1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef INCLUDE_PERFETTO_IPC_ASYNC_RESULT_H_ 18 #define INCLUDE_PERFETTO_IPC_ASYNC_RESULT_H_ 19 20 #include <memory> 21 #include <type_traits> 22 #include <utility> 23 24 #include "perfetto/ipc/basic_types.h" 25 26 namespace perfetto { 27 namespace ipc { 28 29 // Wraps the result of an asynchronous invocation. This is the equivalent of a 30 // std::pair<unique_ptr<T>, bool> with syntactic sugar. It is used as callback 31 // argument by Deferred<T>. 32 template <typename T = ProtoMessage> 33 class AsyncResult { 34 public: 35 static AsyncResult Create() { 36 return AsyncResult(std::unique_ptr<T>(new T())); 37 } 38 39 AsyncResult(std::unique_ptr<T> msg = nullptr, 40 bool has_more = false, 41 int fd = -1) 42 : msg_(std::move(msg)), has_more_(has_more), fd_(fd) { 43 static_assert(std::is_base_of<ProtoMessage, T>::value, "T->ProtoMessage"); 44 } 45 AsyncResult(AsyncResult&&) noexcept = default; 46 AsyncResult& operator=(AsyncResult&&) = default; 47 48 bool success() const { return !!msg_; } 49 explicit operator bool() const { return success(); } 50 51 bool has_more() const { return has_more_; } 52 void set_has_more(bool has_more) { has_more_ = has_more; } 53 54 void set_msg(std::unique_ptr<T> msg) { msg_ = std::move(msg); } 55 T* release_msg() { return msg_.release(); } 56 T* operator->() { return msg_.get(); } 57 T& operator*() { return *msg_; } 58 59 void set_fd(int fd) { fd_ = fd; } 60 int fd() const { return fd_; } 61 62 private: 63 std::unique_ptr<T> msg_; 64 bool has_more_ = false; 65 66 // Optional. Only for messages that convey a file descriptor, for sharing 67 // memory across processes. 68 int fd_ = -1; 69 }; 70 71 } // namespace ipc 72 } // namespace perfetto 73 74 #endif // INCLUDE_PERFETTO_IPC_ASYNC_RESULT_H_ 75
