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_TRACING_CORE_SLICE_H_ 18 #define INCLUDE_PERFETTO_TRACING_CORE_SLICE_H_ 19 20 #include <stddef.h> 21 #include <string.h> 22 23 #include <memory> 24 #include <string> 25 #include <vector> 26 27 #include "perfetto/base/logging.h" 28 29 namespace perfetto { 30 31 // A simple wrapper around a virtually contiguous memory range that contains a 32 // TracePacket, or just a portion of it. 33 struct Slice { SliceSlice34 Slice() : start(nullptr), size(0) {} SliceSlice35 Slice(const void* st, size_t sz) : start(st), size(sz) {} 36 37 // Used to inherit ownership of a buffer from a protobuf via release_str(). SliceSlice38 explicit Slice(std::unique_ptr<std::string> str) 39 : start(&(*str)[0]), size(str->size()), moved_str_data_(std::move(str)) {} 40 41 Slice(Slice&& other) noexcept = default; 42 43 // Create a Slice which owns |size| bytes of memory. AllocateSlice44 static Slice Allocate(size_t size) { 45 Slice slice; 46 slice.own_data_.reset(new uint8_t[size]); 47 slice.start = &slice.own_data_[0]; 48 slice.size = size; 49 return slice; 50 } 51 own_dataSlice52 uint8_t* own_data() { 53 PERFETTO_DCHECK(own_data_); 54 return own_data_.get(); 55 } 56 57 const void* start; 58 size_t size; 59 60 private: 61 Slice(const Slice&) = delete; 62 void operator=(const Slice&) = delete; 63 64 std::unique_ptr<uint8_t[]> own_data_; 65 std::unique_ptr<std::string> moved_str_data_; 66 }; 67 68 // TODO(primiano): most TracePacket(s) fit in a slice or two. We need something 69 // a bit more clever here that has inline capacity for 2 slices and then uses a 70 // std::forward_list or a std::vector for the less likely cases. 71 using Slices = std::vector<Slice>; 72 73 } // namespace perfetto 74 75 #endif // INCLUDE_PERFETTO_TRACING_CORE_SLICE_H_ 76