gecko-dev/htmlparser/src/nsIDTD.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 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 *
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */

/**
 * MODULE NOTES:
 * @update  gess 4/8/98
 * 
 *         
 */

#ifndef NS_IDTD__
#define NS_IDTD__

#include "nsISupports.h"
#include "prtypes.h"
#include "nsString.h"

#define NS_IDTD_IID      \
  {0x75634940, 0xcfdc,  0x11d1,  \
  {0xaa, 0xda, 0x00,    0x80, 0x5f, 0x8a, 0x3e, 0x14}}



class nsIDTD : public nsISupports {
            
  public:

    /**
     *  This method is called to determine whether or not a tag
     *  of one type can contain a tag of another type.
     *  
     *  @update  gess 3/25/98
     *  @param   aParent -- tag enum of parent container
     *  @param   aChild -- tag enum of child container
     *  @return  PR_TRUE if parent can contain child
     */
    virtual PRBool  CanContain(PRInt32 aParent,PRInt32 aChild) const =0;

    /**
     *  This method is called to determine whether or not a tag
     *  of one type can contain a tag of another type.
     *  
     *  @update  gess 3/25/98
     *  @param   aParent -- tag enum of parent container
     *  @param   aChild -- tag enum of child container
     *  @return  PR_TRUE if parent can contain child
     */
    virtual PRBool  CanContainIndirect(PRInt32 aParent,PRInt32 aChild) const=0;

    /**
     *  This method gets called to determine whether a given 
     *  tag is itself a container
     *  
     *  @update  gess 3/25/98
     *  @param   aTag -- tag to test for containership
     *  @return  PR_TRUE if given tag can contain other tags
     */
    virtual PRBool  IsContainer(PRInt32 aTags)const=0;

    /**
     *  This method gets called to determine whether a given 
     *  tag can contain newlines. Most do not.
     *  
     *  @update  gess 3/25/98
     *  @param   aParent -- tag type of parent
     *  @param   aChild -- tag type of child
     *  @return  PR_TRUE if given tag can contain other tags
     */
    virtual PRBool CanOmit(PRInt32 aParent,PRInt32 aChild)const=0;

    /**
     * This method gets called at various times by the parser
     * whenever we want to verify a valid context stack. This
     * method also gives us a hook to add debugging metrics.
     *
     * @update  gess4/6/98
     * @param   aStack[] array of ints (tokens)
     * @param   aCount number of elements in given array
     * @return  TRUE if stack is valid, else FALSE
     */
    virtual PRBool VerifyContextVector(PRInt32* aStack,PRInt32 aCount) const=0;

    /**
     * This method does two things: 1st, help construct
     * our own internal model of the content-stack; and
     * 2nd, pass this message on to the sink.
     *
     * @update  gess4/6/98
     * @param   aNode -- next node to be added to model
     * @return  TRUE if ok, FALSE if error
     */
    virtual PRInt32 GetDefaultParentTagFor(PRInt32 aTag) const=0;

    /**
     * This method tries to design a context map (without actually
     * changing our parser state) from the parent down to the
     * child. 
     *
     * @update  gess4/6/98
     * @param   aParent -- tag type of parent
     * @param   aChild -- tag type of child
     * @return  True if closure was achieved -- other false
     */
    virtual PRBool ForwardPropagate(nsString& aVector,PRInt32 aParentTag,PRInt32 aChildTag) const=0;

    /**
     * This method tries to design a context map (without actually
     * changing our parser state) from the child up to the parent.
     *
     * @update  gess4/6/98
     * @param   aParent -- tag type of parent
     * @param   aChild -- tag type of child
     * @return  True if closure was achieved -- other false
     */
    virtual PRBool BackwardPropagate(nsString& aVector,PRInt32 aParentTag,PRInt32 aChildTag) const=0;

};


#endif