+#if __cplusplus >= 201402L || __cpp_lib_make_unique >= 201304L || \
+ (__ANDROID__ && __cplusplus >= 201300L) || _MSC_VER >= 1900
+
+/* using override */ using std::make_unique;
+
+#else
+
+template <typename T, typename... Args>
+typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
+make_unique(Args&&... args) {
+ return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
+}
+
+// Allows 'make_unique<T[]>(10)'. (N3690 s20.9.1.4 p3-4)
+template <typename T>
+typename std::enable_if<std::is_array<T>::value, std::unique_ptr<T>>::type
+make_unique(const size_t n) {
+ return std::unique_ptr<T>(new typename std::remove_extent<T>::type[n]());
+}
+
+// Disallows 'make_unique<T[10]>()'. (N3690 s20.9.1.4 p5)
+template <typename T, typename... Args>
+typename std::enable_if<
+ std::extent<T>::value != 0, std::unique_ptr<T>>::type
+make_unique(Args&&...) = delete;
+
+#endif
+
+/**
+ * static_function_deleter
+ *
+ * So you can write this:
+ *
+ * using RSA_deleter = folly::static_function_deleter<RSA, &RSA_free>;
+ * auto rsa = std::unique_ptr<RSA, RSA_deleter>(RSA_new());
+ * RSA_generate_key_ex(rsa.get(), bits, exponent, nullptr);
+ * rsa = nullptr; // calls RSA_free(rsa.get())
+ *
+ * This would be sweet as well for BIO, but unfortunately BIO_free has signature
+ * int(BIO*) while we require signature void(BIO*). So you would need to make a
+ * wrapper for it:
+ *
+ * inline void BIO_free_fb(BIO* bio) { CHECK_EQ(1, BIO_free(bio)); }
+ * using BIO_deleter = folly::static_function_deleter<BIO, &BIO_free_fb>;
+ * auto buf = std::unique_ptr<BIO, BIO_deleter>(BIO_new(BIO_s_mem()));
+ * buf = nullptr; // calls BIO_free(buf.get())
+ */
+
+template <typename T, void(*f)(T*)>
+struct static_function_deleter {
+ void operator()(T* t) const {
+ f(t);
+ }
+};
+
+/**
+ * to_shared_ptr
+ *
+ * Convert unique_ptr to shared_ptr without specifying the template type
+ * parameter and letting the compiler deduce it.
+ *
+ * So you can write this:
+ *
+ * auto sptr = to_shared_ptr(getSomethingUnique<T>());
+ *
+ * Instead of this:
+ *
+ * auto sptr = shared_ptr<T>(getSomethingUnique<T>());
+ *
+ * Useful when `T` is long, such as:
+ *
+ * using T = foobar::FooBarAsyncClient;
+ */
+template <typename T, typename D>
+std::shared_ptr<T> to_shared_ptr(std::unique_ptr<T, D>&& ptr) {
+ return std::shared_ptr<T>(std::move(ptr));
+}
+
+/**
+ * to_weak_ptr
+ *
+ * Make a weak_ptr and return it from a shared_ptr without specifying the
+ * template type parameter and letting the compiler deduce it.
+ *
+ * So you can write this:
+ *
+ * auto wptr = to_weak_ptr(getSomethingShared<T>());
+ *
+ * Instead of this:
+ *
+ * auto wptr = weak_ptr<T>(getSomethingShared<T>());
+ *
+ * Useful when `T` is long, such as:
+ *
+ * using T = foobar::FooBarAsyncClient;
+ */
+template <typename T>
+std::weak_ptr<T> to_weak_ptr(const std::shared_ptr<T>& ptr) {
+ return std::weak_ptr<T>(ptr);
+}
+
+struct SysBufferDeleter {
+ void operator()(void* p) const {
+ ::free(p);
+ }
+};
+
+using SysBufferUniquePtr = std::unique_ptr<void, SysBufferDeleter>;
+inline SysBufferUniquePtr allocate_sys_buffer(size_t size) {
+ return SysBufferUniquePtr(::malloc(size));