Bug 478304 - 'Let nsRunnableMethod be used with non-void-returning functions'. r=bsmedberg.

content/base/src/nsXMLHttpRequest.cpp

@@ -500,30 +500,6 @@ nsACProxyListener::GetInterface(const nsIID & aIID, void **aResult)
   return QueryInterface(aIID, aResult);
 }
 
-/**
- * Simple class to resume timeouts on a window asynchronously.
- */
-class nsResumeTimeoutsRunnable : public nsIRunnable
-{
-public:
-  NS_DECL_ISUPPORTS
-
-  nsResumeTimeoutsRunnable(nsPIDOMWindow* aWindow)
-  : mWindow(aWindow)
-  {
-    NS_ASSERTION(aWindow, "Null pointer!");
-  }
-
-  NS_IMETHOD Run() {
-    return mWindow->ResumeTimeouts();
-  }
-
-private:
-  nsCOMPtr<nsPIDOMWindow> mWindow;
-};
-
-NS_IMPL_THREADSAFE_ISUPPORTS1(nsResumeTimeoutsRunnable, nsIRunnable)
-
 /**
  * Gets the nsIDocument given the script context. Will return nsnull on failure.
  *
@@ -2813,7 +2789,9 @@ nsXMLHttpRequest::Send(nsIVariant *aBody)
         nsCOMPtr<nsPIDOMWindow> suspendedWindow(do_QueryInterface(topWindow));
         if (suspendedWindow) {
           suspendedWindow->SuspendTimeouts();
-          resumeTimeoutRunnable = new nsResumeTimeoutsRunnable(suspendedWindow);
+          resumeTimeoutRunnable = NS_NEW_RUNNABLE_METHOD(nsPIDOMWindow,
+                                                         suspendedWindow.get(),
+                                                         ResumeTimeouts);
         }
       }
     }

content/xbl/src/nsBindingManager.h

@@ -48,6 +48,7 @@
 #include "nsCycleCollectionParticipant.h"
 #include "nsXBLBinding.h"
 #include "nsTArray.h"
+#include "nsThreadUtils.h"
 
 class nsIContent;
 class nsIXPConnectWrappedJS;
@@ -61,7 +62,6 @@ class nsStyleSet;
 class nsXBLBinding;
 template<class E> class nsRefPtr;
 typedef nsTArray<nsRefPtr<nsXBLBinding> > nsBindingList;
-template<class T> class nsRunnableMethod;
 class nsIPrincipal;
 
 class nsBindingManager : public nsStubMutationObserver

layout/base/nsPresContext.h

@@ -68,6 +68,7 @@
 #include "nsRegion.h"
 #include "nsTArray.h"
 #include "nsAutoPtr.h"
+#include "nsThreadUtils.h"
 
 class nsImageLoader;
 #ifdef IBMBIDI
@@ -92,7 +93,6 @@ class nsILookAndFeel;
 class nsICSSPseudoComparator;
 class nsIAtom;
 struct nsStyleBackground;
-template <class T> class nsRunnableMethod;
 class nsIRunnable;
 class gfxUserFontSet;
 class nsUserFontSet;

xpcom/glue/nsThreadUtils.h

@@ -247,13 +247,13 @@ protected:
 // An event that can be used to call a method on a class.  The class type must
 // support reference counting. This event supports Revoke for use
 // with nsRevocableEventPtr.
-template <class T>
+template <class ClassType, typename ReturnType = void>
 class nsRunnableMethod : public nsRunnable
 {
 public:
-  typedef void (T::*Method)();
+  typedef ReturnType (ClassType::*Method)();
 
-  nsRunnableMethod(T *obj, Method method)
+  nsRunnableMethod(ClassType *obj, Method method)
     : mObj(obj), mMethod(method) {
     NS_ADDREF(mObj);
   }
@@ -264,18 +264,38 @@ public:
     (mObj->*mMethod)();
     return NS_OK;
   }
-  
+
   void Revoke() {
     NS_IF_RELEASE(mObj);
   }
 
-private:
+  // These ReturnTypeEnforcer classes set up a blacklist for return types that
+  // we know are not safe. The default ReturnTypeEnforcer compiles just fine but
+  // already_AddRefed will not.
+  template <typename OtherReturnType>
+  class ReturnTypeEnforcer
+  {
+  public:
+    typedef int ReturnTypeIsSafe;
+  };
+
+  template <class T>
+  class ReturnTypeEnforcer<already_AddRefed<T> >
+  {
+    // No ReturnTypeIsSafe makes this illegal!
+  };
+
+  // Make sure this return type is safe.
+  typedef typename ReturnTypeEnforcer<ReturnType>::ReturnTypeIsSafe check;
+
+protected:
   virtual ~nsRunnableMethod() {
     NS_IF_RELEASE(mObj);
   }
 
-  T      *mObj;
-  Method  mMethod;
+private:
+  ClassType* mObj;
+  Method mMethod;
 };
 
 // Use this helper macro like so:
@@ -290,8 +310,16 @@ private:
 //
 // NOTE: Attempts to make this a template function caused VC6 to barf :-(
 //
+
 #define NS_NEW_RUNNABLE_METHOD(class_, obj_, method_) \
-    new nsRunnableMethod<class_>(obj_, &class_::method_)
+    ns_new_runnable_method(obj_, &class_::method_)
+
+template<class ClassType, typename ReturnType>
+nsRunnableMethod<ClassType, ReturnType>*
+ns_new_runnable_method(ClassType* obj, ReturnType (ClassType::*method)())
+{
+  return new nsRunnableMethod<ClassType, ReturnType>(obj, method);
+}
 
 #endif  // XPCOM_GLUE_AVOID_NSPR