This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Etsi tuesta

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Lue lisää

Ketju on arkistoitu. Esitä kysymys, jos tarvitset apua.

why JS_AddValueRoot() leads to "losing efficacy" of GC

  • 2 vastausta
  • 1 henkilöllä on sama ongelma
  • 11 näyttöä
  • Viimeisin kirjoittaja blueconch.hg

blueconch.hg
blueconch.hg
more options

Here's my js code: 

     window.onload = function () {
       ...
       CarObject.addCallback("StringEvent", function(arg1, arg2){
         alert(arg2);
       });
       ...
     }

CarObject is a js variable, it maps to a C++ object internally, here I add a callback to the CarObject. as you see, the callback function is not a global function, so the callback function will be freed by GC. We use JS_AddValueRoot() which will add the callback function to GC's root set, this means the callback function(JSFunction *) will be protected from GC. but I found that it caught GC won't work, many object will be leaked when firefox exit.

Here's my js code: window.onload = function () { ... CarObject.addCallback("StringEvent", function(arg1, arg2){ alert(arg2); }); ... } CarObject is a js variable, it maps to a C++ object internally, here I add a callback to the CarObject. as you see, the callback function is not a global function, so the callback function will be freed by GC. We use JS_AddValueRoot() which will add the callback function to GC's root set, this means the callback function(JSFunction *) will be protected from GC. but I found that it caught GC won't work, many object will be leaked when firefox exit.

Kaikki vastaukset (2)

philipp
philipp
  • Moderator
more options

hello blueconch.hg, could you file a bug report for that issue at bugzilla.mozilla.org there it will get the attention of developers quicker! thank you...

blueconch.hg
blueconch.hg Kysymyksen kysyjä
more options

thanks philipp, I'm using source code of fennec21.0, I'm not sure whether it will occur on the lasted version. The problem(GC losing effective, there will be many leads when fennec exit.) may not be caught by JS_AddValueRoot(), maybe it's our code's problem. But I will try your suggestion, put it to https://bugzilla.mozilla.org/