1 /*
2  * Copyright (C) 2013 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 #ifndef ART_LIBDEXFILE_DEX_METHOD_REFERENCE_H_
18 #define ART_LIBDEXFILE_DEX_METHOD_REFERENCE_H_
19 
20 #include <stdint.h>
21 #include <string>
22 #include "dex/dex_file.h"
23 #include "dex/dex_file_reference.h"
24 
25 namespace art {
26 
27 // A method is uniquely located by its DexFile and the method_ids_ table index into that DexFile
28 class MethodReference : public DexFileReference {
29  public:
MethodReference(const DexFile * file,uint32_t index)30   MethodReference(const DexFile* file, uint32_t index) : DexFileReference(file, index) {}
31   std::string PrettyMethod(bool with_signature = true) const {
32     return dex_file->PrettyMethod(index, with_signature);
33   }
GetMethodId()34   const dex::MethodId& GetMethodId() const {
35     return dex_file->GetMethodId(index);
36   }
37 };
38 
39 // Compare the actual referenced method signatures. Used for method reference deduplication.
40 struct MethodReferenceValueComparator {
operatorMethodReferenceValueComparator41   bool operator()(MethodReference mr1, MethodReference mr2) const {
42     if (mr1.dex_file == mr2.dex_file) {
43       DCHECK_EQ(mr1.index < mr2.index, SlowCompare(mr1, mr2));
44       return mr1.index < mr2.index;
45     } else {
46       return SlowCompare(mr1, mr2);
47     }
48   }
49 
SlowCompareMethodReferenceValueComparator50   bool SlowCompare(MethodReference mr1, MethodReference mr2) const {
51     // The order is the same as for method ids in a single dex file.
52     // Compare the class descriptors first.
53     const dex::MethodId& mid1 = mr1.GetMethodId();
54     const dex::MethodId& mid2 = mr2.GetMethodId();
55     int descriptor_diff = strcmp(mr1.dex_file->StringByTypeIdx(mid1.class_idx_),
56                                  mr2.dex_file->StringByTypeIdx(mid2.class_idx_));
57     if (descriptor_diff != 0) {
58       return descriptor_diff < 0;
59     }
60     // Compare names second.
61     int name_diff = strcmp(mr1.dex_file->GetMethodName(mid1), mr2.dex_file->GetMethodName(mid2));
62     if (name_diff != 0) {
63       return name_diff < 0;
64     }
65     // And then compare proto ids, starting with return type comparison.
66     const dex::ProtoId& prid1 = mr1.dex_file->GetProtoId(mid1.proto_idx_);
67     const dex::ProtoId& prid2 = mr2.dex_file->GetProtoId(mid2.proto_idx_);
68     int return_type_diff = strcmp(mr1.dex_file->StringByTypeIdx(prid1.return_type_idx_),
69                                   mr2.dex_file->StringByTypeIdx(prid2.return_type_idx_));
70     if (return_type_diff != 0) {
71       return return_type_diff < 0;
72     }
73     // And finishing with lexicographical parameter comparison.
74     const dex::TypeList* params1 = mr1.dex_file->GetProtoParameters(prid1);
75     size_t param1_size = (params1 != nullptr) ? params1->Size() : 0u;
76     const dex::TypeList* params2 = mr2.dex_file->GetProtoParameters(prid2);
77     size_t param2_size = (params2 != nullptr) ? params2->Size() : 0u;
78     for (size_t i = 0, num = std::min(param1_size, param2_size); i != num; ++i) {
79       int param_diff = strcmp(mr1.dex_file->StringByTypeIdx(params1->GetTypeItem(i).type_idx_),
80                               mr2.dex_file->StringByTypeIdx(params2->GetTypeItem(i).type_idx_));
81       if (param_diff != 0) {
82         return param_diff < 0;
83       }
84     }
85     return param1_size < param2_size;
86   }
87 };
88 
89 }  // namespace art
90 
91 #endif  // ART_LIBDEXFILE_DEX_METHOD_REFERENCE_H_
92