third_party/WebKit/public/platform/WebPassOwnPtr.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef WebPassOwnPtr_h
   6 #define WebPassOwnPtr_h
   7
   8 #include "public/platform/WebCommon.h"
   9
  10 #if INSIDE_BLINK
  11 #include "wtf/PassOwnPtr.h"
  12 #endif
  13
  14 namespace blink {
  15
  16 // WebPassOwnPtr<T> is used to pass a T pointer with ownership from chromium
  17 // side to blink side. T's definition must be shared among all users
  18 // (especially between chromium and blink).
  19 // TODO(yhirano): Migrate to scoped_ptr or std::unique_ptr once the repository
  20 // merge is done or C++11 std library is allowed.
  21 template <typename T>
  22 class WebPassOwnPtr final {
  23 public:
  24     WebPassOwnPtr() : m_ptr(nullptr) {}
  25     WebPassOwnPtr(decltype(nullptr)) : m_ptr(nullptr) {}
  26     // We need |const| to bind an rvalue. As a result, |m_ptr| needs to be
  27     // mutable because we manipulate it.
  28     template <typename U>
  29     WebPassOwnPtr(const WebPassOwnPtr<U>& o)
  30     {
  31         m_ptr = o.m_ptr;
  32         o.m_ptr = nullptr;
  33     }
  34     WebPassOwnPtr(const WebPassOwnPtr& o)
  35     {
  36         m_ptr = o.m_ptr;
  37         o.m_ptr = nullptr;
  38     }
  39     ~WebPassOwnPtr()
  40     {
  41         delete m_ptr;
  42     }
  43     WebPassOwnPtr& operator =(const WebPassOwnPtr&) = delete;
  44
  45 #if INSIDE_BLINK
  46     PassOwnPtr<T> release()
  47     {
  48         T* ptr = m_ptr;
  49         m_ptr = nullptr;
  50         return adoptPtr(ptr);
  51     }
  52 #endif // INSIDE_BLINK
  53
  54     template <typename U> friend class WebPassOwnPtr;
  55     template <typename U> friend WebPassOwnPtr<U> adoptWebPtr(U*);
  56
  57 private:
  58     explicit WebPassOwnPtr(T* ptr) : m_ptr(ptr) {}
  59
  60     // See the constructor comment to see why |mutable| is needed.
  61     mutable T* m_ptr;
  62 };
  63
  64 template <typename T>
  65 WebPassOwnPtr<T> adoptWebPtr(T* p) { return WebPassOwnPtr<T>(p); }
  66
  67 } // namespace blink
  68
  69 #endif