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+// Copyright (c) 2011 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 setting and other persistable data. It includes the ability to
+// specify (recursive) lists and dictionaries, so it's fairly expressive.
+// However, the API is optimized for the common case, namely storing a
+// hierarchical tree of simple values. Given a DictionaryValue root, you can
+// easily do things like:
+//
+// root->SetString("global.pages.homepage", "http://goateleporter.com");
+// std::string homepage = "http://google.com"; // default/fallback value
+// root->GetString("global.pages.homepage", &homepage);
+//
+// where "global" and "pages" are also DictionaryValues, and "homepage" is a
+// string setting. If some elements of the path didn't exist yet, the
+// SetString() method would create the missing elements and attach them to root
+// before attaching the homepage value.
+
+#ifndef BASE_VALUES_H_
+#define BASE_VALUES_H_
+#pragma once
+
+#include <iterator>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/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 BinaryValue;
+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.
+class BASE_EXPORT Value {
+ public:
+ enum Type {
+ TYPE_NULL = 0,
+ TYPE_BOOLEAN,
+ TYPE_INTEGER,
+ TYPE_DOUBLE,
+ TYPE_STRING,
+ TYPE_BINARY,
+ TYPE_DICTIONARY,
+ TYPE_LIST
+ };
+
+ virtual ~Value();
+
+ // Convenience methods for creating Value objects for various
+ // kinds of values without thinking about which class implements them.
+ // These can always be expected to return a valid Value*.
+ static Value* CreateNullValue();
+ 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 settings.
+ // If the current setting 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;
+
+ // 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:
+ // This isn't safe for end-users (they should use the Create*Value()
+ // static methods above), but it's useful for subclasses.
+ explicit Value(Type type);
+
+ private:
+ Value();
+
+ Type type_;
+
+ DISALLOW_COPY_AND_ASSIGN(Value);
+};
+
+// 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_;
+ };
+
+ DISALLOW_COPY_AND_ASSIGN(FundamentalValue);
+};
+
+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_;
+
+ DISALLOW_COPY_AND_ASSIGN(StringValue);
+};
+
+class BASE_EXPORT BinaryValue: public Value {
+ public:
+ virtual ~BinaryValue();
+
+ // Creates a Value to represent a binary buffer. The new object takes
+ // ownership of the pointer passed in, if successful.
+ // Returns NULL if buffer is NULL.
+ static BinaryValue* Create(char* buffer, size_t size);
+
+ // 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.
+ // Returns NULL if buffer is NULL.
+ static BinaryValue* CreateWithCopiedBuffer(const char* buffer, size_t size);
+
+ size_t GetSize() const { return size_; }
+ char* GetBuffer() { return buffer_; }
+ const char* GetBuffer() const { return buffer_; }
+
+ // Overridden from Value:
+ virtual BinaryValue* DeepCopy() const OVERRIDE;
+ virtual bool Equals(const Value* other) const OVERRIDE;
+
+ private:
+ // Constructor is private so that only objects with valid buffer pointers
+ // and size values can be created.
+ BinaryValue(char* buffer, size_t size);
+
+ 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();
+
+ // 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);
+
+ // 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, Value** out_value) const;
+
+ // 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, BinaryValue** out_value) const;
+ bool GetDictionary(const std::string& path,
+ DictionaryValue** out_value) const;
+ bool GetList(const std::string& path, ListValue** out_value) const;
+
+ // Like Get(), but without special treatment of '.'. This allows e.g. URLs to
+ // be used as paths.
+ bool GetWithoutPathExpansion(const std::string& key,
+ Value** 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,
+ DictionaryValue** out_value) const;
+ bool GetListWithoutPathExpansion(const std::string& key,
+ ListValue** out_value) const;
+
+ // 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 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 |path| is a valid path; otherwise
+ // it will return false and the DictionaryValue object will be unchanged.
+ bool Remove(const std::string& path, Value** out_value);
+
+ // Like Remove(), but without special treatment of '.'. This allows e.g. URLs
+ // to be used as paths.
+ bool RemoveWithoutPathExpansion(const std::string& key, 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();
+
+ // Merge a given dictionary into this dictionary. This is done recursively,
+ // i.e. any subdictionaries will be merged as well. In case of key collisions,
+ // the passed in dictionary takes precedence and data already present will be
+ // replaced.
+ void MergeDictionary(const DictionaryValue* dictionary);
+
+ // Swaps contents with the |other| dictionary.
+ void Swap(DictionaryValue* other) {
+ dictionary_.swap(other->dictionary_);
+ }
+
+ // This class provides an iterator for the keys in the dictionary.
+ // It can't be used to modify the dictionary.
+ //
+ // YOU SHOULD ALWAYS USE THE XXXWithoutPathExpansion() APIs WITH THESE, NOT
+ // THE NORMAL XXX() APIs. This makes sure things will work correctly if any
+ // keys have '.'s in them.
+ class key_iterator
+ : private std::iterator<std::input_iterator_tag, const std::string> {
+ public:
+ explicit key_iterator(ValueMap::const_iterator itr) { itr_ = itr; }
+ key_iterator operator++() {
+ ++itr_;
+ return *this;
+ }
+ const std::string& operator*() { return itr_->first; }
+ bool operator!=(const key_iterator& other) { return itr_ != other.itr_; }
+ bool operator==(const key_iterator& other) { return itr_ == other.itr_; }
+
+ private:
+ ValueMap::const_iterator itr_;
+ };
+
+ key_iterator begin_keys() const { return key_iterator(dictionary_.begin()); }
+ key_iterator end_keys() const { return key_iterator(dictionary_.end()); }
+
+ // 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, Value** out_value) const;
+
+ // 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, BinaryValue** out_value) const;
+ bool GetDictionary(size_t index, DictionaryValue** out_value) const;
+ bool GetList(size_t index, ListValue** out_value) const;
+
+ // 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.
+ bool Remove(size_t index, 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);
+
+ // Appends a Value to the end of the list.
+ void Append(Value* in_value);
+
+ // 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);
+
+ // Swaps contents with the |other| list.
+ void Swap(ListValue* other) {
+ list_.swap(other->list_);
+ }
+
+ // 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;
+};
+
+} // namespace base
+
+// http://crbug.com/88666
+using base::DictionaryValue;
+using base::ListValue;
+using base::StringValue;
+using base::Value;
+
+#endif // BASE_VALUES_H_