[cmake,tinyPy] Rely on caller to catch None as return value for Pytho…

…n functions which return a string

This allows user to cancel file dialog opened by a project script without
getting slapped in the face with a tinyPy exception.

avidemux_plugins/ADM_scriptEngines/tinyPy/src/GUI_gen.cpp

@@ -11,7 +11,7 @@ static tp_obj zzpy_fileWriteSelect(TP)
   IEditor *p0 = editor;
   const char *p1 = pm.asString();
   char *r =   pyFileSelWrite(p0,p1); 
-  if(!r) pm.raise("pyGui : null pointer");
+  if(!r) return tp_None;
 
   tp_obj o = tp_string_copy(tp, r, strlen(r));
   ADM_dealloc(r);
@@ -44,7 +44,7 @@ static tp_obj zzpy_dirSelect(TP)
   IEditor *p0 = editor;
   const char *p1 = pm.asString();
   char *r =   pyDirSelect(p0,p1); 
-  if(!r) pm.raise("pyGui : null pointer");
+  if(!r) return tp_None;
 
   tp_obj o = tp_string_copy(tp, r, strlen(r));
   ADM_dealloc(r);
@@ -77,7 +77,7 @@ static tp_obj zzpy_fileReadSelect(TP)
   IEditor *p0 = editor;
   const char *p1 = pm.asString();
   char *r =   pyFileSelRead(p0,p1); 
-  if(!r) pm.raise("pyGui : null pointer");
+  if(!r) return tp_None;
 
   tp_obj o = tp_string_copy(tp, r, strlen(r));
   ADM_dealloc(r);

avidemux_plugins/ADM_scriptEngines/tinyPy/src/adm_gen.cpp

@@ -293,7 +293,7 @@ static tp_obj zzpy_getVideoCodec(TP)
   void *me = (void *)pm.asThis(&self, ADM_PYID_AVIDEMUX);
 
   char *r =   editor->getVideoCodec(); 
-  if(!r) pm.raise("pyAdm : null pointer");
+  if(!r) return tp_None;
 
   tp_obj o = tp_string_copy(tp, r, strlen(r));
   ADM_dealloc(r);

cmake/admPyClass.pl

@@ -212,7 +212,7 @@ sub genReturn
         }
          if($retType=~m/str/)
         {
-                return "  if(!r) pm.raise(\"$className : null pointer\");\n
+                return "  if(!r) return tp_None;\n
   tp_obj o = tp_string_copy(tp, r, strlen(r));
   ADM_dealloc(r);
   return o;";