diff -r 000000000000 -r 6474c204b198 intl/uconv/src/nsConverterOutputStream.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/intl/uconv/src/nsConverterOutputStream.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,143 @@
+/* vim:set expandtab ts=4 sw=4 sts=4 cin: */
+/* 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 "nsCOMPtr.h"
+
+#include "nsIOutputStream.h"
+#include "nsICharsetConverterManager.h"
+
+#include "nsConverterOutputStream.h"
+#include "nsServiceManagerUtils.h"
+
+NS_IMPL_ISUPPORTS(nsConverterOutputStream,
+                  nsIUnicharOutputStream,
+                  nsIConverterOutputStream)
+
+nsConverterOutputStream::~nsConverterOutputStream()
+{
+    Close();
+}
+
+NS_IMETHODIMP
+nsConverterOutputStream::Init(nsIOutputStream* aOutStream,
+                              const char*      aCharset,
+                              uint32_t         aBufferSize /* ignored */,
+                              char16_t        aReplacementChar)
+{
+    NS_PRECONDITION(aOutStream, "Null output stream!");
+
+    if (!aCharset)
+        aCharset = "UTF-8";
+
+    nsresult rv;
+    nsCOMPtr<nsICharsetConverterManager> ccm =
+        do_GetService(NS_CHARSETCONVERTERMANAGER_CONTRACTID, &rv);
+    if (NS_FAILED(rv)) return rv;
+
+    rv = ccm->GetUnicodeEncoder(aCharset, getter_AddRefs(mConverter));
+    if (NS_FAILED(rv))
+        return rv;
+
+    mOutStream = aOutStream;
+
+    int32_t behaviour = aReplacementChar ? nsIUnicodeEncoder::kOnError_Replace
+                                         : nsIUnicodeEncoder::kOnError_Signal;
+    return mConverter->
+        SetOutputErrorBehavior(behaviour,
+                               nullptr,
+                               aReplacementChar);
+}
+
+NS_IMETHODIMP
+nsConverterOutputStream::Write(uint32_t aCount, const char16_t* aChars,
+                               bool* aSuccess)
+{
+    if (!mOutStream) {
+        NS_ASSERTION(!mConverter, "Closed streams shouldn't have converters");
+        return NS_BASE_STREAM_CLOSED;
+    }
+    NS_ASSERTION(mConverter, "Must have a converter when not closed");
+
+    int32_t inLen = aCount;
+
+    int32_t maxLen;
+    nsresult rv = mConverter->GetMaxLength(aChars, inLen, &maxLen);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsAutoCString buf;
+    buf.SetLength(maxLen);
+    if (buf.Length() != (uint32_t) maxLen)
+        return NS_ERROR_OUT_OF_MEMORY;
+
+    int32_t outLen = maxLen;
+    rv = mConverter->Convert(aChars, &inLen, buf.BeginWriting(), &outLen);
+    if (NS_FAILED(rv))
+        return rv;
+    if (rv == NS_ERROR_UENC_NOMAPPING) {
+        // Yes, NS_ERROR_UENC_NOMAPPING is a success code
+        return NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
+    }
+    NS_ASSERTION((uint32_t) inLen == aCount,
+                 "Converter didn't consume all the data!");
+
+    uint32_t written;
+    rv = mOutStream->Write(buf.get(), outLen, &written);
+    *aSuccess = NS_SUCCEEDED(rv) && written == uint32_t(outLen);
+    return rv;
+
+}
+
+NS_IMETHODIMP
+nsConverterOutputStream::WriteString(const nsAString& aString, bool* aSuccess)
+{
+    int32_t inLen = aString.Length();
+    nsAString::const_iterator i;
+    aString.BeginReading(i);
+    return Write(inLen, i.get(), aSuccess);
+}
+
+NS_IMETHODIMP
+nsConverterOutputStream::Flush()
+{
+    if (!mOutStream)
+        return NS_OK; // Already closed.
+
+    char buf[1024];
+    int32_t size = sizeof(buf);
+    nsresult rv = mConverter->Finish(buf, &size);
+    NS_ASSERTION(rv != NS_OK_UENC_MOREOUTPUT,
+                 "1024 bytes ought to be enough for everyone");
+    if (NS_FAILED(rv))
+        return rv;
+    if (size == 0)
+        return NS_OK;
+
+    uint32_t written;
+    rv = mOutStream->Write(buf, size, &written);
+    if (NS_FAILED(rv)) {
+        NS_WARNING("Flush() lost data!");
+        return rv;
+    }
+    if (written != uint32_t(size)) {
+        NS_WARNING("Flush() lost data!");
+        return NS_ERROR_LOSS_OF_SIGNIFICANT_DATA;
+    }
+    return rv;
+}
+
+NS_IMETHODIMP
+nsConverterOutputStream::Close()
+{
+    if (!mOutStream)
+        return NS_OK; // Already closed.
+
+    nsresult rv1 = Flush();
+
+    nsresult rv2 = mOutStream->Close();
+    mOutStream = nullptr;
+    mConverter = nullptr;
+    return NS_FAILED(rv1) ? rv1 : rv2;
+}
+