/* 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/. */

#if !defined(_nsHTTPCompressConv_h_)
#  define _nsHTTPCompressConv_h_ 1

#  include "nsIStreamConverter.h"
#  include "nsICompressConvStats.h"
#  include "nsIThreadRetargetableStreamListener.h"
#  include "nsCOMPtr.h"
#  include "nsString.h"
#  include "mozilla/Atomics.h"
#  include "mozilla/Mutex.h"

#  include "zlib.h"

class nsIStringInputStream;

#  define NS_HTTPCOMPRESSCONVERTER_CID          \
    {/* 66230b2b-17fa-4bd3-abf4-07986151022d */ \
     0x66230b2b,                                \
     0x17fa,                                    \
     0x4bd3,                                    \
     {0xab, 0xf4, 0x07, 0x98, 0x61, 0x51, 0x02, 0x2d}}

#  define HTTP_DEFLATE_TYPE "deflate"
#  define HTTP_GZIP_TYPE "gzip"
#  define HTTP_X_GZIP_TYPE "x-gzip"
#  define HTTP_COMPRESS_TYPE "compress"
#  define HTTP_X_COMPRESS_TYPE "x-compress"
#  define HTTP_BROTLI_TYPE "br"
#  define HTTP_IDENTITY_TYPE "identity"
#  define HTTP_UNCOMPRESSED_TYPE "uncompressed"
#  define HTTP_ZSTD_TYPE "zstd"
#  define HTTP_ZST_TYPE "zst"
#  define HTTP_BROTLI_DICTIONARY_TYPE "dcb"
#  define HTTP_ZSTD_DICTIONARY_TYPE "dcz"

#  define GZIP_MAGIC_0 0x1f
#  define GZIP_MAGIC_1 0x8b

#  define ZSTD_MAGIC_0 0x28
#  define ZSTD_MAGIC_1 0xb5
#  define ZSTD_MAGIC_2 0x2f
#  define ZSTD_MAGIC_3 0xfd

// Not magic bytes, but common brotli first bytes
#  define BROTLI_BYTE_0 0xce
#  define BROTLI_BYTE_1 0xb2

namespace mozilla {
namespace net {

class BrotliWrapper;
class ZstdWrapper;

class nsHTTPCompressConv : public nsIStreamConverter,
                           public nsICompressConvStats {
 public:
  // nsISupports methods
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIREQUESTOBSERVER
  NS_DECL_NSISTREAMLISTENER
  NS_DECL_NSICOMPRESSCONVSTATS
  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER

  // nsIStreamConverter methods
  NS_DECL_NSISTREAMCONVERTER

  nsHTTPCompressConv();

  using CompressMode = enum {
    HTTP_COMPRESS_GZIP,
    HTTP_COMPRESS_DEFLATE,
    HTTP_COMPRESS_COMPRESS,
    HTTP_COMPRESS_BROTLI,
    HTTP_COMPRESS_IDENTITY,
    HTTP_COMPRESS_ZSTD,
    HTTP_COMPRESS_BROTLI_DICTIONARY,
    HTTP_COMPRESS_ZSTD_DICTIONARY,
  };

 private:
  virtual ~nsHTTPCompressConv();

  nsCOMPtr<nsIStreamListener> mListener
      MOZ_GUARDED_BY(mMutex);  // gets converted data via OnDataAvailable()
  Atomic<CompressMode, Relaxed> mMode{HTTP_COMPRESS_IDENTITY};

  unsigned char* mOutBuffer{nullptr};
  unsigned char* mInpBuffer{nullptr};

  uint32_t mOutBufferLen{0};
  uint32_t mInpBufferLen{0};

  UniquePtr<BrotliWrapper> mBrotli;
  UniquePtr<ZstdWrapper> mZstd;

  nsCOMPtr<nsIStringInputStream> mStream;

  static nsresult BrotliHandler(nsIInputStream* stream, void* closure,
                                const char* dataIn, uint32_t, uint32_t avail,
                                uint32_t* countRead);

  static nsresult ZstdHandler(nsIInputStream* stream, void* closure,
                              const char* dataIn, uint32_t, uint32_t avail,
                              uint32_t* countRead);

  nsresult do_OnDataAvailable(nsIRequest* request, uint64_t aSourceOffset,
                              const char* buffer, uint32_t aCount);

  bool mCheckHeaderDone{false};
  Atomic<bool> mStreamEnded{false};
  bool mStreamInitialized{false};
  bool mDummyStreamInitialised{false};
  bool mFailUncleanStops;
  Atomic<bool> mDispatchToMainThread{false};

  z_stream d_stream{};
  unsigned mLen{0}, hMode{0}, mSkipCount{0}, mFlags{0};

  uint32_t check_header(nsIInputStream* iStr, uint32_t streamLen, nsresult* rs);

  void ReportDecodingErrorWithSite(const nsACString& aLabel);
  Atomic<uint32_t, Relaxed> mDecodedDataLength{0};

  // Cached on main thread in OnStartRequest; read from any thread thereafter.
  Atomic<bool, Relaxed> mIsPrivateBrowsing{false};
  nsCString mSite;

  mutable mozilla::Mutex mMutex{"nsHTTPCompressConv"};
};

}  // namespace net
}  // namespace mozilla

#endif