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Improve director unwrap detection for the return type 

Resolve the return type to correctly determine if the type is a pointer or
reference to a director class.

SwigType_refptr_count_return() recently added as a simpler fix is no
longer needed.

The conventional approach of using the "type" rather than "decl" to
analyse the return type is used instead too.

Issue #1823
This commit is contained in:
William S Fulton 2022-10-10 08:27:44 +01:00
parent 4a397869a2
commit 2f55379687
10 changed files with 76 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
CHANGES.current
View File

@ -7,6 +7,13 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
Version 4.1.0 (in progress)
===========================
2022-10-10: treitmayr, wsfulton
[Python, Ruby] #1811 #1823 Fix invalid code generated in some cases when
returning a pointer or reference to a director-enabled class instance.
This previously only worked in very simple cases, now return types are
resolved to fix. A bug in template instantations using pointers also
works now.
2022-10-06: wsfulton
[CFFI] #1966 #2200 Remove code for Common Lisp CFFI. We dropped support
for it in SWIG 4.0.0 by disabling it as the first stage. This is the

11
Examples/test-suite/director_unwrap_result.i
View File

@ -25,6 +25,8 @@ class Element {
return &selfptr;
}
};
typedef Element * element_ptr_t;
typedef Element & element_ref_t;
class Storage {
public:
@ -45,6 +47,15 @@ class Storage {
Element *&getElementPtrRef() {
return *getIt();
}
element_ref_t getElementRefTypedef() {
return **getIt();
}
element_ptr_t getElementPtrTypedef() {
return *getIt();
}
element_ptr_t &getElementPtrRefTypedef() {
return *getIt();
}
};
template<class T> class StorageTmpl {

14
Examples/test-suite/ruby/director_unwrap_result_runme.rb
View File

@ -41,12 +41,26 @@ swig_assert_equal('s.getElementPtr', 'e', binding)
swig_assert_equal('s.getElementRef.class', 'MyElement', binding)
swig_assert_equal('s.getElementRef', 'e', binding)
# this shows that the director class was unwrapped:
swig_assert_equal('s.getElementPtrTypedef.class', 'MyElement', binding)
swig_assert_equal('s.getElementPtrTypedef', 'e', binding)
# this shows that the director class was unwrapped:
swig_assert_equal('s.getElementRefTypedef.class', 'MyElement', binding)
swig_assert_equal('s.getElementRefTypedef', 'e', binding)
# this is not unwrapped:
swig_assert_equal('s.getElementPtrPtr.class', 'SWIG::TYPE_p_p_Element', binding)
swig_assert_equal('s.getElementPtrPtr.class', 'SWIG::TYPE_p_p_Element', binding)
# this is not unwrapped:
swig_assert_equal('s.getElementPtrRef.class', 'SWIG::TYPE_p_p_Element', binding)
swig_assert_equal('s.getElementPtrRef.class', 'SWIG::TYPE_p_p_Element', binding)
# this is not unwrapped:
swig_assert_equal('s.getElementPtrRefTypedef.class', 'SWIG::TYPE_p_p_Element', binding)
swig_assert_equal('s.getElementPtrRefTypedef.class', 'SWIG::TYPE_p_p_Element', binding)
############################
# test with a template class

6
Source/CParse/templ.c
View File

@ -248,7 +248,7 @@ static void cparse_template_expand(Node *templnode, Node *n, String *tname, Stri
static void cparse_fix_function_decl(String *name, SwigType *decl, SwigType *type) {
String *prefix;
int prefixLen;
SwigType* last;
SwigType *last;
/* The type's prefix is what potentially has to be moved to the end of 'decl' */
prefix = SwigType_prefix(type);
@ -275,8 +275,7 @@ static void cparse_fix_function_decl(String *name, SwigType *decl, SwigType *typ
Append(decl, prefix);
Delslice(type, 0, prefixLen);
if (template_debug) {
Printf(stdout, " change function '%s' to type='%s', decl='%s'\n",
name, type, decl);
Printf(stdout, " change function '%s' to type='%s', decl='%s'\n", name, type, decl);
}
}
@ -510,7 +509,6 @@ int Swig_cparse_template_expand(Node *n, String *rname, ParmList *tparms, Symtab
}
}
}
cparse_postprocess_expanded_template(n);
/* Patch bases */

35
Source/Modules/directors.cxx
View File

@ -233,3 +233,38 @@ void Swig_director_parms_fixup(ParmList *parms) {
}
}
/* -----------------------------------------------------------------------------
* Swig_director_can_unwrap()
*
* Determine whether a function's return type can be returned as an existing
* target language object instead of creating a new target language object.
* Must be a director class and only for return by pointer or reference only
* (not by value or by pointer to pointer etc).
* ----------------------------------------------------------------------------- */
bool Swig_director_can_unwrap(Node *n) {
// FIXME: this will not try to unwrap directors returned as non-director
// base class pointers!
bool unwrap = false;
String *type = Getattr(n, "type");
SwigType *t = SwigType_typedef_resolve_all(type);
SwigType *t1 = SwigType_strip_qualifiers(t);
SwigType *prefix = SwigType_prefix(t1);
if (Strcmp(prefix, "p.") == 0 || Strcmp(prefix, "r.") == 0) {
Node *parent = Swig_methodclass(n);
Node *module = Getattr(parent, "module");
Node *target = Swig_directormap(module, t1);
if (target)
unwrap = true;
}
Delete(prefix);
Delete(t1);
Delete(t);
return unwrap;
}

24
Source/Modules/python.cxx
View File

@ -3150,25 +3150,9 @@ public:
Replaceall(tm, "$owner", "0");
}
}
// FIXME: this will not try to unwrap directors returned as non-director
// base class pointers!
/* New addition to unwrap director return values so that the original
* python object is returned instead.
*/
#if 1
int unwrap = 0;
String *decl = Getattr(n, "decl");
if (SwigType_refptr_count_return(decl) == 1) {
String *type = Getattr(n, "type");
//Node *classNode = Swig_methodclass(n);
//Node *module = Getattr(classNode, "module");
Node *module = Getattr(parent, "module");
Node *target = Swig_directormap(module, type);
if (target)
unwrap = 1;
}
if (unwrap) {
// Unwrap return values that are director classes so that the original Python object is returned instead.
if (!constructor && Swig_director_can_unwrap(n)) {
Wrapper_add_local(f, "director", "Swig::Director *director = 0");
Printf(f->code, "director = SWIG_DIRECTOR_CAST(%s);\n", Swig_cresult_name());
Append(f->code, "if (director) {\n");
@ -3180,9 +3164,7 @@ public:
} else {
Printf(f->code, "%s\n", tm);
}
#else
Printf(f->code, "%s\n", tm);
#endif
Delete(tm);
} else {
Swig_warning(WARN_TYPEMAP_OUT_UNDEF, input_file, line_number, "Unable to use return type %s in function %s.\n", SwigType_str(d, 0), name);

24
Source/Modules/ruby.cxx
View File

@ -1871,24 +1871,8 @@ public:
else
Replaceall(tm, "$owner", "0");
#if 1
// FIXME: this will not try to unwrap directors returned as non-director
// base class pointers!
/* New addition to unwrap director return values so that the original
* Ruby object is returned instead.
*/
bool unwrap = false;
String *decl = Getattr(n, "decl");
if (SwigType_refptr_count_return(decl) == 1) {
String *type = Getattr(n, "type");
Node *parent = Swig_methodclass(n);
Node *modname = Getattr(parent, "module");
Node *target = Swig_directormap(modname, type);
if (target)
unwrap = true;
}
if (unwrap) {
// Unwrap return values that are director classes so that the original Ruby object is returned instead.
if (Swig_director_can_unwrap(n)) {
Wrapper_add_local(f, "director", "Swig::Director *director = 0");
Printf(f->code, "director = dynamic_cast<Swig::Director *>(%s);\n", Swig_cresult_name());
Printf(f->code, "if (director) {\n");
@ -1900,9 +1884,7 @@ public:
} else {
Printf(f->code, "%s\n", tm);
}
#else
Printf(f->code, "%s\n", tm);
#endif
Delete(tm);
} else {
Swig_warning(WARN_TYPEMAP_OUT_UNDEF, input_file, line_number, "Unable to use return type %s.\n", SwigType_str(t, 0));

1
Source/Modules/swigmod.h
View File

@ -405,6 +405,7 @@ String *Swig_method_decl(SwigType *return_base_type, SwigType *decl, const_Strin
String *Swig_director_declaration(Node *n);
void Swig_director_emit_dynamic_cast(Node *n, Wrapper *f);
void Swig_director_parms_fixup(ParmList *parms);
bool Swig_director_can_unwrap(Node *n);
/* directors.cxx end */
/* Utilities */

1
Source/Swig/swig.h
View File

@ -140,7 +140,6 @@ extern "C" {
extern String *SwigType_pop(SwigType *t);
extern void SwigType_push(SwigType *t, String *s);
extern SwigType *SwigType_last(SwigType *t);
extern int SwigType_refptr_count_return(const SwigType *t);
extern List *SwigType_parmlist(const SwigType *p);
extern String *SwigType_parm(const SwigType *p);
extern String *SwigType_str(const SwigType *s, const_String_or_char_ptr id);

43
Source/Swig/typeobj.c
View File

@ -249,49 +249,6 @@ SwigType *SwigType_last(SwigType *t) {
return result;
}
/* -----------------------------------------------------------------------------
* SwigType_refptr_count_return()
*
* Returns the number of pointer and reference indirections found in the given
* type. For functions this concerns the return type.
* For example:
* r.p. => 2
* q(const).p. => 1
* r.f(int).p.p. => 2
* f().p.q(const).p. => 2
* ----------------------------------------------------------------------------- */
int SwigType_refptr_count_return(const SwigType *t) {
char *c;
char *last;
int sz;
int result = 0;
if (!t)
return 0;
c = Char(t);
last = c;
while (*c) {
last = c;
sz = element_size(c);
c = c + sz;
if (*(c-1) == '.') {
if (((last[0] == 'p') || (last[0] == 'r')) && (last[1] == '.')) {
result++;
} else if (strncmp(last, "f(", 2) == 0) {
/* restart counter if this is a function type */
result = 0;
}
}
if (*c == '.') {
c++;
}
}
return result;
}
/* -----------------------------------------------------------------------------
* SwigType_parm()
*