Use std::nullptr_t in dynamic

[folly.git] / folly / dynamic.h

diff --git a/folly/dynamic.h b/folly/dynamic.h
index 2dc49434cbf32c386e7bf734533efacf3e7ec1b4..a62805090dd9058938830571b6112c77bf273624 100644 (file)
--- a/folly/dynamic.h
+++ b/folly/dynamic.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,16 +45,6 @@
  * Also see folly/json.h for the serialization and deserialization
  * functions for JSON.
  *
- * Note: dynamic is not DefaultConstructible.  Rationale:
- *
- *   - The intuitive thing to initialize a defaulted dynamic to would
- *     be nullptr.
- *
- *   - However, the expression dynamic d = {} is required to call the
- *     default constructor by the standard, which is confusing
- *     behavior for dynamic unless the default constructor creates an
- *     empty array.
- *
  * Additional documentation is in folly/docs/Dynamic.md.
  *
  * @author Jordan DeLong <delong.j@fb.com>
@@ -95,6 +85,7 @@ struct dynamic : private boost::operators<dynamic> {
     OBJECT,
     STRING,
   };
+  template<class T, class Enable = void> struct NumericTypeHelper;
 
   /*
    * We support direct iteration of arrays, and indirect iteration of objects.
@@ -108,12 +99,17 @@ struct dynamic : private boost::operators<dynamic> {
 private:
   typedef std::vector<dynamic> Array;
 public:
+  typedef Array::iterator iterator;
   typedef Array::const_iterator const_iterator;
   typedef dynamic value_type;
+
   struct const_key_iterator;
   struct const_value_iterator;
   struct const_item_iterator;
 
+  struct value_iterator;
+  struct item_iterator;
+
   /*
    * Creation routines for making dynamic objects and arrays.  Objects
    * are maps from key to value (so named due to json-related origins
@@ -143,18 +139,20 @@ public:
   static dynamic array(Args&& ...args);
 
   static ObjectMaker object();
-  static ObjectMaker object(dynamic&&, dynamic&&);
-  static ObjectMaker object(dynamic const&, dynamic&&);
-  static ObjectMaker object(dynamic&&, dynamic const&);
-  static ObjectMaker object(dynamic const&, dynamic const&);
+  static ObjectMaker object(dynamic, dynamic);
+
+  /**
+   * Default constructor, initializes with nullptr.
+   */
+  dynamic();
 
   /*
    * String compatibility constructors.
    */
+  /* implicit */ dynamic(std::nullptr_t);
   /* implicit */ dynamic(StringPiece val);
   /* implicit */ dynamic(char const* val);
-  /* implicit */ dynamic(std::string const& val);
-  /* implicit */ dynamic(std::string&& val);
+  /* implicit */ dynamic(std::string val);
 
   /*
    * This is part of the plumbing for array() and object(), above.
@@ -166,15 +164,18 @@ public:
   /* implicit */ dynamic(ObjectMaker&&);
 
   /*
-   * Conversion constructors from most of the other types.
+   * Constructors for integral and float types.
+   * Other types are SFINAEd out with NumericTypeHelper.
    */
-  template<class T> /* implicit */ dynamic(T t);
+  template<class T, class NumericType = typename NumericTypeHelper<T>::type>
+  /* implicit */ dynamic(T t);
 
   /*
    * Create a dynamic that is an array of the values from the supplied
    * iterator range.
    */
-  template<class Iterator> dynamic(Iterator first, Iterator last);
+  template<class Iterator>
+  explicit dynamic(Iterator first, Iterator last);
 
   dynamic(dynamic const&);
   dynamic(dynamic&&) noexcept;
@@ -324,6 +325,8 @@ public:
    */
   const_iterator begin()  const;
   const_iterator end()    const;
+  iterator begin();
+  iterator end();
 
 private:
   /*
@@ -339,6 +342,8 @@ public:
   IterableProxy<const_key_iterator> keys() const;
   IterableProxy<const_value_iterator> values() const;
   IterableProxy<const_item_iterator> items() const;
+  IterableProxy<value_iterator> values();
+  IterableProxy<item_iterator> items();
 
   /*
    * AssociativeContainer-style find interface for objects.  Throws if
@@ -348,6 +353,7 @@ public:
    * const_item_iterator pointing to the item.
    */
   const_item_iterator find(dynamic const&) const;
+  item_iterator find(dynamic const&);
 
   /*
    * If this is an object, returns whether it contains a field with
@@ -479,19 +485,17 @@ public:
    * removed, or end() if there are none.  (The iteration order does
    * not change.)
    */
-  const_iterator erase(const_iterator it);
-  const_iterator erase(const_iterator first, const_iterator last);
+  iterator erase(const_iterator it);
+  iterator erase(const_iterator first, const_iterator last);
 
   const_key_iterator erase(const_key_iterator it);
   const_key_iterator erase(const_key_iterator first, const_key_iterator last);
 
-  const_value_iterator erase(const_value_iterator it);
-  const_value_iterator erase(const_value_iterator first,
-                             const_value_iterator last);
+  value_iterator erase(const_value_iterator it);
+  value_iterator erase(const_value_iterator first, const_value_iterator last);
 
-  const_item_iterator erase(const_item_iterator it);
-  const_item_iterator erase(const_item_iterator first,
-                            const_item_iterator last);
+  item_iterator erase(const_item_iterator it);
+  item_iterator erase(const_item_iterator first, const_item_iterator last);
   /*
    * Append elements to an array.  If this is not an array, throws
    * TypeError.
@@ -548,9 +552,7 @@ private:
     explicit Data() : nul(nullptr) {}
     ~Data() {}
 
-    // XXX: gcc does an ICE if we use std::nullptr_t instead of void*
-    // here.  See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50361
-    void* nul;
+    std::nullptr_t nul;
     Array array;
     bool boolean;
     double doubl;