skia2/include/private/SkUniquePtr.h
bungeman 221524de3b Start using <type_traits> and <utility> (C++11).
SkUtility.h and SkTLogic.h implement a number of type traits now
available through <type_traits> and <utility>. This removes SkUtility.h,
replacing it with <utility>, and moves a number of traits in
SkTLogic.h to use the std:: equivelents. This change only uses C++11
parts of the standard library; SkTLogic.h will continue to provide
C++14 and beyond for now in the skstd namespace.

The changes to SkTLogic.h are being done gradually so that safe changes
may be landed confidently, with more risky changes in the future.

Review URL: https://codereview.chromium.org/1561683002
2016-01-05 14:59:40 -08:00

398 lines
13 KiB
C++

/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkUniquePtr_DEFINED
#define SkUniquePtr_DEFINED
#include "SkTLogic.h"
#include <cstddef>
#include <utility>
namespace skstd {
template <typename T> struct default_delete {
/*constexpr*/ default_delete() /*noexcept*/ = default;
template <typename U, typename = enable_if_t<is_convertible<U*, T*>::value>>
default_delete(const default_delete<U>&) /*noexcept*/ {}
void operator()(T* obj) const {
static_assert(sizeof(T) > 0, "Deleting pointer to incomplete type!");
delete obj;
}
};
template <typename T> struct default_delete<T[]> {
/*constexpr*/ default_delete() /*noexcept*/ = default;
void operator()(T* obj) const {
static_assert(sizeof(T) > 0, "Deleting pointer to incomplete type!");
delete [] obj;
}
};
template <typename T, typename D = default_delete<T>> class unique_ptr {
// remove_reference_t<D>::pointer if that type exists, otherwise T*.
struct pointer_type_detector {
template <typename U> static typename U::pointer detector(typename U::pointer*);
template <typename U> static T* detector(...);
using type = decltype(detector<remove_reference_t<D>>(0));
};
public:
using pointer = typename pointer_type_detector::type;
using element_type = T;
using deleter_type = D;
private:
template <typename B, bool = is_empty<B>::value /*&& !is_final<B>::value*/>
struct compressed_base : private B {
/*constexpr*/ compressed_base() : B() {}
/*constexpr*/ compressed_base(const B& b) : B(b) {}
/*constexpr*/ compressed_base(B&& b) : B(std::move(b)) {}
/*constexpr*/ B& get() /*noexcept*/ { return *this; }
/*constexpr*/ B const& get() const /*noexcept*/ { return *this; }
void swap(compressed_base&) /*noexcept*/ { }
};
template <typename B> struct compressed_base<B, false> {
B fb;
/*constexpr*/ compressed_base() : B() {}
/*constexpr*/ compressed_base(const B& b) : fb(b) {}
/*constexpr*/ compressed_base(B&& b) : fb(std::move(b)) {}
/*constexpr*/ B& get() /*noexcept*/ { return fb; }
/*constexpr*/ B const& get() const /*noexcept*/ { return fb; }
void swap(compressed_base& that) /*noexcept*/ { SkTSwap(fb, that.fB); }
};
struct compressed_data : private compressed_base<deleter_type> {
pointer fPtr;
/*constexpr*/ compressed_data() : compressed_base<deleter_type>(), fPtr() {}
/*constexpr*/ compressed_data(const pointer& ptr, const deleter_type& d)
: compressed_base<deleter_type>(d), fPtr(ptr) {}
template <typename U1, typename U2, typename = enable_if_t<
is_convertible<U1, pointer>::value && is_convertible<U2, deleter_type>::value
>> /*constexpr*/ compressed_data(U1&& ptr, U2&& d)
: compressed_base<deleter_type>(std::forward<U2>(d)), fPtr(std::forward<U1>(ptr)) {}
/*constexpr*/ pointer& getPointer() /*noexcept*/ { return fPtr; }
/*constexpr*/ pointer const& getPointer() const /*noexcept*/ { return fPtr; }
/*constexpr*/ deleter_type& getDeleter() /*noexcept*/ {
return compressed_base<deleter_type>::get();
}
/*constexpr*/ deleter_type const& getDeleter() const /*noexcept*/ {
return compressed_base<deleter_type>::get();
}
void swap(compressed_data& that) /*noexcept*/ {
compressed_base<deleter_type>::swap(static_cast<compressed_base<deleter_type>>(that));
SkTSwap(fPtr, that.fPtr);
}
};
compressed_data data;
public:
/*constexpr*/ unique_ptr() /*noexcept*/ : data() {
static_assert(!is_pointer<deleter_type>::value, "Deleter is nullptr function pointer!");
}
/*constexpr*/ unique_ptr(std::nullptr_t) /*noexcept*/ : unique_ptr() { }
explicit unique_ptr(pointer ptr) /*noexcept*/ : data(ptr, deleter_type()) {
static_assert(!is_pointer<deleter_type>::value, "Deleter is nullptr function pointer!");
}
unique_ptr(pointer ptr,
conditional_t<is_reference<deleter_type>::value, deleter_type,const deleter_type&> d)
/*noexcept*/ : data(ptr, d)
{}
unique_ptr(pointer ptr, remove_reference_t<deleter_type>&& d) /*noexcept*/
: data(std::move(ptr), std::move(d))
{
static_assert(!is_reference<deleter_type>::value,
"Binding an rvalue reference deleter as an lvalue reference deleter is not allowed.");
}
unique_ptr(unique_ptr&& that) /*noexcept*/
: data(that.release(), std::forward<deleter_type>(that.get_deleter()))
{}
template <typename U, typename ThatD, typename = enable_if_t<
is_convertible<typename unique_ptr<U, ThatD>::pointer, pointer>::value &&
!is_array<U>::value &&
conditional_t<is_reference<D>::value, is_same<ThatD, D>, is_convertible<ThatD, D>>::value>>
unique_ptr(unique_ptr<U, ThatD>&& that) /*noexcept*/
: data(that.release(), std::forward<ThatD>(that.get_deleter()))
{}
~unique_ptr() /*noexcept*/ {
pointer& ptr = data.getPointer();
if (ptr != nullptr) {
get_deleter()(ptr);
}
ptr = pointer();
}
unique_ptr& operator=(unique_ptr&& that) /*noexcept*/ {
reset(that.release());
get_deleter() = std::forward<deleter_type>(that.get_deleter());
return *this;
}
template <typename U, typename ThatD> enable_if_t<
is_convertible<typename unique_ptr<U, ThatD>::pointer, pointer>::value &&
!is_array<U>::value,
unique_ptr&> operator=(unique_ptr<U, ThatD>&& that) /*noexcept*/ {
reset(that.release());
get_deleter() = std::forward<ThatD>(that.get_deleter());
return *this;
}
unique_ptr& operator=(std::nullptr_t) /*noexcept*/ {
reset();
return *this;
}
add_lvalue_reference_t<element_type> operator*() const {
SkASSERT(get() != pointer());
return *get();
}
pointer operator->() const /*noexcept*/ {
SkASSERT(get() != pointer());
return get();
}
pointer get() const /*noexcept*/ {
return data.getPointer();
}
deleter_type& get_deleter() /*noexcept*/ {
return data.getDeleter();
}
const deleter_type& get_deleter() const /*noexcept*/ {
return data.getDeleter();
}
//explicit operator bool() const noexcept {
bool is_attached() const /*noexcept*/ {
return get() == pointer() ? false : true;
}
pointer release() /*noexcept*/ {
pointer ptr = get();
data.getPointer() = pointer();
return ptr;
}
void reset(pointer ptr = pointer()) /*noexcept*/ {
SkTSwap(data.getPointer(), ptr);
if (ptr != pointer()) {
get_deleter()(ptr);
}
}
void swap(unique_ptr& that) /*noexcept*/ {
SkTSwap(data, that.data);
}
unique_ptr(const unique_ptr&) = delete;
unique_ptr& operator=(const unique_ptr&) = delete;
};
template <typename T, typename D> class unique_ptr<T[], D> {
// remove_reference_t<D>::pointer if that type exists, otherwise T*.
struct pointer_type_detector {
template <typename U> static typename U::pointer detector(typename U::pointer*);
template <typename U> static T* detector(...);
using type = decltype(detector<remove_reference_t<D>>(0));
};
public:
using pointer = typename pointer_type_detector::type;
using element_type = T;
using deleter_type = D;
private:
template <typename B, bool = is_empty<B>::value /*&& !is_final<B>::value*/>
struct compressed_base : private B {
/*constexpr*/ compressed_base() : B() {}
/*constexpr*/ compressed_base(const B& b) : B(b) {}
/*constexpr*/ compressed_base(B&& b) : B(std::move(b)) {}
/*constexpr*/ B& get() /*noexcept*/ { return *this; }
/*constexpr*/ B const& get() const /*noexcept*/ { return *this; }
void swap(compressed_base&) /*noexcept*/ { }
};
template <typename B> struct compressed_base<B, false> {
B fb;
/*constexpr*/ compressed_base() : B() {}
/*constexpr*/ compressed_base(const B& b) : fb(b) {}
/*constexpr*/ compressed_base(B&& b) : fb(std::move(b)) {}
/*constexpr*/ B& get() /*noexcept*/ { return fb; }
/*constexpr*/ B const& get() const /*noexcept*/ { return fb; }
void swap(compressed_base& that) /*noexcept*/ { SkTSwap(fb, that.fB); }
};
struct compressed_data : private compressed_base<deleter_type> {
pointer fPtr;
/*constexpr*/ compressed_data() : compressed_base<deleter_type>(), fPtr() {}
/*constexpr*/ compressed_data(const pointer& ptr, const deleter_type& d)
: compressed_base<deleter_type>(d), fPtr(ptr) {}
template <typename U1, typename U2, typename = enable_if_t<
is_convertible<U1, pointer>::value && is_convertible<U2, deleter_type>::value
>> /*constexpr*/ compressed_data(U1&& ptr, U2&& d)
: compressed_base<deleter_type>(std::forward<U2>(d)), fPtr(std::forward<U1>(ptr)) {}
/*constexpr*/ pointer& getPointer() /*noexcept*/ { return fPtr; }
/*constexpr*/ pointer const& getPointer() const /*noexcept*/ { return fPtr; }
/*constexpr*/ deleter_type& getDeleter() /*noexcept*/ {
return compressed_base<deleter_type>::get();
}
/*constexpr*/ deleter_type const& getDeleter() const /*noexcept*/ {
return compressed_base<deleter_type>::get();
}
void swap(compressed_data& that) /*noexcept*/ {
compressed_base<deleter_type>::swap(static_cast<compressed_base<deleter_type>>(that));
SkTSwap(fPtr, that.fPtr);
}
};
compressed_data data;
public:
/*constexpr*/ unique_ptr() /*noexcept*/ : data() {
static_assert(!is_pointer<deleter_type>::value, "Deleter is nullptr function pointer!");
}
/*constexpr*/ unique_ptr(std::nullptr_t) /*noexcept*/ : unique_ptr() { }
explicit unique_ptr(pointer ptr) /*noexcept*/ : data(ptr, deleter_type()) {
static_assert(!is_pointer<deleter_type>::value, "Deleter is nullptr function pointer!");
}
unique_ptr(pointer ptr,
conditional_t<is_reference<deleter_type>::value, deleter_type,const deleter_type&> d)
/*noexcept*/ : data(ptr, d)
{}
unique_ptr(pointer ptr, remove_reference_t<deleter_type>&& d) /*noexcept*/
: data(std::move(ptr), std::move(d))
{
static_assert(!is_reference<deleter_type>::value,
"Binding an rvalue reference deleter as an lvalue reference deleter is not allowed.");
}
unique_ptr(unique_ptr&& that) /*noexcept*/
: data(that.release(), std::forward<deleter_type>(that.get_deleter()))
{}
~unique_ptr() {
pointer& ptr = data.getPointer();
if (ptr != nullptr) {
get_deleter()(ptr);
}
ptr = pointer();
}
unique_ptr& operator=(unique_ptr&& that) /*noexcept*/ {
reset(that.release());
get_deleter() = std::forward<deleter_type>(that.get_deleter());
return *this;
}
unique_ptr& operator=(std::nullptr_t) /*noexcept*/ {
reset();
return *this;
}
add_lvalue_reference_t<element_type> operator[](size_t i) const {
SkASSERT(get() != pointer());
return get()[i];
}
pointer get() const /*noexcept*/ {
return data.getPointer();
}
deleter_type& get_deleter() /*noexcept*/ {
return data.getDeleter();
}
const deleter_type& get_deleter() const /*noexcept*/ {
return data.getDeleter();
}
//explicit operator bool() const noexcept {
bool is_attached() const /*noexcept*/ {
return get() == pointer() ? false : true;
}
pointer release() /*noexcept*/ {
pointer ptr = get();
data.getPointer() = pointer();
return ptr;
}
void reset(pointer ptr = pointer()) /*noexcept*/ {
SkTSwap(data.getPointer(), ptr);
if (ptr != pointer()) {
get_deleter()(ptr);
}
}
template <typename U> void reset(U*) = delete;
void swap(unique_ptr& that) /*noexcept*/ {
data.swap(that.data);
}
unique_ptr(const unique_ptr&) = delete;
unique_ptr& operator=(const unique_ptr&) = delete;
};
template <typename T, typename D>
inline void swap(unique_ptr<T, D>& a, unique_ptr<T, D>& b) /*noexcept*/ {
a.swap(b);
}
template <typename T, typename D, typename U, typename ThatD>
inline bool operator==(const unique_ptr<T, D>& a, const unique_ptr<U, ThatD>& b) {
return a.get() == b.get();
}
template <typename T, typename D>
inline bool operator==(const unique_ptr<T, D>& a, std::nullptr_t) /*noexcept*/ {
//return !a;
return !a.is_attached();
}
template <typename T, typename D>
inline bool operator==(std::nullptr_t, const unique_ptr<T, D>& b) /*noexcept*/ {
//return !b;
return !b.is_attached();
}
template <typename T, typename D, typename U, typename ThatD>
inline bool operator!=(const unique_ptr<T, D>& a, const unique_ptr<U, ThatD>& b) {
return a.get() != b.get();
}
template <typename T, typename D>
inline bool operator!=(const unique_ptr<T, D>& a, std::nullptr_t) /*noexcept*/ {
//return (bool)a;
return a.is_attached();
}
template <typename T, typename D>
inline bool operator!=(std::nullptr_t, const unique_ptr<T, D>& b) /*noexcept*/ {
//return (bool)b;
return b.is_attached();
}
} // namespace skstd
#endif