diff options
Diffstat (limited to 'base')
| -rw-r--r-- | base/ref_counted.h | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/base/ref_counted.h b/base/ref_counted.h index e04bb7c..ea532a4 100644 --- a/base/ref_counted.h +++ b/base/ref_counted.h @@ -93,6 +93,21 @@ class RefCounted : public subtle::RefCountedBase { DISALLOW_COPY_AND_ASSIGN(RefCounted<T>); }; +// Forward declaration. +template <class T, typename Traits> class RefCountedThreadSafe; + +// Default traits for RefCountedThreadSafe<T>. Deletes the object when its ref +// count reaches 0. Overload to delete it on a different thread etc. +template<typename T> +struct DefaultRefCountedThreadSafeTraits { + static void Destruct(T* x) { + // Delete through RefCountedThreadSafe to make child classes only need to be + // friend with RefCountedThreadSafe instead of this struct, which is an + // implementation detail. + RefCountedThreadSafe<T, DefaultRefCountedThreadSafeTraits>::DeleteInternal(x); + } +}; + // // A thread-safe variant of RefCounted<T> // @@ -100,7 +115,12 @@ class RefCounted : public subtle::RefCountedBase { // ... // }; // -template <class T> +// If you're using the default trait, then you may choose to add compile time +// asserts that no one else is deleting your object. i.e. +// private: +// friend struct base::RefCountedThreadSafe<MyFoo>; +// ~MyFoo(); +template <class T, typename Traits = DefaultRefCountedThreadSafeTraits<T> > class RefCountedThreadSafe : public subtle::RefCountedThreadSafeBase { public: RefCountedThreadSafe() { } @@ -112,12 +132,15 @@ class RefCountedThreadSafe : public subtle::RefCountedThreadSafeBase { void Release() { if (subtle::RefCountedThreadSafeBase::Release()) { - delete static_cast<T*>(this); + Traits::Destruct(static_cast<T*>(this)); } } private: - DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafe<T>); + friend struct DefaultRefCountedThreadSafeTraits<T>; + static void DeleteInternal(T* x) { delete x; } + + DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafe); }; // |