Mozilla/mozilla/extensions/spellcheck/src/mozInlineSpellChecker.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Real-time Spellchecking
 *
 * The Initial Developer of the Original Code is Mozdev Group, Inc.
 * Portions created by the Initial Developer are Copyright (C) 2004
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s): Neil Deakin (neil@mozdevgroup.com)
 *                 Scott MacGregor (mscott@mozilla.org)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsCOMPtr.h"

#include "nsString.h"
#include "nsArray.h"
#include "nsIServiceManager.h"
#include "nsIEnumerator.h"
#include "nsUnicharUtils.h"
#include "nsReadableUtils.h"

#include "mozISpellI18NManager.h"
#include "mozInlineSpellChecker.h"

#include "nsIDOMKeyEvent.h"
#include "nsIPlaintextEditor.h"
#include "nsIDOMDocument.h"
#include "nsIDOMDocumentRange.h"
#include "nsIDOMNode.h"
#include "nsIDOMNSUIEvent.h"
#include "nsIDOMElement.h"
#include "nsIDOMText.h"
#include "nsIDOMNodeList.h"
#include "nsISelection.h"
#include "nsISelectionController.h"
#include "nsITextServicesDocument.h"
#include "nsITextServicesFilter.h"
#include "nsIDOMRange.h"
#include "nsIDOMNSRange.h"
#include "nsIDOMCharacterData.h"
#include "nsIDOMDocumentTraversal.h"
#include "nsIDOMNodeFilter.h"
#include "nsIDOMEventReceiver.h"
#include "nsIContent.h"
#include "nsIContentIterator.h"
#include "nsCRT.h"
#include "cattable.h"
#include "nsIPrefService.h"
#include "nsIPrefBranch.h"

static const char kMaxSpellCheckSelectionSize[] = "extensions.spellcheck.inline.max-misspellings";

NS_INTERFACE_MAP_BEGIN(mozInlineSpellChecker)
NS_INTERFACE_MAP_ENTRY(nsIInlineSpellChecker)
NS_INTERFACE_MAP_ENTRY(nsIEditActionListener)
NS_INTERFACE_MAP_ENTRY(nsIDOMMouseListener)
NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMKeyListener)
NS_INTERFACE_MAP_ENTRY(nsIDOMKeyListener)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsIDOMEventListener, nsIDOMKeyListener)
NS_INTERFACE_MAP_END

NS_IMPL_ADDREF(mozInlineSpellChecker)
NS_IMPL_RELEASE(mozInlineSpellChecker)

mozInlineSpellChecker::SpellCheckingState
  mozInlineSpellChecker::gCanEnableSpellChecking =
  mozInlineSpellChecker::SpellCheck_Uninitialized;

mozInlineSpellChecker::mozInlineSpellChecker():mNumWordsInSpellSelection(0), mMaxNumWordsInSpellSelection(250)
{
  nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
  if (prefs)
    prefs->GetIntPref(kMaxSpellCheckSelectionSize, &mMaxNumWordsInSpellSelection); 
}

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;
}

nsresult mozInlineSpellChecker::Cleanup()
{
  return UnregisterEventListeners();
}

// 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.
//
//    This caching will prevent adding dictionaries at runtime if we start out
//    with no dictionaries! Installing dictionaries as extensions will require
//    a restart anyway, so it shouldn't be a problem.

PRBool mozInlineSpellChecker::CanEnableInlineSpellChecking() // static
{
  nsresult rv;
  if (gCanEnableSpellChecking == SpellCheck_Uninitialized) {
    gCanEnableSpellChecking = SpellCheck_NotAvailable;

    nsCOMPtr<nsIEditorSpellCheck> spellchecker =
      do_CreateInstance("@mozilla.org/editor/editorspellchecker;1", &rv);
    NS_ENSURE_SUCCESS(rv, PR_FALSE);

    PRBool canSpellCheck = PR_FALSE;
    rv = spellchecker->CanSpellCheck(&canSpellCheck);
    NS_ENSURE_SUCCESS(rv, PR_FALSE);

    if (canSpellCheck)
      gCanEnableSpellChecking = SpellCheck_Available;
  }
  return (gCanEnableSpellChecking == SpellCheck_Available);
}

// 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<nsIDOMEventReceiver> eventReceiver = do_QueryInterface(doc, &rv);
  NS_ENSURE_SUCCESS(rv, rv); 

  eventReceiver->AddEventListenerByIID(NS_STATIC_CAST(nsIDOMMouseListener*, this), NS_GET_IID(nsIDOMMouseListener));
  eventReceiver->AddEventListenerByIID(NS_STATIC_CAST(nsIDOMKeyListener*, this), NS_GET_IID(nsIDOMKeyListener));

  return NS_OK;
}

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<nsIDOMEventReceiver> eventReceiver = do_QueryInterface(doc);
  NS_ENSURE_TRUE(eventReceiver, NS_ERROR_NULL_POINTER);

  eventReceiver->RemoveEventListenerByIID(NS_STATIC_CAST(nsIDOMMouseListener*, this), NS_GET_IID(nsIDOMMouseListener));
  eventReceiver->RemoveEventListenerByIID(NS_STATIC_CAST(nsIDOMKeyListener*, this), NS_GET_IID(nsIDOMKeyListener));
  
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::GetEnableRealTimeSpell(PRBool * aEnabled)
{
  NS_ENSURE_ARG_POINTER(aEnabled);
  *aEnabled = mSpellCheck != nsnull;
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::SetEnableRealTimeSpell(PRBool aEnabled)
{
  nsresult res = NS_OK;

  if (aEnabled) {
    if (!mSpellCheck) {
      nsCOMPtr<nsIEditorSpellCheck> spellchecker = do_CreateInstance("@mozilla.org/editor/editorspellchecker;1", &res);
      if (NS_SUCCEEDED(res) && spellchecker)
      {
        nsCOMPtr<nsITextServicesFilter> filter = do_CreateInstance("@mozilla.org/editor/txtsrvfiltermail;1", &res);
        spellchecker->SetFilter(filter);
        nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
        res = spellchecker->InitSpellChecker(editor, PR_FALSE);
        NS_ENSURE_SUCCESS(res, res);

        nsCOMPtr<nsITextServicesDocument> tsDoc = do_CreateInstance("@mozilla.org/textservices/textservicesdocument;1", &res);
        NS_ENSURE_SUCCESS(res, res);

        res = tsDoc->SetFilter(filter);
        NS_ENSURE_SUCCESS(res, res);

        res = tsDoc->InitWithEditor(editor);
        NS_ENSURE_SUCCESS(res, res);

        mTextServicesDocument = tsDoc;
        mSpellCheck = spellchecker;

        // spell checking is enabled, register our event listeners to track navigation
        RegisterEventListeners();
      }
    }

    // spellcheck the current content
    res = SpellCheckRange(nsnull);
  }
  else 
  {
    nsCOMPtr<nsISelection> spellCheckSelection;
    res = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
    NS_ENSURE_SUCCESS(res, res); 
    spellCheckSelection->RemoveAllRanges();    
    mNumWordsInSpellSelection = 0;
    UnregisterEventListeners();
    mSpellCheck = nsnull;
  }

  return res;
}

NS_IMETHODIMP mozInlineSpellChecker::SpellCheckAfterEditorChange(PRInt32 action, nsISelection *aSelection,
                                                                 nsIDOMNode *previousSelectedNode, PRInt32 previousSelectedOffset,
                                                                 nsIDOMNode *aStartNode, PRInt32 aStartOffset, nsIDOMNode *aEndNode,
                                                                 PRInt32 aEndOffset)
{
  NS_ENSURE_ARG_POINTER(aSelection);
  if (!mSpellCheck)
    return NS_OK; // disabling spell checking is not an error

  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
  if (!editor) 
    return NS_ERROR_NOT_INITIALIZED;

  nsCOMPtr<nsIDOMNode> anchorNode;
  nsresult res = aSelection->GetAnchorNode(getter_AddRefs(anchorNode));
  NS_ENSURE_SUCCESS(res, res);

  PRInt32 anchorOffset;
  res = aSelection->GetAnchorOffset(&anchorOffset);
  NS_ENSURE_SUCCESS(res, res);

  nsCOMPtr<nsISelection> spellCheckSelection;
  res = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(res, res); 

  CleanupRangesInSelection(spellCheckSelection);

  switch (action)
  {
    case kOpInsertBreak:
    {
      // if we just inserted a line break, we need to finish spell checking the last word on the previous
      // line since in this case the line break is really a end of word terminator...
      res = AdjustSpellHighlighting(previousSelectedNode, previousSelectedOffset, spellCheckSelection, PR_FALSE);
      break;
    }

    case kOpMakeList:
    case kOpIndent:
    case kOpOutdent:
    case kOpAlign:
    case kOpRemoveList:
    case kOpMakeDefListItem:
      res = SpellCheckBetweenNodes(aStartNode, aStartOffset, aEndNode, aEndOffset, spellCheckSelection);
      break;

    case kOpInsertText:
    case kOpInsertIMEText:
    {
      PRInt32 offset = previousSelectedOffset;

      if (anchorNode == previousSelectedNode)
      {
        if (offset == anchorOffset) 
          offset--;
        res = AdjustSpellHighlighting(anchorNode, offset, spellCheckSelection, PR_FALSE);
      }
      else 
        res = SpellCheckBetweenNodes(aStartNode, aStartOffset, anchorNode, offset, spellCheckSelection);
      break;
    }

    case kOpHTMLPaste:
      // spell check the inserted nodes caused by the space. 
      res = SpellCheckBetweenNodes(aStartNode, aStartOffset, aEndNode, aEndOffset, spellCheckSelection);
      break;

    case kOpDeleteSelection:
    {
      // this is what happens when the delete or backspace key is pressed
      PRInt32 offset = (anchorOffset > 0) ? (anchorOffset - 1) : anchorOffset;
      res = AdjustSpellHighlighting(anchorNode, offset, spellCheckSelection, PR_TRUE);
      break;
    }

    case kOpInsertQuotation:
      // spell check the text at the previous caret position, but no need to
      // check the quoted text itself.
      res = AdjustSpellHighlighting(previousSelectedNode, previousSelectedOffset - 1,
                                    spellCheckSelection, PR_FALSE);
      break;

    case kOpRemoveTextProperty:
    case kOpResetTextProperties:
      res = SpellCheckSelection(aSelection);
      break;

    case kOpMakeBasicBlock:
      // this doesn't adjust the selection, nor add or insert any text, so
      // no words need to be spell-checked
      res = SpellCheckBetweenNodes(aStartNode,aStartOffset,aEndNode,aEndOffset, spellCheckSelection);
      break;

    case kOpLoadHTML:
    {
      // spell check the entire document
      SpellCheckRange(nsnull);
      break;
    }

    case kOpInsertElement:
      PRBool iscollapsed;
      aSelection->GetIsCollapsed(&iscollapsed);
      if (iscollapsed)
        res = AdjustSpellHighlighting(anchorNode, anchorOffset, spellCheckSelection, PR_FALSE);
      else 
        res = SpellCheckSelection(aSelection);
      break;

    case kOpSetTextProperty:
      res = SpellCheckSelection(aSelection);
      break;

    case kOpUndo:
    case kOpRedo:
      // XXX handling these cases is quite hard -- this isn't quite right
      if (anchorNode == previousSelectedNode)
        res = SpellCheckBetweenNodes(anchorNode, PR_MIN(anchorOffset, previousSelectedOffset),
                                     anchorNode, PR_MAX(anchorOffset, previousSelectedOffset), spellCheckSelection);
      else 
      {
        nsCOMPtr<nsIDOMElement> rootElem;
        res = editor->GetRootElement(getter_AddRefs(rootElem));
        NS_ENSURE_SUCCESS(res, res); 
        res = SpellCheckBetweenNodes(rootElem, 0, rootElem, -1, spellCheckSelection);
      }
      break;
  }

  // remember the current cursor position after every change..
  SaveCurrentSelectionPosition();
  return res;
}

// supply a NULL range and this will check the entire editor
NS_IMETHODIMP mozInlineSpellChecker::SpellCheckRange(nsIDOMRange *aRange)
{
  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);

  nsCOMPtr<nsISelection> spellCheckSelection;
  nsresult rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(rv, rv); 

  CleanupRangesInSelection(spellCheckSelection);

  if(aRange) {
    // use the given range
    rv = SpellCheckRange(aRange,spellCheckSelection);
  } else 
  {
    // use full range: SpellCheckBetweenNodes will do the somewhat complicated
    // task of creating a range over the element we give it and call
    // SpellCheckRange(range,selection) for us
    nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
    if (!editor)
      return NS_ERROR_NOT_INITIALIZED;
    nsCOMPtr<nsIDOMElement> rootElem;
    rv = editor->GetRootElement(getter_AddRefs(rootElem));
    NS_ENSURE_SUCCESS(rv, rv);
    rv = SpellCheckBetweenNodes(rootElem, 0, rootElem, -1, spellCheckSelection);
  }
  return rv;
}

NS_IMETHODIMP mozInlineSpellChecker::GetMispelledWord(nsIDOMNode *aNode, PRInt32 aOffset, nsIDOMRange **newword)
{
  nsCOMPtr<nsISelection> spellCheckSelection;
  nsresult res = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(res, res); 

  return IsPointInSelection(spellCheckSelection, aNode, aOffset, newword);
}

NS_IMETHODIMP mozInlineSpellChecker::ReplaceWord(nsIDOMNode *aNode, PRInt32 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 = GetMispelledWord(aNode, aOffset, getter_AddRefs(range));
  NS_ENSURE_SUCCESS(res, res); 

  if (range)
  {
    range->DeleteContents();

    nsCOMPtr<nsISelection> selection;
    res = editor->GetSelection(getter_AddRefs(selection));
    NS_ENSURE_SUCCESS(res, res); 

    nsCOMPtr<nsIDOMNode> container;
    res = range->GetStartContainer(getter_AddRefs(container));
    NS_ENSURE_SUCCESS(res, res); 

    nsCOMPtr<nsIDOMCharacterData> chars = do_QueryInterface(container);
    if (chars)
    {
      PRInt32 offset;
      res = range->GetStartOffset(&offset);
      NS_ENSURE_SUCCESS(res, res); 

      chars->InsertData(offset,newword);
      selection->Collapse(container, offset + newword.Length());
    }
    else 
    {
      nsCOMPtr<nsIDOMDocument> doc;
      res = editor->GetDocument(getter_AddRefs(doc));
      NS_ENSURE_SUCCESS(res, res); 

      nsCOMPtr<nsIDOMText> newtext;
      res = doc->CreateTextNode(newword,getter_AddRefs(newtext));
      NS_ENSURE_SUCCESS(res, res); 

      res = range->InsertNode(newtext);
      NS_ENSURE_SUCCESS(res, res); 

      selection->Collapse(newtext, newword.Length());
    }
  }

  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::AddWordToDictionary(const nsAString &word)
{
  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);

  nsAutoString wordstr(word);
  nsresult res = mSpellCheck->AddWordToDictionary(wordstr.get());
  NS_ENSURE_SUCCESS(res, res); 

  nsCOMPtr<nsISelection> spellCheckSelection;
  nsresult rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(rv, rv);

  return SpellCheckSelection(spellCheckSelection);
}

NS_IMETHODIMP mozInlineSpellChecker::IgnoreWord(const nsAString &word)
{
  NS_ENSURE_TRUE(mSpellCheck, NS_ERROR_NOT_INITIALIZED);

  nsAutoString wordstr(word);
  nsresult res = mSpellCheck->IgnoreWordAllOccurrences(wordstr.get());
  NS_ENSURE_SUCCESS(res, res); 
  
  nsCOMPtr<nsISelection> spellCheckSelection;
  nsresult rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(rv, rv);
  return SpellCheckSelection(spellCheckSelection);
}

NS_IMETHODIMP mozInlineSpellChecker::IgnoreWords(const PRUnichar **aWordsToIgnore, PRUint32 aCount)
{
  // add each word to the ignore list and then recheck the document
  for (PRUint32 index = 0; index < aCount; index++)
    mSpellCheck->IgnoreWordAllOccurrences(aWordsToIgnore[index]);

  nsCOMPtr<nsISelection> spellCheckSelection;
  nsresult rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(rv, rv);
  return SpellCheckSelection(spellCheckSelection);
}

// When the user ignores a word or adds a word to the dictionary, we used
// to re check the entire document, starting at the root element and walking through all the nodes.
// Optimization: The only words in the document that would change as a result of these actions
// are words that are already in the spell check selection (i.e. words previsouly marked as misspelled).
// Spell check the spell check selection instead of the entire document for ignore word and add word
nsresult mozInlineSpellChecker::SpellCheckSelection(nsISelection * aSelection)
{
  NS_ENSURE_ARG_POINTER(aSelection);

  nsCOMPtr<nsISelection> spellCheckSelection;
  nsresult rv = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
  NS_ENSURE_SUCCESS(rv, rv);

  // if we are going to be checking the spell check selection, then
  // clear out mNumWordsInSpellSelection since we'll be rebuilding the ranges.
  if (aSelection == spellCheckSelection.get())
    mNumWordsInSpellSelection = 0; 

  // Optimize for the case where aSelection is in fact the spell check selection.
  // 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
  PRInt32 count;
  nsCOMPtr <nsIMutableArray> ranges = do_CreateInstance(NS_ARRAY_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  aSelection->GetRangeCount(&count);
  PRInt32 index;
  for (index = 0; index < count; index++)
  {
    nsCOMPtr<nsIDOMRange> checkRange;
    aSelection->GetRangeAt(index, getter_AddRefs(checkRange));
    if (checkRange)
      ranges->AppendElement(checkRange, PR_FALSE);    
  }

  // now loop over these ranges and spell check each range
  nsCOMPtr<nsIDOMNode> startNode;
  nsCOMPtr<nsIDOMNode> endNode;
  PRInt32 startOffset, endOffset;
  nsCOMPtr<nsIDOMRange> checkRange;

  for (index = 0; index < count; index++)
  {
    checkRange = do_QueryElementAt(ranges, index); 
    if (checkRange)
    {
      checkRange->GetStartContainer(getter_AddRefs(startNode));
      checkRange->GetEndContainer(getter_AddRefs(endNode));
      checkRange->GetStartOffset(&startOffset);
      checkRange->GetEndOffset(&endOffset);

      rv |= SpellCheckBetweenNodes(startNode, startOffset, endNode, endOffset, spellCheckSelection);
    }
  }

  return rv;
}

NS_IMETHODIMP mozInlineSpellChecker::WillCreateNode(const nsAString & aTag, nsIDOMNode *aParent, PRInt32 aPosition)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::DidCreateNode(const nsAString & aTag, nsIDOMNode *aNode, nsIDOMNode *aParent,
                                                   PRInt32 aPosition, nsresult aResult)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::WillInsertNode(nsIDOMNode *aNode, nsIDOMNode *aParent,
                                                    PRInt32 aPosition)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::DidInsertNode(nsIDOMNode *aNode, nsIDOMNode *aParent,
                                                   PRInt32 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, PRInt32 aOffset)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::DidSplitNode(nsIDOMNode *aExistingRightNode, PRInt32 aOffset,
                                                  nsIDOMNode *aNewLeftNode, nsresult aResult)
{
  return SpellCheckBetweenNodes(aNewLeftNode, 0, aNewLeftNode, 0, NULL);
}

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, NULL);
}

NS_IMETHODIMP mozInlineSpellChecker::WillInsertText(nsIDOMCharacterData *aTextNode, PRInt32 aOffset, const nsAString & aString)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::DidInsertText(nsIDOMCharacterData *aTextNode, PRInt32 aOffset,
                                                   const nsAString & aString, nsresult aResult)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::WillDeleteText(nsIDOMCharacterData *aTextNode, PRInt32 aOffset, PRInt32 aLength)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::DidDeleteText(nsIDOMCharacterData *aTextNode, PRInt32 aOffset, PRInt32 aLength, nsresult aResult)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::WillDeleteSelection(nsISelection *aSelection)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::DidDeleteSelection(nsISelection *aSelection)
{
  return NS_OK;
}

nsresult
mozInlineSpellChecker::SpellCheckBetweenNodes(nsIDOMNode *aStartNode,
                                         PRInt32 aStartOffset,
                                         nsIDOMNode *aEndNode,
                                         PRInt32 aEndOffset,
                                         nsISelection *aSpellCheckSelection)
{
  nsresult res;
  nsCOMPtr<nsISelection> spellCheckSelection = aSpellCheckSelection;
  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);

  if (!spellCheckSelection)
  {
    res = GetSpellCheckSelection(getter_AddRefs(spellCheckSelection));
    NS_ENSURE_SUCCESS(res, res); 
  }

  nsCOMPtr<nsIDOMDocument> doc;
  res = editor->GetDocument(getter_AddRefs(doc));
  NS_ENSURE_SUCCESS(res, res); 

  nsCOMPtr<nsIDOMDocumentRange> docrange = do_QueryInterface(doc);
  NS_ENSURE_TRUE(docrange, NS_ERROR_FAILURE);

  nsCOMPtr<nsIDOMRange> range;
  res = docrange->CreateRange(getter_AddRefs(range));
  NS_ENSURE_SUCCESS(res, res); 

  if (aEndOffset == -1)
  {
    nsCOMPtr<nsIDOMNodeList> childNodes;
    res = aEndNode->GetChildNodes(getter_AddRefs(childNodes));
    NS_ENSURE_SUCCESS(res, res);

    PRUint32 childCount;
    res = childNodes->GetLength(&childCount);
    NS_ENSURE_SUCCESS(res, res); 

    aEndOffset = childCount;
  }

  range->SetStart(aStartNode,aStartOffset);

  if (aEndOffset) 
    range->SetEnd(aEndNode, aEndOffset);
  else 
    range->SetEndAfter(aEndNode);

  // HACK: try to avoid an assertion later on in the code when we iterate
  // over a range with only one character in it. if the range is really only one
  // character, bail out early..
  nsCOMPtr<nsIDOMNode> startNode;
  nsCOMPtr<nsIDOMNode> endNode;
  PRInt32 startOffset;
  PRInt32 endOffset; 
  range->GetStartContainer(getter_AddRefs(startNode));
  range->GetStartOffset(&startOffset);
  range->GetEndContainer(getter_AddRefs(endNode));
  range->GetEndOffset(&endOffset);

  if (startNode == endNode && startOffset == endOffset)
    return NS_OK; // don't call adjust spell highlighting for a single character

  return SpellCheckRange(range,spellCheckSelection);
}

static inline PRBool IsNonwordChar(PRUnichar chr)
{
  // a non-word character is one that can end a word, such as whitespace or
  // most punctuation. 
  // mscott: We probably need to modify this to make it work for non ascii 
  // based languages...  but then again our spell checker doesn't support 
  // multi byte languages anyway.
  // jshin: one way to make the word boundary checker more generic is to
  // use 'word breaker(s)' in intl.
  // Need to fix callers (of IsNonwordChar) to pass PRUint32
  return ((chr != '\'') && (GetCat(PRUint32(chr)) != 5));
}

// 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.
nsresult mozInlineSpellChecker::SkipSpellCheckForNode(nsIDOMNode *aNode, PRBool *checkSpelling)
{
  *checkSpelling = PR_TRUE;
  NS_ENSURE_ARG_POINTER(aNode);

  nsCOMPtr<nsIEditor> editor (do_QueryReferent(mEditor));
  NS_ENSURE_TRUE(editor, NS_ERROR_NULL_POINTER);

  PRUint32 flags;
  editor->GetFlags(&flags);
  if (flags & nsIPlaintextEditor::eEditorMailMask)
  {
    nsCOMPtr<nsIDOMNode> parent;
    aNode->GetParentNode(getter_AddRefs(parent));

    while (parent)
    {
      nsCOMPtr<nsIDOMElement> parentElement = do_QueryInterface(parent);
      if (!parentElement)
        break;

      nsAutoString parentTagName;
      parentElement->GetTagName(parentTagName);

      if (parentTagName.Equals(NS_LITERAL_STRING("blockquote"), nsCaseInsensitiveStringComparator()))
      {
        *checkSpelling = PR_FALSE;
        break;
      }
      else if (parentTagName.Equals(NS_LITERAL_STRING("pre"), nsCaseInsensitiveStringComparator()))
      {
        nsAutoString classname;
        parentElement->GetAttribute(NS_LITERAL_STRING("class"),classname);
        if (classname.Equals(NS_LITERAL_STRING("moz-signature")))
          *checkSpelling = PR_FALSE;
      }

      nsCOMPtr<nsIDOMNode> nextParent;
      parent->GetParentNode(getter_AddRefs(nextParent));
      parent = nextParent;
    }
  }

  return NS_OK;
}

nsresult mozInlineSpellChecker::EnsureConverter()
{
  nsresult res = NS_OK;
  if (!mConverter)
  {
    nsCOMPtr<mozISpellI18NManager> manager(do_GetService("@mozilla.org/spellchecker/i18nmanager;1", &res));
    if (manager && NS_SUCCEEDED(res))
    {
      nsXPIDLString language;
      res = manager->GetUtil(language.get(), getter_AddRefs(mConverter));
    }
  }
  return res;
}

// takes a point in a text node and generates a range for the word containing that point. Note: 
// aWordRange will be NULL if we don't have a word.
nsresult mozInlineSpellChecker::GenerateRangeForSurroundingWord(nsIDOMNode * aNode, PRInt32 aOffset, nsIDOMRange ** aWordRange)
{
  NS_ENSURE_ARG_POINTER(aNode);

  PRUint32 textLength = 0;
  const PRUnichar *textChars = nsnull;
  nsAutoString text;
  nsresult rv = aNode->GetNodeValue(text);
  NS_ENSURE_SUCCESS(rv, rv); 

  rv = EnsureConverter();
  NS_ENSURE_SUCCESS(rv, rv);

  textChars = text.get();
  textLength = text.Length();
  if (aOffset == -1 || aOffset >= textLength) 
    aOffset = textLength - 1;
  if (aOffset < 0)
    aOffset = 0;

  PRInt32 currentOffset = aOffset;
  if (currentOffset && textChars[currentOffset] == ' ')
    currentOffset--;

  // back up our offset into the text node until we hit the beginning of the text OR
  // we find white space (NOT punctuation)
  while (currentOffset && textChars[currentOffset] != ' ')
    currentOffset--;

  PRInt32 lastWordBeginPosition = -1;
  PRInt32 lastWordEndPos = -1;
  PRInt32 begin;
  PRInt32 end;

  do 
  {
    rv = mConverter->FindNextWord(textChars, textLength, currentOffset, &begin, &end);
    if (NS_SUCCEEDED(rv) && (begin != -1))
    {
      lastWordBeginPosition = begin;
      lastWordEndPos = end;
      currentOffset = lastWordEndPos;
    }
  } while (begin != -1 && currentOffset < aOffset);

  // only return the range if our original point in the string is inside the word
  if (aOffset >= lastWordBeginPosition && aOffset <= lastWordEndPos) 
  {
    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); 

    nsCOMPtr<nsIDOMDocumentRange> docrange = do_QueryInterface(doc);
    nsCOMPtr<nsIDOMRange> range; 
    rv = docrange->CreateRange(aWordRange);
    NS_ENSURE_SUCCESS(rv, rv); 

    (*aWordRange)->SetStart(aNode, lastWordBeginPosition);
    (*aWordRange)->SetEnd(aNode, lastWordEndPos);
  }
  else
    *aWordRange = nsnull;

  return NS_OK;
}

nsresult
mozInlineSpellChecker::AdjustSpellHighlighting(nsIDOMNode *aNode,
                                               PRInt32 aOffset,
                                               nsISelection *aSpellCheckSelection,
                                               PRBool isDeletion)
{  
  NS_ENSURE_TRUE(aNode, NS_OK); 
  nsCOMPtr<nsIDOMNode> currentNode = aNode;
  nsresult rv = NS_OK; 
  do 
  {
    PRUint16 nodeType;
    rv = currentNode->GetNodeType(&nodeType);
    NS_ENSURE_SUCCESS(rv, rv); 

    if (nodeType == nsIDOMNode::TEXT_NODE) 
      break;

    nsCOMPtr<nsIDOMNodeList> childNodes;
    rv = currentNode->GetChildNodes(getter_AddRefs(childNodes));
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIDOMNode> child;
    rv = childNodes->Item(aOffset, getter_AddRefs(child));
    NS_ENSURE_SUCCESS(rv, rv); 

    currentNode = child;
    aOffset = 0;
  } while (currentNode);

  // make sure we found a text node
  if (!currentNode) 
    return NS_OK; 

  // HACK: special case deletion when we had to walk up the dom tree to find the previous text node.
  // Reset the offset to be the end of this previous text node instead of the beginning
  if (isDeletion && currentNode != aNode)
  {
    nsAutoString text;
    rv = currentNode->GetNodeValue(text);
    if (text.Length())
      aOffset = text.Length() - 1;
  }

  nsCOMPtr<nsIDOMRange> wordRange;
  rv = GenerateRangeForSurroundingWord(currentNode, aOffset, getter_AddRefs(wordRange));

  // if we don't have a word range to examine, then bail out early.
  if (!wordRange || aOffset < 0)
    return NS_OK;

  // if the user just started typing inside of an existing word, remove that word from the spell check
  // selection list (if it was even there)
  if (!EndOfAWord(currentNode, aOffset) && !isDeletion)
    RemoveCurrentWordFromSpellSelection(aSpellCheckSelection, wordRange);

  // if we aren't at the end of a word then don't kick off inline spell checking
  // if we are processing a delete character, proceed so we can clear the spell check underline of the
  // current word.
  // Extra logic: if we are handling a deletion and the current character (after the delete) is a end of word
  // delimter (like a space) then don't clear the underline selection of the word. This fixes the case where
  // you type: "helllo  world". Put the cursor to the left of 'w' and hit back space, as long as there is white
  // space between the cursor and the last character in the previous word (helllo) we shouldn't clear the highlight
  // selection on helllo. 
  if ((!EndOfAWord(currentNode, aOffset) && !isDeletion) || (isDeletion && EndOfAWord(currentNode, aOffset)))
    return NS_OK;

  PRBool checkSpelling;
  SkipSpellCheckForNode(currentNode, &checkSpelling); 
  if (!checkSpelling) 
    return NS_OK;

  rv = RemoveCurrentWordFromSpellSelection(aSpellCheckSelection, wordRange);

  // for the case of deletion, if the cursor is inside of a spell check selection (i.e.
  // the user typed some text then a word terminator and hit backspace to fix the spelling)
  // we should clear the red underline from that word since they are now editing it again. 
  if (isDeletion)
    return NS_OK;

  // expand the current selection point to a word range
  PRBool isMisspelled = PR_FALSE;
  nsAutoString word;
  wordRange->ToString(word);

  // empty words should be skipped
  if (word.IsEmpty())
    return NS_OK;

  rv = mSpellCheck->CheckCurrentWordNoSuggest(word.get(),&isMisspelled);
  NS_ENSURE_SUCCESS(rv, rv); 

  if (isMisspelled) 
    AddRange(aSpellCheckSelection, wordRange);

  return NS_OK;
}

// SpellCheckRange --> Looks for words that span aRange and spell checks each individual word. 
nsresult mozInlineSpellChecker::SpellCheckRange(nsIDOMRange *aRange, nsISelection *aSpellCheckSelection)
{
  nsCOMPtr<nsIDOMRange> selectionRange;
  nsresult res = aRange->CloneRange(getter_AddRefs(selectionRange));
  NS_ENSURE_SUCCESS(res, res); 

  PRBool iscollapsed;
  res = aRange->GetCollapsed(&iscollapsed);
  NS_ENSURE_SUCCESS(res, res);

  res = mTextServicesDocument->SetExtent(selectionRange);
  NS_ENSURE_SUCCESS(res, res); 

  res = EnsureConverter();
  NS_ENSURE_SUCCESS(res, res);

  PRBool done, isMisspelled;
  PRInt32 begin, end, startOffset, endOffset;
  PRUint32 selOffset = 0;
  nsCOMPtr<nsIDOMNode> startNode;
  nsCOMPtr<nsIDOMNode> endNode;

  while (!SpellCheckSelectionIsFull() && NS_SUCCEEDED(mTextServicesDocument->IsDone(&done)) && !done)
  {
    nsAutoString textblock;
    res = mTextServicesDocument->GetCurrentTextBlock(&textblock);
    NS_ENSURE_SUCCESS(res, res); 

    do 
    {
      const PRUnichar *textChars = textblock.get();
      PRInt32 textLength = textblock.Length();

      res = mConverter->FindNextWord(textChars, textLength, selOffset, &begin, &end);
      if (NS_SUCCEEDED(res) && (begin != -1))
      {
        const nsAString &word = Substring(textblock, begin, end - begin);
        res = mSpellCheck->CheckCurrentWordNoSuggest(PromiseFlatString(word).get(), &isMisspelled);

        nsCOMPtr<nsIDOMRange> wordrange;
        res = mTextServicesDocument->GetDOMRangeFor(begin, end - begin, getter_AddRefs(wordrange));

        wordrange->GetStartContainer(getter_AddRefs(startNode));
        wordrange->GetEndContainer(getter_AddRefs(endNode));
        wordrange->GetStartOffset(&startOffset);
        wordrange->GetEndOffset(&endOffset);

        PRBool checkSpelling;
        SkipSpellCheckForNode(startNode, &checkSpelling);
        if (!checkSpelling) 
          break;

        nsCOMPtr<nsIDOMRange> currentRange;
        IsPointInSelection(aSpellCheckSelection, startNode, startOffset,
                           getter_AddRefs(currentRange));
        if (!currentRange)
          IsPointInSelection(aSpellCheckSelection, endNode, endOffset - 1, getter_AddRefs(currentRange));

        if (currentRange) // remove the old range first
          RemoveRange(aSpellCheckSelection, currentRange);
        if (isMisspelled)
          AddRange(aSpellCheckSelection, wordrange);
      }
      selOffset = end;
    } while (end != -1 && !SpellCheckSelectionIsFull());

    mTextServicesDocument->NextBlock();
    selOffset = 0;
  }

  return NS_OK;
}

PRBool mozInlineSpellChecker::EndOfAWord(nsIDOMNode *aNode, PRInt32 aOffset)
{
  PRBool endOfWord = PR_FALSE;
  nsAutoString text;
  PRUint16 nodeType;

  if (aNode)
  {
    nsresult res = aNode->GetNodeType(&nodeType);
    if (NS_SUCCEEDED(res)) 
    {
      if (nodeType == nsIDOMNode::TEXT_NODE) {
        res = aNode->GetNodeValue(text);
      if (NS_SUCCEEDED(res) && IsNonwordChar(text[aOffset]))
        endOfWord = PR_TRUE;
      }
    }
  }

  return endOfWord;
}

nsresult
mozInlineSpellChecker::IsPointInSelection(nsISelection *aSelection,
                                     nsIDOMNode *aNode,
                                     PRInt32 aOffset,
                                     nsIDOMRange **aRange)
{
  *aRange = NULL;
  NS_ENSURE_ARG_POINTER(aNode);
  NS_ENSURE_ARG_POINTER(aSelection);

  PRInt32 count;
  aSelection->GetRangeCount(&count);

  PRInt32 t;
  for (t=0; t<count; t++)
  {
    nsCOMPtr<nsIDOMRange> checkRange;
    aSelection->GetRangeAt(t,getter_AddRefs(checkRange));
    nsCOMPtr<nsIDOMNSRange> nsCheckRange = do_QueryInterface(checkRange);

    PRInt32 start, end;
    checkRange->GetStartOffset(&start);
    checkRange->GetEndOffset(&end);

    PRBool isInRange;
    nsCheckRange->IsPointInRange(aNode,aOffset,&isInRange);
    if (isInRange)
    {
      *aRange = checkRange;
      NS_ADDREF(*aRange);
      break;
    }
  }

  return NS_OK;
}

nsresult
mozInlineSpellChecker::CleanupRangesInSelection(nsISelection *aSelection)
{
  // integrity check - remove ranges that have collapsed to nothing. This
  // can happen if the node containing a highlighted word was removed.
  NS_ENSURE_ARG_POINTER(aSelection);

  PRInt32 count;
  aSelection->GetRangeCount(&count);

  for (PRInt32 index = 0; index < count; index++)
  {
    nsCOMPtr<nsIDOMRange> checkRange;
    aSelection->GetRangeAt(index, getter_AddRefs(checkRange));

    if (checkRange)
    {
      PRBool collapsed;
      checkRange->GetCollapsed(&collapsed);
      if (collapsed)
      {
        RemoveRange(aSelection, checkRange);
        index--;
        count--;
      }
    }
  }

  return NS_OK;
}

// 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(nsISelection *aSpellCheckSelection, nsIDOMRange * aRange)
{
  NS_ENSURE_ARG_POINTER(aSpellCheckSelection);
  NS_ENSURE_ARG_POINTER(aRange);

  nsresult rv = aSpellCheckSelection->RemoveRange(aRange);
  if (NS_SUCCEEDED(rv) && mNumWordsInSpellSelection)
    mNumWordsInSpellSelection--;

  return rv;
}

// 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;
}

// a helper routine that expands the current position in the selection to the surrounding word
// and then removes it from the spell checker selection
nsresult mozInlineSpellChecker::RemoveCurrentWordFromSpellSelection(nsISelection *aSpellCheckSelection, nsIDOMRange * aWordRange)
{
  NS_ENSURE_ARG_POINTER(aSpellCheckSelection);
  NS_ENSURE_ARG_POINTER(aWordRange);

  nsCOMPtr<nsIDOMNode> startNode;
  nsCOMPtr<nsIDOMNode> endNode;
  PRInt32 startOffset, endOffset;

  aWordRange->GetStartContainer(getter_AddRefs(startNode));
  aWordRange->GetEndContainer(getter_AddRefs(endNode));
  aWordRange->GetStartOffset(&startOffset);
  aWordRange->GetEndOffset(&endOffset);
  
  nsCOMPtr<nsIDOMRange> currentRange;
  
  IsPointInSelection(aSpellCheckSelection, startNode, startOffset, getter_AddRefs(currentRange));
  if (currentRange)
    RemoveRange(aSpellCheckSelection, currentRange);
  
  IsPointInSelection(aSpellCheckSelection, endNode, endOffset - 1, getter_AddRefs(currentRange));
  if (currentRange) 
    RemoveRange(aSpellCheckSelection, currentRange);

  return NS_OK;
}

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); 

  nsCOMPtr<nsISelection> spellCheckSelection;
  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 cursor 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;
}

// HandleNavigationEvent: acts upon mouse clicks and keyboard navigation changes,
// spell checking the previous word if the new navigation location movees 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 trys to work around this for the DOM_VK_RIGHT and DOM_VK_LEFT cases.
nsresult mozInlineSpellChecker::HandleNavigationEvent(nsIDOMEvent * aEvent, PRBool aForceWordSpellCheck, PRInt32 aNewPositionOffset)
{
  // get the current selection and compare it to the new selection.
  nsresult rv;
  
  nsCOMPtr<nsIDOMNode> currentAnchorNode = mCurrentSelectionAnchorNode;
  PRInt32 currentAnchorOffset = mCurrentSelectionOffset;

  // now remember the new focus position resulting from the event
  SaveCurrentSelectionPosition(); 

  NS_ENSURE_TRUE(currentAnchorNode, NS_OK);

  // expand the old selection into a range for the nearest word boundary
  nsCOMPtr<nsIDOMRange> currentWordRange; 
  GenerateRangeForSurroundingWord(currentAnchorNode, currentAnchorOffset, getter_AddRefs(currentWordRange));

  if (!currentWordRange) 
    return NS_OK;

  nsAutoString word;
  currentWordRange->ToString(word);

  nsCOMPtr<nsIDOMNSRange> currentWordNSRange = do_QueryInterface(currentWordRange, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  PRBool isInRange;
  rv = currentWordNSRange->IsPointInRange(mCurrentSelectionAnchorNode, mCurrentSelectionOffset + aNewPositionOffset, &isInRange);
  NS_ENSURE_SUCCESS(rv, rv);
  
  if (!isInRange || aForceWordSpellCheck) // selection is moving to a new word, spell check the current word
  {
    nsCOMPtr<nsISelection> spellCheckSelection; 
    GetSpellCheckSelection(getter_AddRefs(spellCheckSelection)); 
    SpellCheckRange(currentWordRange, spellCheckSelection);
  }
  
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::HandleEvent(nsIDOMEvent* aEvent)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::MouseClick(nsIDOMEvent *aMouseEvent)
{
  // ignore any errors from HandleNavigationEvent as we don't want to prevent 
  // anyone else from seeing this event. 
  HandleNavigationEvent(aMouseEvent, PR_FALSE);
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::MouseDown(nsIDOMEvent* aMouseEvent)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::MouseUp(nsIDOMEvent* aMouseEvent)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::MouseDblClick(nsIDOMEvent* aMouseEvent)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::MouseOver(nsIDOMEvent* aMouseEvent)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::MouseOut(nsIDOMEvent* aMouseEvent)
{
  return NS_OK;
}

NS_IMETHODIMP mozInlineSpellChecker::KeyDown(nsIDOMEvent* aKeyEvent)
{
  return NS_OK;
}


NS_IMETHODIMP mozInlineSpellChecker::KeyUp(nsIDOMEvent* aKeyEvent)
{
  return NS_OK;
}


NS_IMETHODIMP mozInlineSpellChecker::KeyPress(nsIDOMEvent* aKeyEvent)
{
  nsCOMPtr<nsIDOMKeyEvent>keyEvent = do_QueryInterface(aKeyEvent);
  NS_ENSURE_TRUE(keyEvent, NS_OK);

  PRUint32 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(aKeyEvent, PR_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(aKeyEvent, PR_TRUE /* force a spelling correction */);
      break;
  }

  return NS_OK;
}