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flutter / third_party / perfetto / f69cb9ae19b158e512a12e8fe9c945b5eb3c12d6 / . / src / shared_lib / pb_decoder.cc
blob: 02a12542d23e955f19791b6678f7fe808990a2fc [file] [log] [blame]
Daniele Di Proietto7451ea62023-01-09 11:31:16 +0000[diff] [blame]1/*
2 * Copyright (C) 2023 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#include "perfetto/public/abi/pb_decoder_abi.h"
18
19#include <limits>
20#include <type_traits>
21
22#include "perfetto/public/pb_utils.h"
23
24namespace {
25template <typename T>
26bool Uint64RepresentableIn(uint64_t val) {
27 return val <= std::numeric_limits<T>::max();
28}
29} // namespace
30
31struct PerfettoPbDecoderField PerfettoPbDecoderParseField(
32 struct PerfettoPbDecoder* decoder) {
33 struct PerfettoPbDecoderField field;
34 const uint8_t* read_ptr = decoder->read_ptr;
35 if (read_ptr >= decoder->end_ptr) {
36 field.status = PERFETTO_PB_DECODER_DONE;
37 return field;
38 }
39 field.status = PERFETTO_PB_DECODER_ERROR;
40 uint64_t tag;
41 const uint8_t* end_of_tag =
42 PerfettoPbParseVarInt(read_ptr, decoder->end_ptr, &tag);
43 if (end_of_tag == read_ptr) {
44 field.status = PERFETTO_PB_DECODER_ERROR;
45 return field;
46 }
47 read_ptr = end_of_tag;
48 constexpr uint8_t kFieldTypeNumBits = 3;
49
50 field.wire_type = tag & ((1 << kFieldTypeNumBits) - 1);
51 uint64_t id = tag >> kFieldTypeNumBits;
52 static_assert(std::is_same<uint32_t, decltype(field.id)>::value);
53 if (id > std::numeric_limits<uint32_t>::max()) {
54 field.status = PERFETTO_PB_DECODER_ERROR;
55 return field;
56 }
57 field.id = static_cast<uint32_t>(id);
58
59 switch (field.wire_type) {
60 case PERFETTO_PB_WIRE_TYPE_DELIMITED: {
61 uint64_t len;
62 const uint8_t* end_of_len =
63 PerfettoPbParseVarInt(read_ptr, decoder->end_ptr, &len);
64 if (end_of_len == read_ptr || !Uint64RepresentableIn<size_t>(len)) {
65 field.status = PERFETTO_PB_DECODER_ERROR;
66 return field;
67 }
68 read_ptr = end_of_len;
69 field.value.delimited.len = static_cast<size_t>(len);
70 field.value.delimited.start = read_ptr;
71 read_ptr += len;
72 if (read_ptr > decoder->end_ptr) {
73 field.status = PERFETTO_PB_DECODER_ERROR;
74 return field;
75 }
76 field.status = PERFETTO_PB_DECODER_OK;
77 decoder->read_ptr = read_ptr;
78 break;
79 }
80 case PERFETTO_PB_WIRE_TYPE_VARINT: {
81 uint64_t val;
82 const uint8_t* end_of_val =
83 PerfettoPbParseVarInt(read_ptr, decoder->end_ptr, &val);
84 if (end_of_val == read_ptr) {
85 field.status = PERFETTO_PB_DECODER_ERROR;
86 return field;
87 }
88 read_ptr = end_of_val;
89 field.value.integer64 = val;
90 field.status = PERFETTO_PB_DECODER_OK;
91 decoder->read_ptr = read_ptr;
92 break;
93 }
94 case PERFETTO_PB_WIRE_TYPE_FIXED32: {
95 const uint8_t* end_of_val = read_ptr + sizeof(uint32_t);
96 if (end_of_val > decoder->end_ptr) {
97 field.status = PERFETTO_PB_DECODER_ERROR;
98 return field;
99 }
100 // Little endian on the wire.
101 field.value.integer32 = read_ptr[0] |
102 (static_cast<uint32_t>(read_ptr[1]) << 8) |
103 (static_cast<uint32_t>(read_ptr[2]) << 16) |
104 (static_cast<uint32_t>(read_ptr[3]) << 24);
105 read_ptr = end_of_val;
106 decoder->read_ptr = read_ptr;
107 field.status = PERFETTO_PB_DECODER_OK;
108 break;
109 }
110 case PERFETTO_PB_WIRE_TYPE_FIXED64: {
111 const uint8_t* end_of_val = read_ptr + sizeof(uint64_t);
112 if (end_of_val > decoder->end_ptr) {
113 field.status = PERFETTO_PB_DECODER_ERROR;
114 return field;
115 }
116 // Little endian on the wire.
117 field.value.integer64 = read_ptr[0] |
118 (static_cast<uint64_t>(read_ptr[1]) << 8) |
119 (static_cast<uint64_t>(read_ptr[2]) << 16) |
120 (static_cast<uint64_t>(read_ptr[3]) << 24) |
121 (static_cast<uint64_t>(read_ptr[4]) << 32) |
122 (static_cast<uint64_t>(read_ptr[5]) << 40) |
123 (static_cast<uint64_t>(read_ptr[6]) << 48) |
124 (static_cast<uint64_t>(read_ptr[7]) << 56);
125 read_ptr = end_of_val;
126 decoder->read_ptr = read_ptr;
127 field.status = PERFETTO_PB_DECODER_OK;
128 break;
129 }
130 default:
131 field.status = PERFETTO_PB_DECODER_ERROR;
132 return field;
133 }
134 return field;
135}
136
137uint32_t PerfettoPbDecoderSkipField(struct PerfettoPbDecoder* decoder) {
138 const uint8_t* read_ptr = decoder->read_ptr;
139 if (read_ptr >= decoder->end_ptr) {
140 return PERFETTO_PB_DECODER_DONE;
141 }
142 uint64_t tag;
143 const uint8_t* end_of_tag =
144 PerfettoPbParseVarInt(decoder->read_ptr, decoder->end_ptr, &tag);
145 if (end_of_tag == read_ptr) {
146 return PERFETTO_PB_DECODER_ERROR;
147 }
148 read_ptr = end_of_tag;
149 constexpr uint8_t kFieldTypeNumBits = 3;
150
151 uint32_t wire_type = tag & ((1 << kFieldTypeNumBits) - 1);
152 switch (wire_type) {
153 case PERFETTO_PB_WIRE_TYPE_DELIMITED: {
154 uint64_t len;
155 const uint8_t* end_of_len =
156 PerfettoPbParseVarInt(read_ptr, decoder->end_ptr, &len);
157 if (end_of_len == read_ptr) {
158 return PERFETTO_PB_DECODER_ERROR;
159 }
160 read_ptr = end_of_len;
161 read_ptr += len;
162 if (read_ptr > decoder->end_ptr) {
163 return PERFETTO_PB_DECODER_ERROR;
164 }
165 decoder->read_ptr = read_ptr;
166 return PERFETTO_PB_DECODER_OK;
167 }
168 case PERFETTO_PB_WIRE_TYPE_VARINT: {
169 uint64_t val;
170 const uint8_t* end_of_val =
171 PerfettoPbParseVarInt(read_ptr, decoder->end_ptr, &val);
172 if (end_of_val == read_ptr) {
173 return PERFETTO_PB_DECODER_ERROR;
174 }
175 read_ptr = end_of_val;
176 decoder->read_ptr = read_ptr;
177 return PERFETTO_PB_DECODER_OK;
178 }
179 case PERFETTO_PB_WIRE_TYPE_FIXED32: {
180 const uint8_t* end_of_val = read_ptr + sizeof(uint32_t);
181 if (end_of_val > decoder->end_ptr) {
182 return PERFETTO_PB_DECODER_ERROR;
183 }
184 read_ptr = end_of_val;
185 decoder->read_ptr = read_ptr;
186 return PERFETTO_PB_DECODER_OK;
187 }
188 case PERFETTO_PB_WIRE_TYPE_FIXED64: {
189 const uint8_t* end_of_val = read_ptr + sizeof(uint64_t);
190 if (read_ptr > decoder->end_ptr) {
191 return PERFETTO_PB_DECODER_ERROR;
192 }
193 read_ptr = end_of_val;
194 decoder->read_ptr = read_ptr;
195 return PERFETTO_PB_DECODER_OK;
196 }
197 default:
198 break;
199 }
200 return PERFETTO_PB_DECODER_ERROR;
201}