layout/base/nsLayoutHistoryState.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Pierre Phaneuf <pp@ludusdesign.com>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
  27  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
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  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 /*
  40  * container for information saved in session history when the document
  41  * is not
  42  */
  43
  44 #include "nsILayoutHistoryState.h"
  45 #include "nsWeakReference.h"
  46 #include "nsClassHashtable.h"
  47 #include "nsPresState.h"
  48
  49 class nsLayoutHistoryState : public nsILayoutHistoryState,
  50                              public nsSupportsWeakReference
  51 {
  52 public:
  53   NS_HIDDEN_(nsresult) Init();
  54
  55   NS_DECL_ISUPPORTS
  56
  57   // nsILayoutHistoryState
  58   NS_IMETHOD AddState(const nsCString& aKey, nsPresState* aState);
  59   NS_IMETHOD GetState(const nsCString& aKey, nsPresState** aState);
  60   NS_IMETHOD RemoveState(const nsCString& aKey);
  61   NS_IMETHOD_(PRBool) HasStates() const;
  62   NS_IMETHOD SetScrollPositionOnly(const PRBool aFlag);
  63
  64
  65 private:
  66   ~nsLayoutHistoryState() {}
  67   PRBool mScrollPositionOnly;
  68
  69   nsClassHashtable<nsCStringHashKey,nsPresState> mStates;
  70 };
  71
  72
  73 nsresult
  74 NS_NewLayoutHistoryState(nsILayoutHistoryState** aState)
  75 {
  76   nsLayoutHistoryState *state;
  77
  78   *aState = nsnull;
  79   state = new nsLayoutHistoryState();
  80   if (!state)
  81     return NS_ERROR_OUT_OF_MEMORY;
  82
  83   NS_ADDREF(state);
  84   nsresult rv = state->Init();
  85   if (NS_SUCCEEDED(rv))
  86     *aState = state;
  87   else
  88     NS_RELEASE(state);
  89
  90   return rv;
  91 }
  92
  93 NS_IMPL_ISUPPORTS2(nsLayoutHistoryState,
  94                    nsILayoutHistoryState,
  95                    nsISupportsWeakReference)
  96
  97 nsresult
  98 nsLayoutHistoryState::Init()
  99 {
 100   mScrollPositionOnly = PR_FALSE;
 101   return mStates.Init() ? NS_OK : NS_ERROR_FAILURE;
 102 }
 103
 104 NS_IMETHODIMP
 105 nsLayoutHistoryState::AddState(const nsCString& aStateKey, nsPresState* aState)
 106 {
 107   return mStates.Put(aStateKey, aState) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 108 }
 109
 110 NS_IMETHODIMP
 111 nsLayoutHistoryState::GetState(const nsCString& aKey, nsPresState** aState)
 112 {
 113   PRBool entryExists = mStates.Get(aKey, aState);
 114
 115   if (entryExists && mScrollPositionOnly) {
 116     // Ensure any state that shouldn't be restored is removed
 117     (*aState)->ClearNonScrollState();
 118   }
 119
 120   return NS_OK;
 121 }
 122
 123 NS_IMETHODIMP
 124 nsLayoutHistoryState::RemoveState(const nsCString& aKey)
 125 {
 126   mStates.Remove(aKey);
 127   return NS_OK;
 128 }
 129
 130 NS_IMETHODIMP_(PRBool)
 131 nsLayoutHistoryState::HasStates() const
 132 {
 133   return mStates.Count() != 0;
 134 }
 135
 136 NS_IMETHODIMP
 137 nsLayoutHistoryState::SetScrollPositionOnly(const PRBool aFlag)
 138 {
 139   mScrollPositionOnly = aFlag;
 140   return NS_OK;
 141 }