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1 /*
2  * Copyright (C) 2011 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_RUNTIME_MIRROR_STRING_H_
18 #define ART_RUNTIME_MIRROR_STRING_H_
19 
20 #include "gc_root.h"
21 #include "gc/allocator_type.h"
22 #include "object.h"
23 #include "object_callbacks.h"
24 
25 namespace art {
26 
27 template<class T> class Handle;
28 struct StringOffsets;
29 class StringPiece;
30 
31 namespace mirror {
32 
33 // C++ mirror of java.lang.String
34 class MANAGED String FINAL : public Object {
35  public:
36   // Size of java.lang.String.class.
37   static uint32_t ClassSize(size_t pointer_size);
38 
39   // Size of an instance of java.lang.String not including its value array.
InstanceSize()40   static constexpr uint32_t InstanceSize() {
41     return sizeof(String);
42   }
43 
CountOffset()44   static MemberOffset CountOffset() {
45     return OFFSET_OF_OBJECT_MEMBER(String, count_);
46   }
47 
ValueOffset()48   static MemberOffset ValueOffset() {
49     return OFFSET_OF_OBJECT_MEMBER(String, value_);
50   }
51 
GetValue()52   uint16_t* GetValue() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
53     return &value_[0];
54   }
55 
56   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
57   size_t SizeOf() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
58 
59   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
GetLength()60   int32_t GetLength() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
61     return GetField32<kVerifyFlags>(OFFSET_OF_OBJECT_MEMBER(String, count_));
62   }
63 
SetCount(int32_t new_count)64   void SetCount(int32_t new_count) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
65     // Count is invariant so use non-transactional mode. Also disable check as we may run inside
66     // a transaction.
67     DCHECK_LE(0, new_count);
68     SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(String, count_), new_count);
69   }
70 
71   int32_t GetHashCode() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
72 
73   // Computes, stores, and returns the hash code.
74   int32_t ComputeHashCode() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
75 
76   int32_t GetUtfLength() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
77 
78   uint16_t CharAt(int32_t index) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
79 
80   void SetCharAt(int32_t index, uint16_t c) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
81 
82   String* Intern() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
83 
84   template <bool kIsInstrumented, typename PreFenceVisitor>
85   ALWAYS_INLINE static String* Alloc(Thread* self, int32_t utf16_length,
86                                      gc::AllocatorType allocator_type,
87                                      const PreFenceVisitor& pre_fence_visitor)
88       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
89 
90   template <bool kIsInstrumented>
91   ALWAYS_INLINE static String* AllocFromByteArray(Thread* self, int32_t byte_length,
92                                                   Handle<ByteArray> array, int32_t offset,
93                                                   int32_t high_byte,
94                                                   gc::AllocatorType allocator_type)
95       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
96 
97   template <bool kIsInstrumented>
98   ALWAYS_INLINE static String* AllocFromCharArray(Thread* self, int32_t array_length,
99                                                   Handle<CharArray> array, int32_t offset,
100                                                   gc::AllocatorType allocator_type)
101       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
102 
103   template <bool kIsInstrumented>
104   ALWAYS_INLINE static String* AllocFromString(Thread* self, int32_t string_length,
105                                                Handle<String> string, int32_t offset,
106                                                gc::AllocatorType allocator_type)
107       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
108 
109   static String* AllocFromStrings(Thread* self, Handle<String> string, Handle<String> string2)
110       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
111 
112   static String* AllocFromUtf16(Thread* self, int32_t utf16_length, const uint16_t* utf16_data_in)
113       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
114 
115   static String* AllocFromModifiedUtf8(Thread* self, const char* utf)
116       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
117 
118   static String* AllocFromModifiedUtf8(Thread* self, int32_t utf16_length, const char* utf8_data_in)
119       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
120 
121   // TODO: This is only used in the interpreter to compare against
122   // entries from a dex files constant pool (ArtField names). Should
123   // we unify this with Equals(const StringPiece&); ?
124   bool Equals(const char* modified_utf8) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
125 
126   // TODO: This is only used to compare DexCache.location with
127   // a dex_file's location (which is an std::string). Do we really
128   // need this in mirror::String just for that one usage ?
129   bool Equals(const StringPiece& modified_utf8)
130       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
131 
132   bool Equals(String* that) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
133 
134   // Compare UTF-16 code point values not in a locale-sensitive manner
135   int Compare(int32_t utf16_length, const char* utf8_data_in);
136 
137   // TODO: do we need this overload? give it a more intention-revealing name.
138   bool Equals(const uint16_t* that_chars, int32_t that_offset,
139               int32_t that_length)
140       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
141 
142   // Create a modified UTF-8 encoded std::string from a java/lang/String object.
143   std::string ToModifiedUtf8() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
144 
145   int32_t FastIndexOf(int32_t ch, int32_t start) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
146 
147   int32_t CompareTo(String* other) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
148 
149   CharArray* ToCharArray(Thread* self) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
150 
151   void GetChars(int32_t start, int32_t end, Handle<CharArray> array, int32_t index)
152       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
153 
GetJavaLangString()154   static Class* GetJavaLangString() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
155     DCHECK(!java_lang_String_.IsNull());
156     return java_lang_String_.Read();
157   }
158 
159   static void SetClass(Class* java_lang_String);
160   static void ResetClass();
161   static void VisitRoots(RootVisitor* visitor)
162       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
163 
164  private:
SetHashCode(int32_t new_hash_code)165   void SetHashCode(int32_t new_hash_code) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
166     // Hash code is invariant so use non-transactional mode. Also disable check as we may run inside
167     // a transaction.
168     DCHECK_EQ(0, GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_)));
169     SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), new_hash_code);
170   }
171 
172   // Field order required by test "ValidateFieldOrderOfJavaCppUnionClasses".
173   int32_t count_;
174 
175   uint32_t hash_code_;
176 
177   uint16_t value_[0];
178 
179   static GcRoot<Class> java_lang_String_;
180 
181   friend struct art::StringOffsets;  // for verifying offset information
182   ART_FRIEND_TEST(ObjectTest, StringLength);  // for SetOffset and SetCount
183 
184   DISALLOW_IMPLICIT_CONSTRUCTORS(String);
185 };
186 
187 }  // namespace mirror
188 }  // namespace art
189 
190 #endif  // ART_RUNTIME_MIRROR_STRING_H_
191