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 // 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 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 <iosfwd>

 #include <map>

 #include <string>

 #include <utility>

 #include <vector>

 #include "base/base_export.h"

 #include "base/basictypes.h"

 #include "base/compiler_specific.h"

 #include "base/memory/scoped_ptr.h"

 #include "base/strings/string16.h"

 // This file declares "using base::Value", etc. at the bottom, so that

 // current code can use these classes without the base namespace. In

 // new code, please always use base::Value, etc. or add your own

 // "using" declaration.

 // http://crbug.com/88666

 namespace base {

 class DictionaryValue;

 class FundamentalValue;

 class ListValue;

 class StringValue;

 class Value;

 typedef std::vector<Value*> ValueVector;

 typedef std::map<std::string, Value*> ValueMap;

 // 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 Value* CreateNullValue();

   // DEPRECATED: Do not use the following 5 functions. Instead, use

   // new FundamentalValue or new StringValue.

   static FundamentalValue* CreateBooleanValue(bool in_value);

   static FundamentalValue* CreateIntegerValue(int in_value);

   static FundamentalValue* CreateDoubleValue(double in_value);

   static StringValue* CreateStringValue(const std::string& in_value);

   static StringValue* CreateStringValue(const string16& in_value);

   // 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(string16* 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;

   // 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);

   virtual ~FundamentalValue();

   // Overridden from Value:

   virtual bool GetAsBoolean(bool* out_value) const OVERRIDE;

   virtual bool GetAsInteger(int* out_value) const OVERRIDE;

   virtual bool GetAsDouble(double* out_value) const OVERRIDE;

   virtual FundamentalValue* DeepCopy() const OVERRIDE;

   virtual 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);

   // Initializes a StringValue with a string16.

   explicit StringValue(const string16& in_value);

   virtual ~StringValue();

   // Overridden from Value:

   virtual bool GetAsString(std::string* out_value) const OVERRIDE;

   virtual bool GetAsString(string16* out_value) const OVERRIDE;

   virtual StringValue* DeepCopy() const OVERRIDE;

   virtual 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(scoped_ptr<char[]> buffer, size_t size);

   virtual ~BinaryValue();

   // 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 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:

   virtual BinaryValue* DeepCopy() const OVERRIDE;

   virtual bool Equals(const Value* other) const OVERRIDE;

  private:

   scoped_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:

   DictionaryValue();

   virtual ~DictionaryValue();

   // Overridden from Value:

   virtual bool GetAsDictionary(DictionaryValue** out_value) OVERRIDE;

   virtual 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.

   // Note that the dictionary takes ownership of the value referenced by

   // |in_value|, and therefore |in_value| must be non-NULL.

   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);

   void SetString(const std::string& path, const string16& 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, 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);

   void SetStringWithoutPathExpansion(const std::string& path,

                                      const string16& 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.

   bool Get(const std::string& path, const Value** out_value) const;

   bool Get(const std::string& 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.

   bool GetBoolean(const std::string& path, bool* out_value) const;

   bool GetInteger(const std::string& path, int* out_value) const;

   bool GetDouble(const std::string& path, double* out_value) const;

   bool GetString(const std::string& path, std::string* out_value) const;

   bool GetString(const std::string& path, string16* 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(const std::string& path,

                      const DictionaryValue** out_value) const;

   bool GetDictionary(const std::string& 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 GetStringWithoutPathExpansion(const std::string& key,

                                      string16* 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, scoped_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,

                                           scoped_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.

   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);

     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_;

     ValueMap::const_iterator it_;

   };

   // Overridden from Value:

   virtual DictionaryValue* DeepCopy() const OVERRIDE;

   virtual bool Equals(const Value* other) const OVERRIDE;

  private:

   ValueMap dictionary_;

   DISALLOW_COPY_AND_ASSIGN(DictionaryValue);

 };

 // This type of Value represents a list of other Value values.

 class BASE_EXPORT ListValue : public Value {

  public:

   typedef ValueVector::iterator iterator;

   typedef ValueVector::const_iterator const_iterator;

   ListValue();

   virtual ~ListValue();

   // 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);

   // 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|.

   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.

   bool GetBoolean(size_t index, bool* out_value) const;

   bool GetInteger(size_t index, int* out_value) const;

   bool GetDouble(size_t index, double* out_value) const;

   bool GetString(size_t index, std::string* out_value) const;

   bool GetString(size_t index, string16* 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, scoped_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, scoped_ptr<Value>* out_value);

   // Appends a Value to the end of the list.

   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 AppendString(const string16& in_value);

   void AppendStrings(const std::vector<std::string>& in_values);

   void AppendStrings(const std::vector<string16>& 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:

   virtual bool GetAsList(ListValue** out_value) OVERRIDE;

   virtual bool GetAsList(const ListValue** out_value) const OVERRIDE;

   virtual ListValue* DeepCopy() const OVERRIDE;

   virtual bool Equals(const Value* other) const OVERRIDE;

  private:

   ValueVector list_;

   DISALLOW_COPY_AND_ASSIGN(ListValue);

 };

 // This interface is implemented by classes that know how to serialize and

 // deserialize Value objects.

 class BASE_EXPORT ValueSerializer {

  public:

   virtual ~ValueSerializer();

   virtual bool Serialize(const Value& root) = 0;

   // This method deserializes the subclass-specific format into a Value object.

   // If the return value is non-NULL, the caller takes ownership of returned

   // Value. If the return value is NULL, and if error_code is non-NULL,

   // error_code will be set with the underlying error.

   // If |error_message| is non-null, it will be filled in with a formatted

   // error message including the location of the error if appropriate.

   virtual Value* Deserialize(int* error_code, std::string* error_str) = 0;

 };

 // 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

 // http://crbug.com/88666

 using base::DictionaryValue;

 using base::ListValue;

 using base::StringValue;

 using base::Value;

 #endif  // BASE_VALUES_H_