1 /* 2 * Copyright (C) 2021 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_TRACING_TRACED_VALUE_FORWARD_H_ 18 #define INCLUDE_PERFETTO_TRACING_TRACED_VALUE_FORWARD_H_ 19 20 namespace perfetto { 21 22 class TracedValue; 23 class TracedArray; 24 class TracedDictionary; 25 template <typename MessageType> 26 class TracedProto; 27 28 template <typename T> 29 void WriteIntoTracedValue(TracedValue context, T&& value); 30 template <typename MessageType, typename T> 31 void WriteIntoTracedProto(TracedProto<MessageType> context, T&& value); 32 33 template <typename T, class = void> 34 struct TraceFormatTraits; 35 36 // Helpers to check whether a given type T can be written into a TracedValue / 37 // TracedProto<MessageType>. 38 // 39 // Intended to be used for types like smart pointers, who should support 40 // WriteIntoTrace only iff their inner type supports being written into 41 // a TracedValue. 42 // 43 // template <typename T> 44 // class SmartPtr { 45 // ... 46 // 47 // // Note: |Check| is needed to ensure that using 48 // SmartPtr<ClassWhichDoesNotSupportTracedValue> does not generate a 49 // compilation error. 50 // 51 // template <typename Check=void> 52 // typename check_traced_value_support<T, Check>::value 53 // WriteIntoTrace(perfetto::TracedValue context) const { 54 // WriteIntoTracedValue(std::move(context), *ptr_); 55 // } 56 // 57 // template <typename MessageType> 58 // typename check_traced_value_support<T, MessageType>::value 59 // WriteIntoTrace(perfetto::TracedProto<MessageType> message) const { 60 // WriteIntoTracedProto(std::move(message), *ptr_); 61 // } 62 // }; 63 template <typename T, typename ResultType = void, typename = void> 64 struct check_traced_value_support; 65 66 template <typename MessageType, 67 typename T, 68 typename ResultType = void, 69 typename = void> 70 struct check_traced_proto_support; 71 72 } // namespace perfetto 73 74 #endif // INCLUDE_PERFETTO_TRACING_TRACED_VALUE_FORWARD_H_ 75