Bug 1898343 - Don't fire selectionchange if there is one pending, r=masayuki

Differential Revision: https://phabricator.services.mozilla.com/D211263

devtools/client/inspector/fonts/test/browser_fontinspector_reveal-in-page.js

@@ -23,9 +23,7 @@ async function testFontHighlighting(view) {
   // The number of window selection change events we expect to get as we hover over each
   // font in the list. Waiting for those events is how we know that text-runs were
   // highlighted in the page.
-  // The reason why these numbers vary is because the highlighter may create more than
-  // 1 selection range object, depending on the number of text-runs found.
-  const expectedSelectionChangeEvents = [2, 2, 2, 1, 1];
+  const expectedSelectionChangeEvents = [1, 1, 1, 1, 1];
 
   const viewDoc = view.document;
 

dom/base/SelectionChangeEventDispatcher.cpp

@@ -164,12 +164,21 @@ void SelectionChangeEventDispatcher::OnSelectionChange(Document* aDoc,
 
   nsINode* target =
       textControl ? static_cast<nsINode*>(textControl.get()) : aDoc;
-  if (target) {
-    CanBubble canBubble = textControl ? CanBubble::eYes : CanBubble::eNo;
-    RefPtr<AsyncEventDispatcher> asyncDispatcher =
-        new AsyncEventDispatcher(target, eSelectionChange, canBubble);
-    asyncDispatcher->PostDOMEvent();
+  if (!target) {
+    return;
   }
+
+  if (target->HasScheduledSelectionChangeEvent()) {
+    return;
+  }
+
+  target->SetHasScheduledSelectionChangeEvent();
+
+  CanBubble canBubble = textControl ? CanBubble::eYes : CanBubble::eNo;
+  RefPtr<AsyncEventDispatcher> asyncDispatcher =
+      new AsyncSelectionChangeEventDispatcher(target, eSelectionChange,
+                                              canBubble);
+  asyncDispatcher->PostDOMEvent();
 }
 
 }  // namespace mozilla

dom/base/nsINode.h

@@ -164,8 +164,10 @@ enum : uint32_t {
 
   NODE_MAY_HAVE_ELEMENT_CHILDREN = NODE_FLAG_BIT(12),
 
+  NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT = NODE_FLAG_BIT(13),
+
   // Remaining bits are node type specific.
-  NODE_TYPE_SPECIFIC_BITS_OFFSET = 13
+  NODE_TYPE_SPECIFIC_BITS_OFFSET = 14
 };
 
 // Flags for selectors that persist to the DOM node.
@@ -1642,6 +1644,18 @@ class nsINode : public mozilla::dom::EventTarget {
   MOZ_CAN_RUN_SCRIPT nsIContent* GetSelectionRootContent(
       mozilla::PresShell* aPresShell, bool aAllowCrossShadowBoundary = false);
 
+  bool HasScheduledSelectionChangeEvent() {
+    return HasFlag(NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT);
+  }
+
+  void SetHasScheduledSelectionChangeEvent() {
+    SetFlags(NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT);
+  }
+
+  void ClearHasScheduledSelectionChangeEvent() {
+    UnsetFlags(NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT);
+  }
+
   nsINodeList* ChildNodes();
 
   nsIContent* GetFirstChild() const { return mFirstChild; }

dom/events/AsyncEventDispatcher.h

@@ -205,6 +205,19 @@ class LoadBlockingAsyncEventDispatcher final : public AsyncEventDispatcher {
   RefPtr<dom::Document> mBlockedDoc;
 };
 
+class AsyncSelectionChangeEventDispatcher : public AsyncEventDispatcher {
+ public:
+  AsyncSelectionChangeEventDispatcher(dom::EventTarget* aTarget,
+                                      EventMessage aEventMessage,
+                                      CanBubble aCanBubble)
+      : AsyncEventDispatcher(aTarget, aEventMessage, aCanBubble) {}
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHOD Run() override {
+    mTarget->GetAsNode()->ClearHasScheduledSelectionChangeEvent();
+    return AsyncEventDispatcher::Run();
+  }
+};
+
 }  // namespace mozilla
 
 #endif  // mozilla_AsyncEventDispatcher_h_

dom/html/TextControlState.cpp

@@ -2116,8 +2116,10 @@ void TextControlState::SetSelectionRange(uint32_t aStart, uint32_t aEnd,
   // XXX(krosylight): Shouldn't it fire before select event?
   // Currently Gecko and Blink both fire selectionchange after select.
   if (IsSelectionCached() &&
-      StaticPrefs::dom_select_events_textcontrols_selectionchange_enabled()) {
-    asyncDispatcher = new AsyncEventDispatcher(
+      StaticPrefs::dom_select_events_textcontrols_selectionchange_enabled() &&
+      !mTextCtrlElement->HasScheduledSelectionChangeEvent()) {
+    mTextCtrlElement->SetHasScheduledSelectionChangeEvent();
+    asyncDispatcher = new AsyncSelectionChangeEventDispatcher(
         mTextCtrlElement, eSelectionChange, CanBubble::eYes);
     asyncDispatcher->PostDOMEvent();
   }

dom/tests/mochitest/general/frameSelectEvents.html

@@ -645,14 +645,7 @@
             { x: 50 },
             "mousedown",
             {
-              // XXX Bug 1721287: For some reason we fire 2 selectchange events
-              // on the body when switching from the <input> to the <textarea>.
-              selectionchangeOnDocument:
-                document.activeElement != textControl &&
-                  (document.activeElement.tagName.toLocaleLowerCase() == "input" ||
-                   document.activeElement.tagName.toLocaleLowerCase() == "textarea")
-                  ? 2
-                  : 1,
+              selectionchangeOnDocument: 1,
             }
           );
 

editor/libeditor/tests/test_resizers_appearance.html

@@ -12,8 +12,8 @@
 
 </div>
 
-<div id="editor" contenteditable></div>
-<div id="clickaway" style="width: 3px; height: 3px;"></div>
+<div id="editor" contenteditable></div><br>
+<div id="clickaway" style="width: 30px; height: 30px; border: 3px solid red;"></div>
 <img src="green.png"><!-- for ensuring to load the image at first test of <img> case -->
 <pre id="test">
 

testing/web-platform/meta/selection/onselectionchange-on-distinct-text-controls.html.ini

@@ -1,6 +0,0 @@
-[onselectionchange-on-distinct-text-controls.html]
-  [selectionchange event on each input element fires independently]
-    expected: FAIL
-
-  [selectionchange event on each textarea element fires independently]
-    expected: FAIL

testing/web-platform/meta/selection/onselectionchange-on-document.html.ini

@@ -1,6 +0,0 @@
-[onselectionchange-on-document.html]
-  [task to fire selectionchange event gets queued each time selection is mutated]
-    expected: FAIL
-
-  [has scheduled selectionchange event is set to false at the beginning of a task to fire selectionchange event]
-    expected: FAIL

testing/web-platform/meta/selection/textcontrols/selectionchange.html.ini

@@ -1,26 +0,0 @@
-[selectionchange.html]
-  [Calling setRangeText() after select() on the input element]
-    expected:
-      if (os == "android") and not debug: [PASS, FAIL]
-      FAIL
-
-  [Calling setRangeText() repeatedly on the input element]
-    expected: FAIL
-
-  [Calling setRangeText() after select() on the disconnected input element]
-    expected: FAIL
-
-  [Calling setRangeText() repeatedly on the disconnected input element]
-    expected: FAIL
-
-  [Calling setRangeText() after select() on the textarea element]
-    expected: FAIL
-
-  [Calling setRangeText() repeatedly on the textarea element]
-    expected: FAIL
-
-  [Calling setRangeText() after select() on the disconnected textarea element]
-    expected: FAIL
-
-  [Calling setRangeText() repeatedly on the disconnected textarea element]
-    expected: FAIL