gecko/dom/encoding/TextEncoder.cpp

137 lines
4.0 KiB
C++

/* 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 "nsContentUtils.h"
#include "nsICharsetConverterManager.h"
#include "nsServiceManagerUtils.h"
namespace mozilla {
namespace dom {
void
TextEncoder::Init(const Optional<nsAString>& aEncoding,
ErrorResult& aRv)
{
// If the constructor is called with no arguments, let label be the "utf-8".
// Otherwise, let label be the value of the encoding argument.
nsAutoString label;
if (!aEncoding.WasPassed()) {
label.AssignLiteral("utf-8");
} else {
label.Assign(aEncoding.Value());
EncodingUtils::TrimSpaceCharacters(label);
}
// Run the steps to get an encoding from Encoding.
if (!EncodingUtils::FindEncodingForLabel(label, mEncoding)) {
// If the steps result in failure,
// throw an "EncodingError" exception and terminate these steps.
aRv.Throw(NS_ERROR_DOM_ENCODING_NOT_SUPPORTED_ERR);
return;
}
// Otherwise, if the Name of the returned encoding is not one of
// "utf-8", "utf-16", or "utf-16be" throw an "EncodingError" exception
// and terminate these steps.
if (PL_strcasecmp(mEncoding, "utf-8") &&
PL_strcasecmp(mEncoding, "utf-16le") &&
PL_strcasecmp(mEncoding, "utf-16be")) {
aRv.Throw(NS_ERROR_DOM_ENCODING_NOT_UTF_ERR);
return;
}
// Create an encoder object for mEncoding.
nsCOMPtr<nsICharsetConverterManager> ccm =
do_GetService(NS_CHARSETCONVERTERMANAGER_CONTRACTID);
if (!ccm) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return;
}
ccm->GetUnicodeEncoder(mEncoding, getter_AddRefs(mEncoder));
if (!mEncoder) {
aRv.Throw(NS_ERROR_UNEXPECTED);
return;
}
}
JSObject*
TextEncoder::Encode(JSContext* aCx,
const nsAString& aString,
const TextEncodeOptions& aOptions,
ErrorResult& aRv)
{
// Run the steps of the encoding algorithm.
int32_t srcLen = aString.Length();
int32_t maxLen;
const PRUnichar* data = PromiseFlatString(aString).get();
nsresult rv = mEncoder->GetMaxLength(data, srcLen, &maxLen);
if (NS_FAILED(rv)) {
aRv.Throw(rv);
return nullptr;
}
// Need a fallible allocator because the caller may be a content
// and the content can specify the length of the string.
static const fallible_t fallible = fallible_t();
nsAutoArrayPtr<char> buf(new (fallible) char[maxLen + 1]);
if (!buf) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
int32_t dstLen = maxLen;
rv = mEncoder->Convert(data, &srcLen, buf, &dstLen);
// If the internal streaming flag is not set, then reset
// the encoding algorithm state to the default values for encoding.
if (!aOptions.stream) {
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';
outView = Uint8Array::Create(aCx, this, dstLen,
reinterpret_cast<uint8_t*>(buf.get()));
}
if (NS_FAILED(rv)) {
aRv.Throw(rv);
}
return outView;
}
void
TextEncoder::GetEncoding(nsAString& aEncoding)
{
// Our utf-16 converter does not comply with the Encoding Standard.
// As a result the utf-16le converter is used for the encoding label
// "utf-16".
// This workaround should not be exposed to the public API and so "utf-16"
// is returned by GetEncoding() if the internal encoding name is "utf-16le".
if (!strcmp(mEncoding, "utf-16le")) {
aEncoding.AssignLiteral("utf-16");
return;
}
aEncoding.AssignASCII(mEncoding);
}
NS_IMPL_CYCLE_COLLECTING_ADDREF(TextEncoder)
NS_IMPL_CYCLE_COLLECTING_RELEASE(TextEncoder)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(TextEncoder)
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_1(TextEncoder, mGlobal)
} // dom
} // mozilla