gecko/dom/encoding/TextDecoder.h

129 lines
3.7 KiB
C++

/* 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 mozilla_dom_textdecoder_h_
#define mozilla_dom_textdecoder_h_
#include "jsapi.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/TextDecoderBinding.h"
#include "mozilla/dom/TypedArray.h"
#include "mozilla/ErrorResult.h"
#include "nsIUnicodeDecoder.h"
#include "nsString.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
namespace mozilla {
namespace dom {
class TextDecoder : public nsISupports, public nsWrapperCache
{
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(TextDecoder)
// The WebIDL constructor.
static already_AddRefed<TextDecoder>
Constructor(nsISupports* aGlobal,
const nsAString& aEncoding,
const TextDecoderOptions& aFatal,
ErrorResult& aRv)
{
nsRefPtr<TextDecoder> txtDecoder = new TextDecoder(aGlobal);
txtDecoder->Init(aEncoding, aFatal, aRv);
if (aRv.Failed()) {
return nullptr;
}
return txtDecoder.forget();
}
TextDecoder(nsISupports* aGlobal)
: mGlobal(aGlobal), mFatal(false), mOffset(0), mIsUTF16Family(false)
{
MOZ_ASSERT(aGlobal);
SetIsDOMBinding();
}
virtual
~TextDecoder()
{}
virtual JSObject*
WrapObject(JSContext* aCx, JSObject* aScope, bool* aTriedToWrap)
{
return TextDecoderBinding::Wrap(aCx, aScope, this, aTriedToWrap);
}
nsISupports*
GetParentObject()
{
return mGlobal;
}
/**
* Return the encoding name.
*
* @param aEncoding, current encoding.
*/
void GetEncoding(nsAString& aEncoding);
/**
* Decodes incoming byte stream of characters in charset indicated by
* encoding.
*
* The encoding algorithm state is reset if aOptions.stream is not set.
*
* If the fatal flag is set then a decoding error will throw EncodingError.
* Else the decoder will return a decoded string with replacement
* character(s) for unidentified character(s).
*
* @param aView, incoming byte stream of characters to be decoded to
* to UTF-16 code points.
* @param aOptions, indicates if streaming or not.
* @param aOutDecodedString, decoded string of UTF-16 code points.
* @param aRv, error result.
*/
void Decode(const ArrayBufferView* aView,
const TextDecodeOptions& aOptions,
nsAString& aOutDecodedString,
ErrorResult& aRv);
private:
nsCString mEncoding;
nsCOMPtr<nsIUnicodeDecoder> mDecoder;
nsCOMPtr<nsISupports> mGlobal;
bool mFatal;
uint8_t mOffset;
char mInitialBytes[3];
bool mIsUTF16Family;
/**
* Validates provided encoding and throws an exception if invalid encoding.
* If no encoding is provided then mEncoding is default initialised to "utf-8".
*
* @param aEncoding Optional encoding (case insensitive) provided.
* Default value is "utf-8" if no encoding is provided.
* @param aFatal aFatal, indicates whether to throw an 'EncodingError'
* exception or not.
* @return aRv EncodingError exception else null.
*/
void Init(const nsAString& aEncoding,
const TextDecoderOptions& aFatal,
ErrorResult& aRv);
// Internal helper functions.
void ResetDecoder();
void HandleBOM(const char*& aData, uint32_t& aLength,
const TextDecodeOptions& aOptions,
nsAString& aOutString, ErrorResult& aRv);
void FeedBytes(const char* aBytes, nsAString* aOutString = nullptr);
};
} // dom
} // mozilla
#endif // mozilla_dom_textdecoder_h_