swig/Examples/test-suite/cpp11_move_only_valuewrapper.i
William S Fulton bf36bf7d8a Movable and move-only types supported in "out" typemaps.
Enhance SWIGTYPE "out" typemaps to use std::move when copying
objects, thereby making use of move semantics when wrapping a function returning
by value if the returned type supports move semantics.

Wrapping functions that return move only types 'by value' now work out the box
without having to provide custom typemaps.

The implementation removed all casts in the "out" typemaps to allow the compiler to
appropriately choose calling a move constructor, where possible, otherwise a copy
constructor. The implementation alsoand required modifying SwigValueWrapper to
change a cast operator from:

  SwigValueWrapper::operator T&() const;

to

  #if __cplusplus >=201103L
    SwigValueWrapper::operator T&&() const;
  #else
    SwigValueWrapper::operator T&() const;
  #endif

This is not backwards compatible for C++11 and later when using the valuewrapper feature
if a cast is explicitly being made in user supplied "out" typemaps. Suggested change
in custom "out" typemaps for C++11 and later code:

1. Try remove the cast altogether to let the compiler use an appropriate implicit cast.
2. Change the cast, for example, from static_cast<X &> to static_cast<X &&>, using the
   __cplusplus macro if all versions of C++ need to be supported.

Issue #999
Closes #1044

More about the commit:
Added some missing "varout" typemaps for Ocaml which was falling back to
use "out" typemaps as they were missing.

Ruby std::set fix for SwigValueWrapper C++11 changes.
2022-06-30 17:26:48 +01:00

184 lines
4.9 KiB
OpenEdge ABL

%module cpp11_move_only_valuewrapper
/*
* This test case checks SwigValueWrapper and move assignment.
* Although not necessary, the test case was developed testing with C++98 compatibility for comparing improvements.
* C++11 and later is of course required for the move assignment support.
* C++98 is not actually necesary now as the test-suite only runs this test with compilers that support C++11 and later.
*/
%{
#include <iostream>
#include <sstream>
using std::cout;
using std::endl;
#if __cplusplus >= 201103L
#include <memory>
#else
namespace std {
// just something that will compile and vaguely work for when c++11 is not supported
template <class T> class unique_ptr {
T *ptr;
public:
unique_ptr(T *ptr = 0) : ptr(ptr) {}
unique_ptr(const unique_ptr &a) : ptr(a.ptr) { /*please look away*/ const_cast<unique_ptr &>(a).ptr = 0;}
~unique_ptr() { delete ptr; }
unique_ptr& operator=(const unique_ptr &a) {
if (&a != this) {
delete ptr;
ptr = a.ptr;
/*please look away*/ const_cast<unique_ptr &>(a).ptr = 0;
}
return *this;
}
};
}
#endif
%}
#if defined(SWIGD)
%rename(trace) debug;
#endif
%include "cpp11_move_only_helper.i"
%valuewrapper XXX;
%ignore XXX::operator=;
%inline %{
bool debug = false;
struct XXX {
XXX(int i = 0) { if (debug) cout << "XXX(" << i << ")" << " " << this << endl; Counter::normal_constructor++; }
XXX(const XXX &other) { if (debug) cout << "XXX(const XXX &)" << " " << this << " " << &other << endl; Counter::copy_constructor++;}
XXX & operator=(const XXX &other) { if (debug) cout << "operator=(const XXX &)" << " " << this << " " << &other << endl; Counter::copy_assignment++; return *this; }
#if defined(__cplusplus) && __cplusplus >= 201103L
XXX(XXX &&other) noexcept { if (debug) cout << "XXX(XXX &&)" << " " << this << endl; Counter::move_constructor++; }
XXX & operator=(XXX &&other) noexcept { if (debug) cout << "operator=(XXX &&)" << " " << this << endl; Counter::move_assignment++; return *this; }
#endif
~XXX() { if (debug) cout << "~XXX()" << " " << this << endl; Counter::destructor++; }
};
bool has_cplusplus11() {
#if __cplusplus >= 201103L
return true;
#else
return false;
#endif
}
%}
std::unique_ptr<XXX> makeUniqueXXX();
void cleanup(std::unique_ptr<XXX>* p);
%{
std::unique_ptr<XXX> makeUniqueXXX() {
if (debug) cout << "makeUniqueXXX()" << endl;
return std::unique_ptr<XXX>(new XXX(11));
}
void cleanup(std::unique_ptr<XXX>* p) {
delete p;
}
typedef XXX UUU;
%}
%inline %{
XXX createXXX() {
if (debug) cout << "createXXX()" << endl;
return XXX(111);
}
XXX createXXX2() {
if (debug) cout << "createXXX2()" << endl;
return XXX(222);
}
UUU createUnknownType() {
if (debug) cout << "createXXX2()" << endl;
return XXX(222);
}
struct YYY {};
void inputByValue(UUU uuu, XXX xxx, YYY yyy) {}
%}
%catches(std::string) test1;
%catches(std::string) test2;
%catches(std::string) test3;
%catches(std::string) test4;
%catches(std::string) test5;
%catches(std::string) test6;
%inline %{
// 'unit tests' for SwigValueWrapper
void test1() {
Counter::reset_counts();
{
SwigValueWrapper<XXX> x;
x = XXX();
}
#if __cplusplus >= 201103L
Counter::check_counts(1, 0, 0, 1, 0, 2); // was same as < c++11 counts below before move assignment operator added to SwigValueWrapper
#else
Counter::check_counts(1, 1, 0, 0, 0, 2);
#endif
}
void test2() {
Counter::reset_counts();
{
SwigValueWrapper<XXX> x;
x = XXX();
x = XXX();
}
#if __cplusplus >= 201103L
Counter::check_counts(2, 0, 0, 2, 0, 4);
#else
Counter::check_counts(2, 2, 0, 0, 0, 4);
#endif
}
void test3() {
Counter::reset_counts();
{
SwigValueWrapper<XXX> x;
XXX a(999);
#if __cplusplus >= 201103L
x = std::move(a);
#endif
}
#if __cplusplus >= 201103L
Counter::check_counts(1, 0, 0, 1, 0, 2);
#endif
}
void test4() {
Counter::reset_counts();
{
SwigValueWrapper<std::unique_ptr<XXX> > x;
x = std::unique_ptr<XXX>(new XXX(444));
}
Counter::check_counts(1, 0, 0, 0, 0, 1);
}
void test5() {
#if __cplusplus >= 201103L
Counter::reset_counts();
{
SwigValueWrapper<std::unique_ptr<XXX> > x;
x = std::unique_ptr<XXX>(new XXX(550));
std::unique_ptr<XXX> x2(new XXX(555));
x = std::move(x2);
}
Counter::check_counts(2, 0, 0, 0, 0, 2);
#endif
}
void test6() {
#if __cplusplus >= 201103L
Counter::reset_counts();
{
// emulates how std::unique_ptr typemaps could be wrapped with SwigValueWrapper
void *ptr = 0;
SwigValueWrapper<std::unique_ptr<XXX> > x; // SWIG generated if std::unique_ptr<> definition not parsed
x = makeUniqueXXX(); // SWIG generated code wrapping function returning std::unique_ptr
ptr = new std::unique_ptr<XXX>(x); // 'out' typemap (move std::unique_ptr from stack to the heap)
delete (std::unique_ptr<XXX> *)ptr; // Final cleanup (user needs to call this)
}
Counter::check_counts(1, 0, 0, 0, 0, 1);
#endif
}
%}