src/include/base/internal/cef_raw_scoped_refptr_mismatch_checker.h

// Copyright (c) 2011 Google Inc. All rights reserved.
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// Do not include this header file directly. Use base/cef_callback.h instead.

#ifndef CEF_INCLUDE_BASE_INTERNAL_CEF_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
#define CEF_INCLUDE_BASE_INTERNAL_CEF_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_

#include "include/base/cef_build.h"
#include "include/base/cef_ref_counted.h"
#include "include/base/cef_template_util.h"
#include "include/base/cef_tuple.h"

// It is dangerous to post a task with a T* argument where T is a subtype of
// RefCounted(Base|ThreadSafeBase), since by the time the parameter is used, the
// object may already have been deleted since it was not held with a
// scoped_refptr. Example: http://crbug.com/27191
// The following set of traits are designed to generate a compile error
// whenever this antipattern is attempted.

namespace base {

namespace cef_internal {

template <typename T>
struct NeedsScopedRefptrButGetsRawPtr {
#if defined(OS_WIN)
  enum { value = base::false_type::value };
#else
  enum {
    // Human readable translation: you needed to be a scoped_refptr if you are a
    // raw pointer type and are convertible to a RefCounted(Base|ThreadSafeBase)
    // type.
    value = (is_pointer<T>::value &&
             (is_convertible<T, subtle::RefCountedBase*>::value ||
              is_convertible<T, subtle::RefCountedThreadSafeBase*>::value))
  };
#endif
};

template <typename Params>
struct ParamsUseScopedRefptrCorrectly {
  enum { value = 0 };
};

template <>
struct ParamsUseScopedRefptrCorrectly<Tuple0> {
  enum { value = 1 };
};

template <typename A>
struct ParamsUseScopedRefptrCorrectly<Tuple1<A>> {
  enum { value = !NeedsScopedRefptrButGetsRawPtr<A>::value };
};

template <typename A, typename B>
struct ParamsUseScopedRefptrCorrectly<Tuple2<A, B>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value)
  };
};

template <typename A, typename B, typename C>
struct ParamsUseScopedRefptrCorrectly<Tuple3<A, B, C>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value ||
              NeedsScopedRefptrButGetsRawPtr<C>::value)
  };
};

template <typename A, typename B, typename C, typename D>
struct ParamsUseScopedRefptrCorrectly<Tuple4<A, B, C, D>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value ||
              NeedsScopedRefptrButGetsRawPtr<C>::value ||
              NeedsScopedRefptrButGetsRawPtr<D>::value)
  };
};

template <typename A, typename B, typename C, typename D, typename E>
struct ParamsUseScopedRefptrCorrectly<Tuple5<A, B, C, D, E>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value ||
              NeedsScopedRefptrButGetsRawPtr<C>::value ||
              NeedsScopedRefptrButGetsRawPtr<D>::value ||
              NeedsScopedRefptrButGetsRawPtr<E>::value)
  };
};

template <typename A,
          typename B,
          typename C,
          typename D,
          typename E,
          typename F>
struct ParamsUseScopedRefptrCorrectly<Tuple6<A, B, C, D, E, F>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value ||
              NeedsScopedRefptrButGetsRawPtr<C>::value ||
              NeedsScopedRefptrButGetsRawPtr<D>::value ||
              NeedsScopedRefptrButGetsRawPtr<E>::value ||
              NeedsScopedRefptrButGetsRawPtr<F>::value)
  };
};

template <typename A,
          typename B,
          typename C,
          typename D,
          typename E,
          typename F,
          typename G>
struct ParamsUseScopedRefptrCorrectly<Tuple7<A, B, C, D, E, F, G>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value ||
              NeedsScopedRefptrButGetsRawPtr<C>::value ||
              NeedsScopedRefptrButGetsRawPtr<D>::value ||
              NeedsScopedRefptrButGetsRawPtr<E>::value ||
              NeedsScopedRefptrButGetsRawPtr<F>::value ||
              NeedsScopedRefptrButGetsRawPtr<G>::value)
  };
};

template <typename A,
          typename B,
          typename C,
          typename D,
          typename E,
          typename F,
          typename G,
          typename H>
struct ParamsUseScopedRefptrCorrectly<Tuple8<A, B, C, D, E, F, G, H>> {
  enum {
    value = !(NeedsScopedRefptrButGetsRawPtr<A>::value ||
              NeedsScopedRefptrButGetsRawPtr<B>::value ||
              NeedsScopedRefptrButGetsRawPtr<C>::value ||
              NeedsScopedRefptrButGetsRawPtr<D>::value ||
              NeedsScopedRefptrButGetsRawPtr<E>::value ||
              NeedsScopedRefptrButGetsRawPtr<F>::value ||
              NeedsScopedRefptrButGetsRawPtr<G>::value ||
              NeedsScopedRefptrButGetsRawPtr<H>::value)
  };
};

}  // namespace cef_internal

}  // namespace base

#endif  // CEF_INCLUDE_BASE_INTERNAL_CEF_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_