From 65e6de2b59ed290c2fddfdd58eb1156cc0ea92b0 Mon Sep 17 00:00:00 2001
From: Hiroyuki Ikezoe <hikezoe.birchill@mozilla.com>
Date: Tue, 30 Aug 2022 06:49:59 +0000
Subject: [PATCH] Bug 1704978 - Prevent opening context menu in the case the
 user did right click in the overscroll gutter on Windows. r=botond,handyman

Differential Revision: https://phabricator.services.mozilla.com/D155039
---
 ...helper_hittest_overscroll_contextmenu.html |  5 ----
 widget/windows/nsWindow.cpp                   | 24 ++++++++++++++++++-
 widget/windows/nsWindow.h                     | 23 ++++++++++++++++++
 3 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/gfx/layers/apz/test/mochitest/helper_hittest_overscroll_contextmenu.html b/gfx/layers/apz/test/mochitest/helper_hittest_overscroll_contextmenu.html
index c6b80103392d..8aff3103ddc9 100644
--- a/gfx/layers/apz/test/mochitest/helper_hittest_overscroll_contextmenu.html
+++ b/gfx/layers/apz/test/mochitest/helper_hittest_overscroll_contextmenu.html
@@ -78,11 +78,6 @@ async function test() {
   var config = getHitTestConfig();
   var utils = config.utils;
 
-  if (config.isWindows) {
-    todo(false, "This test does not yet work on Windows");
-    return;
-  }
-
   // Overscroll the root scroll frame at the top, creating a gutter.
   // Note that the size of the gutter will only be 8px, because
   // setAsyncScrollOffset() applies the overscroll as a single delta,
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index 76eeeade02d7..615b671badaa 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -4479,6 +4479,7 @@ bool nsWindow::DispatchMouseEvent(EventMessage aEventMessage, WPARAM wParam,
                                   int16_t aButton, uint16_t aInputSource,
                                   WinPointerInfo* aPointerInfo,
                                   bool aIgnoreAPZ) {
+  ContextMenuPreventer contextMenuPreventer(this);
   bool result = false;
 
   UserActivity();
@@ -4695,7 +4696,10 @@ bool nsWindow::DispatchMouseEvent(EventMessage aEventMessage, WPARAM wParam,
       }
     }
 
-    return ConvertStatus(DispatchInputEvent(&event).mContentStatus);
+    nsIWidget::ContentAndAPZEventStatus eventStatus =
+        DispatchInputEvent(&event);
+    contextMenuPreventer.Update(event, eventStatus);
+    return ConvertStatus(eventStatus.mContentStatus);
   }
 
   return result;
@@ -5787,6 +5791,14 @@ bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
         break;
       }
 
+      // If this WM_CONTEXTMENU is triggered by a mouse's secondary button up
+      // event in overscroll gutter, we shouldn't open context menu.
+      if (MOUSE_INPUT_SOURCE() == MouseEvent_Binding::MOZ_SOURCE_MOUSE &&
+          mNeedsToPreventContextMenu) {
+        result = true;
+        break;
+      }
+
       // if the context menu is brought up from the keyboard, |lParam|
       // will be -1.
       LPARAM pos;
@@ -9435,3 +9447,13 @@ void nsWindow::FrameState::SetSizeModeInternal(nsSizeMode aMode) {
     mWindow->DispatchFocusToTopLevelWindow(true);
   }
 }
+
+void nsWindow::ContextMenuPreventer::Update(
+    const WidgetMouseEvent& aEvent,
+    const nsIWidget::ContentAndAPZEventStatus& aEventStatus) {
+  mNeedsToPreventContextMenu =
+      aEvent.mMessage == eMouseUp &&
+      aEvent.mButton == MouseButton::eSecondary &&
+      aEvent.mInputSource == MouseEvent_Binding::MOZ_SOURCE_MOUSE &&
+      aEventStatus.mApzStatus == nsEventStatus_eConsumeNoDefault;
+}
diff --git a/widget/windows/nsWindow.h b/widget/windows/nsWindow.h
index 42747415971c..93f8d88ab0b4 100644
--- a/widget/windows/nsWindow.h
+++ b/widget/windows/nsWindow.h
@@ -64,6 +64,7 @@ class nsIRollupListener;
 class imgIContainer;
 
 namespace mozilla {
+class WidgetMouseEvent;
 namespace widget {
 class NativeKey;
 class InProcessWinCompositorWidget;
@@ -876,6 +877,28 @@ class nsWindow final : public nsBaseWidget {
   // process after the Compositor is created
   bool mRequestFxrOutputPending = false;
 
+  // A stack based class used in DispatchMouseEvent() to tell whether we should
+  // NOT open context menu when we receives WM_CONTEXTMENU after the
+  // DispatchMouseEvent calls.
+  // This class now works only in the case where a mouse up event happened in
+  // the overscroll gutter.
+  class MOZ_STACK_CLASS ContextMenuPreventer final {
+   public:
+    explicit ContextMenuPreventer(nsWindow* aWindow)
+        : mWindow(aWindow), mNeedsToPreventContextMenu(false){};
+    ~ContextMenuPreventer() {
+      mWindow->mNeedsToPreventContextMenu = mNeedsToPreventContextMenu;
+    }
+    void Update(const mozilla::WidgetMouseEvent& aEvent,
+                const nsIWidget::ContentAndAPZEventStatus& aEventStatus);
+
+   private:
+    nsWindow* mWindow;
+    bool mNeedsToPreventContextMenu = false;
+  };
+  friend class ContextMenuPreventer;
+  bool mNeedsToPreventContextMenu = false;
+
   mozilla::UniquePtr<mozilla::widget::DirectManipulationOwner> mDmOwner;
 
   // Client rect for minimize, maximize and close buttons.