1 /**
2  * Copyright (c) 2021-2022 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #include "class_data_accessor.h"
17 
18 #include "utils/leb128.h"
19 #include "utils/utf.h"
20 
21 namespace panda::panda_file {
22 
ClassDataAccessor(const File &panda_file, File::EntityId class_id)23 ClassDataAccessor::ClassDataAccessor(const File &panda_file, File::EntityId class_id)
24     : panda_file_(panda_file), class_id_(class_id), name_(), num_fields_(0), num_methods_(0), num_ifaces_(0), size_(0)
25 {
26     ASSERT(!panda_file.IsExternal(class_id));
27     auto sp = panda_file_.GetSpanFromId(class_id_);
28     name_.utf16_length = helpers::ReadULeb128(&sp);
29     name_.data = sp.data();
30 
31     size_t size = utf::Mutf8Size(name_.data) + 1;  // + 1 for null byte
32     panda_file_.ThrowIfWithCheck(sp.Size() < size, File::INVALID_FILE_OFFSET, File::CLASS_DATA_ACCESSOR);
33     sp = sp.SubSpan(size);
34 
35     super_class_off_ = helpers::Read<ID_SIZE>(&sp);
36 
37     access_flags_ = helpers::ReadULeb128(&sp);
38     num_fields_ = helpers::ReadULeb128(&sp);
39     num_methods_ = helpers::ReadULeb128(&sp);
40 
41     panda_file_.ThrowIfWithCheck(sp.Size() == 0U, File::INVALID_FILE_OFFSET, File::CLASS_DATA_ACCESSOR);
42     auto tag = static_cast<ClassTag>(sp[0]);
43 
44     while (tag != ClassTag::NOTHING && tag < ClassTag::SOURCE_LANG) {
45         panda_file_.ThrowIfWithCheck(sp.Size() == 0U, File::INVALID_FILE_OFFSET, File::CLASS_DATA_ACCESSOR);
46         sp = sp.SubSpan(1);
47 
48         if (tag == ClassTag::INTERFACES) {
49             num_ifaces_ = helpers::ReadULeb128(&sp);
50             ifaces_offsets_sp_ = sp;
51             size_t scale = IDX_SIZE * num_ifaces_;
52             panda_file_.ThrowIfWithCheck(sp.Size() < scale, File::INVALID_FILE_OFFSET, File::CLASS_DATA_ACCESSOR);
53             sp = sp.SubSpan(scale);
54         }
55 
56         panda_file_.ThrowIfWithCheck(sp.Size() == 0U, File::INVALID_FILE_OFFSET, File::CLASS_DATA_ACCESSOR);
57         tag = static_cast<ClassTag>(sp[0]);
58     }
59 
60     source_lang_sp_ = sp;
61 
62     if (tag == ClassTag::NOTHING) {
63         annotations_sp_ = sp;
64         source_file_sp_ = sp;
65         panda_file_.ThrowIfWithCheck(sp.Size() < TAG_SIZE, File::INVALID_FILE_OFFSET, File::CLASS_DATA_ACCESSOR);
66         fields_sp_ = sp.SubSpan(TAG_SIZE);  // skip NOTHING tag
67     }
68 }
69 
70 }  // namespace panda::panda_file
71