mfbt/UniquePtr.h
author Dustin J. Mitchell <dustin@mozilla.com>
Wed, 07 Sep 2016 00:10:51 +0000
changeset 354971 1627fd341fc154d4fb771366676b7101204362df
parent 344338 96875d7ae6f2f4cb0f56cd872eaae90345933563
child 475080 b54db66223586b4e04f5cb926fccdacf8a176b91
permissions -rw-r--r--
Bug 1286075: allow optimization of tasks whose dependencies have not been optimized; r=armenzg MikeLing initially did this in bug 1287018. The intent of this conditional was to make optimization faster by not even checking most tasks, based on the assumption that if the prerequisite to a task has changed (for example, a docker image or a build), then naturally we will want to execute that task. However, as we have developed actual optimization methods, this has proven not to be the case: we might want to optimize a test out if its inputs have not changed, even if a new installer has been built. Similarly, SETA may optimize tasks out even if their inputs have changed. MozReview-Commit-ID: LgHET3Z84GB

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Smart pointer managing sole ownership of a resource. */

#ifndef mozilla_UniquePtr_h
#define mozilla_UniquePtr_h

#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/Compiler.h"
#include "mozilla/Move.h"
#include "mozilla/Pair.h"
#include "mozilla/TypeTraits.h"

namespace mozilla {

template<typename T> class DefaultDelete;
template<typename T, class D = DefaultDelete<T>> class UniquePtr;

} // namespace mozilla

namespace mozilla {

namespace detail {

struct HasPointerTypeHelper
{
  template <class U> static double Test(...);
  template <class U> static char Test(typename U::pointer* = 0);
};

template <class T>
class HasPointerType : public IntegralConstant<bool, sizeof(HasPointerTypeHelper::Test<T>(0)) == 1>
{
};

template <class T, class D, bool = HasPointerType<D>::value>
struct PointerTypeImpl
{
  typedef typename D::pointer Type;
};

template <class T, class D>
struct PointerTypeImpl<T, D, false>
{
  typedef T* Type;
};

template <class T, class D>
struct PointerType
{
  typedef typename PointerTypeImpl<T, typename RemoveReference<D>::Type>::Type Type;
};

} // namespace detail

/**
 * UniquePtr is a smart pointer that wholly owns a resource.  Ownership may be
 * transferred out of a UniquePtr through explicit action, but otherwise the
 * resource is destroyed when the UniquePtr is destroyed.
 *
 * UniquePtr is similar to C++98's std::auto_ptr, but it improves upon auto_ptr
 * in one crucial way: it's impossible to copy a UniquePtr.  Copying an auto_ptr
 * obviously *can't* copy ownership of its singly-owned resource.  So what
 * happens if you try to copy one?  Bizarrely, ownership is implicitly
 * *transferred*, preserving single ownership but breaking code that assumes a
 * copy of an object is identical to the original.  (This is why auto_ptr is
 * prohibited in STL containers.)
 *
 * UniquePtr solves this problem by being *movable* rather than copyable.
 * Instead of passing a |UniquePtr u| directly to the constructor or assignment
 * operator, you pass |Move(u)|.  In doing so you indicate that you're *moving*
 * ownership out of |u|, into the target of the construction/assignment.  After
 * the transfer completes, |u| contains |nullptr| and may be safely destroyed.
 * This preserves single ownership but also allows UniquePtr to be moved by
 * algorithms that have been made move-safe.  (Note: if |u| is instead a
 * temporary expression, don't use |Move()|: just pass the expression, because
 * it's already move-ready.  For more information see Move.h.)
 *
 * UniquePtr is also better than std::auto_ptr in that the deletion operation is
 * customizable.  An optional second template parameter specifies a class that
 * (through its operator()(T*)) implements the desired deletion policy.  If no
 * policy is specified, mozilla::DefaultDelete<T> is used -- which will either
 * |delete| or |delete[]| the resource, depending whether the resource is an
 * array.  Custom deletion policies ideally should be empty classes (no member
 * fields, no member fields in base classes, no virtual methods/inheritance),
 * because then UniquePtr can be just as efficient as a raw pointer.
 *
 * Use of UniquePtr proceeds like so:
 *
 *   UniquePtr<int> g1; // initializes to nullptr
 *   g1.reset(new int); // switch resources using reset()
 *   g1 = nullptr; // clears g1, deletes the int
 *
 *   UniquePtr<int> g2(new int); // owns that int
 *   int* p = g2.release(); // g2 leaks its int -- still requires deletion
 *   delete p; // now freed
 *
 *   struct S { int x; S(int x) : x(x) {} };
 *   UniquePtr<S> g3, g4(new S(5));
 *   g3 = Move(g4); // g3 owns the S, g4 cleared
 *   S* p = g3.get(); // g3 still owns |p|
 *   assert(g3->x == 5); // operator-> works (if .get() != nullptr)
 *   assert((*g3).x == 5); // also operator* (again, if not cleared)
 *   Swap(g3, g4); // g4 now owns the S, g3 cleared
 *   g3.swap(g4);  // g3 now owns the S, g4 cleared
 *   UniquePtr<S> g5(Move(g3)); // g5 owns the S, g3 cleared
 *   g5.reset(); // deletes the S, g5 cleared
 *
 *   struct FreePolicy { void operator()(void* p) { free(p); } };
 *   UniquePtr<int, FreePolicy> g6(static_cast<int*>(malloc(sizeof(int))));
 *   int* ptr = g6.get();
 *   g6 = nullptr; // calls free(ptr)
 *
 * Now, carefully note a few things you *can't* do:
 *
 *   UniquePtr<int> b1;
 *   b1 = new int; // BAD: can only assign another UniquePtr
 *   int* ptr = b1; // BAD: no auto-conversion to pointer, use get()
 *
 *   UniquePtr<int> b2(b1); // BAD: can't copy a UniquePtr
 *   UniquePtr<int> b3 = b1; // BAD: can't copy-assign a UniquePtr
 *
 * (Note that changing a UniquePtr to store a direct |new| expression is
 * permitted, but usually you should use MakeUnique, defined at the end of this
 * header.)
 *
 * A few miscellaneous notes:
 *
 * UniquePtr, when not instantiated for an array type, can be move-constructed
 * and move-assigned, not only from itself but from "derived" UniquePtr<U, E>
 * instantiations where U converts to T and E converts to D.  If you want to use
 * this, you're going to have to specify a deletion policy for both UniquePtr
 * instantations, and T pretty much has to have a virtual destructor.  In other
 * words, this doesn't work:
 *
 *   struct Base { virtual ~Base() {} };
 *   struct Derived : Base {};
 *
 *   UniquePtr<Base> b1;
 *   // BAD: DefaultDelete<Base> and DefaultDelete<Derived> don't interconvert
 *   UniquePtr<Derived> d1(Move(b));
 *
 *   UniquePtr<Base> b2;
 *   UniquePtr<Derived, DefaultDelete<Base>> d2(Move(b2)); // okay
 *
 * UniquePtr is specialized for array types.  Specializing with an array type
 * creates a smart-pointer version of that array -- not a pointer to such an
 * array.
 *
 *   UniquePtr<int[]> arr(new int[5]);
 *   arr[0] = 4;
 *
 * What else is different?  Deletion of course uses |delete[]|.  An operator[]
 * is provided.  Functionality that doesn't make sense for arrays is removed.
 * The constructors and mutating methods only accept array pointers (not T*, U*
 * that converts to T*, or UniquePtr<U[]> or UniquePtr<U>) or |nullptr|.
 *
 * It's perfectly okay for a function to return a UniquePtr. This transfers
 * the UniquePtr's sole ownership of the data, to the fresh UniquePtr created
 * in the calling function, that will then solely own that data. Such functions
 * can return a local variable UniquePtr, |nullptr|, |UniquePtr(ptr)| where
 * |ptr| is a |T*|, or a UniquePtr |Move()|'d from elsewhere.
 *
 * UniquePtr will commonly be a member of a class, with lifetime equivalent to
 * that of that class.  If you want to expose the related resource, you could
 * expose a raw pointer via |get()|, but ownership of a raw pointer is
 * inherently unclear.  So it's better to expose a |const UniquePtr&| instead.
 * This prohibits mutation but still allows use of |get()| when needed (but
 * operator-> is preferred).  Of course, you can only use this smart pointer as
 * long as the enclosing class instance remains live -- no different than if you
 * exposed the |get()| raw pointer.
 *
 * To pass a UniquePtr-managed resource as a pointer, use a |const UniquePtr&|
 * argument.  To specify an inout parameter (where the method may or may not
 * take ownership of the resource, or reset it), or to specify an out parameter
 * (where simply returning a |UniquePtr| isn't possible), use a |UniquePtr&|
 * argument.  To unconditionally transfer ownership of a UniquePtr
 * into a method, use a |UniquePtr| argument.  To conditionally transfer
 * ownership of a resource into a method, should the method want it, use a
 * |UniquePtr&&| argument.
 */
template<typename T, class D>
class UniquePtr
{
public:
  typedef T ElementType;
  typedef D DeleterType;
  typedef typename detail::PointerType<T, DeleterType>::Type Pointer;

private:
  Pair<Pointer, DeleterType> mTuple;

  Pointer& ptr() { return mTuple.first(); }
  const Pointer& ptr() const { return mTuple.first(); }

  DeleterType& del() { return mTuple.second(); }
  const DeleterType& del() const { return mTuple.second(); }

public:
  /**
   * Construct a UniquePtr containing |nullptr|.
   */
  constexpr UniquePtr()
    : mTuple(static_cast<Pointer>(nullptr), DeleterType())
  {
    static_assert(!IsPointer<D>::value, "must provide a deleter instance");
    static_assert(!IsReference<D>::value, "must provide a deleter instance");
  }

  /**
   * Construct a UniquePtr containing |aPtr|.
   */
  explicit UniquePtr(Pointer aPtr)
    : mTuple(aPtr, DeleterType())
  {
    static_assert(!IsPointer<D>::value, "must provide a deleter instance");
    static_assert(!IsReference<D>::value, "must provide a deleter instance");
  }

  UniquePtr(Pointer aPtr,
            typename Conditional<IsReference<D>::value,
                                 D,
                                 const D&>::Type aD1)
    : mTuple(aPtr, aD1)
  {}

  // If you encounter an error with MSVC10 about RemoveReference below, along
  // the lines that "more than one partial specialization matches the template
  // argument list": don't use UniquePtr<T, reference to function>!  Ideally
  // you should make deletion use the same function every time, using a
  // deleter policy:
  //
  //   // BAD, won't compile with MSVC10, deleter doesn't need to be a
  //   // variable at all
  //   typedef void (&FreeSignature)(void*);
  //   UniquePtr<int, FreeSignature> ptr((int*) malloc(sizeof(int)), free);
  //
  //   // GOOD, compiles with MSVC10, deletion behavior statically known and
  //   // optimizable
  //   struct DeleteByFreeing
  //   {
  //     void operator()(void* aPtr) { free(aPtr); }
  //   };
  //
  // If deletion really, truly, must be a variable: you might be able to work
  // around this with a deleter class that contains the function reference.
  // But this workaround is untried and untested, because variable deletion
  // behavior really isn't something you should use.
  UniquePtr(Pointer aPtr,
            typename RemoveReference<D>::Type&& aD2)
    : mTuple(aPtr, Move(aD2))
  {
    static_assert(!IsReference<D>::value,
                  "rvalue deleter can't be stored by reference");
  }

  UniquePtr(UniquePtr&& aOther)
    : mTuple(aOther.release(), Forward<DeleterType>(aOther.get_deleter()))
  {}

  MOZ_IMPLICIT
  UniquePtr(decltype(nullptr))
    : mTuple(nullptr, DeleterType())
  {
    static_assert(!IsPointer<D>::value, "must provide a deleter instance");
    static_assert(!IsReference<D>::value, "must provide a deleter instance");
  }

  template<typename U, class E>
  MOZ_IMPLICIT
  UniquePtr(UniquePtr<U, E>&& aOther,
            typename EnableIf<IsConvertible<typename UniquePtr<U, E>::Pointer,
                                            Pointer>::value &&
                              !IsArray<U>::value &&
                              (IsReference<D>::value
                               ? IsSame<D, E>::value
                               : IsConvertible<E, D>::value),
                              int>::Type aDummy = 0)
    : mTuple(aOther.release(), Forward<E>(aOther.get_deleter()))
  {
  }

  ~UniquePtr() { reset(nullptr); }

  UniquePtr& operator=(UniquePtr&& aOther)
  {
    reset(aOther.release());
    get_deleter() = Forward<DeleterType>(aOther.get_deleter());
    return *this;
  }

  template<typename U, typename E>
  UniquePtr& operator=(UniquePtr<U, E>&& aOther)
  {
    static_assert(IsConvertible<typename UniquePtr<U, E>::Pointer,
                                Pointer>::value,
                  "incompatible UniquePtr pointees");
    static_assert(!IsArray<U>::value,
                  "can't assign from UniquePtr holding an array");

    reset(aOther.release());
    get_deleter() = Forward<E>(aOther.get_deleter());
    return *this;
  }

  UniquePtr& operator=(decltype(nullptr))
  {
    reset(nullptr);
    return *this;
  }

  T& operator*() const { return *get(); }
  Pointer operator->() const
  {
    MOZ_ASSERT(get(), "dereferencing a UniquePtr containing nullptr");
    return get();
  }

  explicit operator bool() const { return get() != nullptr; }

  Pointer get() const { return ptr(); }

  DeleterType& get_deleter() { return del(); }
  const DeleterType& get_deleter() const { return del(); }

  MOZ_MUST_USE Pointer release()
  {
    Pointer p = ptr();
    ptr() = nullptr;
    return p;
  }

  void reset(Pointer aPtr = Pointer())
  {
    Pointer old = ptr();
    ptr() = aPtr;
    if (old != nullptr) {
      get_deleter()(old);
    }
  }

  void swap(UniquePtr& aOther)
  {
    mTuple.swap(aOther.mTuple);
  }

  UniquePtr(const UniquePtr& aOther) = delete; // construct using Move()!
  void operator=(const UniquePtr& aOther) = delete; // assign using Move()!
};

// In case you didn't read the comment by the main definition (you should!): the
// UniquePtr<T[]> specialization exists to manage array pointers.  It deletes
// such pointers using delete[], it will reject construction and modification
// attempts using U* or U[].  Otherwise it works like the normal UniquePtr.
template<typename T, class D>
class UniquePtr<T[], D>
{
public:
  typedef T* Pointer;
  typedef T ElementType;
  typedef D DeleterType;

private:
  Pair<Pointer, DeleterType> mTuple;

public:
  /**
   * Construct a UniquePtr containing nullptr.
   */
  constexpr UniquePtr()
    : mTuple(static_cast<Pointer>(nullptr), DeleterType())
  {
    static_assert(!IsPointer<D>::value, "must provide a deleter instance");
    static_assert(!IsReference<D>::value, "must provide a deleter instance");
  }

  /**
   * Construct a UniquePtr containing |aPtr|.
   */
  explicit UniquePtr(Pointer aPtr)
    : mTuple(aPtr, DeleterType())
  {
    static_assert(!IsPointer<D>::value, "must provide a deleter instance");
    static_assert(!IsReference<D>::value, "must provide a deleter instance");
  }

  // delete[] knows how to handle *only* an array of a single class type.  For
  // delete[] to work correctly, it must know the size of each element, the
  // fields and base classes of each element requiring destruction, and so on.
  // So forbid all overloads which would end up invoking delete[] on a pointer
  // of the wrong type.
  template<typename U>
  UniquePtr(U&& aU,
            typename EnableIf<IsPointer<U>::value &&
                              IsConvertible<U, Pointer>::value,
                              int>::Type aDummy = 0)
  = delete;

  UniquePtr(Pointer aPtr,
            typename Conditional<IsReference<D>::value,
                                 D,
                                 const D&>::Type aD1)
    : mTuple(aPtr, aD1)
  {}

  // If you encounter an error with MSVC10 about RemoveReference below, along
  // the lines that "more than one partial specialization matches the template
  // argument list": don't use UniquePtr<T[], reference to function>!  See the
  // comment by this constructor in the non-T[] specialization above.
  UniquePtr(Pointer aPtr,
            typename RemoveReference<D>::Type&& aD2)
    : mTuple(aPtr, Move(aD2))
  {
    static_assert(!IsReference<D>::value,
                  "rvalue deleter can't be stored by reference");
  }

  // Forbidden for the same reasons as stated above.
  template<typename U, typename V>
  UniquePtr(U&& aU, V&& aV,
            typename EnableIf<IsPointer<U>::value &&
                              IsConvertible<U, Pointer>::value,
                              int>::Type aDummy = 0)
  = delete;

  UniquePtr(UniquePtr&& aOther)
    : mTuple(aOther.release(), Forward<DeleterType>(aOther.get_deleter()))
  {}

  MOZ_IMPLICIT
  UniquePtr(decltype(nullptr))
    : mTuple(nullptr, DeleterType())
  {
    static_assert(!IsPointer<D>::value, "must provide a deleter instance");
    static_assert(!IsReference<D>::value, "must provide a deleter instance");
  }

  ~UniquePtr() { reset(nullptr); }

  UniquePtr& operator=(UniquePtr&& aOther)
  {
    reset(aOther.release());
    get_deleter() = Forward<DeleterType>(aOther.get_deleter());
    return *this;
  }

  UniquePtr& operator=(decltype(nullptr))
  {
    reset();
    return *this;
  }

  explicit operator bool() const { return get() != nullptr; }

  T& operator[](decltype(sizeof(int)) aIndex) const { return get()[aIndex]; }
  Pointer get() const { return mTuple.first(); }

  DeleterType& get_deleter() { return mTuple.second(); }
  const DeleterType& get_deleter() const { return mTuple.second(); }

  MOZ_MUST_USE Pointer release()
  {
    Pointer p = mTuple.first();
    mTuple.first() = nullptr;
    return p;
  }

  void reset(Pointer aPtr = Pointer())
  {
    Pointer old = mTuple.first();
    mTuple.first() = aPtr;
    if (old != nullptr) {
      mTuple.second()(old);
    }
  }

  void reset(decltype(nullptr))
  {
    Pointer old = mTuple.first();
    mTuple.first() = nullptr;
    if (old != nullptr) {
      mTuple.second()(old);
    }
  }

  template<typename U>
  void reset(U) = delete;

  void swap(UniquePtr& aOther) { mTuple.swap(aOther.mTuple); }

  UniquePtr(const UniquePtr& aOther) = delete; // construct using Move()!
  void operator=(const UniquePtr& aOther) = delete; // assign using Move()!
};

/**
 * A default deletion policy using plain old operator delete.
 *
 * Note that this type can be specialized, but authors should beware of the risk
 * that the specialization may at some point cease to match (either because it
 * gets moved to a different compilation unit or the signature changes). If the
 * non-specialized (|delete|-based) version compiles for that type but does the
 * wrong thing, bad things could happen.
 *
 * This is a non-issue for types which are always incomplete (i.e. opaque handle
 * types), since |delete|-ing such a type will always trigger a compilation
 * error.
 */
template<typename T>
class DefaultDelete
{
public:
  constexpr DefaultDelete() {}

  template<typename U>
  MOZ_IMPLICIT DefaultDelete(const DefaultDelete<U>& aOther,
                             typename EnableIf<mozilla::IsConvertible<U*, T*>::value,
                                               int>::Type aDummy = 0)
  {}

  void operator()(T* aPtr) const
  {
    static_assert(sizeof(T) > 0, "T must be complete");
    delete aPtr;
  }
};

/** A default deletion policy using operator delete[]. */
template<typename T>
class DefaultDelete<T[]>
{
public:
  constexpr DefaultDelete() {}

  void operator()(T* aPtr) const
  {
    static_assert(sizeof(T) > 0, "T must be complete");
    delete[] aPtr;
  }

  template<typename U>
  void operator()(U* aPtr) const = delete;
};

template<typename T, class D>
void
Swap(UniquePtr<T, D>& aX, UniquePtr<T, D>& aY)
{
  aX.swap(aY);
}

template<typename T, class D, typename U, class E>
bool
operator==(const UniquePtr<T, D>& aX, const UniquePtr<U, E>& aY)
{
  return aX.get() == aY.get();
}

template<typename T, class D, typename U, class E>
bool
operator!=(const UniquePtr<T, D>& aX, const UniquePtr<U, E>& aY)
{
  return aX.get() != aY.get();
}

template<typename T, class D>
bool
operator==(const UniquePtr<T, D>& aX, decltype(nullptr))
{
  return !aX;
}

template<typename T, class D>
bool
operator==(decltype(nullptr), const UniquePtr<T, D>& aX)
{
  return !aX;
}

template<typename T, class D>
bool
operator!=(const UniquePtr<T, D>& aX, decltype(nullptr))
{
  return bool(aX);
}

template<typename T, class D>
bool
operator!=(decltype(nullptr), const UniquePtr<T, D>& aX)
{
  return bool(aX);
}

// No operator<, operator>, operator<=, operator>= for now because simplicity.

namespace detail {

template<typename T>
struct UniqueSelector
{
  typedef UniquePtr<T> SingleObject;
};

template<typename T>
struct UniqueSelector<T[]>
{
  typedef UniquePtr<T[]> UnknownBound;
};

template<typename T, decltype(sizeof(int)) N>
struct UniqueSelector<T[N]>
{
  typedef UniquePtr<T[N]> KnownBound;
};

} // namespace detail

/**
 * MakeUnique is a helper function for allocating new'd objects and arrays,
 * returning a UniquePtr containing the resulting pointer.  The semantics of
 * MakeUnique<Type>(...) are as follows.
 *
 *   If Type is an array T[n]:
 *     Disallowed, deleted, no overload for you!
 *   If Type is an array T[]:
 *     MakeUnique<T[]>(size_t) is the only valid overload.  The pointer returned
 *     is as if by |new T[n]()|, which value-initializes each element.  (If T
 *     isn't a class type, this will zero each element.  If T is a class type,
 *     then roughly speaking, each element will be constructed using its default
 *     constructor.  See C++11 [dcl.init]p7 for the full gory details.)
 *   If Type is non-array T:
 *     The arguments passed to MakeUnique<T>(...) are forwarded into a
 *     |new T(...)| call, initializing the T as would happen if executing
 *     |T(...)|.
 *
 * There are various benefits to using MakeUnique instead of |new| expressions.
 *
 * First, MakeUnique eliminates use of |new| from code entirely.  If objects are
 * only created through UniquePtr, then (assuming all explicit release() calls
 * are safe, including transitively, and no type-safety casting funniness)
 * correctly maintained ownership of the UniquePtr guarantees no leaks are
 * possible.  (This pays off best if a class is only ever created through a
 * factory method on the class, using a private constructor.)
 *
 * Second, initializing a UniquePtr using a |new| expression requires repeating
 * the name of the new'd type, whereas MakeUnique in concert with the |auto|
 * keyword names it only once:
 *
 *   UniquePtr<char> ptr1(new char()); // repetitive
 *   auto ptr2 = MakeUnique<char>();   // shorter
 *
 * Of course this assumes the reader understands the operation MakeUnique
 * performs.  In the long run this is probably a reasonable assumption.  In the
 * short run you'll have to use your judgment about what readers can be expected
 * to know, or to quickly look up.
 *
 * Third, a call to MakeUnique can be assigned directly to a UniquePtr.  In
 * contrast you can't assign a pointer into a UniquePtr without using the
 * cumbersome reset().
 *
 *   UniquePtr<char> p;
 *   p = new char;           // ERROR
 *   p.reset(new char);      // works, but fugly
 *   p = MakeUnique<char>(); // preferred
 *
 * (And third, although not relevant to Mozilla: MakeUnique is exception-safe.
 * An exception thrown after |new T| succeeds will leak that memory, unless the
 * pointer is assigned to an object that will manage its ownership.  UniquePtr
 * ably serves this function.)
 */

template<typename T, typename... Args>
typename detail::UniqueSelector<T>::SingleObject
MakeUnique(Args&&... aArgs)
{
  return UniquePtr<T>(new T(Forward<Args>(aArgs)...));
}

template<typename T>
typename detail::UniqueSelector<T>::UnknownBound
MakeUnique(decltype(sizeof(int)) aN)
{
  typedef typename RemoveExtent<T>::Type ArrayType;
  return UniquePtr<T>(new ArrayType[aN]());
}

template<typename T, typename... Args>
typename detail::UniqueSelector<T>::KnownBound
MakeUnique(Args&&... aArgs) = delete;

} // namespace mozilla

#endif /* mozilla_UniquePtr_h */