xpcom/ds/nsStringEnumerator.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 String Enumerator.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corp.
  19  * Portions created by the Initial Developer are Copyright (C) 2003
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Alec Flett <alecf@netscape.com>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * 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
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  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 #include "nsStringEnumerator.h"
  41 #include "prtypes.h"
  42 #include "nsCRT.h"
  43 #include "nsString.h"
  44 #include "nsReadableUtils.h"
  45 #include "nsISimpleEnumerator.h"
  46 #include "nsSupportsPrimitives.h"
  47
  48 //
  49 // nsStringEnumerator
  50 //
  51
  52 class nsStringEnumerator : public nsIStringEnumerator,
  53                            public nsIUTF8StringEnumerator,
  54                            public nsISimpleEnumerator
  55 {
  56 public:
  57     nsStringEnumerator(const nsTArray<nsString>* aArray, PRBool aOwnsArray) :
  58         mArray(aArray), mIndex(0), mOwnsArray(aOwnsArray), mIsUnicode(PR_TRUE)
  59     {}
  60
  61     nsStringEnumerator(const nsTArray<nsCString>* aArray, PRBool aOwnsArray) :
  62         mCArray(aArray), mIndex(0), mOwnsArray(aOwnsArray), mIsUnicode(PR_FALSE)
  63     {}
  64
  65     nsStringEnumerator(const nsTArray<nsString>* aArray, nsISupports* aOwner) :
  66         mArray(aArray), mIndex(0), mOwner(aOwner), mOwnsArray(PR_FALSE), mIsUnicode(PR_TRUE)
  67     {}
  68
  69     nsStringEnumerator(const nsTArray<nsCString>* aArray, nsISupports* aOwner) :
  70         mCArray(aArray), mIndex(0), mOwner(aOwner), mOwnsArray(PR_FALSE), mIsUnicode(PR_FALSE)
  71     {}
  72
  73     NS_DECL_ISUPPORTS
  74     NS_DECL_NSIUTF8STRINGENUMERATOR
  75
  76     // have to declare nsIStringEnumerator manually, because of
  77     // overlapping method names
  78     NS_IMETHOD GetNext(nsAString& aResult);
  79     NS_DECL_NSISIMPLEENUMERATOR
  80
  81 private:
  82     ~nsStringEnumerator() {
  83         if (mOwnsArray) {
  84             // const-casting is safe here, because the NS_New*
  85             // constructors make sure mOwnsArray is consistent with
  86             // the constness of the objects
  87             if (mIsUnicode)
  88                 delete const_cast<nsTArray<nsString>*>(mArray);
  89             else
  90                 delete const_cast<nsTArray<nsCString>*>(mCArray);
  91         }
  92     }
  93
  94     union {
  95         const nsTArray<nsString>* mArray;
  96         const nsTArray<nsCString>* mCArray;
  97     };
  98
  99     inline PRUint32 Count() {
 100         return mIsUnicode ? mArray->Length() : mCArray->Length();
 101     }
 102
 103     PRUint32 mIndex;
 104
 105     // the owner allows us to hold a strong reference to the object
 106     // that owns the array. Having a non-null value in mOwner implies
 107     // that mOwnsArray is PR_FALSE, because we rely on the real owner
 108     // to release the array
 109     nsCOMPtr<nsISupports> mOwner;
 110     PRPackedBool mOwnsArray;
 111     PRPackedBool mIsUnicode;
 112 };
 113
 114 NS_IMPL_ISUPPORTS3(nsStringEnumerator,
 115                    nsIStringEnumerator,
 116                    nsIUTF8StringEnumerator,
 117                    nsISimpleEnumerator)
 118
 119 NS_IMETHODIMP
 120 nsStringEnumerator::HasMore(PRBool* aResult)
 121 {
 122     NS_ENSURE_ARG_POINTER(aResult);
 123     *aResult = mIndex < Count();
 124     return NS_OK;
 125 }
 126
 127 NS_IMETHODIMP
 128 nsStringEnumerator::HasMoreElements(PRBool* aResult)
 129 {
 130     return HasMore(aResult);
 131 }
 132
 133 NS_IMETHODIMP
 134 nsStringEnumerator::GetNext(nsISupports** aResult)
 135 {
 136     if (mIsUnicode) {
 137         nsSupportsStringImpl* stringImpl = new nsSupportsStringImpl();
 138         if (!stringImpl) return NS_ERROR_OUT_OF_MEMORY;
 139
 140         stringImpl->SetData(mArray->ElementAt(mIndex++));
 141         *aResult = stringImpl;
 142     }
 143     else {
 144         nsSupportsCStringImpl* cstringImpl = new nsSupportsCStringImpl();
 145         if (!cstringImpl) return NS_ERROR_OUT_OF_MEMORY;
 146
 147         cstringImpl->SetData(mCArray->ElementAt(mIndex++));
 148         *aResult = cstringImpl;
 149     }
 150     NS_ADDREF(*aResult);
 151     return NS_OK;
 152 }
 153
 154 NS_IMETHODIMP
 155 nsStringEnumerator::GetNext(nsAString& aResult)
 156 {
 157     NS_ENSURE_TRUE(mIndex < Count(), NS_ERROR_UNEXPECTED);
 158
 159     if (mIsUnicode)
 160         aResult = mArray->ElementAt(mIndex++);
 161     else
 162         CopyUTF8toUTF16(mCArray->ElementAt(mIndex++), aResult);
 163
 164     return NS_OK;
 165 }
 166
 167 NS_IMETHODIMP
 168 nsStringEnumerator::GetNext(nsACString& aResult)
 169 {
 170     NS_ENSURE_TRUE(mIndex < Count(), NS_ERROR_UNEXPECTED);
 171
 172     if (mIsUnicode)
 173         CopyUTF16toUTF8(mArray->ElementAt(mIndex++), aResult);
 174     else
 175         aResult = mCArray->ElementAt(mIndex++);
 176
 177     return NS_OK;
 178 }
 179
 180 template<class T>
 181 static inline nsresult
 182 StringEnumeratorTail(T** aResult NS_INPARAM)
 183 {
 184     if (!*aResult)
 185         return NS_ERROR_OUT_OF_MEMORY;
 186     NS_ADDREF(*aResult);
 187     return NS_OK;
 188 }
 189
 190 //
 191 // constructors
 192 //
 193
 194 NS_COM nsresult
 195 NS_NewStringEnumerator(nsIStringEnumerator** aResult,
 196                        const nsTArray<nsString>* aArray, nsISupports* aOwner)
 197 {
 198     NS_ENSURE_ARG_POINTER(aResult);
 199     NS_ENSURE_ARG_POINTER(aArray);
 200
 201     *aResult = new nsStringEnumerator(aArray, aOwner);
 202     return StringEnumeratorTail(aResult);
 203 }
 204
 205
 206 NS_COM nsresult
 207 NS_NewUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
 208                            const nsTArray<nsCString>* aArray, nsISupports* aOwner)
 209 {
 210     NS_ENSURE_ARG_POINTER(aResult);
 211     NS_ENSURE_ARG_POINTER(aArray);
 212
 213     *aResult = new nsStringEnumerator(aArray, aOwner);
 214     return StringEnumeratorTail(aResult);
 215 }
 216
 217 NS_COM nsresult
 218 NS_NewAdoptingStringEnumerator(nsIStringEnumerator** aResult,
 219                                nsTArray<nsString>* aArray)
 220 {
 221     NS_ENSURE_ARG_POINTER(aResult);
 222     NS_ENSURE_ARG_POINTER(aArray);
 223
 224     *aResult = new nsStringEnumerator(aArray, PR_TRUE);
 225     return StringEnumeratorTail(aResult);
 226 }
 227
 228 NS_COM nsresult
 229 NS_NewAdoptingUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
 230                                    nsTArray<nsCString>* aArray)
 231 {
 232     NS_ENSURE_ARG_POINTER(aResult);
 233     NS_ENSURE_ARG_POINTER(aArray);
 234
 235     *aResult = new nsStringEnumerator(aArray, PR_TRUE);
 236     return StringEnumeratorTail(aResult);
 237 }
 238
 239 // const ones internally just forward to the non-const equivalents
 240 NS_COM nsresult
 241 NS_NewStringEnumerator(nsIStringEnumerator** aResult,
 242                        const nsTArray<nsString>* aArray)
 243 {
 244     NS_ENSURE_ARG_POINTER(aResult);
 245     NS_ENSURE_ARG_POINTER(aArray);
 246
 247     *aResult = new nsStringEnumerator(aArray, PR_FALSE);
 248     return StringEnumeratorTail(aResult);
 249 }
 250
 251 NS_COM nsresult
 252 NS_NewUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
 253                            const nsTArray<nsCString>* aArray)
 254 {
 255     NS_ENSURE_ARG_POINTER(aResult);
 256     NS_ENSURE_ARG_POINTER(aArray);
 257
 258     *aResult = new nsStringEnumerator(aArray, PR_FALSE);
 259     return StringEnumeratorTail(aResult);
 260 }
 261