Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 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 | |
Alexander Timin | 97d8785 | 2021-05-17 18:01:33 +0000 | [diff] [blame^] | 17 | #ifndef SRC_TRACE_PROCESSOR_UTIL_TRACE_BLOB_VIEW_H_ |
| 18 | #define SRC_TRACE_PROCESSOR_UTIL_TRACE_BLOB_VIEW_H_ |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 19 | |
| 20 | #include <stddef.h> |
| 21 | #include <stdint.h> |
Primiano Tucci | 81d0a39 | 2018-09-04 15:15:37 +0100 | [diff] [blame] | 22 | |
| 23 | #include <limits> |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 24 | #include <memory> |
| 25 | |
| 26 | #include "perfetto/base/logging.h" |
| 27 | |
| 28 | namespace perfetto { |
| 29 | namespace trace_processor { |
| 30 | |
| 31 | // This class is an equivalent of std::string_view for trace binary data. |
| 32 | // The main difference is that this class has also shared ownership of a portion |
| 33 | // of the raw trace. |
| 34 | // The underlying buffer will be freed once all the TraceBlobViews that refer |
| 35 | // to the same buffer have passed through the pipeline and been parsed. |
| 36 | class TraceBlobView { |
| 37 | public: |
| 38 | TraceBlobView(std::unique_ptr<uint8_t[]> buffer, size_t offset, size_t length) |
| 39 | : shbuf_(SharedBuf(std::move(buffer))), |
Primiano Tucci | 81d0a39 | 2018-09-04 15:15:37 +0100 | [diff] [blame] | 40 | offset_(static_cast<uint32_t>(offset)), |
| 41 | length_(static_cast<uint32_t>(length)) { |
| 42 | PERFETTO_DCHECK(offset <= std::numeric_limits<uint32_t>::max()); |
| 43 | PERFETTO_DCHECK(length <= std::numeric_limits<uint32_t>::max()); |
| 44 | } |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 45 | |
| 46 | // Allow std::move(). |
| 47 | TraceBlobView(TraceBlobView&&) noexcept = default; |
| 48 | TraceBlobView& operator=(TraceBlobView&&) = default; |
| 49 | |
| 50 | // Disable implicit copy. |
| 51 | TraceBlobView(const TraceBlobView&) = delete; |
| 52 | TraceBlobView& operator=(const TraceBlobView&) = delete; |
| 53 | |
Eric Seckler | 1edbe00 | 2019-12-16 18:08:57 +0000 | [diff] [blame] | 54 | TraceBlobView slice(size_t offset, size_t length) const { |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 55 | PERFETTO_DCHECK(offset + length <= offset_ + length_); |
| 56 | return TraceBlobView(shbuf_, offset, length); |
| 57 | } |
| 58 | |
| 59 | bool operator==(const TraceBlobView& rhs) const { |
| 60 | return (shbuf_ == rhs.shbuf_) && (offset_ == rhs.offset_) && |
| 61 | (length_ == rhs.length_); |
| 62 | } |
| 63 | bool operator!=(const TraceBlobView& rhs) const { return !(*this == rhs); } |
| 64 | |
| 65 | inline const uint8_t* data() const { return start() + offset_; } |
| 66 | |
| 67 | size_t offset_of(const uint8_t* data) const { |
Isabelle Taylor | de2bc3a | 2019-01-15 16:56:10 +0000 | [diff] [blame] | 68 | // When a field is size 0, data can be equal to start() + offset_ + length_. |
| 69 | PERFETTO_DCHECK(data >= start() && data <= (start() + offset_ + length_)); |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 70 | return static_cast<size_t>(data - start()); |
| 71 | } |
| 72 | |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 73 | size_t length() const { return length_; } |
Primiano Tucci | c167887 | 2019-03-20 11:30:54 +0000 | [diff] [blame] | 74 | size_t offset() const { return offset_; } |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 75 | |
| 76 | private: |
| 77 | // An equivalent to std::shared_ptr<uint8_t>, with the differnce that: |
| 78 | // - Supports array types, available for shared_ptr only in C++17. |
| 79 | // - Is not thread safe, which is not needed for our purposes. |
| 80 | class SharedBuf { |
| 81 | public: |
| 82 | explicit SharedBuf(std::unique_ptr<uint8_t[]> mem) { |
| 83 | rcbuf_ = new RefCountedBuf(std::move(mem)); |
| 84 | } |
| 85 | |
| 86 | SharedBuf(const SharedBuf& copy) : rcbuf_(copy.rcbuf_) { |
| 87 | PERFETTO_DCHECK(rcbuf_->refcount > 0); |
| 88 | rcbuf_->refcount++; |
| 89 | } |
| 90 | |
| 91 | ~SharedBuf() { |
| 92 | if (!rcbuf_) |
| 93 | return; |
| 94 | PERFETTO_DCHECK(rcbuf_->refcount > 0); |
| 95 | if (--rcbuf_->refcount == 0) { |
| 96 | RefCountedBuf* rcbuf = rcbuf_; |
| 97 | rcbuf_ = nullptr; |
| 98 | delete rcbuf; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | SharedBuf(SharedBuf&& other) noexcept { |
| 103 | rcbuf_ = other.rcbuf_; |
| 104 | other.rcbuf_ = nullptr; |
| 105 | } |
| 106 | |
| 107 | SharedBuf& operator=(SharedBuf&& other) { |
| 108 | if (this != &other) { |
| 109 | // A bit of a ugly but pragmatic pattern to implement move assignment. |
| 110 | // First invoke the distructor and then invoke the move constructor |
| 111 | // inline via placement-new. |
| 112 | this->~SharedBuf(); |
| 113 | new (this) SharedBuf(std::move(other)); |
| 114 | } |
| 115 | return *this; |
| 116 | } |
| 117 | |
| 118 | bool operator==(const SharedBuf& x) const { return x.rcbuf_ == rcbuf_; } |
| 119 | bool operator!=(const SharedBuf& x) const { return !(x == *this); } |
| 120 | const uint8_t* data() const { return rcbuf_->mem.get(); } |
| 121 | |
| 122 | private: |
| 123 | struct RefCountedBuf { |
| 124 | explicit RefCountedBuf(std::unique_ptr<uint8_t[]> buf) |
| 125 | : refcount(1), mem(std::move(buf)) {} |
| 126 | int refcount; |
| 127 | std::unique_ptr<uint8_t[]> mem; |
| 128 | }; |
| 129 | |
| 130 | RefCountedBuf* rcbuf_ = nullptr; |
| 131 | }; |
| 132 | |
| 133 | inline const uint8_t* start() const { return shbuf_.data(); } |
| 134 | |
| 135 | TraceBlobView(SharedBuf b, size_t o, size_t l) |
Primiano Tucci | 81d0a39 | 2018-09-04 15:15:37 +0100 | [diff] [blame] | 136 | : shbuf_(b), |
| 137 | offset_(static_cast<uint32_t>(o)), |
| 138 | length_(static_cast<uint32_t>(l)) {} |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 139 | |
| 140 | SharedBuf shbuf_; |
Primiano Tucci | 81d0a39 | 2018-09-04 15:15:37 +0100 | [diff] [blame] | 141 | uint32_t offset_; |
| 142 | uint32_t length_; // Measured from |offset_|, not from |data()|. |
Primiano Tucci | d933d91 | 2018-09-04 09:15:07 +0100 | [diff] [blame] | 143 | }; |
| 144 | |
| 145 | } // namespace trace_processor |
| 146 | } // namespace perfetto |
| 147 | |
Alexander Timin | 97d8785 | 2021-05-17 18:01:33 +0000 | [diff] [blame^] | 148 | #endif // SRC_TRACE_PROCESSOR_UTIL_TRACE_BLOB_VIEW_H_ |