1 /* 2 * Copyright (C) 2019 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 SRC_TRACING_CORE_METATRACE_WRITER_H_ 18 #define SRC_TRACING_CORE_METATRACE_WRITER_H_ 19 20 #include <functional> 21 #include <memory> 22 23 #include "perfetto/ext/base/metatrace.h" 24 #include "perfetto/ext/base/thread_checker.h" 25 #include "perfetto/ext/base/weak_ptr.h" 26 27 namespace perfetto { 28 29 namespace base { 30 class TaskRunner; 31 } 32 33 class TraceWriter; 34 35 // Complements the base::metatrace infrastructure. 36 // It hooks a callback to metatrace::Enable() and writes metatrace events into 37 // a TraceWriter whenever the metatrace ring buffer is half full. 38 // It is safe to create and attempt to start multiple instances of this class, 39 // however only the first one will succeed because the metatrace framework 40 // doesn't support multiple instances. 41 // This class is defined here (instead of directly in src/probes/) so it can 42 // be reused by other components (e.g. heapprofd). 43 class MetatraceWriter { 44 public: 45 static constexpr char kDataSourceName[] = "perfetto.metatrace"; 46 47 MetatraceWriter(); 48 ~MetatraceWriter(); 49 50 MetatraceWriter(const MetatraceWriter&) = delete; 51 MetatraceWriter& operator=(const MetatraceWriter&) = delete; 52 MetatraceWriter(MetatraceWriter&&) = delete; 53 MetatraceWriter& operator=(MetatraceWriter&&) = delete; 54 55 void Enable(base::TaskRunner*, std::unique_ptr<TraceWriter>, uint32_t tags); 56 void Disable(); 57 void WriteAllAndFlushTraceWriter(std::function<void()> callback); 58 59 private: 60 void WriteAllAvailableEvents(); 61 62 bool started_ = false; 63 base::TaskRunner* task_runner_ = nullptr; 64 std::unique_ptr<TraceWriter> trace_writer_; 65 PERFETTO_THREAD_CHECKER(thread_checker_) 66 base::WeakPtrFactory<MetatraceWriter> weak_ptr_factory_; // Keep last. 67 }; 68 69 } // namespace perfetto 70 71 #endif // SRC_TRACING_CORE_METATRACE_WRITER_H_ 72