dom/encoding/TextDecoder.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_textdecoder_h_
   8 #define mozilla_dom_textdecoder_h_
   9
  10 #include "mozilla/dom/NonRefcountedDOMObject.h"
  11 #include "mozilla/dom/TextDecoderBinding.h"
  12 #include "mozilla/dom/TypedArray.h"
  13 #include "mozilla/Encoding.h"
  14 #include "mozilla/ErrorResult.h"
  15 #include "mozilla/UniquePtr.h"
  16
  17 namespace mozilla::dom {
  18
  19 class ArrayBufferViewOrArrayBuffer;
  20
  21 class TextDecoderCommon {
  22  public:
  23   /**
  24    * Decodes incoming byte stream of characters in charset indicated by
  25    * encoding.
  26    *
  27    * The encoding algorithm state is reset if aOptions.mStream is not set.
  28    *
  29    * If the fatal flag is set then a decoding error will throw EncodingError.
  30    * Else the decoder will return a decoded string with replacement
  31    * character(s) for unidentified character(s).
  32    *
  33    * @param      aInput, incoming byte stream of characters to be decoded to
  34    *                    to UTF-16 code points.
  35    * @param      aStream, indicates if streaming or not.
  36    * @param      aOutDecodedString, decoded string of UTF-16 code points.
  37    * @param      aRv, error result.
  38    */
  39   void DecodeNative(mozilla::Span<const uint8_t> aInput, const bool aStream,
  40                     nsAString& aOutDecodedString, ErrorResult& aRv);
  41
  42   /**
  43    * Return the encoding name.
  44    *
  45    * @param aEncoding, current encoding.
  46    */
  47   void GetEncoding(nsAString& aEncoding);
  48
  49   bool Fatal() const { return mFatal; }
  50
  51   bool IgnoreBOM() const { return mIgnoreBOM; }
  52
  53  protected:
  54   mozilla::UniquePtr<mozilla::Decoder> mDecoder;
  55   nsCString mEncoding;
  56   bool mFatal = false;
  57   bool mIgnoreBOM = false;
  58 };
  59
  60 class TextDecoder final : public NonRefcountedDOMObject,
  61                           public TextDecoderCommon {
  62  public:
  63   // The WebIDL constructor.
  64   static UniquePtr<TextDecoder> Constructor(const GlobalObject& aGlobal,
  65                                             const nsAString& aEncoding,
  66                                             const TextDecoderOptions& aOptions,
  67                                             ErrorResult& aRv) {
  68     auto txtDecoder = MakeUnique<TextDecoder>();
  69     txtDecoder->Init(aEncoding, aOptions, aRv);
  70     if (aRv.Failed()) {
  71       return nullptr;
  72     }
  73     return txtDecoder;
  74   }
  75
  76   TextDecoder() { MOZ_COUNT_CTOR(TextDecoder); }
  77
  78   MOZ_COUNTED_DTOR(TextDecoder)
  79
  80   bool WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
  81                   JS::MutableHandle<JSObject*> aReflector) {
  82     return TextDecoder_Binding::Wrap(aCx, this, aGivenProto, aReflector);
  83   }
  84
  85   /**
  86    * Validates provided label and throws an exception if invalid label.
  87    *
  88    * @param aLabel       The encoding label (case insensitive) provided.
  89    * @param aOptions     The TextDecoderOptions to use.
  90    * @return aRv         EncodingError exception else null.
  91    */
  92   void Init(const nsAString& aLabel, const TextDecoderOptions& aOptions,
  93             ErrorResult& aRv);
  94
  95   /**
  96    * Performs initialization with a Gecko-canonical encoding name (as opposed
  97    * to a label.)
  98    *
  99    * @param aEncoding    An Encoding object
 100    * @param aOptions     The TextDecoderOptions to use.
 101    */
 102   void InitWithEncoding(NotNull<const Encoding*> aEncoding,
 103                         const TextDecoderOptions& aOptions);
 104
 105   void Decode(const Optional<ArrayBufferViewOrArrayBuffer>& aBuffer,
 106               const TextDecodeOptions& aOptions, nsAString& aOutDecodedString,
 107               ErrorResult& aRv);
 108
 109  private:
 110 };
 111
 112 }  // namespace mozilla::dom
 113
 114 #endif  // mozilla_dom_textdecoder_h_