tor-browser

The Tor Browser
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TextDecoder.cpp (3968B)

      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
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "mozilla/dom/TextDecoder.h"
      8 
      9 #include <stdint.h>
     10 
     11 #include "mozilla/Encoding.h"
     12 #include "mozilla/dom/BufferSourceBinding.h"
     13 #include "mozilla/dom/UnionTypes.h"
     14 #include "nsContentUtils.h"
     15 
     16 namespace mozilla::dom {
     17 
     18 void TextDecoder::Init(const nsAString& aLabel,
     19                       const TextDecoderOptions& aOptions, ErrorResult& aRv) {
     20  // Let encoding be the result of getting an encoding from label.
     21  // If encoding is failure or replacement, throw a RangeError
     22  // (https://encoding.spec.whatwg.org/#dom-textdecoder).
     23  const Encoding* encoding = Encoding::ForLabelNoReplacement(aLabel);
     24  if (!encoding) {
     25    NS_ConvertUTF16toUTF8 label(aLabel);
     26    label.Trim(" \t\n\f\r");
     27    aRv.ThrowRangeError<MSG_ENCODING_NOT_SUPPORTED>(label);
     28    return;
     29  }
     30  InitWithEncoding(WrapNotNull(encoding), aOptions);
     31 }
     32 
     33 void TextDecoder::InitWithEncoding(NotNull<const Encoding*> aEncoding,
     34                                   const TextDecoderOptions& aOptions) {
     35  aEncoding->Name(mEncoding);
     36  // Store the flags passed via our options dictionary.
     37  mFatal = aOptions.mFatal;
     38  mIgnoreBOM = aOptions.mIgnoreBOM;
     39 
     40  // Create a decoder object for mEncoding.
     41  if (mIgnoreBOM) {
     42    mDecoder = aEncoding->NewDecoderWithoutBOMHandling();
     43  } else {
     44    mDecoder = aEncoding->NewDecoderWithBOMRemoval();
     45  }
     46 }
     47 
     48 void TextDecoderCommon::DecodeNative(Span<const uint8_t> aInput,
     49                                     const bool aStream,
     50                                     nsAString& aOutDecodedString,
     51                                     ErrorResult& aRv) {
     52  aOutDecodedString.Truncate();
     53 
     54  CheckedInt<nsAString::size_type> needed =
     55      mDecoder->MaxUTF16BufferLength(aInput.Length());
     56  if (!needed.isValid()) {
     57    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
     58    return;
     59  }
     60 
     61  auto output = aOutDecodedString.GetMutableData(needed.value(), fallible);
     62  if (!output) {
     63    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
     64    return;
     65  }
     66 
     67  uint32_t result;
     68  size_t read;
     69  size_t written;
     70  if (mFatal) {
     71    std::tie(result, read, written) =
     72        mDecoder->DecodeToUTF16WithoutReplacement(aInput, *output, !aStream);
     73    if (result != kInputEmpty) {
     74      aRv.ThrowTypeError<MSG_DOM_DECODING_FAILED>();
     75      return;
     76    }
     77  } else {
     78    std::tie(result, read, written, std::ignore) =
     79        mDecoder->DecodeToUTF16(aInput, *output, !aStream);
     80  }
     81  MOZ_ASSERT(result == kInputEmpty);
     82  MOZ_ASSERT(read == aInput.Length());
     83  MOZ_ASSERT(written <= aOutDecodedString.Length());
     84 
     85  if (!aOutDecodedString.SetLength(written, fallible)) {
     86    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
     87    return;
     88  }
     89 
     90  // If the internal streaming flag of the decoder object is not set,
     91  // then reset the encoding algorithm state to the default values
     92  if (!aStream) {
     93    if (mIgnoreBOM) {
     94      mDecoder->Encoding()->NewDecoderWithoutBOMHandlingInto(*mDecoder);
     95    } else {
     96      mDecoder->Encoding()->NewDecoderWithBOMRemovalInto(*mDecoder);
     97    }
     98  }
     99 }
    100 
    101 void TextDecoder::Decode(const Optional<BufferSource>& aBuffer,
    102                         const TextDecodeOptions& aOptions,
    103                         nsAString& aOutDecodedString, ErrorResult& aRv) {
    104  if (!aBuffer.WasPassed()) {
    105    DecodeNative(nullptr, aOptions.mStream, aOutDecodedString, aRv);
    106    return;
    107  }
    108 
    109  ProcessTypedArrays(aBuffer.Value(), [&](const Span<uint8_t>& aData,
    110                                          JS::AutoCheckCannotGC&&) {
    111    DecodeNative(aData, aOptions.mStream, aOutDecodedString, aRv);
    112  });
    113 }
    114 
    115 void TextDecoderCommon::GetEncoding(nsAString& aEncoding) {
    116  CopyASCIItoUTF16(mEncoding, aEncoding);
    117  nsContentUtils::ASCIIToLower(aEncoding);
    118 }
    119 
    120 }  // namespace mozilla::dom