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lightning-sunbird  0.9+nobinonly
nsFrameNavigator.cpp
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00001 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
00003  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00004  *
00005  * The contents of this file are subject to the Mozilla Public License Version
00006  * 1.1 (the "License"); you may not use this file except in compliance with
00007  * the License. You may obtain a copy of the License at
00008  * http://www.mozilla.org/MPL/
00009  *
00010  * Software distributed under the License is distributed on an "AS IS" basis,
00011  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00012  * for the specific language governing rights and limitations under the
00013  * License.
00014  *
00015  * The Original Code is Mozilla Communicator client code.
00016  *
00017  * The Initial Developer of the Original Code is
00018  * Netscape Communications Corporation.
00019  * Portions created by the Initial Developer are Copyright (C) 1998
00020  * the Initial Developer. All Rights Reserved.
00021  *
00022  * Contributor(s):
00023  *
00024  * Alternatively, the contents of this file may be used under the terms of
00025  * either of the GNU General Public License Version 2 or later (the "GPL"),
00026  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00027  * in which case the provisions of the GPL or the LGPL are applicable instead
00028  * of those above. If you wish to allow use of your version of this file only
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00036  * ***** END LICENSE BLOCK ***** */
00037 
00038 //
00039 // Eric Vaughan
00040 // Netscape Communications
00041 //
00042 // See documentation in associated header file
00043 //
00044 
00045 #include "nsFrameNavigator.h"
00046 #include "nsCOMPtr.h"
00047 #include "nsIContent.h"
00048 #include "nsIFrame.h"
00049 
00050 nsIBox*
00051 nsFrameNavigator::GetChildBeforeAfter(nsPresContext* aPresContext,
00052                                       nsIBox* start, PRBool before)
00053 {
00054    nsIBox* parent = nsnull;
00055    start->GetParentBox(&parent);
00056    PRInt32 index = IndexOf(aPresContext, parent,start);
00057    PRInt32 count = CountFrames(aPresContext, parent);
00058 
00059    if (index == -1) 
00060      return nsnull;
00061 
00062    if (before) {
00063      if (index == 0) {
00064          return nsnull;
00065      }
00066 
00067      return GetChildAt(aPresContext, parent, index-1);
00068    }
00069 
00070 
00071    if (index == count-1)
00072        return nsnull;
00073 
00074    return GetChildAt(aPresContext, parent, index+1);
00075 }
00076 
00077 PRInt32
00078 nsFrameNavigator::IndexOf(nsPresContext* aPresContext, nsIBox* parent, nsIBox* child)
00079 {
00080   PRInt32 count = 0;
00081 
00082   nsIBox* box = nsnull;
00083   parent->GetChildBox(&box); 
00084   while (nsnull != box) 
00085   {    
00086     if (box == child)
00087        return count;
00088 
00089     nsresult rv = box->GetNextBox(&box);
00090     NS_ASSERTION(rv == NS_OK,"failed to get next child");
00091     count++;
00092   }
00093 
00094   return -1;
00095 }
00096 
00097 PRInt32
00098 nsFrameNavigator::CountFrames(nsPresContext* aPresContext, nsIBox* aBox)
00099 {
00100   PRInt32 count = 0;
00101 
00102   nsIBox* box;
00103   aBox->GetChildBox(&box); 
00104   while (nsnull != box) 
00105   {    
00106     nsresult rv = box->GetNextBox(&box);
00107     NS_ASSERTION(rv == NS_OK,"failed to get next child");
00108     count++;
00109   }
00110 
00111   return count;
00112 }
00113 
00114 nsIBox*
00115 nsFrameNavigator::GetChildAt(nsPresContext* aPresContext, nsIBox* parent, PRInt32 index)
00116 {
00117   PRInt32 count = 0;
00118 
00119   nsIBox* box;
00120   parent->GetChildBox(&box); 
00121   while (nsnull != box) 
00122   {    
00123     if (count == index)
00124        return box;
00125 
00126     nsresult rv = box->GetNextBox(&box);
00127     NS_ASSERTION(rv == NS_OK,"failed to get next child");
00128     count++;
00129   }
00130 
00131   return nsnull;
00132 }
00133