Hello all, I'm trying to write a Cocoa application with embedded WebViews that navigates through a web application, eventually arriving at a page with a Java applet. I query some values from the Java applet via Javascript, and then at some point I close up and free the WebView.
The problem is that my program is quite unstable, and crashes at random points during the navigation process anywhere from the 2nd to 7th time I use it. I create an entirely new WebView for each attempt. I'll attach a typical backtrace below. Anyway, using basic troubleshooting techniques I believe I've narrowed the instability down to querying the Java applet through LiveConnect - testing the process with 100 iterations up to but NOT including the page with the applet was perfectly stable. 50 tests going to the page WITH the applet, but NOT querying it was also perfectly stable. As soon as I make even a basic query through LiveConnect though, I introduce instability. The crashes always seems to be cause in a Javascript Core Garbage Collection pass (see stack trace below), which leads me to thing that I'm doing something best avoided in my interactions - like, perhaps there's a dangling Javascript->Java proxy object where the Java peer was destroyed. But, basically, I'm looking for any insight anyone might have as to pitfalls that might not be obvious in this area. Problem occurs on 10.5.8 + All latest updates, and 10.6.5 + All latest updates. Java 6 on both platforms (required by the Applet) - using the Out-of-Process plugin on 10.5 and the in-process 32bit Java 6 on 10.6 Here is an example of my JS code, executed by [[webView windowScriptObject] evaluateWebScript:someJavaScript] on the main thread. The element in 'app' is a Java applet, getListenPort() is a Java method called via LiveConnect. I have two other scripts that are very similar, varying only in the method called. (function () { var app = document.getElementById(\"RemoteApplication\"); var ReturnMe = Number(app.getListenPort()); app = null; return ReturnMe; })() And here is a common sort of stack trace I'm getting (this one from 10.6) Thread 0 Crashed: Dispatch queue: com.apple.main-thread 0 com.apple.JavaScriptCore 0x9489f766 WTF::fastFree(void*) + 134 1 com.apple.WebCore 0x929be825 WebCore::CSSSelectorList::deleteSelectors() + 389 2 com.apple.WebCore 0x92a38269 WebCore::CSSStyleRule::~CSSStyleRule() + 57 3 com.apple.WebCore 0x929c3a04 WTF::Vector<WTF::RefPtr<WebCore::StyleBase>, 0ul>::shrink(unsigned long) + 84 4 com.apple.WebCore 0x92a38193 WebCore::StyleSheet::~StyleSheet() + 179 5 com.apple.WebCore 0x92a38066 WebCore::CSSStyleSheet::~CSSStyleSheet() + 102 6 com.apple.WebCore 0x92a91074 WTF::Vector<WTF::RefPtr<WebCore::StyleSheet>, 0ul>::shrink(unsigned long) + 84 7 com.apple.WebCore 0x92a29243 WebCore::StyleSheetList::~StyleSheetList() + 67 8 com.apple.WebCore 0x92a28cd9 WebCore::Document::~Document() + 3529 9 com.apple.WebCore 0x92a27f01 WebCore::HTMLDocument::~HTMLDocument() + 129 10 com.apple.WebCore 0x92a27def WebCore::Node::~Node() + 431 11 com.apple.WebCore 0x92c05a21 WebCore::HTMLIFrameElement::~HTMLIFrameElement() + 129 12 com.apple.WebCore 0x92b356fe WebCore::JSNode::~JSNode() + 382 13 com.apple.JavaScriptCore 0x9495a0d2 JSC::Heap::sweep() + 274 I find it odd that main isn't seen in the stack, but it never is. The crash nearly ALWAYS occurs in WTF::fastFree(), very occasionally occurring instead in some other memory management function. Any insight on where to look to further track this down would be greatly appreciated. -Chris Backas CONFIDENTIALITY NOTICE: This email (and any related attachments) contains information from InfoPlus (a service of Bristol Capital, Inc.). It is intended only for the addressee and may contain information that is confidential and/or otherwise exempt from disclosure under applicable law. If you are not the intended recipient or are acting as agent for the intended recipient, any use or disclosure of this communication is prohibited. If you have received this communication in error, please notify me immediately to arrange for the appropriate method of returning or disposing of the communication. If our respective Companies have confidentiality provisions in effect, this email and the materials contained herein are deemed CONFIDENTIAL and should be treated accordingly unless expressly provided otherwise.
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