Inline FundamentalValue into base::Value

base/values.h

 // 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.
@@ skipping 43 matching lines @@
     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.
   };
 
+  Value();  // A null value.
+
   virtual ~Value();
 
   static std::unique_ptr<Value> CreateNullValue();
 
   // Returns the name for a given |type|.
   static const char* GetTypeName(Type type);
 
   // 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_; }
+  Type GetType() const { return type_; }  // DEPRECATED, use type().
+  Type type() const { return type_; }
 
   // Returns true if the current object represents a given type.
   bool IsType(Type type) const { return type == type_; }
+  bool is_bool() const { return type() == TYPE_BOOLEAN; }
+  bool is_int() const { return type() == TYPE_INTEGER; }
+  bool is_double() const { return type() == TYPE_DOUBLE; }
+  bool is_string() const { return type() == TYPE_STRING; }
+  bool is_blob() const { return type() == TYPE_BINARY; }
+  bool is_dict() const { return type() == TYPE_DICTIONARY; }
+  bool is_list() const { return type() == TYPE_LIST; }
+
+  // These will all fatally assert if the type doesn't match.
+  bool GetBool() const;
+  int GetInt() const;
+  double GetDouble() const;  // Implicitly converts from int if necessary.
 
   // 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;
@@ skipping 22 matching lines @@
   // 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);
 
+  // TODO(brettw) move to public when FundamentalValue is gone.
+  Value(bool in_bool);
+  Value(int in_int);
+  Value(double in_double);
+
  private:
   Type type_;
+
+  union {
+    bool bool_value_;
+    int int_value_;
+    double double_value_;
+  };
 };
 
 // FundamentalValue represents the simple fundamental types of values.
+// TODO(brettw) remove when callers are updated to use raw Value.
 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 {

[vabr (Chromium), 2016/12/07 14:31:11]

As a result of moving this union up to base::Value, the generated
copy-constructor for FundamentalValue breaks.

Before:
FundamentalValue(const FundamentalValue&) was composed of the part generated by
the compiler to copy the union and from the user-defined base::Value
copy-constructor, which copies the type enum.

After:
While the FV constructor is still generated, it is trivial for the
non-base::Value part (there are no added members). The base::Value
copy-constructor continues to only copy the type. Hence, the values are
discarded.

-    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(StringPiece in_value);
 
   // Initializes a StringValue with a string16.
   explicit StringValue(const string16& in_value);
 
@@ skipping 399 matching lines @@
 }
 
 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_