be necessary to avoid dead threads).
1121 void abandonPendingResponses() {
1122 // Lock the pending responses map and sequence number manager.
1123 std::lock_guard<std::mutex> Lock(ResponsesMutex);
1125 for (auto &KV : PendingResponses)
1126 KV.second->abandon();
1127 PendingResponses.clear();
1128 SequenceNumberMgr.reset();
1131 /// Remove the handler for the given function.
1132 /// A handler must currently be registered for this function.
1133 template <typename Func>
1134 void removeHandler() {
1135 auto IdItr = LocalFunctionIds.find(Func::getPrototype());
1136 assert(IdItr != LocalFunctionIds.end() &&
1137 "Function does not have a registered handler");
1138 auto HandlerItr = Handlers.find(IdItr->second);
1139 assert(HandlerItr != Handlers.end() &&
1140 "Function does not have a registered handler");
1141 Handlers.erase(HandlerItr);
1144 /// Clear all handlers.
1145 void clearHandlers() {
1151 FunctionIdT getInvalidFunctionId() const {
1152 return FnIdAllocator.getInvalidId();
1155 /// Add the given handler to the handler map and make it available for
1156 /// autonegotiation and execution.
1157 template <typename Func, typename HandlerT>
1158 void addHandlerImpl(HandlerT Handler) {
1160 static_assert(detail::RPCArgTypeCheck<
1161 CanDeserializeCheck, typename Func::Type,
1162 typename detail::HandlerTraits<HandlerT>::Type>::value,
1165 FunctionIdT NewFnId = FnIdAllocator.template allocate<Func>();
1166 LocalFunctionIds[Func::getPrototype()] = NewFnId;
1167 Handlers[NewFnId] = wrapHandler<Func>(std::move(Handler));
1170 template <typename Func, typename HandlerT>
1171 void addAsyncHandlerImpl(HandlerT Handler) {
1173 static_assert(detail::RPCArgTypeCheck<
1174 CanDeserializeCheck, typename Func::Type,
1175 typename detail::AsyncHandlerTraits<
1176 typename detail::HandlerTraits<HandlerT>::Type
1180 FunctionIdT NewFnId = FnIdAllocator.template allocate<Func>();
1181 LocalFunctionIds[Func::getPrototype()] = NewFnId;
1182 Handlers[NewFnId] = wrapAsyncHandler<Func>(std::move(Handler));
1185 Error handleResponse(SequenceNumberT SeqNo) {
1186 using Handler = typename decltype(PendingResponses)::mapped_type;
1190 // Lock the pending responses map and sequence number manager.
1191 std::unique_lock<std::mutex> Lock(ResponsesMutex);
1192 auto I = PendingResponses.find(SeqNo);
1194 if (I != PendingResponses.end()) {
1195 PRHandler = std::move(I->second);
1196 PendingResponses.erase(I);
1197 SequenceNumberMgr.releaseSequenceNumber(SeqNo);
1199 // Unlock the pending results map to prevent recursive lock.
1201 abandonPendingResponses();
1203 InvalidSequenceNumberForResponse<SequenceNumberT>>(SeqNo);
1208 "If we didn't find a response handler we should have bailed out");
1210 if (auto Err = PRHandler->handleResponse(C)) {
1211 abandonPendingResponses();
1215 return Error::success();
1218 FunctionIdT handleNegotiate(const std::string &Name) {
1219 auto I = LocalFunctionIds.find(Name);
1220 if (I == LocalFunctionIds.end())
1221 return getInvalidFunctionId();
1225 // Find the remote FunctionId for the given function.
1226 template <typename Func>
1227 Expected<FunctionIdT> getRemoteFunctionId(bool NegotiateIfNotInMap,
1228 bool NegotiateIfInvalid) {
1231 // Check if we already have a function id...
1232 auto I = RemoteFunctionIds.find(Func::getPrototype());
1233 if (I != RemoteFunctionIds.end()) {
1234 // If it's valid there's nothing left to do.
1235 if (I->second != getInvalidFunctionId())
1237 DoNegotiate = NegotiateIfInvalid;
1239 DoNegotiate = NegotiateIfNotInMap;
1241 // We don't have a function id for Func yet, but we're allowed to try to
1244 auto &Impl = static_cast<ImplT &>(*this);
1245 if (auto RemoteIdOrErr =
1246 Impl.template callB<OrcRPCNegotiate>(Func::getPrototype())) {
1247 RemoteFunctionIds[Func::getPrototype()] = *RemoteIdOrErr;
1248 if (*RemoteIdOrErr == getInvalidFunctionId())
1249 return make_error<CouldNotNegotiate>(Func::getPrototype());
1250 return *RemoteIdOrErr;
1252 return RemoteIdOrErr.takeError();
1255 // No key was available in the map and we weren't allowed to try to
1256 // negotiate one, so return an unknown function error.
1257 return make_error<CouldNotNegotiate>(Func::getPrototype());
1260 using WrappedHandlerFn = std::function<Error(ChannelT &, SequenceNumberT)>;
1262 // Wrap the given user handler in the necessary argument-deserialization code,
1263 // result-serialization code, and call to the launch policy (if present).
1264 template <typename Func, typename HandlerT>
1265 WrappedHandlerFn wrapHandler(HandlerT Handler) {
1266 return [this, Handler](ChannelT &Channel,
1267 SequenceNumberT SeqNo) mutable -> Error {
1268 // Start by deserializing the arguments.
1270 typename detail::FunctionArgsTuple<
1271 typename detail::HandlerTraits<HandlerT>::Type>::Type;
1272 auto Args = std::make_shared<ArgsTuple>();
1275 detail::HandlerTraits<typename Func::Type>::deserializeArgs(
1279 // GCC 4.7 and 4.8 incorrectly issue a -Wunused-but-set-variable warning
1280 // for RPCArgs. Void cast RPCArgs to work around this for now.
1281 // FIXME: Remove this workaround once we can assume a working GCC version.
1284 // End receieve message, unlocking the channel for reading.
1285 if (auto Err = Channel.endReceiveMessage())
1288 using HTraits = detail::HandlerTraits<HandlerT>;
1289 using FuncReturn = typename Func::ReturnType;
1290 return detail::respond<FuncReturn>(Channel, ResponseId, SeqNo,
1291 HTraits::unpackAndRun(Handler, *Args));
1295 // Wrap the given user handler in the necessary argument-deserialization code,
1296 // result-serialization code, and call to the launch policy (if present).
1297 template <typename Func, typename HandlerT>
1298 WrappedHandlerFn wrapAsyncHandler(HandlerT Handler) {
1299 return [this, Handler](ChannelT &Channel,
1300 SequenceNumberT SeqNo) mutable -> Error {
1301 // Start by deserializing the arguments.
1302 using AHTraits = detail::AsyncHandlerTraits<
1303 typename detail::HandlerTraits<HandlerT>::Type>;
1305 typename detail::FunctionArgsTuple<typename AHTraits::Type>::Type;
1306 auto Args = std::make_shared<ArgsTuple>();
1309 detail::HandlerTraits<typename Func::Type>::deserializeArgs(
1313 // GCC 4.7 and 4.8 incorrectly issue a -Wunused-but-set-variable warning
1314 // for RPCArgs. Void cast RPCArgs to work around this for now.
1315 // FIXME: Remove this workaround once we can assume a working GCC version.
1318 // End receieve message, unlocking the channel for reading.
1319 if (auto Err = Channel.endReceiveMessage())
1322 using HTraits = detail::HandlerTraits<HandlerT>;
1323 using FuncReturn = typename Func::ReturnType;
1325 [this, SeqNo](typename AHTraits::ResultType RetVal) -> Error {
1326 return detail::respond<FuncReturn>(C, ResponseId, SeqNo,
1330 return HTraits::unpackAndRunAsync(Handler, Responder, *Args);
1336 bool LazyAutoNegotiation;
1338 RPCFunctionIdAllocator<FunctionIdT> FnIdAllocator;
1340 FunctionIdT ResponseId;
1341 std::map<std::string, FunctionIdT> LocalFunctionIds;
1342 std::map<const char *, FunctionIdT> RemoteFunctionIds;
1344 std::map<FunctionIdT, WrappedHandlerFn> Handlers;
1346 std::mutex ResponsesMutex;
1347 detail::SequenceNumberManager<SequenceNumberT> SequenceNumberMgr;
1348 std::map<SequenceNumberT, std::unique_ptr<detail::ResponseHandler<ChannelT>>>
1352 } // end namespace detail
1354 template <typename ChannelT, typename FunctionIdT = uint32_t,
1355 typename SequenceNumberT = uint32_t>
1356 class MultiThreadedRPCEndpoint
1357 : public detail::RPCEndpointBase<
1358 MultiThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
1359 ChannelT, FunctionIdT, SequenceNumberT> {
1362 detail::RPCEndpointBase<
1363 MultiThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
1364 ChannelT, FunctionIdT, SequenceNumberT>;
1367 MultiThreadedRPCEndpoint(ChannelT &C, bool LazyAutoNegotiation)
1368 : BaseClass(C, LazyAutoNegotiation) {}
1370 /// Add a handler for the given RPC function.
1371 /// This installs the given handler functor for the given RPC Function, and
1372 /// makes the RPC function available for negotiation/calling from the remote.
1373 template <typename Func, typename HandlerT>
1374 void addHandler(HandlerT Handler) {
1375 return this->template addHandlerImpl<Func>(std::move(Handler));
1378 /// Add a class-method as a handler.
1379 template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
1380 void addHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
1382 detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
1385 template <typename Func, typename HandlerT>
1386 void addAsyncHandler(HandlerT Handler) {
1387 return this->template addAsyncHandlerImpl<Func>(std::move(Handler));
1390 /// Add a class-method as a handler.
1391 template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
1392 void addAsyncHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
1393 addAsyncHandler<Func>(
1394 detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
1397 /// Return type for non-blocking call primitives.
1398 template <typename Func>
1399 using NonBlockingCallResult = typename detail::ResultTraits<
1400 typename Func::ReturnType>::ReturnFutureType;
1402 /// Call Func on Channel C. Does not block, does not call send. Returns a pair
1403 /// of a future result and the sequence number assigned to the result.
1405 /// This utility function is primarily used for single-threaded mode support,
1406 /// where the sequence number can be used to wait for the corresponding
1407 /// result. In multi-threaded mode the appendCallNB method, which does not
1408 /// return the sequence numeber, should be preferred.
1409 template <typename Func, typename... ArgTs>
1410 Expected<NonBlockingCallResult<Func>> appendCallNB(const ArgTs &... Args) {
1411 using RTraits = detail::ResultTraits<typename Func::ReturnType>;
1412 using ErrorReturn = typename RTraits::ErrorReturnType;
1413 using ErrorReturnPromise = typename RTraits::ReturnPromiseType;
1415 // FIXME: Stack allocate and move this into the handler once LLVM builds
1417 auto Promise = std::make_shared<ErrorReturnPromise>();
1418 auto FutureResult = Promise->get_future();
1420 if (auto Err = this->template appendCallAsync<Func>(
1421 [Promise](ErrorReturn RetOrErr) {
1422 Promise->set_value(std::move(RetOrErr));
1423 return Error::success();
1426 RTraits::consumeAbandoned(FutureResult.get());
1427 return std::move(Err);
1429 return std::move(FutureResult);
1432 /// The same as appendCallNBWithSeq, except that it calls C.send() to
1433 /// flush the channel after serializing the call.
1434 template <typename Func, typename... ArgTs>
1435 Expected<NonBlockingCallResult<Func>> callNB(const ArgTs &... Args) {
1436 auto Result = appendCallNB<Func>(Args...);
1439 if (auto Err = this->C.send()) {
1440 this->abandonPendingResponses();
1441 detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
1442 std::move(Result->get()));
1443 return std::move(Err);
1448 /// Call Func on Channel C. Blocks waiting for a result. Returns an Error
1449 /// for void functions or an Expected<T> for functions returning a T.
1451 /// This function is for use in threaded code where another thread is
1452 /// handling responses and incoming calls.
1453 template <typename Func, typename... ArgTs,
1454 typename AltRetT = typename Func::ReturnType>
1455 typename detail::ResultTraits<AltRetT>::ErrorReturnType
1456 callB(const ArgTs &... Args) {
1457 if (auto FutureResOrErr = callNB<Func>(Args...))
1458 return FutureResOrErr->get();
1460 return FutureResOrErr.takeError();
1463 /// Handle incoming RPC calls.
1464 Error handlerLoop() {
1466 if (auto Err = this->handleOne())
1468 return Error::success();
1472 template <typename ChannelT, typename FunctionIdT = uint32_t,
1473 typename SequenceNumberT = uint32_t>
1474 class SingleThreadedRPCEndpoint
1475 : public detail::RPCEndpointBase<
1476 SingleThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
1477 ChannelT, FunctionIdT, SequenceNumberT> {
1480 detail::RPCEndpointBase<
1481 SingleThreadedRPCEndpoint<ChannelT, FunctionIdT, SequenceNumberT>,
1482 ChannelT, FunctionIdT, SequenceNumberT>;
1485 SingleThreadedRPCEndpoint(ChannelT &C, bool LazyAutoNegotiation)
1486 : BaseClass(C, LazyAutoNegotiation) {}
1488 template <typename Func, typename HandlerT>
1489 void addHandler(HandlerT Handler) {
1490 return this->template addHandlerImpl<Func>(std::move(Handler));
1493 template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
1494 void addHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
1496 detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
1499 template <typename Func, typename HandlerT>
1500 void addAsyncHandler(HandlerT Handler) {
1501 return this->template addAsyncHandlerImpl<Func>(std::move(Handler));
1504 /// Add a class-method as a handler.
1505 template <typename Func, typename ClassT, typename RetT, typename... ArgTs>
1506 void addAsyncHandler(ClassT &Object, RetT (ClassT::*Method)(ArgTs...)) {
1507 addAsyncHandler<Func>(
1508 detail::MemberFnWrapper<ClassT, RetT, ArgTs...>(Object, Method));
1511 template <typename Func, typename... ArgTs,
1512 typename AltRetT = typename Func::ReturnType>
1513 typename detail::ResultTraits<AltRetT>::ErrorReturnType
1514 callB(const ArgTs &... Args) {
1515 bool ReceivedResponse = false;
1516 using ResultType = typename detail::ResultTraits<AltRetT>::ErrorReturnType;
1517 auto Result = detail::ResultTraits<AltRetT>::createBlankErrorReturnValue();
1519 // We have to 'Check' result (which we know is in a success state at this
1520 // point) so that it can be overwritten in the async handler.
1523 if (auto Err = this->template appendCallAsync<Func>(
1525 Result = std::move(R);
1526 ReceivedResponse = true;
1527 return Error::success();
1530 detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
1532 return std::move(Err);
1535 while (!ReceivedResponse) {
1536 if (auto Err = this->handleOne()) {
1537 detail::ResultTraits<typename Func::ReturnType>::consumeAbandoned(
1539 return std::move(Err);
1547 /// Asynchronous dispatch for a function on an RPC endpoint.
1548 template <typename RPCClass, typename Func>
1549 class RPCAsyncDispatch {
1551 RPCAsyncDispatch(RPCClass &Endpoint) : Endpoint(Endpoint) {}
1553 template <typename HandlerT, typename... ArgTs>
1554 Error operator()(HandlerT Handler, const ArgTs &... Args) const {
1555 return Endpoint.template appendCallAsync<Func>(std::move(Handler), Args...);
1562 /// Construct an asynchronous dispatcher from an RPC endpoint and a Func.
1563 template <typename Func, typename RPCEndpointT>
1564 RPCAsyncDispatch<RPCEndpointT, Func> rpcAsyncDispatch(RPCEndpointT &Endpoint) {
1565 return RPCAsyncDispatch<RPCEndpointT, Func>(Endpoint);
1568 /// Allows a set of asynchrounous calls to be dispatched, and then
1569 /// waited on as a group.
1570 class ParallelCallGroup {
1573 ParallelCallGroup() = default;
1574 ParallelCallGroup(const ParallelCallGroup &) = delete;
1575 ParallelCallGroup &operator=(const ParallelCallGroup &) = delete;
1577 /// Make as asynchronous call.
1578 template <typename AsyncDispatcher, typename HandlerT, typename... ArgTs>
1579 Error call(const AsyncDispatcher &AsyncDispatch, HandlerT Handler,
1580 const ArgTs &... Args) {
1581 // Increment the count of outstanding calls. This has to happen before
1582 // we invoke the call, as the handler may (depending on scheduling)
1583 // be run immediately on another thread, and we don't want the decrement
1584 // in the wrapped handler below to run before the increment.
1586 std::unique_lock<std::mutex> Lock(M);
1587 ++NumOutstandingCalls;
1590 // Wrap the user handler in a lambda that will decrement the
1591 // outstanding calls count, then poke the condition variable.
1592 using ArgType = typename detail::ResponseHandlerArg<
1593 typename detail::HandlerTraits<HandlerT>::Type>::ArgType;
1594 // FIXME: Move handler into wrapped handler once we have C++14.
1595 auto WrappedHandler = [this, Handler](ArgType Arg) {
1596 auto Err = Handler(std::move(Arg));
1597 std::unique_lock<std::mutex> Lock(M);
1598 --NumOutstandingCalls;
1603 return AsyncDispatch(std::move(WrappedHandler), Args...);
1606 /// Blocks until all calls have been completed and their return value
1609 std::unique_lock<std::mutex> Lock(M);
1610 while (NumOutstandingCalls > 0)
1616 std::condition_variable CV;
1617 uint32_t NumOutstandingCalls = 0;
1620 /// Convenience class for grouping RPC Functions into APIs that can be
1621 /// negotiated as a block.
1623 template <typename... Funcs>
1627 /// Test whether this API contains Function F.
1628 template <typename F>
1631 static const bool value = false;
1634 /// Negotiate all functions in this API.
1635 template <typename RPCEndpoint>
1636 static Error negotiate(RPCEndpoint &R) {
1637 return Error::success();
1641 template <typename Func, typename... Funcs>
1642 class APICalls<Func, Funcs...> {
1645 template <typename F>
1648 static const bool value = std::is_same<F, Func>::value |
1649 APICalls<Funcs...>::template Contains<F>::value;
1652 template <typename RPCEndpoint>
1653 static Error negotiate(RPCEndpoint &R) {
1654 if (auto Err = R.template negotiateFunction<Func>())
1656 return APICalls<Funcs...>::negotiate(R);
1661 template <typename... InnerFuncs, typename... Funcs>
1662 class APICalls<APICalls<InnerFuncs...>, Funcs...> {
1665 template <typename F>
1668 static const bool value =
1669 APICalls<InnerFuncs...>::template Contains<F>::value |
1670 APICalls<Funcs...>::template Contains<F>::value;
1673 template <typename RPCEndpoint>
1674 static Error negotiate(RPCEndpoint &R) {
1675 if (auto Err = APICalls<InnerFuncs...>::negotiate(R))
1677 return APICalls<Funcs...>::negotiate(R);
1682 } // end namespace rpc
1683 } // end namespace orc
1684 } // end namespace llvm