1 files changed, 81 insertions, 0 deletions
diff --git a/dom/encoding/TextEncoder.cpp b/dom/encoding/TextEncoder.cpp
new file mode 100644
index 0000000000..ccd298b389
--- /dev/null
+++ b/dom/encoding/TextEncoder.cpp
@@ -0,0 +1,81 @@
+/* -*- 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