summaryrefslogtreecommitdiff
path: root/absl/memory/memory.h
diff options
context:
space:
mode:
Diffstat (limited to 'absl/memory/memory.h')
-rw-r--r--absl/memory/memory.h102
1 files changed, 6 insertions, 96 deletions
diff --git a/absl/memory/memory.h b/absl/memory/memory.h
index d6332606..e5ff0e65 100644
--- a/absl/memory/memory.h
+++ b/absl/memory/memory.h
@@ -75,32 +75,6 @@ std::unique_ptr<T> WrapUnique(T* ptr) {
return std::unique_ptr<T>(ptr);
}
-namespace memory_internal {
-
-// Traits to select proper overload and return type for `absl::make_unique<>`.
-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 memory_internal
-
-// gcc 4.8 has __cplusplus at 201301 but the libstdc++ shipped with it doesn't
-// define make_unique. Other supported compilers either just define __cplusplus
-// as 201103 but have make_unique (msvc), or have make_unique whenever
-// __cplusplus > 201103 (clang).
-#if (__cplusplus > 201103L || defined(_MSC_VER)) && \
- !(defined(__GLIBCXX__) && !defined(__cpp_lib_make_unique))
-using std::make_unique;
-#else
// -----------------------------------------------------------------------------
// Function Template: make_unique<T>()
// -----------------------------------------------------------------------------
@@ -109,82 +83,18 @@ using std::make_unique;
// during the construction process. `absl::make_unique<>` also avoids redundant
// type declarations, by avoiding the need to explicitly use the `new` operator.
//
-// This implementation of `absl::make_unique<>` is designed for C++11 code and
-// will be replaced in C++14 by the equivalent `std::make_unique<>` abstraction.
-// `absl::make_unique<>` is designed to be 100% compatible with
-// `std::make_unique<>` so that the eventual migration will involve a simple
-// rename operation.
+// https://en.cppreference.com/w/cpp/memory/unique_ptr/make_unique
//
// For more background on why `std::unique_ptr<T>(new T(a,b))` is problematic,
// see Herb Sutter's explanation on
// (Exception-Safe Function Calls)[https://herbsutter.com/gotw/_102/].
// (In general, reviewers should treat `new T(a,b)` with scrutiny.)
//
-// Example usage:
-//
-// auto p = make_unique<X>(args...); // 'p' is a std::unique_ptr<X>
-// auto pa = make_unique<X[]>(5); // 'pa' is a std::unique_ptr<X[]>
-//
-// Three overloads of `absl::make_unique` are required:
-//
-// - For non-array T:
-//
-// Allocates a T with `new T(std::forward<Args> args...)`,
-// forwarding all `args` to T's constructor.
-// Returns a `std::unique_ptr<T>` owning that object.
-//
-// - For an array of unknown bounds T[]:
-//
-// `absl::make_unique<>` will allocate an array T of type U[] with
-// `new U[n]()` and return a `std::unique_ptr<U[]>` owning that array.
-//
-// Note that 'U[n]()' is different from 'U[n]', and elements will be
-// value-initialized. Note as well that `std::unique_ptr` will perform its
-// own destruction of the array elements upon leaving scope, even though
-// the array [] does not have a default destructor.
-//
-// NOTE: an array of unknown bounds T[] may still be (and often will be)
-// initialized to have a size, and will still use this overload. E.g:
-//
-// auto my_array = absl::make_unique<int[]>(10);
-//
-// - For an array of known bounds T[N]:
-//
-// `absl::make_unique<>` is deleted (like with `std::make_unique<>`) as
-// this overload is not useful.
-//
-// NOTE: an array of known bounds T[N] is not considered a useful
-// construction, and may cause undefined behavior in templates. E.g:
-//
-// auto my_array = absl::make_unique<int[10]>();
-//
-// In those cases, of course, you can still use the overload above and
-// simply initialize it to its desired size:
-//
-// auto my_array = absl::make_unique<int[]>(10);
-
-// `absl::make_unique` overload for non-array types.
-template <typename T, typename... Args>
-typename memory_internal::MakeUniqueResult<T>::scalar make_unique(
- Args&&... args) {
- return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
-}
-
-// `absl::make_unique` overload for an array T[] of unknown bounds.
-// The array allocation needs to use the `new T[size]` form and cannot take
-// element constructor arguments. The `std::unique_ptr` will manage destructing
-// these array elements.
-template <typename T>
-typename memory_internal::MakeUniqueResult<T>::array make_unique(size_t n) {
- return std::unique_ptr<T>(new typename absl::remove_extent_t<T>[n]());
-}
-
-// `absl::make_unique` overload for an array T[N] of known bounds.
-// This construction will be rejected.
-template <typename T, typename... Args>
-typename memory_internal::MakeUniqueResult<T>::invalid make_unique(
- Args&&... /* args */) = delete;
-#endif
+// Historical note: Abseil once provided a C++11 compatible implementation of
+// the C++14's `std::make_unique`. Now that C++11 support has been sunsetted,
+// `absl::make_unique` simply uses the STL-provided implementation. New code
+// should use `std::make_unique`.
+using std::make_unique;
// -----------------------------------------------------------------------------
// Function Template: RawPtr()