Index: base/memory/ptr_util.h |
diff --git a/base/memory/ptr_util.h b/base/memory/ptr_util.h |
index 04f2c0258929e74c0bcca89d4433fa6f647a0d28..8747ac9463323865a28eb7d0baf9a6367ab7b5df 100644 |
--- a/base/memory/ptr_util.h |
+++ b/base/memory/ptr_util.h |
@@ -6,6 +6,7 @@ |
#define BASE_MEMORY_PTR_UTIL_H_ |
#include <memory> |
+#include <utility> |
namespace base { |
@@ -17,6 +18,57 @@ std::unique_ptr<T> WrapUnique(T* ptr) { |
return std::unique_ptr<T>(ptr); |
} |
+namespace internal { |
+ |
+template <typename T> |
+struct MakeUniqueResult { |
+ using Scalar = std::unique_ptr<T>; |
+}; |
+ |
+template <typename T> |
+struct MakeUniqueResult<T[]> { |
+ using Array = std::unique_ptr<T[]>; |
+}; |
+ |
+template <typename T, size_t N> |
+struct MakeUniqueResult<T[N]> { |
+ using Invalid = void; |
+}; |
+ |
+} // namespace internal |
+ |
+// Helper to construct an object wrapped in a std::unique_ptr. This is an |
+// implementation of C++14's std::make_unique that can be used in Chrome. |
+// |
+// MakeUnique<T>(args) should be preferred over WrapUnique(new T(args)): bare |
+// calls to `new` should be treated with scrutiny. |
Ryan Sleevi
2015/12/15 23:53:40
Is this level of warning needed?
That is, it seem
dcheng
2015/12/15 23:59:50
It seems like you could still get the former patte
|
+// |
+// Usage: |
+// // ptr is a std::unique_ptr<std::string> |
+// auto ptr = MakeUnique<std::string>("hello world!"); |
+// |
+// // arr is a std::unique_ptr<int[]> |
+// auto arr = MakeUnique<int[]>(5); |
+ |
+// Overload for non-array types. Arguments are forwarded to T's constructor. |
+template <typename T, typename... Args> |
+typename internal::MakeUniqueResult<T>::Scalar MakeUnique(Args&&... args) { |
+ return std::unique_ptr<T>(new T(std::forward<Args>(args)...)); |
+} |
+ |
+// Overload for array types of unknown bound, e.g. T[]. The array is allocated |
+// with `new T[n]()` and value-initialized: note that this is distinct from |
+// `new T[n]`, which default-initializes. |
+template <typename T> |
+typename internal::MakeUniqueResult<T>::Array MakeUnique(size_t size) { |
+ return std::unique_ptr<T>(new typename std::remove_extent<T>::type[size]()); |
+} |
+ |
+// Overload to reject array types of known bound, e.g. T[n]. |
+template <typename T, typename... Args> |
+typename internal::MakeUniqueResult<T>::Invalid MakeUnique(Args&&... args) = |
+ delete; |
+ |
} // namespace base |
#endif // BASE_MEMORY_PTR_UTIL_H_ |