content/xul/templates/src/nsXULTemplateResultSetRDF.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   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 Neil Deakin
  18  * Portions created by the Initial Developer are Copyright (C) 2005
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *
  23  * Alternatively, the contents of this file may be used under the terms of
  24  * either of the GNU General Public License Version 2 or later (the "GPL"),
  25  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  26  * in which case the provisions of the GPL or the LGPL are applicable instead
  27  * of those above. If you wish to allow use of your version of this file only
  28  * under the terms of either the GPL or the LGPL, and not to allow others to
  29  * use your version of this file under the terms of the MPL, indicate your
  30  * decision by deleting the provisions above and replace them with the notice
  31  * and other provisions required by the GPL or the LGPL. If you do not delete
  32  * the provisions above, a recipient may use your version of this file under
  33  * the terms of any one of the MPL, the GPL or the LGPL.
  34  *
  35  * ***** END LICENSE BLOCK ***** */
  36
  37 #include "nsXULTemplateResultSetRDF.h"
  38 #include "nsXULTemplateQueryProcessorRDF.h"
  39
  40 NS_IMPL_ISUPPORTS1(nsXULTemplateResultSetRDF, nsISimpleEnumerator)
  41
  42 NS_IMETHODIMP
  43 nsXULTemplateResultSetRDF::HasMoreElements(PRBool *aResult)
  44 {
  45     *aResult = PR_TRUE;
  46
  47     nsCOMPtr<nsIRDFNode> node;
  48
  49     if (! mInstantiations || ! mQuery) {
  50         *aResult = PR_FALSE;
  51         return NS_OK;
  52     }
  53
  54     if (mCheckedNext) {
  55         if (!mCurrent || mCurrent == &(mInstantiations->mHead))
  56             *aResult = PR_FALSE;
  57         return NS_OK;
  58     }
  59
  60     mCheckedNext = PR_TRUE;
  61
  62     do {
  63         if (mCurrent) {
  64             mCurrent = mCurrent->mNext;
  65             if (mCurrent == &(mInstantiations->mHead)) {
  66                 *aResult = PR_FALSE;
  67                 return NS_OK;
  68             }
  69         }
  70         else {
  71             *aResult = ! mInstantiations->Empty();
  72             if (*aResult)
  73                 mCurrent = mInstantiations->mHead.mNext;
  74         }
  75
  76         // get the value of the member variable. If it is not set, skip
  77         // the result and move on to the next result
  78         if (mCurrent) {
  79             mCurrent->mInstantiation.mAssignments.
  80                 GetAssignmentFor(mQuery->mMemberVariable, getter_AddRefs(node));
  81         }
  82
  83         // only resources may be used as results
  84         mResource = do_QueryInterface(node);
  85     } while (! mResource);
  86
  87     return NS_OK;
  88 }
  89
  90 NS_IMETHODIMP
  91 nsXULTemplateResultSetRDF::GetNext(nsISupports **aResult)
  92 {
  93     if (!aResult)
  94         return NS_ERROR_NULL_POINTER;
  95
  96     if (!mCurrent || !mCheckedNext)
  97         return NS_ERROR_FAILURE;
  98
  99     nsRefPtr<nsXULTemplateResultRDF> nextresult =
 100         new nsXULTemplateResultRDF(mQuery, mCurrent->mInstantiation, mResource);
 101     if (!nextresult)
 102         return NS_ERROR_OUT_OF_MEMORY;
 103
 104     // add the supporting memory elements to the processor's map. These are
 105     // used to remove the results when an assertion is removed from the graph
 106     mProcessor->AddMemoryElements(mCurrent->mInstantiation, nextresult);
 107
 108     mCheckedNext = PR_FALSE;
 109
 110     *aResult = nextresult;
 111     NS_ADDREF(*aResult);
 112
 113     return NS_OK;
 114 }