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Diffstat (limited to 'Utilities/cmcppdap/include/dap/session.h')
| -rw-r--r-- | Utilities/cmcppdap/include/dap/session.h | 449 |
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diff --git a/Utilities/cmcppdap/include/dap/session.h b/Utilities/cmcppdap/include/dap/session.h new file mode 100644 index 0000000..3933886 --- /dev/null +++ b/Utilities/cmcppdap/include/dap/session.h @@ -0,0 +1,449 @@ +// Copyright 2019 Google LLC +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef dap_session_h +#define dap_session_h + +#include "future.h" +#include "io.h" +#include "traits.h" +#include "typeinfo.h" +#include "typeof.h" + +#include <functional> + +namespace dap { + +// Forward declarations +struct Request; +struct Response; +struct Event; + +//////////////////////////////////////////////////////////////////////////////// +// Error +//////////////////////////////////////////////////////////////////////////////// + +// Error represents an error message in response to a DAP request. +struct Error { + Error() = default; + Error(const std::string& error); + Error(const char* msg, ...); + + // operator bool() returns true if there is an error. + inline operator bool() const { return message.size() > 0; } + + std::string message; // empty represents success. +}; + +//////////////////////////////////////////////////////////////////////////////// +// ResponseOrError<T> +//////////////////////////////////////////////////////////////////////////////// + +// ResponseOrError holds either the response to a DAP request or an error +// message. +template <typename T> +struct ResponseOrError { + using Request = T; + + inline ResponseOrError() = default; + inline ResponseOrError(const T& response); + inline ResponseOrError(T&& response); + inline ResponseOrError(const Error& error); + inline ResponseOrError(Error&& error); + inline ResponseOrError(const ResponseOrError& other); + inline ResponseOrError(ResponseOrError&& other); + + inline ResponseOrError& operator=(const ResponseOrError& other); + inline ResponseOrError& operator=(ResponseOrError&& other); + + T response; + Error error; // empty represents success. +}; + +template <typename T> +ResponseOrError<T>::ResponseOrError(const T& resp) : response(resp) {} +template <typename T> +ResponseOrError<T>::ResponseOrError(T&& resp) : response(std::move(resp)) {} +template <typename T> +ResponseOrError<T>::ResponseOrError(const Error& err) : error(err) {} +template <typename T> +ResponseOrError<T>::ResponseOrError(Error&& err) : error(std::move(err)) {} +template <typename T> +ResponseOrError<T>::ResponseOrError(const ResponseOrError& other) + : response(other.response), error(other.error) {} +template <typename T> +ResponseOrError<T>::ResponseOrError(ResponseOrError&& other) + : response(std::move(other.response)), error(std::move(other.error)) {} +template <typename T> +ResponseOrError<T>& ResponseOrError<T>::operator=( + const ResponseOrError& other) { + response = other.response; + error = other.error; + return *this; +} +template <typename T> +ResponseOrError<T>& ResponseOrError<T>::operator=(ResponseOrError&& other) { + response = std::move(other.response); + error = std::move(other.error); + return *this; +} + +//////////////////////////////////////////////////////////////////////////////// +// Session +//////////////////////////////////////////////////////////////////////////////// + +// Session implements a DAP client or server endpoint. +// The general usage is as follows: +// (1) Create a session with Session::create(). +// (2) Register request and event handlers with registerHandler(). +// (3) Optionally register a protocol error handler with onError(). +// (3) Bind the session to the remote endpoint with bind(). +// (4) Send requests or events with send(). +class Session { + template <typename F, int N> + using ParamType = traits::ParameterType<F, N>; + + template <typename T> + using IsRequest = traits::EnableIfIsType<dap::Request, T>; + + template <typename T> + using IsEvent = traits::EnableIfIsType<dap::Event, T>; + + template <typename F> + using IsRequestHandlerWithoutCallback = traits::EnableIf< + traits::CompatibleWith<F, std::function<void(dap::Request)>>::value>; + + template <typename F, typename CallbackType> + using IsRequestHandlerWithCallback = traits::EnableIf<traits::CompatibleWith< + F, + std::function<void(dap::Request, std::function<void(CallbackType)>)>>:: + value>; + + public: + virtual ~Session(); + + // ErrorHandler is the type of callback function used for reporting protocol + // errors. + using ErrorHandler = std::function<void(const char*)>; + + // ClosedHandler is the type of callback function used to signal that a + // connected endpoint has closed. + using ClosedHandler = std::function<void()>; + + // create() constructs and returns a new Session. + static std::unique_ptr<Session> create(); + + // onError() registers a error handler that will be called whenever a protocol + // error is encountered. + // Only one error handler can be bound at any given time, and later calls + // will replace the existing error handler. + virtual void onError(const ErrorHandler&) = 0; + + // registerHandler() registers a request handler for a specific request type. + // The function F must have one of the following signatures: + // ResponseOrError<ResponseType>(const RequestType&) + // ResponseType(const RequestType&) + // Error(const RequestType&) + template <typename F, typename RequestType = ParamType<F, 0>> + inline IsRequestHandlerWithoutCallback<F> registerHandler(F&& handler); + + // registerHandler() registers a request handler for a specific request type. + // The handler has a response callback function for the second argument of the + // handler function. This callback may be called after the handler has + // returned. + // The function F must have the following signature: + // void(const RequestType& request, + // std::function<void(ResponseType)> response) + template <typename F, + typename RequestType = ParamType<F, 0>, + typename ResponseType = typename RequestType::Response> + inline IsRequestHandlerWithCallback<F, ResponseType> registerHandler( + F&& handler); + + // registerHandler() registers a request handler for a specific request type. + // The handler has a response callback function for the second argument of the + // handler function. This callback may be called after the handler has + // returned. + // The function F must have the following signature: + // void(const RequestType& request, + // std::function<void(ResponseOrError<ResponseType>)> response) + template <typename F, + typename RequestType = ParamType<F, 0>, + typename ResponseType = typename RequestType::Response> + inline IsRequestHandlerWithCallback<F, ResponseOrError<ResponseType>> + registerHandler(F&& handler); + + // registerHandler() registers a event handler for a specific event type. + // The function F must have the following signature: + // void(const EventType&) + template <typename F, typename EventType = ParamType<F, 0>> + inline IsEvent<EventType> registerHandler(F&& handler); + + // registerSentHandler() registers the function F to be called when a response + // of the specific type has been sent. + // The function F must have the following signature: + // void(const ResponseOrError<ResponseType>&) + template <typename F, + typename ResponseType = typename ParamType<F, 0>::Request> + inline void registerSentHandler(F&& handler); + + // send() sends the request to the connected endpoint and returns a + // future that is assigned the request response or error. + template <typename T, typename = IsRequest<T>> + future<ResponseOrError<typename T::Response>> send(const T& request); + + // send() sends the event to the connected endpoint. + template <typename T, typename = IsEvent<T>> + void send(const T& event); + + // bind() connects this Session to an endpoint using connect(), and then + // starts processing incoming messages with startProcessingMessages(). + // onClose is the optional callback which will be called when the session + // endpoint has been closed. + inline void bind(const std::shared_ptr<Reader>& reader, + const std::shared_ptr<Writer>& writer, + const ClosedHandler& onClose); + inline void bind(const std::shared_ptr<ReaderWriter>& readerWriter, + const ClosedHandler& onClose); + + ////////////////////////////////////////////////////////////////////////////// + // Note: + // Methods and members below this point are for advanced usage, and are more + // likely to change signature than the methods above. + // The methods above this point should be sufficient for most use cases. + ////////////////////////////////////////////////////////////////////////////// + + // connect() connects this Session to an endpoint. + // connect() can only be called once. Repeated calls will raise an error, but + // otherwise will do nothing. + // Note: This method is used for explicit control over message handling. + // Most users will use bind() instead of calling this method directly. + virtual void connect(const std::shared_ptr<Reader>&, + const std::shared_ptr<Writer>&) = 0; + inline void connect(const std::shared_ptr<ReaderWriter>&); + + // startProcessingMessages() starts a new thread to receive and dispatch + // incoming messages. + // onClose is the optional callback which will be called when the session + // endpoint has been closed. + // Note: This method is used for explicit control over message handling. + // Most users will use bind() instead of calling this method directly. + virtual void startProcessingMessages(const ClosedHandler& onClose = {}) = 0; + + // getPayload() blocks until the next incoming message is received, returning + // the payload or an empty function if the connection was lost. The returned + // payload is function that can be called on any thread to dispatch the + // message to the Session handler. + // Note: This method is used for explicit control over message handling. + // Most users will use bind() instead of calling this method directly. + virtual std::function<void()> getPayload() = 0; + + // The callback function type called when a request handler is invoked, and + // the request returns a successful result. + // 'responseTypeInfo' is the type information of the response data structure. + // 'responseData' is a pointer to response payload data. + using RequestHandlerSuccessCallback = + std::function<void(const TypeInfo* responseTypeInfo, + const void* responseData)>; + + // The callback function type used to notify when a DAP request fails. + // 'responseTypeInfo' is the type information of the response data structure. + // 'message' is the error message + using RequestHandlerErrorCallback = + std::function<void(const TypeInfo* responseTypeInfo, + const Error& message)>; + + // The callback function type used to invoke a request handler. + // 'request' is a pointer to the request data structure + // 'onSuccess' is the function to call if the request completed succesfully. + // 'onError' is the function to call if the request failed. + // For each call of the request handler, 'onSuccess' or 'onError' must be + // called exactly once. + using GenericRequestHandler = + std::function<void(const void* request, + const RequestHandlerSuccessCallback& onSuccess, + const RequestHandlerErrorCallback& onError)>; + + // The callback function type used to handle a response to a request. + // 'response' is a pointer to the response data structure. May be nullptr. + // 'error' is a pointer to the reponse error message. May be nullptr. + // One of 'data' or 'error' will be nullptr. + using GenericResponseHandler = + std::function<void(const void* response, const Error* error)>; + + // The callback function type used to handle an event. + // 'event' is a pointer to the event data structure. + using GenericEventHandler = std::function<void(const void* event)>; + + // The callback function type used to notify when a response has been sent + // from this session endpoint. + // 'response' is a pointer to the response data structure. + // 'error' is a pointer to the reponse error message. May be nullptr. + using GenericResponseSentHandler = + std::function<void(const void* response, const Error* error)>; + + // registerHandler() registers 'handler' as the request handler callback for + // requests of the type 'typeinfo'. + virtual void registerHandler(const TypeInfo* typeinfo, + const GenericRequestHandler& handler) = 0; + + // registerHandler() registers 'handler' as the event handler callback for + // events of the type 'typeinfo'. + virtual void registerHandler(const TypeInfo* typeinfo, + const GenericEventHandler& handler) = 0; + + // registerHandler() registers 'handler' as the response-sent handler function + // which is called whenever a response of the type 'typeinfo' is sent from + // this session endpoint. + virtual void registerHandler(const TypeInfo* typeinfo, + const GenericResponseSentHandler& handler) = 0; + + // send() sends a request to the remote endpoint. + // 'requestTypeInfo' is the type info of the request data structure. + // 'requestTypeInfo' is the type info of the response data structure. + // 'request' is a pointer to the request data structure. + // 'responseHandler' is the handler function for the response. + virtual bool send(const dap::TypeInfo* requestTypeInfo, + const dap::TypeInfo* responseTypeInfo, + const void* request, + const GenericResponseHandler& responseHandler) = 0; + + // send() sends an event to the remote endpoint. + // 'eventTypeInfo' is the type info for the event data structure. + // 'event' is a pointer to the event data structure. + virtual bool send(const TypeInfo* eventTypeInfo, const void* event) = 0; +}; + +template <typename F, typename RequestType> +Session::IsRequestHandlerWithoutCallback<F> Session::registerHandler( + F&& handler) { + using ResponseType = typename RequestType::Response; + const TypeInfo* typeinfo = TypeOf<RequestType>::type(); + registerHandler(typeinfo, + [handler](const void* args, + const RequestHandlerSuccessCallback& onSuccess, + const RequestHandlerErrorCallback& onError) { + ResponseOrError<ResponseType> res = + handler(*reinterpret_cast<const RequestType*>(args)); + if (res.error) { + onError(TypeOf<ResponseType>::type(), res.error); + } else { + onSuccess(TypeOf<ResponseType>::type(), &res.response); + } + }); +} + +template <typename F, typename RequestType, typename ResponseType> +Session::IsRequestHandlerWithCallback<F, ResponseType> Session::registerHandler( + F&& handler) { + using CallbackType = ParamType<F, 1>; + registerHandler( + TypeOf<RequestType>::type(), + [handler](const void* args, + const RequestHandlerSuccessCallback& onSuccess, + const RequestHandlerErrorCallback&) { + CallbackType responseCallback = [onSuccess](const ResponseType& res) { + onSuccess(TypeOf<ResponseType>::type(), &res); + }; + handler(*reinterpret_cast<const RequestType*>(args), responseCallback); + }); +} + +template <typename F, typename RequestType, typename ResponseType> +Session::IsRequestHandlerWithCallback<F, ResponseOrError<ResponseType>> +Session::registerHandler(F&& handler) { + using CallbackType = ParamType<F, 1>; + registerHandler( + TypeOf<RequestType>::type(), + [handler](const void* args, + const RequestHandlerSuccessCallback& onSuccess, + const RequestHandlerErrorCallback& onError) { + CallbackType responseCallback = + [onError, onSuccess](const ResponseOrError<ResponseType>& res) { + if (res.error) { + onError(TypeOf<ResponseType>::type(), res.error); + } else { + onSuccess(TypeOf<ResponseType>::type(), &res.response); + } + }; + handler(*reinterpret_cast<const RequestType*>(args), responseCallback); + }); +} + +template <typename F, typename T> +Session::IsEvent<T> Session::registerHandler(F&& handler) { + auto cb = [handler](const void* args) { + handler(*reinterpret_cast<const T*>(args)); + }; + const TypeInfo* typeinfo = TypeOf<T>::type(); + registerHandler(typeinfo, cb); +} + +template <typename F, typename T> +void Session::registerSentHandler(F&& handler) { + auto cb = [handler](const void* response, const Error* error) { + if (error != nullptr) { + handler(ResponseOrError<T>(*error)); + } else { + handler(ResponseOrError<T>(*reinterpret_cast<const T*>(response))); + } + }; + const TypeInfo* typeinfo = TypeOf<T>::type(); + registerHandler(typeinfo, cb); +} + +template <typename T, typename> +future<ResponseOrError<typename T::Response>> Session::send(const T& request) { + using Response = typename T::Response; + promise<ResponseOrError<Response>> promise; + auto sent = send(TypeOf<T>::type(), TypeOf<Response>::type(), &request, + [=](const void* result, const Error* error) { + if (error != nullptr) { + promise.set_value(ResponseOrError<Response>(*error)); + } else { + promise.set_value(ResponseOrError<Response>( + *reinterpret_cast<const Response*>(result))); + } + }); + if (!sent) { + promise.set_value(Error("Failed to send request")); + } + return promise.get_future(); +} + +template <typename T, typename> +void Session::send(const T& event) { + const TypeInfo* typeinfo = TypeOf<T>::type(); + send(typeinfo, &event); +} + +void Session::connect(const std::shared_ptr<ReaderWriter>& rw) { + connect(rw, rw); +} + +void Session::bind(const std::shared_ptr<dap::Reader>& r, + const std::shared_ptr<dap::Writer>& w, + const ClosedHandler& onClose = {}) { + connect(r, w); + startProcessingMessages(onClose); +} + +void Session::bind(const std::shared_ptr<ReaderWriter>& rw, + const ClosedHandler& onClose = {}) { + bind(rw, rw, onClose); +} + +} // namespace dap + +#endif // dap_session_h |