Add m-esr52 at 52.6.0

11 files changed, 1036 insertions, 0 deletions

diff --git a/dom/json/moz.build b/dom/json/moz.build
new file mode 100644
index 000000000..635dca255
--- /dev/null
+++ b/dom/json/moz.build
@@ -0,0 +1,22 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+EXPORTS += [
+    'nsJSON.h',
+]
+
+UNIFIED_SOURCES += [
+    'nsJSON.cpp',
+]
+
+LOCAL_INCLUDES += [
+    '/dom/base',
+]
+
+FINAL_LIBRARY = 'xul'
+
+XPCSHELL_TESTS_MANIFESTS += ['test/unit/xpcshell.ini']
+MOCHITEST_MANIFESTS += ['test/mochitest.ini']
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;
+}
diff --git a/dom/json/nsJSON.h b/dom/json/nsJSON.h
new file mode 100644
index 000000000..fd9fcd774
--- /dev/null
+++ b/dom/json/nsJSON.h
@@ -0,0 +1,94 @@
+/* -*- 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/. */
+
+#ifndef nsJSON_h__
+#define nsJSON_h__
+
+#include "nsIJSON.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsIOutputStream.h"
+#include "nsIUnicodeEncoder.h"
+#include "nsIUnicodeDecoder.h"
+#include "nsIRequestObserver.h"
+#include "nsIStreamListener.h"
+#include "nsTArray.h"
+
+class nsIURI;
+
+class MOZ_STACK_CLASS nsJSONWriter
+{
+public:
+  nsJSONWriter();
+  explicit nsJSONWriter(nsIOutputStream* aStream);
+  virtual ~nsJSONWriter();
+  nsresult SetCharset(const char *aCharset);
+  nsCOMPtr<nsIOutputStream> mStream;
+  nsresult Write(const char16_t *aBuffer, uint32_t aLength);
+  nsString mOutputString;
+  bool DidWrite();
+  void FlushBuffer();
+
+protected:
+  char16_t *mBuffer;
+  uint32_t mBufferCount;
+  bool mDidWrite;
+  nsresult WriteToStream(nsIOutputStream *aStream, nsIUnicodeEncoder *encoder,
+                         const char16_t *aBuffer, uint32_t aLength);
+
+  nsCOMPtr<nsIUnicodeEncoder> mEncoder;
+};
+
+class nsJSON : public nsIJSON
+{
+public:
+  nsJSON();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIJSON
+
+protected:
+  virtual ~nsJSON();
+
+  nsresult EncodeInternal(JSContext* cx,
+                          const JS::Value& val,
+                          nsJSONWriter* writer);
+
+  nsresult DecodeInternal(JSContext* cx,
+                          nsIInputStream* aStream,
+                          int32_t aContentLength,
+                          bool aNeedsConverter,
+                          JS::MutableHandle<JS::Value> aRetVal);
+  nsCOMPtr<nsIURI> mURI;
+};
+
+nsresult
+NS_NewJSON(nsISupports* aOuter, REFNSIID aIID, void** aResult);
+
+class nsJSONListener : public nsIStreamListener
+{
+public:
+  nsJSONListener(JSContext *cx, JS::Value *rootVal, bool needsConverter);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSISTREAMLISTENER
+
+protected:
+  virtual ~nsJSONListener();
+
+  bool mNeedsConverter;
+  JSContext *mCx;
+  JS::Value *mRootVal;
+  nsCOMPtr<nsIUnicodeDecoder> mDecoder;
+  nsCString mSniffBuffer;
+  nsTArray<char16_t> mBufferedChars;
+  nsresult ProcessBytes(const char* aBuffer, uint32_t aByteLength);
+  nsresult ConsumeConverted(const char* aBuffer, uint32_t aByteLength);
+  nsresult Consume(const char16_t *data, uint32_t len);
+};
+
+#endif
diff --git a/dom/json/test/mochitest.ini b/dom/json/test/mochitest.ini
new file mode 100644
index 000000000..f09974d3f
--- /dev/null
+++ b/dom/json/test/mochitest.ini
@@ -0,0 +1 @@
+[test_json.html]
diff --git a/dom/json/test/test_json.html b/dom/json/test/test_json.html
new file mode 100644
index 000000000..23e41e179
--- /dev/null
+++ b/dom/json/test/test_json.html
@@ -0,0 +1,40 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=408838
+-->
+<head>
+  <title>Test for Bug 408838</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=408838">Mozilla Bug 408838</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for Bug 408838 **/
+
+is(typeof JSON, "object", "JSON should be present");
+is(typeof JSON.parse, "function", "JSON.parse should be present");
+is(typeof JSON.stringify, "function", "JSON.stringify should be present");
+
+var str = '{"foo":[1,{"bar":"baz"}],"qux":1234.1234,"quux":[true,false,null,"hmm",9,[]]}';
+var x = JSON.parse(str);
+
+is(x.foo[0], 1, "JSON integer");
+is(x.foo[1].bar, "baz", "JSON string in object");
+is(x.qux, 1234.1234, "JSON float");
+
+var y = JSON.stringify(x);
+is(y, str, "JSON round trip");
+
+</script>
+</pre>
+</body>
+</html>
+
diff --git a/dom/json/test/unit/decodeFromStream-01.json b/dom/json/test/unit/decodeFromStream-01.json
new file mode 100644
index 000000000..258658753
--- /dev/null
+++ b/dom/json/test/unit/decodeFromStream-01.json
@@ -0,0 +1,7 @@
+{
+    "JSON Test Pattern pass3": {
+        "The outermost value": "must be an object or array.",
+        "In this test": "It is an object."
+    }
+}
+
diff --git a/dom/json/test/unit/decodeFromStream-small.json b/dom/json/test/unit/decodeFromStream-small.json
new file mode 100644
index 000000000..9e26dfeeb
--- /dev/null
+++ b/dom/json/test/unit/decodeFromStream-small.json
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/dom/json/test/unit/test_decodeFromStream.js b/dom/json/test/unit/test_decodeFromStream.js
new file mode 100644
index 000000000..eb30d2619
--- /dev/null
+++ b/dom/json/test/unit/test_decodeFromStream.js
@@ -0,0 +1,29 @@
+var Ci = Components.interfaces;
+var Cc = Components.classes;
+
+var nativeJSON = Cc["@mozilla.org/dom/json;1"].createInstance(Ci.nsIJSON);
+
+function run_test()
+{
+  function read_file(path)
+  {
+    try
+    {
+      var f = do_get_file(path);
+      var istream = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(Ci.nsIFileInputStream);
+      istream.init(f, -1, -1, false);
+      return nativeJSON.decodeFromStream(istream, istream.available());
+    }
+    finally
+    {
+      istream.close();
+    }
+  }
+
+  var x = read_file("decodeFromStream-01.json");
+  do_check_eq(x["JSON Test Pattern pass3"]["The outermost value"], "must be an object or array.");
+  do_check_eq(x["JSON Test Pattern pass3"]["In this test"], "It is an object.");
+
+  x = read_file("decodeFromStream-small.json");
+  do_check_eq(x.toSource(), "({})", "empty object parsed");
+}
diff --git a/dom/json/test/unit/test_decode_long_input.js b/dom/json/test/unit/test_decode_long_input.js
new file mode 100644
index 000000000..c7a40c784
--- /dev/null
+++ b/dom/json/test/unit/test_decode_long_input.js
@@ -0,0 +1,32 @@
+// This tests breaking long input across parser buffers
+var Ci = Components.interfaces;
+var Cc = Components.classes;
+
+var nativeJSON = Cc["@mozilla.org/dom/json;1"].createInstance(Ci.nsIJSON);
+
+var x = {"Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"2Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"3Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"6Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"7Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"8Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"9Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"10Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"11Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"12Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"13Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"14Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"15Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"16Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
+"17Lorem ipsum his ponderum delicatissimi ne, at noster dolores urbanitas pro, cibo elaboraret no his. Ea dicunt maiorum usu. Ad appareat facilisis mediocritatem eos. Tale graeci mentitum in eos, hinc insolens at nam. Graecis nominavi aliquyam eu vix.":"Id solet assentior sadipscing pro. Et per atqui graecis, usu quot viris repudiandae ei, mollis evertitur an nam. At nam dolor ignota, liber labore omnesque ea mei, has movet voluptaria in. Vel an impetus omittantur. Vim movet option salutandi ex, ne mei ignota corrumpit. Mucius comprehensam id per. Est ea putant maiestatis.",
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+}
+
+var y = nativeJSON.encode(x);
+var z = nativeJSON.decode(y);
+
+function run_test()
+{
+  for (var i in x)
+    do_check_eq(x[i], z[i]);
+}
diff --git a/dom/json/test/unit/test_encode.js b/dom/json/test/unit/test_encode.js
new file mode 100644
index 000000000..88907efa3
--- /dev/null
+++ b/dom/json/test/unit/test_encode.js
@@ -0,0 +1,143 @@
+var Ci = Components.interfaces;
+var Cc = Components.classes;
+
+var nativeJSON = Cc["@mozilla.org/dom/json;1"].createInstance(Ci.nsIJSON);
+
+var dirSvc = Cc["@mozilla.org/file/directory_service;1"].getService(Ci.nsIProperties);
+var workingDir = dirSvc.get("TmpD", Ci.nsIFile);
+
+var outputName = "json-test-output";
+var outputDir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
+outputDir.initWithFile(workingDir);
+outputDir.append(outputName);
+
+if (!outputDir.exists()) {
+  outputDir.create(Ci.nsIFile.DIRECTORY_TYPE, 0o777);
+} else if (!outputDir.isDirectory()) {
+  do_throw(outputName + " is not a directory?")
+}
+
+function testStringEncode()
+{
+  var obj1 = {a:1};
+  var obj2 = {foo:"bar"};
+  do_check_eq(nativeJSON.encode(obj1), '{"a":1}');
+  do_check_eq(nativeJSON.encode(obj2), '{"foo":"bar"}');
+
+  do_check_eq(nativeJSON.encode(), null);
+
+  // useless roots are dropped
+  do_check_eq(nativeJSON.encode(null), null);
+  do_check_eq(nativeJSON.encode(""), null);
+  do_check_eq(nativeJSON.encode(undefined), null);
+  do_check_eq(nativeJSON.encode(5), null);
+  do_check_eq(nativeJSON.encode(function(){}), null);
+  do_check_eq(nativeJSON.encode(dump), null);
+
+  // All other testing should occur in js/src/tests/ecma_5/JSON/ using
+  // the otherwise-exactly-identical JSON.stringify.
+}
+
+function testToJSON() {
+  var obj1 = {a:1};
+  var obj2 = {foo:"bar"};
+  do_check_eq(nativeJSON.encode({toJSON: () => obj1}), '{"a":1}');
+  do_check_eq(nativeJSON.encode({toJSON: () => obj2}), '{"foo":"bar"}');
+  
+  do_check_eq(nativeJSON.encode({toJSON: () => null}), null);
+  do_check_eq(nativeJSON.encode({toJSON: () => ""}), null);
+  do_check_eq(nativeJSON.encode({toJSON: () => undefined }), null);
+  do_check_eq(nativeJSON.encode({toJSON: () => 5}), null);
+  do_check_eq(nativeJSON.encode({toJSON: () => function(){}}), null);
+  do_check_eq(nativeJSON.encode({toJSON: () => dump}), null);
+}
+
+function testThrowingToJSON() {
+  var obj1 = {
+    "b": 1,
+    "c": 2,
+    toJSON: function() { throw("uh oh"); }
+  };
+  try {
+    var y = nativeJSON.encode(obj1);
+    throw "didn't throw";
+  } catch (ex) {
+    do_check_eq(ex, "uh oh");
+  }
+
+  var obj2 = {
+    "b": 1,
+    "c": 2,
+    get toJSON() { throw("crash and burn"); }
+  };
+  try {
+    var y = nativeJSON.encode(obj2);
+    throw "didn't throw";
+  } catch (ex) {
+    do_check_eq(ex, "crash and burn");
+  }
+}
+
+function testOutputStreams() {
+  function writeToFile(obj, charset, writeBOM) {
+    var jsonFile = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
+    jsonFile.initWithFile(outputDir);
+    jsonFile.append("test.json");
+    jsonFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);
+    var stream = Cc["@mozilla.org/network/file-output-stream;1"].createInstance(Ci.nsIFileOutputStream);
+    try {
+      stream.init(jsonFile, 0x04 | 0x08 | 0x20, 0o600, 0); // write, create, truncate
+      nativeJSON.encodeToStream(stream, charset, writeBOM, obj);
+    } finally {
+      stream.close();
+    }
+    return jsonFile;
+  }
+
+  var pairs = [
+    ["{}", {}],
+    ['{"foo":"bar"}', {"foo":"bar"}],
+    ['{"null":null}', {"null":null}],
+    ['{"five":5}', {"five":5}],
+    ['{"true":true}', {"true":true}],
+    ['{"x":{"y":"z"}}', {"x":{"y":"z"}}],
+    ['{"w":{"x":{"y":"z"}}}', {"w":{"x":{"y":"z"}}}],
+    ["[]", []],
+    ['[1,2,3]', [1,2,3]],
+    ['[1,null,3]',[1,,3]],
+  ];
+  for (var i = 0; i < pairs.length; i++)
+  {
+    var pair = pairs[i];
+    if (pair[1] && (typeof pair[1] == "object")) {
+      var utf8File = writeToFile(pair[1], "UTF-8", false);
+      var utf16LEFile = writeToFile(pair[1], "UTF-16LE", false);
+      var utf16BEFile = writeToFile(pair[1], "UTF-16BE", false);
+
+      // all ascii with no BOMs, so this will work
+      do_check_eq(utf16LEFile.fileSize / 2, utf8File.fileSize);
+      do_check_eq(utf16LEFile.fileSize, utf16BEFile.fileSize);
+    }
+  }
+
+  // check BOMs
+  // the clone() calls are there to work around -- bug 410005
+  var f = writeToFile({},"UTF-8", true).clone();
+  do_check_eq(f.fileSize, 5);
+  var f = writeToFile({},"UTF-16LE", true).clone();
+  do_check_eq(f.fileSize, 6);
+  var f = writeToFile({},"UTF-16BE", true).clone();
+  do_check_eq(f.fileSize, 6);
+  
+  outputDir.remove(true);
+}
+
+function run_test()
+{
+  testStringEncode();
+  testToJSON();
+  testThrowingToJSON();
+  
+  testOutputStreams();
+  
+}
diff --git a/dom/json/test/unit/xpcshell.ini b/dom/json/test/unit/xpcshell.ini
new file mode 100644
index 000000000..68c4524a5
--- /dev/null
+++ b/dom/json/test/unit/xpcshell.ini
@@ -0,0 +1,11 @@
+[DEFAULT]
+head =
+tail =
+support-files =
+  decodeFromStream-01.json
+  decodeFromStream-small.json
+
+[test_decode_long_input.js]
+[test_decodeFromStream.js]
+[test_encode.js]
+