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swig -go: treat a nil argument as NULL

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Let Go code pass "nil" when calling a C++ function that accepts a
pointer to a class.  The Go "nil" will be treated as a C++ "nullptr".

Fixes #2203
This commit is contained in:
Ian Lance Taylor 2022-03-08 15:15:05 -08:00
commit 70d530adfc
4 changed files with 53 additions and 12 deletions
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4
Examples/test-suite/go/go_inout_runme.go
View file

@ -50,4 +50,8 @@ func main() {
fmt.Println("for c2.M got", pm, "want", want)
panic(pm)
}
c1 := go_inout.NewC1()
c2.M2(c1)
c2.M2(nil)
}

2
Examples/test-suite/go_inout.i
View file

@ -239,5 +239,7 @@ class C1 {
};
class C2 : public C1 {
public:
void M2(C1*) {}
};
%}

11
Lib/go/goruntime.swg
View file

@ -149,6 +149,17 @@ type _swig_fnptr *byte
type _swig_memberptr *byte
%}
/* Convert a Go interface value into a C++ pointer. */
%insert(go_header) %{
func getSwigcptr(v interface { Swigcptr() uintptr }) uintptr {
if v == nil {
return 0
}
return v.Swigcptr()
}
%}
/* For directors we need C++ to track a Go pointer. Since we can't
pass a Go pointer into C++, we use a map to track the pointers on
the Go side. */

48
Source/Modules/go.cxx
View file

@ -1262,9 +1262,15 @@ private:
String *goin = goGetattr(p, "tmap:goin");
if (goin == NULL) {
Printv(f_go_wrappers, "\t", ivar, " := ", ln, NULL);
Printv(f_go_wrappers, "\t", ivar, " := ", NULL);
bool need_close = false;
if ((i == 0 && info->is_destructor) || ((i > 0 || !info->receiver || info->base || info->is_constructor) && goTypeIsInterface(p, pt))) {
Printv(f_go_wrappers, ".Swigcptr()", NULL);
Printv(f_go_wrappers, "getSwigcptr(", NULL);
need_close = true;
}
Printv(f_go_wrappers, ln, NULL);
if (need_close) {
Printv(f_go_wrappers, ")", NULL);
}
Printv(f_go_wrappers, "\n", NULL);
Setattr(p, "emit:goinput", ln);
@ -2506,7 +2512,7 @@ private:
Printv(interfaces, "\tSwigIs", go_base_name, "()\n", NULL);
Printv(f_go_wrappers, "func (p ", go_type_name, ") SwigGet", go_base_name, "() ", go_base_type, " {\n", NULL);
Printv(f_go_wrappers, "\treturn ", go_base_type_name, "(p.Swigcptr())\n", NULL);
Printv(f_go_wrappers, "\treturn ", go_base_type_name, "(getSwigcptr(p))\n", NULL);
Printv(f_go_wrappers, "}\n\n", NULL);
Printv(interfaces, "\tSwigGet", go_base_name, "() ", go_base_type, "\n", NULL);
@ -2708,7 +2714,7 @@ private:
Printv(f_go_wrappers, "}\n\n", NULL);
Printv(f_go_wrappers, "func (p *", director_struct_name, ") Swigcptr() uintptr {\n", NULL);
Printv(f_go_wrappers, "\treturn p.", go_type_name, ".Swigcptr()\n", NULL);
Printv(f_go_wrappers, "\treturn getSwigcptr(p.", go_type_name, ")\n", NULL);
Printv(f_go_wrappers, "}\n\n", NULL);
Printv(f_go_wrappers, "func (p *", director_struct_name, ") SwigIs", go_name, "() {\n", NULL);
@ -2866,9 +2872,15 @@ private:
String *goin = goGetattr(p, "tmap:goin");
if (goin == NULL) {
Printv(f_go_wrappers, "\t", ivar, " := ", ln, NULL);
Printv(f_go_wrappers, "\t", ivar, " := ", NULL);
bool need_close = false;
if (goTypeIsInterface(p, pt)) {
Printv(f_go_wrappers, ".Swigcptr()", NULL);
Printv(f_go_wrappers, "getSwigcptr(", NULL);
need_close = true;
}
Printv(f_go_wrappers, ln, NULL);
if (need_close) {
Printv(f_go_wrappers, ")", NULL);
}
Printv(f_go_wrappers, "\n", NULL);
} else {
@ -3461,9 +3473,15 @@ private:
// the goin typemap.
String *goin = goGetattr(p, "tmap:goin");
if (goin == NULL) {
Printv(f_go_wrappers, "\t", ivar, " := ", ln, NULL);
Printv(f_go_wrappers, "\t", ivar, " := ", NULL);
bool need_close = false;
if (goTypeIsInterface(p, pt)) {
Printv(f_go_wrappers, ".Swigcptr()", NULL);
Printv(f_go_wrappers, "getSwigcptr(", NULL);
need_close = true;
}
Printv(f_go_wrappers, ln, NULL);
if (need_close) {
Printv(f_go_wrappers, ")", NULL);
}
Printv(f_go_wrappers, "\n", NULL);
} else {
@ -3709,9 +3727,15 @@ private:
String *goin = goGetattr(p, "tmap:goin");
if (goin == NULL) {
Printv(f_go_wrappers, "\t", ivar, " := ", ln, NULL);
Printv(f_go_wrappers, "\t", ivar, " := ", NULL);
bool need_close = false;
if (goTypeIsInterface(p, pt)) {
Printv(f_go_wrappers, ".Swigcptr()", NULL);
Printv(f_go_wrappers, "getSwigcptr(", NULL);
need_close = true;
}
Printv(f_go_wrappers, ln, NULL);
if (need_close) {
Printv(f_go_wrappers, ")", NULL);
}
Printv(f_go_wrappers, "\n", NULL);
} else {
@ -3830,7 +3854,7 @@ private:
if (SwigType_type(result) != T_VOID) {
Printv(call, "swig_r = ", NULL);
if (result_is_interface) {
Printv(call, result_wrapper, "(", NULL);
Printv(call, result_wrapper, "(getSwigcptr(", NULL);
}
}
Printv(call, "swig_p.", go_with_over_name, "(", NULL);
@ -3890,7 +3914,7 @@ private:
Printv(call, ")", NULL);
if (result_is_interface) {
Printv(call, ".Swigcptr())", NULL);
Printv(call, "))", NULL);
}
Printv(call, "\n", NULL);