Clarify Value::Get*()'s interface to reflect the current implementation.

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 115 matching lines @@
 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;
+  // Values of both type TYPE_INTEGER and TYPE_DOUBLE can be obtained as
+  // doubles.
   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_;
   };
@@ skipping 114 matching lines @@
   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.
+  // |out_value| is optional and will only be set if non-NULL.
   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.
+  // |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 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;
@@ skipping 105 matching lines @@
   // 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|.
+  // |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 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);
 
@@ skipping 102 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_