webrtc中的rtc::MakeUnique

rtc::MakeUnique：

在简单封装了一下，创建std::unique_ptr；

源码在src\rtc_base\ptr_util.h中；

namespace rtc {


// Helper to transfer ownership of a raw pointer to a std::unique_ptr.
// Note that std::unique_ptr has very different semantics from
// std::unique_ptr: do not use this helper for array allocations.
template
std::unique_ptr WrapUnique(T* ptr) {
  return std::unique_ptr(ptr);
}


namespace internal {


template
struct MakeUniqueResult {
  using Scalar = std::unique_ptr;
};


template
struct MakeUniqueResult {
  using Array = std::unique_ptr;
};


template
struct MakeUniqueResult {
  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(args) should be preferred over WrapUnique(new T(args)): bare
// calls to `new` should be treated with scrutiny.
//
// Usage:
//   // ptr is a std::unique_ptr
//   auto ptr = MakeUnique("hello world!");
//
//   // arr is a std::unique_ptr
//   auto arr = MakeUnique(5);


// Overload for non-array types. Arguments are forwarded to T's constructor.
template
typename internal::MakeUniqueResult::Scalar MakeUnique(Args&&... args) {
  return std::unique_ptr(new T(std::forward(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 internal::MakeUniqueResult::Array MakeUnique(size_t size) {
  return std::unique_ptr(new typename std::remove_extent::type[size]());
}


// Overload to reject array types of known bound, e.g. T[n].
template
typename internal::MakeUniqueResult::Invalid MakeUnique(Args&&... args) =
    delete;