tor-browser

The Tor Browser
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DecompressionStream.cpp (4256B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
      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/DecompressionStream.h"
      8 
      9 #include "BaseAlgorithms.h"
     10 #include "FormatBrotli.h"
     11 #include "FormatZlib.h"
     12 #include "FormatZstd.h"
     13 #include "js/TypeDecls.h"
     14 #include "mozilla/StaticPrefs_dom.h"
     15 #include "mozilla/dom/CompressionStreamBinding.h"
     16 #include "mozilla/dom/DecompressionStreamBinding.h"
     17 #include "mozilla/dom/ReadableStream.h"
     18 #include "mozilla/dom/TextDecoderStream.h"
     19 #include "mozilla/dom/TransformStream.h"
     20 #include "mozilla/dom/UnionTypes.h"
     21 #include "mozilla/dom/WritableStream.h"
     22 
     23 namespace mozilla::dom {
     24 using namespace compression;
     25 
     26 /*
     27 * Constructs either a ZLibDecompressionStreamAlgorithms or a
     28 * Brotli/ZstdDecompressionStreamAlgorithms, based on the CompressionFormat.
     29 */
     30 static Result<already_AddRefed<DecompressionStreamAlgorithms>, nsresult>
     31 CreateDecompressionStreamAlgorithms(CompressionFormat aFormat) {
     32  if (aFormat == CompressionFormat::Brotli) {
     33    RefPtr<DecompressionStreamAlgorithms> brotliAlgos =
     34        MOZ_TRY(BrotliDecompressionStreamAlgorithms::Create());
     35    return brotliAlgos.forget();
     36  }
     37  if (aFormat == CompressionFormat::Zstd) {
     38    RefPtr<DecompressionStreamAlgorithms> zstdAlgos =
     39        MOZ_TRY(ZstdDecompressionStreamAlgorithms::Create());
     40    return zstdAlgos.forget();
     41  }
     42 
     43  RefPtr<DecompressionStreamAlgorithms> zlibAlgos =
     44      MOZ_TRY(ZLibDecompressionStreamAlgorithms::Create(aFormat));
     45  return zlibAlgos.forget();
     46 }
     47 
     48 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DecompressionStream, mGlobal, mStream)
     49 NS_IMPL_CYCLE_COLLECTING_ADDREF(DecompressionStream)
     50 NS_IMPL_CYCLE_COLLECTING_RELEASE(DecompressionStream)
     51 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DecompressionStream)
     52  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
     53  NS_INTERFACE_MAP_ENTRY(nsISupports)
     54 NS_INTERFACE_MAP_END
     55 
     56 DecompressionStream::DecompressionStream(nsISupports* aGlobal,
     57                                         TransformStream& aStream)
     58    : mGlobal(aGlobal), mStream(&aStream) {}
     59 
     60 DecompressionStream::~DecompressionStream() = default;
     61 
     62 JSObject* DecompressionStream::WrapObject(JSContext* aCx,
     63                                          JS::Handle<JSObject*> aGivenProto) {
     64  return DecompressionStream_Binding::Wrap(aCx, this, aGivenProto);
     65 }
     66 
     67 // https://wicg.github.io/compression/#dom-decompressionstream-decompressionstream
     68 already_AddRefed<DecompressionStream> DecompressionStream::Constructor(
     69    const GlobalObject& aGlobal, CompressionFormat aFormat, ErrorResult& aRv) {
     70  if (aFormat == CompressionFormat::Zstd &&
     71      aGlobal.CallerType() != CallerType::System &&
     72      !StaticPrefs::dom_compression_streams_zstd_enabled()) {
     73    aRv.ThrowTypeError(
     74        "'zstd' (value of argument 1) is not a valid value for enumeration "
     75        "CompressionFormat.");
     76    return nullptr;
     77  }
     78 
     79  // Step 1: If format is unsupported in DecompressionStream, then throw a
     80  // TypeError.
     81  // XXX: Skipped as we are using enum for this
     82 
     83  // Step 2 - 4: (Done in {ZLib|Zstd}DecompressionStreamAlgorithms)
     84 
     85  // Step 5: Set this's transform to a new TransformStream.
     86 
     87  // Step 6: Set up this's transform with transformAlgorithm set to
     88  // transformAlgorithm and flushAlgorithm set to flushAlgorithm.
     89 
     90  Result<already_AddRefed<DecompressionStreamAlgorithms>, nsresult> algorithms =
     91      CreateDecompressionStreamAlgorithms(aFormat);
     92  if (algorithms.isErr()) {
     93    aRv.ThrowUnknownError("Not enough memory");
     94    return nullptr;
     95  }
     96 
     97  RefPtr<DecompressionStreamAlgorithms> alg = algorithms.unwrap();
     98  RefPtr<TransformStream> stream =
     99      TransformStream::CreateGeneric(aGlobal, *alg, aRv);
    100  if (aRv.Failed()) {
    101    return nullptr;
    102  }
    103  return do_AddRef(new DecompressionStream(aGlobal.GetAsSupports(), *stream));
    104 }
    105 
    106 already_AddRefed<ReadableStream> DecompressionStream::Readable() const {
    107  return do_AddRef(mStream->Readable());
    108 };
    109 
    110 already_AddRefed<WritableStream> DecompressionStream::Writable() const {
    111  return do_AddRef(mStream->Writable());
    112 };
    113 
    114 }  // namespace mozilla::dom