android specific Spidermonkey NoGCScope crash

cocos2d-x JavaScript
#1

Hi,

I’ve run into a crash that I don’t really understand, and am hoping for help sorting out. I suspect that this may be some form of threading problem, but I’m not sure. Any help or angles of investigation will be appreciated!

The setup:

I’m trying to complete facebook login. I’ve got it working correctly in Java, but when I try to pass the string back up to JS I get a crash with the below stack:

#00  pc 001ca13a  /data/data/com.redhotlabs.bingo/lib/libgame.so (JS::InNoGCScope()+17)
#01  pc 002ef919  /data/data/com.redhotlabs.bingo/lib/libgame.so
#02  pc 001d27af  /data/data/com.redhotlabs.bingo/lib/libgame.so (JS_NewStringCopyZ+62)
#03  pc 00151449  /data/data/com.redhotlabs.bingo/lib/libgame.so (JSStringCallback::callbackFunc(char const*)+64)
#04  pc 00142fb7  /data/data/com.redhotlabs.bingo/lib/libgame.so (Java_com_redhotlabs_bingo_FacebookManager_currentFacebookUserChanged+46)
#05  pc 0001f3b0  /system/lib/libdvm.so (dvmPlatformInvoke+112)
#06  pc 0004eb6f  /system/lib/libdvm.so (dvmCallJNIMethod(unsigned int const*, JValue*, Method const*, Thread*)+394)
#07  pc 00050c8b  /system/lib/libdvm.so (dvmResolveNativeMethod(unsigned int const*, JValue*, Method const*, Thread*)+174)
#08  pc 000288a4  /system/lib/libdvm.so

the Java code (all of this seems to work fine, and the json encoded string being passed to c*+ is correct:
<pre>
public native void currentFacebookUserChanged;
/* Displays the facebook login dialog./
public void showLoginDialog {
// start Facebook Login
Session.openActiveSession;
}
private class SessionStatusCallback implements Session.StatusCallback {
Override public void call(Session session, SessionState state, Exception exception) { if (session.isOpened()) { // make request to the /me API Request.executeMeRequestAsync(session, new Request.GraphUserCallback() { // callback after Graph API response with user objectOverride
public void onCompleted {
if {
String data = user.getInnerJSONObject.toString;
FacebookManager.getInstance.currentFacebookUserChanged;
}
}
}
}
}
}
</pre>
my c*+ code:

//JSStringCallback extends JSCallbackWrapper, and is retained when passed down to the c++ code
static JSStringCallback* s_userChangedListener;

extern "C"
{
    void Java__FacebookManager_currentFacebookUserChanged(JNIEnv* env, jobject thiz, jstring data) {
        if(s_userChangedListener) {
            const char* nativeData = (env)->GetStringUTFChars( data, 0);
            s_userChangedListener->callbackFunc(nativeData);
        }
    }
}

the JSStringCallback’s callFunc code:

void JSStringCallback::callbackFunc(const char* arg) {

    JSObject* thisObj = JSVAL_IS_VOID(jsThisObj) ? NULL : JSVAL_TO_OBJECT(jsThisObj);
    JSContext *cx = ScriptingCore::getInstance()->getGlobalContext();

    jsval retval;
    if(jsCallback != JSVAL_VOID) {
        CCLog(arg); //This properly prints out the json string of the FB user data
        JSString *str = JS_NewStringCopyZ(cx, arg); //This line throws the error
        jsval senderVal = STRING_TO_JSVAL(str);
        JS_AddValueRoot(cx, &senderVal);
        JS_CallFunctionValue(cx, thisObj, jsCallback, 1, &senderVal, &retval);
        JS_RemoveValueRoot(cx, &senderVal);

//        JS_CallFunctionValue(cx, thisObj, jsCallback, 0, NULL, &retval); //This line will also throw the error if the above lines are commented out

    }
}

I’ve tried putting the c++ call into the UI thread in java using an Async task, but that doesn’t seem to have changed anything.

Thanks for any help you can give,
Mark Henderson

#2

Plz make sure that JSStringCallback::callbackFunc is in GL thread since cocos2d-x is in GL thread.

#3

James Chen wrote:

Plz make sure that JSStringCallback::callbackFunc is in GL thread since cocos2d-x is in GL thread.

I ran into the same case as well, could you please give some tips on how to interact cocos2d-x in another thread?

#4

James Chen wrote:

Plz make sure that JSStringCallback::callbackFunc is in GL thread since cocos2d-x is in GL thread.

This was the problem:)
I changed my JSStringCallback function to work as below, and it seems to have solved my issue:
<pre>
void JSStringCallback::callbackFunc {
this>m_arg = arg;
CCDirector::sharedDirector()->getScheduler()>scheduleSelector, this, 0, false);
}
void JSStringCallback::scheduledCallback {
const char * arg = this>m_arg;
JSObject* thisObj = JSVAL_IS_VOID(jsThisObj) ? NULL : JSVAL_TO_OBJECT(jsThisObj);
JSContext cx = ScriptingCore::getInstance->getGlobalContext;
jsval retval;
if {
CCLog;
// JSStringstr1 = JS_NewStringCopyZ(cx, “test”);
CCLog(arg);
JSString *str = JS_NewStringCopyZ(cx, arg);
jsval senderVal = STRING_TO_JSVAL(str);
JS_AddValueRoot(cx, &senderVal);
JS_CallFunctionValue(cx, thisObj, jsCallback, 1, &senderVal, &retval);
JS_CallFunctionValue(cx, thisObj, jsCallback, 0, NULL, &retval);
JS_RemoveValueRoot(cx, &senderVal);

}
}