gecko-dev/dom/encoding/TextEncoder.cpp

70 строки
2.2 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/TextEncoder.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/UniquePtrExtensions.h"
#include "nsReadableUtils.h"
namespace mozilla {
namespace dom {
void TextEncoder::Init() {}
void TextEncoder::Encode(JSContext* aCx, JS::Handle<JSObject*> aObj,
const nsAString& aString,
JS::MutableHandle<JSObject*> aRetval,
ErrorResult& aRv) {
// Given nsTSubstring<char16_t>::kMaxCapacity, it should be
// impossible for the length computation to overflow, but
// let's use checked math in case someone changes something
// in the future.
// Uint8Array::Create takes uint32_t as the length.
CheckedInt<uint32_t> bufLen(aString.Length());
bufLen *= 3; // from the contract for ConvertUTF16toUTF8
if (!bufLen.isValid()) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
auto data = mozilla::MakeUniqueFallible<uint8_t[]>(bufLen.value());
if (!data) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
size_t utf8Len = ConvertUTF16toUTF8(
aString, MakeSpan(reinterpret_cast<char*>(data.get()), bufLen.value()));
MOZ_ASSERT(utf8Len <= bufLen.value());
JSAutoRealm ar(aCx, aObj);
JSObject* outView = Uint8Array::Create(aCx, utf8Len, data.get());
if (!outView) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
aRetval.set(outView);
}
void TextEncoder::EncodeInto(const nsAString& aSrc, const Uint8Array& aDst,
TextEncoderEncodeIntoResult& aResult) {
aDst.ComputeLengthAndData();
size_t read;
size_t written;
Tie(read, written) = ConvertUTF16toUTF8Partial(
aSrc, MakeSpan(reinterpret_cast<char*>(aDst.Data()), aDst.Length()));
aResult.mRead.Construct() = read;
aResult.mWritten.Construct() = written;
}
void TextEncoder::GetEncoding(nsAString& aEncoding) {
aEncoding.AssignLiteral("utf-8");
}
} // namespace dom
} // namespace mozilla