summaryrefslogtreecommitdiffstats
path: root/dom/json/nsJSON.cpp
diff options
context:
space:
mode:
authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /dom/json/nsJSON.cpp
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
downloadUXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.gz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.lz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.xz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.zip
Add m-esr52 at 52.6.0
Diffstat (limited to 'dom/json/nsJSON.cpp')
-rw-r--r--dom/json/nsJSON.cpp656
1 files changed, 656 insertions, 0 deletions
diff --git a/dom/json/nsJSON.cpp b/dom/json/nsJSON.cpp
new file mode 100644
index 000000000..36766e8fe
--- /dev/null
+++ b/dom/json/nsJSON.cpp
@@ -0,0 +1,656 @@
+/* -*- 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 "jsapi.h"
+#include "js/CharacterEncoding.h"
+#include "nsJSON.h"
+#include "nsIXPConnect.h"
+#include "nsIXPCScriptable.h"
+#include "nsStreamUtils.h"
+#include "nsIInputStream.h"
+#include "nsStringStream.h"
+#include "mozilla/dom/EncodingUtils.h"
+#include "nsIUnicodeEncoder.h"
+#include "nsIUnicodeDecoder.h"
+#include "nsXPCOMStrings.h"
+#include "nsNetUtil.h"
+#include "nsIURI.h"
+#include "nsComponentManagerUtils.h"
+#include "nsContentUtils.h"
+#include "nsIScriptError.h"
+#include "nsCRTGlue.h"
+#include "nsIScriptSecurityManager.h"
+#include "nsNullPrincipal.h"
+#include "mozilla/Maybe.h"
+#include <algorithm>
+
+using mozilla::dom::EncodingUtils;
+
+#define JSON_STREAM_BUFSIZE 4096
+
+NS_INTERFACE_MAP_BEGIN(nsJSON)
+ NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIJSON)
+ NS_INTERFACE_MAP_ENTRY(nsIJSON)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_ADDREF(nsJSON)
+NS_IMPL_RELEASE(nsJSON)
+
+nsJSON::nsJSON()
+{
+}
+
+nsJSON::~nsJSON()
+{
+}
+
+enum DeprecationWarning { EncodeWarning, DecodeWarning };
+
+static nsresult
+WarnDeprecatedMethod(DeprecationWarning warning)
+{
+ return nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+ NS_LITERAL_CSTRING("DOM Core"), nullptr,
+ nsContentUtils::eDOM_PROPERTIES,
+ warning == EncodeWarning
+ ? "nsIJSONEncodeDeprecatedWarning"
+ : "nsIJSONDecodeDeprecatedWarning");
+}
+
+NS_IMETHODIMP
+nsJSON::Encode(JS::Handle<JS::Value> aValue, JSContext* cx, uint8_t aArgc,
+ nsAString &aJSON)
+{
+ // This function should only be called from JS.
+ nsresult rv = WarnDeprecatedMethod(EncodeWarning);
+ if (NS_FAILED(rv))
+ return rv;
+
+ if (aArgc == 0) {
+ aJSON.SetIsVoid(true);
+ return NS_OK;
+ }
+
+ nsJSONWriter writer;
+ rv = EncodeInternal(cx, aValue, &writer);
+
+ // FIXME: bug 408838. Get exception types sorted out
+ if (NS_SUCCEEDED(rv) || rv == NS_ERROR_INVALID_ARG) {
+ rv = NS_OK;
+ // if we didn't consume anything, it's not JSON, so return null
+ if (!writer.DidWrite()) {
+ aJSON.SetIsVoid(true);
+ } else {
+ writer.FlushBuffer();
+ aJSON.Append(writer.mOutputString);
+ }
+ }
+
+ return rv;
+}
+
+static const char UTF8BOM[] = "\xEF\xBB\xBF";
+static const char UTF16LEBOM[] = "\xFF\xFE";
+static const char UTF16BEBOM[] = "\xFE\xFF";
+
+static nsresult CheckCharset(const char* aCharset)
+{
+ // Check that the charset is permissible
+ if (!(strcmp(aCharset, "UTF-8") == 0 ||
+ strcmp(aCharset, "UTF-16LE") == 0 ||
+ strcmp(aCharset, "UTF-16BE") == 0)) {
+ return NS_ERROR_INVALID_ARG;
+ }
+
+ return NS_OK;
+}
+
+NS_IMETHODIMP
+nsJSON::EncodeToStream(nsIOutputStream *aStream,
+ const char* aCharset,
+ const bool aWriteBOM,
+ JS::Handle<JS::Value> val,
+ JSContext* cx,
+ uint8_t aArgc)
+{
+ // This function should only be called from JS.
+ NS_ENSURE_ARG(aStream);
+ nsresult rv;
+
+ rv = CheckCharset(aCharset);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ // Check to see if we have a buffered stream
+ nsCOMPtr<nsIOutputStream> bufferedStream;
+ // FIXME: bug 408514.
+ // NS_OutputStreamIsBuffered(aStream) asserts on file streams...
+ //if (!NS_OutputStreamIsBuffered(aStream)) {
+ rv = NS_NewBufferedOutputStream(getter_AddRefs(bufferedStream),
+ aStream, 4096);
+ NS_ENSURE_SUCCESS(rv, rv);
+ // aStream = bufferedStream;
+ //}
+
+ uint32_t ignored;
+ if (aWriteBOM) {
+ if (strcmp(aCharset, "UTF-8") == 0)
+ rv = aStream->Write(UTF8BOM, 3, &ignored);
+ else if (strcmp(aCharset, "UTF-16LE") == 0)
+ rv = aStream->Write(UTF16LEBOM, 2, &ignored);
+ else if (strcmp(aCharset, "UTF-16BE") == 0)
+ rv = aStream->Write(UTF16BEBOM, 2, &ignored);
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+
+ nsJSONWriter writer(bufferedStream);
+ rv = writer.SetCharset(aCharset);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ if (aArgc == 0) {
+ return NS_OK;
+ }
+
+ rv = EncodeInternal(cx, val, &writer);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ rv = bufferedStream->Flush();
+
+ return rv;
+}
+
+static bool
+WriteCallback(const char16_t *buf, uint32_t len, void *data)
+{
+ nsJSONWriter *writer = static_cast<nsJSONWriter*>(data);
+ nsresult rv = writer->Write((const char16_t*)buf, (uint32_t)len);
+ if (NS_FAILED(rv))
+ return false;
+
+ return true;
+}
+
+NS_IMETHODIMP
+nsJSON::EncodeFromJSVal(JS::Value *value, JSContext *cx, nsAString &result)
+{
+ result.Truncate();
+
+ mozilla::Maybe<JSAutoCompartment> ac;
+ if (value->isObject()) {
+ JS::Rooted<JSObject*> obj(cx, &value->toObject());
+ ac.emplace(cx, obj);
+ }
+
+ nsJSONWriter writer;
+ JS::Rooted<JS::Value> vp(cx, *value);
+ if (!JS_Stringify(cx, &vp, nullptr, JS::NullHandleValue, WriteCallback, &writer)) {
+ return NS_ERROR_XPC_BAD_CONVERT_JS;
+ }
+ *value = vp;
+
+ NS_ENSURE_TRUE(writer.DidWrite(), NS_ERROR_UNEXPECTED);
+ writer.FlushBuffer();
+ result.Assign(writer.mOutputString);
+ return NS_OK;
+}
+
+nsresult
+nsJSON::EncodeInternal(JSContext* cx, const JS::Value& aValue,
+ nsJSONWriter* writer)
+{
+ // Backward compatibility:
+ // nsIJSON does not allow to serialize anything other than objects
+ if (!aValue.isObject()) {
+ return NS_ERROR_INVALID_ARG;
+ }
+ JS::Rooted<JSObject*> obj(cx, &aValue.toObject());
+
+ /* Backward compatibility:
+ * Manually call toJSON if implemented by the object and check that
+ * the result is still an object
+ * Note: It is perfectly fine to not implement toJSON, so it is
+ * perfectly fine for GetMethod to fail
+ */
+ JS::Rooted<JS::Value> val(cx, aValue);
+ JS::Rooted<JS::Value> toJSON(cx);
+ if (JS_GetProperty(cx, obj, "toJSON", &toJSON) &&
+ toJSON.isObject() && JS::IsCallable(&toJSON.toObject())) {
+ // If toJSON is implemented, it must not throw
+ if (!JS_CallFunctionValue(cx, obj, toJSON, JS::HandleValueArray::empty(), &val)) {
+ if (JS_IsExceptionPending(cx))
+ // passing NS_OK will throw the pending exception
+ return NS_OK;
+
+ // No exception, but still failed
+ return NS_ERROR_FAILURE;
+ }
+
+ // Backward compatibility:
+ // nsIJSON does not allow to serialize anything other than objects
+ if (val.isPrimitive())
+ return NS_ERROR_INVALID_ARG;
+ }
+ // GetMethod may have thrown
+ else if (JS_IsExceptionPending(cx))
+ // passing NS_OK will throw the pending exception
+ return NS_OK;
+
+ // Backward compatibility:
+ // function shall not pass, just "plain" objects and arrays
+ JSType type = JS_TypeOfValue(cx, val);
+ if (type == JSTYPE_FUNCTION)
+ return NS_ERROR_INVALID_ARG;
+
+ // We're good now; try to stringify
+ if (!JS_Stringify(cx, &val, nullptr, JS::NullHandleValue, WriteCallback, writer))
+ return NS_ERROR_FAILURE;
+
+ return NS_OK;
+}
+
+
+nsJSONWriter::nsJSONWriter() : mStream(nullptr),
+ mBuffer(nullptr),
+ mBufferCount(0),
+ mDidWrite(false),
+ mEncoder(nullptr)
+{
+}
+
+nsJSONWriter::nsJSONWriter(nsIOutputStream *aStream) : mStream(aStream),
+ mBuffer(nullptr),
+ mBufferCount(0),
+ mDidWrite(false),
+ mEncoder(nullptr)
+{
+}
+
+nsJSONWriter::~nsJSONWriter()
+{
+ delete [] mBuffer;
+}
+
+nsresult
+nsJSONWriter::SetCharset(const char* aCharset)
+{
+ nsresult rv = NS_OK;
+ if (mStream) {
+ mEncoder = EncodingUtils::EncoderForEncoding(aCharset);
+ rv = mEncoder->SetOutputErrorBehavior(nsIUnicodeEncoder::kOnError_Signal,
+ nullptr, '\0');
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+
+ return rv;
+}
+
+nsresult
+nsJSONWriter::Write(const char16_t *aBuffer, uint32_t aLength)
+{
+ if (mStream) {
+ return WriteToStream(mStream, mEncoder, aBuffer, aLength);
+ }
+
+ if (!mDidWrite) {
+ mBuffer = new char16_t[JSON_STREAM_BUFSIZE];
+ mDidWrite = true;
+ }
+
+ if (JSON_STREAM_BUFSIZE <= aLength + mBufferCount) {
+ mOutputString.Append(mBuffer, mBufferCount);
+ mBufferCount = 0;
+ }
+
+ if (JSON_STREAM_BUFSIZE <= aLength) {
+ // we know mBufferCount is 0 because we know we hit the if above
+ mOutputString.Append(aBuffer, aLength);
+ } else {
+ memcpy(&mBuffer[mBufferCount], aBuffer, aLength * sizeof(char16_t));
+ mBufferCount += aLength;
+ }
+
+ return NS_OK;
+}
+
+bool nsJSONWriter::DidWrite()
+{
+ return mDidWrite;
+}
+
+void
+nsJSONWriter::FlushBuffer()
+{
+ mOutputString.Append(mBuffer, mBufferCount);
+}
+
+nsresult
+nsJSONWriter::WriteToStream(nsIOutputStream *aStream,
+ nsIUnicodeEncoder *encoder,
+ const char16_t *aBuffer,
+ uint32_t aLength)
+{
+ nsresult rv;
+ int32_t srcLength = aLength;
+ uint32_t bytesWritten;
+
+ // The bytes written to the stream might differ from the char16_t size
+ int32_t aDestLength;
+ rv = encoder->GetMaxLength(aBuffer, srcLength, &aDestLength);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ // create the buffer we need
+ char* destBuf = (char *) moz_xmalloc(aDestLength);
+ if (!destBuf)
+ return NS_ERROR_OUT_OF_MEMORY;
+
+ rv = encoder->Convert(aBuffer, &srcLength, destBuf, &aDestLength);
+ if (NS_SUCCEEDED(rv))
+ rv = aStream->Write(destBuf, aDestLength, &bytesWritten);
+
+ free(destBuf);
+ mDidWrite = true;
+
+ return rv;
+}
+
+NS_IMETHODIMP
+nsJSON::Decode(const nsAString& json, JSContext* cx,
+ JS::MutableHandle<JS::Value> aRetval)
+{
+ nsresult rv = WarnDeprecatedMethod(DecodeWarning);
+ if (NS_FAILED(rv))
+ return rv;
+
+ const char16_t *data;
+ uint32_t len = NS_StringGetData(json, &data);
+ nsCOMPtr<nsIInputStream> stream;
+ rv = NS_NewByteInputStream(getter_AddRefs(stream),
+ reinterpret_cast<const char*>(data),
+ len * sizeof(char16_t),
+ NS_ASSIGNMENT_DEPEND);
+ NS_ENSURE_SUCCESS(rv, rv);
+ return DecodeInternal(cx, stream, len, false, aRetval);
+}
+
+NS_IMETHODIMP
+nsJSON::DecodeFromStream(nsIInputStream *aStream, int32_t aContentLength,
+ JSContext* cx, JS::MutableHandle<JS::Value> aRetval)
+{
+ return DecodeInternal(cx, aStream, aContentLength, true, aRetval);
+}
+
+NS_IMETHODIMP
+nsJSON::DecodeToJSVal(const nsAString &str, JSContext *cx,
+ JS::MutableHandle<JS::Value> result)
+{
+ if (!JS_ParseJSON(cx, static_cast<const char16_t*>(PromiseFlatString(str).get()),
+ str.Length(), result)) {
+ return NS_ERROR_UNEXPECTED;
+ }
+ return NS_OK;
+}
+
+nsresult
+nsJSON::DecodeInternal(JSContext* cx,
+ nsIInputStream *aStream,
+ int32_t aContentLength,
+ bool aNeedsConverter,
+ JS::MutableHandle<JS::Value> aRetval)
+{
+ // Consume the stream
+ nsCOMPtr<nsIChannel> jsonChannel;
+ if (!mURI) {
+ NS_NewURI(getter_AddRefs(mURI), NS_LITERAL_CSTRING("about:blank"), 0, 0 );
+ if (!mURI)
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+
+ nsresult rv;
+ nsCOMPtr<nsIPrincipal> nullPrincipal = nsNullPrincipal::Create();
+
+ // The ::Decode function is deprecated [Bug 675797] and the following
+ // channel is never openend, so it does not matter what securityFlags
+ // we pass to NS_NewInputStreamChannel here.
+ rv = NS_NewInputStreamChannel(getter_AddRefs(jsonChannel),
+ mURI,
+ aStream,
+ nullPrincipal,
+ nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_IS_BLOCKED,
+ nsIContentPolicy::TYPE_OTHER,
+ NS_LITERAL_CSTRING("application/json"));
+
+ if (!jsonChannel || NS_FAILED(rv))
+ return NS_ERROR_FAILURE;
+
+ RefPtr<nsJSONListener> jsonListener =
+ new nsJSONListener(cx, aRetval.address(), aNeedsConverter);
+
+ //XXX this stream pattern should be consolidated in netwerk
+ rv = jsonListener->OnStartRequest(jsonChannel, nullptr);
+ if (NS_FAILED(rv)) {
+ jsonChannel->Cancel(rv);
+ return rv;
+ }
+
+ nsresult status;
+ jsonChannel->GetStatus(&status);
+ uint64_t offset = 0;
+ while (NS_SUCCEEDED(status)) {
+ uint64_t available;
+ rv = aStream->Available(&available);
+ if (rv == NS_BASE_STREAM_CLOSED) {
+ rv = NS_OK;
+ break;
+ }
+ if (NS_FAILED(rv)) {
+ jsonChannel->Cancel(rv);
+ break;
+ }
+ if (!available)
+ break; // blocking input stream has none available when done
+
+ if (available > UINT32_MAX)
+ available = UINT32_MAX;
+
+ rv = jsonListener->OnDataAvailable(jsonChannel, nullptr,
+ aStream,
+ offset,
+ (uint32_t)available);
+ if (NS_FAILED(rv)) {
+ jsonChannel->Cancel(rv);
+ break;
+ }
+
+ offset += available;
+ jsonChannel->GetStatus(&status);
+ }
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ rv = jsonListener->OnStopRequest(jsonChannel, nullptr, status);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ return NS_OK;
+}
+
+nsresult
+NS_NewJSON(nsISupports* aOuter, REFNSIID aIID, void** aResult)
+{
+ nsJSON* json = new nsJSON();
+ NS_ADDREF(json);
+ *aResult = json;
+
+ return NS_OK;
+}
+
+nsJSONListener::nsJSONListener(JSContext *cx, JS::Value *rootVal,
+ bool needsConverter)
+ : mNeedsConverter(needsConverter),
+ mCx(cx),
+ mRootVal(rootVal)
+{
+}
+
+nsJSONListener::~nsJSONListener()
+{
+}
+
+NS_INTERFACE_MAP_BEGIN(nsJSONListener)
+ NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsJSONListener)
+ NS_INTERFACE_MAP_ENTRY(nsIRequestObserver)
+ NS_INTERFACE_MAP_ENTRY(nsIStreamListener)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_ADDREF(nsJSONListener)
+NS_IMPL_RELEASE(nsJSONListener)
+
+NS_IMETHODIMP
+nsJSONListener::OnStartRequest(nsIRequest *aRequest, nsISupports *aContext)
+{
+ mSniffBuffer.Truncate();
+ mDecoder = nullptr;
+
+ return NS_OK;
+}
+
+NS_IMETHODIMP
+nsJSONListener::OnStopRequest(nsIRequest *aRequest, nsISupports *aContext,
+ nsresult aStatusCode)
+{
+ nsresult rv;
+
+ // This can happen with short UTF-8 messages (<4 bytes)
+ if (!mSniffBuffer.IsEmpty()) {
+ // Just consume mSniffBuffer
+ rv = ProcessBytes(nullptr, 0);
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+
+ JS::Rooted<JS::Value> reviver(mCx, JS::NullValue()), value(mCx);
+
+ JS::ConstTwoByteChars chars(reinterpret_cast<const char16_t*>(mBufferedChars.Elements()),
+ mBufferedChars.Length());
+ bool ok = JS_ParseJSONWithReviver(mCx, chars.begin().get(),
+ uint32_t(mBufferedChars.Length()),
+ reviver, &value);
+
+ *mRootVal = value;
+ mBufferedChars.TruncateLength(0);
+ return ok ? NS_OK : NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsJSONListener::OnDataAvailable(nsIRequest *aRequest, nsISupports *aContext,
+ nsIInputStream *aStream,
+ uint64_t aOffset, uint32_t aLength)
+{
+ nsresult rv = NS_OK;
+
+ if (mNeedsConverter && mSniffBuffer.Length() < 4) {
+ uint32_t readCount = (aLength < 4) ? aLength : 4;
+ rv = NS_ConsumeStream(aStream, readCount, mSniffBuffer);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ if (mSniffBuffer.Length() < 4)
+ return NS_OK;
+ }
+
+ char buffer[JSON_STREAM_BUFSIZE];
+ unsigned long bytesRemaining = aLength - mSniffBuffer.Length();
+ while (bytesRemaining) {
+ unsigned int bytesRead;
+ rv = aStream->Read(buffer,
+ std::min((unsigned long)sizeof(buffer), bytesRemaining),
+ &bytesRead);
+ NS_ENSURE_SUCCESS(rv, rv);
+ rv = ProcessBytes(buffer, bytesRead);
+ NS_ENSURE_SUCCESS(rv, rv);
+ bytesRemaining -= bytesRead;
+ }
+
+ return rv;
+}
+
+nsresult
+nsJSONListener::ProcessBytes(const char* aBuffer, uint32_t aByteLength)
+{
+ nsresult rv;
+ // Check for BOM, or sniff charset
+ nsAutoCString charset;
+ if (mNeedsConverter && !mDecoder) {
+ if (!nsContentUtils::CheckForBOM((const unsigned char*) mSniffBuffer.get(),
+ mSniffBuffer.Length(), charset)) {
+ // OK, found no BOM, sniff the first character to see what this is
+ // See section 3 of RFC4627 for details on why this works.
+ const char *buffer = mSniffBuffer.get();
+ if (mSniffBuffer.Length() >= 4) {
+ if (buffer[0] == 0x00 && buffer[1] != 0x00 &&
+ buffer[2] == 0x00 && buffer[3] != 0x00) {
+ charset = "UTF-16BE";
+ } else if (buffer[0] != 0x00 && buffer[1] == 0x00 &&
+ buffer[2] != 0x00 && buffer[3] == 0x00) {
+ charset = "UTF-16LE";
+ } else if (buffer[0] != 0x00 && buffer[1] != 0x00 &&
+ buffer[2] != 0x00 && buffer[3] != 0x00) {
+ charset = "UTF-8";
+ }
+ } else {
+ // Not enough bytes to sniff, assume UTF-8
+ charset = "UTF-8";
+ }
+ }
+
+ // We should have a unicode charset by now
+ rv = CheckCharset(charset.get());
+ NS_ENSURE_SUCCESS(rv, rv);
+ mDecoder = EncodingUtils::DecoderForEncoding(charset);
+
+ // consume the sniffed bytes
+ rv = ConsumeConverted(mSniffBuffer.get(), mSniffBuffer.Length());
+ NS_ENSURE_SUCCESS(rv, rv);
+ mSniffBuffer.Truncate();
+ }
+
+ if (!aBuffer)
+ return NS_OK;
+
+ if (mNeedsConverter) {
+ rv = ConsumeConverted(aBuffer, aByteLength);
+ } else {
+ uint32_t unichars = aByteLength / sizeof(char16_t);
+ rv = Consume((char16_t *) aBuffer, unichars);
+ }
+
+ return rv;
+}
+
+nsresult
+nsJSONListener::ConsumeConverted(const char* aBuffer, uint32_t aByteLength)
+{
+ nsresult rv;
+ int32_t unicharLength = 0;
+ int32_t srcLen = aByteLength;
+
+ rv = mDecoder->GetMaxLength(aBuffer, srcLen, &unicharLength);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ char16_t* endelems = mBufferedChars.AppendElements(unicharLength);
+ int32_t preLength = unicharLength;
+ rv = mDecoder->Convert(aBuffer, &srcLen, endelems, &unicharLength);
+ if (NS_FAILED(rv))
+ return rv;
+ MOZ_ASSERT(preLength >= unicharLength, "GetMaxLength lied");
+ if (preLength > unicharLength)
+ mBufferedChars.TruncateLength(mBufferedChars.Length() - (preLength - unicharLength));
+ return NS_OK;
+}
+
+nsresult
+nsJSONListener::Consume(const char16_t* aBuffer, uint32_t aByteLength)
+{
+ if (!mBufferedChars.AppendElements(aBuffer, aByteLength))
+ return NS_ERROR_FAILURE;
+
+ return NS_OK;
+}