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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*
* Copyright (C) 2009-2016, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
* file name: localpointer.h
* encoding: UTF-8
* tab size: 8 (not used)
* indentation:4
*
* created on: 2009nov13
* created by: Markus W. Scherer
*/
#ifndef __LOCALPOINTER_H__
#define __LOCALPOINTER_H__
/**
* \file
* \brief C++ API: "Smart pointers" for use with and in ICU4C C++ code.
*
* These classes are inspired by
* - std::auto_ptr
* - boost::scoped_ptr & boost::scoped_array
* - Taligent Safe Pointers (TOnlyPointerTo)
*
* but none of those provide for all of the goals for ICU smart pointers:
* - Smart pointer owns the object and releases it when it goes out of scope.
* - No transfer of ownership via copy/assignment to reduce misuse. Simpler & more robust.
* - ICU-compatible: No exceptions.
* - Need to be able to orphan/release the pointer and its ownership.
* - Need variants for normal C++ object pointers, C++ arrays, and ICU C service objects.
*
* For details see https://icu.unicode.org/design/cpp/scoped_ptr
*/
#include "unicode/utypes.h"
#if U_SHOW_CPLUSPLUS_API
#include <memory>
U_NAMESPACE_BEGIN
/**
* "Smart pointer" base class; do not use directly: use LocalPointer etc.
*
* Base class for smart pointer classes that do not throw exceptions.
*
* Do not use this base class directly, since it does not delete its pointer.
* A subclass must implement methods that delete the pointer:
* Destructor and adoptInstead().
*
* There is no operator T *() provided because the programmer must decide
* whether to use getAlias() (without transfer of ownership) or orphan()
* (with transfer of ownership and NULLing of the pointer).
*
* @see LocalPointer
* @see LocalArray
* @see U_DEFINE_LOCAL_OPEN_POINTER
* @stable ICU 4.4
*/
template<typename T>
class LocalPointerBase {
public:
// No heap allocation. Use only on the stack.
static void* U_EXPORT2 operator new(size_t) = delete;
static void* U_EXPORT2 operator new[](size_t) = delete;
#if U_HAVE_PLACEMENT_NEW
static void* U_EXPORT2 operator new(size_t, void*) = delete;
#endif
/**
* Constructor takes ownership.
* @param p simple pointer to an object that is adopted
* @stable ICU 4.4
*/
explicit LocalPointerBase(T *p=nullptr) : ptr(p) {}
/**
* Destructor deletes the object it owns.
* Subclass must override: Base class does nothing.
* @stable ICU 4.4
*/
~LocalPointerBase() { /* delete ptr; */ }
/**
* nullptr check.
* @return true if ==nullptr
* @stable ICU 4.4
*/
UBool isNull() const { return ptr==nullptr; }
/**
* nullptr check.
* @return true if !=nullptr
* @stable ICU 4.4
*/
UBool isValid() const { return ptr!=nullptr; }
/**
* Comparison with a simple pointer, so that existing code
* with ==nullptr need not be changed.
* @param other simple pointer for comparison
* @return true if this pointer value equals other
* @stable ICU 4.4
*/
bool operator==(const T *other) const { return ptr==other; }
/**
* Comparison with a simple pointer, so that existing code
* with !=nullptr need not be changed.
* @param other simple pointer for comparison
* @return true if this pointer value differs from other
* @stable ICU 4.4
*/
bool operator!=(const T *other) const { return ptr!=other; }
/**
* Access without ownership change.
* @return the pointer value
* @stable ICU 4.4
*/
T *getAlias() const { return ptr; }
/**
* Access without ownership change.
* @return the pointer value as a reference
* @stable ICU 4.4
*/
T &operator*() const { return *ptr; }
/**
* Access without ownership change.
* @return the pointer value
* @stable ICU 4.4
*/
T *operator->() const { return ptr; }
/**
* Gives up ownership; the internal pointer becomes nullptr.
* @return the pointer value;
* caller becomes responsible for deleting the object
* @stable ICU 4.4
*/
T *orphan() {
T *p=ptr;
ptr=nullptr;
return p;
}
/**
* Deletes the object it owns,
* and adopts (takes ownership of) the one passed in.
* Subclass must override: Base class does not delete the object.
* @param p simple pointer to an object that is adopted
* @stable ICU 4.4
*/
void adoptInstead(T *p) {
// delete ptr;
ptr=p;
}
protected:
/**
* Actual pointer.
* @internal
*/
T *ptr;
private:
// No comparison operators with other LocalPointerBases.
bool operator==(const LocalPointerBase<T> &other);
bool operator!=(const LocalPointerBase<T> &other);
// No ownership sharing: No copy constructor, no assignment operator.
LocalPointerBase(const LocalPointerBase<T> &other);
void operator=(const LocalPointerBase<T> &other);
};
/**
* "Smart pointer" class, deletes objects via the standard C++ delete operator.
* For most methods see the LocalPointerBase base class.
*
* Usage example:
* \code
* LocalPointer<UnicodeString> s(new UnicodeString((UChar32)0x50005));
* int32_t length=s->length(); // 2
* char16_t lead=s->charAt(0); // 0xd900
* if(some condition) { return; } // no need to explicitly delete the pointer
* s.adoptInstead(new UnicodeString((char16_t)0xfffc));
* length=s->length(); // 1
* // no need to explicitly delete the pointer
* \endcode
*
* @see LocalPointerBase
* @stable ICU 4.4
*/
template<typename T>
class LocalPointer : public LocalPointerBase<T> {
public:
using LocalPointerBase<T>::operator*;
using LocalPointerBase<T>::operator->;
/**
* Constructor takes ownership.
* @param p simple pointer to an object that is adopted
* @stable ICU 4.4
*/
explicit LocalPointer(T *p=nullptr) : LocalPointerBase<T>(p) {}
/**
* Constructor takes ownership and reports an error if nullptr.
*
* This constructor is intended to be used with other-class constructors
* that may report a failure UErrorCode,
* so that callers need to check only for U_FAILURE(errorCode)
* and not also separately for isNull().
*
* @param p simple pointer to an object that is adopted
* @param errorCode in/out UErrorCode, set to U_MEMORY_ALLOCATION_ERROR
* if p==nullptr and no other failure code had been set
* @stable ICU 55
*/
LocalPointer(T *p, UErrorCode &errorCode) : LocalPointerBase<T>(p) {
if(p==nullptr && U_SUCCESS(errorCode)) {
errorCode=U_MEMORY_ALLOCATION_ERROR;
}
}
/**
* Move constructor, leaves src with isNull().
* @param src source smart pointer
* @stable ICU 56
*/
LocalPointer(LocalPointer<T> &&src) noexcept : LocalPointerBase<T>(src.ptr) {
src.ptr=nullptr;
}
/**
* Constructs a LocalPointer from a C++11 std::unique_ptr.
* The LocalPointer steals the object owned by the std::unique_ptr.
*
* This constructor works via move semantics. If your std::unique_ptr is
* in a local variable, you must use std::move.
*
* @param p The std::unique_ptr from which the pointer will be stolen.
* @stable ICU 64
*/
explicit LocalPointer(std::unique_ptr<T> &&p)
: LocalPointerBase<T>(p.release()) {}
/**
* Destructor deletes the object it owns.
* @stable ICU 4.4
*/
~LocalPointer() {
delete LocalPointerBase<T>::ptr;
}
/**
* Move assignment operator, leaves src with isNull().
* The behavior is undefined if *this and src are the same object.
* @param src source smart pointer
* @return *this
* @stable ICU 56
*/
LocalPointer<T> &operator=(LocalPointer<T> &&src) noexcept {
delete LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=src.ptr;
src.ptr=nullptr;
return *this;
}
/**
* Move-assign from an std::unique_ptr to this LocalPointer.
* Steals the pointer from the std::unique_ptr.
*
* @param p The std::unique_ptr from which the pointer will be stolen.
* @return *this
* @stable ICU 64
*/
LocalPointer<T> &operator=(std::unique_ptr<T> &&p) noexcept {
adoptInstead(p.release());
return *this;
}
/**
* Swap pointers.
* @param other other smart pointer
* @stable ICU 56
*/
void swap(LocalPointer<T> &other) noexcept {
T *temp=LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=other.ptr;
other.ptr=temp;
}
/**
* Non-member LocalPointer swap function.
* @param p1 will get p2's pointer
* @param p2 will get p1's pointer
* @stable ICU 56
*/
friend inline void swap(LocalPointer<T> &p1, LocalPointer<T> &p2) noexcept {
p1.swap(p2);
}
/**
* Deletes the object it owns,
* and adopts (takes ownership of) the one passed in.
* @param p simple pointer to an object that is adopted
* @stable ICU 4.4
*/
void adoptInstead(T *p) {
delete LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=p;
}
/**
* Deletes the object it owns,
* and adopts (takes ownership of) the one passed in.
*
* If U_FAILURE(errorCode), then the current object is retained and the new one deleted.
*
* If U_SUCCESS(errorCode) but the input pointer is nullptr,
* then U_MEMORY_ALLOCATION_ERROR is set,
* the current object is deleted, and nullptr is set.
*
* @param p simple pointer to an object that is adopted
* @param errorCode in/out UErrorCode, set to U_MEMORY_ALLOCATION_ERROR
* if p==nullptr and no other failure code had been set
* @stable ICU 55
*/
void adoptInsteadAndCheckErrorCode(T *p, UErrorCode &errorCode) {
if(U_SUCCESS(errorCode)) {
delete LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=p;
if(p==nullptr) {
errorCode=U_MEMORY_ALLOCATION_ERROR;
}
} else {
delete p;
}
}
/**
* Conversion operator to a C++11 std::unique_ptr.
* Disowns the object and gives it to the returned std::unique_ptr.
*
* This operator works via move semantics. If your LocalPointer is
* in a local variable, you must use std::move.
*
* @return An std::unique_ptr owning the pointer previously owned by this
* icu::LocalPointer.
* @stable ICU 64
*/
operator std::unique_ptr<T> () && {
return std::unique_ptr<T>(LocalPointerBase<T>::orphan());
}
};
/**
* "Smart pointer" class, deletes objects via the C++ array delete[] operator.
* For most methods see the LocalPointerBase base class.
* Adds operator[] for array item access.
*
* Usage example:
* \code
* LocalArray<UnicodeString> a(new UnicodeString[2]);
* a[0].append((char16_t)0x61);
* if(some condition) { return; } // no need to explicitly delete the array
* a.adoptInstead(new UnicodeString[4]);
* a[3].append((char16_t)0x62).append((char16_t)0x63).reverse();
* // no need to explicitly delete the array
* \endcode
*
* @see LocalPointerBase
* @stable ICU 4.4
*/
template<typename T>
class LocalArray : public LocalPointerBase<T> {
public:
using LocalPointerBase<T>::operator*;
using LocalPointerBase<T>::operator->;
/**
* Constructor takes ownership.
* @param p simple pointer to an array of T objects that is adopted
* @stable ICU 4.4
*/
explicit LocalArray(T *p=nullptr) : LocalPointerBase<T>(p) {}
/**
* Constructor takes ownership and reports an error if nullptr.
*
* This constructor is intended to be used with other-class constructors
* that may report a failure UErrorCode,
* so that callers need to check only for U_FAILURE(errorCode)
* and not also separately for isNull().
*
* @param p simple pointer to an array of T objects that is adopted
* @param errorCode in/out UErrorCode, set to U_MEMORY_ALLOCATION_ERROR
* if p==nullptr and no other failure code had been set
* @stable ICU 56
*/
LocalArray(T *p, UErrorCode &errorCode) : LocalPointerBase<T>(p) {
if(p==nullptr && U_SUCCESS(errorCode)) {
errorCode=U_MEMORY_ALLOCATION_ERROR;
}
}
/**
* Move constructor, leaves src with isNull().
* @param src source smart pointer
* @stable ICU 56
*/
LocalArray(LocalArray<T> &&src) noexcept : LocalPointerBase<T>(src.ptr) {
src.ptr=nullptr;
}
/**
* Constructs a LocalArray from a C++11 std::unique_ptr of an array type.
* The LocalPointer steals the array owned by the std::unique_ptr.
*
* This constructor works via move semantics. If your std::unique_ptr is
* in a local variable, you must use std::move.
*
* @param p The std::unique_ptr from which the array will be stolen.
* @stable ICU 64
*/
explicit LocalArray(std::unique_ptr<T[]> &&p)
: LocalPointerBase<T>(p.release()) {}
/**
* Destructor deletes the array it owns.
* @stable ICU 4.4
*/
~LocalArray() {
delete[] LocalPointerBase<T>::ptr;
}
/**
* Move assignment operator, leaves src with isNull().
* The behavior is undefined if *this and src are the same object.
* @param src source smart pointer
* @return *this
* @stable ICU 56
*/
LocalArray<T> &operator=(LocalArray<T> &&src) noexcept {
delete[] LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=src.ptr;
src.ptr=nullptr;
return *this;
}
/**
* Move-assign from an std::unique_ptr to this LocalPointer.
* Steals the array from the std::unique_ptr.
*
* @param p The std::unique_ptr from which the array will be stolen.
* @return *this
* @stable ICU 64
*/
LocalArray<T> &operator=(std::unique_ptr<T[]> &&p) noexcept {
adoptInstead(p.release());
return *this;
}
/**
* Swap pointers.
* @param other other smart pointer
* @stable ICU 56
*/
void swap(LocalArray<T> &other) noexcept {
T *temp=LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=other.ptr;
other.ptr=temp;
}
/**
* Non-member LocalArray swap function.
* @param p1 will get p2's pointer
* @param p2 will get p1's pointer
* @stable ICU 56
*/
friend inline void swap(LocalArray<T> &p1, LocalArray<T> &p2) noexcept {
p1.swap(p2);
}
/**
* Deletes the array it owns,
* and adopts (takes ownership of) the one passed in.
* @param p simple pointer to an array of T objects that is adopted
* @stable ICU 4.4
*/
void adoptInstead(T *p) {
delete[] LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=p;
}
/**
* Deletes the array it owns,
* and adopts (takes ownership of) the one passed in.
*
* If U_FAILURE(errorCode), then the current array is retained and the new one deleted.
*
* If U_SUCCESS(errorCode) but the input pointer is nullptr,
* then U_MEMORY_ALLOCATION_ERROR is set,
* the current array is deleted, and nullptr is set.
*
* @param p simple pointer to an array of T objects that is adopted
* @param errorCode in/out UErrorCode, set to U_MEMORY_ALLOCATION_ERROR
* if p==nullptr and no other failure code had been set
* @stable ICU 56
*/
void adoptInsteadAndCheckErrorCode(T *p, UErrorCode &errorCode) {
if(U_SUCCESS(errorCode)) {
delete[] LocalPointerBase<T>::ptr;
LocalPointerBase<T>::ptr=p;
if(p==nullptr) {
errorCode=U_MEMORY_ALLOCATION_ERROR;
}
} else {
delete[] p;
}
}
/**
* Array item access (writable).
* No index bounds check.
* @param i array index
* @return reference to the array item
* @stable ICU 4.4
*/
T &operator[](ptrdiff_t i) const { return LocalPointerBase<T>::ptr[i]; }
/**
* Conversion operator to a C++11 std::unique_ptr.
* Disowns the object and gives it to the returned std::unique_ptr.
*
* This operator works via move semantics. If your LocalPointer is
* in a local variable, you must use std::move.
*
* @return An std::unique_ptr owning the pointer previously owned by this
* icu::LocalPointer.
* @stable ICU 64
*/
operator std::unique_ptr<T[]> () && {
return std::unique_ptr<T[]>(LocalPointerBase<T>::orphan());
}
};
/**
* \def U_DEFINE_LOCAL_OPEN_POINTER
* "Smart pointer" definition macro, deletes objects via the closeFunction.
* Defines a subclass of LocalPointerBase which works just
* like LocalPointer<Type> except that this subclass will use the closeFunction
* rather than the C++ delete operator.
*
* Usage example:
* \code
* LocalUCaseMapPointer csm(ucasemap_open(localeID, options, &errorCode));
* utf8OutLength=ucasemap_utf8ToLower(csm.getAlias(),
* utf8Out, (int32_t)sizeof(utf8Out),
* utf8In, utf8InLength, &errorCode);
* if(U_FAILURE(errorCode)) { return; } // no need to explicitly delete the UCaseMap
* \endcode
*
* @see LocalPointerBase
* @see LocalPointer
* @stable ICU 4.4
*/
#define U_DEFINE_LOCAL_OPEN_POINTER(LocalPointerClassName, Type, closeFunction) \
class LocalPointerClassName : public LocalPointerBase<Type> { \
public: \
using LocalPointerBase<Type>::operator*; \
using LocalPointerBase<Type>::operator->; \
explicit LocalPointerClassName(Type *p=nullptr) : LocalPointerBase<Type>(p) {} \
LocalPointerClassName(LocalPointerClassName &&src) noexcept \
: LocalPointerBase<Type>(src.ptr) { \
src.ptr=nullptr; \
} \
/* TODO: Be agnostic of the deleter function signature from the user-provided std::unique_ptr? */ \
explicit LocalPointerClassName(std::unique_ptr<Type, decltype(&closeFunction)> &&p) \
: LocalPointerBase<Type>(p.release()) {} \
~LocalPointerClassName() { if (ptr != nullptr) { closeFunction(ptr); } } \
LocalPointerClassName &operator=(LocalPointerClassName &&src) noexcept { \
if (ptr != nullptr) { closeFunction(ptr); } \
LocalPointerBase<Type>::ptr=src.ptr; \
src.ptr=nullptr; \
return *this; \
} \
/* TODO: Be agnostic of the deleter function signature from the user-provided std::unique_ptr? */ \
LocalPointerClassName &operator=(std::unique_ptr<Type, decltype(&closeFunction)> &&p) { \
adoptInstead(p.release()); \
return *this; \
} \
void swap(LocalPointerClassName &other) noexcept { \
Type *temp=LocalPointerBase<Type>::ptr; \
LocalPointerBase<Type>::ptr=other.ptr; \
other.ptr=temp; \
} \
friend inline void swap(LocalPointerClassName &p1, LocalPointerClassName &p2) noexcept { \
p1.swap(p2); \
} \
void adoptInstead(Type *p) { \
if (ptr != nullptr) { closeFunction(ptr); } \
ptr=p; \
} \
operator std::unique_ptr<Type, decltype(&closeFunction)> () && { \
return std::unique_ptr<Type, decltype(&closeFunction)>(LocalPointerBase<Type>::orphan(), closeFunction); \
} \
}
U_NAMESPACE_END
#endif /* U_SHOW_CPLUSPLUS_API */
#endif /* __LOCALPOINTER_H__ */