Add make_indirect and make_polymorphic extensions

BUILD.bazel

@@ -13,6 +13,7 @@ cc_library(
     srcs = ["indirect.cc"],
     hdrs = ["indirect.h"],
     copts = ["-Iexternal/value_types/"],
+    defines = ["XYZ_HAS_EXTENSION_MAKE_INDIRECT"],
     visibility = ["//visibility:public"],
     deps = ["feature_check"],
 )
@@ -91,6 +92,7 @@ cc_library(
     srcs = ["polymorphic.cc"],
     hdrs = ["polymorphic.h"],
     copts = ["-Iexternal/value_types/"],
+    defines = ["XYZ_HAS_EXTENSION_MAKE_POLYMORPHIC"],
     visibility = ["//visibility:public"],
 )
 

CMakeLists.txt

@@ -39,6 +39,7 @@ target_sources(xyz_value_types
 xyz_add_library(
     NAME indirect
     ALIAS xyz_value_types::indirect
+    DEFINITIONS XYZ_HAS_EXTENSION_MAKE_INDIRECT
 )
 target_sources(indirect
     INTERFACE
@@ -75,6 +76,7 @@ target_sources(indirect_cxx17
 xyz_add_library(
     NAME polymorphic
     ALIAS xyz_value_types::polymorphic
+    DEFINITIONS XYZ_HAS_EXTENSION_MAKE_POLYMORPHIC
 )
 target_sources(polymorphic
     INTERFACE

indirect.h

@@ -463,6 +463,18 @@ template <typename Alloc, typename Value>
 indirect(std::allocator_arg_t, Alloc, Value) -> indirect<
     Value, typename std::allocator_traits<Alloc>::template rebind_alloc<Value>>;
 
+#ifdef XYZ_HAS_EXTENSION_MAKE_INDIRECT
+template <typename T, typename... Us>
+auto make_indirect(Us&&... us) -> indirect<T> {
+  return indirect<T>(std::in_place, std::forward<Us>(us)...);
+}
+
+template <typename T, typename A, typename... Us>
+auto allocate_indirect(A a, Us&&... us) -> indirect<T, A> {
+  return indirect<T, A>(std::allocator_arg, a, std::in_place,
+                        std::forward<Us>(us)...);
+}
+#endif  // XYZ_HAS_EXTENSION_MAKE_INDIRECT
 }  // namespace xyz
 
 template <class T, class Alloc>

indirect_test.cc

@@ -1015,8 +1015,6 @@ TEST(IndirectTest, SupportNonCopyableType) {
   EXPECT_TRUE(a.valueless_after_move());
 }
 
-}  // namespace
-
 struct NonThreeWayComparable {
   int x_;
 
@@ -1052,3 +1050,30 @@ TEST(IndirectTest, NonThreeWayComparable) {
   EXPECT_TRUE(i != ii);
 }
 #endif  // XYZ_HAS_STD_THREE_WAY_COMPARISON
+
+#ifdef XYZ_HAS_EXTENSION_MAKE_INDIRECT
+TEST(IndirectTest, MakeIndirectNoArgs) {
+  auto i = xyz::make_indirect<int>();
+  EXPECT_EQ(*i, 0);
+}
+
+TEST(IndirectTest, MakeIndirect) {
+  auto i = xyz::make_indirect<int>(42);
+  EXPECT_EQ(*i, 42);
+}
+
+TEST(IndirectTest, AllocateIndirectNoArgs) {
+  auto a = xyz::TaggedAllocator<int>(1);
+  auto i = xyz::allocate_indirect<int>(a);
+  EXPECT_EQ(*i, 0);
+  EXPECT_EQ(i.get_allocator().tag, 1);
+}
+
+TEST(IndirectTest, AllocateIndirect) {
+  auto a = xyz::TaggedAllocator<int>(1);
+  auto i = xyz::allocate_indirect<int>(a, 42);
+  EXPECT_EQ(*i, 42);
+  EXPECT_EQ(i.get_allocator().tag, 1);
+}
+#endif  // XYZ_HAS_EXTENSION_MAKE_INDIRECT
+}  // namespace

polymorphic.h

@@ -403,8 +403,20 @@ class polymorphic {
       cb_ = nullptr;
     }
   }
-};  // namespace xyz
+};
+
+#ifdef XYZ_HAS_EXTENSION_MAKE_POLYMORPHIC
+template <typename T, typename U = T, typename... Us>
+auto make_polymorphic(Us&&... us) -> polymorphic<T> {
+  return polymorphic<T>(std::in_place_type<U>, std::forward<Us>(us)...);
+}
 
+template <typename T, typename U = T, typename A, typename... Us>
+auto allocate_polymorphic(A a, Us&&... us) -> polymorphic<T, A> {
+  return polymorphic<T, A>(std::allocator_arg, a, std::in_place_type<U>,
+                           std::forward<Us>(us)...);
+}
+#endif  // XYZ_HAS_EXTENSION_MAKE_POLYMORPHIC
 }  // namespace xyz
 
 #endif  // XYZ_POLYMORPHIC_H_

polymorphic_test.cc

@@ -845,4 +845,61 @@ TEST(PolymorphicTest, TaggedAllocatorsNotEqualMoveConstructFromValueless) {
   EXPECT_TRUE(iii.valueless_after_move());
 }
 
+#ifdef XYZ_HAS_EXTENSION_MAKE_POLYMORPHIC
+TEST(PolymorphicTest, MakePolymorphicDerivedNoArgs) {
+  auto p = xyz::make_polymorphic<Derived>();
+  EXPECT_EQ(p->value(), 0);
+}
+
+TEST(PolymorphicTest, MakePolymorphicBaseDerivedNoArgs) {
+  auto p = xyz::make_polymorphic<Base, Derived>();
+  static_assert(std::is_same_v<decltype(p), xyz::polymorphic<Base>>);
+  EXPECT_EQ(p->value(), 0);
+}
+
+TEST(PolymorphicTest, MakePolymorphicDerived) {
+  auto p = xyz::make_polymorphic<Derived>(42);
+  EXPECT_EQ(p->value(), 42);
+}
+
+TEST(PolymorphicTest, MakePolymorphicBaseDerived) {
+  auto p = xyz::make_polymorphic<Base, Derived>(42);
+  static_assert(std::is_same_v<decltype(p), xyz::polymorphic<Base>>);
+  EXPECT_EQ(p->value(), 42);
+}
+
+TEST(PolymorphicTest, AllocatePolymorphicDerivedNoArgs) {
+  xyz::TaggedAllocator<Derived> a(1);
+  auto p = xyz::allocate_polymorphic<Derived>(a);
+  EXPECT_EQ(p->value(), 0);
+  EXPECT_EQ(p.get_allocator().tag, 1);
+}
+
+TEST(PolymorphicTest, AllocatePolymorphicBaseDerivedNoArgs) {
+  xyz::TaggedAllocator<Base> a(1);
+  auto p = xyz::allocate_polymorphic<Base, Derived>(a);
+  static_assert(
+      std::is_same_v<decltype(p),
+                     xyz::polymorphic<Base, xyz::TaggedAllocator<Base>>>);
+  EXPECT_EQ(p->value(), 0);
+  EXPECT_EQ(p.get_allocator().tag, 1);
+}
+
+TEST(PolymorphicTest, AllocatePolymorphicDerived) {
+  xyz::TaggedAllocator<Derived> a(1);
+  auto p = xyz::allocate_polymorphic<Derived>(a, 42);
+  EXPECT_EQ(p->value(), 42);
+  EXPECT_EQ(p.get_allocator().tag, 1);
+}
+
+TEST(PolymorphicTest, AllocatePolymorphicBaseDerived) {
+  xyz::TaggedAllocator<Derived> a(1);
+  auto p = xyz::allocate_polymorphic<Base, Derived>(a, 42);
+  static_assert(
+      std::is_same_v<decltype(p),
+                     xyz::polymorphic<Base, xyz::TaggedAllocator<Derived>>>);
+  EXPECT_EQ(p->value(), 42);
+  EXPECT_EQ(p.get_allocator().tag, 1);
+}
+#endif  // XYZ_HAS_EXTENSION_MAKE_POLYMORPHIC
 }  // namespace