Bugfix #1542466 added code to allow mapping Lua nil's <-> C/C++ NULL's

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@9256 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -1,6 +1,12 @@
 Version 1.3.30 (in progress)
 ============================
 
+08/21/2006: mgossage
+            [Lua]
+	    Bugfix #1542466 added code to allow mapping Lua nil's <-> C/C++ NULL's
+	    updated various typemaps to work correctly with the changes
+	    added voidtest_runme.lua to show the features working
+
 08/19/2006: wuzzeb (John Lenz)
 	    [Guile] Add feature:constasvar to export constants as variables instead of functions
             that return the constant value.
@@ -19,6 +25,7 @@ Version 1.3.30 (in progress)
 	    -nocwrap mode.
 
 07/21/2006: mgossage
+            [Lua]
 	    Bugfix #1526022 pdated std::string to support strings with '\0' inside them
 	    updated typemaps.i to add support for pointer to pointers
 

Examples/test-suite/lua/voidtest_runme.lua

@@ -0,0 +1,37 @@
+-- demo of lua swig
+require("import")	-- the import fn
+import("voidtest")	-- import lib
+
+-- test calling functions
+voidtest.globalfunc()
+f = voidtest.Foo()
+f:memberfunc()  -- member fns must have : not a .
+
+voidtest.Foo_staticmemberfunc() -- static member fns are still a little messy
+
+v1 = voidtest.vfunc1(f)
+v2 = voidtest.vfunc2(f)
+
+assert(swig_equals(v1,v2)) -- a raw equals will not work, we look at the raw pointers
+
+v3 = voidtest.vfunc3(v1)
+assert(swig_equals(v3,f))
+
+v4 = voidtest.vfunc1(f)
+assert(swig_equals(v4,v1))
+
+v3:memberfunc()
+
+-- also testing nil's support
+-- nil, are acceptable anywhere a pointer is
+n1 = voidtest.vfunc1(nil)
+n2 = voidtest.vfunc2(nil)
+
+assert(n1==nil)
+assert(n2==nil)
+
+n3 = voidtest.vfunc3(n1)
+n4 = voidtest.vfunc1(nil)
+
+assert(n3==nil)
+assert(n4==nil)

Lib/lua/lua.swg

@@ -96,7 +96,15 @@
 %{  lua_pushfstring(L,"%c",*$1); SWIG_arg++;%}
 
 // pointers and references
-%typemap(in,checkfn="lua_isuserdata") SWIGTYPE*,SWIGTYPE&,SWIGTYPE[]
+// under SWIG rules, it is ok, to have a pass in a lua nil, 
+// it should be converted to a SWIG NULL.
+// This will only be allowed for pointers & arrays, not refs or by value
+// the checkfn lua_isuserdata will only work for userdata
+// the checkfn SWIG_isptrtype will work for both userdata and nil's
+%typemap(in,checkfn="SWIG_isptrtype") SWIGTYPE*,SWIGTYPE[]
+%{$1=($1_ltype)SWIG_MustGetPtr(L,$input,$descriptor,0,$argnum,"$symname");%}
+
+%typemap(in,checkfn="lua_isuserdata") SWIGTYPE&
 %{$1=($1_ltype)SWIG_MustGetPtr(L,$input,$descriptor,0,$argnum,"$symname");%}
 
 %typemap(out) SWIGTYPE*,SWIGTYPE&
@@ -138,9 +146,13 @@
 A function void fn(void*) should take any kind of pointer as a parameter (just like C/C++ does)
 but if its an output, then it should be wrappered like any other SWIG object (using default typemap)
 */
-%typemap(in,checkfn="lua_isuserdata") void*
-%{$1=((swig_lua_userdata*)(lua_touserdata(L,$input)))->ptr;%}
+//%typemap(in,checkfn="lua_isuserdata") void*
+//%typemap(in,checkfn="SWIG_isptrtype") void*
+//%{$1=((swig_lua_userdata*)(lua_touserdata(L,$input)))->ptr;%}
 
+%typemap(in,checkfn="SWIG_isptrtype") void*
+%{$1=($1_ltype)SWIG_MustGetPtr(L,$input,0,0,$argnum,"$symname");%}
+//%{SWIG_ConvertPtr(L,$input, (void **) &ptr, 0, 0)); %}
 
 /* -----------------------------------------------------------------------------
  *                          constants typemaps
@@ -206,7 +218,16 @@ parmeters match which function
   $1 = lua_isstring(L,$input);
 }
 
-%typecheck(SWIG_TYPECHECK_POINTER) SWIGTYPE, SWIGTYPE *, SWIGTYPE &, SWIGTYPE [] {
+%typecheck(SWIG_TYPECHECK_POINTER) SWIGTYPE *, SWIGTYPE [] {
+  void *ptr;
+  if (SWIG_isptrtype(L,$input)==0 || SWIG_ConvertPtr(L,$input, (void **) &ptr, $1_descriptor, 0)) {
+    $1 = 0;
+  } else {
+    $1 = 1;
+  }
+}
+
+%typecheck(SWIG_TYPECHECK_POINTER) SWIGTYPE, SWIGTYPE & {
   void *ptr;
   if (lua_isuserdata(L,$input)==0 || SWIG_ConvertPtr(L,$input, (void **) &ptr, $1_descriptor, 0)) {
     $1 = 0;
@@ -217,7 +238,7 @@ parmeters match which function
 
 %typecheck(SWIG_TYPECHECK_VOIDPTR) void * {
   void *ptr;
-  if (lua_isuserdata(L,$input)==0 || SWIG_ConvertPtr(L,$input, (void **) &ptr, 0, 0)) {
+  if (SWIG_isptrtype(L,$input)==0 || SWIG_ConvertPtr(L,$input, (void **) &ptr, 0, 0)) {
     $1 = 0;
   } else {
     $1 = 1;

Lib/lua/luarun.swg

@@ -109,6 +109,9 @@ typedef struct {
 			lua_pushcfunction(L, f), \
 			lua_rawset(L,-3))
 
+/* special helper for allowing 'nil' for usertypes */
+#define SWIG_isptrtype(L,I) (lua_isuserdata(L,I) || lua_isnil(L,I))
+
 /* -----------------------------------------------------------------------------
  * global variable support code: modules
  * ----------------------------------------------------------------------------- */
@@ -507,10 +510,16 @@ SWIGRUNTIME int  SWIG_Lua_ConvertPtr(lua_State* L,int index,void** ptr,swig_type
 {
 	swig_lua_userdata* usr;
 	swig_cast_info *cast;
+	if (lua_isnil(L,index)){*ptr=0; return 0;}    /* special case: lua nil => NULL pointer */
 	usr=(swig_lua_userdata*)lua_touserdata(L,index);	/* get data */
 	if (usr)
 	{
-		cast=SWIG_TypeCheckStruct(usr->type,type);
+                if (!type)                           /* special cast void*, no casting fn */
+                {
+                    *ptr=usr->ptr;
+                    return 0; /* ok */
+                }
+		cast=SWIG_TypeCheckStruct(usr->type,type); /* performs normal type checking */
 		if (cast)
 		{
 			*ptr=SWIG_TypeCast(cast,usr->ptr);
@@ -553,8 +562,9 @@ SWIGRUNTIME int SWIG_Lua_equal(lua_State* L)
 		return 0;	/* nil reply */
 	usr1=(swig_lua_userdata*)lua_touserdata(L,1);	/* get data */
 	usr2=(swig_lua_userdata*)lua_touserdata(L,2);	/* get data */
-	result=(usr1->ptr==usr2->ptr && usr1->type==usr2->type);
-	lua_pushboolean(L,result);
+	/*result=(usr1->ptr==usr2->ptr && usr1->type==usr2->type); only works if type is the same*/
+	result=(usr1->ptr==usr2->ptr);
+        lua_pushboolean(L,result);
 	return 1;
 }