Bug 1816536 - Fix document edge issues in FindBounary. r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D169726

accessible/base/TextLeafRange.cpp

@@ -602,6 +602,15 @@ bool TextLeafPoint::operator<=(const TextLeafPoint& aPoint) const {
   return *this == aPoint || *this < aPoint;
 }
 
+bool TextLeafPoint::IsDocEdge(nsDirection aDirection) const {
+  if (aDirection == eDirPrevious) {
+    return mOffset == 0 && !PrevLeaf(mAcc);
+  }
+
+  return mOffset == static_cast<int32_t>(nsAccUtils::TextLength(mAcc)) &&
+         !NextLeaf(mAcc);
+}
+
 bool TextLeafPoint::IsEmptyLastLine() const {
   if (mAcc->IsHTMLBr() && mOffset == 1) {
     return true;
@@ -1103,10 +1112,10 @@ TextLeafPoint TextLeafPoint::FindWordEnd(nsDirection aDirection,
       return *this;  // Can't go any further.
     }
     prevIsSpace = prev.IsSpace();
-    if ((aFlags & BoundaryFlags::eIncludeOrigin) && origIsSpace &&
-        !prevIsSpace) {
-      // The origin is space, but the previous character is not. This means
-      // we're at the end of a word.
+    if ((aFlags & BoundaryFlags::eIncludeOrigin) &&
+        (origIsSpace || IsDocEdge(eDirNext)) && !prevIsSpace) {
+      // The origin is space or end of document, but the previous
+      // character is not. This means we're at the end of a word.
       return *this;
     }
   }
@@ -1129,8 +1138,15 @@ TextLeafPoint TextLeafPoint::FindWordEnd(nsDirection aDirection,
     }
   }
   if (aDirection == eDirNext) {
+    BoundaryFlags flags = aFlags;
+    if (IsDocEdge(eDirPrevious)) {
+      // If this is the start of the doc don't be inclusive in the word-start
+      // search because there is no preceding block where this could be a
+      // word-end for.
+      flags &= ~BoundaryFlags::eIncludeOrigin;
+    }
     boundary = boundary.FindBoundary(nsIAccessibleText::BOUNDARY_WORD_START,
-                                     eDirNext, aFlags);
+                                     eDirNext, flags);
   }
   // At this point, boundary is either the start of a word or at a space. A
   // word ends at the beginning of consecutive space. Therefore, skip back to
@@ -1152,6 +1168,11 @@ TextLeafPoint TextLeafPoint::FindWordEnd(nsDirection aDirection,
 
 TextLeafPoint TextLeafPoint::FindParagraphSameAcc(nsDirection aDirection,
                                                   bool aIncludeOrigin) const {
+  if (aIncludeOrigin && IsDocEdge(eDirPrevious)) {
+    // The top of the document is a paragraph boundary.
+    return *this;
+  }
+
   if (mAcc->IsTextLeaf() &&
       // We don't want to copy strings unnecessarily. See below for the context
       // of these individual conditions.

accessible/base/TextLeafRange.h

@@ -194,6 +194,8 @@ class TextLeafPoint final {
  private:
   bool IsEmptyLastLine() const;
 
+  bool IsDocEdge(nsDirection aDirection) const;
+
   char16_t GetChar() const;
 
   TextLeafPoint FindLineStartSameRemoteAcc(nsDirection aDirection,

accessible/tests/browser/textleafrange/browser_textleafpoint.js

@@ -117,11 +117,7 @@ the <strong>big</strong> rug.</p>
       BOUNDARY_WORD_END,
       DIRECTION_NEXT,
       expectedWordEndSequence,
-      "Forward BOUNDARY_WORD_END sequence is correct",
-      {
-        // XXX: Includes first point in doc which is not a word end
-        todo: true,
-      }
+      "Forward BOUNDARY_WORD_END sequence is correct"
     );
 
     testBoundarySequence(
@@ -129,11 +125,7 @@ the <strong>big</strong> rug.</p>
       BOUNDARY_WORD_END,
       DIRECTION_PREVIOUS,
       [readablePoint(firstPoint), ...expectedWordEndSequence].reverse(),
-      "Backward BOUNDARY_WORD_END sequence is correct",
-      {
-        // XXX: Doesn't include last point in doc which is a word end
-        todo: true,
-      }
+      "Backward BOUNDARY_WORD_END sequence is correct"
     );
 
     const expectedLineStartSequence = [
@@ -265,9 +257,8 @@ on a <span style="display: block;">rug</span></p>
     <li>Three</li>
   </ul>`,
   function(browser, docAcc) {
-    const container = findAccessibleChildByID(docAcc, "p");
-    const firstPoint = createTextLeafPoint(container, 0);
-    const lastPoint = createTextLeafPoint(container, kTextEndOffset);
+    const firstPoint = createTextLeafPoint(docAcc, 0);
+    const lastPoint = createTextLeafPoint(docAcc, kTextEndOffset);
 
     const expectedParagraphStart = [
       ["A bug\non a ", 0],
@@ -283,11 +274,22 @@ on a <span style="display: block;">rug</span></p>
       BOUNDARY_PARAGRAPH,
       DIRECTION_NEXT,
       [...expectedParagraphStart, readablePoint(lastPoint)],
-      "Forward BOUNDARY_PARAGRAPH sequence is correct",
-      {
-        // XXX: Missing the first paragraph start.
-        todo: true,
-      }
+      "Forward BOUNDARY_PARAGRAPH sequence is correct"
+    );
+
+    const paragraphStart = createTextLeafPoint(
+      findAccessibleChildByID(docAcc, "p2").firstChild,
+      0
+    );
+    const wordEnd = paragraphStart.findBoundary(
+      BOUNDARY_WORD_END,
+      DIRECTION_NEXT,
+      BOUNDARY_FLAG_INCLUDE_ORIGIN
+    );
+    testPointEqual(
+      wordEnd,
+      paragraphStart,
+      "The word end from the previous block is the first point in this block"
     );
   },
   { chrome: true, topLevel: isCacheEnabled, iframe: false, remoteIframe: false }