[DevTools] Compatibility with old STL libraries

third_party/WebKit/Source/platform/inspector_protocol/PlatformSTL.h

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PlatformSTL_h
 #define PlatformSTL_h
 
 #include <memory>
 
 #define PLATFORM_EXPORT
@@ skipping 104 matching lines @@
     static_assert(sizeof(T) < 0, "do not use array with size as type");
 };
 
 template <typename T> class unique_ptr {
 public:
     typedef typename remove_extent<T>::type ValueType;
     typedef ValueType* PtrType;
 
     unique_ptr() : m_ptr(nullptr) {}
     unique_ptr(std::nullptr_t) : m_ptr(nullptr) {}
+    unique_ptr(const unique_ptr&);
     unique_ptr(unique_ptr&&);
     template <typename U, typename = typename enable_if<is_convertible<U*, T*>::value>::type> unique_ptr(unique_ptr<U>&&);
 
     ~unique_ptr()
     {
         OwnedPtrDeleter<T>::deletePtr(m_ptr);
         m_ptr = nullptr;
     }
 
     PtrType get() const { return m_ptr; }
 
     void reset(PtrType = nullptr);
     PtrType release();
 
     ValueType& operator*() const { DCHECK(m_ptr); return *m_ptr; }
     PtrType operator->() const { DCHECK(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; }
 
     unique_ptr& operator=(std::nullptr_t) { reset(); return *this; }
 
-
+    unique_ptr& operator=(const unique_ptr&);
     unique_ptr& operator=(unique_ptr&&);
     template <typename U> unique_ptr& operator=(unique_ptr<U>&&);
 
     void swap(unique_ptr& o) { std::swap(m_ptr, o.m_ptr); }
 
     static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
 
     explicit unique_ptr(PtrType ptr) : m_ptr(ptr) {}
 
 private:
+    PtrType internalRelease() const

[pfeldman, 2016/07/15 23:14:07]

How is this different from release()

[eostroukhov-old, 2016/07/15 23:45:53]

This is an ugly hack - this method is actually const, allowing "copying" from a
const reference.

+    {
+        PtrType ptr = m_ptr;
+        m_ptr = nullptr;
+        return ptr;
+    }
 
     // We should never have two unique_ptrs for the same underlying object
     // (otherwise we'll get double-destruction), so these equality operators
     // should never be needed.
     template <typename U> bool operator==(const unique_ptr<U>&) const
     {
         static_assert(!sizeof(U*), "unique_ptrs should never be equal");
         return false;
     }
     template <typename U> bool operator!=(const unique_ptr<U>&) const
     {
         static_assert(!sizeof(U*), "unique_ptrs should never be equal");
         return false;
     }
 
-    PtrType m_ptr;
+    mutable PtrType m_ptr;
 };
 
 
 template <typename T> inline void unique_ptr<T>::reset(PtrType ptr)
 {
     PtrType p = m_ptr;
     m_ptr = ptr;
     OwnedPtrDeleter<T>::deletePtr(p);
 }
 
 template <typename T> inline typename unique_ptr<T>::PtrType unique_ptr<T>::release()
 {
     PtrType ptr = m_ptr;
     m_ptr = nullptr;
     return ptr;
 }
 
 template <typename T> inline typename unique_ptr<T>::ValueType& unique_ptr<T>::operator[](std::ptrdiff_t i) const
 {
     static_assert(is_array<T>::value, "elements access is possible for arrays only");
     DCHECK(m_ptr);
     DCHECK_GE(i, 0);
     return m_ptr[i];
 }
 
+template <typename T> inline unique_ptr<T>::unique_ptr(const unique_ptr<T>& o)
+    : m_ptr(o.internalRelease())
+{
+}
+
 template <typename T> inline unique_ptr<T>::unique_ptr(unique_ptr<T>&& o)
     : m_ptr(o.release())
 {
 }
 
 template <typename T>
 template <typename U, typename> inline unique_ptr<T>::unique_ptr(unique_ptr<U>&& o)
     : m_ptr(o.release())
 {
     static_assert(!is_array<T>::value, "pointers to array must never be converted");
 }
 
+template <typename T> inline unique_ptr<T>& unique_ptr<T>::operator=(const unique_ptr<T>& o)
+{
+    PtrType ptr = m_ptr;

[pfeldman, 2016/07/15 23:14:07]

Looks like the same code as below, reuse?

[eostroukhov-old, 2016/07/15 23:45:53]

Done.

+    m_ptr = o.internalRelease();
+    DCHECK(!ptr || m_ptr != ptr);
+    OwnedPtrDeleter<T>::deletePtr(ptr);
+
+    return *this;
+}
+
 template <typename T> inline unique_ptr<T>& unique_ptr<T>::operator=(unique_ptr<T>&& o)
 {
     PtrType ptr = m_ptr;
     m_ptr = o.release();
     DCHECK(!ptr || m_ptr != ptr);
     OwnedPtrDeleter<T>::deletePtr(ptr);
 
     return *this;
 }
 
@@ skipping 49 matching lines @@
 
 #endif // defined(__APPLE__) && !defined(_LIBCPP_VERSION)
 
 template <typename T>
 std::unique_ptr<T> wrapUnique(T* ptr)
 {
     return std::unique_ptr<T>(ptr);
 }
 
 #endif // PlatformSTL_h