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
20namespace 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.
24namespace internal {
25
26template <typename T>
27struct 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
44template <typename Params>
45struct ParamsUseScopedRefptrCorrectly {
46  enum { value = 0 };
47};
48
49template <>
50struct ParamsUseScopedRefptrCorrectly<Tuple0> {
51  enum { value = 1 };
52};
53
54template <typename A>
55struct ParamsUseScopedRefptrCorrectly<Tuple1<A> > {
56  enum { value = !NeedsScopedRefptrButGetsRawPtr<A>::value };
57};
58
59template <typename A, typename B>
60struct ParamsUseScopedRefptrCorrectly<Tuple2<A, B> > {
61  enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
62                   NeedsScopedRefptrButGetsRawPtr<B>::value) };
63};
64
65template <typename A, typename B, typename C>
66struct ParamsUseScopedRefptrCorrectly<Tuple3<A, B, C> > {
67  enum { value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
68                   NeedsScopedRefptrButGetsRawPtr<B>::value ||
69                   NeedsScopedRefptrButGetsRawPtr<C>::value) };
70};
71
72template <typename A, typename B, typename C, typename D>
73struct 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
80template <typename A, typename B, typename C, typename D, typename E>
81struct 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
89template <typename A, typename B, typename C, typename D, typename E,
90          typename F>
91struct 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
100template <typename A, typename B, typename C, typename D, typename E,
101          typename F, typename G>
102struct 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
112template <typename A, typename B, typename C, typename D, typename E,
113          typename F, typename G, typename H>
114struct 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_
130