1 files changed, 147 insertions, 0 deletions
diff --git a/dom/encoding/TextDecoder.cpp b/dom/encoding/TextDecoder.cpp
new file mode 100644
index 000000000..24f7ec166
--- /dev/null
+++ b/dom/encoding/TextDecoder.cpp
@@ -0,0 +1,147 @@
+/* -*- 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/TextDecoder.h"
+#include "mozilla/dom/EncodingUtils.h"
+#include "mozilla/dom/UnionTypes.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "nsContentUtils.h"
+#include <stdint.h>
+
+namespace mozilla {
+namespace dom {
+
+static const char16_t kReplacementChar = static_cast<char16_t>(0xFFFD);
+
+void
+TextDecoder::Init(const nsAString& aLabel, const bool aFatal,
+                  ErrorResult& aRv)
+{
+  nsAutoCString encoding;
+  // Let encoding be the result of getting an encoding from label.
+  // If encoding is failure or replacement, throw a RangeError
+  // (https://encoding.spec.whatwg.org/#dom-textdecoder).
+  if (!EncodingUtils::FindEncodingForLabelNoReplacement(aLabel, encoding)) {
+    nsAutoString label(aLabel);
+    EncodingUtils::TrimSpaceCharacters(label);
+    aRv.ThrowRangeError<MSG_ENCODING_NOT_SUPPORTED>(label);
+    return;
+  }
+  InitWithEncoding(encoding, aFatal);
+}
+
+void
+TextDecoder::InitWithEncoding(const nsACString& aEncoding, const bool aFatal)
+{
+  mEncoding = aEncoding;
+  // If the constructor is called with an options argument,
+  // and the fatal property of the dictionary is set,
+  // set the internal fatal flag of the decoder object.
+  mFatal = aFatal;
+
+  // Create a decoder object for mEncoding.
+  mDecoder = EncodingUtils::DecoderForEncoding(mEncoding);
+
+  if (mFatal) {
+    mDecoder->SetInputErrorBehavior(nsIUnicodeDecoder::kOnError_Signal);
+  }
+}
+
+void
+TextDecoder::Decode(const char* aInput, const int32_t aLength,
+                    const bool aStream, nsAString& aOutDecodedString,
+                    ErrorResult& aRv)
+{
+  aOutDecodedString.Truncate();
+
+  // Run or resume the decoder algorithm of the decoder object's encoder.
+  int32_t outLen;
+  nsresult rv = mDecoder->GetMaxLength(aInput, aLength, &outLen);
+  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<char16_t[]>(outLen + 1);
+  if (!buf) {
+    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  }
+
+  int32_t length = aLength;
+  rv = mDecoder->Convert(aInput, &length, buf.get(), &outLen);
+  MOZ_ASSERT(mFatal || rv != NS_ERROR_ILLEGAL_INPUT);
+  buf[outLen] = 0;
+
+  if (!aOutDecodedString.Append(buf.get(), outLen, fallible)) {
+    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  }
+
+  // If the internal streaming flag of the decoder object is not set,
+  // then reset the encoding algorithm state to the default values
+  if (!aStream) {
+    mDecoder->Reset();
+    if (rv == NS_OK_UDEC_MOREINPUT) {
+      if (mFatal) {
+        aRv.ThrowTypeError<MSG_DOM_DECODING_FAILED>();
+      } else {
+        // Need to emit a decode error manually
+        // to simulate the EOF handling of the Encoding spec.
+        aOutDecodedString.Append(kReplacementChar);
+      }
+    }
+  }
+
+  if (NS_FAILED(rv)) {
+    aRv.ThrowTypeError<MSG_DOM_DECODING_FAILED>();
+  }
+}
+
+void
+TextDecoder::Decode(const Optional<ArrayBufferViewOrArrayBuffer>& aBuffer,
+                    const TextDecodeOptions& aOptions,
+                    nsAString& aOutDecodedString,
+                    ErrorResult& aRv)
+{
+  if (!aBuffer.WasPassed()) {
+    Decode(nullptr, 0, aOptions.mStream, aOutDecodedString, aRv);
+    return;
+  }
+  const ArrayBufferViewOrArrayBuffer& buf = aBuffer.Value();
+  uint8_t* data;
+  uint32_t length;
+  if (buf.IsArrayBufferView()) {
+    buf.GetAsArrayBufferView().ComputeLengthAndData();
+    data = buf.GetAsArrayBufferView().Data();
+    length = buf.GetAsArrayBufferView().Length();
+  } else {
+    MOZ_ASSERT(buf.IsArrayBuffer());
+    buf.GetAsArrayBuffer().ComputeLengthAndData();
+    data = buf.GetAsArrayBuffer().Data();
+    length = buf.GetAsArrayBuffer().Length();
+  }
+  // The other Decode signature takes a signed int, because that's
+  // what nsIUnicodeDecoder::Convert takes as the length.  Throw if
+  // our length is too big.
+  if (length > INT32_MAX) {
+    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  }
+  Decode(reinterpret_cast<char*>(data), length, aOptions.mStream,
+         aOutDecodedString, aRv);
+}
+
+void
+TextDecoder::GetEncoding(nsAString& aEncoding)
+{
+  CopyASCIItoUTF16(mEncoding, aEncoding);
+  nsContentUtils::ASCIIToLower(aEncoding);
+}
+
+} // namespace dom
+} // namespace mozilla