dom/encoding/TextDecoder.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   3  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef mozilla_dom_textdecoder_h_
   6 #define mozilla_dom_textdecoder_h_
   7
   8 #include "mozilla/dom/NonRefcountedDOMObject.h"
   9 #include "mozilla/dom/TextDecoderBinding.h"
  10 #include "mozilla/dom/TypedArray.h"
  11 #include "nsIUnicodeDecoder.h"
  12
  13 namespace mozilla {
  14
  15 class ErrorResult;
  16
  17 namespace dom {
  18
  19 class TextDecoder MOZ_FINAL
  20   : public NonRefcountedDOMObject
  21 {
  22 public:
  23   // The WebIDL constructor.
  24   static TextDecoder*
  25   Constructor(const GlobalObject& aGlobal,
  26               const nsAString& aEncoding,
  27               const TextDecoderOptions& aOptions,
  28               ErrorResult& aRv)
  29   {
  30     nsAutoPtr<TextDecoder> txtDecoder(new TextDecoder());
  31     txtDecoder->Init(aEncoding, aOptions.mFatal, aRv);
  32     if (aRv.Failed()) {
  33       return nullptr;
  34     }
  35     return txtDecoder.forget();
  36   }
  37
  38   TextDecoder()
  39     : mFatal(false)
  40   {
  41     MOZ_COUNT_CTOR(TextDecoder);
  42   }
  43
  44   ~TextDecoder()
  45   {
  46     MOZ_COUNT_DTOR(TextDecoder);
  47   }
  48
  49   JSObject* WrapObject(JSContext* aCx, bool* aTookOwnership)
  50   {
  51     return TextDecoderBinding::Wrap(aCx, this, aTookOwnership);
  52   }
  53
  54   /**
  55    * Validates provided label and throws an exception if invalid label.
  56    *
  57    * @param aLabel       The encoding label (case insensitive) provided.
  58    * @param aFatal       indicates whether to throw an 'EncodingError'
  59    *                     exception or not when decoding.
  60    * @return aRv         EncodingError exception else null.
  61    */
  62   void Init(const nsAString& aLabel, const bool aFatal, ErrorResult& aRv);
  63
  64   /**
  65    * Performs initialization with a Gecko-canonical encoding name (as opposed
  66    * to a label.)
  67    *
  68    * @param aEncoding    A Gecko-canonical encoding name
  69    * @param aFatal       indicates whether to throw an 'EncodingError'
  70    *                     exception or not when decoding.
  71    */
  72   void InitWithEncoding(const nsACString& aEncoding, const bool aFatal);
  73
  74   /**
  75    * Return the encoding name.
  76    *
  77    * @param aEncoding, current encoding.
  78    */
  79   void GetEncoding(nsAString& aEncoding);
  80
  81   /**
  82    * Decodes incoming byte stream of characters in charset indicated by
  83    * encoding.
  84    *
  85    * The encoding algorithm state is reset if aOptions.mStream is not set.
  86    *
  87    * If the fatal flag is set then a decoding error will throw EncodingError.
  88    * Else the decoder will return a decoded string with replacement
  89    * character(s) for unidentified character(s).
  90    *
  91    * @param      aView, incoming byte stream of characters to be decoded to
  92    *                    to UTF-16 code points.
  93    * @param      aOptions, indicates if streaming or not.
  94    * @param      aOutDecodedString, decoded string of UTF-16 code points.
  95    * @param      aRv, error result.
  96    */
  97   void Decode(const char* aInput, const int32_t aLength,
  98               const bool aStream, nsAString& aOutDecodedString,
  99               ErrorResult& aRv);
 100
 101   void Decode(nsAString& aOutDecodedString,
 102               ErrorResult& aRv) {
 103     Decode(nullptr, 0, false, aOutDecodedString, aRv);
 104   }
 105
 106   void Decode(const ArrayBufferView& aView,
 107               const TextDecodeOptions& aOptions,
 108               nsAString& aOutDecodedString,
 109               ErrorResult& aRv) {
 110     aView.ComputeLengthAndData();
 111     Decode(reinterpret_cast<char*>(aView.Data()), aView.Length(),
 112            aOptions.mStream, aOutDecodedString, aRv);
 113   }
 114
 115 private:
 116   nsCString mEncoding;
 117   nsCOMPtr<nsIUnicodeDecoder> mDecoder;
 118   bool mFatal;
 119 };
 120
 121 } // dom
 122 } // mozilla
 123
 124 #endif // mozilla_dom_textdecoder_h_