Subj : Re: Spidermonkey: How to call a 'static method' from C
To   : netscape.public.mozilla.jseng
From : Peter Paulus
Date : Wed May 26 2004 01:27 pm

Sterling Bates wrote:
> Peter Paulus wrote:
> 
>> ok = JS_CallFunctionName(context, globalObj, "XYZHandler.onOpen",  0, 
>> NULL, &result);
> 
> 
> The obj parameter is the object containing the function, so you would 
> pass your XYZHandler JSObject in place of globalObj here, then simply 
> call "onOpen".
> 
> Sterling

Thank you for the prompt response.

I could not find a operation in the API that resolves a name like 
'XYZHandler.onOpen' to the XYZHandler object. So I've come up with the 
code below:

void* Context::callFunction(const char* name, unsigned int argc, long 
argv[])
{
jsval result = 0L;

JSScript* script = scripts.top();
JSBool ok = JS_ExecuteScript(context, globalObj, script, &result);
if (not ok)
    {
    ...
    }

result=0L;
JSObject* targetObject = 0L;
char targetName[256];
ok = resolveScope(name, globalObj, &targetObject,  (char*) targetName);

if (not ok)
   {
   ...
   }

ok = JS_CallFunctionName(context, targetObject, targetName,  argc, 
argv,  &result);
if (not ok)
   {
   ...
   }
return((void*) result);
}

JSBool Context::resolveScope(const char* qualifiedName, JSObject* 
startObject, JSObject** targetObject, char* targetName)
{
JSBool ok = true;
jsval result = JSVAL_VOID;
JSObject* currentObject = startObject;

*targetObject = JSVAL_NULL;
*targetName = '\0';

char namePart[256] = { '\0' };
unsigned short nameIndex = 0;
unsigned short partIndex = 0;
char c;
while(c = qualifiedName[nameIndex], c and ok)
    {
    switch(c)
       {
       case '.': // all but last namepart found
          {
          // zero-terminate namepart
	 namePart[partIndex] = '\0';
          // get property
          ok = JS_GetProperty(context, currentObject,  (char*) namePart, 
&result);
          if (JSVAL_IS_OBJECT(result))
            {
            currentObject = JSVAL_TO_OBJECT(result);
            }
          else
            {
            ok = false;
            }
          // reset the namepart
          partIndex = 0;
          namePart[0] = '\0';
          break;
          }
       default: // build the namepart
          {
          namePart[partIndex++] = c;
          }
       }
    nameIndex++;
    }

if (ok)
   {
   // zero-terminate namepart
   namePart[partIndex] = '\0';

   ok = JS_GetProperty(context, currentObject, namePart, &result);
   if (ok)
     {
     *targetObject = currentObject;
     strcpy(targetName, namePart);
     }
   }

return(ok);
}

This now works fine for me.

With kind regards,
Peter Paulus

.