Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 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 | #include "protozero/protozero_message.h" |
| 18 | |
| 19 | #include <type_traits> |
| 20 | |
Primiano Tucci | d7d1be0 | 2017-10-30 17:41:34 +0000 | [diff] [blame] | 21 | #include "base/logging.h" |
Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 22 | |
| 23 | #if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__ |
| 24 | // The memcpy() for float and double below needs to be adjusted if we want to |
| 25 | // support big endian CPUs. There doesn't seem to be a compelling need today. |
| 26 | #error Unimplemented for big endian archs. |
| 27 | #endif |
| 28 | |
| 29 | namespace protozero { |
| 30 | |
| 31 | // static |
| 32 | constexpr uint32_t ProtoZeroMessage::kMaxNestingDepth; |
| 33 | |
| 34 | // Do NOT put any code in the constructor or use default initialization. |
| 35 | // Use the Reset() method below instead. See the header for the reason why. |
| 36 | |
| 37 | // This method is called to initialize both root and nested messages. |
| 38 | void ProtoZeroMessage::Reset(ScatteredStreamWriter* stream_writer) { |
| 39 | // Older versions of libstdcxx don't have is_trivially_constructible. |
| 40 | #if !defined(__GLIBCXX__) || __GLIBCXX__ >= 20170516 |
| 41 | static_assert(std::is_trivially_constructible<ProtoZeroMessage>::value, |
| 42 | "ProtoZeroMessage must be trivially constructible"); |
| 43 | #endif |
| 44 | |
| 45 | static_assert(std::is_trivially_destructible<ProtoZeroMessage>::value, |
| 46 | "ProtoZeroMessage must be trivially destructible"); |
| 47 | |
| 48 | static_assert( |
| 49 | sizeof(ProtoZeroMessage::nested_messages_arena_) >= |
| 50 | kMaxNestingDepth * (sizeof(ProtoZeroMessage) - |
| 51 | sizeof(ProtoZeroMessage::nested_messages_arena_)), |
| 52 | "ProtoZeroMessage::nested_messages_arena_ is too small"); |
| 53 | |
| 54 | stream_writer_ = stream_writer; |
| 55 | size_ = 0; |
| 56 | size_field_.reset(); |
Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 57 | nested_message_ = nullptr; |
| 58 | nesting_depth_ = 0; |
| 59 | #if PROTOZERO_ENABLE_HANDLE_DEBUGGING() |
| 60 | sealed_ = false; |
| 61 | handle_ = nullptr; |
| 62 | #endif |
| 63 | } |
| 64 | |
| 65 | void ProtoZeroMessage::AppendString(uint32_t field_id, const char* str) { |
| 66 | AppendBytes(field_id, str, strlen(str)); |
| 67 | } |
| 68 | |
| 69 | void ProtoZeroMessage::AppendBytes(uint32_t field_id, |
| 70 | const void* src, |
| 71 | size_t size) { |
| 72 | if (nested_message_) |
| 73 | EndNestedMessage(); |
| 74 | |
Primiano Tucci | d7d1be0 | 2017-10-30 17:41:34 +0000 | [diff] [blame] | 75 | PERFETTO_DCHECK(size < proto_utils::kMaxMessageLength); |
Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 76 | // Write the proto preamble (field id, type and length of the field). |
| 77 | uint8_t buffer[proto_utils::kMaxSimpleFieldEncodedSize]; |
| 78 | uint8_t* pos = buffer; |
| 79 | pos = proto_utils::WriteVarInt(proto_utils::MakeTagLengthDelimited(field_id), |
| 80 | pos); |
| 81 | pos = proto_utils::WriteVarInt(static_cast<uint32_t>(size), pos); |
| 82 | WriteToStream(buffer, pos); |
| 83 | |
| 84 | const uint8_t* src_u8 = reinterpret_cast<const uint8_t*>(src); |
| 85 | WriteToStream(src_u8, src_u8 + size); |
| 86 | } |
| 87 | |
| 88 | size_t ProtoZeroMessage::Finalize() { |
| 89 | if (nested_message_) |
| 90 | EndNestedMessage(); |
| 91 | |
| 92 | // Write the length of the nested message a posteriori, using a leading-zero |
| 93 | // redundant varint encoding. |
| 94 | if (size_field_.is_valid()) { |
| 95 | #if PROTOZERO_ENABLE_HANDLE_DEBUGGING() |
Primiano Tucci | d7d1be0 | 2017-10-30 17:41:34 +0000 | [diff] [blame] | 96 | PERFETTO_DCHECK(!sealed_); |
Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 97 | #endif |
Primiano Tucci | d7d1be0 | 2017-10-30 17:41:34 +0000 | [diff] [blame] | 98 | PERFETTO_DCHECK(size_ < proto_utils::kMaxMessageLength); |
| 99 | PERFETTO_DCHECK(proto_utils::kMessageLengthFieldSize == size_field_.size()); |
Primiano Tucci | 25aff4e | 2017-11-23 12:18:52 +0000 | [diff] [blame] | 100 | proto_utils::WriteRedundantVarInt(static_cast<uint32_t>(size_), |
| 101 | size_field_.begin); |
Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 102 | size_field_.reset(); |
| 103 | } |
| 104 | |
| 105 | #if PROTOZERO_ENABLE_HANDLE_DEBUGGING() |
| 106 | sealed_ = true; |
| 107 | if (handle_) |
| 108 | handle_->reset_message(); |
| 109 | #endif |
| 110 | |
| 111 | return size_; |
| 112 | } |
| 113 | |
| 114 | void ProtoZeroMessage::BeginNestedMessageInternal(uint32_t field_id, |
| 115 | ProtoZeroMessage* message) { |
| 116 | if (nested_message_) |
| 117 | EndNestedMessage(); |
| 118 | |
| 119 | // Write the proto preamble for the nested message. |
| 120 | uint8_t data[proto_utils::kMaxTagEncodedSize]; |
| 121 | uint8_t* data_end = proto_utils::WriteVarInt( |
| 122 | proto_utils::MakeTagLengthDelimited(field_id), data); |
| 123 | WriteToStream(data, data_end); |
| 124 | |
| 125 | message->Reset(stream_writer_); |
Primiano Tucci | d7d1be0 | 2017-10-30 17:41:34 +0000 | [diff] [blame] | 126 | PERFETTO_CHECK(nesting_depth_ < kMaxNestingDepth); |
Primiano Tucci | 2a29ac7 | 2017-10-24 17:47:19 +0100 | [diff] [blame] | 127 | message->nesting_depth_ = nesting_depth_ + 1; |
| 128 | |
| 129 | // The length of the nested message cannot be known upfront. So right now |
| 130 | // just reserve the bytes to encode the size after the nested message is done. |
| 131 | message->set_size_field( |
| 132 | stream_writer_->ReserveBytes(proto_utils::kMessageLengthFieldSize)); |
| 133 | size_ += proto_utils::kMessageLengthFieldSize; |
| 134 | nested_message_ = message; |
| 135 | } |
| 136 | |
| 137 | void ProtoZeroMessage::EndNestedMessage() { |
| 138 | size_ += nested_message_->Finalize(); |
| 139 | nested_message_ = nullptr; |
| 140 | } |
| 141 | |
| 142 | } // namespace protozero |