Bug 1809122 - Track top-level window context in DragSession; r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D169121

dom/base/ContentAreaDropListener.jsm

@@ -248,15 +248,15 @@ ContentAreaDropListener.prototype = {
     }
 
     // If this is an external drag, allow drop.
-    let sourceWC = dataTransfer.sourceWindowContext;
-    if (!sourceWC) {
+    let sourceTopWC = dataTransfer.sourceTopWindowContext;
+    if (!sourceTopWC) {
       return true;
     }
 
     // If drag source and drop target are in the same top window, don't allow.
     let eventWC =
       aEvent.originalTarget.ownerGlobal.browsingContext.currentWindowContext;
-    if (eventWC && sourceWC.topWindowContext == eventWC.topWindowContext) {
+    if (eventWC && sourceTopWC == eventWC.topWindowContext) {
       return false;
     }
 

dom/events/DataTransfer.cpp

@@ -440,15 +440,16 @@ already_AddRefed<nsINode> DataTransfer::GetMozSourceNode() {
   return sourceNode.forget();
 }
 
-already_AddRefed<WindowContext> DataTransfer::GetSourceWindowContext() {
+already_AddRefed<WindowContext> DataTransfer::GetSourceTopWindowContext() {
   nsCOMPtr<nsIDragSession> dragSession = nsContentUtils::GetDragSession();
   if (!dragSession) {
     return nullptr;
   }
 
-  RefPtr<WindowContext> sourceWindowContext;
-  dragSession->GetSourceWindowContext(getter_AddRefs(sourceWindowContext));
-  return sourceWindowContext.forget();
+  RefPtr<WindowContext> sourceTopWindowContext;
+  dragSession->GetSourceTopWindowContext(
+      getter_AddRefs(sourceTopWindowContext));
+  return sourceTopWindowContext.forget();
 }
 
 already_AddRefed<DOMStringList> DataTransfer::MozTypesAt(

dom/events/DataTransfer.h

@@ -255,7 +255,7 @@ class DataTransfer final : public nsISupports, public nsWrapperCache {
 
   already_AddRefed<nsINode> GetMozSourceNode();
 
-  already_AddRefed<WindowContext> GetSourceWindowContext();
+  already_AddRefed<WindowContext> GetSourceTopWindowContext();
 
   /*
    * Integer version of dropEffect, set to one of the constants in

dom/events/RemoteDragStartData.cpp

@@ -23,14 +23,15 @@ RemoteDragStartData::RemoteDragStartData(
     BrowserParent* aBrowserParent, nsTArray<IPCDataTransfer>&& aDataTransfer,
     const LayoutDeviceIntRect& aRect, nsIPrincipal* aPrincipal,
     nsIContentSecurityPolicy* aCsp, nsICookieJarSettings* aCookieJarSettings,
-    WindowContext* aSourceWindowContext)
+    WindowContext* aSourceWindowContext, WindowContext* aSourceTopWindowContext)
     : mBrowserParent(aBrowserParent),
       mDataTransfer(std::move(aDataTransfer)),
       mRect(aRect),
       mPrincipal(aPrincipal),
       mCsp(aCsp),
       mCookieJarSettings(aCookieJarSettings),
-      mSourceWindowContext(aSourceWindowContext) {}
+      mSourceWindowContext(aSourceWindowContext),
+      mSourceTopWindowContext(aSourceTopWindowContext) {}
 
 void RemoteDragStartData::AddInitialDnDDataTo(
     DataTransfer* aDataTransfer, nsIPrincipal** aPrincipal,

dom/events/RemoteDragStartData.h

@@ -31,7 +31,8 @@ class RemoteDragStartData {
                       const LayoutDeviceIntRect& aRect,
                       nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
                       nsICookieJarSettings* aCookieJarSettings,
-                      WindowContext* aSourceWindowContext);
+                      WindowContext* aSourceWindowContext,
+                      WindowContext* aSourceTopWindowContext);
 
   void SetVisualization(
       already_AddRefed<gfx::DataSourceSurface> aVisualization) {
@@ -52,6 +53,7 @@ class RemoteDragStartData {
                            nsICookieJarSettings** aCookieJarSettings);
 
   WindowContext* GetSourceWindowContext() { return mSourceWindowContext; }
+  WindowContext* GetSourceTopWindowContext() { return mSourceTopWindowContext; }
 
  private:
   virtual ~RemoteDragStartData();
@@ -63,6 +65,7 @@ class RemoteDragStartData {
   nsCOMPtr<nsIContentSecurityPolicy> mCsp;
   nsCOMPtr<nsICookieJarSettings> mCookieJarSettings;
   RefPtr<WindowContext> mSourceWindowContext;
+  RefPtr<WindowContext> mSourceTopWindowContext;
   RefPtr<mozilla::gfx::SourceSurface> mVisualization;
 };
 

dom/ipc/BrowserParent.cpp

@@ -3746,7 +3746,8 @@ mozilla::ipc::IPCResult BrowserParent::RecvInvokeDragSession(
     const gfx::SurfaceFormat& aFormat, const LayoutDeviceIntRect& aDragRect,
     nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
     const CookieJarSettingsArgs& aCookieJarSettingsArgs,
-    const MaybeDiscarded<WindowContext>& aSourceWindowContext) {
+    const MaybeDiscarded<WindowContext>& aSourceWindowContext,
+    const MaybeDiscarded<WindowContext>& aSourceTopWindowContext) {
   PresShell* presShell = mFrameElement->OwnerDoc()->GetPresShell();
   if (!presShell) {
     Unused << Manager()->SendEndDragSession(
@@ -3764,7 +3765,8 @@ mozilla::ipc::IPCResult BrowserParent::RecvInvokeDragSession(
 
   RefPtr<RemoteDragStartData> dragStartData = new RemoteDragStartData(
       this, std::move(aTransfers), aDragRect, aPrincipal, aCsp,
-      cookieJarSettings, aSourceWindowContext.GetMaybeDiscarded());
+      cookieJarSettings, aSourceWindowContext.GetMaybeDiscarded(),
+      aSourceTopWindowContext.GetMaybeDiscarded());
 
   if (aVisualDnDData && aVisualDnDData->Size() >= aDragRect.height * aStride) {
     dragStartData->SetVisualization(gfx::CreateDataSourceSurfaceFromData(

dom/ipc/BrowserParent.h

@@ -674,7 +674,8 @@ class BrowserParent final : public PBrowserParent,
       const gfx::SurfaceFormat& aFormat, const LayoutDeviceIntRect& aDragRect,
       nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
       const CookieJarSettingsArgs& aCookieJarSettingsArgs,
-      const MaybeDiscarded<WindowContext>& aSourceWindowContext);
+      const MaybeDiscarded<WindowContext>& aSourceWindowContext,
+      const MaybeDiscarded<WindowContext>& aSourceTopWindowContext);
 
   void AddInitialDnDDataTo(DataTransfer* aDataTransfer,
                            nsIPrincipal** aPrincipal);

dom/ipc/ContentChild.cpp

@@ -3184,6 +3184,7 @@ bool ContentChild::DeallocPWebBrowserPersistDocumentChild(
 
 mozilla::ipc::IPCResult ContentChild::RecvInvokeDragSession(
     const MaybeDiscarded<WindowContext>& aSourceWindowContext,
+    const MaybeDiscarded<WindowContext>& aSourceTopWindowContext,
     nsTArray<IPCDataTransfer>&& aTransfers, const uint32_t& aAction) {
   nsCOMPtr<nsIDragService> dragService =
       do_GetService("@mozilla.org/widget/dragservice;1");
@@ -3193,6 +3194,8 @@ mozilla::ipc::IPCResult ContentChild::RecvInvokeDragSession(
     dragService->GetCurrentSession(getter_AddRefs(session));
     if (session) {
       session->SetSourceWindowContext(aSourceWindowContext.GetMaybeDiscarded());
+      session->SetSourceTopWindowContext(
+          aSourceTopWindowContext.GetMaybeDiscarded());
       session->SetDragAction(aAction);
       // Check if we are receiving any file objects. If we are we will want
       // to hide any of the other objects coming in from content.

dom/ipc/ContentChild.h

@@ -413,6 +413,7 @@ class ContentChild final : public PContentChild,
 
   mozilla::ipc::IPCResult RecvInvokeDragSession(
       const MaybeDiscarded<WindowContext>& aSourceWindowContext,
+      const MaybeDiscarded<WindowContext>& aSourceTopWindowContext,
       nsTArray<IPCDataTransfer>&& aTransfers, const uint32_t& aAction);
 
   MOZ_CAN_RUN_SCRIPT_BOUNDARY

dom/ipc/ContentParent.cpp

@@ -5444,8 +5444,10 @@ void ContentParent::MaybeInvokeDragSession(BrowserParent* aParent) {
 
       RefPtr<WindowContext> sourceWC;
       session->GetSourceWindowContext(getter_AddRefs(sourceWC));
+      RefPtr<WindowContext> sourceTopWC;
+      session->GetSourceTopWindowContext(getter_AddRefs(sourceTopWC));
       mozilla::Unused << SendInvokeDragSession(
-          sourceWC, std::move(dataTransfers), action);
+          sourceWC, sourceTopWC, std::move(dataTransfers), action);
     }
   }
 }

dom/ipc/PBrowser.ipdl

@@ -628,7 +628,8 @@ parent:
                             LayoutDeviceIntRect dragRect,
                             nsIPrincipal principal, nsIContentSecurityPolicy csp,
                             CookieJarSettingsArgs cookieJarSettings,
-                            MaybeDiscardedWindowContext sourceWindowContext);
+                            MaybeDiscardedWindowContext sourceWindowContext,
+                            MaybeDiscardedWindowContext sourceTopWindowContext);
 
     // After a compositor reset, it is necessary to reconnect each layers ID to
     // the compositor of the widget that will render those layers. Note that

dom/ipc/PContent.ipdl

@@ -815,7 +815,8 @@ child:
      */
     async NotifyIdleObserver(uint64_t observerId, nsCString topic, nsString str);
 
-    async InvokeDragSession(MaybeDiscardedWindowContext aContext,
+    async InvokeDragSession(MaybeDiscardedWindowContext aSourceWindowContext,
+                            MaybeDiscardedWindowContext aSourceTopWindowContext,
                             IPCDataTransfer[] transfers, uint32_t action);
 
     async EndDragSession(bool aDoneDrag, bool aUserCancelled,

dom/webidl/DataTransfer.webidl

@@ -152,11 +152,11 @@ partial interface DataTransfer {
   readonly attribute Node? mozSourceNode;
 
   /**
-   * The window context that mouse was pressed over to begin the drag. For
-   * external drags, this will be null.
+   * The top-level window context that mouse was pressed over to begin the drag.
+   * For external drags, this will be null.
    */
   [ChromeOnly]
-  readonly attribute WindowContext? sourceWindowContext;
+  readonly attribute WindowContext? sourceTopWindowContext;
 
   /**
    * The URI spec of the triggering principal.  This may be different than

widget/nsBaseDragService.cpp

@@ -150,6 +150,29 @@ nsBaseDragService::SetSourceWindowContext(WindowContext* aSourceWindowContext) {
   return NS_OK;
 }
 
+//
+// GetSourceTopWindowContext
+//
+// Returns the top-level window context where the drag was initiated. This will
+// be nullptr if the drag began outside of our application.
+//
+NS_IMETHODIMP
+nsBaseDragService::GetSourceTopWindowContext(
+    WindowContext** aSourceTopWindowContext) {
+  *aSourceTopWindowContext = mSourceTopWindowContext.get();
+  NS_IF_ADDREF(*aSourceTopWindowContext);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetSourceTopWindowContext(
+    WindowContext* aSourceTopWindowContext) {
+  // This should only be called in a child process.
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  mSourceTopWindowContext = aSourceTopWindowContext;
+  return NS_OK;
+}
+
 //
 // GetSourceNode
 //
@@ -393,6 +416,8 @@ nsBaseDragService::InvokeDragSessionWithImage(
   mDragStartData = nullptr;
   mSourceWindowContext =
       aDOMNode ? aDOMNode->OwnerDoc()->GetWindowContext() : nullptr;
+  mSourceTopWindowContext =
+      mSourceWindowContext ? mSourceWindowContext->TopWindowContext() : nullptr;
 
   mScreenPosition = aDragEvent->ScreenPoint(CallerType::System);
   mInputSource = aDragEvent->MozInputSource();
@@ -441,6 +466,7 @@ nsBaseDragService::InvokeDragSessionWithRemoteImage(
   mDragStartData = aDragStartData;
   mImageOffset = CSSIntPoint(0, 0);
   mSourceWindowContext = mDragStartData->GetSourceWindowContext();
+  mSourceTopWindowContext = mDragStartData->GetSourceTopWindowContext();
 
   mScreenPosition = aDragEvent->ScreenPoint(CallerType::System);
   mInputSource = aDragEvent->MozInputSource();
@@ -482,6 +508,8 @@ nsBaseDragService::InvokeDragSessionWithSelection(
   // endpoints of the selection
   nsCOMPtr<nsINode> node = aSelection->GetFocusNode();
   mSourceWindowContext = node ? node->OwnerDoc()->GetWindowContext() : nullptr;
+  mSourceTopWindowContext =
+      mSourceWindowContext ? mSourceWindowContext->TopWindowContext() : nullptr;
 
   return InvokeDragSession(node, aPrincipal, aCsp, aCookieJarSettings,
                            aTransferableArray, aActionType,

widget/nsBaseDragService.h

@@ -170,6 +170,7 @@ class nsBaseDragService : public nsIDragService, public nsIDragSession {
   RefPtr<mozilla::dom::Document> mSourceDocument;
 
   RefPtr<mozilla::dom::WindowContext> mSourceWindowContext;
+  RefPtr<mozilla::dom::WindowContext> mSourceTopWindowContext;
 
   // the contentpolicy type passed to the channel when initiating the drag
   // session

widget/nsDragServiceProxy.cpp

@@ -46,7 +46,12 @@ nsresult nsDragServiceProxy::InvokeDragSessionImpl(
   nsCOMPtr<nsIContentSecurityPolicy> csp;
   if (mSourceDocument) {
     csp = mSourceDocument->GetCsp();
+    // XXX why do we need this here? Shouldn't they be set properly in
+    // nsBaseDragService already?
     mSourceWindowContext = mSourceDocument->GetWindowContext();
+    mSourceTopWindowContext = mSourceWindowContext
+                                  ? mSourceWindowContext->TopWindowContext()
+                                  : nullptr;
   }
 
   nsCOMPtr<nsICookieJarSettings> cookieJarSettings;
@@ -75,7 +80,7 @@ nsresult nsDragServiceProxy::InvokeDragSessionImpl(
         mozilla::Unused << child->SendInvokeDragSession(
             std::move(dataTransfers), aActionType, std::move(surfaceData),
             stride, dataSurface->GetFormat(), dragRect, principal, csp, csArgs,
-            mSourceWindowContext);
+            mSourceWindowContext, mSourceTopWindowContext);
         StartDragSession();
         return NS_OK;
       }
@@ -85,7 +90,7 @@ nsresult nsDragServiceProxy::InvokeDragSessionImpl(
   mozilla::Unused << child->SendInvokeDragSession(
       std::move(dataTransfers), aActionType, Nothing(), 0,
       static_cast<SurfaceFormat>(0), dragRect, principal, csp, csArgs,
-      mSourceWindowContext);
+      mSourceWindowContext, mSourceTopWindowContext);
   StartDragSession();
   return NS_OK;
 }

widget/nsIDragSession.idl

@@ -53,6 +53,14 @@ interface nsIDragSession : nsISupports
   [infallible]
   attribute WindowContext sourceWindowContext;
 
+  /**
+    * The top-level window context where the drag was started, which will be
+    * null if the drag originated outside the application. Useful for
+    * determining if a drop originated in the same top-level window context.
+    */
+  [infallible]
+  attribute WindowContext sourceTopWindowContext;
+
   /**
     * The dom node that was originally dragged to start the session, which will be null if the
     * drag originated outside the application.