Bug 1384606 - part 4: Make `nsIFrame::GetFrameFromDirection` allow to return content in different native anonymous subtree if the caller wants r=emilio

The a11y module wants to traverse frames in native anonymous subtrees.
Therefore, this patch adds new option for allowing it, makes
`nsIFrame::GetFrameFromDirection` check it before comparing native anonymous
subtree root nodes, and makes `HyperTextAccessible::FindOffset` use the
option.

Differential Revision: https://phabricator.services.mozilla.com/D172759

accessible/generic/HyperTextAccessible.cpp

@@ -534,7 +534,8 @@ uint32_t HyperTextAccessible::FindOffset(uint32_t aOffset,
   PeekOffsetStruct pos(
       aAmount, aDirection, innerContentOffset, nsPoint(0, 0),
       {PeekOffsetOption::JumpLines, PeekOffsetOption::IsKeyboardSelect,
-       PeekOffsetOption::PreserveSpaces},
+       PeekOffsetOption::PreserveSpaces,
+       PeekOffsetOption::AllowContentInDifferentNativeAnonymousSubtreeRoot},
       aWordMovementType);
   nsresult rv = frameAtOffset->PeekOffset(&pos);
 

accessible/mac/HyperTextAccessibleWrap.mm

@@ -730,7 +730,8 @@ TextPoint HyperTextAccessibleWrap::FindTextPoint(
   PeekOffsetStruct pos(
       aAmount, aDirection, innerContentOffset, nsPoint(0, 0),
       {PeekOffsetOption::JumpLines, PeekOffsetOption::IsKeyboardSelect,
-       PeekOffsetOption::PreserveSpaces},
+       PeekOffsetOption::PreserveSpaces,
+       PeekOffsetOption::AllowContentInDifferentNativeAnonymousSubtreeRoot},
       aWordMovementType);
   nsresult rv = frameAtOffset->PeekOffset(&pos);
 

layout/generic/nsFrameSelection.cpp

@@ -977,10 +977,12 @@ nsPrevNextBidiLevels nsFrameSelection::GetPrevNextBidiLevels(
     return levels;
   }
 
+  PeekOffsetOptions peekOffsetOptions{PeekOffsetOption::ScrollViewStop};
+  if (aJumpLines) {
+    peekOffsetOptions += PeekOffsetOption::JumpLines;
+  }
   nsIFrame* newFrame =
-      currentFrame
-          ->GetFrameFromDirection(direction, false, aJumpLines, true, false)
-          .mFrame;
+      currentFrame->GetFrameFromDirection(direction, peekOffsetOptions).mFrame;
 
   FrameBidiData currentBidi = currentFrame->GetBidiData();
   mozilla::intl::BidiEmbeddingLevel currentLevel = currentBidi.embeddingLevel;

layout/generic/nsFrameSelection.h

@@ -101,6 +101,10 @@ enum class PeekOffsetOption : uint8_t {
   // If true, the offset has to end up in an editable node, otherwise we'll keep
   // searching.
   ForceEditableRegion,
+
+  // If set, the result's native anonymous subtree root may be different from
+  // the scan start content's root.
+  AllowContentInDifferentNativeAnonymousSubtreeRoot,
 };
 
 using PeekOffsetOptions = EnumSet<PeekOffsetOption>;

layout/generic/nsIFrame.cpp

@@ -9523,19 +9523,19 @@ Result<bool, nsresult> nsIFrame::IsLogicallyAtLineEdge(
 }
 
 nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
-    nsDirection aDirection, bool aVisual, bool aJumpLines, bool aScrollViewStop,
-    bool aForceEditableRegion) {
+    nsDirection aDirection, const PeekOffsetOptions& aOptions) {
   SelectablePeekReport result;
 
   nsPresContext* presContext = PresContext();
-  bool needsVisualTraversal = aVisual && presContext->BidiEnabled();
+  const bool needsVisualTraversal =
+      aOptions.contains(PeekOffsetOption::Visual) && presContext->BidiEnabled();
   nsCOMPtr<nsIFrameEnumerator> frameTraversal;
-  MOZ_TRY(NS_NewFrameTraversal(getter_AddRefs(frameTraversal), presContext,
-                               this, eLeaf, needsVisualTraversal,
-                               aScrollViewStop,
-                               true,  // aFollowOOFs
-                               false  // aSkipPopupChecks
-                               ));
+  MOZ_TRY(NS_NewFrameTraversal(
+      getter_AddRefs(frameTraversal), presContext, this, eLeaf,
+      needsVisualTraversal, aOptions.contains(PeekOffsetOption::ScrollViewStop),
+      true,  // aFollowOOFs
+      false  // aSkipPopupChecks
+      ));
 
   // Find the prev/next selectable frame
   bool selectable = false;
@@ -9544,8 +9544,8 @@ nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
   const nsIContent* const nativeAnonymousSubtreeContent =
       GetClosestNativeAnonymousSubtreeRoot();
   while (!selectable) {
-    auto [blockFrame, lineFrame] =
-        traversedFrame->GetContainingBlockForLine(aScrollViewStop);
+    auto [blockFrame, lineFrame] = traversedFrame->GetContainingBlockForLine(
+        aOptions.contains(PeekOffsetOption::ScrollViewStop));
     if (!blockFrame) {
       return result;
     }
@@ -9564,7 +9564,7 @@ nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
             : traversedFrame->IsLogicallyAtLineEdge(it, thisLine, aDirection));
     if (atLineEdge) {
       result.mJumpedLine = true;
-      if (!aJumpLines) {
+      if (!aOptions.contains(PeekOffsetOption::JumpLines)) {
         return result;  // we are done. cannot jump lines
       }
       int32_t lineToCheckWrap =
@@ -9580,19 +9580,24 @@ nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
       return result;
     }
 
-    auto IsSelectable = [aForceEditableRegion, nativeAnonymousSubtreeContent](
-                            const nsIFrame* aFrame) {
-      if (!aFrame->IsSelectable(nullptr)) {
-        return false;
-      }
-      // If the new frame is in a native anonymous subtree, we should treat it
-      // as not selectable unless the frame and found frame are in same subtree.
-      if (aFrame->GetClosestNativeAnonymousSubtreeRoot() !=
-          nativeAnonymousSubtreeContent) {
-        return false;
-      }
-      return !aForceEditableRegion || aFrame->GetContent()->IsEditable();
-    };
+    auto IsSelectable =
+        [aOptions, nativeAnonymousSubtreeContent](const nsIFrame* aFrame) {
+          if (!aFrame->IsSelectable(nullptr)) {
+            return false;
+          }
+          // If the new frame is in a native anonymous subtree, we should treat
+          // it as not selectable unless the frame and found frame are in same
+          // subtree.
+          if (!aOptions.contains(
+                  PeekOffsetOption::
+                      AllowContentInDifferentNativeAnonymousSubtreeRoot) &&
+              aFrame->GetClosestNativeAnonymousSubtreeRoot() !=
+                  nativeAnonymousSubtreeContent) {
+            return false;
+          }
+          return !aOptions.contains(PeekOffsetOption::ForceEditableRegion) ||
+                 aFrame->GetContent()->IsEditable();
+        };
 
     // Skip br frames, but only if we can select something before hitting the
     // end of the line or a non-selectable region.
@@ -9623,7 +9628,8 @@ nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
 
   result.mOffset = (aDirection == eDirNext) ? 0 : -1;
 
-  if (aVisual && nsBidiPresUtils::IsReversedDirectionFrame(traversedFrame)) {
+  if (aOptions.contains(PeekOffsetOption::Visual) &&
+      nsBidiPresUtils::IsReversedDirectionFrame(traversedFrame)) {
     // The new frame is reverse-direction, go to the other end
     result.mOffset = -1 - result.mOffset;
   }
@@ -9633,11 +9639,7 @@ nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
 
 nsIFrame::SelectablePeekReport nsIFrame::GetFrameFromDirection(
     const PeekOffsetStruct& aPos) {
-  return GetFrameFromDirection(
-      aPos.mDirection, aPos.mOptions.contains(PeekOffsetOption::Visual),
-      aPos.mOptions.contains(PeekOffsetOption::JumpLines),
-      aPos.mOptions.contains(PeekOffsetOption::ScrollViewStop),
-      aPos.mOptions.contains(PeekOffsetOption::ForceEditableRegion));
+  return GetFrameFromDirection(aPos.mDirection, aPos.mOptions);
 }
 
 nsView* nsIFrame::GetClosestView(nsPoint* aOffset) const {

layout/generic/nsIFrame.h

@@ -55,6 +55,7 @@
 #include "mozilla/AspectRatio.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/Baseline.h"
+#include "mozilla/EnumSet.h"
 #include "mozilla/EventForwards.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/RelativeTo.h"
@@ -129,6 +130,7 @@ struct CharacterDataChangeInfo;
 
 namespace mozilla {
 
+enum class PeekOffsetOption : uint8_t;
 enum class PseudoStyleType : uint8_t;
 enum class TableSelectionMode : uint32_t;
 
@@ -3877,17 +3879,14 @@ class nsIFrame : public nsQueryFrame {
    * Called to find the previous/next non-anonymous selectable leaf frame.
    *
    * @param aDirection the direction to move in (eDirPrevious or eDirNext)
-   * @param aVisual whether bidi caret behavior is visual (true) or logical
-   * (false)
-   * @param aJumpLines whether to allow jumping across line boundaries
-   * @param aScrollViewStop whether to stop when reaching a scroll frame
-   * boundary
+   * @param aOptions the other options which is same as
+   * PeekOffsetStruct::mOptions.
+   * FIXME: Due to the include hell, we cannot use the alias, PeekOffsetOptions
+   * is not available in this header file.
    */
-  SelectablePeekReport GetFrameFromDirection(nsDirection aDirection,
-                                             bool aVisual, bool aJumpLines,
-                                             bool aScrollViewStop,
-                                             bool aForceEditableRegion);
-
+  SelectablePeekReport GetFrameFromDirection(
+      nsDirection aDirection,
+      const mozilla::EnumSet<mozilla::PeekOffsetOption>& aOptions);
   SelectablePeekReport GetFrameFromDirection(
       const mozilla::PeekOffsetStruct& aPos);