Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2787 insertions, 0 deletions

diff --git a/editor/spellchecker/TextServicesDocument.cpp b/editor/spellchecker/TextServicesDocument.cpp
new file mode 100644
index 0000000000..1417cf79ae
--- /dev/null
+++ b/editor/spellchecker/TextServicesDocument.cpp
@@ -0,0 +1,2787 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TextServicesDocument.h"
+
+#include "EditorBase.h"               // for EditorBase
+#include "EditorUtils.h"              // for AutoTransactionBatchExternal
+#include "FilteredContentIterator.h"  // for FilteredContentIterator
+#include "HTMLEditHelpers.h"          // for BlockInlineCheck
+#include "HTMLEditUtils.h"            // for HTMLEditUtils
+
+#include "mozilla/Assertions.h"    // for MOZ_ASSERT, etc
+#include "mozilla/IntegerRange.h"  // for IntegerRange
+#include "mozilla/mozalloc.h"      // for operator new, etc
+#include "mozilla/OwningNonNull.h"
+#include "mozilla/UniquePtr.h"          // for UniquePtr
+#include "mozilla/dom/AbstractRange.h"  // for AbstractRange
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Selection.h"
+#include "mozilla/dom/StaticRange.h"  // for StaticRange
+#include "mozilla/dom/Text.h"
+#include "mozilla/intl/WordBreaker.h"  // for WordRange, WordBreaker
+
+#include "nsAString.h"       // for nsAString::Length, etc
+#include "nsContentUtils.h"  // for nsContentUtils
+#include "nsComposeTxtSrvFilter.h"
+#include "nsDebug.h"                 // for NS_ENSURE_TRUE, etc
+#include "nsDependentSubstring.h"    // for Substring
+#include "nsError.h"                 // for NS_OK, NS_ERROR_FAILURE, etc
+#include "nsGenericHTMLElement.h"    // for nsGenericHTMLElement
+#include "nsIContent.h"              // for nsIContent, etc
+#include "nsID.h"                    // for NS_GET_IID
+#include "nsIEditor.h"               // for nsIEditor, etc
+#include "nsIEditorSpellCheck.h"     // for nsIEditorSpellCheck, etc
+#include "nsINode.h"                 // for nsINode
+#include "nsISelectionController.h"  // for nsISelectionController, etc
+#include "nsISupports.h"             // for nsISupports
+#include "nsISupportsUtils.h"        // for NS_IF_ADDREF, NS_ADDREF, etc
+#include "nsRange.h"                 // for nsRange
+#include "nsString.h"                // for nsString, nsAutoString
+#include "nscore.h"                  // for nsresult, NS_IMETHODIMP, etc
+
+namespace mozilla {
+
+using namespace dom;
+
+/**
+ * OffsetEntry manages a range in a text node.  It stores 2 offset values,
+ * one is offset in the text node, the other is offset in all text in
+ * the ancestor block of the text node.  And the length is managing length
+ * in the text node, starting from the offset in text node.
+ * In other words, a text node may be managed by multiple instances of this
+ * class.
+ */
+class OffsetEntry final {
+ public:
+  OffsetEntry() = delete;
+
+  /**
+   * @param aTextNode   The text node which will be manged by the instance.
+   * @param aOffsetInTextInBlock
+   *                    Start offset in the text node which will be managed by
+   *                    the instance.
+   * @param aLength     Length in the text node which will be managed by the
+   *                    instance.
+   */
+  OffsetEntry(Text& aTextNode, uint32_t aOffsetInTextInBlock, uint32_t aLength)
+      : mTextNode(aTextNode),
+        mOffsetInTextNode(0),
+        mOffsetInTextInBlock(aOffsetInTextInBlock),
+        mLength(aLength),
+        mIsInsertedText(false),
+        mIsValid(true) {}
+
+  /**
+   * EndOffsetInTextNode() returns end offset in the text node, which is
+   * managed by the instance.
+   */
+  uint32_t EndOffsetInTextNode() const { return mOffsetInTextNode + mLength; }
+
+  /**
+   * OffsetInTextNodeIsInRangeOrEndOffset() checks whether the offset in
+   * the text node is managed by the instance or not.
+   */
+  bool OffsetInTextNodeIsInRangeOrEndOffset(uint32_t aOffsetInTextNode) const {
+    return aOffsetInTextNode >= mOffsetInTextNode &&
+           aOffsetInTextNode <= EndOffsetInTextNode();
+  }
+
+  /**
+   * EndOffsetInTextInBlock() returns end offset in the all text in ancestor
+   * block of the text node, which is managed by the instance.
+   */
+  uint32_t EndOffsetInTextInBlock() const {
+    return mOffsetInTextInBlock + mLength;
+  }
+
+  /**
+   * OffsetInTextNodeIsInRangeOrEndOffset() checks whether the offset in
+   * the all text in ancestor block of the text node is managed by the instance
+   * or not.
+   */
+  bool OffsetInTextInBlockIsInRangeOrEndOffset(
+      uint32_t aOffsetInTextInBlock) const {
+    return aOffsetInTextInBlock >= mOffsetInTextInBlock &&
+           aOffsetInTextInBlock <= EndOffsetInTextInBlock();
+  }
+
+  OwningNonNull<Text> mTextNode;
+  uint32_t mOffsetInTextNode;
+  // Offset in all text in the closest ancestor block of mTextNode.
+  uint32_t mOffsetInTextInBlock;
+  uint32_t mLength;
+  bool mIsInsertedText;
+  bool mIsValid;
+};
+
+template <typename ElementType>
+struct MOZ_STACK_CLASS ArrayLengthMutationGuard final {
+  ArrayLengthMutationGuard() = delete;
+  explicit ArrayLengthMutationGuard(const nsTArray<ElementType>& aArray)
+      : mArray(aArray), mOldLength(aArray.Length()) {}
+  ~ArrayLengthMutationGuard() {
+    if (mArray.Length() != mOldLength) {
+      MOZ_CRASH("The array length was changed unexpectedly");
+    }
+  }
+
+ private:
+  const nsTArray<ElementType>& mArray;
+  size_t mOldLength;
+};
+
+#define LockOffsetEntryArrayLengthInDebugBuild(aName, aArray)               \
+  DebugOnly<ArrayLengthMutationGuard<UniquePtr<OffsetEntry>>> const aName = \
+      ArrayLengthMutationGuard<UniquePtr<OffsetEntry>>(aArray);
+
+TextServicesDocument::TextServicesDocument()
+    : mTxtSvcFilterType(0), mIteratorStatus(IteratorStatus::eDone) {}
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(TextServicesDocument)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(TextServicesDocument)
+
+NS_INTERFACE_MAP_BEGIN(TextServicesDocument)
+  NS_INTERFACE_MAP_ENTRY(nsIEditActionListener)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIEditActionListener)
+  NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(TextServicesDocument)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTION(TextServicesDocument, mDocument, mSelCon, mEditorBase,
+                         mFilteredIter, mPrevTextBlock, mNextTextBlock, mExtent)
+
+nsresult TextServicesDocument::InitWithEditor(nsIEditor* aEditor) {
+  nsCOMPtr<nsISelectionController> selCon;
+
+  NS_ENSURE_TRUE(aEditor, NS_ERROR_NULL_POINTER);
+
+  // Check to see if we already have an mSelCon. If we do, it
+  // better be the same one the editor uses!
+
+  nsresult rv = aEditor->GetSelectionController(getter_AddRefs(selCon));
+
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!selCon || (mSelCon && selCon != mSelCon)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!mSelCon) {
+    mSelCon = selCon;
+  }
+
+  // Check to see if we already have an mDocument. If we do, it
+  // better be the same one the editor uses!
+
+  RefPtr<Document> doc = aEditor->AsEditorBase()->GetDocument();
+  if (!doc || (mDocument && doc != mDocument)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!mDocument) {
+    mDocument = doc;
+
+    rv = CreateDocumentContentIterator(getter_AddRefs(mFilteredIter));
+
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    mIteratorStatus = IteratorStatus::eDone;
+
+    rv = FirstBlock();
+
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  mEditorBase = aEditor->AsEditorBase();
+
+  rv = aEditor->AddEditActionListener(this);
+
+  return rv;
+}
+
+nsresult TextServicesDocument::SetExtent(const AbstractRange* aAbstractRange) {
+  MOZ_ASSERT(aAbstractRange);
+
+  if (NS_WARN_IF(!mDocument)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // We need to store a copy of aAbstractRange since we don't know where it
+  // came from.
+  mExtent = nsRange::Create(aAbstractRange, IgnoreErrors());
+  if (NS_WARN_IF(!mExtent)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Create a new iterator based on our new extent range.
+  nsresult rv =
+      CreateFilteredContentIterator(mExtent, getter_AddRefs(mFilteredIter));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Now position the iterator at the start of the first block
+  // in the range.
+  mIteratorStatus = IteratorStatus::eDone;
+
+  rv = FirstBlock();
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "FirstBlock() failed");
+  return rv;
+}
+
+nsresult TextServicesDocument::ExpandRangeToWordBoundaries(
+    StaticRange* aStaticRange) {
+  MOZ_ASSERT(aStaticRange);
+
+  // Get the end points of the range.
+
+  nsCOMPtr<nsINode> rngStartNode, rngEndNode;
+  uint32_t rngStartOffset, rngEndOffset;
+
+  nsresult rv = GetRangeEndPoints(aStaticRange, getter_AddRefs(rngStartNode),
+                                  &rngStartOffset, getter_AddRefs(rngEndNode),
+                                  &rngEndOffset);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Create a content iterator based on the range.
+  RefPtr<FilteredContentIterator> filteredIter;
+  rv =
+      CreateFilteredContentIterator(aStaticRange, getter_AddRefs(filteredIter));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Find the first text node in the range.
+  IteratorStatus iterStatus = IteratorStatus::eDone;
+  rv = FirstTextNode(filteredIter, &iterStatus);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (iterStatus == IteratorStatus::eDone) {
+    // No text was found so there's no adjustment necessary!
+    return NS_OK;
+  }
+
+  nsINode* firstText = filteredIter->GetCurrentNode();
+  if (NS_WARN_IF(!firstText)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Find the last text node in the range.
+
+  rv = LastTextNode(filteredIter, &iterStatus);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (iterStatus == IteratorStatus::eDone) {
+    // We should never get here because a first text block
+    // was found above.
+    NS_ASSERTION(false, "Found a first without a last!");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsINode* lastText = filteredIter->GetCurrentNode();
+  if (NS_WARN_IF(!lastText)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Now make sure our end points are in terms of text nodes in the range!
+
+  if (rngStartNode != firstText) {
+    // The range includes the start of the first text node!
+    rngStartNode = firstText;
+    rngStartOffset = 0;
+  }
+
+  if (rngEndNode != lastText) {
+    // The range includes the end of the last text node!
+    rngEndNode = lastText;
+    rngEndOffset = lastText->Length();
+  }
+
+  // Create a doc iterator so that we can scan beyond
+  // the bounds of the extent range.
+
+  RefPtr<FilteredContentIterator> docFilteredIter;
+  rv = CreateDocumentContentIterator(getter_AddRefs(docFilteredIter));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Grab all the text in the block containing our
+  // first text node.
+  rv = docFilteredIter->PositionAt(firstText);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  iterStatus = IteratorStatus::eValid;
+
+  OffsetEntryArray offsetTable;
+  nsAutoString blockStr;
+  Result<IteratorStatus, nsresult> result = offsetTable.Init(
+      *docFilteredIter, IteratorStatus::eValid, nullptr, &blockStr);
+  if (result.isErr()) {
+    return result.unwrapErr();
+  }
+
+  Result<EditorDOMRangeInTexts, nsresult> maybeWordRange =
+      offsetTable.FindWordRange(
+          blockStr, EditorRawDOMPoint(rngStartNode, rngStartOffset));
+  offsetTable.Clear();
+  if (maybeWordRange.isErr()) {
+    NS_WARNING(
+        "TextServicesDocument::OffsetEntryArray::FindWordRange() failed");
+    return maybeWordRange.unwrapErr();
+  }
+  rngStartNode = maybeWordRange.inspect().StartRef().GetContainerAs<Text>();
+  rngStartOffset = maybeWordRange.inspect().StartRef().Offset();
+
+  // Grab all the text in the block containing our
+  // last text node.
+
+  rv = docFilteredIter->PositionAt(lastText);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  result = offsetTable.Init(*docFilteredIter, IteratorStatus::eValid, nullptr,
+                            &blockStr);
+  if (result.isErr()) {
+    return result.unwrapErr();
+  }
+
+  maybeWordRange = offsetTable.FindWordRange(
+      blockStr, EditorRawDOMPoint(rngEndNode, rngEndOffset));
+  offsetTable.Clear();
+  if (maybeWordRange.isErr()) {
+    NS_WARNING(
+        "TextServicesDocument::OffsetEntryArray::FindWordRange() failed");
+    return maybeWordRange.unwrapErr();
+  }
+
+  // To prevent expanding the range too much, we only change
+  // rngEndNode and rngEndOffset if it isn't already at the start of the
+  // word and isn't equivalent to rngStartNode and rngStartOffset.
+
+  if (rngEndNode !=
+          maybeWordRange.inspect().StartRef().GetContainerAs<Text>() ||
+      rngEndOffset != maybeWordRange.inspect().StartRef().Offset() ||
+      (rngEndNode == rngStartNode && rngEndOffset == rngStartOffset)) {
+    rngEndNode = maybeWordRange.inspect().EndRef().GetContainerAs<Text>();
+    rngEndOffset = maybeWordRange.inspect().EndRef().Offset();
+  }
+
+  // Now adjust the range so that it uses our new end points.
+  rv = aStaticRange->SetStartAndEnd(rngStartNode, rngStartOffset, rngEndNode,
+                                    rngEndOffset);
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Failed to update the given range");
+  return rv;
+}
+
+nsresult TextServicesDocument::SetFilterType(uint32_t aFilterType) {
+  mTxtSvcFilterType = aFilterType;
+
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::GetCurrentTextBlock(nsAString& aStr) {
+  aStr.Truncate();
+
+  NS_ENSURE_TRUE(mFilteredIter, NS_ERROR_FAILURE);
+
+  Result<IteratorStatus, nsresult> result =
+      mOffsetTable.Init(*mFilteredIter, mIteratorStatus, mExtent, &aStr);
+  if (result.isErr()) {
+    NS_WARNING("OffsetEntryArray::Init() failed");
+    return result.unwrapErr();
+  }
+  mIteratorStatus = result.unwrap();
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::FirstBlock() {
+  NS_ENSURE_TRUE(mFilteredIter, NS_ERROR_FAILURE);
+
+  nsresult rv = FirstTextNode(mFilteredIter, &mIteratorStatus);
+
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Keep track of prev and next blocks, just in case
+  // the text service blows away the current block.
+
+  if (mIteratorStatus == IteratorStatus::eValid) {
+    mPrevTextBlock = nullptr;
+    rv = GetFirstTextNodeInNextBlock(getter_AddRefs(mNextTextBlock));
+  } else {
+    // There's no text block in the document!
+
+    mPrevTextBlock = nullptr;
+    mNextTextBlock = nullptr;
+  }
+
+  // XXX Result of FirstTextNode() or GetFirstTextNodeInNextBlock().
+  return rv;
+}
+
+nsresult TextServicesDocument::LastSelectedBlock(
+    BlockSelectionStatus* aSelStatus, uint32_t* aSelOffset,
+    uint32_t* aSelLength) {
+  NS_ENSURE_TRUE(aSelStatus && aSelOffset && aSelLength, NS_ERROR_NULL_POINTER);
+
+  mIteratorStatus = IteratorStatus::eDone;
+
+  *aSelStatus = BlockSelectionStatus::eBlockNotFound;
+  *aSelOffset = *aSelLength = UINT32_MAX;
+
+  if (!mSelCon || !mFilteredIter) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<Selection> selection =
+      mSelCon->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  if (NS_WARN_IF(!selection)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<const nsRange> range;
+  nsCOMPtr<nsINode> parent;
+
+  if (selection->IsCollapsed()) {
+    // We have a caret. Check if the caret is in a text node.
+    // If it is, make the text node's block the current block.
+    // If the caret isn't in a text node, search forwards in
+    // the document, till we find a text node.
+
+    range = selection->GetRangeAt(0);
+    if (!range) {
+      return NS_ERROR_FAILURE;
+    }
+
+    parent = range->GetStartContainer();
+    if (!parent) {
+      return NS_ERROR_FAILURE;
+    }
+
+    nsresult rv;
+    if (parent->IsText()) {
+      // The caret is in a text node. Find the beginning
+      // of the text block containing this text node and
+      // return.
+
+      rv = mFilteredIter->PositionAt(parent->AsText());
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      rv = FirstTextNodeInCurrentBlock(mFilteredIter);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      Result<IteratorStatus, nsresult> result =
+          mOffsetTable.Init(*mFilteredIter, IteratorStatus::eValid, mExtent);
+      if (result.isErr()) {
+        NS_WARNING("OffsetEntryArray::Init() failed");
+        mIteratorStatus = IteratorStatus::eValid;  // XXX
+        return result.unwrapErr();
+      }
+      mIteratorStatus = result.unwrap();
+
+      rv = GetSelection(aSelStatus, aSelOffset, aSelLength);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      if (*aSelStatus == BlockSelectionStatus::eBlockContains) {
+        rv = SetSelectionInternal(*aSelOffset, *aSelLength, false);
+      }
+    } else {
+      // The caret isn't in a text node. Create an iterator
+      // based on a range that extends from the current caret
+      // position to the end of the document, then walk forwards
+      // till you find a text node, then find the beginning of it's block.
+
+      range = CreateDocumentContentRootToNodeOffsetRange(
+          parent, range->StartOffset(), false);
+      if (NS_WARN_IF(!range)) {
+        return NS_ERROR_FAILURE;
+      }
+
+      if (range->Collapsed()) {
+        // If we get here, the range is collapsed because there is nothing after
+        // the caret! Just return NS_OK;
+        return NS_OK;
+      }
+
+      RefPtr<FilteredContentIterator> filteredIter;
+      rv = CreateFilteredContentIterator(range, getter_AddRefs(filteredIter));
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      filteredIter->First();
+
+      Text* textNode = nullptr;
+      for (; !filteredIter->IsDone(); filteredIter->Next()) {
+        nsINode* currentNode = filteredIter->GetCurrentNode();
+        if (currentNode->IsText()) {
+          textNode = currentNode->AsText();
+          break;
+        }
+      }
+
+      if (!textNode) {
+        return NS_OK;
+      }
+
+      rv = mFilteredIter->PositionAt(textNode);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      rv = FirstTextNodeInCurrentBlock(mFilteredIter);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      Result<IteratorStatus, nsresult> result = mOffsetTable.Init(
+          *mFilteredIter, IteratorStatus::eValid, mExtent, nullptr);
+      if (result.isErr()) {
+        NS_WARNING("OffsetEntryArray::Init() failed");
+        mIteratorStatus = IteratorStatus::eValid;  // XXX
+        return result.unwrapErr();
+      }
+      mIteratorStatus = result.inspect();
+
+      rv = GetSelection(aSelStatus, aSelOffset, aSelLength);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+    }
+
+    // Result of SetSelectionInternal() in the |if| block or NS_OK.
+    return rv;
+  }
+
+  // If we get here, we have an uncollapsed selection!
+  // Look backwards through each range in the selection till you
+  // find the first text node. If you find one, find the
+  // beginning of its text block, and make it the current
+  // block.
+
+  const uint32_t rangeCount = selection->RangeCount();
+  MOZ_ASSERT(
+      rangeCount,
+      "Selection is not collapsed, so, the range count should be 1 or larger");
+
+  // XXX: We may need to add some code here to make sure
+  //      the ranges are sorted in document appearance order!
+
+  for (const uint32_t i : Reversed(IntegerRange(rangeCount))) {
+    MOZ_ASSERT(selection->RangeCount() == rangeCount);
+    range = selection->GetRangeAt(i);
+    if (MOZ_UNLIKELY(!range)) {
+      return NS_OK;  // XXX Really?
+    }
+
+    // Create an iterator for the range.
+
+    RefPtr<FilteredContentIterator> filteredIter;
+    nsresult rv =
+        CreateFilteredContentIterator(range, getter_AddRefs(filteredIter));
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    filteredIter->Last();
+
+    // Now walk through the range till we find a text node.
+
+    for (; !filteredIter->IsDone(); filteredIter->Prev()) {
+      if (filteredIter->GetCurrentNode()->NodeType() == nsINode::TEXT_NODE) {
+        // We found a text node, so position the document's
+        // iterator at the beginning of the block, then get
+        // the selection in terms of the string offset.
+
+        nsresult rv = mFilteredIter->PositionAt(filteredIter->GetCurrentNode());
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+
+        rv = FirstTextNodeInCurrentBlock(mFilteredIter);
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+
+        mIteratorStatus = IteratorStatus::eValid;
+
+        Result<IteratorStatus, nsresult> result =
+            mOffsetTable.Init(*mFilteredIter, IteratorStatus::eValid, mExtent);
+        if (result.isErr()) {
+          NS_WARNING("OffsetEntryArray::Init() failed");
+          mIteratorStatus = IteratorStatus::eValid;  // XXX
+          return result.unwrapErr();
+        }
+        mIteratorStatus = result.unwrap();
+
+        return GetSelection(aSelStatus, aSelOffset, aSelLength);
+      }
+    }
+  }
+
+  // If we get here, we didn't find any text node in the selection!
+  // Create a range that extends from the end of the selection,
+  // to the end of the document, then iterate forwards through
+  // it till you find a text node!
+  range = rangeCount > 0 ? selection->GetRangeAt(rangeCount - 1) : nullptr;
+  if (!range) {
+    return NS_ERROR_FAILURE;
+  }
+
+  parent = range->GetEndContainer();
+  if (!parent) {
+    return NS_ERROR_FAILURE;
+  }
+
+  range = CreateDocumentContentRootToNodeOffsetRange(parent, range->EndOffset(),
+                                                     false);
+  if (NS_WARN_IF(!range)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (range->Collapsed()) {
+    // If we get here, the range is collapsed because there is nothing after
+    // the current selection! Just return NS_OK;
+    return NS_OK;
+  }
+
+  RefPtr<FilteredContentIterator> filteredIter;
+  nsresult rv =
+      CreateFilteredContentIterator(range, getter_AddRefs(filteredIter));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  filteredIter->First();
+
+  for (; !filteredIter->IsDone(); filteredIter->Next()) {
+    if (filteredIter->GetCurrentNode()->NodeType() == nsINode::TEXT_NODE) {
+      // We found a text node! Adjust the document's iterator to point
+      // to the beginning of its text block, then get the current selection.
+      nsresult rv = mFilteredIter->PositionAt(filteredIter->GetCurrentNode());
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      rv = FirstTextNodeInCurrentBlock(mFilteredIter);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      Result<IteratorStatus, nsresult> result =
+          mOffsetTable.Init(*mFilteredIter, IteratorStatus::eValid, mExtent);
+      if (result.isErr()) {
+        NS_WARNING("OffsetEntryArray::Init() failed");
+        mIteratorStatus = IteratorStatus::eValid;  // XXX
+        return result.unwrapErr();
+      }
+      mIteratorStatus = result.unwrap();
+
+      rv = GetSelection(aSelStatus, aSelOffset, aSelLength);
+      NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                           "TextServicesDocument::GetSelection() failed");
+      return rv;
+    }
+  }
+
+  // If we get here, we didn't find any block before or inside
+  // the selection! Just return OK.
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::PrevBlock() {
+  NS_ENSURE_TRUE(mFilteredIter, NS_ERROR_FAILURE);
+
+  if (mIteratorStatus == IteratorStatus::eDone) {
+    return NS_OK;
+  }
+
+  switch (mIteratorStatus) {
+    case IteratorStatus::eValid:
+    case IteratorStatus::eNext: {
+      nsresult rv = FirstTextNodeInPrevBlock(mFilteredIter);
+
+      if (NS_FAILED(rv)) {
+        mIteratorStatus = IteratorStatus::eDone;
+        return rv;
+      }
+
+      if (mFilteredIter->IsDone()) {
+        mIteratorStatus = IteratorStatus::eDone;
+        return NS_OK;
+      }
+
+      mIteratorStatus = IteratorStatus::eValid;
+      break;
+    }
+    case IteratorStatus::ePrev:
+
+      // The iterator already points to the previous
+      // block, so don't do anything.
+
+      mIteratorStatus = IteratorStatus::eValid;
+      break;
+
+    default:
+
+      mIteratorStatus = IteratorStatus::eDone;
+      break;
+  }
+
+  // Keep track of prev and next blocks, just in case
+  // the text service blows away the current block.
+  nsresult rv = NS_OK;
+  if (mIteratorStatus == IteratorStatus::eValid) {
+    GetFirstTextNodeInPrevBlock(getter_AddRefs(mPrevTextBlock));
+    rv = GetFirstTextNodeInNextBlock(getter_AddRefs(mNextTextBlock));
+  } else {
+    // We must be done!
+    mPrevTextBlock = nullptr;
+    mNextTextBlock = nullptr;
+  }
+
+  // XXX The result of GetFirstTextNodeInNextBlock() or NS_OK.
+  return rv;
+}
+
+nsresult TextServicesDocument::NextBlock() {
+  NS_ENSURE_TRUE(mFilteredIter, NS_ERROR_FAILURE);
+
+  if (mIteratorStatus == IteratorStatus::eDone) {
+    return NS_OK;
+  }
+
+  switch (mIteratorStatus) {
+    case IteratorStatus::eValid: {
+      // Advance the iterator to the next text block.
+
+      nsresult rv = FirstTextNodeInNextBlock(mFilteredIter);
+
+      if (NS_FAILED(rv)) {
+        mIteratorStatus = IteratorStatus::eDone;
+        return rv;
+      }
+
+      if (mFilteredIter->IsDone()) {
+        mIteratorStatus = IteratorStatus::eDone;
+        return NS_OK;
+      }
+
+      mIteratorStatus = IteratorStatus::eValid;
+      break;
+    }
+    case IteratorStatus::eNext:
+
+      // The iterator already points to the next block,
+      // so don't do anything to it!
+
+      mIteratorStatus = IteratorStatus::eValid;
+      break;
+
+    case IteratorStatus::ePrev:
+
+      // If the iterator is pointing to the previous block,
+      // we know that there is no next text block! Just
+      // fall through to the default case!
+
+    default:
+
+      mIteratorStatus = IteratorStatus::eDone;
+      break;
+  }
+
+  // Keep track of prev and next blocks, just in case
+  // the text service blows away the current block.
+  nsresult rv = NS_OK;
+  if (mIteratorStatus == IteratorStatus::eValid) {
+    GetFirstTextNodeInPrevBlock(getter_AddRefs(mPrevTextBlock));
+    rv = GetFirstTextNodeInNextBlock(getter_AddRefs(mNextTextBlock));
+  } else {
+    // We must be done.
+    mPrevTextBlock = nullptr;
+    mNextTextBlock = nullptr;
+  }
+
+  // The result of GetFirstTextNodeInNextBlock() or NS_OK.
+  return rv;
+}
+
+nsresult TextServicesDocument::IsDone(bool* aIsDone) {
+  NS_ENSURE_TRUE(aIsDone, NS_ERROR_NULL_POINTER);
+
+  *aIsDone = false;
+
+  NS_ENSURE_TRUE(mFilteredIter, NS_ERROR_FAILURE);
+
+  *aIsDone = mIteratorStatus == IteratorStatus::eDone;
+
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::SetSelection(uint32_t aOffset,
+                                            uint32_t aLength) {
+  NS_ENSURE_TRUE(mSelCon, NS_ERROR_FAILURE);
+
+  return SetSelectionInternal(aOffset, aLength, true);
+}
+
+nsresult TextServicesDocument::ScrollSelectionIntoView() {
+  NS_ENSURE_TRUE(mSelCon, NS_ERROR_FAILURE);
+
+  // After ScrollSelectionIntoView(), the pending notifications might be flushed
+  // and PresShell/PresContext/Frames may be dead. See bug 418470.
+  nsresult rv = mSelCon->ScrollSelectionIntoView(
+      nsISelectionController::SELECTION_NORMAL,
+      nsISelectionController::SELECTION_FOCUS_REGION,
+      nsISelectionController::SCROLL_SYNCHRONOUS);
+
+  return rv;
+}
+
+nsresult TextServicesDocument::OffsetEntryArray::WillDeleteSelection() {
+  MOZ_ASSERT(mSelection.IsSet());
+  MOZ_ASSERT(!mSelection.IsCollapsed());
+
+  for (size_t i = mSelection.StartIndex(); i <= mSelection.EndIndex(); i++) {
+    OffsetEntry* entry = ElementAt(i).get();
+    if (i == mSelection.StartIndex()) {
+      // Calculate the length of the selection. Note that the
+      // selection length can be zero if the start of the selection
+      // is at the very end of a text node entry.
+      uint32_t selLength;
+      if (entry->mIsInsertedText) {
+        // Inserted text offset entries have no width when
+        // talking in terms of string offsets! If the beginning
+        // of the selection is in an inserted text offset entry,
+        // the caret is always at the end of the entry!
+        selLength = 0;
+      } else {
+        selLength = entry->EndOffsetInTextInBlock() -
+                    mSelection.StartOffsetInTextInBlock();
+      }
+
+      if (selLength > 0) {
+        if (mSelection.StartOffsetInTextInBlock() >
+            entry->mOffsetInTextInBlock) {
+          // Selection doesn't start at the beginning of the
+          // text node entry. We need to split this entry into
+          // two pieces, the piece before the selection, and
+          // the piece inside the selection.
+          nsresult rv = SplitElementAt(i, selLength);
+          if (NS_FAILED(rv)) {
+            NS_WARNING("selLength was invalid for the OffsetEntry");
+            return rv;
+          }
+
+          // Adjust selection indexes to account for new entry:
+          MOZ_DIAGNOSTIC_ASSERT(mSelection.StartIndex() + 1 < Length());
+          MOZ_DIAGNOSTIC_ASSERT(mSelection.EndIndex() + 1 < Length());
+          mSelection.SetIndexes(mSelection.StartIndex() + 1,
+                                mSelection.EndIndex() + 1);
+          entry = ElementAt(++i).get();
+        }
+
+        if (mSelection.StartIndex() < mSelection.EndIndex()) {
+          // The entire entry is contained in the selection. Mark the
+          // entry invalid.
+          entry->mIsValid = false;
+        }
+      }
+    }
+
+    if (i == mSelection.EndIndex()) {
+      if (entry->mIsInsertedText) {
+        // Inserted text offset entries have no width when
+        // talking in terms of string offsets! If the end
+        // of the selection is in an inserted text offset entry,
+        // the selection includes the entire entry!
+        entry->mIsValid = false;
+      } else {
+        // Calculate the length of the selection. Note that the
+        // selection length can be zero if the end of the selection
+        // is at the very beginning of a text node entry.
+
+        const uint32_t selLength =
+            mSelection.EndOffsetInTextInBlock() - entry->mOffsetInTextInBlock;
+        if (selLength) {
+          if (mSelection.EndOffsetInTextInBlock() <
+              entry->EndOffsetInTextInBlock()) {
+            // mOffsetInTextInBlock is guaranteed to be inside the selection,
+            // even when mSelection.IsInSameElement() is true.
+            nsresult rv = SplitElementAt(i, entry->mLength - selLength);
+            if (NS_FAILED(rv)) {
+              NS_WARNING(
+                  "entry->mLength - selLength was invalid for the OffsetEntry");
+              return rv;
+            }
+
+            // Update the entry fields:
+            ElementAt(i + 1)->mOffsetInTextNode = entry->mOffsetInTextNode;
+          }
+
+          if (mSelection.EndOffsetInTextInBlock() ==
+              entry->EndOffsetInTextInBlock()) {
+            // The entire entry is contained in the selection. Mark the
+            // entry invalid.
+            entry->mIsValid = false;
+          }
+        }
+      }
+    }
+
+    if (i != mSelection.StartIndex() && i != mSelection.EndIndex()) {
+      // The entire entry is contained in the selection. Mark the
+      // entry invalid.
+      entry->mIsValid = false;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::DeleteSelection() {
+  if (NS_WARN_IF(!mEditorBase) ||
+      NS_WARN_IF(!mOffsetTable.mSelection.IsSet())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (mOffsetTable.mSelection.IsCollapsed()) {
+    return NS_OK;
+  }
+
+  // If we have an mExtent, save off its current set of
+  // end points so we can compare them against mExtent's
+  // set after the deletion of the content.
+
+  nsCOMPtr<nsINode> origStartNode, origEndNode;
+  uint32_t origStartOffset = 0, origEndOffset = 0;
+
+  if (mExtent) {
+    nsresult rv = GetRangeEndPoints(
+        mExtent, getter_AddRefs(origStartNode), &origStartOffset,
+        getter_AddRefs(origEndNode), &origEndOffset);
+
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  if (NS_FAILED(mOffsetTable.WillDeleteSelection())) {
+    NS_WARNING(
+        "TextServicesDocument::OffsetEntryTable::WillDeleteSelection() failed");
+    return NS_ERROR_FAILURE;
+  }
+
+  // Make sure mFilteredIter always points to something valid!
+  AdjustContentIterator();
+
+  // Now delete the actual content!
+  OwningNonNull<EditorBase> editorBase = *mEditorBase;
+  nsresult rv = editorBase->DeleteSelectionAsAction(nsIEditor::ePrevious,
+                                                    nsIEditor::eStrip);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // Now that we've actually deleted the selected content,
+  // check to see if our mExtent has changed, if so, then
+  // we have to create a new content iterator!
+
+  if (origStartNode && origEndNode) {
+    nsCOMPtr<nsINode> curStartNode, curEndNode;
+    uint32_t curStartOffset = 0, curEndOffset = 0;
+
+    rv = GetRangeEndPoints(mExtent, getter_AddRefs(curStartNode),
+                           &curStartOffset, getter_AddRefs(curEndNode),
+                           &curEndOffset);
+
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    if (origStartNode != curStartNode || origEndNode != curEndNode) {
+      // The range has changed, so we need to create a new content
+      // iterator based on the new range.
+      nsCOMPtr<nsIContent> curContent;
+      if (mIteratorStatus != IteratorStatus::eDone) {
+        // The old iterator is still pointing to something valid,
+        // so get its current node so we can restore it after we
+        // create the new iterator!
+        curContent = mFilteredIter->GetCurrentNode()
+                         ? mFilteredIter->GetCurrentNode()->AsContent()
+                         : nullptr;
+      }
+
+      // Create the new iterator.
+      rv =
+          CreateFilteredContentIterator(mExtent, getter_AddRefs(mFilteredIter));
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      // Now make the new iterator point to the content node
+      // the old one was pointing at.
+      if (curContent) {
+        rv = mFilteredIter->PositionAt(curContent);
+        if (NS_FAILED(rv)) {
+          mIteratorStatus = IteratorStatus::eDone;
+        } else {
+          mIteratorStatus = IteratorStatus::eValid;
+        }
+      }
+    }
+  }
+
+  OffsetEntry* entry = mOffsetTable.DidDeleteSelection();
+  if (entry) {
+    SetSelection(mOffsetTable.mSelection.StartOffsetInTextInBlock(), 0);
+  }
+
+  // Now remove any invalid entries from the offset table.
+  mOffsetTable.RemoveInvalidElements();
+  return NS_OK;
+}
+
+OffsetEntry* TextServicesDocument::OffsetEntryArray::DidDeleteSelection() {
+  MOZ_ASSERT(mSelection.IsSet());
+
+  // Move the caret to the end of the first valid entry.
+  // Start with SelectionStartIndex() since it may still be valid.
+  OffsetEntry* entry = nullptr;
+  for (size_t i = mSelection.StartIndex() + 1; !entry && i > 0; i--) {
+    entry = ElementAt(i - 1).get();
+    if (!entry->mIsValid) {
+      entry = nullptr;
+    } else {
+      MOZ_DIAGNOSTIC_ASSERT(i - 1 < Length());
+      mSelection.Set(i - 1, entry->EndOffsetInTextInBlock());
+    }
+  }
+
+  // If we still don't have a valid entry, move the caret
+  // to the next valid entry after the selection:
+  for (size_t i = mSelection.EndIndex(); !entry && i < Length(); i++) {
+    entry = ElementAt(i).get();
+    if (!entry->mIsValid) {
+      entry = nullptr;
+    } else {
+      MOZ_DIAGNOSTIC_ASSERT(i < Length());
+      mSelection.Set(i, entry->mOffsetInTextInBlock);
+    }
+  }
+
+  if (!entry) {
+    // Uuughh we have no valid offset entry to place our
+    // caret ... just mark the selection invalid.
+    mSelection.Reset();
+  }
+
+  return entry;
+}
+
+nsresult TextServicesDocument::InsertText(const nsAString& aText) {
+  if (NS_WARN_IF(!mEditorBase) ||
+      NS_WARN_IF(!mOffsetTable.mSelection.IsSet())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // If the selection is not collapsed, we need to save
+  // off the selection offsets so we can restore the
+  // selection and delete the selected content after we've
+  // inserted the new text. This is necessary to try and
+  // retain as much of the original style of the content
+  // being deleted.
+
+  const bool wasSelectionCollapsed = mOffsetTable.mSelection.IsCollapsed();
+  const uint32_t savedSelOffset =
+      mOffsetTable.mSelection.StartOffsetInTextInBlock();
+  const uint32_t savedSelLength = mOffsetTable.mSelection.LengthInTextInBlock();
+
+  if (!wasSelectionCollapsed) {
+    // Collapse to the start of the current selection
+    // for the insert!
+    nsresult rv =
+        SetSelection(mOffsetTable.mSelection.StartOffsetInTextInBlock(), 0);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // AutoTransactionBatchExternal grabs mEditorBase, so, we don't need to grab
+  // the instance with local variable here.
+  OwningNonNull<EditorBase> editorBase = *mEditorBase;
+  AutoTransactionBatchExternal treatAsOneTransaction(editorBase);
+
+  nsresult rv = editorBase->InsertTextAsAction(aText);
+  if (NS_FAILED(rv)) {
+    NS_WARNING("InsertTextAsAction() failed");
+    return rv;
+  }
+
+  RefPtr<Selection> selection =
+      mSelCon->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  rv = mOffsetTable.DidInsertText(selection, aText);
+  if (NS_FAILED(rv)) {
+    NS_WARNING("TextServicesDocument::OffsetEntry::DidInsertText() failed");
+    return rv;
+  }
+
+  if (!wasSelectionCollapsed) {
+    nsresult rv = SetSelection(savedSelOffset, savedSelLength);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    rv = DeleteSelection();
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::OffsetEntryArray::DidInsertText(
+    dom::Selection* aSelection, const nsAString& aInsertedString) {
+  MOZ_ASSERT(mSelection.IsSet());
+
+  // When you touch this method, please make sure that the entry instance
+  // won't be deleted.  If you know it'll be deleted, you should set it to
+  // `nullptr`.
+  OffsetEntry* entry = ElementAt(mSelection.StartIndex()).get();
+  OwningNonNull<Text> const textNodeAtStartEntry = entry->mTextNode;
+
+  NS_ASSERTION((entry->mIsValid), "Invalid insertion point!");
+
+  if (entry->mOffsetInTextInBlock == mSelection.StartOffsetInTextInBlock()) {
+    if (entry->mIsInsertedText) {
+      // If the caret is in an inserted text offset entry,
+      // we simply insert the text at the end of the entry.
+      entry->mLength += aInsertedString.Length();
+    } else {
+      // Insert an inserted text offset entry before the current
+      // entry!
+      UniquePtr<OffsetEntry> newInsertedTextEntry =
+          MakeUnique<OffsetEntry>(entry->mTextNode, entry->mOffsetInTextInBlock,
+                                  aInsertedString.Length());
+      newInsertedTextEntry->mIsInsertedText = true;
+      newInsertedTextEntry->mOffsetInTextNode = entry->mOffsetInTextNode;
+      // XXX(Bug 1631371) Check if this should use a fallible operation as it
+      // pretended earlier.
+      InsertElementAt(mSelection.StartIndex(), std::move(newInsertedTextEntry));
+    }
+  } else if (entry->EndOffsetInTextInBlock() ==
+             mSelection.EndOffsetInTextInBlock()) {
+    // We are inserting text at the end of the current offset entry.
+    // Look at the next valid entry in the table. If it's an inserted
+    // text entry, add to its length and adjust its node offset. If
+    // it isn't, add a new inserted text entry.
+    uint32_t nextIndex = mSelection.StartIndex() + 1;
+    OffsetEntry* insertedTextEntry = nullptr;
+    if (Length() > nextIndex) {
+      insertedTextEntry = ElementAt(nextIndex).get();
+      if (!insertedTextEntry) {
+        return NS_ERROR_FAILURE;
+      }
+
+      // Check if the entry is a match. If it isn't, set
+      // iEntry to zero.
+      if (!insertedTextEntry->mIsInsertedText ||
+          insertedTextEntry->mOffsetInTextInBlock !=
+              mSelection.StartOffsetInTextInBlock()) {
+        insertedTextEntry = nullptr;
+      }
+    }
+
+    if (!insertedTextEntry) {
+      // We didn't find an inserted text offset entry, so
+      // create one.
+      UniquePtr<OffsetEntry> newInsertedTextEntry = MakeUnique<OffsetEntry>(
+          entry->mTextNode, mSelection.StartOffsetInTextInBlock(), 0);
+      newInsertedTextEntry->mOffsetInTextNode = entry->EndOffsetInTextNode();
+      newInsertedTextEntry->mIsInsertedText = true;
+      // XXX(Bug 1631371) Check if this should use a fallible operation as it
+      // pretended earlier.
+      insertedTextEntry =
+          InsertElementAt(nextIndex, std::move(newInsertedTextEntry))->get();
+    }
+
+    // We have a valid inserted text offset entry. Update its
+    // length, adjust the selection indexes, and make sure the
+    // caret is properly placed!
+
+    insertedTextEntry->mLength += aInsertedString.Length();
+
+    MOZ_DIAGNOSTIC_ASSERT(nextIndex < Length());
+    mSelection.SetIndex(nextIndex);
+
+    if (!aSelection) {
+      return NS_OK;
+    }
+
+    OwningNonNull<Text> textNode = insertedTextEntry->mTextNode;
+    nsresult rv = aSelection->CollapseInLimiter(
+        textNode, insertedTextEntry->EndOffsetInTextNode());
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Selection::CollapseInLimiter() failed");
+      return rv;
+    }
+  } else if (entry->EndOffsetInTextInBlock() >
+             mSelection.StartOffsetInTextInBlock()) {
+    // We are inserting text into the middle of the current offset entry.
+    // split the current entry into two parts, then insert an inserted text
+    // entry between them!
+    nsresult rv = SplitElementAt(mSelection.StartIndex(),
+                                 entry->EndOffsetInTextInBlock() -
+                                     mSelection.StartOffsetInTextInBlock());
+    if (NS_FAILED(rv)) {
+      NS_WARNING(
+          "entry->EndOffsetInTextInBlock() - "
+          "mSelection.StartOffsetInTextInBlock() was invalid for the "
+          "OffsetEntry");
+      return rv;
+    }
+
+    // XXX(Bug 1631371) Check if this should use a fallible operation as it
+    // pretended earlier.
+    UniquePtr<OffsetEntry>& insertedTextEntry = *InsertElementAt(
+        mSelection.StartIndex() + 1,
+        MakeUnique<OffsetEntry>(entry->mTextNode,
+                                mSelection.StartOffsetInTextInBlock(),
+                                aInsertedString.Length()));
+    LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+    insertedTextEntry->mIsInsertedText = true;
+    insertedTextEntry->mOffsetInTextNode = entry->EndOffsetInTextNode();
+    MOZ_DIAGNOSTIC_ASSERT(mSelection.StartIndex() + 1 < Length());
+    mSelection.SetIndex(mSelection.StartIndex() + 1);
+  }
+
+  // We've just finished inserting an inserted text offset entry.
+  // update all entries with the same mTextNode pointer that follow
+  // it in the table!
+
+  for (size_t i = mSelection.StartIndex() + 1; i < Length(); i++) {
+    const UniquePtr<OffsetEntry>& entry = ElementAt(i);
+    LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+    if (entry->mTextNode != textNodeAtStartEntry) {
+      break;
+    }
+    if (entry->mIsValid) {
+      entry->mOffsetInTextNode += aInsertedString.Length();
+    }
+  }
+
+  return NS_OK;
+}
+
+void TextServicesDocument::DidDeleteContent(const nsIContent& aChildContent) {
+  if (NS_WARN_IF(!mFilteredIter) || !aChildContent.IsText()) {
+    return;
+  }
+
+  Maybe<size_t> maybeNodeIndex =
+      mOffsetTable.FirstIndexOf(*aChildContent.AsText());
+  if (maybeNodeIndex.isNothing()) {
+    // It's okay if the node isn't in the offset table, the
+    // editor could be cleaning house.
+    return;
+  }
+
+  nsINode* node = mFilteredIter->GetCurrentNode();
+  if (node && node == &aChildContent &&
+      mIteratorStatus != IteratorStatus::eDone) {
+    // XXX: This should never really happen because
+    // AdjustContentIterator() should have been called prior
+    // to the delete to try and position the iterator on the
+    // next valid text node in the offset table, and if there
+    // wasn't a next, it would've set mIteratorStatus to eIsDone.
+
+    NS_ERROR("DeleteNode called for current iterator node.");
+  }
+
+  for (size_t nodeIndex = *maybeNodeIndex; nodeIndex < mOffsetTable.Length();
+       nodeIndex++) {
+    const UniquePtr<OffsetEntry>& entry = mOffsetTable[nodeIndex];
+    LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+    if (!entry) {
+      return;
+    }
+
+    if (entry->mTextNode == &aChildContent) {
+      entry->mIsValid = false;
+    }
+  }
+}
+
+void TextServicesDocument::DidJoinContents(
+    const EditorRawDOMPoint& aJoinedPoint, const nsIContent& aRemovedContent) {
+  // Make sure that both nodes are text nodes -- otherwise we don't care.
+  if (!aJoinedPoint.IsInTextNode() || !aRemovedContent.IsText()) {
+    return;
+  }
+
+  // Note: The editor merges the contents of the left node into the
+  //       contents of the right.
+
+  Maybe<size_t> maybeRemovedIndex =
+      mOffsetTable.FirstIndexOf(*aRemovedContent.AsText());
+  if (maybeRemovedIndex.isNothing()) {
+    // It's okay if the node isn't in the offset table, the
+    // editor could be cleaning house.
+    return;
+  }
+
+  Maybe<size_t> maybeJoinedIndex =
+      mOffsetTable.FirstIndexOf(*aJoinedPoint.ContainerAs<Text>());
+  if (maybeJoinedIndex.isNothing()) {
+    // It's okay if the node isn't in the offset table, the
+    // editor could be cleaning house.
+    return;
+  }
+
+  const size_t removedIndex = *maybeRemovedIndex;
+  const size_t joinedIndex = *maybeJoinedIndex;
+
+  if (MOZ_UNLIKELY(joinedIndex > removedIndex)) {
+    NS_ASSERTION(joinedIndex < removedIndex, "Indexes out of order.");
+    return;
+  }
+  NS_ASSERTION(mOffsetTable[removedIndex]->mOffsetInTextNode == 0,
+               "Unexpected offset value for rightIndex.");
+
+  // Run through the table and change all entries referring to
+  // the removed node so that they now refer to the joined node,
+  // and adjust offsets if necessary.
+  const uint32_t movedTextDataLength =
+      aJoinedPoint.ContainerAs<Text>()->TextDataLength() -
+      aJoinedPoint.Offset();
+  for (uint32_t i = removedIndex; i < mOffsetTable.Length(); i++) {
+    const UniquePtr<OffsetEntry>& entry = mOffsetTable[i];
+    LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+    if (entry->mTextNode != aRemovedContent.AsText()) {
+      break;
+    }
+    if (entry->mIsValid) {
+      entry->mTextNode = aJoinedPoint.ContainerAs<Text>();
+      // The text was moved from aRemovedContent to end of the container of
+      // aJoinedPoint.
+      entry->mOffsetInTextNode += movedTextDataLength;
+    }
+  }
+
+  // Now check to see if the iterator is pointing to the
+  // left node. If it is, make it point to the joined node!
+  if (mFilteredIter->GetCurrentNode() == aRemovedContent.AsText()) {
+    mFilteredIter->PositionAt(aJoinedPoint.ContainerAs<Text>());
+  }
+}
+
+nsresult TextServicesDocument::CreateFilteredContentIterator(
+    const AbstractRange* aAbstractRange,
+    FilteredContentIterator** aFilteredIter) {
+  if (NS_WARN_IF(!aAbstractRange) || NS_WARN_IF(!aFilteredIter)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  *aFilteredIter = nullptr;
+
+  UniquePtr<nsComposeTxtSrvFilter> composeFilter;
+  switch (mTxtSvcFilterType) {
+    case nsIEditorSpellCheck::FILTERTYPE_NORMAL:
+      composeFilter = nsComposeTxtSrvFilter::CreateNormalFilter();
+      break;
+    case nsIEditorSpellCheck::FILTERTYPE_MAIL:
+      composeFilter = nsComposeTxtSrvFilter::CreateMailFilter();
+      break;
+  }
+
+  // Create a FilteredContentIterator
+  // This class wraps the ContentIterator in order to give itself a chance
+  // to filter out certain content nodes
+  RefPtr<FilteredContentIterator> filter =
+      new FilteredContentIterator(std::move(composeFilter));
+  nsresult rv = filter->Init(aAbstractRange);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  filter.forget(aFilteredIter);
+  return NS_OK;
+}
+
+Element* TextServicesDocument::GetDocumentContentRootNode() const {
+  if (NS_WARN_IF(!mDocument)) {
+    return nullptr;
+  }
+
+  if (mDocument->IsHTMLOrXHTML()) {
+    Element* rootElement = mDocument->GetRootElement();
+    if (rootElement && rootElement->IsXULElement()) {
+      // HTML documents with root XUL elements should eventually be transitioned
+      // to a regular document structure, but for now the content root node will
+      // be the document element.
+      return mDocument->GetDocumentElement();
+    }
+    // For HTML documents, the content root node is the body.
+    return mDocument->GetBody();
+  }
+
+  // For non-HTML documents, the content root node will be the document element.
+  return mDocument->GetDocumentElement();
+}
+
+already_AddRefed<nsRange> TextServicesDocument::CreateDocumentContentRange() {
+  nsCOMPtr<nsINode> node = GetDocumentContentRootNode();
+  if (NS_WARN_IF(!node)) {
+    return nullptr;
+  }
+
+  RefPtr<nsRange> range = nsRange::Create(node);
+  IgnoredErrorResult ignoredError;
+  range->SelectNodeContents(*node, ignoredError);
+  NS_WARNING_ASSERTION(!ignoredError.Failed(), "SelectNodeContents() failed");
+  return range.forget();
+}
+
+already_AddRefed<nsRange>
+TextServicesDocument::CreateDocumentContentRootToNodeOffsetRange(
+    nsINode* aParent, uint32_t aOffset, bool aToStart) {
+  if (NS_WARN_IF(!aParent)) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsINode> bodyNode = GetDocumentContentRootNode();
+  if (NS_WARN_IF(!bodyNode)) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsINode> startNode;
+  nsCOMPtr<nsINode> endNode;
+  uint32_t startOffset, endOffset;
+
+  if (aToStart) {
+    // The range should begin at the start of the document
+    // and extend up until (aParent, aOffset).
+    startNode = bodyNode;
+    startOffset = 0;
+    endNode = aParent;
+    endOffset = aOffset;
+  } else {
+    // The range should begin at (aParent, aOffset) and
+    // extend to the end of the document.
+    startNode = aParent;
+    startOffset = aOffset;
+    endNode = bodyNode;
+    endOffset = endNode ? endNode->GetChildCount() : 0;
+  }
+
+  RefPtr<nsRange> range = nsRange::Create(startNode, startOffset, endNode,
+                                          endOffset, IgnoreErrors());
+  NS_WARNING_ASSERTION(range,
+                       "nsRange::Create() failed to create new valid range");
+  return range.forget();
+}
+
+nsresult TextServicesDocument::CreateDocumentContentIterator(
+    FilteredContentIterator** aFilteredIter) {
+  NS_ENSURE_TRUE(aFilteredIter, NS_ERROR_NULL_POINTER);
+
+  RefPtr<nsRange> range = CreateDocumentContentRange();
+  if (NS_WARN_IF(!range)) {
+    *aFilteredIter = nullptr;
+    return NS_ERROR_FAILURE;
+  }
+
+  return CreateFilteredContentIterator(range, aFilteredIter);
+}
+
+nsresult TextServicesDocument::AdjustContentIterator() {
+  NS_ENSURE_TRUE(mFilteredIter, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsINode> node = mFilteredIter->GetCurrentNode();
+  NS_ENSURE_TRUE(node, NS_ERROR_FAILURE);
+
+  Text* prevValidTextNode = nullptr;
+  Text* nextValidTextNode = nullptr;
+  bool foundEntry = false;
+
+  const size_t tableLength = mOffsetTable.Length();
+  for (size_t i = 0; i < tableLength && !nextValidTextNode; i++) {
+    UniquePtr<OffsetEntry>& entry = mOffsetTable[i];
+    LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+    if (entry->mTextNode == node) {
+      if (entry->mIsValid) {
+        // The iterator is still pointing to something valid!
+        // Do nothing!
+        return NS_OK;
+      }
+      // We found an invalid entry that points to
+      // the current iterator node. Stop looking for
+      // a previous valid node!
+      foundEntry = true;
+    }
+
+    if (entry->mIsValid) {
+      if (!foundEntry) {
+        prevValidTextNode = entry->mTextNode;
+      } else {
+        nextValidTextNode = entry->mTextNode;
+      }
+    }
+  }
+
+  Text* validTextNode = nullptr;
+  if (prevValidTextNode) {
+    validTextNode = prevValidTextNode;
+  } else if (nextValidTextNode) {
+    validTextNode = nextValidTextNode;
+  }
+
+  if (validTextNode) {
+    nsresult rv = mFilteredIter->PositionAt(validTextNode);
+    if (NS_FAILED(rv)) {
+      mIteratorStatus = IteratorStatus::eDone;
+    } else {
+      mIteratorStatus = IteratorStatus::eValid;
+    }
+    return rv;
+  }
+
+  // If we get here, there aren't any valid entries
+  // in the offset table! Try to position the iterator
+  // on the next text block first, then previous if
+  // one doesn't exist!
+
+  if (mNextTextBlock) {
+    nsresult rv = mFilteredIter->PositionAt(mNextTextBlock);
+    if (NS_FAILED(rv)) {
+      mIteratorStatus = IteratorStatus::eDone;
+      return rv;
+    }
+
+    mIteratorStatus = IteratorStatus::eNext;
+  } else if (mPrevTextBlock) {
+    nsresult rv = mFilteredIter->PositionAt(mPrevTextBlock);
+    if (NS_FAILED(rv)) {
+      mIteratorStatus = IteratorStatus::eDone;
+      return rv;
+    }
+
+    mIteratorStatus = IteratorStatus::ePrev;
+  } else {
+    mIteratorStatus = IteratorStatus::eDone;
+  }
+  return NS_OK;
+}
+
+// static
+bool TextServicesDocument::DidSkip(FilteredContentIterator* aFilteredIter) {
+  return aFilteredIter && aFilteredIter->DidSkip();
+}
+
+// static
+void TextServicesDocument::ClearDidSkip(
+    FilteredContentIterator* aFilteredIter) {
+  // Clear filter's skip flag
+  if (aFilteredIter) {
+    aFilteredIter->ClearDidSkip();
+  }
+}
+
+// static
+bool TextServicesDocument::HasSameBlockNodeParent(Text& aTextNode1,
+                                                  Text& aTextNode2) {
+  // XXX How about the case that both text nodes are orphan nodes?
+  if (aTextNode1.GetParent() == aTextNode2.GetParent()) {
+    return true;
+  }
+
+  // I think that spellcheck should be available only in editable nodes.
+  // So, we also need to check whether they are in same editing host.
+  const Element* editableBlockElementOrInlineEditingHost1 =
+      HTMLEditUtils::GetAncestorElement(
+          aTextNode1,
+          HTMLEditUtils::ClosestEditableBlockElementOrInlineEditingHost,
+          BlockInlineCheck::UseHTMLDefaultStyle);
+  const Element* editableBlockElementOrInlineEditingHost2 =
+      HTMLEditUtils::GetAncestorElement(
+          aTextNode2,
+          HTMLEditUtils::ClosestEditableBlockElementOrInlineEditingHost,
+          BlockInlineCheck::UseHTMLDefaultStyle);
+  return editableBlockElementOrInlineEditingHost1 &&
+         editableBlockElementOrInlineEditingHost1 ==
+             editableBlockElementOrInlineEditingHost2;
+}
+
+Result<EditorRawDOMRangeInTexts, nsresult>
+TextServicesDocument::OffsetEntryArray::WillSetSelection(
+    uint32_t aOffsetInTextInBlock, uint32_t aLength) {
+  // Find start of selection in node offset terms:
+  EditorRawDOMPointInText newStart;
+  for (size_t i = 0; !newStart.IsSet() && i < Length(); i++) {
+    const UniquePtr<OffsetEntry>& entry = ElementAt(i);
+    LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+    if (entry->mIsValid) {
+      if (entry->mIsInsertedText) {
+        // Caret can only be placed at the end of an
+        // inserted text offset entry, if the offsets
+        // match exactly!
+        if (entry->mOffsetInTextInBlock == aOffsetInTextInBlock) {
+          newStart.Set(entry->mTextNode, entry->EndOffsetInTextNode());
+        }
+      } else if (aOffsetInTextInBlock >= entry->mOffsetInTextInBlock) {
+        bool foundEntry = false;
+        if (aOffsetInTextInBlock < entry->EndOffsetInTextInBlock()) {
+          foundEntry = true;
+        } else if (aOffsetInTextInBlock == entry->EndOffsetInTextInBlock()) {
+          // Peek after this entry to see if we have any
+          // inserted text entries belonging to the same
+          // entry->mTextNode. If so, we have to place the selection
+          // after it!
+          if (i + 1 < Length()) {
+            const UniquePtr<OffsetEntry>& nextEntry = ElementAt(i + 1);
+            LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+            if (!nextEntry->mIsValid ||
+                nextEntry->mOffsetInTextInBlock != aOffsetInTextInBlock) {
+              // Next offset entry isn't an exact match, so we'll
+              // just use the current entry.
+              foundEntry = true;
+            }
+          }
+        }
+
+        if (foundEntry) {
+          newStart.Set(entry->mTextNode, entry->mOffsetInTextNode +
+                                             aOffsetInTextInBlock -
+                                             entry->mOffsetInTextInBlock);
+        }
+      }
+
+      if (newStart.IsSet()) {
+        MOZ_DIAGNOSTIC_ASSERT(i < Length());
+        mSelection.Set(i, aOffsetInTextInBlock);
+      }
+    }
+  }
+
+  if (NS_WARN_IF(!newStart.IsSet())) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  if (!aLength) {
+    mSelection.CollapseToStart();
+    return EditorRawDOMRangeInTexts(newStart);
+  }
+
+  // Find the end of the selection in node offset terms:
+  EditorRawDOMPointInText newEnd;
+  const uint32_t endOffset = aOffsetInTextInBlock + aLength;
+  for (uint32_t i = Length(); !newEnd.IsSet() && i > 0; i--) {
+    const UniquePtr<OffsetEntry>& entry = ElementAt(i - 1);
+    LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+    if (entry->mIsValid) {
+      if (entry->mIsInsertedText) {
+        if (entry->mOffsetInTextInBlock ==
+            (newEnd.IsSet() ? newEnd.Offset() : 0)) {
+          // If the selection ends on an inserted text offset entry,
+          // the selection includes the entire entry!
+          newEnd.Set(entry->mTextNode, entry->EndOffsetInTextNode());
+        }
+      } else if (entry->OffsetInTextInBlockIsInRangeOrEndOffset(endOffset)) {
+        newEnd.Set(entry->mTextNode, entry->mOffsetInTextNode + endOffset -
+                                         entry->mOffsetInTextInBlock);
+      }
+
+      if (newEnd.IsSet()) {
+        MOZ_DIAGNOSTIC_ASSERT(mSelection.StartIndex() < Length());
+        MOZ_DIAGNOSTIC_ASSERT(i - 1 < Length());
+        mSelection.Set(mSelection.StartIndex(), i - 1,
+                       mSelection.StartOffsetInTextInBlock(), endOffset);
+      }
+    }
+  }
+
+  return newEnd.IsSet() ? EditorRawDOMRangeInTexts(newStart, newEnd)
+                        : EditorRawDOMRangeInTexts(newStart);
+}
+
+nsresult TextServicesDocument::SetSelectionInternal(
+    uint32_t aOffsetInTextInBlock, uint32_t aLength, bool aDoUpdate) {
+  if (NS_WARN_IF(!mSelCon)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  Result<EditorRawDOMRangeInTexts, nsresult> newSelectionRange =
+      mOffsetTable.WillSetSelection(aOffsetInTextInBlock, aLength);
+  if (newSelectionRange.isErr()) {
+    NS_WARNING(
+        "TextServicesDocument::OffsetEntryArray::WillSetSelection() failed");
+    return newSelectionRange.unwrapErr();
+  }
+
+  if (!aDoUpdate) {
+    return NS_OK;
+  }
+
+  // XXX: If we ever get a SetSelection() method in nsIEditor, we should
+  //      use it.
+  RefPtr<Selection> selection =
+      mSelCon->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  if (NS_WARN_IF(!selection)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (newSelectionRange.inspect().Collapsed()) {
+    nsresult rv =
+        selection->CollapseInLimiter(newSelectionRange.inspect().StartRef());
+    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
+                         "Selection::CollapseInLimiter() failed");
+    return rv;
+  }
+
+  ErrorResult error;
+  selection->SetStartAndEndInLimiter(newSelectionRange.inspect().StartRef(),
+                                     newSelectionRange.inspect().EndRef(),
+                                     error);
+  NS_WARNING_ASSERTION(!error.Failed(),
+                       "Selection::SetStartAndEndInLimiter() failed");
+  return error.StealNSResult();
+}
+
+nsresult TextServicesDocument::GetSelection(BlockSelectionStatus* aSelStatus,
+                                            uint32_t* aSelOffset,
+                                            uint32_t* aSelLength) {
+  NS_ENSURE_TRUE(aSelStatus && aSelOffset && aSelLength, NS_ERROR_NULL_POINTER);
+
+  *aSelStatus = BlockSelectionStatus::eBlockNotFound;
+  *aSelOffset = UINT32_MAX;
+  *aSelLength = UINT32_MAX;
+
+  NS_ENSURE_TRUE(mDocument && mSelCon, NS_ERROR_FAILURE);
+
+  if (mIteratorStatus == IteratorStatus::eDone) {
+    return NS_OK;
+  }
+
+  RefPtr<Selection> selection =
+      mSelCon->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  NS_ENSURE_TRUE(selection, NS_ERROR_FAILURE);
+
+  if (selection->IsCollapsed()) {
+    return GetCollapsedSelection(aSelStatus, aSelOffset, aSelLength);
+  }
+
+  return GetUncollapsedSelection(aSelStatus, aSelOffset, aSelLength);
+}
+
+nsresult TextServicesDocument::GetCollapsedSelection(
+    BlockSelectionStatus* aSelStatus, uint32_t* aSelOffset,
+    uint32_t* aSelLength) {
+  RefPtr<Selection> selection =
+      mSelCon->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  NS_ENSURE_TRUE(selection, NS_ERROR_FAILURE);
+
+  // The calling function should have done the GetIsCollapsed()
+  // check already. Just assume it's collapsed!
+  *aSelStatus = BlockSelectionStatus::eBlockOutside;
+  *aSelOffset = *aSelLength = UINT32_MAX;
+
+  const uint32_t tableCount = mOffsetTable.Length();
+  if (!tableCount) {
+    return NS_OK;
+  }
+
+  // Get pointers to the first and last offset entries
+  // in the table.
+
+  UniquePtr<OffsetEntry>& eStart = mOffsetTable[0];
+  UniquePtr<OffsetEntry>& eEnd =
+      tableCount > 1 ? mOffsetTable[tableCount - 1] : eStart;
+  LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+
+  const uint32_t eStartOffset = eStart->mOffsetInTextNode;
+  const uint32_t eEndOffset = eEnd->EndOffsetInTextNode();
+
+  RefPtr<const nsRange> range = selection->GetRangeAt(0);
+  NS_ENSURE_STATE(range);
+
+  nsCOMPtr<nsINode> parent = range->GetStartContainer();
+  MOZ_ASSERT(parent);
+
+  uint32_t offset = range->StartOffset();
+
+  const Maybe<int32_t> e1s1 = nsContentUtils::ComparePoints(
+      eStart->mTextNode, eStartOffset, parent, offset);
+  const Maybe<int32_t> e2s1 = nsContentUtils::ComparePoints(
+      eEnd->mTextNode, eEndOffset, parent, offset);
+
+  if (MOZ_UNLIKELY(NS_WARN_IF(!e1s1) || NS_WARN_IF(!e2s1))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (*e1s1 > 0 || *e2s1 < 0) {
+    // We're done if the caret is outside the current text block.
+    return NS_OK;
+  }
+
+  if (parent->IsText()) {
+    // Good news, the caret is in a text node. Look
+    // through the offset table for the entry that
+    // matches its parent and offset.
+
+    for (uint32_t i = 0; i < tableCount; i++) {
+      const UniquePtr<OffsetEntry>& entry = mOffsetTable[i];
+      LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+      if (entry->mTextNode == parent->AsText() &&
+          entry->OffsetInTextNodeIsInRangeOrEndOffset(offset)) {
+        *aSelStatus = BlockSelectionStatus::eBlockContains;
+        *aSelOffset =
+            entry->mOffsetInTextInBlock + (offset - entry->mOffsetInTextNode);
+        *aSelLength = 0;
+        return NS_OK;
+      }
+    }
+
+    // If we get here, we didn't find a text node entry
+    // in our offset table that matched.
+    return NS_ERROR_FAILURE;
+  }
+
+  // The caret is in our text block, but it's positioned in some
+  // non-text node (ex. <b>). Create a range based on the start
+  // and end of the text block, then create an iterator based on
+  // this range, with its initial position set to the closest
+  // child of this non-text node. Then look for the closest text
+  // node.
+
+  range = nsRange::Create(eStart->mTextNode, eStartOffset, eEnd->mTextNode,
+                          eEndOffset, IgnoreErrors());
+  if (NS_WARN_IF(!range)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<FilteredContentIterator> filteredIter;
+  nsresult rv =
+      CreateFilteredContentIterator(range, getter_AddRefs(filteredIter));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsIContent* saveNode;
+  if (parent->HasChildren()) {
+    // XXX: We need to make sure that all of parent's
+    //      children are in the text block.
+
+    // If the parent has children, position the iterator
+    // on the child that is to the left of the offset.
+
+    nsIContent* content = range->GetChildAtStartOffset();
+    if (content && parent->GetFirstChild() != content) {
+      content = content->GetPreviousSibling();
+    }
+    NS_ENSURE_TRUE(content, NS_ERROR_FAILURE);
+
+    nsresult rv = filteredIter->PositionAt(content);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    saveNode = content;
+  } else {
+    // The parent has no children, so position the iterator
+    // on the parent.
+    NS_ENSURE_TRUE(parent->IsContent(), NS_ERROR_FAILURE);
+    nsCOMPtr<nsIContent> content = parent->AsContent();
+
+    nsresult rv = filteredIter->PositionAt(content);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    saveNode = content;
+  }
+
+  // Now iterate to the left, towards the beginning of
+  // the text block, to find the first text node you
+  // come across.
+
+  Text* textNode = nullptr;
+  for (; !filteredIter->IsDone(); filteredIter->Prev()) {
+    nsINode* current = filteredIter->GetCurrentNode();
+    if (current->IsText()) {
+      textNode = current->AsText();
+      break;
+    }
+  }
+
+  if (textNode) {
+    // We found a node, now set the offset to the end
+    // of the text node.
+    offset = textNode->TextLength();
+  } else {
+    // We should never really get here, but I'm paranoid.
+
+    // We didn't find a text node above, so iterate to
+    // the right, towards the end of the text block, looking
+    // for a text node.
+
+    nsresult rv = filteredIter->PositionAt(saveNode);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    textNode = nullptr;
+    for (; !filteredIter->IsDone(); filteredIter->Next()) {
+      nsINode* current = filteredIter->GetCurrentNode();
+      if (current->IsText()) {
+        textNode = current->AsText();
+        break;
+      }
+    }
+    NS_ENSURE_TRUE(textNode, NS_ERROR_FAILURE);
+
+    // We found a text node, so set the offset to
+    // the beginning of the node.
+    offset = 0;
+  }
+
+  for (size_t i = 0; i < tableCount; i++) {
+    const UniquePtr<OffsetEntry>& entry = mOffsetTable[i];
+    LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+    if (entry->mTextNode == textNode &&
+        entry->OffsetInTextNodeIsInRangeOrEndOffset(offset)) {
+      *aSelStatus = BlockSelectionStatus::eBlockContains;
+      *aSelOffset =
+          entry->mOffsetInTextInBlock + (offset - entry->mOffsetInTextNode);
+      *aSelLength = 0;
+
+      // Now move the caret so that it is actually in the text node.
+      // We do this to keep things in sync.
+      //
+      // In most cases, the user shouldn't see any movement in the caret
+      // on screen.
+      return SetSelectionInternal(*aSelOffset, *aSelLength, true);
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+nsresult TextServicesDocument::GetUncollapsedSelection(
+    BlockSelectionStatus* aSelStatus, uint32_t* aSelOffset,
+    uint32_t* aSelLength) {
+  RefPtr<const nsRange> range;
+  RefPtr<Selection> selection =
+      mSelCon->GetSelection(nsISelectionController::SELECTION_NORMAL);
+  NS_ENSURE_TRUE(selection, NS_ERROR_FAILURE);
+
+  // It is assumed that the calling function has made sure that the
+  // selection is not collapsed, and that the input params to this
+  // method are initialized to some defaults.
+
+  nsCOMPtr<nsINode> startContainer, endContainer;
+
+  const size_t tableCount = mOffsetTable.Length();
+
+  // Get pointers to the first and last offset entries
+  // in the table.
+
+  UniquePtr<OffsetEntry>& eStart = mOffsetTable[0];
+  UniquePtr<OffsetEntry>& eEnd =
+      tableCount > 1 ? mOffsetTable[tableCount - 1] : eStart;
+  LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+
+  const uint32_t eStartOffset = eStart->mOffsetInTextNode;
+  const uint32_t eEndOffset = eEnd->EndOffsetInTextNode();
+
+  const uint32_t rangeCount = selection->RangeCount();
+  MOZ_ASSERT(rangeCount);
+
+  // Find the first range in the selection that intersects
+  // the current text block.
+  Maybe<int32_t> e1s2;
+  Maybe<int32_t> e2s1;
+  uint32_t startOffset, endOffset;
+  for (const uint32_t i : IntegerRange(rangeCount)) {
+    MOZ_ASSERT(selection->RangeCount() == rangeCount);
+    range = selection->GetRangeAt(i);
+    if (MOZ_UNLIKELY(NS_WARN_IF(!range))) {
+      return NS_ERROR_FAILURE;
+    }
+
+    nsresult rv =
+        GetRangeEndPoints(range, getter_AddRefs(startContainer), &startOffset,
+                          getter_AddRefs(endContainer), &endOffset);
+
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    e1s2 = nsContentUtils::ComparePoints(eStart->mTextNode, eStartOffset,
+                                         endContainer, endOffset);
+    if (NS_WARN_IF(!e1s2)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    e2s1 = nsContentUtils::ComparePoints(eEnd->mTextNode, eEndOffset,
+                                         startContainer, startOffset);
+    if (NS_WARN_IF(!e2s1)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    // Break out of the loop if the text block intersects the current range.
+
+    if (*e1s2 <= 0 && *e2s1 >= 0) {
+      break;
+    }
+  }
+
+  // We're done if we didn't find an intersecting range.
+
+  if (rangeCount < 1 || *e1s2 > 0 || *e2s1 < 0) {
+    *aSelStatus = BlockSelectionStatus::eBlockOutside;
+    *aSelOffset = *aSelLength = UINT32_MAX;
+    return NS_OK;
+  }
+
+  // Now that we have an intersecting range, find out more info:
+  const Maybe<int32_t> e1s1 = nsContentUtils::ComparePoints(
+      eStart->mTextNode, eStartOffset, startContainer, startOffset);
+  if (NS_WARN_IF(!e1s1)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  const Maybe<int32_t> e2s2 = nsContentUtils::ComparePoints(
+      eEnd->mTextNode, eEndOffset, endContainer, endOffset);
+  if (NS_WARN_IF(!e2s2)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (rangeCount > 1) {
+    // There are multiple selection ranges, we only deal
+    // with the first one that intersects the current,
+    // text block, so mark this a as a partial.
+    *aSelStatus = BlockSelectionStatus::eBlockPartial;
+  } else if (*e1s1 > 0 && *e2s2 < 0) {
+    // The range extends beyond the start and
+    // end of the current text block.
+    *aSelStatus = BlockSelectionStatus::eBlockInside;
+  } else if (*e1s1 <= 0 && *e2s2 >= 0) {
+    // The current text block contains the entire
+    // range.
+    *aSelStatus = BlockSelectionStatus::eBlockContains;
+  } else {
+    // The range partially intersects the block.
+    *aSelStatus = BlockSelectionStatus::eBlockPartial;
+  }
+
+  // Now create a range based on the intersection of the
+  // text block and range:
+
+  nsCOMPtr<nsINode> p1, p2;
+  uint32_t o1, o2;
+
+  // The start of the range will be the rightmost
+  // start node.
+
+  if (*e1s1 >= 0) {
+    p1 = eStart->mTextNode;
+    o1 = eStartOffset;
+  } else {
+    p1 = startContainer;
+    o1 = startOffset;
+  }
+
+  // The end of the range will be the leftmost
+  // end node.
+
+  if (*e2s2 <= 0) {
+    p2 = eEnd->mTextNode;
+    o2 = eEndOffset;
+  } else {
+    p2 = endContainer;
+    o2 = endOffset;
+  }
+
+  range = nsRange::Create(p1, o1, p2, o2, IgnoreErrors());
+  if (NS_WARN_IF(!range)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Now iterate over this range to figure out the selection's
+  // block offset and length.
+
+  RefPtr<FilteredContentIterator> filteredIter;
+  nsresult rv =
+      CreateFilteredContentIterator(range, getter_AddRefs(filteredIter));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Find the first text node in the range.
+  nsCOMPtr<nsIContent> content;
+  filteredIter->First();
+  if (!p1->IsText()) {
+    bool found = false;
+    for (; !filteredIter->IsDone(); filteredIter->Next()) {
+      nsINode* node = filteredIter->GetCurrentNode();
+      if (node->IsText()) {
+        p1 = node->AsText();
+        o1 = 0;
+        found = true;
+        break;
+      }
+    }
+    NS_ENSURE_TRUE(found, NS_ERROR_FAILURE);
+  }
+
+  // Find the last text node in the range.
+  filteredIter->Last();
+  if (!p2->IsText()) {
+    bool found = false;
+    for (; !filteredIter->IsDone(); filteredIter->Prev()) {
+      nsINode* node = filteredIter->GetCurrentNode();
+      if (node->IsText()) {
+        p2 = node->AsText();
+        o2 = p2->AsText()->Length();
+        found = true;
+
+        break;
+      }
+    }
+    NS_ENSURE_TRUE(found, NS_ERROR_FAILURE);
+  }
+
+  bool found = false;
+  *aSelLength = 0;
+
+  for (size_t i = 0; i < tableCount; i++) {
+    const UniquePtr<OffsetEntry>& entry = mOffsetTable[i];
+    LockOffsetEntryArrayLengthInDebugBuild(observer, mOffsetTable);
+    if (!found) {
+      if (entry->mTextNode == p1.get() &&
+          entry->OffsetInTextNodeIsInRangeOrEndOffset(o1)) {
+        *aSelOffset =
+            entry->mOffsetInTextInBlock + (o1 - entry->mOffsetInTextNode);
+        if (p1 == p2 && entry->OffsetInTextNodeIsInRangeOrEndOffset(o2)) {
+          // The start and end of the range are in the same offset
+          // entry. Calculate the length of the range then we're done.
+          *aSelLength = o2 - o1;
+          break;
+        }
+        // Add the length of the sub string in this offset entry
+        // that follows the start of the range.
+        *aSelLength = entry->EndOffsetInTextNode() - o1;
+        found = true;
+      }
+    } else {  // Found.
+      if (entry->mTextNode == p2.get() &&
+          entry->OffsetInTextNodeIsInRangeOrEndOffset(o2)) {
+        // We found the end of the range. Calculate the length of the
+        // sub string that is before the end of the range, then we're done.
+        *aSelLength += o2 - entry->mOffsetInTextNode;
+        break;
+      }
+      // The entire entry must be in the range.
+      *aSelLength += entry->mLength;
+    }
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult TextServicesDocument::GetRangeEndPoints(
+    const AbstractRange* aAbstractRange, nsINode** aStartContainer,
+    uint32_t* aStartOffset, nsINode** aEndContainer, uint32_t* aEndOffset) {
+  if (NS_WARN_IF(!aAbstractRange) || NS_WARN_IF(!aStartContainer) ||
+      NS_WARN_IF(!aEndContainer) || NS_WARN_IF(!aEndOffset)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsCOMPtr<nsINode> startContainer = aAbstractRange->GetStartContainer();
+  if (NS_WARN_IF(!startContainer)) {
+    return NS_ERROR_FAILURE;
+  }
+  nsCOMPtr<nsINode> endContainer = aAbstractRange->GetEndContainer();
+  if (NS_WARN_IF(!endContainer)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  startContainer.forget(aStartContainer);
+  endContainer.forget(aEndContainer);
+  *aStartOffset = aAbstractRange->StartOffset();
+  *aEndOffset = aAbstractRange->EndOffset();
+  return NS_OK;
+}
+
+// static
+nsresult TextServicesDocument::FirstTextNode(
+    FilteredContentIterator* aFilteredIter, IteratorStatus* aIteratorStatus) {
+  if (aIteratorStatus) {
+    *aIteratorStatus = IteratorStatus::eDone;
+  }
+
+  for (aFilteredIter->First(); !aFilteredIter->IsDone();
+       aFilteredIter->Next()) {
+    if (aFilteredIter->GetCurrentNode()->NodeType() == nsINode::TEXT_NODE) {
+      if (aIteratorStatus) {
+        *aIteratorStatus = IteratorStatus::eValid;
+      }
+      break;
+    }
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult TextServicesDocument::LastTextNode(
+    FilteredContentIterator* aFilteredIter, IteratorStatus* aIteratorStatus) {
+  if (aIteratorStatus) {
+    *aIteratorStatus = IteratorStatus::eDone;
+  }
+
+  for (aFilteredIter->Last(); !aFilteredIter->IsDone(); aFilteredIter->Prev()) {
+    if (aFilteredIter->GetCurrentNode()->NodeType() == nsINode::TEXT_NODE) {
+      if (aIteratorStatus) {
+        *aIteratorStatus = IteratorStatus::eValid;
+      }
+      break;
+    }
+  }
+
+  return NS_OK;
+}
+
+// static
+nsresult TextServicesDocument::FirstTextNodeInCurrentBlock(
+    FilteredContentIterator* aFilteredIter) {
+  NS_ENSURE_TRUE(aFilteredIter, NS_ERROR_NULL_POINTER);
+
+  ClearDidSkip(aFilteredIter);
+
+  // Walk backwards over adjacent text nodes until
+  // we hit a block boundary:
+  RefPtr<Text> lastTextNode;
+  while (!aFilteredIter->IsDone()) {
+    nsCOMPtr<nsIContent> content =
+        aFilteredIter->GetCurrentNode()->IsContent()
+            ? aFilteredIter->GetCurrentNode()->AsContent()
+            : nullptr;
+    // We don't observe layout updates, therefore, we should consider whether
+    // block or inline only with the default definition of the element.
+    if (lastTextNode && content &&
+        (HTMLEditUtils::IsBlockElement(*content,
+                                       BlockInlineCheck::UseHTMLDefaultStyle) ||
+         content->IsHTMLElement(nsGkAtoms::br))) {
+      break;
+    }
+    if (content && content->IsText()) {
+      if (lastTextNode && !TextServicesDocument::HasSameBlockNodeParent(
+                              *content->AsText(), *lastTextNode)) {
+        // We're done, the current text node is in a
+        // different block.
+        break;
+      }
+      lastTextNode = content->AsText();
+    }
+
+    aFilteredIter->Prev();
+
+    if (DidSkip(aFilteredIter)) {
+      break;
+    }
+  }
+
+  if (lastTextNode) {
+    aFilteredIter->PositionAt(lastTextNode);
+  }
+
+  // XXX: What should we return if last is null?
+
+  return NS_OK;
+}
+
+// static
+nsresult TextServicesDocument::FirstTextNodeInPrevBlock(
+    FilteredContentIterator* aFilteredIter) {
+  NS_ENSURE_TRUE(aFilteredIter, NS_ERROR_NULL_POINTER);
+
+  // XXX: What if mFilteredIter is not currently on a text node?
+
+  // Make sure mFilteredIter is pointing to the first text node in the
+  // current block:
+
+  nsresult rv = FirstTextNodeInCurrentBlock(aFilteredIter);
+
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
+
+  // Point mFilteredIter to the first node before the first text node:
+
+  aFilteredIter->Prev();
+
+  if (aFilteredIter->IsDone()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Now find the first text node of the next block:
+
+  return FirstTextNodeInCurrentBlock(aFilteredIter);
+}
+
+// static
+nsresult TextServicesDocument::FirstTextNodeInNextBlock(
+    FilteredContentIterator* aFilteredIter) {
+  bool crossedBlockBoundary = false;
+
+  NS_ENSURE_TRUE(aFilteredIter, NS_ERROR_NULL_POINTER);
+
+  ClearDidSkip(aFilteredIter);
+
+  RefPtr<Text> previousTextNode;
+  while (!aFilteredIter->IsDone()) {
+    if (nsCOMPtr<nsIContent> content =
+            aFilteredIter->GetCurrentNode()->IsContent()
+                ? aFilteredIter->GetCurrentNode()->AsContent()
+                : nullptr) {
+      if (content->IsText()) {
+        if (crossedBlockBoundary ||
+            (previousTextNode && !TextServicesDocument::HasSameBlockNodeParent(
+                                     *previousTextNode, *content->AsText()))) {
+          break;
+        }
+        previousTextNode = content->AsText();
+      }
+      // We don't observe layout updates, therefore, we should consider whether
+      // block or inline only with the default definition of the element.
+      else if (!crossedBlockBoundary &&
+               (HTMLEditUtils::IsBlockElement(
+                    *content, BlockInlineCheck::UseHTMLDefaultStyle) ||
+                content->IsHTMLElement(nsGkAtoms::br))) {
+        crossedBlockBoundary = true;
+      }
+    }
+
+    aFilteredIter->Next();
+
+    if (!crossedBlockBoundary && DidSkip(aFilteredIter)) {
+      crossedBlockBoundary = true;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult TextServicesDocument::GetFirstTextNodeInPrevBlock(
+    nsIContent** aContent) {
+  NS_ENSURE_TRUE(aContent, NS_ERROR_NULL_POINTER);
+
+  *aContent = 0;
+
+  // Save the iterator's current content node so we can restore
+  // it when we are done:
+
+  nsINode* node = mFilteredIter->GetCurrentNode();
+
+  nsresult rv = FirstTextNodeInPrevBlock(mFilteredIter);
+
+  if (NS_FAILED(rv)) {
+    // Try to restore the iterator before returning.
+    mFilteredIter->PositionAt(node);
+    return rv;
+  }
+
+  if (!mFilteredIter->IsDone()) {
+    nsCOMPtr<nsIContent> current =
+        mFilteredIter->GetCurrentNode()->IsContent()
+            ? mFilteredIter->GetCurrentNode()->AsContent()
+            : nullptr;
+    current.forget(aContent);
+  }
+
+  // Restore the iterator:
+
+  return mFilteredIter->PositionAt(node);
+}
+
+nsresult TextServicesDocument::GetFirstTextNodeInNextBlock(
+    nsIContent** aContent) {
+  NS_ENSURE_TRUE(aContent, NS_ERROR_NULL_POINTER);
+
+  *aContent = 0;
+
+  // Save the iterator's current content node so we can restore
+  // it when we are done:
+
+  nsINode* node = mFilteredIter->GetCurrentNode();
+
+  nsresult rv = FirstTextNodeInNextBlock(mFilteredIter);
+
+  if (NS_FAILED(rv)) {
+    // Try to restore the iterator before returning.
+    mFilteredIter->PositionAt(node);
+    return rv;
+  }
+
+  if (!mFilteredIter->IsDone()) {
+    nsCOMPtr<nsIContent> current =
+        mFilteredIter->GetCurrentNode()->IsContent()
+            ? mFilteredIter->GetCurrentNode()->AsContent()
+            : nullptr;
+    current.forget(aContent);
+  }
+
+  // Restore the iterator:
+  return mFilteredIter->PositionAt(node);
+}
+
+Result<TextServicesDocument::IteratorStatus, nsresult>
+TextServicesDocument::OffsetEntryArray::Init(
+    FilteredContentIterator& aFilteredIter, IteratorStatus aIteratorStatus,
+    nsRange* aIterRange, nsAString* aAllTextInBlock /* = nullptr */) {
+  Clear();
+
+  if (aAllTextInBlock) {
+    aAllTextInBlock->Truncate();
+  }
+
+  if (aIteratorStatus == IteratorStatus::eDone) {
+    return IteratorStatus::eDone;
+  }
+
+  // If we have an aIterRange, retrieve the endpoints so
+  // they can be used in the while loop below to trim entries
+  // for text nodes that are partially selected by aIterRange.
+
+  nsCOMPtr<nsINode> rngStartNode, rngEndNode;
+  uint32_t rngStartOffset = 0, rngEndOffset = 0;
+  if (aIterRange) {
+    nsresult rv = TextServicesDocument::GetRangeEndPoints(
+        aIterRange, getter_AddRefs(rngStartNode), &rngStartOffset,
+        getter_AddRefs(rngEndNode), &rngEndOffset);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("TextServicesDocument::GetRangeEndPoints() failed");
+      return Err(rv);
+    }
+  }
+
+  // The text service could have added text nodes to the beginning
+  // of the current block and called this method again. Make sure
+  // we really are at the beginning of the current block:
+
+  nsresult rv =
+      TextServicesDocument::FirstTextNodeInCurrentBlock(&aFilteredIter);
+  if (NS_FAILED(rv)) {
+    NS_WARNING("TextServicesDocument::FirstTextNodeInCurrentBlock() failed");
+    return Err(rv);
+  }
+
+  TextServicesDocument::ClearDidSkip(&aFilteredIter);
+
+  uint32_t offset = 0;
+  RefPtr<Text> firstTextNode, previousTextNode;
+  while (!aFilteredIter.IsDone()) {
+    if (nsCOMPtr<nsIContent> content =
+            aFilteredIter.GetCurrentNode()->IsContent()
+                ? aFilteredIter.GetCurrentNode()->AsContent()
+                : nullptr) {
+      // We don't observe layout updates, therefore, we should consider whether
+      // block or inline only with the default definition of the element.
+      if (HTMLEditUtils::IsBlockElement(
+              *content, BlockInlineCheck::UseHTMLDefaultStyle) ||
+          content->IsHTMLElement(nsGkAtoms::br)) {
+        break;
+      }
+      if (content->IsText()) {
+        if (previousTextNode && !TextServicesDocument::HasSameBlockNodeParent(
+                                    *previousTextNode, *content->AsText())) {
+          break;
+        }
+
+        nsString str;
+        content->AsText()->GetNodeValue(str);
+
+        // Add an entry for this text node into the offset table:
+
+        UniquePtr<OffsetEntry>& entry = *AppendElement(
+            MakeUnique<OffsetEntry>(*content->AsText(), offset, str.Length()));
+        LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+
+        // If one or both of the endpoints of the iteration range
+        // are in the text node for this entry, make sure the entry
+        // only accounts for the portion of the text node that is
+        // in the range.
+
+        uint32_t startOffset = 0;
+        uint32_t endOffset = str.Length();
+        bool adjustStr = false;
+
+        if (entry->mTextNode == rngStartNode) {
+          entry->mOffsetInTextNode = startOffset = rngStartOffset;
+          adjustStr = true;
+        }
+
+        if (entry->mTextNode == rngEndNode) {
+          endOffset = rngEndOffset;
+          adjustStr = true;
+        }
+
+        if (adjustStr) {
+          entry->mLength = endOffset - startOffset;
+          str = Substring(str, startOffset, entry->mLength);
+        }
+
+        offset += str.Length();
+
+        if (aAllTextInBlock) {
+          // Append the text node's string to the output string:
+          if (!firstTextNode) {
+            *aAllTextInBlock = str;
+          } else {
+            *aAllTextInBlock += str;
+          }
+        }
+
+        previousTextNode = content->AsText();
+
+        if (!firstTextNode) {
+          firstTextNode = content->AsText();
+        }
+      }
+    }
+
+    aFilteredIter.Next();
+
+    if (TextServicesDocument::DidSkip(&aFilteredIter)) {
+      break;
+    }
+  }
+
+  if (firstTextNode) {
+    // Always leave the iterator pointing at the first
+    // text node of the current block!
+    aFilteredIter.PositionAt(firstTextNode);
+    return aIteratorStatus;
+  }
+
+  // If we never ran across a text node, the iterator
+  // might have been pointing to something invalid to
+  // begin with.
+  return IteratorStatus::eDone;
+}
+
+void TextServicesDocument::OffsetEntryArray::RemoveInvalidElements() {
+  for (size_t i = 0; i < Length();) {
+    if (ElementAt(i)->mIsValid) {
+      i++;
+      continue;
+    }
+
+    RemoveElementAt(i);
+    if (!mSelection.IsSet()) {
+      continue;
+    }
+    if (mSelection.StartIndex() == i) {
+      NS_ASSERTION(false, "What should we do in this case?");
+      mSelection.Reset();
+    } else if (mSelection.StartIndex() > i) {
+      MOZ_DIAGNOSTIC_ASSERT(mSelection.StartIndex() - 1 < Length());
+      MOZ_DIAGNOSTIC_ASSERT(mSelection.EndIndex() - 1 < Length());
+      mSelection.SetIndexes(mSelection.StartIndex() - 1,
+                            mSelection.EndIndex() - 1);
+    } else if (mSelection.EndIndex() >= i) {
+      MOZ_DIAGNOSTIC_ASSERT(mSelection.EndIndex() - 1 < Length());
+      mSelection.SetIndexes(mSelection.StartIndex(), mSelection.EndIndex() - 1);
+    }
+  }
+}
+
+nsresult TextServicesDocument::OffsetEntryArray::SplitElementAt(
+    size_t aIndex, uint32_t aOffsetInTextNode) {
+  OffsetEntry* leftEntry = ElementAt(aIndex).get();
+  MOZ_ASSERT(leftEntry);
+  NS_ASSERTION((aOffsetInTextNode > 0), "aOffsetInTextNode == 0");
+  NS_ASSERTION((aOffsetInTextNode < leftEntry->mLength),
+               "aOffsetInTextNode >= mLength");
+
+  if (aOffsetInTextNode < 1 || aOffsetInTextNode >= leftEntry->mLength) {
+    return NS_ERROR_FAILURE;
+  }
+
+  const uint32_t oldLength = leftEntry->mLength - aOffsetInTextNode;
+
+  // XXX(Bug 1631371) Check if this should use a fallible operation as it
+  // pretended earlier.
+  UniquePtr<OffsetEntry>& rightEntry = *InsertElementAt(
+      aIndex + 1,
+      MakeUnique<OffsetEntry>(leftEntry->mTextNode,
+                              leftEntry->mOffsetInTextInBlock + oldLength,
+                              aOffsetInTextNode));
+  LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+  leftEntry->mLength = oldLength;
+  rightEntry->mOffsetInTextNode = leftEntry->mOffsetInTextNode + oldLength;
+
+  return NS_OK;
+}
+
+Maybe<size_t> TextServicesDocument::OffsetEntryArray::FirstIndexOf(
+    const Text& aTextNode) const {
+  for (size_t i = 0; i < Length(); i++) {
+    if (ElementAt(i)->mTextNode == &aTextNode) {
+      return Some(i);
+    }
+  }
+  return Nothing();
+}
+
+// Spellchecker code has this. See bug 211343
+#define IS_NBSP_CHAR(c) (((unsigned char)0xa0) == (c))
+
+Result<EditorDOMRangeInTexts, nsresult>
+TextServicesDocument::OffsetEntryArray::FindWordRange(
+    nsAString& aAllTextInBlock, const EditorRawDOMPoint& aStartPointToScan) {
+  MOZ_ASSERT(aStartPointToScan.IsInTextNode());
+  // It's assumed that aNode is a text node. The first thing
+  // we do is get its index in the offset table so we can
+  // calculate the dom point's string offset.
+  Maybe<size_t> maybeEntryIndex =
+      FirstIndexOf(*aStartPointToScan.ContainerAs<Text>());
+  if (NS_WARN_IF(maybeEntryIndex.isNothing())) {
+    NS_WARNING(
+        "TextServicesDocument::OffsetEntryArray::FirstIndexOf() didn't find "
+        "entries");
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  // Next we map offset into a string offset.
+
+  const UniquePtr<OffsetEntry>& entry = ElementAt(*maybeEntryIndex);
+  LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+  uint32_t strOffset = entry->mOffsetInTextInBlock +
+                       aStartPointToScan.Offset() - entry->mOffsetInTextNode;
+
+  // Now we use the word breaker to find the beginning and end
+  // of the word from our calculated string offset.
+
+  const char16_t* str = aAllTextInBlock.BeginReading();
+  MOZ_ASSERT(strOffset <= aAllTextInBlock.Length(),
+             "The string offset shouldn't be greater than the string length!");
+
+  intl::WordRange res = intl::WordBreaker::FindWord(aAllTextInBlock, strOffset);
+
+  // Strip out the NBSPs at the ends
+  while (res.mBegin <= res.mEnd && IS_NBSP_CHAR(str[res.mBegin])) {
+    res.mBegin++;
+  }
+  if (str[res.mEnd] == static_cast<char16_t>(0x20)) {
+    uint32_t realEndWord = res.mEnd - 1;
+    while (realEndWord > res.mBegin && IS_NBSP_CHAR(str[realEndWord])) {
+      realEndWord--;
+    }
+    if (realEndWord < res.mEnd - 1) {
+      res.mEnd = realEndWord + 1;
+    }
+  }
+
+  // Now that we have the string offsets for the beginning
+  // and end of the word, run through the offset table and
+  // convert them back into dom points.
+
+  EditorDOMPointInText wordStart, wordEnd;
+  size_t lastIndex = Length() - 1;
+  for (size_t i = 0; i <= lastIndex; i++) {
+    // Check to see if res.mBegin is within the range covered
+    // by this entry. Note that if res.mBegin is after the last
+    // character covered by this entry, we will use the next
+    // entry if there is one.
+    const UniquePtr<OffsetEntry>& entry = ElementAt(i);
+    LockOffsetEntryArrayLengthInDebugBuild(observer, *this);
+    if (entry->mOffsetInTextInBlock <= res.mBegin &&
+        (res.mBegin < entry->EndOffsetInTextInBlock() ||
+         (res.mBegin == entry->EndOffsetInTextInBlock() && i == lastIndex))) {
+      wordStart.Set(entry->mTextNode, entry->mOffsetInTextNode + res.mBegin -
+                                          entry->mOffsetInTextInBlock);
+    }
+
+    // Check to see if res.mEnd is within the range covered
+    // by this entry.
+    if (entry->mOffsetInTextInBlock <= res.mEnd &&
+        res.mEnd <= entry->EndOffsetInTextInBlock()) {
+      if (res.mBegin == res.mEnd &&
+          res.mEnd == entry->EndOffsetInTextInBlock() && i != lastIndex) {
+        // Wait for the next round so that we use the same entry
+        // we did for aWordStartNode.
+        continue;
+      }
+
+      wordEnd.Set(entry->mTextNode, entry->mOffsetInTextNode + res.mEnd -
+                                        entry->mOffsetInTextInBlock);
+      break;
+    }
+  }
+
+  return EditorDOMRangeInTexts(wordStart, wordEnd);
+}
+
+/**
+ * nsIEditActionListener implementation:
+ *   Don't implement the behavior directly here.  The methods won't be called
+ *   if the instance is created for inline spell checker created for editor.
+ *   If you need to listen a new edit action, you need to add similar
+ *   non-virtual method and you need to call it from EditorBase directly.
+ */
+
+NS_IMETHODIMP
+TextServicesDocument::DidDeleteNode(nsINode* aChild, nsresult aResult) {
+  if (NS_WARN_IF(NS_FAILED(aResult)) || NS_WARN_IF(!aChild) ||
+      !aChild->IsContent()) {
+    return NS_OK;
+  }
+  DidDeleteContent(*aChild->AsContent());
+  return NS_OK;
+}
+
+NS_IMETHODIMP TextServicesDocument::DidJoinContents(
+    const EditorRawDOMPoint& aJoinedPoint, const nsINode* aRemovedNode) {
+  if (MOZ_UNLIKELY(NS_WARN_IF(!aJoinedPoint.IsSetAndValid()) ||
+                   NS_WARN_IF(!aRemovedNode->IsContent()))) {
+    return NS_OK;
+  }
+  DidJoinContents(aJoinedPoint, *aRemovedNode->AsContent());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TextServicesDocument::DidInsertText(CharacterData* aTextNode, int32_t aOffset,
+                                    const nsAString& aString,
+                                    nsresult aResult) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TextServicesDocument::WillDeleteText(CharacterData* aTextNode, int32_t aOffset,
+                                     int32_t aLength) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TextServicesDocument::WillDeleteRanges(
+    const nsTArray<RefPtr<nsRange>>& aRangesToDelete) {
+  return NS_OK;
+}
+
+#undef LockOffsetEntryArrayLengthInDebugBuild
+
+}  // namespace mozilla