523651 - Add a CallQueryInterface that can work with nsCOMPtr

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Boris Zbarsky [:bzbarsky]]

I'm tired of all the casting if I want to QI something with ambiguous nsISupports inheritance.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Fix

Comment 2

[Benjamin Smedberg]

Comment on attachment 407554 [details] [diff] [review]
Fix

The static_cast *looks* wrong... I thought static_cast wasn't supposed to run cast operators, which is obviously what's happening here. I'd be happier with a c-style cast here: (DestinationType**) aDestination

Comment 3

[Boris Zbarsky [:bzbarsky]]

static_cast does do cast operators.  Testcase:

#include "stdio.h"
class A {
public:
  operator int() { return 5; }
};
int main() {
  A a;
  printf("%d\n", static_cast<int>(a));
}

prints 5 over here.  I can switch to c-style, though.

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I think static_cast is better; less risk of accidentally turning into a reinterpret_cast.

Comment 5

[Boris Zbarsky [:bzbarsky]]

Pushed http://hg.mozilla.org/mozilla-central/rev/a75d7681fa2f