1 /*
2 * Copyright 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 #include "fields/payload_field.h"
18 #include "util.h"
19
20 const std::string PayloadField::kFieldType = "PayloadField";
21
PayloadField(std::string modifier,ParseLocation loc)22 PayloadField::PayloadField(std::string modifier, ParseLocation loc)
23 : PacketField("payload", loc), size_field_(nullptr), size_modifier_(modifier) {}
24
SetSizeField(const SizeField * size_field)25 void PayloadField::SetSizeField(const SizeField* size_field) {
26 if (size_field_ != nullptr) {
27 ERROR(this, size_field_, size_field) << "The size field for the payload has already been assigned.";
28 }
29
30 size_field_ = size_field;
31 }
32
GetFieldType() const33 const std::string& PayloadField::GetFieldType() const {
34 return PayloadField::kFieldType;
35 }
36
GetSize() const37 Size PayloadField::GetSize() const {
38 if (size_field_ == nullptr) {
39 if (!size_modifier_.empty()) {
40 ERROR(this) << "Missing size field for payload with size modifier.";
41 }
42 return Size();
43 }
44
45 std::string dynamic_size = "(Get" + util::UnderscoreToCamelCase(size_field_->GetName()) + "() * 8)";
46 if (!size_modifier_.empty()) {
47 dynamic_size += "- (" + size_modifier_.substr(1) + " * 8)";
48 }
49
50 return dynamic_size;
51 }
52
GetDataType() const53 std::string PayloadField::GetDataType() const {
54 return "PacketView";
55 }
56
GenExtractor(std::ostream &,int,bool) const57 void PayloadField::GenExtractor(std::ostream&, int, bool) const {
58 ERROR(this) << __func__ << " should never be called. ";
59 }
60
GetGetterFunctionName() const61 std::string PayloadField::GetGetterFunctionName() const {
62 return "GetPayload";
63 }
64
GenGetter(std::ostream & s,Size start_offset,Size end_offset) const65 void PayloadField::GenGetter(std::ostream& s, Size start_offset, Size end_offset) const {
66 s << "PacketView<kLittleEndian> " << GetGetterFunctionName() << "() const {";
67 s << "ASSERT(was_validated_);";
68 s << "size_t end_index = size();";
69 s << "auto to_bound = begin();";
70 GenBounds(s, start_offset, end_offset, GetSize());
71 s << "return GetLittleEndianSubview(field_begin, field_end);";
72 s << "}\n\n";
73 }
74
GetBuilderParameterType() const75 std::string PayloadField::GetBuilderParameterType() const {
76 return "std::unique_ptr<BasePacketBuilder>";
77 }
78
BuilderParameterMustBeMoved() const79 bool PayloadField::BuilderParameterMustBeMoved() const {
80 return true;
81 }
82
GenBuilderParameterFromView(std::ostream & s) const83 void PayloadField::GenBuilderParameterFromView(std::ostream& s) const {
84 s << "std::make_unique<RawBuilder>(std::vector<uint8_t>(view.GetPayload().begin(), view.GetPayload().end()))";
85 }
86
HasParameterValidator() const87 bool PayloadField::HasParameterValidator() const {
88 return false;
89 }
90
GenParameterValidator(std::ostream &) const91 void PayloadField::GenParameterValidator(std::ostream&) const {
92 // There is no validation needed for a payload
93 }
94
GenInserter(std::ostream &) const95 void PayloadField::GenInserter(std::ostream&) const {
96 ERROR() << __func__ << " Should never be called.";
97 }
98
GenValidator(std::ostream &) const99 void PayloadField::GenValidator(std::ostream&) const {
100 // Do nothing
101 }
102
GenStringRepresentation(std::ostream & s,std::string) const103 void PayloadField::GenStringRepresentation(std::ostream& s, std::string) const {
104 // TODO: we should parse the child packets
105 s << "\"PAYLOAD[]\"";
106 }
107
GetRustDataType() const108 std::string PayloadField::GetRustDataType() const {
109 return "Vec::<u8>";
110 }
111
GenBoundsCheck(std::ostream & s,Size start_offset,Size,std::string parent_name) const112 void PayloadField::GenBoundsCheck(std::ostream& s, Size start_offset, Size, std::string parent_name) const {
113 if (size_field_ != nullptr) {
114 s << "let want_ = " << start_offset.bytes() << " + (" << size_field_->GetName() << " as usize)";
115 if (!size_modifier_.empty()) {
116 s << " - " << size_modifier_.substr(1);
117 }
118 s << ";";
119 s << "if bytes.len() < want_ {";
120 s << " return Err(Error::InvalidLengthError{";
121 s << " obj: \"" << parent_name << "\".to_string(),";
122 s << " field: \"" << GetName() << "\".to_string(),";
123 s << " wanted: want_,";
124 s << " got: bytes.len()});";
125 s << "}";
126 if (!size_modifier_.empty()) {
127 s << "if (" << size_field_->GetName() << " as usize) < " << size_modifier_.substr(1) << " {";
128 s << " return Err(Error::ImpossibleStructError);";
129 s << "}";
130 }
131 }
132 }
133
GenRustGetter(std::ostream & s,Size start_offset,Size,std::string) const134 void PayloadField::GenRustGetter(std::ostream& s, Size start_offset, Size, std::string) const {
135 s << "let " << GetName() << ": " << GetRustDataType() << " = ";
136 if (size_field_ == nullptr) {
137 s << "bytes[" << start_offset.bytes() << "..].into();";
138 } else {
139 s << "bytes[" << start_offset.bytes() << "..(";
140 s << start_offset.bytes() << " + " << size_field_->GetName() << " as usize)].into();";
141 }
142 }
143
GenRustWriter(std::ostream &,Size,Size) const144 void PayloadField::GenRustWriter(std::ostream&, Size, Size) const {}
145