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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // This file specifies a recursive data storage class called Value intended for | 5 // This file specifies a recursive data storage class called Value intended for |
6 // storing settings and other persistable data. | 6 // storing settings and other persistable data. |
7 // | 7 // |
8 // A Value represents something that can be stored in JSON or passed to/from | 8 // A Value represents something that can be stored in JSON or passed to/from |
9 // JavaScript. As such, it is NOT a generalized variant type, since only the | 9 // JavaScript. As such, it is NOT a generalized variant type, since only the |
10 // types supported by JavaScript/JSON are supported. | 10 // types supported by JavaScript/JSON are supported. |
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54 BOOLEAN, | 54 BOOLEAN, |
55 INTEGER, | 55 INTEGER, |
56 DOUBLE, | 56 DOUBLE, |
57 STRING, | 57 STRING, |
58 BINARY, | 58 BINARY, |
59 DICTIONARY, | 59 DICTIONARY, |
60 LIST | 60 LIST |
61 // Note: Do not add more types. See the file-level comment above for why. | 61 // Note: Do not add more types. See the file-level comment above for why. |
62 }; | 62 }; |
63 | 63 |
| 64 Value(); // A null value. |
| 65 |
64 virtual ~Value(); | 66 virtual ~Value(); |
65 | 67 |
66 static std::unique_ptr<Value> CreateNullValue(); | 68 static std::unique_ptr<Value> CreateNullValue(); |
67 | 69 |
68 // Returns the name for a given |type|. | 70 // Returns the name for a given |type|. |
69 static const char* GetTypeName(Type type); | 71 static const char* GetTypeName(Type type); |
70 | 72 |
71 // Returns the type of the value stored by the current Value object. | 73 // Returns the type of the value stored by the current Value object. |
72 // Each type will be implemented by only one subclass of Value, so it's | 74 // Each type will be implemented by only one subclass of Value, so it's |
73 // safe to use the Type to determine whether you can cast from | 75 // safe to use the Type to determine whether you can cast from |
74 // Value* to (Implementing Class)*. Also, a Value object never changes | 76 // Value* to (Implementing Class)*. Also, a Value object never changes |
75 // its type after construction. | 77 // its type after construction. |
76 Type GetType() const { return type_; } | 78 Type GetType() const { return type_; } // DEPRECATED, use type(). |
| 79 Type type() const { return type_; } |
77 | 80 |
78 // Returns true if the current object represents a given type. | 81 // Returns true if the current object represents a given type. |
79 bool IsType(Type type) const { return type == type_; } | 82 bool IsType(Type type) const { return type == type_; } |
| 83 bool is_bool() const { return type() == Type::BOOLEAN; } |
| 84 bool is_int() const { return type() == Type::INTEGER; } |
| 85 bool is_double() const { return type() == Type::DOUBLE; } |
| 86 bool is_string() const { return type() == Type::STRING; } |
| 87 bool is_blob() const { return type() == Type::BINARY; } |
| 88 bool is_dict() const { return type() == Type::DICTIONARY; } |
| 89 bool is_list() const { return type() == Type::LIST; } |
| 90 |
| 91 // These will all fatally assert if the type doesn't match. |
| 92 bool GetBool() const; |
| 93 int GetInt() const; |
| 94 double GetDouble() const; // Implicitly converts from int if necessary. |
80 | 95 |
81 // These methods allow the convenient retrieval of the contents of the Value. | 96 // These methods allow the convenient retrieval of the contents of the Value. |
82 // If the current object can be converted into the given type, the value is | 97 // If the current object can be converted into the given type, the value is |
83 // returned through the |out_value| parameter and true is returned; | 98 // returned through the |out_value| parameter and true is returned; |
84 // otherwise, false is returned and |out_value| is unchanged. | 99 // otherwise, false is returned and |out_value| is unchanged. |
85 virtual bool GetAsBoolean(bool* out_value) const; | 100 virtual bool GetAsBoolean(bool* out_value) const; |
86 virtual bool GetAsInteger(int* out_value) const; | 101 virtual bool GetAsInteger(int* out_value) const; |
87 virtual bool GetAsDouble(double* out_value) const; | 102 virtual bool GetAsDouble(double* out_value) const; |
88 virtual bool GetAsString(std::string* out_value) const; | 103 virtual bool GetAsString(std::string* out_value) const; |
89 virtual bool GetAsString(string16* out_value) const; | 104 virtual bool GetAsString(string16* out_value) const; |
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111 virtual bool Equals(const Value* other) const; | 126 virtual bool Equals(const Value* other) const; |
112 | 127 |
113 // Compares if two Value objects have equal contents. Can handle NULLs. | 128 // Compares if two Value objects have equal contents. Can handle NULLs. |
114 // NULLs are considered equal but different from Value::CreateNullValue(). | 129 // NULLs are considered equal but different from Value::CreateNullValue(). |
115 static bool Equals(const Value* a, const Value* b); | 130 static bool Equals(const Value* a, const Value* b); |
116 | 131 |
117 protected: | 132 protected: |
118 // These aren't safe for end-users, but they are useful for subclasses. | 133 // These aren't safe for end-users, but they are useful for subclasses. |
119 explicit Value(Type type); | 134 explicit Value(Type type); |
120 Value(const Value& that); | 135 Value(const Value& that); |
| 136 Value(Value&& that); |
121 Value& operator=(const Value& that); | 137 Value& operator=(const Value& that); |
| 138 Value& operator=(Value&& that); |
| 139 |
| 140 // TODO(brettw) move to public when FundamentalValue is gone. |
| 141 explicit Value(bool in_bool); |
| 142 explicit Value(int in_int); |
| 143 explicit Value(double in_double); |
122 | 144 |
123 private: | 145 private: |
| 146 void InternalCopyFrom(const Value& that); |
| 147 |
124 Type type_; | 148 Type type_; |
| 149 |
| 150 union { |
| 151 bool bool_value_; |
| 152 int int_value_; |
| 153 double double_value_; |
| 154 }; |
125 }; | 155 }; |
126 | 156 |
127 // FundamentalValue represents the simple fundamental types of values. | 157 // FundamentalValue represents the simple fundamental types of values. |
| 158 // TODO(brettw) remove when callers are updated to use raw Value. |
128 class BASE_EXPORT FundamentalValue : public Value { | 159 class BASE_EXPORT FundamentalValue : public Value { |
129 public: | 160 public: |
130 explicit FundamentalValue(bool in_value); | 161 explicit FundamentalValue(bool in_value); |
131 explicit FundamentalValue(int in_value); | 162 explicit FundamentalValue(int in_value); |
132 explicit FundamentalValue(double in_value); | 163 explicit FundamentalValue(double in_value); |
133 ~FundamentalValue() override; | 164 ~FundamentalValue() override; |
134 | |
135 // Overridden from Value: | |
136 bool GetAsBoolean(bool* out_value) const override; | |
137 bool GetAsInteger(int* out_value) const override; | |
138 // Values of both type Type::INTEGER and Type::DOUBLE can be obtained as | |
139 // doubles. | |
140 bool GetAsDouble(double* out_value) const override; | |
141 FundamentalValue* DeepCopy() const override; | |
142 bool Equals(const Value* other) const override; | |
143 | |
144 private: | |
145 union { | |
146 bool boolean_value_; | |
147 int integer_value_; | |
148 double double_value_; | |
149 }; | |
150 }; | 165 }; |
151 | 166 |
152 class BASE_EXPORT StringValue : public Value { | 167 class BASE_EXPORT StringValue : public Value { |
153 public: | 168 public: |
154 // Initializes a StringValue with a UTF-8 narrow character string. | 169 // Initializes a StringValue with a UTF-8 narrow character string. |
155 explicit StringValue(StringPiece in_value); | 170 explicit StringValue(StringPiece in_value); |
156 | 171 |
157 // Initializes a StringValue with a string16. | 172 // Initializes a StringValue with a string16. |
158 explicit StringValue(const string16& in_value); | 173 explicit StringValue(const string16& in_value); |
159 | 174 |
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564 return out << static_cast<const Value&>(value); | 579 return out << static_cast<const Value&>(value); |
565 } | 580 } |
566 | 581 |
567 // Stream operator so that enum class Types can be used in log statements. | 582 // Stream operator so that enum class Types can be used in log statements. |
568 BASE_EXPORT std::ostream& operator<<(std::ostream& out, | 583 BASE_EXPORT std::ostream& operator<<(std::ostream& out, |
569 const Value::Type& type); | 584 const Value::Type& type); |
570 | 585 |
571 } // namespace base | 586 } // namespace base |
572 | 587 |
573 #endif // BASE_VALUES_H_ | 588 #endif // BASE_VALUES_H_ |
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