| #ifndef ANDROID_PDX_RPC_REMOTE_METHOD_H_ |
| #define ANDROID_PDX_RPC_REMOTE_METHOD_H_ |
| |
| #include <tuple> |
| #include <type_traits> |
| |
| #include <pdx/client.h> |
| #include <pdx/rpc/argument_encoder.h> |
| #include <pdx/rpc/message_buffer.h> |
| #include <pdx/rpc/payload.h> |
| #include <pdx/rpc/remote_method_type.h> |
| #include <pdx/service.h> |
| #include <pdx/status.h> |
| |
| namespace android { |
| namespace pdx { |
| namespace rpc { |
| |
| #ifdef __clang__ |
| // Stand-in type to avoid Clang compiler bug. Clang currently has a bug where |
| // performing parameter pack expansion for arguments with empty packs causes a |
| // compiler crash. Provide a substitute void type and specializations/overloads |
| // of CheckArgumentTypes and DispatchRemoteMethod to work around this problem. |
| struct Void {}; |
| |
| // Evaluates to true if the method type is <any>(Void), false otherwise. |
| template <typename RemoteMethodType> |
| using IsVoidMethod = typename std::integral_constant< |
| bool, RemoteMethodType::Traits::Arity == 1 && |
| std::is_same<typename RemoteMethodType::Traits::template Arg<0>, |
| Void>::value>; |
| |
| // Utility to determine if a method is of type <any>(Void). |
| template <typename RemoteMethodType> |
| using EnableIfVoidMethod = |
| typename std::enable_if<IsVoidMethod<RemoteMethodType>::value>::type; |
| |
| // Utility to determine if a method is not of type <any>(Void). |
| template <typename RemoteMethodType> |
| using EnableIfNotVoidMethod = |
| typename std::enable_if<!IsVoidMethod<RemoteMethodType>::value>::type; |
| |
| #else |
| // GCC works fine with void argument types, always enable the regular |
| // implementation of DispatchRemoteMethod. |
| using Void = void; |
| template <typename RemoteMethodType> |
| using EnableIfVoidMethod = void; |
| template <typename RemoteMethodType> |
| using EnableIfNotVoidMethod = void; |
| #endif |
| |
| // Helper type trait to specialize InvokeRemoteMethods for return types that |
| // can be obtained directly from Transaction::Send<T>() without deserializing |
| // reply payload. |
| template <typename T> |
| struct IsDirectReturn : std::false_type {}; |
| |
| template <> |
| struct IsDirectReturn<void> : std::true_type {}; |
| |
| template <> |
| struct IsDirectReturn<int> : std::true_type {}; |
| |
| template <> |
| struct IsDirectReturn<LocalHandle> : std::true_type {}; |
| |
| template <> |
| struct IsDirectReturn<LocalChannelHandle> : std::true_type {}; |
| |
| template <typename Return, typename Type = void> |
| using EnableIfDirectReturn = |
| typename std::enable_if<IsDirectReturn<Return>::value, Type>::type; |
| |
| template <typename Return, typename Type = void> |
| using EnableIfNotDirectReturn = |
| typename std::enable_if<!IsDirectReturn<Return>::value, Type>::type; |
| |
| // Utility class to invoke a method with arguments packed in a tuple. |
| template <typename Class, typename T> |
| class UnpackArguments; |
| |
| // Utility class to invoke a method with arguments packed in a tuple. |
| template <typename Class, typename Return, typename... Args> |
| class UnpackArguments<Class, Return(Args...)> { |
| public: |
| using ArgsTupleType = std::tuple<typename std::decay<Args>::type...>; |
| using MethodType = Return (Class::*)(Message&, Args...); |
| |
| UnpackArguments(Class& instance, MethodType method, Message& message, |
| ArgsTupleType& parameters) |
| : instance_(instance), |
| method_(method), |
| message_(message), |
| parameters_(parameters) {} |
| |
| // Invokes method_ on intance_ with the packed arguments from parameters_. |
| Return Invoke() { |
| constexpr auto Arity = sizeof...(Args); |
| return static_cast<Return>(InvokeHelper(MakeIndexSequence<Arity>{})); |
| } |
| |
| private: |
| Class& instance_; |
| MethodType method_; |
| Message& message_; |
| ArgsTupleType& parameters_; |
| |
| template <std::size_t... Index> |
| Return InvokeHelper(IndexSequence<Index...>) { |
| return static_cast<Return>((instance_.*method_)( |
| message_, |
| std::get<Index>(std::forward<ArgsTupleType>(parameters_))...)); |
| } |
| |
| UnpackArguments(const UnpackArguments&) = delete; |
| void operator=(const UnpackArguments&) = delete; |
| }; |
| |
| // Returns an error code from a remote method to the client. May be called |
| // either during dispatch of the remote method handler or at a later time if the |
| // message is moved for delayed response. |
| inline void RemoteMethodError(Message& message, int error_code) { |
| const auto status = message.ReplyError(error_code); |
| ALOGE_IF(!status, "RemoteMethodError: Failed to reply to message: %s", |
| status.GetErrorMessage().c_str()); |
| } |
| |
| // Returns a value from a remote method to the client. The usual method to |
| // return a value during dispatch of a remote method is to simply use a return |
| // statement in the handler. If the message is moved however, these methods may |
| // be used to return a value at a later time, outside of initial dispatch. |
| |
| // Overload for direct return types. |
| template <typename RemoteMethodType, typename Return> |
| EnableIfDirectReturn<typename RemoteMethodType::Return> RemoteMethodReturn( |
| Message& message, const Return& return_value) { |
| const auto status = message.Reply(return_value); |
| ALOGE_IF(!status, "RemoteMethodReturn: Failed to reply to message: %s", |
| status.GetErrorMessage().c_str()); |
| } |
| |
| // Overload for non-direct return types. |
| template <typename RemoteMethodType, typename Return> |
| EnableIfNotDirectReturn<typename RemoteMethodType::Return> RemoteMethodReturn( |
| Message& message, const Return& return_value) { |
| using Signature = typename RemoteMethodType::template RewriteReturn<Return>; |
| rpc::ServicePayload<ReplyBuffer> payload(message); |
| MakeArgumentEncoder<Signature>(&payload).EncodeReturn(return_value); |
| |
| auto ret = message.WriteAll(payload.Data(), payload.Size()); |
| auto status = message.Reply(ret); |
| ALOGE_IF(!status, "RemoteMethodReturn: Failed to reply to message: %s", |
| status.GetErrorMessage().c_str()); |
| } |
| |
| // Overload for Status<void> return types. |
| template <typename RemoteMethodType> |
| void RemoteMethodReturn(Message& message, const Status<void>& return_value) { |
| if (return_value) |
| RemoteMethodReturn<RemoteMethodType>(message, 0); |
| else |
| RemoteMethodError(message, return_value.error()); |
| } |
| |
| // Overload for Status<T> return types. This overload forwards the underlying |
| // value or error within the Status<T>. |
| template <typename RemoteMethodType, typename Return> |
| void RemoteMethodReturn(Message& message, const Status<Return>& return_value) { |
| if (return_value) |
| RemoteMethodReturn<RemoteMethodType, Return>(message, return_value.get()); |
| else |
| RemoteMethodError(message, return_value.error()); |
| } |
| |
| // Dispatches a method by deserializing arguments from the given Message, with |
| // compile-time interface check. Overload for void return types. |
| template <typename RemoteMethodType, typename Class, typename... Args, |
| typename = EnableIfNotVoidMethod<RemoteMethodType>> |
| void DispatchRemoteMethod(Class& instance, |
| void (Class::*method)(Message&, Args...), |
| Message& message, |
| std::size_t max_capacity = InitialBufferCapacity) { |
| using Signature = typename RemoteMethodType::template RewriteArgs<Args...>; |
| rpc::ServicePayload<ReceiveBuffer> payload(message); |
| payload.Resize(max_capacity); |
| |
| Status<size_t> read_status = message.Read(payload.Data(), payload.Size()); |
| if (!read_status) { |
| RemoteMethodError(message, read_status.error()); |
| return; |
| } |
| |
| payload.Resize(read_status.get()); |
| |
| ErrorType error; |
| auto decoder = MakeArgumentDecoder<Signature>(&payload); |
| auto arguments = decoder.DecodeArguments(&error); |
| if (error) { |
| RemoteMethodError(message, EIO); |
| return; |
| } |
| |
| UnpackArguments<Class, Signature>(instance, method, message, arguments) |
| .Invoke(); |
| // Return to the caller unless the message was moved. |
| if (message) |
| RemoteMethodReturn<RemoteMethodType>(message, 0); |
| } |
| |
| // Dispatches a method by deserializing arguments from the given Message, with |
| // compile-time interface signature check. Overload for generic return types. |
| template <typename RemoteMethodType, typename Class, typename Return, |
| typename... Args, typename = EnableIfNotVoidMethod<RemoteMethodType>> |
| void DispatchRemoteMethod(Class& instance, |
| Return (Class::*method)(Message&, Args...), |
| Message& message, |
| std::size_t max_capacity = InitialBufferCapacity) { |
| using Signature = |
| typename RemoteMethodType::template RewriteSignature<Return, Args...>; |
| rpc::ServicePayload<ReceiveBuffer> payload(message); |
| payload.Resize(max_capacity); |
| |
| Status<size_t> read_status = message.Read(payload.Data(), payload.Size()); |
| if (!read_status) { |
| RemoteMethodError(message, read_status.error()); |
| return; |
| } |
| |
| payload.Resize(read_status.get()); |
| |
| ErrorType error; |
| auto decoder = MakeArgumentDecoder<Signature>(&payload); |
| auto arguments = decoder.DecodeArguments(&error); |
| if (error) { |
| RemoteMethodError(message, EIO); |
| return; |
| } |
| |
| auto return_value = |
| UnpackArguments<Class, Signature>(instance, method, message, arguments) |
| .Invoke(); |
| // Return the value to the caller unless the message was moved. |
| if (message) |
| RemoteMethodReturn<RemoteMethodType>(message, return_value); |
| } |
| |
| // Dispatches a method by deserializing arguments from the given Message, with |
| // compile-time interface signature check. Overload for Status<T> return types. |
| template <typename RemoteMethodType, typename Class, typename Return, |
| typename... Args, typename = EnableIfNotVoidMethod<RemoteMethodType>> |
| void DispatchRemoteMethod(Class& instance, |
| Status<Return> (Class::*method)(Message&, Args...), |
| Message& message, |
| std::size_t max_capacity = InitialBufferCapacity) { |
| using Signature = |
| typename RemoteMethodType::template RewriteSignature<Return, Args...>; |
| using InvokeSignature = |
| typename RemoteMethodType::template RewriteSignatureWrapReturn< |
| Status, Return, Args...>; |
| rpc::ServicePayload<ReceiveBuffer> payload(message); |
| payload.Resize(max_capacity); |
| |
| Status<size_t> read_status = message.Read(payload.Data(), payload.Size()); |
| if (!read_status) { |
| RemoteMethodError(message, read_status.error()); |
| return; |
| } |
| |
| payload.Resize(read_status.get()); |
| |
| ErrorType error; |
| auto decoder = MakeArgumentDecoder<Signature>(&payload); |
| auto arguments = decoder.DecodeArguments(&error); |
| if (error) { |
| RemoteMethodError(message, EIO); |
| return; |
| } |
| |
| auto return_value = UnpackArguments<Class, InvokeSignature>( |
| instance, method, message, arguments) |
| .Invoke(); |
| // Return the value to the caller unless the message was moved. |
| if (message) |
| RemoteMethodReturn<RemoteMethodType>(message, return_value); |
| } |
| |
| #ifdef __clang__ |
| // Overloads to handle Void argument type without exploding clang. |
| |
| // Overload for void return type. |
| template <typename RemoteMethodType, typename Class, |
| typename = EnableIfVoidMethod<RemoteMethodType>> |
| void DispatchRemoteMethod(Class& instance, void (Class::*method)(Message&), |
| Message& message) { |
| (instance.*method)(message); |
| // Return to the caller unless the message was moved. |
| if (message) |
| RemoteMethodReturn<RemoteMethodType>(message, 0); |
| } |
| |
| // Overload for generic return type. |
| template <typename RemoteMethodType, typename Class, typename Return, |
| typename = EnableIfVoidMethod<RemoteMethodType>> |
| void DispatchRemoteMethod(Class& instance, Return (Class::*method)(Message&), |
| Message& message) { |
| auto return_value = (instance.*method)(message); |
| // Return the value to the caller unless the message was moved. |
| if (message) |
| RemoteMethodReturn<RemoteMethodType>(message, return_value); |
| } |
| |
| // Overload for Status<T> return type. |
| template <typename RemoteMethodType, typename Class, typename Return, |
| typename = EnableIfVoidMethod<RemoteMethodType>> |
| void DispatchRemoteMethod(Class& instance, |
| Status<Return> (Class::*method)(Message&), |
| Message& message) { |
| auto return_value = (instance.*method)(message); |
| // Return the value to the caller unless the message was moved. |
| if (message) |
| RemoteMethodReturn<RemoteMethodType>(message, return_value); |
| } |
| #endif |
| |
| } // namespace rpc |
| |
| // Definitions for template methods declared in pdx/client.h. |
| |
| template <int Opcode, typename T> |
| struct CheckArgumentTypes; |
| |
| template <int Opcode, typename Return, typename... Args> |
| struct CheckArgumentTypes<Opcode, Return(Args...)> { |
| template <typename R> |
| static typename rpc::EnableIfDirectReturn<R, Status<R>> Invoke(Client& client, |
| Args... args) { |
| Transaction trans{client}; |
| rpc::ClientPayload<rpc::SendBuffer> payload{trans}; |
| rpc::MakeArgumentEncoder<Return(Args...)>(&payload).EncodeArguments( |
| std::forward<Args>(args)...); |
| return trans.Send<R>(Opcode, payload.Data(), payload.Size(), nullptr, 0); |
| } |
| |
| template <typename R> |
| static typename rpc::EnableIfNotDirectReturn<R, Status<R>> Invoke( |
| Client& client, Args... args) { |
| Transaction trans{client}; |
| |
| rpc::ClientPayload<rpc::SendBuffer> send_payload{trans}; |
| rpc::MakeArgumentEncoder<Return(Args...)>(&send_payload) |
| .EncodeArguments(std::forward<Args>(args)...); |
| |
| rpc::ClientPayload<rpc::ReplyBuffer> reply_payload{trans}; |
| reply_payload.Resize(reply_payload.Capacity()); |
| |
| Status<R> result; |
| auto status = |
| trans.Send<void>(Opcode, send_payload.Data(), send_payload.Size(), |
| reply_payload.Data(), reply_payload.Size()); |
| if (!status) { |
| result.SetError(status.error()); |
| } else { |
| R return_value; |
| rpc::ErrorType error = |
| rpc::MakeArgumentDecoder<Return(Args...)>(&reply_payload) |
| .DecodeReturn(&return_value); |
| |
| switch (error.error_code()) { |
| case rpc::ErrorCode::NO_ERROR: |
| result.SetValue(std::move(return_value)); |
| break; |
| |
| // This error is returned when ArrayWrapper/StringWrapper is too |
| // small to receive the payload. |
| case rpc::ErrorCode::INSUFFICIENT_DESTINATION_SIZE: |
| result.SetError(ENOBUFS); |
| break; |
| |
| default: |
| result.SetError(EIO); |
| break; |
| } |
| } |
| return result; |
| } |
| |
| template <typename R> |
| static typename rpc::EnableIfDirectReturn<R, Status<void>> InvokeInPlace( |
| Client& client, R* return_value, Args... args) { |
| Transaction trans{client}; |
| |
| rpc::ClientPayload<rpc::SendBuffer> send_payload{trans}; |
| rpc::MakeArgumentEncoder<Return(Args...)>(&send_payload) |
| .EncodeArguments(std::forward<Args>(args)...); |
| |
| Status<void> result; |
| auto status = trans.Send<R>(Opcode, send_payload.Data(), |
| send_payload.Size(), nullptr, 0); |
| if (status) { |
| *return_value = status.take(); |
| result.SetValue(); |
| } else { |
| result.SetError(status.error()); |
| } |
| return result; |
| } |
| |
| template <typename R> |
| static typename rpc::EnableIfNotDirectReturn<R, Status<void>> InvokeInPlace( |
| Client& client, R* return_value, Args... args) { |
| Transaction trans{client}; |
| |
| rpc::ClientPayload<rpc::SendBuffer> send_payload{trans}; |
| rpc::MakeArgumentEncoder<Return(Args...)>(&send_payload) |
| .EncodeArguments(std::forward<Args>(args)...); |
| |
| rpc::ClientPayload<rpc::ReplyBuffer> reply_payload{trans}; |
| reply_payload.Resize(reply_payload.Capacity()); |
| |
| auto result = |
| trans.Send<void>(Opcode, send_payload.Data(), send_payload.Size(), |
| reply_payload.Data(), reply_payload.Size()); |
| if (result) { |
| rpc::ErrorType error = |
| rpc::MakeArgumentDecoder<Return(Args...)>(&reply_payload) |
| .DecodeReturn(return_value); |
| |
| switch (error.error_code()) { |
| case rpc::ErrorCode::NO_ERROR: |
| result.SetValue(); |
| break; |
| |
| // This error is returned when ArrayWrapper/StringWrapper is too |
| // small to receive the payload. |
| case rpc::ErrorCode::INSUFFICIENT_DESTINATION_SIZE: |
| result.SetError(ENOBUFS); |
| break; |
| |
| default: |
| result.SetError(EIO); |
| break; |
| } |
| } |
| return result; |
| } |
| }; |
| |
| // Invokes the remote method with opcode and signature described by |
| // |RemoteMethodType|. |
| template <typename RemoteMethodType, typename... Args> |
| Status<typename RemoteMethodType::Return> Client::InvokeRemoteMethod( |
| Args&&... args) { |
| return CheckArgumentTypes< |
| RemoteMethodType::Opcode, |
| typename RemoteMethodType::template RewriteArgs<Args...>>:: |
| template Invoke<typename RemoteMethodType::Return>( |
| *this, std::forward<Args>(args)...); |
| } |
| |
| template <typename RemoteMethodType, typename Return, typename... Args> |
| Status<void> Client::InvokeRemoteMethodInPlace(Return* return_value, |
| Args&&... args) { |
| return CheckArgumentTypes< |
| RemoteMethodType::Opcode, |
| typename RemoteMethodType::template RewriteSignature<Return, Args...>>:: |
| template InvokeInPlace(*this, return_value, std::forward<Args>(args)...); |
| } |
| |
| } // namespace pdx |
| } // namespace android |
| |
| #endif // ANDROID_PDX_RPC_REMOTE_METHOD_H_ |