Bug 1367683 - Optimize initializing nsRange

Tag #1375

4 files changed, 146 insertions, 43 deletions

diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index d0e861b1a..e16c1831c 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 d45a2c975..154b3428f 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 4b35c749a..70911338d 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 935ade23f..df54a4d44 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;
   }