From 6b9905351219d914fd2aa218338fc44b028020e1 Mon Sep 17 00:00:00 2001
From: Bobby Holley <bobbyholley@gmail.com>
Date: Mon, 18 Mar 2013 20:39:53 -0700
Subject: [PATCH] Bug 850245 - Remove Off-Main-Thread XPCWrappedJS refcounting
 from DNSListenerProxy. r=mcmanus

---
 netwerk/dns/nsDNSService2.cpp | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/netwerk/dns/nsDNSService2.cpp b/netwerk/dns/nsDNSService2.cpp
index dd951481e0f..f85bafc8303 100644
--- a/netwerk/dns/nsDNSService2.cpp
+++ b/netwerk/dns/nsDNSService2.cpp
@@ -27,6 +27,7 @@
 #include "nsIOService.h"
 #include "nsCharSeparatedTokenizer.h"
 #include "nsNetAddr.h"
+#include "nsProxyRelease.h"
 
 #include "mozilla/Attributes.h"
 
@@ -516,23 +517,21 @@ class DNSListenerProxy MOZ_FINAL : public nsIDNSListener
 {
 public:
   DNSListenerProxy(nsIDNSListener* aListener, nsIEventTarget* aTargetThread)
-    : mListener(aListener)
+    // Sometimes aListener is a main-thread only object like XPCWrappedJS, and
+    // sometimes it's a threadsafe object like nsSOCKSSocketInfo. Use a main-
+    // thread pointer holder, but disable strict enforcement of thread invariants.
+    // The AddRef implementation of XPCWrappedJS will assert if we go wrong here.
+    : mListener(new nsMainThreadPtrHolder<nsIDNSListener>(aListener, false))
     , mTargetThread(aTargetThread)
   { }
 
-  ~DNSListenerProxy()
-  {
-    nsCOMPtr<nsIThread> mainThread(do_GetMainThread());
-    NS_ProxyRelease(mainThread, mListener);
-  }
-
   NS_DECL_ISUPPORTS
   NS_DECL_NSIDNSLISTENER
 
   class OnLookupCompleteRunnable : public nsRunnable
   {
   public:
-    OnLookupCompleteRunnable(nsIDNSListener* aListener,
+    OnLookupCompleteRunnable(nsMainThreadPtrHolder<nsIDNSListener>* aListener,
                              nsICancelable* aRequest,
                              nsIDNSRecord* aRecord,
                              nsresult aStatus)
@@ -542,23 +541,17 @@ public:
       , mStatus(aStatus)
     { }
 
-    ~OnLookupCompleteRunnable()
-    {
-      nsCOMPtr<nsIThread> mainThread(do_GetMainThread());
-      NS_ProxyRelease(mainThread, mListener);
-    }
-
     NS_DECL_NSIRUNNABLE
 
   private:
-    nsCOMPtr<nsIDNSListener> mListener;
+    nsMainThreadPtrHandle<nsIDNSListener> mListener;
     nsCOMPtr<nsICancelable> mRequest;
     nsCOMPtr<nsIDNSRecord> mRecord;
     nsresult mStatus;
   };
 
 private:
-  nsCOMPtr<nsIDNSListener> mListener;
+  nsMainThreadPtrHandle<nsIDNSListener> mListener;
   nsCOMPtr<nsIEventTarget> mTargetThread;
 };