xpcom/ds/nsStringEnumerator.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6
   7 #include "nsStringEnumerator.h"
   8 #include "nsISimpleEnumerator.h"
   9 #include "nsSupportsPrimitives.h"
  10 #include "mozilla/Attributes.h"
  11 #include "nsTArray.h"
  12
  13 //
  14 // nsStringEnumerator
  15 //
  16
  17 class nsStringEnumerator MOZ_FINAL
  18   : public nsIStringEnumerator
  19   , public nsIUTF8StringEnumerator
  20   , public nsISimpleEnumerator
  21 {
  22 public:
  23   nsStringEnumerator(const nsTArray<nsString>* aArray, bool aOwnsArray)
  24     : mArray(aArray)
  25     , mIndex(0)
  26     , mOwnsArray(aOwnsArray)
  27     , mIsUnicode(true)
  28   {}
  29
  30   nsStringEnumerator(const nsTArray<nsCString>* aArray, bool aOwnsArray)
  31     : mCArray(aArray)
  32     , mIndex(0)
  33     , mOwnsArray(aOwnsArray)
  34     , mIsUnicode(false)
  35   {}
  36
  37   nsStringEnumerator(const nsTArray<nsString>* aArray, nsISupports* aOwner)
  38     : mArray(aArray)
  39     , mIndex(0)
  40     , mOwner(aOwner)
  41     , mOwnsArray(false)
  42     , mIsUnicode(true)
  43   {}
  44
  45   nsStringEnumerator(const nsTArray<nsCString>* aArray, nsISupports* aOwner)
  46     : mCArray(aArray)
  47     , mIndex(0)
  48     , mOwner(aOwner)
  49     , mOwnsArray(false)
  50     , mIsUnicode(false)
  51   {}
  52
  53   NS_DECL_ISUPPORTS
  54   NS_DECL_NSIUTF8STRINGENUMERATOR
  55
  56   // have to declare nsIStringEnumerator manually, because of
  57   // overlapping method names
  58   NS_IMETHOD GetNext(nsAString& aResult);
  59   NS_DECL_NSISIMPLEENUMERATOR
  60
  61 private:
  62   ~nsStringEnumerator()
  63   {
  64     if (mOwnsArray) {
  65       // const-casting is safe here, because the NS_New*
  66       // constructors make sure mOwnsArray is consistent with
  67       // the constness of the objects
  68       if (mIsUnicode) {
  69         delete const_cast<nsTArray<nsString>*>(mArray);
  70       } else {
  71         delete const_cast<nsTArray<nsCString>*>(mCArray);
  72       }
  73     }
  74   }
  75
  76   union
  77   {
  78     const nsTArray<nsString>* mArray;
  79     const nsTArray<nsCString>* mCArray;
  80   };
  81
  82   inline uint32_t Count()
  83   {
  84     return mIsUnicode ? mArray->Length() : mCArray->Length();
  85   }
  86
  87   uint32_t mIndex;
  88
  89   // the owner allows us to hold a strong reference to the object
  90   // that owns the array. Having a non-null value in mOwner implies
  91   // that mOwnsArray is false, because we rely on the real owner
  92   // to release the array
  93   nsCOMPtr<nsISupports> mOwner;
  94   bool mOwnsArray;
  95   bool mIsUnicode;
  96 };
  97
  98 NS_IMPL_ISUPPORTS(nsStringEnumerator,
  99                   nsIStringEnumerator,
 100                   nsIUTF8StringEnumerator,
 101                   nsISimpleEnumerator)
 102
 103 NS_IMETHODIMP
 104 nsStringEnumerator::HasMore(bool* aResult)
 105 {
 106   *aResult = mIndex < Count();
 107   return NS_OK;
 108 }
 109
 110 NS_IMETHODIMP
 111 nsStringEnumerator::HasMoreElements(bool* aResult)
 112 {
 113   return HasMore(aResult);
 114 }
 115
 116 NS_IMETHODIMP
 117 nsStringEnumerator::GetNext(nsISupports** aResult)
 118 {
 119   if (mIsUnicode) {
 120     nsSupportsStringImpl* stringImpl = new nsSupportsStringImpl();
 121     if (!stringImpl) {
 122       return NS_ERROR_OUT_OF_MEMORY;
 123     }
 124
 125     stringImpl->SetData(mArray->ElementAt(mIndex++));
 126     *aResult = stringImpl;
 127   } else {
 128     nsSupportsCStringImpl* cstringImpl = new nsSupportsCStringImpl();
 129     if (!cstringImpl) {
 130       return NS_ERROR_OUT_OF_MEMORY;
 131     }
 132
 133     cstringImpl->SetData(mCArray->ElementAt(mIndex++));
 134     *aResult = cstringImpl;
 135   }
 136   NS_ADDREF(*aResult);
 137   return NS_OK;
 138 }
 139
 140 NS_IMETHODIMP
 141 nsStringEnumerator::GetNext(nsAString& aResult)
 142 {
 143   if (NS_WARN_IF(mIndex >= Count())) {
 144     return NS_ERROR_UNEXPECTED;
 145   }
 146
 147   if (mIsUnicode) {
 148     aResult = mArray->ElementAt(mIndex++);
 149   } else {
 150     CopyUTF8toUTF16(mCArray->ElementAt(mIndex++), aResult);
 151   }
 152
 153   return NS_OK;
 154 }
 155
 156 NS_IMETHODIMP
 157 nsStringEnumerator::GetNext(nsACString& aResult)
 158 {
 159   if (NS_WARN_IF(mIndex >= Count())) {
 160     return NS_ERROR_UNEXPECTED;
 161   }
 162
 163   if (mIsUnicode) {
 164     CopyUTF16toUTF8(mArray->ElementAt(mIndex++), aResult);
 165   } else {
 166     aResult = mCArray->ElementAt(mIndex++);
 167   }
 168
 169   return NS_OK;
 170 }
 171
 172 template<class T>
 173 static inline nsresult
 174 StringEnumeratorTail(T** aResult)
 175 {
 176   if (!*aResult) {
 177     return NS_ERROR_OUT_OF_MEMORY;
 178   }
 179   NS_ADDREF(*aResult);
 180   return NS_OK;
 181 }
 182
 183 //
 184 // constructors
 185 //
 186
 187 nsresult
 188 NS_NewStringEnumerator(nsIStringEnumerator** aResult,
 189                        const nsTArray<nsString>* aArray, nsISupports* aOwner)
 190 {
 191   if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
 192     return NS_ERROR_INVALID_ARG;
 193   }
 194
 195   *aResult = new nsStringEnumerator(aArray, aOwner);
 196   return StringEnumeratorTail(aResult);
 197 }
 198
 199
 200 nsresult
 201 NS_NewUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
 202                            const nsTArray<nsCString>* aArray,
 203                            nsISupports* aOwner)
 204 {
 205   if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
 206     return NS_ERROR_INVALID_ARG;
 207   }
 208
 209   *aResult = new nsStringEnumerator(aArray, aOwner);
 210   return StringEnumeratorTail(aResult);
 211 }
 212
 213 nsresult
 214 NS_NewAdoptingStringEnumerator(nsIStringEnumerator** aResult,
 215                                nsTArray<nsString>* aArray)
 216 {
 217   if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
 218     return NS_ERROR_INVALID_ARG;
 219   }
 220
 221   *aResult = new nsStringEnumerator(aArray, true);
 222   return StringEnumeratorTail(aResult);
 223 }
 224
 225 nsresult
 226 NS_NewAdoptingUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
 227                                    nsTArray<nsCString>* aArray)
 228 {
 229   if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
 230     return NS_ERROR_INVALID_ARG;
 231   }
 232
 233   *aResult = new nsStringEnumerator(aArray, true);
 234   return StringEnumeratorTail(aResult);
 235 }
 236
 237 // const ones internally just forward to the non-const equivalents
 238 nsresult
 239 NS_NewStringEnumerator(nsIStringEnumerator** aResult,
 240                        const nsTArray<nsString>* aArray)
 241 {
 242   if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
 243     return NS_ERROR_INVALID_ARG;
 244   }
 245
 246   *aResult = new nsStringEnumerator(aArray, false);
 247   return StringEnumeratorTail(aResult);
 248 }
 249
 250 nsresult
 251 NS_NewUTF8StringEnumerator(nsIUTF8StringEnumerator** aResult,
 252                            const nsTArray<nsCString>* aArray)
 253 {
 254   if (NS_WARN_IF(!aResult) || NS_WARN_IF(!aArray)) {
 255     return NS_ERROR_INVALID_ARG;
 256   }
 257
 258   *aResult = new nsStringEnumerator(aArray, false);
 259   return StringEnumeratorTail(aResult);
 260 }
 261