WTF: Make PassOwnPtr<T> move-only.

third_party/WebKit/Source/wtf/OwnPtr.h

 /*
  *  Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *  Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Library General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
@@ skipping 25 matching lines @@
 template <typename T> class OwnPtr {
     USING_FAST_MALLOC(OwnPtr);
     WTF_MAKE_NONCOPYABLE(OwnPtr);
 public:
     typedef typename std::remove_extent<T>::type ValueType;
     typedef ValueType* PtrType;
 
     OwnPtr() : m_ptr(nullptr) {}
     OwnPtr(std::nullptr_t) : m_ptr(nullptr) {}
 
-    // See comment in PassOwnPtr.h for why this takes a const reference.
-    OwnPtr(const PassOwnPtr<T>&);
-    template <typename U> OwnPtr(const PassOwnPtr<U>&, EnsurePtrConvertibleArgDecl(U, T));
+    OwnPtr(PassOwnPtr<T>&&);
+    template <typename U> OwnPtr(PassOwnPtr<U>&&, EnsurePtrConvertibleArgDecl(U, T));
 
     // Hash table deleted values, which are only constructed and never copied or
     // destroyed.
     OwnPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) {}
     bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
 
     ~OwnPtr()
     {
         OwnedPtrDeleter<T>::deletePtr(m_ptr);
         m_ptr = nullptr;
     }
 
     PtrType get() const { return m_ptr; }
 
     void clear();
     PassOwnPtr<T> release();
     PtrType leakPtr() WARN_UNUSED_RETURN;
 
     ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
     PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
 
     ValueType& operator[](std::ptrdiff_t i) const;
 
     bool operator!() const { return !m_ptr; }
     explicit operator bool() const { return m_ptr; }
 
-    OwnPtr& operator=(const PassOwnPtr<T>&);
+    OwnPtr& operator=(PassOwnPtr<T>&&);
     OwnPtr& operator=(std::nullptr_t) { clear(); return *this; }
-    template <typename U> OwnPtr& operator=(const PassOwnPtr<U>&);
+    template <typename U> OwnPtr& operator=(PassOwnPtr<U>&&);
 
     OwnPtr(OwnPtr&&);
     template <typename U> OwnPtr(OwnPtr<U>&&);
 
     OwnPtr& operator=(OwnPtr&&);
     template <typename U> OwnPtr& operator=(OwnPtr<U>&&);
 
     void swap(OwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
 
     static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
@@ skipping 19 matching lines @@
     }
     template <typename U> bool operator!=(const PassOwnPtr<U>&) const
     {
         static_assert(!sizeof(U*), "OwnPtrs should never be equal");
         return false;
     }
 
     PtrType m_ptr;
 };
 
-template <typename T> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<T>& o)
+template <typename T> inline OwnPtr<T>::OwnPtr(PassOwnPtr<T>&& o)
     : m_ptr(o.leakPtr())
 {
 }
 
 template <typename T>
-template <typename U> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<U>& o, EnsurePtrConvertibleArgDefn(U, T))
+template <typename U> inline OwnPtr<T>::OwnPtr(PassOwnPtr<U>&& o, EnsurePtrConvertibleArgDefn(U, T))
     : m_ptr(o.leakPtr())
 {
     static_assert(!std::is_array<T>::value, "pointers to array must never be converted");
 }
 
 template <typename T> inline void OwnPtr<T>::clear()
 {
     PtrType ptr = m_ptr;
     m_ptr = nullptr;
     OwnedPtrDeleter<T>::deletePtr(ptr);
@@ skipping 14 matching lines @@
 }
 
 template <typename T> inline typename OwnPtr<T>::ValueType& OwnPtr<T>::operator[](std::ptrdiff_t i) const
 {
     static_assert(std::is_array<T>::value, "elements access is possible for arrays only");
     ASSERT(m_ptr);
     ASSERT(i >= 0);
     return m_ptr[i];
 }
 
-template <typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<T>& o)
+template <typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(PassOwnPtr<T>&& o)
 {
     PtrType ptr = m_ptr;
     m_ptr = o.leakPtr();
     ASSERT(!ptr || m_ptr != ptr);
     OwnedPtrDeleter<T>::deletePtr(ptr);
     return *this;
 }
 
 template <typename T>
-template <typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<U>& o)
+template <typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(PassOwnPtr<U>&& o)
 {
     static_assert(!std::is_array<T>::value, "pointers to array must never be converted");
     PtrType ptr = m_ptr;
     m_ptr = o.leakPtr();
     ASSERT(!ptr || m_ptr != ptr);
     OwnedPtrDeleter<T>::deletePtr(ptr);
     return *this;
 }
 
 template <typename T> inline OwnPtr<T>::OwnPtr(OwnPtr<T>&& o)
@@ skipping 58 matching lines @@
 template <typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)
 {
     return p.get();
 }
 
 } // namespace WTF
 
 using WTF::OwnPtr;
 
 #endif // WTF_OwnPtr_h