From 7e1f58e993f362d5d16bd1230a4417ebb2aa07b3 Mon Sep 17 00:00:00 2001
From: Sean Feng <sefeng@mozilla.com>
Date: Thu, 13 Apr 2023 11:45:57 +0000
Subject: [PATCH] Bug 13093 - Don't change cursor when mouseover links during
 selection r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D175055
---
 dom/base/nsContentAreaDragDrop.cpp | 12 +-----------
 dom/base/nsContentUtils.cpp        | 10 ++++++++++
 dom/base/nsContentUtils.h          |  6 ++++++
 dom/events/EventStateManager.cpp   | 20 ++++++++++++++++++++
 4 files changed, 37 insertions(+), 11 deletions(-)

diff --git a/dom/base/nsContentAreaDragDrop.cpp b/dom/base/nsContentAreaDragDrop.cpp
index 00d8e47b4ca4..f99fd447f37c 100644
--- a/dom/base/nsContentAreaDragDrop.cpp
+++ b/dom/base/nsContentAreaDragDrop.cpp
@@ -332,16 +332,6 @@ static nsIContent* FindDragTarget(nsIContent* aContent) {
   return nullptr;
 }
 
-static nsIContent* FindParentLinkNode(nsIContent* aContent) {
-  for (nsIContent* content = aContent; content;
-       content = content->GetFlattenedTreeParent()) {
-    if (nsContentUtils::IsDraggableLink(content)) {
-      return content;
-    }
-  }
-  return nullptr;
-}
-
 //
 // GetAnchorURL
 //
@@ -548,7 +538,7 @@ nsresult DragDataProducer::Produce(DataTransfer* aDataTransfer, bool* aCanDrag,
       //
       // if the alt key is down, don't start a drag if we're in an
       // anchor because we want to do selection.
-      parentLink = FindParentLinkNode(draggedNode);
+      parentLink = nsContentUtils::GetClosestLinkInFlatTree(draggedNode);
       if (parentLink && mIsAltKeyPressed) {
         *aCanDrag = false;
         return NS_OK;
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index e6d15e6fd55e..6ce3947e0999 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -10997,6 +10997,16 @@ void nsContentUtils::RequestGeckoTaskBurst() {
   }
 }
 
+nsIContent* nsContentUtils::GetClosestLinkInFlatTree(nsIContent* aContent) {
+  for (nsIContent* content = aContent; content;
+       content = content->GetFlattenedTreeParent()) {
+    if (nsContentUtils::IsDraggableLink(content)) {
+      return content;
+    }
+  }
+  return nullptr;
+}
+
 namespace mozilla {
 std::ostream& operator<<(std::ostream& aOut,
                          const PreventDefaultResult aPreventDefaultResult) {
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index 6b517e2fb1a1..5e7cf91cf77f 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -3389,6 +3389,12 @@ class nsContentUtils {
     return sMayHaveFormRadioStateChangeListeners;
   }
 
+  /**
+   * Returns the closest link element in the flat tree of aContent if there's
+   * one, otherwise returns nullptr.
+   */
+  static nsIContent* GetClosestLinkInFlatTree(nsIContent* aContent);
+
  private:
   static bool InitializeEventTable();
 
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index c43058a51370..1f6454f7dac5 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -150,6 +150,21 @@ static inline int32_t RoundDown(double aDouble) {
                        : static_cast<int32_t>(ceil(aDouble));
 }
 
+static bool IsSelectingLink(nsIFrame* aTargetFrame) {
+  if (!aTargetFrame) {
+    return false;
+  }
+  const nsFrameSelection* frameSel = aTargetFrame->GetConstFrameSelection();
+  if (!frameSel || !frameSel->GetDragState()) {
+    return false;
+  }
+
+  if (!nsContentUtils::GetClosestLinkInFlatTree(aTargetFrame->GetContent())) {
+    return false;
+  }
+  return true;
+}
+
 static UniquePtr<WidgetMouseEvent> CreateMouseOrPointerWidgetEvent(
     WidgetMouseEvent* aMouseEvent, EventMessage aMessage,
     EventTarget* aRelatedTarget);
@@ -4224,6 +4239,11 @@ void EventStateManager::UpdateCursor(nsPresContext* aPresContext,
   }
 
   if (aTargetFrame) {
+    if (cursor == StyleCursorKind::Pointer && IsSelectingLink(aTargetFrame)) {
+      cursor = aTargetFrame->GetWritingMode().IsVertical()
+                   ? StyleCursorKind::VerticalText
+                   : StyleCursorKind::Text;
+    }
     SetCursor(cursor, container, resolution, hotspot,
               aTargetFrame->GetNearestWidget(), false);
     gLastCursorSourceFrame = aTargetFrame;