| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // This file specifies a recursive data storage class called Value intended for |
| // storing settings and other persistable data. |
| // |
| // A Value represents something that can be stored in JSON or passed to/from |
| // JavaScript. As such, it is NOT a generalized variant type, since only the |
| // types supported by JavaScript/JSON are supported. |
| // |
| // IN PARTICULAR this means that there is no support for int64_t or unsigned |
| // numbers. Writing JSON with such types would violate the spec. If you need |
| // something like this, either use a double or make a string value containing |
| // the number you want. |
| |
| #ifndef BASE_VALUES_H_ |
| #define BASE_VALUES_H_ |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #include <iosfwd> |
| #include <map> |
| #include <memory> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "base/base_export.h" |
| #include "base/compiler_specific.h" |
| #include "base/macros.h" |
| #include "base/strings/string_piece.h" |
| |
| namespace base { |
| |
| class BinaryValue; |
| class DictionaryValue; |
| class FundamentalValue; |
| class ListValue; |
| class StringValue; |
| class Value; |
| |
| // The Value class is the base class for Values. A Value can be instantiated |
| // via the Create*Value() factory methods, or by directly creating instances of |
| // the subclasses. |
| // |
| // See the file-level comment above for more information. |
| class BASE_EXPORT Value { |
| public: |
| enum Type { |
| TYPE_NULL = 0, |
| TYPE_BOOLEAN, |
| TYPE_INTEGER, |
| TYPE_DOUBLE, |
| TYPE_STRING, |
| TYPE_BINARY, |
| TYPE_DICTIONARY, |
| TYPE_LIST |
| // Note: Do not add more types. See the file-level comment above for why. |
| }; |
| |
| virtual ~Value(); |
| |
| static std::unique_ptr<Value> CreateNullValue(); |
| |
| // Returns the type of the value stored by the current Value object. |
| // Each type will be implemented by only one subclass of Value, so it's |
| // safe to use the Type to determine whether you can cast from |
| // Value* to (Implementing Class)*. Also, a Value object never changes |
| // its type after construction. |
| Type GetType() const { return type_; } |
| |
| // Returns true if the current object represents a given type. |
| bool IsType(Type type) const { return type == type_; } |
| |
| // These methods allow the convenient retrieval of the contents of the Value. |
| // If the current object can be converted into the given type, the value is |
| // returned through the |out_value| parameter and true is returned; |
| // otherwise, false is returned and |out_value| is unchanged. |
| virtual bool GetAsBoolean(bool* out_value) const; |
| virtual bool GetAsInteger(int* out_value) const; |
| virtual bool GetAsDouble(double* out_value) const; |
| virtual bool GetAsString(std::string* out_value) const; |
| virtual bool GetAsString(const StringValue** out_value) const; |
| virtual bool GetAsBinary(const BinaryValue** out_value) const; |
| virtual bool GetAsList(ListValue** out_value); |
| virtual bool GetAsList(const ListValue** out_value) const; |
| virtual bool GetAsDictionary(DictionaryValue** out_value); |
| virtual bool GetAsDictionary(const DictionaryValue** out_value) const; |
| // Note: Do not add more types. See the file-level comment above for why. |
| |
| // This creates a deep copy of the entire Value tree, and returns a pointer |
| // to the copy. The caller gets ownership of the copy, of course. |
| // |
| // Subclasses return their own type directly in their overrides; |
| // this works because C++ supports covariant return types. |
| virtual Value* DeepCopy() const; |
| // Preferred version of DeepCopy. TODO(estade): remove the above. |
| std::unique_ptr<Value> CreateDeepCopy() const; |
| |
| // Compares if two Value objects have equal contents. |
| virtual bool Equals(const Value* other) const; |
| |
| // Compares if two Value objects have equal contents. Can handle NULLs. |
| // NULLs are considered equal but different from Value::CreateNullValue(). |
| static bool Equals(const Value* a, const Value* b); |
| |
| protected: |
| // These aren't safe for end-users, but they are useful for subclasses. |
| explicit Value(Type type); |
| Value(const Value& that); |
| Value& operator=(const Value& that); |
| |
| private: |
| Type type_; |
| }; |
| |
| // FundamentalValue represents the simple fundamental types of values. |
| class BASE_EXPORT FundamentalValue : public Value { |
| public: |
| explicit FundamentalValue(bool in_value); |
| explicit FundamentalValue(int in_value); |
| explicit FundamentalValue(double in_value); |
| ~FundamentalValue() override; |
| |
| // Overridden from Value: |
| bool GetAsBoolean(bool* out_value) const override; |
| bool GetAsInteger(int* out_value) const override; |
| // Values of both type TYPE_INTEGER and TYPE_DOUBLE can be obtained as |
| // doubles. |
| bool GetAsDouble(double* out_value) const override; |
| FundamentalValue* DeepCopy() const override; |
| bool Equals(const Value* other) const override; |
| |
| private: |
| union { |
| bool boolean_value_; |
| int integer_value_; |
| double double_value_; |
| }; |
| }; |
| |
| class BASE_EXPORT StringValue : public Value { |
| public: |
| // Initializes a StringValue with a UTF-8 narrow character string. |
| explicit StringValue(const std::string& in_value); |
| |
| ~StringValue() override; |
| |
| // Returns |value_| as a pointer or reference. |
| std::string* GetString(); |
| const std::string& GetString() const; |
| |
| // Overridden from Value: |
| bool GetAsString(std::string* out_value) const override; |
| bool GetAsString(const StringValue** out_value) const override; |
| StringValue* DeepCopy() const override; |
| bool Equals(const Value* other) const override; |
| |
| private: |
| std::string value_; |
| }; |
| |
| class BASE_EXPORT BinaryValue : public Value { |
| public: |
| // Creates a BinaryValue with a null buffer and size of 0. |
| BinaryValue(); |
| |
| // Creates a BinaryValue, taking ownership of the bytes pointed to by |
| // |buffer|. |
| BinaryValue(std::unique_ptr<char[]> buffer, size_t size); |
| |
| ~BinaryValue() override; |
| |
| // For situations where you want to keep ownership of your buffer, this |
| // factory method creates a new BinaryValue by copying the contents of the |
| // buffer that's passed in. |
| static std::unique_ptr<BinaryValue> CreateWithCopiedBuffer(const char* buffer, |
| size_t size); |
| |
| size_t GetSize() const { return size_; } |
| |
| // May return NULL. |
| char* GetBuffer() { return buffer_.get(); } |
| const char* GetBuffer() const { return buffer_.get(); } |
| |
| // Overridden from Value: |
| bool GetAsBinary(const BinaryValue** out_value) const override; |
| BinaryValue* DeepCopy() const override; |
| bool Equals(const Value* other) const override; |
| |
| private: |
| std::unique_ptr<char[]> buffer_; |
| size_t size_; |
| |
| DISALLOW_COPY_AND_ASSIGN(BinaryValue); |
| }; |
| |
| // DictionaryValue provides a key-value dictionary with (optional) "path" |
| // parsing for recursive access; see the comment at the top of the file. Keys |
| // are |std::string|s and should be UTF-8 encoded. |
| class BASE_EXPORT DictionaryValue : public Value { |
| public: |
| using Storage = std::map<std::string, std::unique_ptr<Value>>; |
| // Returns |value| if it is a dictionary, nullptr otherwise. |
| static std::unique_ptr<DictionaryValue> From(std::unique_ptr<Value> value); |
| |
| DictionaryValue(); |
| ~DictionaryValue() override; |
| |
| // Overridden from Value: |
| bool GetAsDictionary(DictionaryValue** out_value) override; |
| bool GetAsDictionary(const DictionaryValue** out_value) const override; |
| |
| // Returns true if the current dictionary has a value for the given key. |
| bool HasKey(const std::string& key) const; |
| |
| // Returns the number of Values in this dictionary. |
| size_t size() const { return dictionary_.size(); } |
| |
| // Returns whether the dictionary is empty. |
| bool empty() const { return dictionary_.empty(); } |
| |
| // Clears any current contents of this dictionary. |
| void Clear(); |
| |
| // Sets the Value associated with the given path starting from this object. |
| // A path has the form "<key>" or "<key>.<key>.[...]", where "." indexes |
| // into the next DictionaryValue down. Obviously, "." can't be used |
| // within a key, but there are no other restrictions on keys. |
| // If the key at any step of the way doesn't exist, or exists but isn't |
| // a DictionaryValue, a new DictionaryValue will be created and attached |
| // to the path in that location. |in_value| must be non-null. |
| void Set(const std::string& path, std::unique_ptr<Value> in_value); |
| // Deprecated version of the above. TODO(estade): remove. |
| void Set(const std::string& path, Value* in_value); |
| |
| // Convenience forms of Set(). These methods will replace any existing |
| // value at that path, even if it has a different type. |
| void SetBoolean(const std::string& path, bool in_value); |
| void SetInteger(const std::string& path, int in_value); |
| void SetDouble(const std::string& path, double in_value); |
| void SetString(const std::string& path, const std::string& in_value); |
| |
| // Like Set(), but without special treatment of '.'. This allows e.g. URLs to |
| // be used as paths. |
| void SetWithoutPathExpansion(const std::string& key, |
| std::unique_ptr<Value> in_value); |
| // Deprecated version of the above. TODO(estade): remove. |
| void SetWithoutPathExpansion(const std::string& key, Value* in_value); |
| |
| // Convenience forms of SetWithoutPathExpansion(). |
| void SetBooleanWithoutPathExpansion(const std::string& path, bool in_value); |
| void SetIntegerWithoutPathExpansion(const std::string& path, int in_value); |
| void SetDoubleWithoutPathExpansion(const std::string& path, double in_value); |
| void SetStringWithoutPathExpansion(const std::string& path, |
| const std::string& in_value); |
| |
| // Gets the Value associated with the given path starting from this object. |
| // A path has the form "<key>" or "<key>.<key>.[...]", where "." indexes |
| // into the next DictionaryValue down. If the path can be resolved |
| // successfully, the value for the last key in the path will be returned |
| // through the |out_value| parameter, and the function will return true. |
| // Otherwise, it will return false and |out_value| will be untouched. |
| // Note that the dictionary always owns the value that's returned. |
| // |out_value| is optional and will only be set if non-NULL. |
| bool Get(StringPiece path, const Value** out_value) const; |
| bool Get(StringPiece path, Value** out_value); |
| |
| // These are convenience forms of Get(). The value will be retrieved |
| // and the return value will be true if the path is valid and the value at |
| // the end of the path can be returned in the form specified. |
| // |out_value| is optional and will only be set if non-NULL. |
| bool GetBoolean(const std::string& path, bool* out_value) const; |
| bool GetInteger(const std::string& path, int* out_value) const; |
| // Values of both type TYPE_INTEGER and TYPE_DOUBLE can be obtained as |
| // doubles. |
| bool GetDouble(const std::string& path, double* out_value) const; |
| bool GetString(const std::string& path, std::string* out_value) const; |
| bool GetStringASCII(const std::string& path, std::string* out_value) const; |
| bool GetBinary(const std::string& path, const BinaryValue** out_value) const; |
| bool GetBinary(const std::string& path, BinaryValue** out_value); |
| bool GetDictionary(StringPiece path, |
| const DictionaryValue** out_value) const; |
| bool GetDictionary(StringPiece path, DictionaryValue** out_value); |
| bool GetList(const std::string& path, const ListValue** out_value) const; |
| bool GetList(const std::string& path, ListValue** out_value); |
| |
| // Like Get(), but without special treatment of '.'. This allows e.g. URLs to |
| // be used as paths. |
| bool GetWithoutPathExpansion(const std::string& key, |
| const Value** out_value) const; |
| bool GetWithoutPathExpansion(const std::string& key, Value** out_value); |
| bool GetBooleanWithoutPathExpansion(const std::string& key, |
| bool* out_value) const; |
| bool GetIntegerWithoutPathExpansion(const std::string& key, |
| int* out_value) const; |
| bool GetDoubleWithoutPathExpansion(const std::string& key, |
| double* out_value) const; |
| bool GetStringWithoutPathExpansion(const std::string& key, |
| std::string* out_value) const; |
| bool GetDictionaryWithoutPathExpansion( |
| const std::string& key, |
| const DictionaryValue** out_value) const; |
| bool GetDictionaryWithoutPathExpansion(const std::string& key, |
| DictionaryValue** out_value); |
| bool GetListWithoutPathExpansion(const std::string& key, |
| const ListValue** out_value) const; |
| bool GetListWithoutPathExpansion(const std::string& key, |
| ListValue** out_value); |
| |
| // Removes the Value with the specified path from this dictionary (or one |
| // of its child dictionaries, if the path is more than just a local key). |
| // If |out_value| is non-NULL, the removed Value will be passed out via |
| // |out_value|. If |out_value| is NULL, the removed value will be deleted. |
| // This method returns true if |path| is a valid path; otherwise it will |
| // return false and the DictionaryValue object will be unchanged. |
| virtual bool Remove(const std::string& path, |
| std::unique_ptr<Value>* out_value); |
| |
| // Like Remove(), but without special treatment of '.'. This allows e.g. URLs |
| // to be used as paths. |
| virtual bool RemoveWithoutPathExpansion(const std::string& key, |
| std::unique_ptr<Value>* out_value); |
| |
| // Removes a path, clearing out all dictionaries on |path| that remain empty |
| // after removing the value at |path|. |
| virtual bool RemovePath(const std::string& path, |
| std::unique_ptr<Value>* out_value); |
| |
| // Makes a copy of |this| but doesn't include empty dictionaries and lists in |
| // the copy. This never returns NULL, even if |this| itself is empty. |
| std::unique_ptr<DictionaryValue> DeepCopyWithoutEmptyChildren() const; |
| |
| // Merge |dictionary| into this dictionary. This is done recursively, i.e. any |
| // sub-dictionaries will be merged as well. In case of key collisions, the |
| // passed in dictionary takes precedence and data already present will be |
| // replaced. Values within |dictionary| are deep-copied, so |dictionary| may |
| // be freed any time after this call. |
| void MergeDictionary(const DictionaryValue* dictionary); |
| |
| // Swaps contents with the |other| dictionary. |
| virtual void Swap(DictionaryValue* other); |
| |
| // This class provides an iterator over both keys and values in the |
| // dictionary. It can't be used to modify the dictionary. |
| class BASE_EXPORT Iterator { |
| public: |
| explicit Iterator(const DictionaryValue& target); |
| Iterator(const Iterator& other); |
| ~Iterator(); |
| |
| bool IsAtEnd() const { return it_ == target_.dictionary_.end(); } |
| void Advance() { ++it_; } |
| |
| const std::string& key() const { return it_->first; } |
| const Value& value() const { return *it_->second; } |
| |
| private: |
| const DictionaryValue& target_; |
| Storage::const_iterator it_; |
| }; |
| |
| // Overridden from Value: |
| DictionaryValue* DeepCopy() const override; |
| // Preferred version of DeepCopy. TODO(estade): remove the above. |
| std::unique_ptr<DictionaryValue> CreateDeepCopy() const; |
| bool Equals(const Value* other) const override; |
| |
| private: |
| Storage dictionary_; |
| |
| DISALLOW_COPY_AND_ASSIGN(DictionaryValue); |
| }; |
| |
| // This type of Value represents a list of other Value values. |
| class BASE_EXPORT ListValue : public Value { |
| public: |
| using Storage = std::vector<std::unique_ptr<Value>>; |
| using const_iterator = Storage::const_iterator; |
| using iterator = Storage::iterator; |
| |
| // Returns |value| if it is a list, nullptr otherwise. |
| static std::unique_ptr<ListValue> From(std::unique_ptr<Value> value); |
| |
| ListValue(); |
| ~ListValue() override; |
| |
| // Clears the contents of this ListValue |
| void Clear(); |
| |
| // Returns the number of Values in this list. |
| size_t GetSize() const { return list_.size(); } |
| |
| // Returns whether the list is empty. |
| bool empty() const { return list_.empty(); } |
| |
| // Sets the list item at the given index to be the Value specified by |
| // the value given. If the index beyond the current end of the list, null |
| // Values will be used to pad out the list. |
| // Returns true if successful, or false if the index was negative or |
| // the value is a null pointer. |
| bool Set(size_t index, Value* in_value); |
| // Preferred version of the above. TODO(estade): remove the above. |
| bool Set(size_t index, std::unique_ptr<Value> in_value); |
| |
| // Gets the Value at the given index. Modifies |out_value| (and returns true) |
| // only if the index falls within the current list range. |
| // Note that the list always owns the Value passed out via |out_value|. |
| // |out_value| is optional and will only be set if non-NULL. |
| bool Get(size_t index, const Value** out_value) const; |
| bool Get(size_t index, Value** out_value); |
| |
| // Convenience forms of Get(). Modifies |out_value| (and returns true) |
| // only if the index is valid and the Value at that index can be returned |
| // in the specified form. |
| // |out_value| is optional and will only be set if non-NULL. |
| bool GetBoolean(size_t index, bool* out_value) const; |
| bool GetInteger(size_t index, int* out_value) const; |
| // Values of both type TYPE_INTEGER and TYPE_DOUBLE can be obtained as |
| // doubles. |
| bool GetDouble(size_t index, double* out_value) const; |
| bool GetString(size_t index, std::string* out_value) const; |
| bool GetBinary(size_t index, const BinaryValue** out_value) const; |
| bool GetBinary(size_t index, BinaryValue** out_value); |
| bool GetDictionary(size_t index, const DictionaryValue** out_value) const; |
| bool GetDictionary(size_t index, DictionaryValue** out_value); |
| bool GetList(size_t index, const ListValue** out_value) const; |
| bool GetList(size_t index, ListValue** out_value); |
| |
| // Removes the Value with the specified index from this list. |
| // If |out_value| is non-NULL, the removed Value AND ITS OWNERSHIP will be |
| // passed out via |out_value|. If |out_value| is NULL, the removed value will |
| // be deleted. This method returns true if |index| is valid; otherwise |
| // it will return false and the ListValue object will be unchanged. |
| virtual bool Remove(size_t index, std::unique_ptr<Value>* out_value); |
| |
| // Removes the first instance of |value| found in the list, if any, and |
| // deletes it. |index| is the location where |value| was found. Returns false |
| // if not found. |
| bool Remove(const Value& value, size_t* index); |
| |
| // Removes the element at |iter|. If |out_value| is NULL, the value will be |
| // deleted, otherwise ownership of the value is passed back to the caller. |
| // Returns an iterator pointing to the location of the element that |
| // followed the erased element. |
| iterator Erase(iterator iter, std::unique_ptr<Value>* out_value); |
| |
| // Appends a Value to the end of the list. |
| void Append(std::unique_ptr<Value> in_value); |
| // Deprecated version of the above. TODO(estade): remove. |
| void Append(Value* in_value); |
| |
| // Convenience forms of Append. |
| void AppendBoolean(bool in_value); |
| void AppendInteger(int in_value); |
| void AppendDouble(double in_value); |
| void AppendString(const std::string& in_value); |
| void AppendStrings(const std::vector<std::string>& in_values); |
| |
| // Appends a Value if it's not already present. Takes ownership of the |
| // |in_value|. Returns true if successful, or false if the value was already |
| // present. If the value was already present the |in_value| is deleted. |
| bool AppendIfNotPresent(Value* in_value); |
| |
| // Insert a Value at index. |
| // Returns true if successful, or false if the index was out of range. |
| bool Insert(size_t index, Value* in_value); |
| |
| // Searches for the first instance of |value| in the list using the Equals |
| // method of the Value type. |
| // Returns a const_iterator to the found item or to end() if none exists. |
| const_iterator Find(const Value& value) const; |
| |
| // Swaps contents with the |other| list. |
| virtual void Swap(ListValue* other); |
| |
| // Iteration. |
| iterator begin() { return list_.begin(); } |
| iterator end() { return list_.end(); } |
| |
| const_iterator begin() const { return list_.begin(); } |
| const_iterator end() const { return list_.end(); } |
| |
| // Overridden from Value: |
| bool GetAsList(ListValue** out_value) override; |
| bool GetAsList(const ListValue** out_value) const override; |
| ListValue* DeepCopy() const override; |
| bool Equals(const Value* other) const override; |
| |
| // Preferred version of DeepCopy. TODO(estade): remove DeepCopy. |
| std::unique_ptr<ListValue> CreateDeepCopy() const; |
| |
| private: |
| Storage list_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ListValue); |
| }; |
| |
| // Stream operator so Values can be used in assertion statements. In order that |
| // gtest uses this operator to print readable output on test failures, we must |
| // override each specific type. Otherwise, the default template implementation |
| // is preferred over an upcast. |
| BASE_EXPORT std::ostream& operator<<(std::ostream& out, const Value& value); |
| |
| BASE_EXPORT inline std::ostream& operator<<(std::ostream& out, |
| const FundamentalValue& value) { |
| return out << static_cast<const Value&>(value); |
| } |
| |
| BASE_EXPORT inline std::ostream& operator<<(std::ostream& out, |
| const StringValue& value) { |
| return out << static_cast<const Value&>(value); |
| } |
| |
| BASE_EXPORT inline std::ostream& operator<<(std::ostream& out, |
| const DictionaryValue& value) { |
| return out << static_cast<const Value&>(value); |
| } |
| |
| BASE_EXPORT inline std::ostream& operator<<(std::ostream& out, |
| const ListValue& value) { |
| return out << static_cast<const Value&>(value); |
| } |
| |
| } // namespace base |
| |
| #endif // BASE_VALUES_H_ |