Mypal/dom/encoding/TextEncoder.cpp

82 lines
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/dom/EncodingUtils.h"
#include "mozilla/UniquePtrExtensions.h"
#include "nsContentUtils.h"
namespace mozilla {
namespace dom {
void
TextEncoder::Init()
{
// Create an encoder object for utf-8.
mEncoder = EncodingUtils::EncoderForEncoding(NS_LITERAL_CSTRING("UTF-8"));
}
void
TextEncoder::Encode(JSContext* aCx,
JS::Handle<JSObject*> aObj,
const nsAString& aString,
JS::MutableHandle<JSObject*> aRetval,
ErrorResult& aRv)
{
// Run the steps of the encoding algorithm.
int32_t srcLen = aString.Length();
int32_t maxLen;
const char16_t* data = aString.BeginReading();
nsresult rv = mEncoder->GetMaxLength(data, srcLen, &maxLen);
if (NS_FAILED(rv)) {
aRv.Throw(rv);
return;
}
// Need a fallible allocator because the caller may be a content
// and the content can specify the length of the string.
auto buf = MakeUniqueFallible<char[]>(maxLen + 1);
if (!buf) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
int32_t dstLen = maxLen;
rv = mEncoder->Convert(data, &srcLen, buf.get(), &dstLen);
// Now reset the encoding algorithm state to the default values for encoding.
int32_t finishLen = maxLen - dstLen;
rv = mEncoder->Finish(&buf[dstLen], &finishLen);
if (NS_SUCCEEDED(rv)) {
dstLen += finishLen;
}
JSObject* outView = nullptr;
if (NS_SUCCEEDED(rv)) {
buf[dstLen] = '\0';
JSAutoCompartment ac(aCx, aObj);
outView = Uint8Array::Create(aCx, dstLen,
reinterpret_cast<uint8_t*>(buf.get()));
if (!outView) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
if (NS_FAILED(rv)) {
aRv.Throw(rv);
}
aRetval.set(outView);
}
void
TextEncoder::GetEncoding(nsAString& aEncoding)
{
aEncoding.AssignLiteral("utf-8");
}
} // namespace dom
} // namespace mozilla