1 // Copyright (c) 2011 Google Inc. All rights reserved. 2 // 3 // Redistribution and use in source and binary forms, with or without 4 // modification, are permitted provided that the following conditions are 5 // met: 6 // 7 // * Redistributions of source code must retain the above copyright 8 // notice, this list of conditions and the following disclaimer. 9 // * Redistributions in binary form must reproduce the above 10 // copyright notice, this list of conditions and the following disclaimer 11 // in the documentation and/or other materials provided with the 12 // distribution. 13 // * Neither the name of Google Inc. nor the name Chromium Embedded 14 // Framework nor the names of its contributors may be used to endorse 15 // or promote products derived from this software without specific prior 16 // written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // Do not include this header file directly. Use base/cef_callback.h instead. 31 32 #ifndef CEF_INCLUDE_BASE_INTERNAL_CEF_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_ 33 #define CEF_INCLUDE_BASE_INTERNAL_CEF_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_ 34 35 #include <type_traits> 36 37 #include "include/base/cef_template_util.h" 38 39 // It is dangerous to post a task with a T* argument where T is a subtype of 40 // RefCounted(Base|ThreadSafeBase), since by the time the parameter is used, the 41 // object may already have been deleted since it was not held with a 42 // scoped_refptr. Example: http://crbug.com/27191 43 // The following set of traits are designed to generate a compile error 44 // whenever this antipattern is attempted. 45 46 namespace base { 47 48 // This is a base internal implementation file used by task.h and callback.h. 49 // Not for public consumption, so we wrap it in namespace internal. 50 namespace internal { 51 52 template <typename T, typename = void> 53 struct IsRefCountedType : std::false_type {}; 54 55 template <typename T> 56 struct IsRefCountedType<T, 57 void_t<decltype(std::declval<T*>()->AddRef()), 58 decltype(std::declval<T*>()->Release())>> 59 : std::true_type {}; 60 61 // Human readable translation: you needed to be a scoped_refptr if you are a raw 62 // pointer type and are convertible to a RefCounted(Base|ThreadSafeBase) type. 63 template <typename T> 64 struct NeedsScopedRefptrButGetsRawPtr 65 : conjunction<std::is_pointer<T>, 66 IsRefCountedType<std::remove_pointer_t<T>>> { 67 static_assert(!std::is_reference<T>::value, 68 "NeedsScopedRefptrButGetsRawPtr requires non-reference type."); 69 }; 70 71 } // namespace internal 72 73 } // namespace base 74 75 #endif // CEF_INCLUDE_BASE_INTERNAL_CEF_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_ 76