diff options
Diffstat (limited to 'upb/refcounted.h')
-rw-r--r-- | upb/refcounted.h | 111 |
1 files changed, 110 insertions, 1 deletions
diff --git a/upb/refcounted.h b/upb/refcounted.h index aaa2f60..54c1127 100644 --- a/upb/refcounted.h +++ b/upb/refcounted.h @@ -31,7 +31,10 @@ /* #define UPB_DEBUG_REFS */ #ifdef __cplusplus -namespace upb { class RefCounted; } +namespace upb { +class RefCounted; +template <class T> class reffed_ptr; +} #endif UPB_DECLARE_TYPE(upb::RefCounted, upb_refcounted) @@ -99,6 +102,7 @@ struct upb_refcounted { }; #ifdef UPB_DEBUG_REFS +extern upb_alloc upb_alloc_debugrefs; #define UPB_REFCOUNT_INIT(refs, ref2s) \ {&static_refcount, NULL, NULL, 0, true, refs, ref2s} #else @@ -235,4 +239,109 @@ inline void RefCounted::CheckRef(const void *owner) const { } /* namespace upb */ #endif + +/* upb::reffed_ptr ************************************************************/ + +#ifdef __cplusplus + +#include <algorithm> /* For std::swap(). */ + +/* Provides RAII semantics for upb refcounted objects. Each reffed_ptr owns a + * ref on whatever object it points to (if any). */ +template <class T> class upb::reffed_ptr { + public: + reffed_ptr() : ptr_(NULL) {} + + /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */ + template <class U> + reffed_ptr(U* val, const void* ref_donor = NULL) + : ptr_(upb::upcast(val)) { + if (ref_donor) { + assert(ptr_); + ptr_->DonateRef(ref_donor, this); + } else if (ptr_) { + ptr_->Ref(this); + } + } + + template <class U> + reffed_ptr(const reffed_ptr<U>& other) + : ptr_(upb::upcast(other.get())) { + if (ptr_) ptr_->Ref(this); + } + + reffed_ptr(const reffed_ptr& other) + : ptr_(upb::upcast(other.get())) { + if (ptr_) ptr_->Ref(this); + } + + ~reffed_ptr() { if (ptr_) ptr_->Unref(this); } + + template <class U> + reffed_ptr& operator=(const reffed_ptr<U>& other) { + reset(other.get()); + return *this; + } + + reffed_ptr& operator=(const reffed_ptr& other) { + reset(other.get()); + return *this; + } + + /* TODO(haberman): add C++11 move construction/assignment for greater + * efficiency. */ + + void swap(reffed_ptr& other) { + if (ptr_ == other.ptr_) { + return; + } + + if (ptr_) ptr_->DonateRef(this, &other); + if (other.ptr_) other.ptr_->DonateRef(&other, this); + std::swap(ptr_, other.ptr_); + } + + T& operator*() const { + assert(ptr_); + return *ptr_; + } + + T* operator->() const { + assert(ptr_); + return ptr_; + } + + T* get() const { return ptr_; } + + /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */ + template <class U> + void reset(U* ptr = NULL, const void* ref_donor = NULL) { + reffed_ptr(ptr, ref_donor).swap(*this); + } + + template <class U> + reffed_ptr<U> down_cast() { + return reffed_ptr<U>(upb::down_cast<U*>(get())); + } + + template <class U> + reffed_ptr<U> dyn_cast() { + return reffed_ptr<U>(upb::dyn_cast<U*>(get())); + } + + /* Plain release() is unsafe; if we were the only owner, it would leak the + * object. Instead we provide this: */ + T* ReleaseTo(const void* new_owner) { + T* ret = NULL; + ptr_->DonateRef(this, new_owner); + std::swap(ret, ptr_); + return ret; + } + + private: + T* ptr_; +}; + +#endif /* __cplusplus */ + #endif /* UPB_REFCOUNT_H_ */ |