Bug 1192252 - Add a helper RAII class for managing the cleanup in nsFrameLoader::SwapWithOtherLoader; r=smaug

dom/base/nsFrameLoader.cpp

@@ -951,6 +951,60 @@ nsFrameLoader::SwapWithOtherRemoteLoader(nsFrameLoader* aOther,
   return NS_OK;
 }
 
+class MOZ_STACK_CLASS AutoResetInFrameSwap final
+{
+public:
+  AutoResetInFrameSwap(nsFrameLoader* aThisFrameLoader,
+                       nsFrameLoader* aOtherFrameLoader,
+                       nsDocShell* aThisDocShell,
+                       nsDocShell* aOtherDocShell,
+                       EventTarget* aThisEventTarget,
+                       EventTarget* aOtherEventTarget
+                       MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : mThisFrameLoader(aThisFrameLoader)
+    , mOtherFrameLoader(aOtherFrameLoader)
+    , mThisDocShell(aThisDocShell)
+    , mOtherDocShell(aOtherDocShell)
+    , mThisEventTarget(aThisEventTarget)
+    , mOtherEventTarget(aOtherEventTarget)
+  {
+    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+
+    mThisFrameLoader->mInSwap = true;
+    mOtherFrameLoader->mInSwap = true;
+    mThisDocShell->SetInFrameSwap(true);
+    mOtherDocShell->SetInFrameSwap(true);
+
+    // Fire pageshow events on still-loading pages, and then fire pagehide
+    // events.  Note that we do NOT fire these in the normal way, but just fire
+    // them on the chrome event handlers.
+    nsContentUtils::FirePageShowEvent(mThisDocShell, mThisEventTarget, false);
+    nsContentUtils::FirePageShowEvent(mOtherDocShell, mOtherEventTarget, false);
+    nsContentUtils::FirePageHideEvent(mThisDocShell, mThisEventTarget);
+    nsContentUtils::FirePageHideEvent(mOtherDocShell, mOtherEventTarget);
+  }
+
+  ~AutoResetInFrameSwap()
+  {
+    nsContentUtils::FirePageShowEvent(mThisDocShell, mThisEventTarget, true);
+    nsContentUtils::FirePageShowEvent(mOtherDocShell, mOtherEventTarget, true);
+
+    mThisFrameLoader->mInSwap = false;
+    mOtherFrameLoader->mInSwap = false;
+    mThisDocShell->SetInFrameSwap(false);
+    mOtherDocShell->SetInFrameSwap(false);
+  }
+
+private:
+  nsRefPtr<nsFrameLoader> mThisFrameLoader;
+  nsRefPtr<nsFrameLoader> mOtherFrameLoader;
+  nsRefPtr<nsDocShell> mThisDocShell;
+  nsRefPtr<nsDocShell> mOtherDocShell;
+  nsCOMPtr<EventTarget> mThisEventTarget;
+  nsCOMPtr<EventTarget> mOtherEventTarget;
+  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+};
+
 nsresult
 nsFrameLoader::SwapWithOtherLoader(nsFrameLoader* aOther,
                                    nsRefPtr<nsFrameLoader>& aFirstToSwap,
@@ -1119,47 +1173,23 @@ nsFrameLoader::SwapWithOtherLoader(nsFrameLoader* aOther,
   if (mInSwap || aOther->mInSwap) {
     return NS_ERROR_NOT_IMPLEMENTED;
   }
-  mInSwap = aOther->mInSwap = true;
-  ourDocshell->SetInFrameSwap(true);
-  otherDocshell->SetInFrameSwap(true);
+  AutoResetInFrameSwap autoFrameSwap(this, aOther, ourDocshell, otherDocshell,
+                                     ourEventTarget, otherEventTarget);
 
-  // Fire pageshow events on still-loading pages, and then fire pagehide
-  // events.  Note that we do NOT fire these in the normal way, but just fire
-  // them on the chrome event handlers.
-  nsContentUtils::FirePageShowEvent(ourDocshell, ourEventTarget, false);
-  nsContentUtils::FirePageShowEvent(otherDocshell, otherEventTarget, false);
-  nsContentUtils::FirePageHideEvent(ourDocshell, ourEventTarget);
-  nsContentUtils::FirePageHideEvent(otherDocshell, otherEventTarget);
-  
   nsIFrame* ourFrame = ourContent->GetPrimaryFrame();
   nsIFrame* otherFrame = otherContent->GetPrimaryFrame();
   if (!ourFrame || !otherFrame) {
-    nsContentUtils::FirePageShowEvent(ourDocshell, ourEventTarget, true);
-    nsContentUtils::FirePageShowEvent(otherDocshell, otherEventTarget, true);
-    mInSwap = aOther->mInSwap = false;
-    ourDocshell->SetInFrameSwap(false);
-    otherDocshell->SetInFrameSwap(false);
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
   nsSubDocumentFrame* ourFrameFrame = do_QueryFrame(ourFrame);
   if (!ourFrameFrame) {
-    nsContentUtils::FirePageShowEvent(ourDocshell, ourEventTarget, true);
-    nsContentUtils::FirePageShowEvent(otherDocshell, otherEventTarget, true);
-    mInSwap = aOther->mInSwap = false;
-    ourDocshell->SetInFrameSwap(false);
-    otherDocshell->SetInFrameSwap(false);
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
   // OK.  First begin to swap the docshells in the two nsIFrames
   rv = ourFrameFrame->BeginSwapDocShells(otherFrame);
   if (NS_FAILED(rv)) {
-    nsContentUtils::FirePageShowEvent(ourDocshell, ourEventTarget, true);
-    nsContentUtils::FirePageShowEvent(otherDocshell, otherEventTarget, true);
-    mInSwap = aOther->mInSwap = false;
-    ourDocshell->SetInFrameSwap(false);
-    otherDocshell->SetInFrameSwap(false);
     return rv;
   }
 
@@ -1262,12 +1292,6 @@ nsFrameLoader::SwapWithOtherLoader(nsFrameLoader* aOther,
   ourParentDocument->FlushPendingNotifications(Flush_Layout);
   otherParentDocument->FlushPendingNotifications(Flush_Layout);
 
-  nsContentUtils::FirePageShowEvent(ourDocshell, ourEventTarget, true);
-  nsContentUtils::FirePageShowEvent(otherDocshell, otherEventTarget, true);
-
-  mInSwap = aOther->mInSwap = false;
-  ourDocshell->SetInFrameSwap(false);
-  otherDocshell->SetInFrameSwap(false);
   return NS_OK;
 }
 

dom/base/nsFrameLoader.h

@@ -31,6 +31,7 @@ class nsSubDocumentFrame;
 class nsView;
 class nsIInProcessContentFrameMessageManager;
 class AutoResetInShow;
+class AutoResetInFrameSwap;
 class nsITabParent;
 class nsIDocShellTreeItem;
 class nsIDocShellTreeOwner;
@@ -59,6 +60,7 @@ class nsFrameLoader final : public nsIFrameLoader,
                             public mozilla::dom::ipc::MessageManagerCallback
 {
   friend class AutoResetInShow;
+  friend class AutoResetInFrameSwap;
   typedef mozilla::dom::PBrowserParent PBrowserParent;
   typedef mozilla::dom::TabParent TabParent;
   typedef mozilla::layout::RenderFrameParent RenderFrameParent;