Bug 1558215 - Refactor nsPIDOMWindowInner::AddAfterLoadRunner to be easier to use, r=baku

Differential Revision: https://phabricator.services.mozilla.com/D34366

--HG--
extra : moz-landing-system : lando

dom/base/nsGlobalWindowInner.cpp

@@ -1052,6 +1052,8 @@ nsGlobalWindowInner::~nsGlobalWindowInner() {
   nsCOMPtr<nsIDeviceSensors> ac = do_GetService(NS_DEVICE_SENSORS_CONTRACTID);
   if (ac) ac->RemoveWindowAsListener(this);
 
+  mDeprioritizedLoadRunner.clear();
+
   nsLayoutStatics::Release();
 }
 
@@ -2546,7 +2548,7 @@ void nsPIDOMWindowInner::SetAudioCapture(bool aCapture) {
   }
 }
 
-void nsPIDOMWindowInner::SetActiveLoadingState(bool aIsLoading) {
+void nsGlobalWindowInner::SetActiveLoadingState(bool aIsLoading) {
   if (StaticPrefs::dom_separate_event_queue_for_post_message_enabled()) {
     if (!aIsLoading) {
       Document* doc = GetExtantDoc();
@@ -2564,15 +2566,33 @@ void nsPIDOMWindowInner::SetActiveLoadingState(bool aIsLoading) {
   }
 
   if (!aIsLoading) {
-    for (uint32_t i = 0; i < mAfterLoadRunners.Length(); ++i) {
-      NS_DispatchToCurrentThread(mAfterLoadRunners[i].forget());
+    while (!mDeprioritizedLoadRunner.isEmpty()) {
+      nsCOMPtr<nsIRunnable> runner = mDeprioritizedLoadRunner.popFirst();
+      NS_DispatchToCurrentThread(runner.forget());
     }
-    mAfterLoadRunners.Clear();
   }
 }
 
-void nsPIDOMWindowInner::AddAfterLoadRunner(nsIRunnable* aRunner) {
-  mAfterLoadRunners.AppendElement(aRunner);
+nsPIDOMWindowInner* nsPIDOMWindowInner::GetWindowForDeprioritizedLoadRunner() {
+  Document* doc = GetExtantDoc();
+  if (!doc) {
+    return nullptr;
+  }
+  doc = doc->GetTopLevelContentDocument();
+  if (!doc || (doc->GetReadyStateEnum() <= Document::READYSTATE_UNINITIALIZED ||
+               doc->GetReadyStateEnum() >= Document::READYSTATE_COMPLETE)) {
+    return nullptr;
+  }
+
+  return doc->GetInnerWindow();
+}
+
+void nsGlobalWindowInner::AddDeprioritizedLoadRunner(nsIRunnable* aRunner) {
+  MOZ_ASSERT(GetWindowForDeprioritizedLoadRunner() == this);
+  RefPtr<DeprioritizedLoadRunner> runner = new DeprioritizedLoadRunner(aRunner);
+  mDeprioritizedLoadRunner.insertBack(runner);
+  NS_DispatchToCurrentThreadQueue(runner.forget(), 5000,
+                                  EventQueuePriority::Idle);
 }
 
 // nsISpeechSynthesisGetter

dom/base/nsGlobalWindowInner.h

@@ -58,6 +58,7 @@
 #include "mozilla/dom/ImageBitmapSource.h"
 #include "mozilla/UniquePtr.h"
 #include "nsRefreshDriver.h"
+#include "nsThreadUtils.h"
 
 class nsIArray;
 class nsIBaseWindow;
@@ -1226,6 +1227,9 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   typedef mozilla::LinkedList<RefPtr<mozilla::dom::IdleRequest>> IdleRequests;
   void RemoveIdleCallback(mozilla::dom::IdleRequest* aRequest);
 
+  void SetActiveLoadingState(bool aIsLoading) override;
+  void AddDeprioritizedLoadRunner(nsIRunnable* aRunner) override;
+
  protected:
   // Window offline status. Checked to see if we need to fire offline event
   bool mWasOffline : 1;
@@ -1397,6 +1401,28 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   nsTArray<mozilla::UniquePtr<PromiseDocumentFlushedResolver>>
       mDocumentFlushedResolvers;
 
+  class DeprioritizedLoadRunner
+      : public mozilla::Runnable,
+        public mozilla::LinkedListElement<DeprioritizedLoadRunner> {
+   public:
+    explicit DeprioritizedLoadRunner(nsIRunnable* aInner)
+        : Runnable("DeprioritizedLoadRunner"), mInner(aInner) {}
+
+    NS_IMETHOD Run() override {
+      if (mInner) {;
+        RefPtr<nsIRunnable> inner = std::move(mInner);
+        inner->Run();
+      }
+
+      return NS_OK;
+    }
+
+   private:
+    RefPtr<nsIRunnable> mInner;
+  };
+
+  mozilla::LinkedList<DeprioritizedLoadRunner> mDeprioritizedLoadRunner;
+
   static InnerWindowByIdTable* sInnerWindowsById;
 
   // Members in the mChromeFields member should only be used in chrome windows.

dom/base/nsPIDOMWindow.h

@@ -175,8 +175,17 @@ class nsPIDOMWindowInner : public mozIDOMWindow {
   inline bool IsHandlingResizeEvent() const;
 
   // Note: not related to IsLoading.  Set to false if there's an error, etc.
-  void SetActiveLoadingState(bool aIsActiveLoading);
-  void AddAfterLoadRunner(nsIRunnable* aRunner);
+  virtual void SetActiveLoadingState(bool aIsActiveLoading) = 0;
+
+  nsPIDOMWindowInner* GetWindowForDeprioritizedLoadRunner();
+
+  /**
+   * The runnable will be called once there is idle time, or the top level
+   * page has been loaded or if a timeout has fired.
+   * Must be called only on the top level window, the one
+   * GetWindowForDeprioritizedLoadRunner returns.
+   */
+  virtual void AddDeprioritizedLoadRunner(nsIRunnable* aRunner) = 0;
 
   bool AddAudioContext(mozilla::dom::AudioContext* aAudioContext);
   void RemoveAudioContext(mozilla::dom::AudioContext* aAudioContext);
@@ -677,8 +686,6 @@ class nsPIDOMWindowInner : public mozIDOMWindow {
   // This will be non-null during the full lifetime of the window, initialized
   // during SetNewDocument, and cleared during FreeInnerObjects.
   RefPtr<mozilla::dom::WindowGlobalChild> mWindowGlobalChild;
-
-  nsTArray<nsCOMPtr<nsIRunnable>> mAfterLoadRunners;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsPIDOMWindowInner, NS_PIDOMWINDOWINNER_IID)

dom/xhr/XMLHttpRequestMainThread.cpp

@@ -2255,22 +2255,15 @@ void XMLHttpRequestMainThread::ChangeStateToDone(bool aWasSync) {
     mChannel->GetLoadFlags(&loadFlags);
     if (loadFlags & nsIRequest::LOAD_BACKGROUND) {
       nsPIDOMWindowInner* owner = GetOwner();
-      Document* doc = owner ? owner->GetExtantDoc() : nullptr;
-      doc = doc ? doc->GetTopLevelContentDocument() : nullptr;
-      if (doc &&
-          (doc->GetReadyStateEnum() > Document::READYSTATE_UNINITIALIZED &&
-           doc->GetReadyStateEnum() < Document::READYSTATE_COMPLETE)) {
-        nsPIDOMWindowInner* topWin = doc->GetInnerWindow();
-        if (topWin) {
-          MOZ_ASSERT(!mDelayedDoneNotifier);
-          RefPtr<XMLHttpRequestDoneNotifier> notifier =
-              new XMLHttpRequestDoneNotifier(this);
-          mDelayedDoneNotifier = notifier;
-          topWin->AddAfterLoadRunner(notifier);
-          NS_DispatchToCurrentThreadQueue(notifier.forget(), 5000,
-                                          EventQueuePriority::Idle);
-          return;
-        }
+      nsPIDOMWindowInner* topWin =
+          owner ? owner->GetWindowForDeprioritizedLoadRunner() : nullptr;
+      if (topWin) {
+        MOZ_ASSERT(!mDelayedDoneNotifier);
+        RefPtr<XMLHttpRequestDoneNotifier> notifier =
+            new XMLHttpRequestDoneNotifier(this);
+        mDelayedDoneNotifier = notifier;
+        topWin->AddDeprioritizedLoadRunner(notifier);
+        return;
       }
     }
   }