pjs/editor/base/nsEditor.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape 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/NPL/
 *
 * 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 mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#ifndef __editor_h__
#define __editor_h__

#include "nsCOMPtr.h"
#include "nsWeakPtr.h"

#include "nsIEditor.h"
#include "nsIEditorIMESupport.h"

#include "nsIDOMDocument.h"
#include "nsIDiskDocument.h"
#include "nsIDOMSelection.h"
#include "nsIDOMCharacterData.h"
#include "nsIDOMEventListener.h"
#include "nsIDOMRange.h"
#include "nsIPrivateTextRange.h"
#include "nsITransactionManager.h"
#include "TransactionFactory.h"
#include "nsIComponentManager.h"
#include "nsISupportsArray.h"
#include "nsIEditProperty.h"
#include "nsIFileSpec.h"
#include "nsIDOMCharacterData.h"
#include "nsICSSStyleSheet.h"
#include "nsIDTD.h"
#include "nsIDOMElement.h"
#include "nsVoidArray.h"

class nsIEditActionListener;
class nsIDocumentStateListener;
class nsIDOMCharacterData;
class nsIDOMRange;
class nsIPresShell;
class nsIViewManager;
class ChangeAttributeTxn;
class CreateElementTxn;
class InsertElementTxn;
class DeleteElementTxn;
class InsertTextTxn;
class DeleteTextTxn;
class SplitElementTxn;
class JoinElementTxn;
class EditAggregateTxn;
class nsVoidArray;
class nsISupportsArray;
class nsILocale;
class IMETextTxn;
class AddStyleSheetTxn;
class RemoveStyleSheetTxn;
class nsFileSpec;

/***************************************************************************
 * class for recording selection info.  stores selection as collection of
 * { {startnode, startoffset} , {endnode, endoffset} } tuples.  Cant store
 * ranges since dom gravity will possibly change the ranges.
 */

// first a helper struct for saving/setting ranges
struct SelRangeStore 
{
  nsresult StoreRange(nsIDOMRange *aRange);
  nsresult GetRange(nsCOMPtr<nsIDOMRange> *outRange);
        
  nsCOMPtr<nsIDOMNode> startNode;
  PRInt32              startOffset;
  nsCOMPtr<nsIDOMNode> endNode;
  PRInt32              endOffset;
};

class nsSelectionState
{
  public:
      
    nsSelectionState();
    ~nsSelectionState();
  
    nsresult SaveSelection(nsIDOMSelection *aSel);
    nsresult RestoreSelection(nsIDOMSelection *aSel);
    PRBool   IsCollapsed();
    PRBool   IsEqual(nsSelectionState *aSelState);

    nsVoidArray mArray;
};

/** implementation of an editor object.  it will be the controler/focal point 
 *  for the main editor services. i.e. the GUIManager, publishing, transaction 
 *  manager, event interfaces. the idea for the event interfaces is to have them 
 *  delegate the actual commands to the editor independent of the XPFE implementation.
 */
class nsEditor : public nsIEditor,
                 public nsIEditorIMESupport
{
public:

  enum IterDirection
  {
    kIterForward,
    kIterBackward
  };

  enum OperationID
  {
    kOpIgnore = -1,
    kOpNone = 0,
    kOpUndo,
    kOpRedo,
    kOpSetTextProperty,
    kOpRemoveTextProperty,
    kOpInsertNode,
    kOpCreateNode,
    kOpDeleteNode,
    kOpSplitNode,
    kOpJoinNode,
    kOpDeleteText,
    kOpInsertText,
    kOpInsertIMEText,
    kOpDeleteSelection
  };

  static const char* kMOZEditorBogusNodeAttr;
  static const char* kMOZEditorBogusNodeValue;

  /** The default constructor. This should suffice. the setting of the interfaces is done
   *  after the construction of the editor class.
   */
  nsEditor();
  /** The default destructor. This should suffice. Should this be pure virtual 
   *  for someone to derive from the nsEditor later? I dont believe so.
   */
  virtual ~nsEditor();
  
//Interfaces for addref and release and queryinterface
//NOTE: Use   NS_DECL_ISUPPORTS_INHERITED in any class inherited from nsEditor
  NS_DECL_ISUPPORTS

  /* ------------ nsIEditor methods -------------- */
  NS_IMETHOD Init(nsIDOMDocument *aDoc, nsIPresShell *aPresShell, PRUint32 aFlags);
  NS_IMETHOD PostCreate();
  NS_IMETHOD GetFlags(PRUint32 *aFlags) = 0;
  NS_IMETHOD SetFlags(PRUint32 aFlags) = 0;
  NS_IMETHOD GetDocument(nsIDOMDocument **aDoc);
  NS_IMETHOD GetPresShell(nsIPresShell **aPS);
  NS_IMETHOD GetSelection(nsIDOMSelection **aSelection);
  
  NS_IMETHOD EnableUndo(PRBool aEnable);
  NS_IMETHOD Do(nsITransaction *aTxn);
  NS_IMETHOD Undo(PRUint32 aCount);
  NS_IMETHOD CanUndo(PRBool &aIsEnabled, PRBool &aCanUndo);
  NS_IMETHOD Redo(PRUint32 aCount);
  NS_IMETHOD CanRedo(PRBool &aIsEnabled, PRBool &aCanRedo);

  NS_IMETHOD BeginTransaction();
  NS_IMETHOD EndTransaction();

  NS_IMETHOD BeginPlaceHolderTransaction(nsIAtom *aName);
  NS_IMETHOD EndPlaceHolderTransaction();
  NS_IMETHOD ShouldTxnSetSelection(PRBool *aResult);

  // pure virtual, because the definition of 'empty' depends on the doc type
  NS_IMETHOD GetDocumentIsEmpty(PRBool *aDocumentIsEmpty)=0;

  // file handling
  NS_IMETHOD GetDocumentModified(PRBool *outDocModified);
  NS_IMETHOD GetDocumentCharacterSet(PRUnichar** characterSet);
  NS_IMETHOD SetDocumentCharacterSet(const PRUnichar* characterSet);
  NS_IMETHOD SaveFile(nsFileSpec *aFileSpec, PRBool aReplaceExisting, PRBool aSaveCopy, nsIDiskDocument::ESaveFileType aSaveFileType);

  // these are pure virtual in this base class
  NS_IMETHOD Cut() = 0;
  NS_IMETHOD CanCut(PRBool &aCanCut)=0;
  NS_IMETHOD Copy() = 0;
  NS_IMETHOD CanCopy(PRBool &aCanCopy)=0;
  NS_IMETHOD Paste() = 0;
  NS_IMETHOD CanPaste(PRBool &aCanPaste)=0;

  NS_IMETHOD SelectAll();

  NS_IMETHOD BeginningOfDocument();
  NS_IMETHOD EndOfDocument();


  /* Node and element manipulation */
  NS_IMETHOD SetAttribute(nsIDOMElement * aElement, 
                          const nsString& aAttribute, 
                          const nsString& aValue);
                          
  NS_IMETHOD GetAttributeValue(nsIDOMElement * aElement, 
                               const nsString& aAttribute, 
                               nsString&       aResultValue, 
                               PRBool&         aResultIsSet);
                               
  NS_IMETHOD RemoveAttribute(nsIDOMElement *aElement, const nsString& aAttribute);

  NS_IMETHOD CreateNode(const nsString& aTag,
                        nsIDOMNode *    aParent,
                        PRInt32         aPosition,
                        nsIDOMNode **   aNewNode);
                        
  NS_IMETHOD InsertNode(nsIDOMNode * aNode,
                        nsIDOMNode * aParent,
                        PRInt32      aPosition);

  NS_IMETHOD SplitNode(nsIDOMNode * aExistingRightNode,
                       PRInt32      aOffset,
                       nsIDOMNode ** aNewLeftNode);

  NS_IMETHOD JoinNodes(nsIDOMNode * aLeftNode,
                       nsIDOMNode * aRightNode,
                       nsIDOMNode * aParent);

  NS_IMETHOD DeleteNode(nsIDOMNode * aChild);

  /* formatting within the dom tree */
  NS_IMETHOD InsertNoneditableTextNode(nsIDOMNode* aParent,
                                       PRInt32 aOffset,
                                       nsString& aStr);
  NS_IMETHOD InsertFormattingForNode(nsIDOMNode* aNode);


  /* output */
  NS_IMETHOD OutputToString(nsString& aOutputString,
                            const nsString& aFormatType,
                            PRUint32 aFlags);
                            
  NS_IMETHOD OutputToStream(nsIOutputStream* aOutputStream,
                            const nsString& aFormatType,
                            const nsString* aCharsetOverride,
                            PRUint32 aFlags);

  /* Listeners */
  NS_IMETHOD AddEditActionListener(nsIEditActionListener *aListener);
  NS_IMETHOD RemoveEditActionListener(nsIEditActionListener *aListener);

  NS_IMETHOD AddDocumentStateListener(nsIDocumentStateListener *aListener);
  NS_IMETHOD RemoveDocumentStateListener(nsIDocumentStateListener *aListener);


  NS_IMETHOD DumpContentTree();
  NS_IMETHOD DebugDumpContent() const;
  NS_IMETHOD DebugUnitTests(PRInt32 *outNumTests, PRInt32 *outNumTestsFailed);

  /* ------------ nsIEditorIMESupport methods -------------- */
  
  NS_IMETHOD BeginComposition(nsTextEventReply* aReply);
  NS_IMETHOD QueryComposition(nsTextEventReply* aReply);
  NS_IMETHOD SetCompositionString(const nsString& aCompositionString, nsIPrivateTextRangeList* aTextRangeList,nsTextEventReply* aReply);
  NS_IMETHOD EndComposition(void);
  NS_IMETHOD ForceCompositionEnd(void);

public:

  
  NS_IMETHOD InsertTextImpl(const nsString& aStringToInsert);
  NS_IMETHOD DeleteSelectionImpl(EDirection aAction);


protected:



  //NOTE: Most callers are dealing with Nodes,
  //  but these objects must supports nsIDOMElement
  NS_IMETHOD CloneAttributes(nsIDOMNode *aDestNode, nsIDOMNode *aSourceNode);
  /*
  NS_IMETHOD SetProperties(nsVoidArray *aPropList);
  NS_IMETHOD GetProperties(nsVoidArray *aPropList);
  */
  
  /** create a transaction for setting aAttribute to aValue on aElement
    */
  NS_IMETHOD CreateTxnForSetAttribute(nsIDOMElement *aElement, 
                                      const nsString& aAttribute, 
                                      const nsString& aValue,
                                      ChangeAttributeTxn ** aTxn);

  /** create a transaction for removing aAttribute on aElement
    */
  NS_IMETHOD CreateTxnForRemoveAttribute(nsIDOMElement *aElement, 
                                         const nsString& aAttribute,
                                         ChangeAttributeTxn ** aTxn);

  /** create a transaction for creating a new child node of aParent of type aTag.
    */
  NS_IMETHOD CreateTxnForCreateElement(const nsString& aTag,
                                       nsIDOMNode     *aParent,
                                       PRInt32         aPosition,
                                       CreateElementTxn ** aTxn);

  /** create a transaction for inserting aNode as a child of aParent.
    */
  NS_IMETHOD CreateTxnForInsertElement(nsIDOMNode * aNode,
                                       nsIDOMNode * aParent,
                                       PRInt32      aOffset,
                                       InsertElementTxn ** aTxn);

  /** create a transaction for removing aElement from its parent.
    */
  NS_IMETHOD CreateTxnForDeleteElement(nsIDOMNode * aElement,
                                       DeleteElementTxn ** aTxn);


  NS_IMETHOD CreateTxnForDeleteSelection(EDirection aAction,
                                              EditAggregateTxn  ** aTxn);

  NS_IMETHOD CreateTxnForDeleteInsertionPoint(nsIDOMRange         *aRange, 
                                              EDirection aAction, 
                                              EditAggregateTxn    *aTxn);


  /** create a transaction for inserting aStringToInsert into aTextNode
    * if aTextNode is null, the string is inserted at the current selection.
    */
  NS_IMETHOD CreateTxnForInsertText(const nsString & aStringToInsert,
                                    nsIDOMCharacterData *aTextNode,
                                    PRInt32 aOffset,
                                    InsertTextTxn ** aTxn);

  NS_IMETHOD CreateTxnForIMEText(const nsString & aStringToInsert,
                                 IMETextTxn ** aTxn);

  /** create a transaction for adding a style sheet
    */
  NS_IMETHOD CreateTxnForAddStyleSheet(nsICSSStyleSheet* aSheet, AddStyleSheetTxn* *aTxn);

  /** create a transaction for removing a style sheet
    */
  NS_IMETHOD CreateTxnForRemoveStyleSheet(nsICSSStyleSheet* aSheet, RemoveStyleSheetTxn* *aTxn);
  
  NS_IMETHOD PrepareToInsertText(nsCOMPtr<nsIDOMCharacterData> *aOutTextNode, PRInt32 *aOutOffset);

  NS_IMETHOD DeleteText(nsIDOMCharacterData *aElement,
                        PRUint32             aOffset,
                        PRUint32             aLength);

  NS_IMETHOD CreateTxnForDeleteText(nsIDOMCharacterData *aElement,
                                    PRUint32             aOffset,
                                    PRUint32             aLength,
                                    DeleteTextTxn      **aTxn);
	
  NS_IMETHOD CreateTxnForSplitNode(nsIDOMNode *aNode,
                                   PRUint32    aOffset,
                                   SplitElementTxn **aTxn);

  NS_IMETHOD CreateTxnForJoinNode(nsIDOMNode  *aLeftNode,
                                  nsIDOMNode  *aRightNode,
                                  JoinElementTxn **aTxn);


  // called each time we modify the document. Increments the mod
  // count of the doc.
  NS_IMETHOD IncDocModCount(PRInt32 inNumMods);
  
  // return the mod count of the doc we are editing. Zero means unchanged.
  NS_IMETHOD GetDocModCount(PRInt32 &outModCount);
  
  // called ONLY when we need to override the doc's modification
  // state. This should already be handled by nsIDiskDocument.
  NS_IMETHOD ResetDocModCount();
  
  // called after a transaction is done successfully
  NS_IMETHOD DoAfterDoTransaction(nsITransaction *aTxn);
  // called after a transaction is undone successfully
  NS_IMETHOD DoAfterUndoTransaction();
  // called after a transaction is redone successfully
  NS_IMETHOD DoAfterRedoTransaction();
  
  // called after the document has been saved
  NS_IMETHOD DoAfterDocumentSave();
  
  
  typedef enum {
    eDocumentCreated,
    eDocumentToBeDestroyed,
    eDocumentStateChanged
  } TDocumentListenerNotification;
  
  // tell the doc state listeners that the doc state has changed
  NS_IMETHOD NotifyDocumentListeners(TDocumentListenerNotification aNotificationType);
  
  /** make the given selection span the entire document */
  NS_IMETHOD SelectEntireDocument(nsIDOMSelection *aSelection);
  
protected:
// XXXX: Horrible hack! We are doing this because
// of an error in Gecko which is not rendering the
// document after a change via the DOM - gpk 2/13/99
  void HACKForceRedraw(void);

  NS_IMETHOD ScrollIntoView(PRBool aScrollToBegin);

public:

  /** return the body element */
  /** It would make more sense for this to be in nsHTMLEditor, no? */
  NS_IMETHOD GetBodyElement(nsIDOMElement **aElement);

  /** All editor operations which alter the doc should be prefaced
   *  with a call to StartOperation, naming the action and direction */
  NS_IMETHOD StartOperation(PRInt32 opID, nsIEditor::EDirection aDirection);

  /** All editor operations which alter the doc should be followed
   *  with a call to EndOperation, naming the action and direction */
  NS_IMETHOD EndOperation(PRInt32 opID, nsIEditor::EDirection aDirection, PRBool aSetSelection);

  /** return the string that represents text nodes in the content tree */
  static nsresult GetTextNodeTag(nsString& aOutString);

  /** 
   * SplitNode() creates a new node identical to an existing node, and split the contents between the two nodes
   * @param aExistingRightNode   the node to split.  It will become the new node's next sibling.
   * @param aOffset              the offset of aExistingRightNode's content|children to do the split at
   * @param aNewLeftNode         [OUT] the new node resulting from the split, becomes aExistingRightNode's previous sibling.
   * @param aParent              the parent of aExistingRightNode
   */
  nsresult SplitNodeImpl(nsIDOMNode *aExistingRightNode,
                         PRInt32     aOffset,
                         nsIDOMNode *aNewLeftNode,
                         nsIDOMNode *aParent);

  /** 
   * JoinNodes() takes 2 nodes and merge their content|children.
   * @param aNodeToKeep   The node that will remain after the join.
   * @param aNodeToJoin   The node that will be joined with aNodeToKeep.
   *                      There is no requirement that the two nodes be of the same type.
   * @param aParent       The parent of aNodeToKeep
   * @param aNodeToKeepIsFirst  if PR_TRUE, the contents|children of aNodeToKeep come before the
   *                            contents|children of aNodeToJoin, otherwise their positions are switched.
   */
  nsresult JoinNodesImpl(nsIDOMNode *aNodeToKeep,
                         nsIDOMNode *aNodeToJoin,
                         nsIDOMNode *aParent,
                         PRBool      aNodeToKeepIsFirst);

  /**
   *  Set aOffset to the offset of aChild in aParent.  
   *  Returns an error if aChild is not an immediate child of aParent.
   */
  static nsresult GetChildOffset(nsIDOMNode *aChild, 
                                 nsIDOMNode *aParent, 
                                 PRInt32    &aOffset);

  /**
   *  Set aParent to the parent of aChild.
   *  Set aOffset to the offset of aChild in aParent.  
   */
  static nsresult GetNodeLocation(nsIDOMNode *aChild, 
                                 nsCOMPtr<nsIDOMNode> *aParent, 
                                 PRInt32    *aOffset);

  /** set aIsInline to PR_TRUE if aNode is inline as defined by HTML DTD */
  static nsresult IsNodeInline(nsIDOMNode *aNode, PRBool &aIsInline);

  /** set aIsBlock to PR_TRUE if aNode is block as defined by HTML DTD */
  static nsresult IsNodeBlock(nsIDOMNode *aNode, PRBool &aIsBlock);

  /** This version is for exposure to JavaScript */
  NS_IMETHOD NodeIsBlock(nsIDOMNode *aNode, PRBool &aIsBlock);

  /** returns the closest block parent of aNode, not including aNode itself.
    * can return null, for example if aNode is in a document fragment.
    * @param aNode        The node whose parent we seek.
    * @param aBlockParent [OUT] The block parent, if any.
    * @return a success value unless an unexpected error occurs.
    */
  static nsresult GetBlockParent(nsIDOMNode     *aNode, 
                                 nsIDOMElement **aBlockParent);

  /** Determines the bounding nodes for the block section containing aNode.
    * The calculation is based on some nodes intrinsically being block elements
    * acording to HTML.  Style sheets are not considered in this calculation.
    * <BR> tags separate block content sections.  So the HTML markup:
    * <PRE>
    *      <P>text1<BR>text2<B>text3</B></P>
    * </PRE>
    * contains two block content sections.  The first has the text node "text1"
    * for both endpoints.  The second has "text2" as the left endpoint and
    * "text3" as the right endpoint.
    * Notice that offsets aren't required, only leaf nodes.  Offsets are implicit.
    *
    * @param aNode      the block content returned includes aNode
    * @param aLeftNode  [OUT] the left endpoint of the block content containing aNode
    * @param aRightNode [OUT] the right endpoint of the block content containing aNode
    *
    */
  static nsresult GetBlockSection(nsIDOMNode  *aNode,
                                  nsIDOMNode **aLeftNode, 
                                  nsIDOMNode **aRightNode);

  /** Compute the set of block sections in a given range.
    * A block section is the set of (leftNode, rightNode) pairs given
    * by GetBlockSection.  The set is computed by computing the 
    * block section for every leaf node in the range and throwing 
    * out duplicates.
    *
    * @param aRange     The range to compute block sections for.
    * @param aSections  Allocated storage for the resulting set, stored as nsIDOMRanges.
    */
  static nsresult GetBlockSectionsForRange(nsIDOMRange      *aRange, 
                                           nsISupportsArray *aSections);

  /** returns PR_TRUE in out-param aResult if all nodes between (aStartNode, aStartOffset)
    * and (aEndNode, aEndOffset) are inline as defined by HTML DTD. 
    */
  static nsresult IntermediateNodesAreInline(nsIDOMRange  *aRange,
                                             nsIDOMNode   *aStartNode, 
                                             PRInt32       aStartOffset, 
                                             nsIDOMNode   *aEndNode,
                                             PRInt32       aEndOffset,
                                             PRBool       &aResult);

  /** returns the number of things inside aNode in the out-param aCount.  
    * @param  aNode is the node to get the length of.  
    *         If aNode is text, returns number of characters. 
    *         If not, returns number of children nodes.
    * @param  aCount [OUT] the result of the above calculation.
    */
  static nsresult GetLengthOfDOMNode(nsIDOMNode *aNode, PRUint32 &aCount);

  /** get the node immediately prior to aCurrentNode
    * @param aCurrentNode   the node from which we start the search
    * @param aEditableNode  if PR_TRUE, only return an editable node
    * @param aResultNode    [OUT] the node that occurs before aCurrentNode in the tree,
    *                       skipping non-editable nodes if aEditableNode is PR_TRUE.
    *                       If there is no prior node, aResultNode will be nsnull.
    */
  nsresult GetPriorNode(nsIDOMNode  *aCurrentNode, 
                        PRBool       aEditableNode,
                        nsIDOMNode **aResultNode);

  // and another version that takes a {parent,offset} pair rather than a node
  nsresult GetPriorNode(nsIDOMNode  *aParentNode, 
                        PRInt32      aOffset, 
                        PRBool       aEditableNode, 
                        nsIDOMNode **aResultNode);
                       
  /** get the node immediately after to aCurrentNode
    * @param aCurrentNode   the node from which we start the search
    * @param aEditableNode  if PR_TRUE, only return an editable node
    * @param aResultNode    [OUT] the node that occurs after aCurrentNode in the tree,
    *                       skipping non-editable nodes if aEditableNode is PR_TRUE.
    *                       If there is no prior node, aResultNode will be nsnull.
    */
  nsresult GetNextNode(nsIDOMNode  *aCurrentNode, 
                       PRBool       aEditableNode,
                       nsIDOMNode **aResultNode);

  // and another version that takes a {parent,offset} pair rather than a node
  nsresult GetNextNode(nsIDOMNode  *aParentNode, 
                       PRInt32      aOffset, 
                       PRBool       aEditableNode, 
                       nsIDOMNode **aResultNode);
                       
  /** Get the rightmost child of aCurrentNode, and return it in aResultNode
    * aResultNode is set to nsnull if aCurrentNode has no children.
    */
  static nsresult GetRightmostChild(nsIDOMNode *aCurrentNode, nsIDOMNode **aResultNode);

  /** Get the leftmost child of aCurrentNode, and return it in aResultNode
    * aResultNode is set to nsnull if aCurrentNode has no children.
    */
  static nsresult GetLeftmostChild(nsIDOMNode *aCurrentNode, nsIDOMNode **aResultNode);

  /** GetFirstTextNode ADDREFFS and will get the next available text node from the passed
   *  in node parameter it can also return NS_ERROR_FAILURE if no text nodes are available
   *  now it simply returns the first node in the dom
   *  @param nsIDOMNode *aNode is the node to start looking from
   *  @param nsIDOMNode **aRetNode is the return location of the text dom node
   *
   * NOTE: this method will probably be removed.
   */
  static nsresult GetFirstTextNode(nsIDOMNode *aNode, nsIDOMNode **aRetNode);

  /** GetFirstNodeOfType ADDREFFS and will get the next available node from the passed
   *  in aStartNode parameter of type aTag.
   *  It can also return NS_ERROR_FAILURE if no such nodes are available
   *  @param   aStartNode is the node to start looking from
   *  @param   aTag is the type of node we are searching for
   *  @param   aResult is the node we found, or nsnull if there is none
   */
  static nsresult GetFirstNodeOfType(nsIDOMNode     *aStartNode, 
                                     const nsString &aTag, 
                                     nsIDOMNode    **aResult);

  /** returns PR_TRUE if aNode is of the type implied by aTag */
  static PRBool NodeIsType(nsIDOMNode *aNode, nsIAtom *aTag);

  /** returns PR_TRUE if aParent can contain a child of type aTag */
  PRBool CanContainTag(nsIDOMNode* aParent, const nsString &aTag);
  PRBool TagCanContain(const nsString &aParentTag, nsIDOMNode* aChild);
  PRBool TagCanContainTag(const nsString &aParentTag, const nsString &aChildTag);

  /** returns PR_TRUE if aNode is a container */
  PRBool IsContainer(nsIDOMNode *aNode);

  /** returns PR_TRUE if aNode is an editable node */
  PRBool IsEditable(nsIDOMNode *aNode);

  /** returns PR_TRUE if aNode is a MozEditorBogus node */
  PRBool IsMozEditorBogusNode(nsIDOMNode *aNode);

  /** returns PR_TRUE if content is an merely formatting whitespacce */
  PRBool IsEmptyTextContent(nsIContent* aContent);

  /** counts number of editable child nodes */
  nsresult CountEditableChildren(nsIDOMNode *aNode, PRUint32 &outCount);
  
  /** Find the deep first and last children. Returned nodes are AddReffed */
  nsresult GetFirstEditableNode(nsIDOMNode *aRoot, nsCOMPtr<nsIDOMNode> *outFirstNode);
  nsresult GetLastEditableNode(nsIDOMNode *aRoot, nsCOMPtr<nsIDOMNode> *outLastNode);


  /** from html rules code - migration in progress */
  static nsresult GetTagString(nsIDOMNode *aNode, nsString& outString);
  static nsCOMPtr<nsIAtom> GetTag(nsIDOMNode *aNode);
  static PRBool NodesSameType(nsIDOMNode *aNode1, nsIDOMNode *aNode2);
  static PRBool IsBlockNode(nsIDOMNode *aNode);
  static PRBool IsInlineNode(nsIDOMNode *aNode);
  static nsCOMPtr<nsIDOMNode> GetBlockNodeParent(nsIDOMNode *aNode);
  static PRBool HasSameBlockNodeParent(nsIDOMNode *aNode1, nsIDOMNode *aNode2);
  
  static PRBool IsTextOrElementNode(nsIDOMNode *aNode);
  static PRBool IsTextNode(nsIDOMNode *aNode);
  
  static PRInt32 GetIndexOf(nsIDOMNode *aParent, nsIDOMNode *aChild);
  static nsCOMPtr<nsIDOMNode> GetChildAt(nsIDOMNode *aParent, PRInt32 aOffset);
  
  static nsCOMPtr<nsIDOMNode> NextNodeInBlock(nsIDOMNode *aNode, IterDirection aDir);
  static nsresult GetStartNodeAndOffset(nsIDOMSelection *aSelection, nsCOMPtr<nsIDOMNode> *outStartNode, PRInt32 *outStartOffset);
  static nsresult GetEndNodeAndOffset(nsIDOMSelection *aSelection, nsCOMPtr<nsIDOMNode> *outEndNode, PRInt32 *outEndOffset);

  nsresult IsPreformatted(nsIDOMNode *aNode, PRBool *aResult);
  nsresult IsNextCharWhitespace(nsIDOMNode *aParentNode, 
                                PRInt32 aOffset, 
                                PRBool *outIsSpace, 
                                PRBool *outIsNBSP,
                                nsCOMPtr<nsIDOMNode> *outNode = 0,
                                PRInt32 *outOffset = 0);
  nsresult IsPrevCharWhitespace(nsIDOMNode *aParentNode, 
                                PRInt32 aOffset, 
                                PRBool *outIsSpace, 
                                PRBool *outIsNBSP,
                                nsCOMPtr<nsIDOMNode> *outNode = 0,
                                PRInt32 *outOffset = 0);

  nsresult SplitNodeDeep(nsIDOMNode *aNode, nsIDOMNode *aSplitPointParent, PRInt32 aSplitPointOffset, PRInt32 *outOffset);
  nsresult JoinNodeDeep(nsIDOMNode *aLeftNode, nsIDOMNode *aRightNode, nsCOMPtr<nsIDOMNode> *aOutJoinNode, PRInt32 *outOffset); 

  nsresult GetString(const nsString& name, nsString& value);

  nsresult BeginUpdateViewBatch(void);
  nsresult EndUpdateViewBatch(void);

  PRBool GetShouldTxnSetSelection();
  void   SetShouldTxnSetSelection(PRBool aShould);

protected:

  PRUint32        mFlags;		// behavior flags. See nsIHTMLEditor.h for the flags we use.
  
  nsWeakPtr       mPresShellWeak;   // weak reference to the nsIPresShell
  nsIViewManager *mViewManager;
  PRInt32         mUpdateCount;
  nsCOMPtr<nsITransactionManager> mTxnMgr;
  nsCOMPtr<nsIEditProperty>  mEditProperty;
  nsCOMPtr<nsICSSStyleSheet> mLastStyleSheet;			// is owning this dangerous?
  nsWeakPtr       mPlaceHolderTxn;     // weak reference to placeholder for begin/end batch purposes
  nsIAtom        *mPlaceHolderName;    // name of placeholder transaction
  PRInt32         mPlaceHolderBatch;   // nesting count for batching
  nsSelectionState *mSelState;          // saved selection state for placeholder txn batching
  PRBool          mShouldTxnSetSelection;  // turn off for conservative selection adjustment by txns
  nsCOMPtr<nsIDOMElement> mBodyElement;    // cached body node
  //
  // data necessary to build IME transactions
  //
  PRBool						mInIMEMode;          // are we inside an IME composition?
  nsIPrivateTextRangeList*      mIMETextRangeList;   // IME special selection ranges
  nsCOMPtr<nsIDOMCharacterData> mIMETextNode;        // current IME text node
  PRUint32						mIMETextOffset;      // offset in text node where IME comp string begins
  PRUint32						mIMEBufferLength;    // current length of IME comp string

  nsVoidArray*                  mActionListeners;
  nsCOMPtr<nsISupportsArray>    mDocStateListeners;

  PRInt8                        mDocDirtyState;		// -1 = not initialized

  nsWeakPtr        mDocWeak;  // weak reference to the nsIDOMDocument
  nsCOMPtr<nsIDTD> mDTD;

  static PRInt32 gInstanceCount;

  friend PRBool NSCanUnload(nsISupports* serviceMgr);
  friend class nsAutoTxnsConserveSelection;
};


#endif