base/memory/raw_scoped_refptr_mismatch_checker.h

   1 // Copyright (c) 2011 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 BASE_MEMORY_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
   6 #define BASE_MEMORY_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "base/template_util.h"
  10 #include "base/tuple.h"
  11 #include "build/build_config.h"
  12
  13 // It is dangerous to post a task with a T* argument where T is a subtype of
  14 // RefCounted(Base|ThreadSafeBase), since by the time the parameter is used, the
  15 // object may already have been deleted since it was not held with a
  16 // scoped_refptr. Example: http://crbug.com/27191
  17 // The following set of traits are designed to generate a compile error
  18 // whenever this antipattern is attempted.
  19
  20 namespace base {
  21
  22 // This is a base internal implementation file used by task.h and callback.h.
  23 // Not for public consumption, so we wrap it in namespace internal.
  24 namespace internal {
  25
  26 template <typename T>
  27 struct NeedsScopedRefptrButGetsRawPtr {
  28 #if defined(OS_WIN)
  29   enum {
  30     value = base::false_type::value
  31   };
  32 #else
  33   enum {
  34     // Human readable translation: you needed to be a scoped_refptr if you are a
  35     // raw pointer type and are convertible to a RefCounted(Base|ThreadSafeBase)
  36     // type.
  37     value = (is_pointer<T>::value &&
  38              (is_convertible<T, subtle::RefCountedBase*>::value ||
  39               is_convertible<T, subtle::RefCountedThreadSafeBase*>::value))
  40   };
  41 #endif
  42 };
  43
  44 template <typename Params>
  45 struct ParamsUseScopedRefptrCorrectly {
  46   enum { value = 0 };
  47 };
  48
  49 template <>
  50 struct ParamsUseScopedRefptrCorrectly<Tuple0> {
  51   enum { value = 1 };
  52 };
  53
  54 template <typename A>
  55 struct ParamsUseScopedRefptrCorrectly<Tuple1<A> > {
  56   enum { value = !NeedsScopedRefptrButGetsRawPtr<A>::value };
  57 };
  58
  59 template <typename A, typename B>
  60 struct ParamsUseScopedRefptrCorrectly<Tuple2<A, B> > {
  61   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
  62                    NeedsScopedRefptrButGetsRawPtr<B>::value) };
  63 };
  64
  65 template <typename A, typename B, typename C>
  66 struct ParamsUseScopedRefptrCorrectly<Tuple3<A, B, C> > {
  67   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
  68                    NeedsScopedRefptrButGetsRawPtr<B>::value ||
  69                    NeedsScopedRefptrButGetsRawPtr<C>::value) };
  70 };
  71
  72 template <typename A, typename B, typename C, typename D>
  73 struct ParamsUseScopedRefptrCorrectly<Tuple4<A, B, C, D> > {
  74   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
  75                    NeedsScopedRefptrButGetsRawPtr<B>::value ||
  76                    NeedsScopedRefptrButGetsRawPtr<C>::value ||
  77                    NeedsScopedRefptrButGetsRawPtr<D>::value) };
  78 };
  79
  80 template <typename A, typename B, typename C, typename D, typename E>
  81 struct ParamsUseScopedRefptrCorrectly<Tuple5<A, B, C, D, E> > {
  82   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
  83                    NeedsScopedRefptrButGetsRawPtr<B>::value ||
  84                    NeedsScopedRefptrButGetsRawPtr<C>::value ||
  85                    NeedsScopedRefptrButGetsRawPtr<D>::value ||
  86                    NeedsScopedRefptrButGetsRawPtr<E>::value) };
  87 };
  88
  89 template <typename A, typename B, typename C, typename D, typename E,
  90           typename F>
  91 struct ParamsUseScopedRefptrCorrectly<Tuple6<A, B, C, D, E, F> > {
  92   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
  93                    NeedsScopedRefptrButGetsRawPtr<B>::value ||
  94                    NeedsScopedRefptrButGetsRawPtr<C>::value ||
  95                    NeedsScopedRefptrButGetsRawPtr<D>::value ||
  96                    NeedsScopedRefptrButGetsRawPtr<E>::value ||
  97                    NeedsScopedRefptrButGetsRawPtr<F>::value) };
  98 };
  99
 100 template <typename A, typename B, typename C, typename D, typename E,
 101           typename F, typename G>
 102 struct ParamsUseScopedRefptrCorrectly<Tuple7<A, B, C, D, E, F, G> > {
 103   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
 104                    NeedsScopedRefptrButGetsRawPtr<B>::value ||
 105                    NeedsScopedRefptrButGetsRawPtr<C>::value ||
 106                    NeedsScopedRefptrButGetsRawPtr<D>::value ||
 107                    NeedsScopedRefptrButGetsRawPtr<E>::value ||
 108                    NeedsScopedRefptrButGetsRawPtr<F>::value ||
 109                    NeedsScopedRefptrButGetsRawPtr<G>::value) };
 110 };
 111
 112 template <typename A, typename B, typename C, typename D, typename E,
 113           typename F, typename G, typename H>
 114 struct ParamsUseScopedRefptrCorrectly<Tuple8<A, B, C, D, E, F, G, H> > {
 115   enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
 116                    NeedsScopedRefptrButGetsRawPtr<B>::value ||
 117                    NeedsScopedRefptrButGetsRawPtr<C>::value ||
 118                    NeedsScopedRefptrButGetsRawPtr<D>::value ||
 119                    NeedsScopedRefptrButGetsRawPtr<E>::value ||
 120                    NeedsScopedRefptrButGetsRawPtr<F>::value ||
 121                    NeedsScopedRefptrButGetsRawPtr<G>::value ||
 122                    NeedsScopedRefptrButGetsRawPtr<H>::value) };
 123 };
 124
 125 }  // namespace internal
 126
 127 }  // namespace base
 128
 129 #endif  // BASE_MEMORY_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_