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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/dom/TextEncoderStream.h"
#include "js/ArrayBuffer.h"
#include "js/experimental/TypedData.h"
#include "nsIGlobalObject.h"
#include "mozilla/Encoding.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/TextEncoderStreamBinding.h"
#include "mozilla/dom/TransformerCallbackHelpers.h"
#include "mozilla/dom/TransformStream.h"
namespace mozilla::dom {
NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(TextEncoderStream, mGlobal, mStream)
NS_IMPL_CYCLE_COLLECTING_ADDREF(TextEncoderStream)
NS_IMPL_CYCLE_COLLECTING_RELEASE(TextEncoderStream)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(TextEncoderStream)
NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
TextEncoderStream::TextEncoderStream(nsISupports* aGlobal,
TransformStream& aStream)
: mGlobal(aGlobal), mStream(&aStream) {
// See the comment in EncodeNative() about why this uses a decoder instead of
// `UTF_8_ENCODING->NewEncoder()`.
// XXX: We have to consciously choose 16LE/BE because we ultimately have to read
// char16_t* as uint8_t*. See the same comment.
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
mDecoder = UTF_16LE_ENCODING->NewDecoder();
#else
mDecoder = UTF_16BE_ENCODING->NewDecoder();
#endif
}
TextEncoderStream::~TextEncoderStream() = default;
JSObject* TextEncoderStream::WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) {
return TextEncoderStream_Binding::Wrap(aCx, this, aGivenProto);
}
// Note that the most of the encoding algorithm is implemented in
// mozilla::Decoder (see the comment in EncodeNative()), and this is mainly
// about calling it properly.
static void EncodeNative(JSContext* aCx, mozilla::Decoder* aDecoder,
Span<const char16_t> aInput, const bool aFlush,
JS::MutableHandle<JSObject*> aOutputArrayBufferView,
ErrorResult& aRv) {
// XXX: Adjust the length since Decoder always accepts uint8_t (whereas
// Encoder also accepts char16_t, see below).
if (aInput.Length() > SIZE_MAX / 2) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
size_t lengthU8 = aInput.Length() * 2;
CheckedInt<nsAString::size_type> needed =
aDecoder->MaxUTF8BufferLength(lengthU8);
if (!needed.isValid()) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
UniquePtr<uint8_t> buffer(
static_cast<uint8_t*>(JS_malloc(aCx, needed.value())));
if (!buffer) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
mozilla::Span<uint8_t> input((uint8_t*)aInput.data(), lengthU8);
mozilla::Span<uint8_t> output(buffer, needed.value());
// This originally wanted to use mozilla::Encoder::Encode() that accepts
// char16_t*, but it lacks the pending-high-surrogate feature to properly
// implement
// https://encoding.spec.whatwg.org/#convert-code-unit-to-scalar-value.
// See also https://github.com/hsivonen/encoding_rs/issues/82 about the
// reasoning.
// XXX: The code is more verbose here since we need to convert to
// uint8_t* which is the only type mozilla::Decoder accepts.
uint32_t result;
size_t read;
size_t written;
std::tie(result, read, written, std::ignore) =
aDecoder->DecodeToUTF8(input, output, aFlush);
MOZ_ASSERT(result == kInputEmpty);
MOZ_ASSERT(read == lengthU8);
MOZ_ASSERT(written <= needed.value());
// https://encoding.spec.whatwg.org/#encode-and-enqueue-a-chunk
// Step 4.2.2.1. Let chunk be a Uint8Array object wrapping an ArrayBuffer
// containing output.
JS::Rooted<JSObject*> arrayBuffer(
aCx, JS::NewArrayBufferWithContents(aCx, written, buffer.release()));
if (!arrayBuffer.get()) {
JS_ClearPendingException(aCx);
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
aOutputArrayBufferView.set(JS_NewUint8ArrayWithBuffer(
aCx, arrayBuffer, 0, static_cast<int64_t>(written)));
if (!aOutputArrayBufferView.get()) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
class TextEncoderStreamAlgorithms : public TransformerAlgorithmsWrapper {
NS_DECL_ISUPPORTS_INHERITED
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(TextEncoderStreamAlgorithms,
TransformerAlgorithmsBase)
void SetEncoderStream(TextEncoderStream& aStream) {
mEncoderStream = &aStream;
}
// The common part of encode-and-enqueue and encode-and-flush.
// https://encoding.spec.whatwg.org/#decode-and-enqueue-a-chunk
MOZ_CAN_RUN_SCRIPT void EncodeAndEnqueue(
JSContext* aCx, const nsAString& aInput,
TransformStreamDefaultController& aController, bool aFlush,
ErrorResult& aRv) {
JS::Rooted<JSObject*> outView(aCx);
// Passing a Decoder for a reason, see the comments in the method.
EncodeNative(aCx, mEncoderStream->Decoder(), aInput, aFlush, &outView, aRv);
if (JS_GetTypedArrayLength(outView) > 0) {
// Step 4.2.2.2. Enqueue chunk into encoder’s transform.
JS::Rooted<JS::Value> value(aCx, JS::ObjectValue(*outView));
aController.Enqueue(aCx, value, aRv);
}
}
// https://encoding.spec.whatwg.org/#dom-textencoderstream
MOZ_CAN_RUN_SCRIPT void TransformCallbackImpl(
JS::Handle<JS::Value> aChunk,
TransformStreamDefaultController& aController,
ErrorResult& aRv) override {
// Step 2. Let transformAlgorithm be an algorithm which takes a chunk
// argument and runs the encode and enqueue a chunk algorithm with this and
// chunk.
AutoJSAPI jsapi;
if (!jsapi.Init(aController.GetParentObject())) {
aRv.ThrowUnknownError("Internal error");
return;
}
JSContext* cx = jsapi.cx();
// https://encoding.spec.whatwg.org/#encode-and-enqueue-a-chunk
// Step 1. Let input be the result of converting chunk to a DOMString.
// Step 2. Convert input to an I/O queue of code units.
nsString str;
if (!ConvertJSValueToString(cx, aChunk, eStringify, eStringify, str)) {
aRv.MightThrowJSException();
aRv.StealExceptionFromJSContext(cx);
return;
}
EncodeAndEnqueue(cx, str, aController, false, aRv);
}
// https://encoding.spec.whatwg.org/#dom-textencoderstream
MOZ_CAN_RUN_SCRIPT void FlushCallbackImpl(
TransformStreamDefaultController& aController,
ErrorResult& aRv) override {
// Step 3. Let flushAlgorithm be an algorithm which runs the encode and
// flush algorithm with this.
AutoJSAPI jsapi;
if (!jsapi.Init(aController.GetParentObject())) {
aRv.ThrowUnknownError("Internal error");
return;
}
JSContext* cx = jsapi.cx();
// The spec manually manages pending high surrogate here, but let's call the
// encoder as it's managed there.
EncodeAndEnqueue(cx, u""_ns, aController, true, aRv);
}
private:
~TextEncoderStreamAlgorithms() override = default;
RefPtr<TextEncoderStream> mEncoderStream;
};
NS_IMPL_CYCLE_COLLECTION_INHERITED(TextEncoderStreamAlgorithms,
TransformerAlgorithmsBase, mEncoderStream)
NS_IMPL_ADDREF_INHERITED(TextEncoderStreamAlgorithms, TransformerAlgorithmsBase)
NS_IMPL_RELEASE_INHERITED(TextEncoderStreamAlgorithms,
TransformerAlgorithmsBase)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(TextEncoderStreamAlgorithms)
NS_INTERFACE_MAP_END_INHERITING(TransformerAlgorithmsBase)
// https://encoding.spec.whatwg.org/#dom-textencoderstream
already_AddRefed<TextEncoderStream> TextEncoderStream::Constructor(
const GlobalObject& aGlobal, ErrorResult& aRv) {
// Step 1. Set this’s encoder to an instance of the UTF-8 encoder.
// Step 2-3
auto algorithms = MakeRefPtr<TextEncoderStreamAlgorithms>();
// Step 4-5
RefPtr<TransformStream> transformStream =
TransformStream::CreateGeneric(aGlobal, *algorithms, aRv);
if (aRv.Failed()) {
return nullptr;
}
// Step 6. Set this’s transform to transformStream.
// (Done in the constructor)
auto encoderStream =
MakeRefPtr<TextEncoderStream>(aGlobal.GetAsSupports(), *transformStream);
algorithms->SetEncoderStream(*encoderStream);
return encoderStream.forget();
}
ReadableStream* TextEncoderStream::Readable() const {
return mStream->Readable();
}
WritableStream* TextEncoderStream::Writable() const {
return mStream->Writable();
}
void TextEncoderStream::GetEncoding(nsCString& aRetVal) const {
aRetVal.AssignLiteral("utf-8");
}
} // namespace mozilla::dom
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