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nsSVGValue.h
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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 the Mozilla SVG project.
00016  *
00017  * The Initial Developer of the Original Code is
00018  * Crocodile Clips Ltd..
00019  * Portions created by the Initial Developer are Copyright (C) 2001
00020  * the Initial Developer. All Rights Reserved.
00021  *
00022  * Contributor(s):
00023  *   Alex Fritze <alex.fritze@crocodile-clips.com> (original author)
00024  *
00025  * Alternatively, the contents of this file may be used under the terms of
00026  * either of the GNU General Public License Version 2 or later (the "GPL"),
00027  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00028  * in which case the provisions of the GPL or the LGPL are applicable instead
00029  * of those above. If you wish to allow use of your version of this file only
00030  * under the terms of either the GPL or the LGPL, and not to allow others to
00031  * use your version of this file under the terms of the MPL, indicate your
00032  * decision by deleting the provisions above and replace them with the notice
00033  * and other provisions required by the GPL or the LGPL. If you do not delete
00034  * the provisions above, a recipient may use your version of this file under
00035  * the terms of any one of the MPL, the GPL or the LGPL.
00036  *
00037  * ***** END LICENSE BLOCK ***** */
00038 
00039 #ifndef __NS_SVGVALUE_H__
00040 #define __NS_SVGVALUE_H__
00041 
00042 #include "nscore.h"
00043 #include "nsISVGValue.h"
00044 #include "nsAutoPtr.h"
00045 #include "nsVoidArray.h"
00046 #include "nsISVGValueObserver.h"
00047 
00048 class nsSVGValue : public nsISVGValue
00049 {
00050 protected:
00051   nsSVGValue();
00052   virtual ~nsSVGValue();
00053 
00054   // to be called by subclass whenever value is being modified.
00055   // nested calls will be ignored, so calls need to be balanced
00056   void WillModify(modificationType aModType = mod_other);
00057   void DidModify(modificationType aModType = mod_other);
00058 
00059   friend class nsSVGValueAutoNotifier;
00060   
00061 public:
00062   // Partial Implementation of nsISVGValue interface:
00063   NS_IMETHOD AddObserver(nsISVGValueObserver* observer);
00064   NS_IMETHOD RemoveObserver(nsISVGValueObserver* observer);
00065   NS_IMETHOD BeginBatchUpdate();
00066   NS_IMETHOD EndBatchUpdate();
00067 
00068   typedef
00069   NS_STDCALL_FUNCPROTO(nsresult,
00070                        SVGObserverNotifyFunction,
00071                        nsISVGValueObserver, DidModifySVGObservable,
00072                        (nsISVGValue*, nsISVGValue::modificationType));
00073 
00074 protected:
00075   // implementation helpers
00076   void ReleaseObservers();
00077   void NotifyObservers(SVGObserverNotifyFunction f,
00078                        modificationType aModType);
00079   PRInt32 GetModifyNestCount() { return mModifyNestCount; }
00080 private:
00081   virtual void OnDidModify(){}; // hook that will be called before observers are notified
00082   
00083   nsSmallVoidArray mObservers;
00084   PRInt32 mModifyNestCount;
00085 };
00086 
00087 // Class that will automatically call WillModify and DidModify in its ctor
00088 // and dtor respectively (for functions that have multiple exit points).
00089 
00090 class nsSVGValueAutoNotifier
00091 {
00092 public:
00093   nsSVGValueAutoNotifier(nsSVGValue* aVal,
00094                          nsISVGValue::modificationType aModType =
00095                          nsISVGValue::mod_other)
00096     : mVal(aVal)
00097     , mModType(aModType)
00098   {
00099     mVal->WillModify(mModType);
00100   }
00101 
00102   ~nsSVGValueAutoNotifier()
00103   {
00104     mVal->DidModify(mModType);
00105   }
00106 
00107 private:
00108   nsRefPtr<nsSVGValue> mVal;
00109   nsISVGValue::modificationType mModType;
00110 };
00111 
00112 #endif //__NS_SVGVALUE_H__