Make InlineContents traverse flat tree for previous and next

Currently, InlineContents creation and previous/next movement are done by different implementations: - When creating from a position, it traverses the flat tree until finding a node in a usable block flow; - When moving previous/next, it traverses the layout tree until finding a useable block flow. Since these operations are very similar, this patch change the latter to also traverse on flat tree and share the traversal algorithm to reduce duplicated logic. This also makes it easier to change TextOffsetMapping not to cross text control boundaries (*). (*) crrev.com/c/1327962 Bug: 901492 Change-Id: If7c3dd262903c1a0f81166f729614a8d810f5d27 Reviewed-on: https://chromium-review.googlesource.com/c/1327531Reviewed-by: Yoshifumi Inoue <yosin@chromium.org> Reviewed-by: Yoichi Osato <yoichio@chromium.org> Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org> Cr-Commit-Position: refs/heads/master@{#606748}

Make InlineContents traverse flat tree for previous and next
Currently, InlineContents creation and previous/next movement are done by different implementations: - When creating from a position, it traverses the flat tree until finding a node in a usable block flow; - When moving previous/next, it traverses the layout tree until finding a useable block flow. Since these operations are very similar, this patch change the latter to also traverse on flat tree and share the traversal algorithm to reduce duplicated logic. This also makes it easier to change TextOffsetMapping not to cross text control boundaries (*). (*) crrev.com/c/1327962 Bug: 901492 Change-Id: If7c3dd262903c1a0f81166f729614a8d810f5d27 Reviewed-on: https://chromium-review.googlesource.com/c/1327531Reviewed-by: Yoshifumi Inoue <yosin@chromium.org> Reviewed-by: Yoichi Osato <yoichio@chromium.org> Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org> Cr-Commit-Position: refs/heads/master@{#606748}
4d281c8d · Xiaocheng Hu · Commit Bot · 7d6ae34d · 4d281c8d · 4d281c8d
Commit 4d281c8d authored Nov 09, 2018 by Xiaocheng Hu Committed by Commit Bot Nov 09, 2018
2 changed files
--- a/third_party/blink/renderer/core/editing/text_offset_mapping.cc
+++ b/third_party/blink/renderer/core/editing/text_offset_mapping.cc
@@ -235,6 +235,7 @@ TextOffsetMapping::ForwardRange TextOffsetMapping::ForwardRangeOf(
 // static
 TextOffsetMapping::InlineContents TextOffsetMapping::FindBackwardInlineContents(
    const PositionInFlatTree& position) {
+  // TODO(xiaochengh): Make this function not cross text control boundaries.
  for (const Node* node = position.NodeAsRangeLastNode(); node;
       node = FlatTreeTraversal::Previous(*node)) {
    const InlineContents inline_contents = ComputeInlineContentsFromNode(*node);
@@ -249,6 +250,7 @@ TextOffsetMapping::InlineContents TextOffsetMapping::FindBackwardInlineContents(
 // with AfterNode(IMG) for <body><img></body>
 TextOffsetMapping::InlineContents TextOffsetMapping::FindForwardInlineContents(
    const PositionInFlatTree& position) {
+  // TODO(xiaochengh): Make this function not cross text control boundaries.
  for (const Node* node = position.NodeAsRangeFirstNode(); node;
       node = FlatTreeTraversal::Next(*node)) {
    const InlineContents inline_contents = ComputeInlineContentsFromNode(*node);
@@ -323,38 +325,38 @@ EphemeralRangeInFlatTree TextOffsetMapping::InlineContents::GetRange() const {
          : PositionInFlatTree::AfterNode(last_node));
 }

+PositionInFlatTree
+TextOffsetMapping::InlineContents::LastPositionBeforeBlockFlow() const {
+  DCHECK(block_flow_);
+  if (const Node* node = block_flow_->NonPseudoNode())
+    return PositionInFlatTree::BeforeNode(*node);
+  DCHECK(first_);
+  DCHECK(first_->NonPseudoNode());
+  return PositionInFlatTree::BeforeNode(*first_->NonPseudoNode());
+}
+
+PositionInFlatTree
+TextOffsetMapping::InlineContents::FirstPositionAfterBlockFlow() const {
+  DCHECK(block_flow_);
+  if (const Node* node = block_flow_->NonPseudoNode())
+    return PositionInFlatTree::AfterNode(*node);
+  DCHECK(last_);
+  DCHECK(last_->NonPseudoNode());
+  return PositionInFlatTree::AfterNode(*last_->NonPseudoNode());
+}
+
 // static
 TextOffsetMapping::InlineContents TextOffsetMapping::InlineContents::NextOf(
    const InlineContents& inline_contents) {
-  for (LayoutObject* runner =
-           inline_contents.block_flow_->NextInPreOrderAfterChildren();
-       runner; runner = runner->NextInPreOrder()) {
-    if (!CanBeInlineContentsContainer(*runner))
-      continue;
-    const LayoutBlockFlow& block_flow = ToLayoutBlockFlow(*runner);
-    if (block_flow.IsFloatingOrOutOfFlowPositioned())
-      continue;
-    DCHECK(!block_flow.IsAtomicInlineLevel()) << block_flow;
-    return CreateInlineContentsFromBlockFlow(block_flow);
-  }
-  return InlineContents();
+  return TextOffsetMapping::FindForwardInlineContents(
+      inline_contents.FirstPositionAfterBlockFlow());
 }

 // static
 TextOffsetMapping::InlineContents TextOffsetMapping::InlineContents::PreviousOf(
    const InlineContents& inline_contents) {
-  for (LayoutObject* runner = inline_contents.block_flow_->PreviousInPreOrder();
-       runner; runner = runner->PreviousInPreOrder()) {
-    const LayoutBlockFlow* const block_flow =
-        ComputeInlineContentsAsBlockFlow(*runner);
-    if (!block_flow || block_flow->IsFloatingOrOutOfFlowPositioned())
-      continue;
-    DCHECK(!block_flow->IsDescendantOf(inline_contents.block_flow_))
-        << block_flow;
-    DCHECK(!block_flow->IsAtomicInlineLevel()) << block_flow;
-    return CreateInlineContentsFromBlockFlow(*block_flow);
-  }
-  return InlineContents();
+  return TextOffsetMapping::FindBackwardInlineContents(
+      inline_contents.LastPositionBeforeBlockFlow());
 }

 std::ostream& operator<<(

--- a/third_party/blink/renderer/core/editing/text_offset_mapping.h
+++ b/third_party/blink/renderer/core/editing/text_offset_mapping.h
@@ -71,6 +71,9 @@ class CORE_EXPORT TextOffsetMapping final {
   private:
    friend class TextOffsetMapping;

+    PositionInFlatTree FirstPositionAfterBlockFlow() const;
+    PositionInFlatTree LastPositionBeforeBlockFlow() const;
+
    const LayoutBlockFlow* block_flow_ = nullptr;
    const LayoutObject* first_ = nullptr;
    const LayoutObject* last_ = nullptr;