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/*
*
* Copyright 2017 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#ifndef GRPC_CORE_LIB_GPRPP_REF_COUNTED_PTR_H
#define GRPC_CORE_LIB_GPRPP_REF_COUNTED_PTR_H
#include <grpc/support/port_platform.h>
#include <type_traits>
#include <utility>
#include "src/core/lib/gprpp/debug_location.h"
#include "src/core/lib/gprpp/memory.h"
namespace grpc_core {
// A smart pointer class for objects that provide IncrementRefCount() and
// Unref() methods, such as those provided by the RefCounted base class.
template <typename T>
class RefCountedPtr {
public:
RefCountedPtr() {}
RefCountedPtr(std::nullptr_t) {}
// If value is non-null, we take ownership of a ref to it.
template <typename Y>
explicit RefCountedPtr(Y* value) {
value_ = value;
}
// Move ctors.
RefCountedPtr(RefCountedPtr&& other) {
value_ = other.value_;
other.value_ = nullptr;
}
template <typename Y>
RefCountedPtr(RefCountedPtr<Y>&& other) {
value_ = other.value_;
other.value_ = nullptr;
}
// Move assignment.
RefCountedPtr& operator=(RefCountedPtr&& other) {
reset(other.value_);
other.value_ = nullptr;
return *this;
}
template <typename Y>
RefCountedPtr& operator=(RefCountedPtr<Y>&& other) {
reset(other.value_);
other.value_ = nullptr;
return *this;
}
// Copy ctors.
RefCountedPtr(const RefCountedPtr& other) {
if (other.value_ != nullptr) other.value_->IncrementRefCount();
value_ = other.value_;
}
template <typename Y>
RefCountedPtr(const RefCountedPtr<Y>& other) {
static_assert(std::has_virtual_destructor<T>::value,
"T does not have a virtual dtor");
if (other.value_ != nullptr) other.value_->IncrementRefCount();
value_ = other.value_;
}
// Copy assignment.
RefCountedPtr& operator=(const RefCountedPtr& other) {
// Note: Order of reffing and unreffing is important here in case value_
// and other.value_ are the same object.
if (other.value_ != nullptr) other.value_->IncrementRefCount();
reset(other.value_);
return *this;
}
template <typename Y>
RefCountedPtr& operator=(const RefCountedPtr<Y>& other) {
static_assert(std::has_virtual_destructor<T>::value,
"T does not have a virtual dtor");
// Note: Order of reffing and unreffing is important here in case value_
// and other.value_ are the same object.
if (other.value_ != nullptr) other.value_->IncrementRefCount();
reset(other.value_);
return *this;
}
~RefCountedPtr() {
if (value_ != nullptr) value_->Unref();
}
// If value is non-null, we take ownership of a ref to it.
void reset(T* value = nullptr) {
if (value_ != nullptr) value_->Unref();
value_ = value;
}
void reset(const DebugLocation& location, const char* reason,
T* value = nullptr) {
if (value_ != nullptr) value_->Unref(location, reason);
value_ = value;
}
template <typename Y>
void reset(Y* value = nullptr) {
static_assert(std::has_virtual_destructor<T>::value,
"T does not have a virtual dtor");
if (value_ != nullptr) value_->Unref();
value_ = value;
}
template <typename Y>
void reset(const DebugLocation& location, const char* reason,
Y* value = nullptr) {
static_assert(std::has_virtual_destructor<T>::value,
"T does not have a virtual dtor");
if (value_ != nullptr) value_->Unref(location, reason);
value_ = value;
}
// TODO(roth): This method exists solely as a transition mechanism to allow
// us to pass a ref to idiomatic C code that does not use RefCountedPtr<>.
// Once all of our code has been converted to idiomatic C++, this
// method should go away.
T* release() {
T* value = value_;
value_ = nullptr;
return value;
}
T* get() const { return value_; }
T& operator*() const { return *value_; }
T* operator->() const { return value_; }
template <typename Y>
bool operator==(const RefCountedPtr<Y>& other) const {
return value_ == other.value_;
}
template <typename Y>
bool operator==(const Y* other) const {
return value_ == other;
}
bool operator==(std::nullptr_t) const { return value_ == nullptr; }
template <typename Y>
bool operator!=(const RefCountedPtr<Y>& other) const {
return value_ != other.value_;
}
template <typename Y>
bool operator!=(const Y* other) const {
return value_ != other;
}
bool operator!=(std::nullptr_t) const { return value_ != nullptr; }
private:
template <typename Y>
friend class RefCountedPtr;
T* value_ = nullptr;
};
template <typename T, typename... Args>
inline RefCountedPtr<T> MakeRefCounted(Args&&... args) {
return RefCountedPtr<T>(New<T>(std::forward<Args>(args)...));
}
} // namespace grpc_core
#endif /* GRPC_CORE_LIB_GPRPP_REF_COUNTED_PTR_H */
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