Bug 1367683 - Optimize initializing nsRange

Tag #1375

16 files changed, 330 insertions, 205 deletions

diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index d0e861b1a7..e16c1831cb 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -6468,7 +6468,7 @@ already_AddRefed<nsRange>
 nsIDocument::CreateRange(ErrorResult& rv)
 {
   RefPtr<nsRange> range = new nsRange(this);
-  nsresult res = range->Set(this, 0, this, 0);
+  nsresult res = range->CollapseTo(this, 0);
   if (NS_FAILED(res)) {
     rv.Throw(res);
     return nullptr;
diff --git a/dom/base/nsRange.cpp b/dom/base/nsRange.cpp
index d45a2c9750..154b3428f2 100644
--- a/dom/base/nsRange.cpp
+++ b/dom/base/nsRange.cpp
@@ -270,14 +270,17 @@ nsRange::CreateRange(nsINode* aStartParent, int32_t aStartOffset,
                      nsINode* aEndParent, int32_t aEndOffset,
                      nsRange** aRange)
 {
-  nsCOMPtr<nsIDOMNode> startDomNode = do_QueryInterface(aStartParent);
-  nsCOMPtr<nsIDOMNode> endDomNode = do_QueryInterface(aEndParent);
-
-  nsresult rv = CreateRange(startDomNode, aStartOffset, endDomNode, aEndOffset,
-                            aRange);
-
-  return rv;
+  MOZ_ASSERT(aRange);
+  *aRange = nullptr;
 
+  RefPtr<nsRange> range = new nsRange(aStartParent);
+  nsresult rv = range->SetStartAndEnd(aStartParent, aStartOffset,
+                                      aEndParent, aEndOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  range.forget(aRange);
+  return NS_OK;
 }
 
 /* static */
@@ -286,22 +289,9 @@ nsRange::CreateRange(nsIDOMNode* aStartParent, int32_t aStartOffset,
                      nsIDOMNode* aEndParent, int32_t aEndOffset,
                      nsRange** aRange)
 {
-  MOZ_ASSERT(aRange);
-  *aRange = nullptr;
-
   nsCOMPtr<nsINode> startParent = do_QueryInterface(aStartParent);
-  NS_ENSURE_ARG_POINTER(startParent);
-
-  RefPtr<nsRange> range = new nsRange(startParent);
-
-  nsresult rv = range->SetStart(startParent, aStartOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  rv = range->SetEnd(aEndParent, aEndOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  range.forget(aRange);
-  return NS_OK;
+  nsCOMPtr<nsINode> endParent = do_QueryInterface(aEndParent);
+  return CreateRange(startParent, aStartOffset, endParent, aEndOffset, aRange);
 }
 
 /* static */
@@ -1137,6 +1127,15 @@ nsRange::GetCommonAncestorContainer(nsIDOMNode** aCommonParent)
   return rv.StealNSResult();
 }
 
+/* static */
+bool
+nsRange::IsValidOffset(nsINode* aNode, int32_t aOffset)
+{
+  return aNode &&
+         aOffset >= 0 &&
+         static_cast<size_t>(aOffset) <= aNode->Length();
+}
+
 nsINode*
 nsRange::IsValidBoundary(nsINode* aNode)
 {
@@ -1217,7 +1216,7 @@ nsRange::SetStart(nsINode* aParent, int32_t aOffset)
     return NS_ERROR_DOM_INVALID_NODE_TYPE_ERR;
   }
 
-  if (aOffset < 0 || uint32_t(aOffset) > aParent->Length()) {
+  if (!IsValidOffset(aParent, aOffset)) {
     return NS_ERROR_DOM_INDEX_SIZE_ERR;
   }
 
@@ -1246,7 +1245,9 @@ nsRange::SetStartBefore(nsINode& aNode, ErrorResult& aRv)
   }
 
   AutoInvalidateSelection atEndOfBlock(this);
-  aRv = SetStart(aNode.GetParentNode(), IndexOf(&aNode));
+  int32_t offset = -1;
+  nsINode* parent = GetParentAndOffsetBefore(&aNode, &offset);
+  aRv = SetStart(parent, offset);
 }
 
 NS_IMETHODIMP
@@ -1272,7 +1273,9 @@ nsRange::SetStartAfter(nsINode& aNode, ErrorResult& aRv)
   }
 
   AutoInvalidateSelection atEndOfBlock(this);
-  aRv = SetStart(aNode.GetParentNode(), IndexOf(&aNode) + 1);
+  int32_t offset = -1;
+  nsINode* parent = GetParentAndOffsetAfter(&aNode, &offset);
+  aRv = SetStart(parent, offset);
 }
 
 NS_IMETHODIMP
@@ -1321,7 +1324,7 @@ nsRange::SetEnd(nsINode* aParent, int32_t aOffset)
     return NS_ERROR_DOM_INVALID_NODE_TYPE_ERR;
   }
 
-  if (aOffset < 0 || uint32_t(aOffset) > aParent->Length()) {
+  if (!IsValidOffset(aParent, aOffset)) {
     return NS_ERROR_DOM_INDEX_SIZE_ERR;
   }
 
@@ -1340,6 +1343,64 @@ nsRange::SetEnd(nsINode* aParent, int32_t aOffset)
   return NS_OK;
 }
 
+nsresult
+nsRange::SetStartAndEnd(nsINode* aStartParent, int32_t aStartOffset,
+                        nsINode* aEndParent, int32_t aEndOffset)
+{
+  if (NS_WARN_IF(!aStartParent) || NS_WARN_IF(!aEndParent)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsINode* newStartRoot = IsValidBoundary(aStartParent);
+  if (!newStartRoot) {
+    return NS_ERROR_DOM_INVALID_NODE_TYPE_ERR;
+  }
+  if (!IsValidOffset(aStartParent, aStartOffset)) {
+    return NS_ERROR_DOM_INDEX_SIZE_ERR;
+  }
+
+  if (aStartParent == aEndParent) {
+    if (!IsValidOffset(aEndParent, aEndOffset)) {
+      return NS_ERROR_DOM_INDEX_SIZE_ERR;
+    }
+    // If the end offset is less than the start offset, this should be
+    // collapsed at the end offset.
+    if (aStartOffset > aEndOffset) {
+      DoSetRange(aEndParent, aEndOffset, aEndParent, aEndOffset, newStartRoot);
+    } else {
+      DoSetRange(aStartParent, aStartOffset,
+                 aEndParent, aEndOffset, newStartRoot);
+    }
+    return NS_OK;
+  }
+
+  nsINode* newEndRoot = IsValidBoundary(aEndParent);
+  if (!newEndRoot) {
+    return NS_ERROR_DOM_INVALID_NODE_TYPE_ERR;
+  }
+  if (!IsValidOffset(aEndParent, aEndOffset)) {
+    return NS_ERROR_DOM_INDEX_SIZE_ERR;
+  }
+
+  // If they have different root, this should be collapsed at the end point.
+  if (newStartRoot != newEndRoot) {
+    DoSetRange(aEndParent, aEndOffset, aEndParent, aEndOffset, newEndRoot);
+    return NS_OK;
+  }
+
+  // If the end point is before the start point, this should be collapsed at
+  // the end point.
+  if (nsContentUtils::ComparePoints(aStartParent, aStartOffset,
+                                    aEndParent, aEndOffset) == 1) {
+    DoSetRange(aEndParent, aEndOffset, aEndParent, aEndOffset, newEndRoot);
+    return NS_OK;
+  }
+
+  // Otherwise, set the range as specified.
+  DoSetRange(aStartParent, aStartOffset, aEndParent, aEndOffset, newStartRoot);
+  return NS_OK;
+}
+
 void
 nsRange::SetEndBefore(nsINode& aNode, ErrorResult& aRv)
 {
@@ -1350,7 +1411,9 @@ nsRange::SetEndBefore(nsINode& aNode, ErrorResult& aRv)
   }
 
   AutoInvalidateSelection atEndOfBlock(this);
-  aRv = SetEnd(aNode.GetParentNode(), IndexOf(&aNode));
+  int32_t offset = -1;
+  nsINode* parent = GetParentAndOffsetBefore(&aNode, &offset);
+  aRv = SetEnd(parent, offset);
 }
 
 NS_IMETHODIMP
@@ -1376,7 +1439,9 @@ nsRange::SetEndAfter(nsINode& aNode, ErrorResult& aRv)
   }
 
   AutoInvalidateSelection atEndOfBlock(this);
-  aRv = SetEnd(aNode.GetParentNode(), IndexOf(&aNode) + 1);
+  int32_t offset = -1;
+  nsINode* parent = GetParentAndOffsetAfter(&aNode, &offset);
+  aRv = SetEnd(parent, offset);
 }
 
 NS_IMETHODIMP
diff --git a/dom/base/nsRange.h b/dom/base/nsRange.h
index 4b35c749ab..70911338de 100644
--- a/dom/base/nsRange.h
+++ b/dom/base/nsRange.h
@@ -148,19 +148,61 @@ public:
 
   nsINode* GetCommonAncestor() const;
   void Reset();
+
+  /**
+   * SetStart() and SetEnd() sets start point or end point separately.
+   * However, this is expensive especially when it's a range of Selection.
+   * When you set both start and end of a range, you should use
+   * SetStartAndEnd() instead.
+   */
   nsresult SetStart(nsINode* aParent, int32_t aOffset);
   nsresult SetEnd(nsINode* aParent, int32_t aOffset);
+
   already_AddRefed<nsRange> CloneRange() const;
 
-  nsresult Set(nsINode* aStartParent, int32_t aStartOffset,
-               nsINode* aEndParent, int32_t aEndOffset)
+  /**
+   * SetStartAndEnd() works similar to call both SetStart() and SetEnd().
+   * Different from calls them separately, this does nothing if either
+   * the start point or the end point is invalid point.
+   * If the specified start point is after the end point, the range will be
+   * collapsed at the end point.  Similarly, if they are in different root,
+   * the range will be collapsed at the end point.
+   */
+  nsresult SetStartAndEnd(nsINode* aStartParent, int32_t aStartOffset,
+                          nsINode* aEndParent, int32_t aEndOffset);
+
+  /**
+   * CollapseTo() works similar to call both SetStart() and SetEnd() with
+   * same node and offset.  This just calls SetStartAndParent() to set
+   * collapsed range at aParent and aOffset.
+   */
+  nsresult CollapseTo(nsINode* aParent, int32_t aOffset)
   {
-    // If this starts being hot, we may be able to optimize this a bit,
-    // but for now just set start and end separately.
-    nsresult rv = SetStart(aStartParent, aStartOffset);
-    NS_ENSURE_SUCCESS(rv, rv);
+    return SetStartAndEnd(aParent, aOffset, aParent, aOffset);
+  }
 
-    return SetEnd(aEndParent, aEndOffset);
+  /**
+   * Retrieves node and offset for setting start or end of a range to
+   * before or after aNode.
+   */
+  static nsINode* GetParentAndOffsetAfter(nsINode* aNode, int32_t* aOffset)
+  {
+    MOZ_ASSERT(aNode);
+    MOZ_ASSERT(aOffset);
+    nsINode* parentNode = aNode->GetParentNode();
+    *aOffset = parentNode ? parentNode->IndexOf(aNode) : -1;
+    if (*aOffset >= 0) {
+      (*aOffset)++;
+    }
+    return parentNode;
+  }
+  static nsINode* GetParentAndOffsetBefore(nsINode* aNode, int32_t* aOffset)
+  {
+    MOZ_ASSERT(aNode);
+    MOZ_ASSERT(aOffset);
+    nsINode* parentNode = aNode->GetParentNode();
+    *aOffset = parentNode ? parentNode->IndexOf(aNode) : -1;
+    return parentNode;
   }
 
   NS_IMETHOD GetUsedFontFaces(nsIDOMFontFaceList** aResult);
@@ -296,6 +338,7 @@ protected:
   void RegisterCommonAncestor(nsINode* aNode);
   void UnregisterCommonAncestor(nsINode* aNode);
   nsINode* IsValidBoundary(nsINode* aNode);
+  static bool IsValidOffset(nsINode* aNode, int32_t aOffset);
 
   // CharacterDataChanged set aNotInsertedYet to true to disable an assertion
   // and suppress re-registering a range common ancestor node since
diff --git a/dom/events/ContentEventHandler.cpp b/dom/events/ContentEventHandler.cpp
index 935ade23f4..df54a4d44a 100644
--- a/dom/events/ContentEventHandler.cpp
+++ b/dom/events/ContentEventHandler.cpp
@@ -980,11 +980,7 @@ ContentEventHandler::SetRangeFromFlatTextOffset(nsRange* aRange,
 
   // Special case like <br contenteditable>
   if (!mRootContent->HasChildren()) {
-    nsresult rv = aRange->SetStart(mRootContent, 0);
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      return rv;
-    }
-    rv = aRange->SetEnd(mRootContent, 0);
+    nsresult rv = aRange->CollapseTo(mRootContent, 0);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
@@ -2880,8 +2876,7 @@ ContentEventHandler::AdjustCollapsedRangeMaybeIntoTextNode(nsRange* aRange)
     return NS_OK;
   }
 
-  nsresult rv = aRange->Set(childNode, offsetInChildNode,
-                            childNode, offsetInChildNode);
+  nsresult rv = aRange->CollapseTo(childNode, offsetInChildNode);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
diff --git a/editor/libeditor/HTMLEditRules.cpp b/editor/libeditor/HTMLEditRules.cpp
index fcbb75ee6f..0aa2bde8c1 100644
--- a/editor/libeditor/HTMLEditRules.cpp
+++ b/editor/libeditor/HTMLEditRules.cpp
@@ -1422,16 +1422,15 @@ HTMLEditRules::WillInsertText(EditAction aAction,
     if (!mDocChangeRange) {
       mDocChangeRange = new nsRange(selNode);
     }
-    rv = mDocChangeRange->SetStart(selNode, selOffset);
-    NS_ENSURE_SUCCESS(rv, rv);
 
     if (curNode) {
-      rv = mDocChangeRange->SetEnd(curNode, curOffset);
+      rv = mDocChangeRange->SetStartAndEnd(selNode, selOffset,
+                                           curNode, curOffset);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
     } else {
-      rv = mDocChangeRange->SetEnd(selNode, selOffset);
+      rv = mDocChangeRange->CollapseTo(selNode, selOffset);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
@@ -5093,10 +5092,11 @@ HTMLEditRules::ExpandSelectionForDeletion(Selection& aSelection)
 
     // Create a range that represents expanded selection
     RefPtr<nsRange> range = new nsRange(selStartNode);
-    nsresult rv = range->SetStart(selStartNode, selStartOffset);
-    NS_ENSURE_SUCCESS(rv, rv);
-    rv = range->SetEnd(selEndNode, selEndOffset);
-    NS_ENSURE_SUCCESS(rv, rv);
+    nsresult rv = range->SetStartAndEnd(selStartNode, selStartOffset,
+                                        selEndNode, selEndOffset);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
 
     // Check if block is entirely inside range
     if (brBlock) {
@@ -5558,26 +5558,27 @@ HTMLEditRules::PromoteRange(nsRange& aRange,
   // This is tricky.  The basic idea is to push out the range endpoints to
   // truly enclose the blocks that we will affect.
 
-  nsCOMPtr<nsIDOMNode> opStartNode;
-  nsCOMPtr<nsIDOMNode> opEndNode;
+  nsCOMPtr<nsIDOMNode> opDOMStartNode;
+  nsCOMPtr<nsIDOMNode> opDOMEndNode;
   int32_t opStartOffset, opEndOffset;
 
   GetPromotedPoint(kStart, GetAsDOMNode(startNode), startOffset,
-                   aOperationType, address_of(opStartNode), &opStartOffset);
+                   aOperationType, address_of(opDOMStartNode), &opStartOffset);
   GetPromotedPoint(kEnd, GetAsDOMNode(endNode), endOffset, aOperationType,
-                   address_of(opEndNode), &opEndOffset);
+                   address_of(opDOMEndNode), &opEndOffset);
 
   // Make sure that the new range ends up to be in the editable section.
   if (!htmlEditor->IsDescendantOfEditorRoot(
-        EditorBase::GetNodeAtRangeOffsetPoint(opStartNode, opStartOffset)) ||
+        EditorBase::GetNodeAtRangeOffsetPoint(opDOMStartNode, opStartOffset)) ||
       !htmlEditor->IsDescendantOfEditorRoot(
-        EditorBase::GetNodeAtRangeOffsetPoint(opEndNode, opEndOffset - 1))) {
+        EditorBase::GetNodeAtRangeOffsetPoint(opDOMEndNode, opEndOffset - 1))) {
     return;
   }
 
-  DebugOnly<nsresult> rv = aRange.SetStart(opStartNode, opStartOffset);
-  MOZ_ASSERT(NS_SUCCEEDED(rv));
-  rv = aRange.SetEnd(opEndNode, opEndOffset);
+  nsCOMPtr<nsINode> opStartNode = do_QueryInterface(opDOMStartNode);
+  nsCOMPtr<nsINode> opEndNode = do_QueryInterface(opDOMEndNode);
+  DebugOnly<nsresult> rv =
+    aRange.SetStartAndEnd(opStartNode, opStartOffset, opEndNode, opEndOffset);
   MOZ_ASSERT(NS_SUCCEEDED(rv));
 }
 
@@ -7196,10 +7197,10 @@ HTMLEditRules::PinSelectionToNewBlock(Selection* aSelection)
   nsCOMPtr<nsINode> node = do_QueryInterface(selNode);
   NS_ENSURE_STATE(node);
   RefPtr<nsRange> range = new nsRange(node);
-  rv = range->SetStart(selNode, selOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = range->SetEnd(selNode, selOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  rv = range->CollapseTo(node, selOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   bool nodeBefore, nodeAfter;
   rv = nsRange::CompareNodeToRange(mNewBlock, range, &nodeBefore, &nodeAfter);
   NS_ENSURE_SUCCESS(rv, rv);
@@ -8095,10 +8096,13 @@ HTMLEditRules::DidSplitNode(nsIDOMNode* aExistingRightNode,
   if (!mListenerEnabled) {
     return NS_OK;
   }
-  nsresult rv = mUtilRange->SetStart(aNewLeftNode, 0);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = mUtilRange->SetEnd(aExistingRightNode, 0);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> newLeftNode = do_QueryInterface(aNewLeftNode);
+  nsCOMPtr<nsINode> existingRightNode = do_QueryInterface(aExistingRightNode);
+  nsresult rv = mUtilRange->SetStartAndEnd(newLeftNode, 0,
+                                           existingRightNode, 0);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   return UpdateDocChangeRange(mUtilRange);
 }
 
@@ -8123,11 +8127,12 @@ HTMLEditRules::DidJoinNodes(nsIDOMNode* aLeftNode,
   if (!mListenerEnabled) {
     return NS_OK;
   }
+  nsCOMPtr<nsINode> rightNode = do_QueryInterface(aRightNode);
   // assumption that Join keeps the righthand node
-  nsresult rv = mUtilRange->SetStart(aRightNode, mJoinOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = mUtilRange->SetEnd(aRightNode, mJoinOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsresult rv = mUtilRange->CollapseTo(rightNode, mJoinOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   return UpdateDocChangeRange(mUtilRange);
 }
 
@@ -8149,11 +8154,12 @@ HTMLEditRules::DidInsertText(nsIDOMCharacterData* aTextNode,
     return NS_OK;
   }
   int32_t length = aString.Length();
-  nsCOMPtr<nsIDOMNode> theNode = do_QueryInterface(aTextNode);
-  nsresult rv = mUtilRange->SetStart(theNode, aOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = mUtilRange->SetEnd(theNode, aOffset+length);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> theNode = do_QueryInterface(aTextNode);
+  nsresult rv = mUtilRange->SetStartAndEnd(theNode, aOffset,
+                                           theNode, aOffset + length);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   return UpdateDocChangeRange(mUtilRange);
 }
 
@@ -8174,11 +8180,11 @@ HTMLEditRules::DidDeleteText(nsIDOMCharacterData* aTextNode,
   if (!mListenerEnabled) {
     return NS_OK;
   }
-  nsCOMPtr<nsIDOMNode> theNode = do_QueryInterface(aTextNode);
-  nsresult rv = mUtilRange->SetStart(theNode, aOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = mUtilRange->SetEnd(theNode, aOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> theNode = do_QueryInterface(aTextNode);
+  nsresult rv = mUtilRange->CollapseTo(theNode, aOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   return UpdateDocChangeRange(mUtilRange);
 }
 
@@ -8193,22 +8199,27 @@ HTMLEditRules::WillDeleteSelection(nsISelection* aSelection)
   }
   RefPtr<Selection> selection = aSelection->AsSelection();
   // get the (collapsed) selection location
-  nsCOMPtr<nsIDOMNode> selNode;
-  int32_t selOffset;
-
+  nsCOMPtr<nsINode> startNode;
+  int32_t startOffset;
   NS_ENSURE_STATE(mHTMLEditor);
   nsresult rv =
     mHTMLEditor->GetStartNodeAndOffset(selection,
-                                       getter_AddRefs(selNode), &selOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = mUtilRange->SetStart(selNode, selOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+                                      getter_AddRefs(startNode), &startOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  nsCOMPtr<nsINode> endNode;
+  int32_t endOffset;
   NS_ENSURE_STATE(mHTMLEditor);
   rv = mHTMLEditor->GetEndNodeAndOffset(selection,
-                                        getter_AddRefs(selNode), &selOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = mUtilRange->SetEnd(selNode, selOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+                                       getter_AddRefs(endNode), &endOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  rv = mUtilRange->SetStartAndEnd(startNode, startOffset, endNode, endOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   return UpdateDocChangeRange(mUtilRange);
 }
 
diff --git a/editor/libeditor/HTMLEditor.cpp b/editor/libeditor/HTMLEditor.cpp
index 532da7a150..73dd1673b2 100644
--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@@ -3284,8 +3284,8 @@ HTMLEditor::DoContentInserted(nsIDocument* aDocument,
           sibling = sibling->GetNextSibling();
         }
       }
-      nsresult rv = range->Set(aContainer, aIndexInContainer,
-                               aContainer, endIndex);
+      nsresult rv = range->SetStartAndEnd(aContainer, aIndexInContainer,
+                                          aContainer, endIndex);
       if (NS_SUCCEEDED(rv)) {
         mInlineSpellChecker->SpellCheckRange(range);
       }
diff --git a/editor/libeditor/HTMLStyleEditor.cpp b/editor/libeditor/HTMLStyleEditor.cpp
index 6a1ffe8b41..7141cfd61e 100644
--- a/editor/libeditor/HTMLStyleEditor.cpp
+++ b/editor/libeditor/HTMLStyleEditor.cpp
@@ -541,9 +541,11 @@ HTMLEditor::SplitStyleAboveRange(nsRange* inRange,
   NS_ENSURE_SUCCESS(rv, rv);
 
   // reset the range
-  rv = inRange->SetStart(startNode, startOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  return inRange->SetEnd(endNode, endOffset);
+  rv = inRange->SetStartAndEnd(startNode, startOffset, endNode, endOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  return NS_OK;
 }
 
 nsresult
@@ -885,10 +887,11 @@ HTMLEditor::PromoteRangeIfStartsOrEndsInNamedAnchor(nsRange& aRange)
     endOffset = endNode ? endNode->IndexOf(parent) + 1 : 0;
   }
 
-  nsresult rv = aRange.SetStart(startNode, startOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = aRange.SetEnd(endNode, endOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsresult rv = aRange.SetStartAndEnd(startNode, startOffset,
+                                      endNode, endOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
 
   return NS_OK;
 }
@@ -918,10 +921,11 @@ HTMLEditor::PromoteInlineRange(nsRange& aRange)
     endNode = parent;
   }
 
-  nsresult rv = aRange.SetStart(startNode, startOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = aRange.SetEnd(endNode, endOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsresult rv = aRange.SetStartAndEnd(startNode, startOffset,
+                                      endNode, endOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
 
   return NS_OK;
 }
diff --git a/editor/libeditor/SelectionState.cpp b/editor/libeditor/SelectionState.cpp
index f9ad5947a8..057e048758 100644
--- a/editor/libeditor/SelectionState.cpp
+++ b/editor/libeditor/SelectionState.cpp
@@ -686,7 +686,8 @@ already_AddRefed<nsRange>
 RangeItem::GetRange()
 {
   RefPtr<nsRange> range = new nsRange(startNode);
-  if (NS_FAILED(range->Set(startNode, startOffset, endNode, endOffset))) {
+  if (NS_FAILED(range->SetStartAndEnd(startNode, startOffset,
+                                      endNode, endOffset))) {
     return nullptr;
   }
   return range.forget();
diff --git a/editor/libeditor/WSRunObject.cpp b/editor/libeditor/WSRunObject.cpp
index 39ac3fee86..0748f09e53 100644
--- a/editor/libeditor/WSRunObject.cpp
+++ b/editor/libeditor/WSRunObject.cpp
@@ -1315,7 +1315,7 @@ WSRunObject::DeleteChars(nsINode* aStartNode,
       if (!range) {
         range = new nsRange(aStartNode);
         nsresult rv =
-          range->Set(aStartNode, aStartOffset, aEndNode, aEndOffset);
+          range->SetStartAndEnd(aStartNode, aStartOffset, aEndNode, aEndOffset);
         NS_ENSURE_SUCCESS(rv, rv);
       }
       bool nodeBefore, nodeAfter;
diff --git a/editor/txtsvc/nsTextServicesDocument.cpp b/editor/txtsvc/nsTextServicesDocument.cpp
index e0c779683b..ccf964d2cf 100644
--- a/editor/txtsvc/nsTextServicesDocument.cpp
+++ b/editor/txtsvc/nsTextServicesDocument.cpp
@@ -406,11 +406,13 @@ nsTextServicesDocument::ExpandRangeToWordBoundaries(nsIDOMRange *aRange)
 
   // Now adjust the range so that it uses our new
   // end points.
-
-  rv = range->SetEnd(rngEndNode, rngEndOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  return range->SetStart(rngStartNode, rngStartOffset);
+  nsCOMPtr<nsINode> startNode = do_QueryInterface(rngStartNode);
+  nsCOMPtr<nsINode> endNode = do_QueryInterface(rngEndNode);
+  rv = range->SetStartAndEnd(startNode, rngStartOffset, endNode, rngEndOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  return NS_OK;
 }
 
 NS_IMETHODIMP
diff --git a/extensions/spellcheck/src/mozInlineSpellChecker.cpp b/extensions/spellcheck/src/mozInlineSpellChecker.cpp
index 96011a37e3..118035aa57 100644
--- a/extensions/spellcheck/src/mozInlineSpellChecker.cpp
+++ b/extensions/spellcheck/src/mozInlineSpellChecker.cpp
@@ -164,16 +164,23 @@ mozInlineSpellStatus::InitForEditorChange(
   NS_ENSURE_SUCCESS(rv, rv);
   if (cmpResult < 0) {
     // previous anchor node is before the current anchor
-    rv = mRange->SetStart(aPreviousNode, aPreviousOffset);
-    NS_ENSURE_SUCCESS(rv, rv);
-    rv = mRange->SetEnd(aAnchorNode, aAnchorOffset);
+    nsCOMPtr<nsINode> previousNode = do_QueryInterface(aPreviousNode);
+    nsCOMPtr<nsINode> anchorNode = do_QueryInterface(aAnchorNode);
+    rv = mRange->SetStartAndEnd(previousNode, aPreviousOffset,
+                                anchorNode, aAnchorOffset);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
   } else {
     // previous anchor node is after (or the same as) the current anchor
-    rv = mRange->SetStart(aAnchorNode, aAnchorOffset);
-    NS_ENSURE_SUCCESS(rv, rv);
-    rv = mRange->SetEnd(aPreviousNode, aPreviousOffset);
+    nsCOMPtr<nsINode> previousNode = do_QueryInterface(aPreviousNode);
+    nsCOMPtr<nsINode> anchorNode = do_QueryInterface(aAnchorNode);
+    rv = mRange->SetStartAndEnd(anchorNode, aAnchorOffset,
+                                previousNode, aPreviousOffset);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
   }
-  NS_ENSURE_SUCCESS(rv, rv);
 
   // On insert save this range: DoSpellCheck optimizes things in this range.
   // Otherwise, just leave this nullptr.
@@ -454,17 +461,19 @@ mozInlineSpellStatus::GetDocument(nsIDOMDocument** aDocument)
 
 nsresult
 mozInlineSpellStatus::PositionToCollapsedRange(nsIDOMDocument* aDocument,
-    nsIDOMNode* aNode, int32_t aOffset, nsIDOMRange** aRange)
+                                               nsIDOMNode* aNode,
+                                               int32_t aOffset,
+                                               nsRange** aRange)
 {
   *aRange = nullptr;
-  nsCOMPtr<nsIDOMRange> range;
-  nsresult rv = aDocument->CreateRange(getter_AddRefs(range));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> documentNode = do_QueryInterface(aDocument);
+  RefPtr<nsRange> range = new nsRange(documentNode);
 
-  rv = range->SetStart(aNode, aOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  rv = range->SetEnd(aNode, aOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> node = do_QueryInterface(aNode);
+  nsresult rv = range->CollapseTo(node, aOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
 
   range.swap(*aRange);
   return NS_OK;
@@ -1164,9 +1173,8 @@ mozInlineSpellChecker::MakeSpellCheckRange(
   NS_ENSURE_SUCCESS(rv, rv);
   NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);
 
-  nsCOMPtr<nsIDOMRange> range;
-  rv = doc->CreateRange(getter_AddRefs(range));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> documentNode = do_QueryInterface(doc);
+  RefPtr<nsRange> range = new nsRange(documentNode);
 
   // possibly use full range of the editor
   nsCOMPtr<nsIDOMElement> rootElem;
@@ -1198,15 +1206,23 @@ mozInlineSpellChecker::MakeSpellCheckRange(
   if (aStartNode == aEndNode && aStartOffset == aEndOffset)
     return NS_OK;
 
-  rv = range->SetStart(aStartNode, aStartOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
-  if (aEndOffset)
-    rv = range->SetEnd(aEndNode, aEndOffset);
-  else
-    rv = range->SetEndAfter(aEndNode);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> startNode = do_QueryInterface(aStartNode);
+  nsCOMPtr<nsINode> endNode = do_QueryInterface(aEndNode);
+  if (aEndOffset) {
+    rv = range->SetStartAndEnd(startNode, aStartOffset, endNode, aEndOffset);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  } else {
+    int32_t endOffset = -1;
+    endNode = nsRange::GetParentAndOffsetAfter(endNode, &endOffset);
+    rv = range->SetStartAndEnd(startNode, aStartOffset, endNode, endOffset);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
 
-  *aRange = static_cast<nsRange*>(range.forget().take());
+  range.swap(*aRange);
   return NS_OK;
 }
 
diff --git a/extensions/spellcheck/src/mozInlineSpellChecker.h b/extensions/spellcheck/src/mozInlineSpellChecker.h
index 86d91c2c07..52261f22be 100644
--- a/extensions/spellcheck/src/mozInlineSpellChecker.h
+++ b/extensions/spellcheck/src/mozInlineSpellChecker.h
@@ -85,7 +85,7 @@ public:
   // (such as for the intial check of everything).
   //
   // For mOp == eOpNavigation, this is the NEW position of the cursor
-  nsCOMPtr<nsIDOMRange> mAnchorRange;
+  RefPtr<nsRange> mAnchorRange;
 
   // -----
   // The following members are only for navigation events and are only
@@ -93,7 +93,7 @@ public:
   // -----
 
   // this is the OLD position of the cursor
-  nsCOMPtr<nsIDOMRange> mOldNavigationAnchorRange;
+  RefPtr<nsRange> mOldNavigationAnchorRange;
 
   // Set when we should force checking the current word. See
   // mozInlineSpellChecker::HandleNavigationEvent for a description of why we
@@ -111,7 +111,7 @@ protected:
   nsresult GetDocument(nsIDOMDocument** aDocument);
   nsresult PositionToCollapsedRange(nsIDOMDocument* aDocument,
                                     nsIDOMNode* aNode, int32_t aOffset,
-                                    nsIDOMRange** aRange);
+                                    nsRange** aRange);
 };
 
 class mozInlineSpellChecker final : public nsIInlineSpellChecker,
diff --git a/extensions/spellcheck/src/mozInlineSpellWordUtil.cpp b/extensions/spellcheck/src/mozInlineSpellWordUtil.cpp
index 3aef1533d1..460ac46b85 100644
--- a/extensions/spellcheck/src/mozInlineSpellWordUtil.cpp
+++ b/extensions/spellcheck/src/mozInlineSpellWordUtil.cpp
@@ -336,9 +336,11 @@ mozInlineSpellWordUtil::MakeRange(NodeOffset aBegin, NodeOffset aEnd,
     return NS_ERROR_NOT_INITIALIZED;
 
   RefPtr<nsRange> range = new nsRange(aBegin.mNode);
-  nsresult rv = range->Set(aBegin.mNode, aBegin.mOffset,
-                           aEnd.mNode, aEnd.mOffset);
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsresult rv = range->SetStartAndEnd(aBegin.mNode, aBegin.mOffset,
+                                      aEnd.mNode, aEnd.mOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   range.forget(aRange);
 
   return NS_OK;
diff --git a/layout/forms/nsTextControlFrame.cpp b/layout/forms/nsTextControlFrame.cpp
index aa3185d39a..b34e132e60 100644
--- a/layout/forms/nsTextControlFrame.cpp
+++ b/layout/forms/nsTextControlFrame.cpp
@@ -758,7 +758,12 @@ nsTextControlFrame::SetSelectionInternal(nsIDOMNode *aStartNode,
   // we have access to the node.
   nsCOMPtr<nsINode> start = do_QueryInterface(aStartNode);
   nsCOMPtr<nsINode> end = do_QueryInterface(aEndNode);
-  nsresult rv = range->Set(start, aStartOffset, end, aEndOffset);
+  // XXXbz nsRange::SetStartAndEnd takes int32_t (and ranges generally work on
+  // int32_t), but we're passing uint32_t.  The good news is that at this point
+  // our endpoints should really be within our length, so not really that big.
+  // And if they _are_ that big, SetStartAndEnd() will simply error out, which
+  // is not too bad for a case we don't expect to happen.
+  nsresult rv = range->SetStartAndEnd(start, aStartOffset, end, aEndOffset);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // Get the selection, clear it and add the new range to it!
diff --git a/layout/generic/nsSelection.cpp b/layout/generic/nsSelection.cpp
index 5ccb2d8bf8..f44ff7ea12 100644
--- a/layout/generic/nsSelection.cpp
+++ b/layout/generic/nsSelection.cpp
@@ -1788,8 +1788,7 @@ nsFrameSelection::TakeFocus(nsIContent*        aNewFocus,
 
       RefPtr<nsRange> newRange = new nsRange(aNewFocus);
 
-      newRange->SetStart(aNewFocus, aContentOffset);
-      newRange->SetEnd(aNewFocus, aContentOffset);
+      newRange->CollapseTo(aNewFocus, aContentOffset);
       mDomSelections[index]->AddRange(newRange);
       mBatching = batching;
       mChangesDuringBatching = changes;
@@ -3352,10 +3351,11 @@ nsFrameSelection::CreateAndAddRange(nsINode *aParentNode, int32_t aOffset)
   RefPtr<nsRange> range = new nsRange(aParentNode);
 
   // Set range around child at given offset
-  nsresult result = range->SetStart(aParentNode, aOffset);
-  if (NS_FAILED(result)) return result;
-  result = range->SetEnd(aParentNode, aOffset+1);
-  if (NS_FAILED(result)) return result;
+  nsresult rv = range->SetStartAndEnd(aParentNode, aOffset,
+                                      aParentNode, aOffset + 1);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
   
   int8_t index = GetIndexFromSelectionType(SelectionType::eNormal);
   if (!mDomSelections[index])
@@ -3780,13 +3780,12 @@ Selection::SubtractRange(RangeData* aRange, nsRange* aSubtract,
     // We need to add a new RangeData to the output, running from
     // the end of aSubtract to the end of range
     RefPtr<nsRange> postOverlap = new nsRange(aSubtract->GetEndParent());
-
-    rv =
-      postOverlap->SetStart(aSubtract->GetEndParent(), aSubtract->EndOffset());
-    NS_ENSURE_SUCCESS(rv, rv);
-    rv =
-     postOverlap->SetEnd(range->GetEndParent(), range->EndOffset());
-    NS_ENSURE_SUCCESS(rv, rv);
+    rv = postOverlap->SetStartAndEnd(
+                        aSubtract->GetEndParent(), aSubtract->EndOffset(),
+                        range->GetEndParent(), range->EndOffset());
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
     if (!postOverlap->Collapsed()) {
       if (!aOutput->InsertElementAt(0, RangeData(postOverlap)))
         return NS_ERROR_OUT_OF_MEMORY;
@@ -3799,12 +3798,12 @@ Selection::SubtractRange(RangeData* aRange, nsRange* aSubtract,
     // the start of the range to the start of aSubtract
     RefPtr<nsRange> preOverlap = new nsRange(range->GetStartParent());
 
-    nsresult rv =
-     preOverlap->SetStart(range->GetStartParent(), range->StartOffset());
-    NS_ENSURE_SUCCESS(rv, rv);
-    rv =
-     preOverlap->SetEnd(aSubtract->GetStartParent(), aSubtract->StartOffset());
-    NS_ENSURE_SUCCESS(rv, rv);
+    rv = preOverlap->SetStartAndEnd(
+                       range->GetStartParent(), range->StartOffset(),
+                       aSubtract->GetStartParent(), aSubtract->StartOffset());
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
     
     if (!preOverlap->Collapsed()) {
       if (!aOutput->InsertElementAt(0, RangeData(preOverlap)))
@@ -5186,12 +5185,7 @@ Selection::Collapse(nsINode& aParentNode, uint32_t aOffset, ErrorResult& aRv)
   }
 
   RefPtr<nsRange> range = new nsRange(parentNode);
-  result = range->SetEnd(parentNode, aOffset);
-  if (NS_FAILED(result)) {
-    aRv.Throw(result);
-    return;
-  }
-  result = range->SetStart(parentNode, aOffset);
+  result = range->CollapseTo(parentNode, aOffset);
   if (NS_FAILED(result)) {
     aRv.Throw(result);
     return;
@@ -5579,11 +5573,8 @@ Selection::Extend(nsINode& aParentNode, uint32_t aOffset, ErrorResult& aRv)
       return;
     }
     SetDirection(eDirNext);
-    res = difRange->SetEnd(range->GetEndParent(), range->EndOffset());
-    nsresult tmp = difRange->SetStart(focusNode, focusOffset);
-    if (NS_FAILED(tmp)) {
-      res = tmp;
-    }
+    res = difRange->SetStartAndEnd(focusNode, focusOffset,
+                                   range->GetEndParent(), range->EndOffset());
     if (NS_FAILED(res)) {
       aRv.Throw(res);
       return;
@@ -5611,11 +5602,8 @@ Selection::Extend(nsINode& aParentNode, uint32_t aOffset, ErrorResult& aRv)
   }
   else if (result3 <= 0 && result2 >= 0) {//a,2,1 or a2,1 or a,21 or a21
     //deselect from 2 to 1
-    res = difRange->SetEnd(focusNode, focusOffset);
-    difRange->SetStart(aParentNode, aOffset, aRv);
-    if (aRv.Failed()) {
-      return;
-    }
+    res = difRange->SetStartAndEnd(&aParentNode, aOffset,
+                                   focusNode, focusOffset);
     if (NS_FAILED(res)) {
       aRv.Throw(res);
       return;
@@ -5678,11 +5666,8 @@ Selection::Extend(nsINode& aParentNode, uint32_t aOffset, ErrorResult& aRv)
   }
   else if (result2 <= 0 && result3 >= 0) {//1,2,a or 12,a or 1,2a or 12a
     //deselect from 1 to 2
-    difRange->SetEnd(aParentNode, aOffset, aRv);
-    res = difRange->SetStart(focusNode, focusOffset);
-    if (aRv.Failed()) {
-      return;
-    }
+    res = difRange->SetStartAndEnd(focusNode, focusOffset,
+                                   &aParentNode, aOffset);
     if (NS_FAILED(res)) {
       aRv.Throw(res);
       return;
@@ -5713,15 +5698,9 @@ Selection::Extend(nsINode& aParentNode, uint32_t aOffset, ErrorResult& aRv)
     }
     //deselect from a to 1
     if (focusNode != anchorNode || focusOffset!= anchorOffset) {//if collapsed diff dont do anything
-      res = difRange->SetStart(anchorNode, anchorOffset);
-      nsresult tmp = difRange->SetEnd(focusNode, focusOffset);
-      if (NS_FAILED(tmp)) {
-        res = tmp;
-      }
-      tmp = SetAnchorFocusToRange(range);
-      if (NS_FAILED(tmp)) {
-        res = tmp;
-      }
+      res = difRange->SetStartAndEnd(anchorNode, anchorOffset,
+                                     focusNode, focusOffset);
+      nsresult tmp = SetAnchorFocusToRange(range);
       if (NS_FAILED(res)) {
         aRv.Throw(res);
         return;
@@ -5746,11 +5725,9 @@ Selection::Extend(nsINode& aParentNode, uint32_t aOffset, ErrorResult& aRv)
       return;
     }
     SetDirection(eDirPrevious);
-    res = difRange->SetEnd(focusNode, focusOffset);
-    nsresult tmp = difRange->SetStart(range->GetStartParent(), range->StartOffset());
-    if (NS_FAILED(tmp)) {
-      res = tmp;
-    }
+    res = difRange->SetStartAndEnd(
+                      range->GetStartParent(), range->StartOffset(),
+                      focusNode, focusOffset);
     if (NS_FAILED(res)) {
       aRv.Throw(res);
       return;
diff --git a/layout/printing/nsPrintEngine.cpp b/layout/printing/nsPrintEngine.cpp
index f2db53250e..0c455f563f 100644
--- a/layout/printing/nsPrintEngine.cpp
+++ b/layout/printing/nsPrintEngine.cpp
@@ -2449,13 +2449,17 @@ CloneRangeToSelection(nsRange* aRange, nsIDocument* aDoc,
   NS_ENSURE_TRUE_VOID(newStart && newEnd);
 
   nsCOMPtr<nsINode> newStartNode = do_QueryInterface(newStart);
-  NS_ENSURE_TRUE_VOID(newStartNode);
+  nsCOMPtr<nsINode> newEndNode = do_QueryInterface(newEnd);
+  if (NS_WARN_IF(!newStartNode) || NS_WARN_IF(!newEndNode)) {
+    return;
+  }
 
   RefPtr<nsRange> range = new nsRange(newStartNode);
-  nsresult rv = range->SetStart(newStartNode, startOffset);
-  NS_ENSURE_SUCCESS_VOID(rv);
-  rv = range->SetEnd(newEnd, endOffset);
-  NS_ENSURE_SUCCESS_VOID(rv);
+  nsresult rv =
+    range->SetStartAndEnd(newStartNode, startOffset, newEndNode, endOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
 
   aSelection->AddRange(range);
 }