Add m-esr52 at 52.6.0

1 files changed, 2043 insertions, 0 deletions

diff --git a/extensions/spellcheck/src/mozInlineSpellChecker.cpp b/extensions/spellcheck/src/mozInlineSpellChecker.cpp
new file mode 100644
index 000000000..96011a37e
--- /dev/null
+++ b/extensions/spellcheck/src/mozInlineSpellChecker.cpp
@@ -0,0 +1,2043 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=2 sts=2 tw=80: */
+/* 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/. */
+
+/**
+ * This class is called by the editor to handle spellchecking after various
+ * events. The main entrypoint is SpellCheckAfterEditorChange, which is called
+ * when the text is changed.
+ *
+ * It is VERY IMPORTANT that we do NOT do any operations that might cause DOM
+ * notifications to be flushed when we are called from the editor. This is
+ * because the call might originate from a frame, and flushing the
+ * notifications might cause that frame to be deleted.
+ *
+ * Using the WordUtil class to find words causes DOM notifications to be
+ * flushed because it asks for style information. As a result, we post an event
+ * and do all of the spellchecking in that event handler, which occurs later.
+ * We store all DOM pointers in ranges because they are kept up-to-date with
+ * DOM changes that may have happened while the event was on the queue.
+ *
+ * We also allow the spellcheck to be suspended and resumed later. This makes
+ * large pastes or initializations with a lot of text not hang the browser UI.
+ *
+ * An optimization is the mNeedsCheckAfterNavigation flag. This is set to
+ * true when we get any change, and false once there is no possibility
+ * something changed that we need to check on navigation. Navigation events
+ * tend to be a little tricky because we want to check the current word on
+ * exit if something has changed. If we navigate inside the word, we don't want
+ * to do anything. As a result, this flag is cleared in FinishNavigationEvent
+ * when we know that we are checking as a result of navigation.
+ */
+
+#include "mozilla/EditorBase.h"
+#include "mozilla/EditorUtils.h"
+#include "mozilla/Services.h"
+#include "mozilla/dom/Selection.h"
+#include "mozInlineSpellChecker.h"
+#include "mozInlineSpellWordUtil.h"
+#include "mozISpellI18NManager.h"
+#include "nsCOMPtr.h"
+#include "nsCRT.h"
+#include "nsIDOMNode.h"
+#include "nsIDOMDocument.h"
+#include "nsIDOMElement.h"
+#include "nsIDOMHTMLElement.h"
+#include "nsIDOMMouseEvent.h"
+#include "nsIDOMKeyEvent.h"
+#include "nsIDOMNode.h"
+#include "nsIDOMNodeList.h"
+#include "nsIDOMEvent.h"
+#include "nsGenericHTMLElement.h"
+#include "nsRange.h"
+#include "nsIPlaintextEditor.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefService.h"
+#include "nsIRunnable.h"
+#include "nsISelection.h"
+#include "nsISelectionPrivate.h"
+#include "nsISelectionController.h"
+#include "nsIServiceManager.h"
+#include "nsITextServicesFilter.h"
+#include "nsString.h"
+#include "nsThreadUtils.h"
+#include "nsUnicharUtils.h"
+#include "nsIContent.h"
+#include "nsRange.h"
+#include "nsContentUtils.h"
+#include "nsIObserverService.h"
+#include "nsITextControlElement.h"
+#include "prtime.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+// Set to spew messages to the console about what is happening.
+//#define DEBUG_INLINESPELL
+
+// the number of milliseconds that we will take at once to do spellchecking
+#define INLINESPELL_CHECK_TIMEOUT 50
+
+// The number of words to check before we look at the time to see if
+// INLINESPELL_CHECK_TIMEOUT ms have elapsed. This prevents us from spending
+// too much time checking the clock. Note that misspelled words count for
+// more than one word in this calculation.
+#define INLINESPELL_TIMEOUT_CHECK_FREQUENCY 50
+
+// This number is the number of checked words a misspelled word counts for
+// when we're checking the time to see if the alloted time is up for
+// spellchecking. Misspelled words take longer to process since we have to
+// create a range, so they count more. The exact number isn't very important
+// since this just controls how often we check the current time.
+#define MISSPELLED_WORD_COUNT_PENALTY 4
+
+// These notifications are broadcast when spell check starts and ends.  STARTED
+// must always be followed by ENDED.
+#define INLINESPELL_STARTED_TOPIC "inlineSpellChecker-spellCheck-started"
+#define INLINESPELL_ENDED_TOPIC "inlineSpellChecker-spellCheck-ended"
+
+static bool ContentIsDescendantOf(nsINode* aPossibleDescendant,
+                                    nsINode* aPossibleAncestor);
+
+static const char kMaxSpellCheckSelectionSize[] = "extensions.spellcheck.inline.max-misspellings";
+
+mozInlineSpellStatus::mozInlineSpellStatus(mozInlineSpellChecker* aSpellChecker)
+    : mSpellChecker(aSpellChecker), mWordCount(0)
+{
+}
+
+// mozInlineSpellStatus::InitForEditorChange
+//
+//    This is the most complicated case. For changes, we need to compute the
+//    range of stuff that changed based on the old and new caret positions,
+//    as well as use a range possibly provided by the editor (start and end,
+//    which are usually nullptr) to get a range with the union of these.
+
+nsresult
+mozInlineSpellStatus::InitForEditorChange(
+    EditAction aAction,
+    nsIDOMNode* aAnchorNode, int32_t aAnchorOffset,
+    nsIDOMNode* aPreviousNode, int32_t aPreviousOffset,
+    nsIDOMNode* aStartNode, int32_t aStartOffset,
+    nsIDOMNode* aEndNode, int32_t aEndOffset)
+{
+  nsresult rv;
+
+  nsCOMPtr<nsIDOMDocument> doc;
+  rv = GetDocument(getter_AddRefs(doc));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // save the anchor point as a range so we can find the current word later
+  rv = PositionToCollapsedRange(doc, aAnchorNode, aAnchorOffset,
+                                getter_AddRefs(mAnchorRange));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsINode> prevNode = do_QueryInterface(aPreviousNode);
+  NS_ENSURE_STATE(prevNode);
+
+  bool deleted = aAction == EditAction::deleteSelection;
+  if (aAction == EditAction::insertIMEText) {
+    // IME may remove the previous node if it cancels composition when
+    // there is no text around the composition.
+    deleted = !prevNode->IsInComposedDoc();
+  }
+
+  if (deleted) {
+    // Deletes are easy, the range is just the current anchor. We set the range
+    // to check to be empty, FinishInitOnEvent will fill in the range to be
+    // the current word.
+    mOp = eOpChangeDelete;
+    mRange = nullptr;
+    return NS_OK;
+  }
+
+  mOp = eOpChange;
+
+  // range to check
+  mRange = new nsRange(prevNode);
+
+  // ...we need to put the start and end in the correct order
+  int16_t cmpResult;
+  rv = mAnchorRange->ComparePoint(aPreviousNode, aPreviousOffset, &cmpResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (cmpResult < 0) {
+    // previous anchor node is before the current anchor
+    rv = mRange->SetStart(aPreviousNode, aPreviousOffset);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mRange->SetEnd(aAnchorNode, aAnchorOffset);
+  } else {
+    // previous anchor node is after (or the same as) the current anchor
+    rv = mRange->SetStart(aAnchorNode, aAnchorOffset);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mRange->SetEnd(aPreviousNode, aPreviousOffset);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // On insert save this range: DoSpellCheck optimizes things in this range.
+  // Otherwise, just leave this nullptr.
+  if (aAction == EditAction::insertText)
+    mCreatedRange = mRange;
+
+  // if we were given a range, we need to expand our range to encompass it
+  if (aStartNode && aEndNode) {
+    rv = mRange->ComparePoint(aStartNode, aStartOffset, &cmpResult);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (cmpResult < 0) { // given range starts before
+      rv = mRange->SetStart(aStartNode, aStartOffset);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    rv = mRange->ComparePoint(aEndNode, aEndOffset, &cmpResult);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (cmpResult > 0) { // given range ends after
+      rv = mRange->SetEnd(aEndNode, aEndOffset);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  return NS_OK;
+}
+
+// mozInlineSpellStatis::InitForNavigation
+//
+//    For navigation events, we just need to store the new and old positions.
+//
+//    In some cases, we detect that we shouldn't check. If this event should
+//    not be processed, *aContinue will be false.
+
+nsresult
+mozInlineSpellStatus::InitForNavigation(
+    bool aForceCheck, int32_t aNewPositionOffset,
+    nsIDOMNode* aOldAnchorNode, int32_t aOldAnchorOffset,
+    nsIDOMNode* aNewAnchorNode, int32_t aNewAnchorOffset,
+    bool* aContinue)
+{
+  nsresult rv;
+  mOp = eOpNavigation;
+
+  mForceNavigationWordCheck = aForceCheck;
+  mNewNavigationPositionOffset = aNewPositionOffset;
+
+  // get the root node for checking
+  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mSpellChecker->mEditor, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIDOMElement> rootElt;
+  rv = editor->GetRootElement(getter_AddRefs(rootElt));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // the anchor node might not be in the DOM anymore, check
+  nsCOMPtr<nsINode> root = do_QueryInterface(rootElt, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsINode> currentAnchor = do_QueryInterface(aOldAnchorNode, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (root && currentAnchor && ! ContentIsDescendantOf(currentAnchor, root)) {
+    *aContinue = false;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIDOMDocument> doc;
+  rv = GetDocument(getter_AddRefs(doc));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = PositionToCollapsedRange(doc, aOldAnchorNode, aOldAnchorOffset,
+                                getter_AddRefs(mOldNavigationAnchorRange));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = PositionToCollapsedRange(doc, aNewAnchorNode, aNewAnchorOffset,
+                                getter_AddRefs(mAnchorRange));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aContinue = true;
+  return NS_OK;
+}
+
+// mozInlineSpellStatus::InitForSelection
+//
+//    It is easy for selections since we always re-check the spellcheck
+//    selection.
+
+nsresult
+mozInlineSpellStatus::InitForSelection()
+{
+  mOp = eOpSelection;
+  return NS_OK;
+}
+
+// mozInlineSpellStatus::InitForRange
+//
+//    Called to cause the spellcheck of the given range. This will look like
+//    a change operation over the given range.
+
+nsresult
+mozInlineSpellStatus::InitForRange(nsRange* aRange)
+{
+  mOp = eOpChange;
+  mRange = aRange;
+  return NS_OK;
+}
+
+// mozInlineSpellStatus::FinishInitOnEvent
+//
+//    Called when the event is triggered to complete initialization that
+//    might require the WordUtil. This calls to the operation-specific
+//    initializer, and also sets the range to be the entire element if it
+//    is nullptr.
+//
+//    Watch out: the range might still be nullptr if there is nothing to do,
+//    the caller will have to check for this.
+
+nsresult
+mozInlineSpellStatus::FinishInitOnEvent(mozInlineSpellWordUtil& aWordUtil)
+{
+  nsresult rv;
+  if (! mRange) {
+    rv = mSpellChecker->MakeSpellCheckRange(nullptr, 0, nullptr, 0,
+                                            getter_AddRefs(mRange));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  switch (mOp) {
+    case eOpChange:
+      if (mAnchorRange)
+        return FillNoCheckRangeFromAnchor(aWordUtil);
+      break;
+    case eOpChangeDelete:
+      if (mAnchorRange) {
+        rv = FillNoCheckRangeFromAnchor(aWordUtil);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+      // Delete events will have no range for the changed text (because it was
+      // deleted), and InitForEditorChange will set it to nullptr. Here, we select
+      // the entire word to cause any underlining to be removed.
+      mRange = mNoCheckRange;
+      break;
+    case eOpNavigation:
+      return FinishNavigationEvent(aWordUtil);
+    case eOpSelection:
+      // this gets special handling in ResumeCheck
+      break;
+    case eOpResume:
+      // everything should be initialized already in this case
+      break;
+    default:
+      NS_NOTREACHED("Bad operation");
+      return NS_ERROR_NOT_INITIALIZED;
+  }
+  return NS_OK;
+}
+
+// mozInlineSpellStatus::FinishNavigationEvent
+//
+//    This verifies that we need to check the word at the previous caret
+//    position. Now that we have the word util, we can find the word belonging
+//    to the previous caret position. If the new position is inside that word,
+//    we don't want to do anything. In this case, we'll nullptr out mRange so
+//    that the caller will know not to continue.
+//
+//    Notice that we don't set mNoCheckRange. We check here whether the cursor
+//    is in the word that needs checking, so it isn't necessary. Plus, the
+//    spellchecker isn't guaranteed to only check the given word, and it could
+//    remove the underline from the new word under the cursor.
+
+nsresult
+mozInlineSpellStatus::FinishNavigationEvent(mozInlineSpellWordUtil& aWordUtil)
+{
+  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mSpellChecker->mEditor);
+  if (! editor)
+    return NS_ERROR_FAILURE; // editor is gone
+
+  NS_ASSERTION(mAnchorRange, "No anchor for navigation!");
+  nsCOMPtr<nsIDOMNode> newAnchorNode, oldAnchorNode;
+  int32_t newAnchorOffset, oldAnchorOffset;
+
+  // get the DOM position of the old caret, the range should be collapsed
+  nsresult rv = mOldNavigationAnchorRange->GetStartContainer(
+      getter_AddRefs(oldAnchorNode));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mOldNavigationAnchorRange->GetStartOffset(&oldAnchorOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // find the word on the old caret position, this is the one that we MAY need
+  // to check
+  RefPtr<nsRange> oldWord;
+  rv = aWordUtil.GetRangeForWord(oldAnchorNode, oldAnchorOffset,
+                                 getter_AddRefs(oldWord));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // aWordUtil.GetRangeForWord flushes pending notifications, check editor again.
+  editor = do_QueryReferent(mSpellChecker->mEditor);
+  if (! editor)
+    return NS_ERROR_FAILURE; // editor is gone
+
+  // get the DOM position of the new caret, the range should be collapsed
+  rv = mAnchorRange->GetStartContainer(getter_AddRefs(newAnchorNode));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mAnchorRange->GetStartOffset(&newAnchorOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // see if the new cursor position is in the word of the old cursor position
+  bool isInRange = false;
+  if (! mForceNavigationWordCheck) {
+    rv = oldWord->IsPointInRange(newAnchorNode,
+                                 newAnchorOffset + mNewNavigationPositionOffset,
+                                 &isInRange);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (isInRange) {
+    // caller should give up
+    mRange = nullptr;
+  } else {
+    // check the old word
+    mRange = oldWord;
+
+    // Once we've spellchecked the current word, we don't need to spellcheck
+    // for any more navigation events.
+    mSpellChecker->mNeedsCheckAfterNavigation = false;
+  }
+  return NS_OK;
+}
+
+// mozInlineSpellStatus::FillNoCheckRangeFromAnchor
+//
+//    Given the mAnchorRange object, computes the range of the word it is on
+//    (if any) and fills that range into mNoCheckRange. This is used for
+//    change and navigation events to know which word we should skip spell
+//    checking on
+
+nsresult
+mozInlineSpellStatus::FillNoCheckRangeFromAnchor(
+    mozInlineSpellWordUtil& aWordUtil)
+{
+  nsCOMPtr<nsIDOMNode> anchorNode;
+  nsresult rv = mAnchorRange->GetStartContainer(getter_AddRefs(anchorNode));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int32_t anchorOffset;
+  rv = mAnchorRange->GetStartOffset(&anchorOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return aWordUtil.GetRangeForWord(anchorNode, anchorOffset,
+                                   getter_AddRefs(mNoCheckRange));
+}
+
+// mozInlineSpellStatus::GetDocument
+//
+//    Returns the nsIDOMDocument object for the document for the
+//    current spellchecker.
+
+nsresult
+mozInlineSpellStatus::GetDocument(nsIDOMDocument** aDocument)
+{
+  nsresult rv;
+  *aDocument = nullptr;
+  if (! mSpellChecker->mEditor)
+    return NS_ERROR_UNEXPECTED;
+
+  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mSpellChecker->mEditor, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIDOMDocument> domDoc;
+  rv = editor->GetDocument(getter_AddRefs(domDoc));
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(domDoc, NS_ERROR_NULL_POINTER);
+  domDoc.forget(aDocument);
+  return NS_OK;
+}
+
+// mozInlineSpellStatus::PositionToCollapsedRange
+//
+//    Converts a given DOM position to a collapsed range covering that
+//    position. We use ranges to store DOM positions becuase they stay
+//    updated as the DOM is changed.
+
+nsresult
+mozInlineSpellStatus::PositionToCollapsedRange(nsIDOMDocument* aDocument,
+    nsIDOMNode* aNode, int32_t aOffset, nsIDOMRange** aRange)
+{
+  *aRange = nullptr;
+  nsCOMPtr<nsIDOMRange> range;
+  nsresult rv = aDocument->CreateRange(getter_AddRefs(range));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = range->SetStart(aNode, aOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = range->SetEnd(aNode, aOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  range.swap(*aRange);
+  return NS_OK;
+}
+
+// mozInlineSpellResume
+
+class mozInlineSpellResume : public Runnable
+{
+public:
+  mozInlineSpellResume(const mozInlineSpellStatus& aStatus,
+                       uint32_t aDisabledAsyncToken)
+    : mDisabledAsyncToken(aDisabledAsyncToken), mStatus(aStatus) {}
+
+  nsresult Post()
+  {
+    return NS_DispatchToMainThread(this);
+  }
+
+  NS_IMETHOD Run() override
+  {
+    // Discard the resumption if the spell checker was disabled after the
+    // resumption was scheduled.
+    if (mDisabledAsyncToken == mStatus.mSpellChecker->mDisabledAsyncToken) {
+      mStatus.mSpellChecker->ResumeCheck(&mStatus);
+    }
+    return NS_OK;
+  }
+
+private:
+  uint32_t mDisabledAsyncToken;
+  mozInlineSpellStatus mStatus;
+};
+
+// Used as the nsIEditorSpellCheck::InitSpellChecker callback.
+class InitEditorSpellCheckCallback final : public nsIEditorSpellCheckCallback
+{
+  ~InitEditorSpellCheckCallback() {}
+public:
+  NS_DECL_ISUPPORTS
+
+  explicit InitEditorSpellCheckCallback(mozInlineSpellChecker* aSpellChecker)
+    : mSpellChecker(aSpellChecker) {}
+
+  NS_IMETHOD EditorSpellCheckDone() override
+  {
+    return mSpellChecker ? mSpellChecker->EditorSpellCheckInited() : NS_OK;
+  }
+
+  void Cancel()
+  {
+    mSpellChecker = nullptr;
+  }
+
+private:
+  RefPtr<mozInlineSpellChecker> mSpellChecker;
+};
+NS_IMPL_ISUPPORTS(InitEditorSpellCheckCallback, nsIEditorSpellCheckCallback)
+
+
+NS_INTERFACE_MAP_BEGIN(mozInlineSpellChecker)
+  NS_INTERFACE_MAP_ENTRY(nsIInlineSpellChecker)
+  NS_INTERFACE_MAP_ENTRY(nsIEditActionListener)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMEventListener)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMEventListener)
+  NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(mozInlineSpellChecker)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(mozInlineSpellChecker)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(mozInlineSpellChecker)
+
+NS_IMPL_CYCLE_COLLECTION(mozInlineSpellChecker,
+                         mSpellCheck,
+                         mTreeWalker,
+                         mCurrentSelectionAnchorNode)
+
+mozInlineSpellChecker::SpellCheckingState
+  mozInlineSpellChecker::gCanEnableSpellChecking =
+  mozInlineSpellChecker::SpellCheck_Uninitialized;
+
+mozInlineSpellChecker::mozInlineSpellChecker() :
+    mNumWordsInSpellSelection(0),
+    mMaxNumWordsInSpellSelection(250),
+    mNumPendingSpellChecks(0),
+    mNumPendingUpdateCurrentDictionary(0),
+    mDisabledAsyncToken(0),
+    mNeedsCheckAfterNavigation(false),
+    mFullSpellCheckScheduled(false)
+{
+  nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
+  if (prefs)
+    prefs->GetIntPref(kMaxSpellCheckSelectionSize, &mMaxNumWordsInSpellSelection); 
+  mMaxMisspellingsPerCheck = mMaxNumWordsInSpellSelection * 3 / 4;
+}
+
+mozInlineSpellChecker::~mozInlineSpellChecker()
+{
+}
+
+NS_IMETHODIMP
+mozInlineSpellChecker::GetSpellChecker(nsIEditorSpellCheck **aSpellCheck)
+{
+  *aSpellCheck = mSpellCheck;
+  NS_IF_ADDREF(*aSpellCheck);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+mozInlineSpellChecker::Init(nsIEditor *aEditor)
+{
+  mEditor = do_GetWeakReference(aEditor);
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::Cleanup
+//
+//    Called by the editor when the editor is going away. This is important
+//    because we remove listeners. We do NOT clean up anything else in this
+//    function, because it can get called while DoSpellCheck is running!
+//
+//    Getting the style information there can cause DOM notifications to be
+//    flushed, which can cause editors to go away which will bring us here.
+//    We can not do anything that will cause DoSpellCheck to freak out.
+
+nsresult mozInlineSpellChecker::Cleanup(bool aDestroyingFrames)
+{
+  mNumWordsInSpellSelection = 0;
+  nsCOMPtr<nsISelection> spellCheckSelection;
+  nsresult rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
+  if (NS_FAILED(rv)) {
+    // Ensure we still unregister event listeners (but return a failure code)
+    UnregisterEventListeners();
+  } else {
+    if (!aDestroyingFrames) {
+      spellCheckSelection->RemoveAllRanges();
+    }
+
+    rv = UnregisterEventListeners();
+  }
+
+  // Notify ENDED observers now.  If we wait to notify as we normally do when
+  // these async operations finish, then in the meantime the editor may create
+  // another inline spell checker and cause more STARTED and ENDED
+  // notifications to be broadcast.  Interleaved notifications for the same
+  // editor but different inline spell checkers could easily confuse
+  // observers.  They may receive two consecutive STARTED notifications for
+  // example, which we guarantee will not happen.
+
+  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mEditor);
+  if (mPendingSpellCheck) {
+    // Cancel the pending editor spell checker initialization.
+    mPendingSpellCheck = nullptr;
+    mPendingInitEditorSpellCheckCallback->Cancel();
+    mPendingInitEditorSpellCheckCallback = nullptr;
+    ChangeNumPendingSpellChecks(-1, editor);
+  }
+
+  // Increment this token so that pending UpdateCurrentDictionary calls and
+  // scheduled spell checks are discarded when they finish.
+  mDisabledAsyncToken++;
+
+  if (mNumPendingUpdateCurrentDictionary > 0) {
+    // Account for pending UpdateCurrentDictionary calls.
+    ChangeNumPendingSpellChecks(-mNumPendingUpdateCurrentDictionary, editor);
+    mNumPendingUpdateCurrentDictionary = 0;
+  }
+  if (mNumPendingSpellChecks > 0) {
+    // If mNumPendingSpellChecks is still > 0 at this point, the remainder is
+    // pending scheduled spell checks.
+    ChangeNumPendingSpellChecks(-mNumPendingSpellChecks, editor);
+  }
+
+  mEditor = nullptr;
+  mFullSpellCheckScheduled = false;
+
+  return rv;
+}
+
+// mozInlineSpellChecker::CanEnableInlineSpellChecking
+//
+//    This function can be called to see if it seems likely that we can enable
+//    spellchecking before actually creating the InlineSpellChecking objects.
+//
+//    The problem is that we can't get the dictionary list without actually
+//    creating a whole bunch of spellchecking objects. This function tries to
+//    do that and caches the result so we don't have to keep allocating those
+//    objects if there are no dictionaries or spellchecking.
+//
+//    Whenever dictionaries are added or removed at runtime, this value must be
+//    updated before an observer notification is sent out about the change, to
+//    avoid editors getting a wrong cached result.
+
+bool // static
+mozInlineSpellChecker::CanEnableInlineSpellChecking()
+{
+  nsresult rv;
+  if (gCanEnableSpellChecking == SpellCheck_Uninitialized) {
+    gCanEnableSpellChecking = SpellCheck_NotAvailable;
+
+    nsCOMPtr<nsIEditorSpellCheck> spellchecker =
+      do_CreateInstance("@mozilla.org/editor/editorspellchecker;1", &rv);
+    NS_ENSURE_SUCCESS(rv, false);
+
+    bool canSpellCheck = false;
+    rv = spellchecker->CanSpellCheck(&canSpellCheck);
+    NS_ENSURE_SUCCESS(rv, false);
+
+    if (canSpellCheck)
+      gCanEnableSpellChecking = SpellCheck_Available;
+  }
+  return (gCanEnableSpellChecking == SpellCheck_Available);
+}
+
+void // static
+mozInlineSpellChecker::UpdateCanEnableInlineSpellChecking()
+{
+  gCanEnableSpellChecking = SpellCheck_Uninitialized;
+}
+
+// mozInlineSpellChecker::RegisterEventListeners
+//
+//    The inline spell checker listens to mouse events and keyboard navigation+ //    events.
+
+nsresult
+mozInlineSpellChecker::RegisterEventListeners()
+{
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);
+
+  editor->AddEditActionListener(this);
+
+  nsCOMPtr<nsIDOMDocument> doc;
+  nsresult rv = editor->GetDocument(getter_AddRefs(doc));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<EventTarget> piTarget = do_QueryInterface(doc, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  piTarget->AddEventListener(NS_LITERAL_STRING("blur"), this,
+                             true, false);
+  piTarget->AddEventListener(NS_LITERAL_STRING("click"), this,
+                             false, false);
+  piTarget->AddEventListener(NS_LITERAL_STRING("keypress"), this,
+                             false, false);
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::UnregisterEventListeners
+
+nsresult
+mozInlineSpellChecker::UnregisterEventListeners()
+{
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);
+
+  editor->RemoveEditActionListener(this);
+
+  nsCOMPtr<nsIDOMDocument> doc;
+  editor->GetDocument(getter_AddRefs(doc));
+  NS_ENSURE_TRUE(doc, NS_ERROR_NULL_POINTER);
+
+  nsCOMPtr<EventTarget> piTarget = do_QueryInterface(doc);
+  NS_ENSURE_TRUE(piTarget, NS_ERROR_NULL_POINTER);
+
+  piTarget->RemoveEventListener(NS_LITERAL_STRING("blur"), this, true);
+  piTarget->RemoveEventListener(NS_LITERAL_STRING("click"), this, false);
+  piTarget->RemoveEventListener(NS_LITERAL_STRING("keypress"), this, false);
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::GetEnableRealTimeSpell
+
+NS_IMETHODIMP
+mozInlineSpellChecker::GetEnableRealTimeSpell(bool* aEnabled)
+{
+  NS_ENSURE_ARG_POINTER(aEnabled);
+  *aEnabled = mSpellCheck != nullptr || mPendingSpellCheck != nullptr;
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::SetEnableRealTimeSpell
+
+NS_IMETHODIMP
+mozInlineSpellChecker::SetEnableRealTimeSpell(bool aEnabled)
+{
+  if (!aEnabled) {
+    mSpellCheck = nullptr;
+    return Cleanup(false);
+  }
+
+  if (mSpellCheck) {
+    // spellcheck the current contents. SpellCheckRange doesn't supply a created
+    // range to DoSpellCheck, which in our case is the entire range. But this
+    // optimization doesn't matter because there is nothing in the spellcheck
+    // selection when starting, which triggers a better optimization.
+    return SpellCheckRange(nullptr);
+  }
+
+  if (mPendingSpellCheck) {
+    // The editor spell checker is already being initialized.
+    return NS_OK;
+  }
+
+  mPendingSpellCheck =
+    do_CreateInstance("@mozilla.org/editor/editorspellchecker;1");
+  NS_ENSURE_STATE(mPendingSpellCheck);
+
+  nsCOMPtr<nsITextServicesFilter> filter =
+    do_CreateInstance("@mozilla.org/editor/txtsrvfiltermail;1");
+  if (!filter) {
+    mPendingSpellCheck = nullptr;
+    NS_ENSURE_STATE(filter);
+  }
+  mPendingSpellCheck->SetFilter(filter);
+
+  mPendingInitEditorSpellCheckCallback = new InitEditorSpellCheckCallback(this);
+  if (!mPendingInitEditorSpellCheckCallback) {
+    mPendingSpellCheck = nullptr;
+    NS_ENSURE_STATE(mPendingInitEditorSpellCheckCallback);
+  }
+
+  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mEditor);
+  nsresult rv = mPendingSpellCheck->InitSpellChecker(
+                  editor, false, mPendingInitEditorSpellCheckCallback);
+  if (NS_FAILED(rv)) {
+    mPendingSpellCheck = nullptr;
+    mPendingInitEditorSpellCheckCallback = nullptr;
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  ChangeNumPendingSpellChecks(1);
+
+  return NS_OK;
+}
+
+// Called when nsIEditorSpellCheck::InitSpellChecker completes.
+nsresult
+mozInlineSpellChecker::EditorSpellCheckInited()
+{
+  NS_ASSERTION(mPendingSpellCheck, "Spell check should be pending!");
+
+  // spell checking is enabled, register our event listeners to track navigation
+  RegisterEventListeners();
+
+  mSpellCheck = mPendingSpellCheck;
+  mPendingSpellCheck = nullptr;
+  mPendingInitEditorSpellCheckCallback = nullptr;
+  ChangeNumPendingSpellChecks(-1);
+
+  // spellcheck the current contents. SpellCheckRange doesn't supply a created
+  // range to DoSpellCheck, which in our case is the entire range. But this
+  // optimization doesn't matter because there is nothing in the spellcheck
+  // selection when starting, which triggers a better optimization.
+  return SpellCheckRange(nullptr);
+}
+
+// Changes the number of pending spell checks by the given delta.  If the number
+// becomes zero or nonzero, observers are notified.  See NotifyObservers for
+// info on the aEditor parameter.
+void
+mozInlineSpellChecker::ChangeNumPendingSpellChecks(int32_t aDelta,
+                                                   nsIEditor* aEditor)
+{
+  int8_t oldNumPending = mNumPendingSpellChecks;
+  mNumPendingSpellChecks += aDelta;
+  NS_ASSERTION(mNumPendingSpellChecks >= 0,
+               "Unbalanced ChangeNumPendingSpellChecks calls!");
+  if (oldNumPending == 0 && mNumPendingSpellChecks > 0) {
+    NotifyObservers(INLINESPELL_STARTED_TOPIC, aEditor);
+  } else if (oldNumPending > 0 && mNumPendingSpellChecks == 0) {
+    NotifyObservers(INLINESPELL_ENDED_TOPIC, aEditor);
+  }
+}
+
+// Broadcasts the given topic to observers.  aEditor is passed to observers if
+// nonnull; otherwise mEditor is passed.
+void
+mozInlineSpellChecker::NotifyObservers(const char* aTopic, nsIEditor* aEditor)
+{
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (!os)
+    return;
+  nsCOMPtr<nsIEditor> editor = aEditor;
+  if (!editor) {
+    editor = do_QueryReferent(mEditor);
+  }
+  os->NotifyObservers(editor, aTopic, nullptr);
+}
+
+// mozInlineSpellChecker::SpellCheckAfterEditorChange
+//
+//    Called by the editor when nearly anything happens to change the content.
+//
+//    The start and end positions specify a range for the thing that happened,
+//    but these are usually nullptr, even when you'd think they would be useful
+//    because you want the range (for example, pasting). We ignore them in
+//    this case.
+
+NS_IMETHODIMP
+mozInlineSpellChecker::SpellCheckAfterEditorChange(
+    int32_t aAction, nsISelection *aSelection,
+    nsIDOMNode *aPreviousSelectedNode, int32_t aPreviousSelectedOffset,
+    nsIDOMNode *aStartNode, int32_t aStartOffset,
+    nsIDOMNode *aEndNode, int32_t aEndOffset)
+{
+  nsresult rv;
+  NS_ENSURE_ARG_POINTER(aSelection);
+  if (!mSpellCheck)
+    return NS_OK; // disabling spell checking is not an error
+
+  // this means something has changed, and we never check the current word,
+  // therefore, we should spellcheck for subsequent caret navigations
+  mNeedsCheckAfterNavigation = true;
+
+  // the anchor node is the position of the caret
+  nsCOMPtr<nsIDOMNode> anchorNode;
+  rv = aSelection->GetAnchorNode(getter_AddRefs(anchorNode));
+  NS_ENSURE_SUCCESS(rv, rv);
+  int32_t anchorOffset;
+  rv = aSelection->GetAnchorOffset(&anchorOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mozInlineSpellStatus status(this);
+  rv = status.InitForEditorChange((EditAction)aAction,
+                                  anchorNode, anchorOffset,
+                                  aPreviousSelectedNode, aPreviousSelectedOffset,
+                                  aStartNode, aStartOffset,
+                                  aEndNode, aEndOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = ScheduleSpellCheck(status);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // remember the current caret position after every change
+  SaveCurrentSelectionPosition();
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::SpellCheckRange
+//
+//    Spellchecks all the words in the given range.
+//    Supply a nullptr range and this will check the entire editor.
+
+nsresult
+mozInlineSpellChecker::SpellCheckRange(nsIDOMRange* aRange)
+{
+  if (!mSpellCheck) {
+    NS_WARNING_ASSERTION(
+      mPendingSpellCheck,
+      "Trying to spellcheck, but checking seems to be disabled");
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  mozInlineSpellStatus status(this);
+  nsRange* range = static_cast<nsRange*>(aRange);
+  nsresult rv = status.InitForRange(range);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ScheduleSpellCheck(status);
+}
+
+// mozInlineSpellChecker::GetMisspelledWord
+
+NS_IMETHODIMP
+mozInlineSpellChecker::GetMisspelledWord(nsIDOMNode *aNode, int32_t aOffset,
+                                         nsIDOMRange **newword)
+{
+  NS_ENSURE_ARG_POINTER(aNode);
+  nsCOMPtr<nsISelection> spellCheckSelection;
+  nsresult res = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
+  NS_ENSURE_SUCCESS(res, res); 
+
+  return IsPointInSelection(spellCheckSelection, aNode, aOffset, newword);
+}
+
+// mozInlineSpellChecker::ReplaceWord
+
+NS_IMETHODIMP
+mozInlineSpellChecker::ReplaceWord(nsIDOMNode *aNode, int32_t aOffset,
+                                   const nsAString &newword)
+{
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(newword.Length() != 0, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsIDOMRange> range;
+  nsresult res = GetMisspelledWord(aNode, aOffset, getter_AddRefs(range));
+  NS_ENSURE_SUCCESS(res, res); 
+
+  if (range)
+  {
+    // This range was retrieved from the spellchecker selection. As
+    // ranges cannot be shared between selections, we must clone it
+    // before adding it to the editor's selection.
+    nsCOMPtr<nsIDOMRange> editorRange;
+    res = range->CloneRange(getter_AddRefs(editorRange));
+    NS_ENSURE_SUCCESS(res, res);
+
+    AutoPlaceHolderBatch phb(editor, nullptr);
+  
+    nsCOMPtr<nsISelection> selection;
+    res = editor->GetSelection(getter_AddRefs(selection));
+    NS_ENSURE_SUCCESS(res, res);
+    selection->RemoveAllRanges();
+    selection->AddRange(editorRange);
+    editor->DeleteSelection(nsIEditor::eNone, nsIEditor::eStrip);
+
+    nsCOMPtr<nsIPlaintextEditor> textEditor(do_QueryReferent(mEditor));
+    if (textEditor)
+      textEditor->InsertText(newword);
+  }
+
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::AddWordToDictionary
+
+NS_IMETHODIMP
+mozInlineSpellChecker::AddWordToDictionary(const nsAString &word)
+{
+  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);
+
+  nsAutoString wordstr(word);
+  nsresult rv = mSpellCheck->AddWordToDictionary(wordstr.get());
+  NS_ENSURE_SUCCESS(rv, rv); 
+
+  mozInlineSpellStatus status(this);
+  rv = status.InitForSelection();
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ScheduleSpellCheck(status);
+}
+
+//  mozInlineSpellChecker::RemoveWordFromDictionary
+
+NS_IMETHODIMP
+mozInlineSpellChecker::RemoveWordFromDictionary(const nsAString &word)
+{
+  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);
+
+  nsAutoString wordstr(word);
+  nsresult rv = mSpellCheck->RemoveWordFromDictionary(wordstr.get());
+  NS_ENSURE_SUCCESS(rv, rv); 
+  
+  mozInlineSpellStatus status(this);
+  rv = status.InitForRange(nullptr);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ScheduleSpellCheck(status);
+}
+
+// mozInlineSpellChecker::IgnoreWord
+
+NS_IMETHODIMP
+mozInlineSpellChecker::IgnoreWord(const nsAString &word)
+{
+  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);
+
+  nsAutoString wordstr(word);
+  nsresult rv = mSpellCheck->IgnoreWordAllOccurrences(wordstr.get());
+  NS_ENSURE_SUCCESS(rv, rv); 
+
+  mozInlineSpellStatus status(this);
+  rv = status.InitForSelection();
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ScheduleSpellCheck(status);
+}
+
+// mozInlineSpellChecker::IgnoreWords
+
+NS_IMETHODIMP
+mozInlineSpellChecker::IgnoreWords(const char16_t **aWordsToIgnore,
+                                   uint32_t aCount)
+{
+  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);
+
+  // add each word to the ignore list and then recheck the document
+  for (uint32_t index = 0; index < aCount; index++)
+    mSpellCheck->IgnoreWordAllOccurrences(aWordsToIgnore[index]);
+
+  mozInlineSpellStatus status(this);
+  nsresult rv = status.InitForSelection();
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ScheduleSpellCheck(status);
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillCreateNode(const nsAString & aTag, nsIDOMNode *aParent, int32_t aPosition)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidCreateNode(const nsAString & aTag, nsIDOMNode *aNode, nsIDOMNode *aParent,
+                                                   int32_t aPosition, nsresult aResult)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillInsertNode(nsIDOMNode *aNode, nsIDOMNode *aParent,
+                                                    int32_t aPosition)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidInsertNode(nsIDOMNode *aNode, nsIDOMNode *aParent,
+                                                   int32_t aPosition, nsresult aResult)
+{
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillDeleteNode(nsIDOMNode *aChild)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidDeleteNode(nsIDOMNode *aChild, nsresult aResult)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillSplitNode(nsIDOMNode *aExistingRightNode, int32_t aOffset)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+mozInlineSpellChecker::DidSplitNode(nsIDOMNode *aExistingRightNode,
+                                    int32_t aOffset,
+                                    nsIDOMNode *aNewLeftNode, nsresult aResult)
+{
+  return SpellCheckBetweenNodes(aNewLeftNode, 0, aNewLeftNode, 0);
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillJoinNodes(nsIDOMNode *aLeftNode, nsIDOMNode *aRightNode, nsIDOMNode *aParent)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidJoinNodes(nsIDOMNode *aLeftNode, nsIDOMNode *aRightNode, 
+                                                  nsIDOMNode *aParent, nsresult aResult)
+{
+  return SpellCheckBetweenNodes(aRightNode, 0, aRightNode, 0);
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillInsertText(nsIDOMCharacterData *aTextNode, int32_t aOffset, const nsAString & aString)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidInsertText(nsIDOMCharacterData *aTextNode, int32_t aOffset,
+                                                   const nsAString & aString, nsresult aResult)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillDeleteText(nsIDOMCharacterData *aTextNode, int32_t aOffset, int32_t aLength)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidDeleteText(nsIDOMCharacterData *aTextNode, int32_t aOffset, int32_t aLength, nsresult aResult)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::WillDeleteSelection(nsISelection *aSelection)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::DidDeleteSelection(nsISelection *aSelection)
+{
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::MakeSpellCheckRange
+//
+//    Given begin and end positions, this function constructs a range as
+//    required for ScheduleSpellCheck. If the start and end nodes are nullptr,
+//    then the entire range will be selected, and you can supply -1 as the
+//    offset to the end range to select all of that node.
+//
+//    If the resulting range would be empty, nullptr is put into *aRange and the
+//    function succeeds.
+
+nsresult
+mozInlineSpellChecker::MakeSpellCheckRange(
+    nsIDOMNode* aStartNode, int32_t aStartOffset,
+    nsIDOMNode* aEndNode, int32_t aEndOffset,
+    nsRange** aRange)
+{
+  nsresult rv;
+  *aRange = nullptr;
+
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);
+
+  nsCOMPtr<nsIDOMDocument> doc;
+  rv = editor->GetDocument(getter_AddRefs(doc));
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsIDOMRange> range;
+  rv = doc->CreateRange(getter_AddRefs(range));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // possibly use full range of the editor
+  nsCOMPtr<nsIDOMElement> rootElem;
+  if (! aStartNode || ! aEndNode) {
+    rv = editor->GetRootElement(getter_AddRefs(rootElem));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    aStartNode = rootElem;
+    aStartOffset = 0;
+
+    aEndNode = rootElem;
+    aEndOffset = -1;
+  }
+
+  if (aEndOffset == -1) {
+    nsCOMPtr<nsIDOMNodeList> childNodes;
+    rv = aEndNode->GetChildNodes(getter_AddRefs(childNodes));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    uint32_t childCount;
+    rv = childNodes->GetLength(&childCount);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    aEndOffset = childCount;
+  }
+
+  // sometimes we are are requested to check an empty range (possibly an empty
+  // document). This will result in assertions later.
+  if (aStartNode == aEndNode && aStartOffset == aEndOffset)
+    return NS_OK;
+
+  rv = range->SetStart(aStartNode, aStartOffset);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (aEndOffset)
+    rv = range->SetEnd(aEndNode, aEndOffset);
+  else
+    rv = range->SetEndAfter(aEndNode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aRange = static_cast<nsRange*>(range.forget().take());
+  return NS_OK;
+}
+
+nsresult
+mozInlineSpellChecker::SpellCheckBetweenNodes(nsIDOMNode *aStartNode,
+                                              int32_t aStartOffset,
+                                              nsIDOMNode *aEndNode,
+                                              int32_t aEndOffset)
+{
+  RefPtr<nsRange> range;
+  nsresult rv = MakeSpellCheckRange(aStartNode, aStartOffset,
+                                    aEndNode, aEndOffset,
+                                    getter_AddRefs(range));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (! range)
+    return NS_OK; // range is empty: nothing to do
+
+  mozInlineSpellStatus status(this);
+  rv = status.InitForRange(range);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ScheduleSpellCheck(status);
+}
+
+// mozInlineSpellChecker::ShouldSpellCheckNode
+//
+//    There are certain conditions when we don't want to spell check a node. In
+//    particular quotations, moz signatures, etc. This routine returns false
+//    for these cases.
+
+bool
+mozInlineSpellChecker::ShouldSpellCheckNode(nsIEditor* aEditor,
+                                            nsINode *aNode)
+{
+  MOZ_ASSERT(aNode);
+  if (!aNode->IsContent())
+    return true;
+
+  nsIContent *content = aNode->AsContent();
+
+  uint32_t flags;
+  aEditor->GetFlags(&flags);
+  if (flags & nsIPlaintextEditor::eEditorMailMask) {
+    nsIContent *parent = content->GetParent();
+    while (parent) {
+      if (parent->IsHTMLElement(nsGkAtoms::blockquote) &&
+          parent->AttrValueIs(kNameSpaceID_None,
+                              nsGkAtoms::type,
+                              nsGkAtoms::cite,
+                              eIgnoreCase)) {
+        return false;
+      }
+      if (parent->IsHTMLElement(nsGkAtoms::pre) &&
+          parent->AttrValueIs(kNameSpaceID_None,
+                              nsGkAtoms::_class,
+                              nsGkAtoms::mozsignature,
+                              eIgnoreCase)) {
+        return false;
+      }
+
+      parent = parent->GetParent();
+    }
+  } else {
+    // Check spelling only if the node is editable, and GetSpellcheck() is true
+    // on the nearest HTMLElement ancestor.
+    if (!content->IsEditable()) {
+      return false;
+    }
+
+    // Make sure that we can always turn on spell checking for inputs/textareas.
+    // Note that because of the previous check, at this point we know that the
+    // node is editable.
+    if (content->IsInAnonymousSubtree()) {
+      nsIContent *node = content->GetParent();
+      while (node && node->IsInNativeAnonymousSubtree()) {
+        node = node->GetParent();
+      }
+      nsCOMPtr<nsITextControlElement> textControl = do_QueryInterface(node);
+      if (textControl) {
+        return true;
+      }
+    }
+
+    // Get HTML element ancestor (might be aNode itself, although probably that
+    // has to be a text node in real life here)
+    nsIContent *parent = content;
+    while (!parent->IsHTMLElement()) {
+      parent = parent->GetParent();
+      if (!parent) {
+        return true;
+      }
+    }
+
+    // See if it's spellcheckable
+    return static_cast<nsGenericHTMLElement *>(parent)->Spellcheck();
+  }
+
+  return true;
+}
+
+// mozInlineSpellChecker::ScheduleSpellCheck
+//
+//    This is called by code to do the actual spellchecking. We will set up
+//    the proper structures for calls to DoSpellCheck.
+
+nsresult
+mozInlineSpellChecker::ScheduleSpellCheck(const mozInlineSpellStatus& aStatus)
+{
+  if (mFullSpellCheckScheduled) {
+    // Just ignore this; we're going to spell-check everything anyway
+    return NS_OK;
+  }
+
+  RefPtr<mozInlineSpellResume> resume =
+    new mozInlineSpellResume(aStatus, mDisabledAsyncToken);
+  NS_ENSURE_TRUE(resume, NS_ERROR_OUT_OF_MEMORY);
+
+  nsresult rv = resume->Post();
+  if (NS_SUCCEEDED(rv)) {
+    if (aStatus.IsFullSpellCheck()) {
+      // We're going to check everything.  Suppress further spell-check attempts
+      // until that happens.
+      mFullSpellCheckScheduled = true;
+    }
+    ChangeNumPendingSpellChecks(1);
+  }
+  return rv;
+}
+
+// mozInlineSpellChecker::DoSpellCheckSelection
+//
+//    Called to re-check all misspelled words. We iterate over all ranges in
+//    the selection and call DoSpellCheck on them. This is used when a word
+//    is ignored or added to the dictionary: all instances of that word should
+//    be removed from the selection.
+//
+//    FIXME-PERFORMANCE: This takes as long as it takes and is not resumable.
+//    Typically, checking this small amount of text is relatively fast, but
+//    for large numbers of words, a lag may be noticeable.
+
+nsresult
+mozInlineSpellChecker::DoSpellCheckSelection(mozInlineSpellWordUtil& aWordUtil,
+                                             Selection* aSpellCheckSelection,
+                                             mozInlineSpellStatus* aStatus)
+{
+  nsresult rv;
+
+  // clear out mNumWordsInSpellSelection since we'll be rebuilding the ranges.
+  mNumWordsInSpellSelection = 0;
+
+  // Since we could be modifying the ranges for the spellCheckSelection while
+  // looping on the spell check selection, keep a separate array of range
+  // elements inside the selection
+  nsTArray<RefPtr<nsRange>> ranges;
+
+  int32_t count = aSpellCheckSelection->RangeCount();
+
+  for (int32_t idx = 0; idx < count; idx++) {
+    nsRange *range = aSpellCheckSelection->GetRangeAt(idx);
+    if (range) {
+      ranges.AppendElement(range);
+    }
+  }
+
+  // We have saved the ranges above. Clearing the spellcheck selection here
+  // isn't necessary (rechecking each word will modify it as necessary) but
+  // provides better performance. By ensuring that no ranges need to be
+  // removed in DoSpellCheck, we can save checking range inclusion which is
+  // slow.
+  aSpellCheckSelection->RemoveAllRanges();
+
+  // We use this state object for all calls, and just update its range. Note
+  // that we don't need to call FinishInit since we will be filling in the
+  // necessary information.
+  mozInlineSpellStatus status(this);
+  rv = status.InitForRange(nullptr);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool doneChecking;
+  for (int32_t idx = 0; idx < count; idx++) {
+    // We can consider this word as "added" since we know it has no spell
+    // check range over it that needs to be deleted. All the old ranges
+    // were cleared above. We also need to clear the word count so that we
+    // check all words instead of stopping early.
+    status.mRange = ranges[idx];
+    rv = DoSpellCheck(aWordUtil, aSpellCheckSelection, &status,
+                      &doneChecking);
+    NS_ENSURE_SUCCESS(rv, rv);
+    MOZ_ASSERT(doneChecking,
+               "We gave the spellchecker one word, but it didn't finish checking?!?!");
+
+    status.mWordCount = 0;
+  }
+
+  return NS_OK;
+}
+
+// mozInlineSpellChecker::DoSpellCheck
+//
+//    This function checks words intersecting the given range, excluding those
+//    inside mStatus->mNoCheckRange (can be nullptr). Words inside aNoCheckRange
+//    will have any spell selection removed (this is used to hide the
+//    underlining for the word that the caret is in). aNoCheckRange should be
+//    on word boundaries.
+//
+//    mResume->mCreatedRange is a possibly nullptr range of new text that was
+//    inserted.  Inside this range, we don't bother to check whether things are
+//    inside the spellcheck selection, which speeds up large paste operations
+//    considerably.
+//
+//    Normal case when editing text by typing
+//       h e l l o   w o r k d   h o w   a r e   y o u
+//                            ^ caret
+//                   [-------] mRange
+//                   [-------] mNoCheckRange
+//      -> does nothing (range is the same as the no check range)
+//
+//    Case when pasting:
+//             [---------- pasted text ----------]
+//       h e l l o   w o r k d   h o w   a r e   y o u
+//                                                ^ caret
+//                                               [---] aNoCheckRange
+//      -> recheck all words in range except those in aNoCheckRange
+//
+//    If checking is complete, *aDoneChecking will be set. If there is more
+//    but we ran out of time, this will be false and the range will be
+//    updated with the stuff that still needs checking.
+
+nsresult mozInlineSpellChecker::DoSpellCheck(mozInlineSpellWordUtil& aWordUtil,
+                                             Selection *aSpellCheckSelection,
+                                             mozInlineSpellStatus* aStatus,
+                                             bool* aDoneChecking)
+{
+  *aDoneChecking = true;
+
+  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);
+
+  // get the editor for ShouldSpellCheckNode, this may fail in reasonable
+  // circumstances since the editor could have gone away
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  if (! editor)
+    return NS_ERROR_FAILURE;
+
+  if (aStatus->mRange->Collapsed())
+    return NS_OK;
+
+  // see if the selection has any ranges, if not, then we can optimize checking
+  // range inclusion later (we have no ranges when we are initially checking or
+  // when there are no misspelled words yet).
+  int32_t originalRangeCount = aSpellCheckSelection->RangeCount();
+
+  // set the starting DOM position to be the beginning of our range
+  {
+    // Scope for the node/offset pairs here so they don't get
+    // accidentally used later
+    nsINode* beginNode = aStatus->mRange->GetStartParent();
+    int32_t beginOffset = aStatus->mRange->StartOffset();
+    nsINode* endNode = aStatus->mRange->GetEndParent();
+    int32_t endOffset = aStatus->mRange->EndOffset();
+
+    // Now check that we're still looking at a range that's under
+    // aWordUtil.GetRootNode()
+    nsINode* rootNode = aWordUtil.GetRootNode();
+    if (!nsContentUtils::ContentIsDescendantOf(beginNode, rootNode) ||
+        !nsContentUtils::ContentIsDescendantOf(endNode, rootNode)) {
+      // Just bail out and don't try to spell-check this
+      return NS_OK;
+    }
+
+    aWordUtil.SetEnd(endNode, endOffset);
+    aWordUtil.SetPosition(beginNode, beginOffset);
+  }
+
+  // aWordUtil.SetPosition flushes pending notifications, check editor again.
+  // XXX Uhhh, *we're* holding a strong ref to the editor.
+  editor = do_QueryReferent(mEditor);
+  if (! editor)
+    return NS_ERROR_FAILURE;
+
+  int32_t wordsSinceTimeCheck = 0;
+  PRTime beginTime = PR_Now();
+
+  nsAutoString wordText;
+  RefPtr<nsRange> wordRange;
+  bool dontCheckWord;
+  while (NS_SUCCEEDED(aWordUtil.GetNextWord(wordText,
+                                            getter_AddRefs(wordRange),
+                                            &dontCheckWord)) &&
+         wordRange) {
+    wordsSinceTimeCheck++;
+
+    // get the range for the current word.
+    nsINode *beginNode;
+    nsINode *endNode;
+    int32_t beginOffset, endOffset;
+
+    ErrorResult erv;
+    beginNode = wordRange->GetStartContainer(erv);
+    endNode = wordRange->GetEndContainer(erv);
+    beginOffset = wordRange->GetStartOffset(erv);
+    endOffset = wordRange->GetEndOffset(erv);
+
+#ifdef DEBUG_INLINESPELL
+    printf("->Got word \"%s\"", NS_ConvertUTF16toUTF8(wordText).get());
+    if (dontCheckWord)
+      printf(" (not checking)");
+    printf("\n");
+#endif
+
+    // see if there is a spellcheck range that already intersects the word
+    // and remove it. We only need to remove old ranges, so don't bother if
+    // there were no ranges when we started out.
+    if (originalRangeCount > 0) {
+      // likewise, if this word is inside new text, we won't bother testing
+      if (!aStatus->mCreatedRange ||
+          !aStatus->mCreatedRange->IsPointInRange(*beginNode, beginOffset, erv)) {
+        nsTArray<RefPtr<nsRange>> ranges;
+        aSpellCheckSelection->GetRangesForInterval(*beginNode, beginOffset,
+                                                   *endNode, endOffset,
+                                                   true, ranges, erv);
+        ENSURE_SUCCESS(erv, erv.StealNSResult());
+        for (uint32_t i = 0; i < ranges.Length(); i++)
+          RemoveRange(aSpellCheckSelection, ranges[i]);
+      }
+    }
+
+    // some words are special and don't need checking
+    if (dontCheckWord)
+      continue;
+
+    // some nodes we don't spellcheck
+    if (!ShouldSpellCheckNode(editor, beginNode))
+      continue;
+
+    // Don't check spelling if we're inside the noCheckRange. This needs to
+    // be done after we clear any old selection because the excluded word
+    // might have been previously marked.
+    //
+    // We do a simple check to see if the beginning of our word is in the
+    // exclusion range. Because the exclusion range is a multiple of a word,
+    // this is sufficient.
+    if (aStatus->mNoCheckRange &&
+        aStatus->mNoCheckRange->IsPointInRange(*beginNode, beginOffset, erv)) {
+      continue;
+    }
+
+    // check spelling and add to selection if misspelled
+    bool isMisspelled;
+    aWordUtil.NormalizeWord(wordText);
+    nsresult rv = mSpellCheck->CheckCurrentWordNoSuggest(wordText.get(), &isMisspelled);
+    if (NS_FAILED(rv))
+      continue;
+
+    if (isMisspelled) {
+      // misspelled words count extra toward the max
+      wordsSinceTimeCheck += MISSPELLED_WORD_COUNT_PENALTY;
+      AddRange(aSpellCheckSelection, wordRange);
+
+      aStatus->mWordCount ++;
+      if (aStatus->mWordCount >= mMaxMisspellingsPerCheck ||
+          SpellCheckSelectionIsFull())
+        break;
+    }
+
+    // see if we've run out of time, only check every N words for perf
+    if (wordsSinceTimeCheck >= INLINESPELL_TIMEOUT_CHECK_FREQUENCY) {
+      wordsSinceTimeCheck = 0;
+      if (PR_Now() > PRTime(beginTime + INLINESPELL_CHECK_TIMEOUT * PR_USEC_PER_MSEC)) {
+        // stop checking, our time limit has been exceeded
+
+        // move the range to encompass the stuff that needs checking
+        rv = aStatus->mRange->SetStart(endNode, endOffset);
+        if (NS_FAILED(rv)) {
+          // The range might be unhappy because the beginning is after the
+          // end. This is possible when the requested end was in the middle
+          // of a word, just ignore this situation and assume we're done.
+          return NS_OK;
+        }
+        *aDoneChecking = false;
+        return NS_OK;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+// An RAII helper that calls ChangeNumPendingSpellChecks on destruction.
+class AutoChangeNumPendingSpellChecks
+{
+public:
+  AutoChangeNumPendingSpellChecks(mozInlineSpellChecker* aSpellChecker,
+                                  int32_t aDelta)
+    : mSpellChecker(aSpellChecker), mDelta(aDelta) {}
+
+  ~AutoChangeNumPendingSpellChecks()
+  {
+    mSpellChecker->ChangeNumPendingSpellChecks(mDelta);
+  }
+
+private:
+  RefPtr<mozInlineSpellChecker> mSpellChecker;
+  int32_t mDelta;
+};
+
+// mozInlineSpellChecker::ResumeCheck
+//
+//    Called by the resume event when it fires. We will try to pick up where
+//    the last resume left off.
+
+nsresult
+mozInlineSpellChecker::ResumeCheck(mozInlineSpellStatus* aStatus)
+{
+  // Observers should be notified that spell check has ended only after spell
+  // check is done below, but since there are many early returns in this method
+  // and the number of pending spell checks must be decremented regardless of
+  // whether the spell check actually happens, use this RAII object.
+  AutoChangeNumPendingSpellChecks autoChangeNumPending(this, -1);
+
+  if (aStatus->IsFullSpellCheck()) {
+    // Allow posting new spellcheck resume events from inside
+    // ResumeCheck, now that we're actually firing.
+    NS_ASSERTION(mFullSpellCheckScheduled,
+                 "How could this be false?  The full spell check is "
+                 "calling us!!");
+    mFullSpellCheckScheduled = false;
+  }
+
+  if (! mSpellCheck)
+    return NS_OK; // spell checking has been turned off
+
+  nsCOMPtr<nsIEditor> editor = do_QueryReferent(mEditor);
+  if (! editor)
+    return NS_OK; // editor is gone
+
+  mozInlineSpellWordUtil wordUtil;
+  nsresult rv = wordUtil.Init(mEditor);
+  if (NS_FAILED(rv))
+    return NS_OK; // editor doesn't like us, don't assert
+
+  nsCOMPtr<nsISelection> spellCheckSelectionRef;
+  rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelectionRef));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  auto spellCheckSelection =
+    static_cast<Selection *>(spellCheckSelectionRef.get());
+
+  nsAutoString currentDictionary;
+  rv = mSpellCheck->GetCurrentDictionary(currentDictionary);
+  if (NS_FAILED(rv)) {
+    // no active dictionary
+    int32_t count = spellCheckSelection->RangeCount();
+    for (int32_t index = count - 1; index >= 0; index--) {
+      nsRange *checkRange = spellCheckSelection->GetRangeAt(index);
+      if (checkRange) {
+        RemoveRange(spellCheckSelection, checkRange);
+      }
+    }
+    return NS_OK;
+  }
+
+  CleanupRangesInSelection(spellCheckSelection);
+
+  rv = aStatus->FinishInitOnEvent(wordUtil);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (! aStatus->mRange)
+    return NS_OK; // empty range, nothing to do
+
+  bool doneChecking = true;
+  if (aStatus->mOp == mozInlineSpellStatus::eOpSelection)
+    rv = DoSpellCheckSelection(wordUtil, spellCheckSelection, aStatus);
+  else
+    rv = DoSpellCheck(wordUtil, spellCheckSelection, aStatus, &doneChecking);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (! doneChecking)
+    rv = ScheduleSpellCheck(*aStatus);
+  return rv;
+}
+
+// mozInlineSpellChecker::IsPointInSelection
+//
+//    Determines if a given (node,offset) point is inside the given
+//    selection. If so, the specific range of the selection that
+//    intersects is places in *aRange. (There may be multiple disjoint
+//    ranges in a selection.)
+//
+//    If there is no intersection, *aRange will be nullptr.
+
+nsresult
+mozInlineSpellChecker::IsPointInSelection(nsISelection *aSelection,
+                                          nsIDOMNode *aNode,
+                                          int32_t aOffset,
+                                          nsIDOMRange **aRange)
+{
+  *aRange = nullptr;
+
+  nsCOMPtr<nsISelectionPrivate> privSel(do_QueryInterface(aSelection));
+
+  nsTArray<nsRange*> ranges;
+  nsCOMPtr<nsINode> node = do_QueryInterface(aNode);
+  nsresult rv = privSel->GetRangesForIntervalArray(node, aOffset, node, aOffset,
+                                                   true, &ranges);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (ranges.Length() == 0)
+    return NS_OK; // no matches
+
+  // there may be more than one range returned, and we don't know what do
+  // do with that, so just get the first one
+  NS_ADDREF(*aRange = ranges[0]);
+  return NS_OK;
+}
+
+nsresult
+mozInlineSpellChecker::CleanupRangesInSelection(Selection *aSelection)
+{
+  // integrity check - remove ranges that have collapsed to nothing. This
+  // can happen if the node containing a highlighted word was removed.
+  if (!aSelection)
+    return NS_ERROR_FAILURE;
+
+  int32_t count = aSelection->RangeCount();
+
+  for (int32_t index = 0; index < count; index++)
+  {
+    nsRange *checkRange = aSelection->GetRangeAt(index);
+    if (checkRange)
+    {
+      if (checkRange->Collapsed())
+      {
+        RemoveRange(aSelection, checkRange);
+        index--;
+        count--;
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+
+// mozInlineSpellChecker::RemoveRange
+//
+//    For performance reasons, we have an upper bound on the number of word
+//    ranges  in the spell check selection. When removing a range from the
+//    selection, we need to decrement mNumWordsInSpellSelection
+
+nsresult
+mozInlineSpellChecker::RemoveRange(Selection *aSpellCheckSelection,
+                                   nsRange *aRange)
+{
+  NS_ENSURE_ARG_POINTER(aSpellCheckSelection);
+  NS_ENSURE_ARG_POINTER(aRange);
+
+  ErrorResult rv;
+  aSpellCheckSelection->RemoveRange(*aRange, rv);
+  if (!rv.Failed() && mNumWordsInSpellSelection)
+    mNumWordsInSpellSelection--;
+
+  return rv.StealNSResult();
+}
+
+
+// mozInlineSpellChecker::AddRange
+//
+//    For performance reasons, we have an upper bound on the number of word
+//    ranges we'll add to the spell check selection. Once we reach that upper
+//    bound, stop adding the ranges
+
+nsresult
+mozInlineSpellChecker::AddRange(nsISelection* aSpellCheckSelection,
+                                nsIDOMRange* aRange)
+{
+  NS_ENSURE_ARG_POINTER(aSpellCheckSelection);
+  NS_ENSURE_ARG_POINTER(aRange);
+
+  nsresult rv = NS_OK;
+
+  if (!SpellCheckSelectionIsFull())
+  {
+    rv = aSpellCheckSelection->AddRange(aRange);
+    if (NS_SUCCEEDED(rv))
+      mNumWordsInSpellSelection++;
+  }
+
+  return rv;
+}
+
+nsresult mozInlineSpellChecker::GetSpellCheckSelection(nsISelection ** aSpellCheckSelection)
+{ 
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);
+
+  nsCOMPtr<nsISelectionController> selcon;
+  nsresult rv = editor->GetSelectionController(getter_AddRefs(selcon));
+  NS_ENSURE_SUCCESS(rv, rv); 
+
+  return selcon->GetSelection(nsISelectionController::SELECTION_SPELLCHECK, aSpellCheckSelection);
+}
+
+nsresult mozInlineSpellChecker::SaveCurrentSelectionPosition()
+{
+  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
+  NS_ENSURE_TRUE(editor, NS_OK);
+
+  // figure out the old caret position based on the current selection
+  nsCOMPtr<nsISelection> selection;
+  nsresult rv = editor->GetSelection(getter_AddRefs(selection));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = selection->GetFocusNode(getter_AddRefs(mCurrentSelectionAnchorNode));
+  NS_ENSURE_SUCCESS(rv, rv);
+  
+  selection->GetFocusOffset(&mCurrentSelectionOffset);
+
+  return NS_OK;
+}
+
+// This is a copy of nsContentUtils::ContentIsDescendantOf. Another crime
+// for XPCOM's rap sheet
+bool // static
+ContentIsDescendantOf(nsINode* aPossibleDescendant,
+                      nsINode* aPossibleAncestor)
+{
+  NS_PRECONDITION(aPossibleDescendant, "The possible descendant is null!");
+  NS_PRECONDITION(aPossibleAncestor, "The possible ancestor is null!");
+
+  do {
+    if (aPossibleDescendant == aPossibleAncestor)
+      return true;
+    aPossibleDescendant = aPossibleDescendant->GetParentNode();
+  } while (aPossibleDescendant);
+
+  return false;
+}
+
+// mozInlineSpellChecker::HandleNavigationEvent
+//
+//    Acts upon mouse clicks and keyboard navigation changes, spell checking
+//    the previous word if the new navigation location moves us to another
+//    word.
+//
+//    This is complicated by the fact that our mouse events are happening after
+//    selection has been changed to account for the mouse click. But keyboard
+//    events are happening before the caret selection has changed. Working
+//    around this by letting keyboard events setting forceWordSpellCheck to
+//    true. aNewPositionOffset also tries to work around this for the
+//    DOM_VK_RIGHT and DOM_VK_LEFT cases.
+
+nsresult
+mozInlineSpellChecker::HandleNavigationEvent(bool aForceWordSpellCheck,
+                                             int32_t aNewPositionOffset)
+{
+  nsresult rv;
+
+  // If we already handled the navigation event and there is no possibility
+  // anything has changed since then, we don't have to do anything. This
+  // optimization makes a noticeable difference when you hold down a navigation
+  // key like Page Down.
+  if (! mNeedsCheckAfterNavigation)
+    return NS_OK;
+
+  nsCOMPtr<nsIDOMNode> currentAnchorNode = mCurrentSelectionAnchorNode;
+  int32_t currentAnchorOffset = mCurrentSelectionOffset;
+
+  // now remember the new focus position resulting from the event
+  rv = SaveCurrentSelectionPosition();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool shouldPost;
+  mozInlineSpellStatus status(this);
+  rv = status.InitForNavigation(aForceWordSpellCheck, aNewPositionOffset,
+                                currentAnchorNode, currentAnchorOffset,
+                                mCurrentSelectionAnchorNode, mCurrentSelectionOffset,
+                                &shouldPost);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (shouldPost) {
+    rv = ScheduleSpellCheck(status);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP mozInlineSpellChecker::HandleEvent(nsIDOMEvent* aEvent)
+{
+  nsAutoString eventType;
+  aEvent->GetType(eventType);
+
+  if (eventType.EqualsLiteral("blur")) {
+    return Blur(aEvent);
+  }
+  if (eventType.EqualsLiteral("click")) {
+    return MouseClick(aEvent);
+  }
+  if (eventType.EqualsLiteral("keypress")) {
+    return KeyPress(aEvent);
+  }
+
+  return NS_OK;
+}
+
+nsresult mozInlineSpellChecker::Blur(nsIDOMEvent* aEvent)
+{
+  // force spellcheck on blur, for instance when tabbing out of a textbox
+  HandleNavigationEvent(true);
+  return NS_OK;
+}
+
+nsresult mozInlineSpellChecker::MouseClick(nsIDOMEvent *aMouseEvent)
+{
+  nsCOMPtr<nsIDOMMouseEvent>mouseEvent = do_QueryInterface(aMouseEvent);
+  NS_ENSURE_TRUE(mouseEvent, NS_OK);
+
+  // ignore any errors from HandleNavigationEvent as we don't want to prevent 
+  // anyone else from seeing this event.
+  int16_t button;
+  mouseEvent->GetButton(&button);
+  HandleNavigationEvent(button != 0);
+  return NS_OK;
+}
+
+nsresult mozInlineSpellChecker::KeyPress(nsIDOMEvent* aKeyEvent)
+{
+  nsCOMPtr<nsIDOMKeyEvent>keyEvent = do_QueryInterface(aKeyEvent);
+  NS_ENSURE_TRUE(keyEvent, NS_OK);
+
+  uint32_t keyCode;
+  keyEvent->GetKeyCode(&keyCode);
+
+  // we only care about navigation keys that moved selection 
+  switch (keyCode)
+  {
+    case nsIDOMKeyEvent::DOM_VK_RIGHT:
+    case nsIDOMKeyEvent::DOM_VK_LEFT:
+      HandleNavigationEvent(false, keyCode == nsIDOMKeyEvent::DOM_VK_RIGHT ? 1 : -1);
+      break;
+    case nsIDOMKeyEvent::DOM_VK_UP:
+    case nsIDOMKeyEvent::DOM_VK_DOWN:
+    case nsIDOMKeyEvent::DOM_VK_HOME:
+    case nsIDOMKeyEvent::DOM_VK_END:
+    case nsIDOMKeyEvent::DOM_VK_PAGE_UP:
+    case nsIDOMKeyEvent::DOM_VK_PAGE_DOWN:
+      HandleNavigationEvent(true /* force a spelling correction */);
+      break;
+  }
+
+  return NS_OK;
+}
+
+// Used as the nsIEditorSpellCheck::UpdateCurrentDictionary callback.
+class UpdateCurrentDictionaryCallback final : public nsIEditorSpellCheckCallback
+{
+public:
+  NS_DECL_ISUPPORTS
+
+  explicit UpdateCurrentDictionaryCallback(mozInlineSpellChecker* aSpellChecker,
+                                           uint32_t aDisabledAsyncToken)
+    : mSpellChecker(aSpellChecker), mDisabledAsyncToken(aDisabledAsyncToken) {}
+
+  NS_IMETHOD EditorSpellCheckDone() override
+  {
+    // Ignore this callback if SetEnableRealTimeSpell(false) was called after
+    // the UpdateCurrentDictionary call that triggered it.
+    return mSpellChecker->mDisabledAsyncToken > mDisabledAsyncToken ?
+           NS_OK :
+           mSpellChecker->CurrentDictionaryUpdated();
+  }
+
+private:
+  ~UpdateCurrentDictionaryCallback() {}
+
+  RefPtr<mozInlineSpellChecker> mSpellChecker;
+  uint32_t mDisabledAsyncToken;
+};
+NS_IMPL_ISUPPORTS(UpdateCurrentDictionaryCallback, nsIEditorSpellCheckCallback)
+
+NS_IMETHODIMP mozInlineSpellChecker::UpdateCurrentDictionary()
+{
+  // mSpellCheck is null and mPendingSpellCheck is nonnull while the spell
+  // checker is being initialized.  Calling UpdateCurrentDictionary on
+  // mPendingSpellCheck simply queues the dictionary update after the init.
+  nsCOMPtr<nsIEditorSpellCheck> spellCheck = mSpellCheck ? mSpellCheck :
+                                             mPendingSpellCheck;
+  if (!spellCheck) {
+    return NS_OK;
+  }
+
+  if (NS_FAILED(spellCheck->GetCurrentDictionary(mPreviousDictionary))) {
+    mPreviousDictionary.Truncate();
+  }
+
+  RefPtr<UpdateCurrentDictionaryCallback> cb =
+    new UpdateCurrentDictionaryCallback(this, mDisabledAsyncToken);
+  NS_ENSURE_STATE(cb);
+  nsresult rv = spellCheck->UpdateCurrentDictionary(cb);
+  if (NS_FAILED(rv)) {
+    cb = nullptr;
+    return rv;
+  }
+  mNumPendingUpdateCurrentDictionary++;
+  ChangeNumPendingSpellChecks(1);
+
+  return NS_OK;
+}
+
+// Called when nsIEditorSpellCheck::UpdateCurrentDictionary completes.
+nsresult mozInlineSpellChecker::CurrentDictionaryUpdated()
+{
+  mNumPendingUpdateCurrentDictionary--;
+  NS_ASSERTION(mNumPendingUpdateCurrentDictionary >= 0,
+               "CurrentDictionaryUpdated called without corresponding "
+               "UpdateCurrentDictionary call!");
+  ChangeNumPendingSpellChecks(-1);
+
+  nsAutoString currentDictionary;
+  if (!mSpellCheck ||
+      NS_FAILED(mSpellCheck->GetCurrentDictionary(currentDictionary))) {
+    currentDictionary.Truncate();
+  }
+
+  nsresult rv = SpellCheckRange(nullptr);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+mozInlineSpellChecker::GetSpellCheckPending(bool* aPending)
+{
+  *aPending = mNumPendingSpellChecks > 0;
+  return NS_OK;
+}