User:GijsKruitbosch/JS Debugging/DocumentFromException

From MozillaWiki
Jump to: navigation, search

Main aim

Be able to determine the document an error came off from within chrome js/extension/etc.

We'll use plan A unless we run out of time to do this on branch, in which case we have plan B for backup..

Plan A

  • Make nsIConsoleMessage implement nsIException (rather, make nsConsoleMessage also implement nsIException if it is from an uncaught exception; the QI should fail if it's a message that isn't from an exception, ideally --shaver)
  • Make nsIException have useful stuff in its data field that can be used to determine the document that the message came off. Note: what? (as in, exactly) (How about an nsIDocument? Should check with bz and the docshell mafia here. --shaver)

Plan B


Rob showed me an easier, all JS way:

The starting point is the jsdIStackFrame "frame" parameter in function jsdExecutionHook, from which we obtain the globalObject of its executionContext.

We then continue chasing references from globalObject and finally get to a window thanks to getBaseWindowFromWindow.